Cell Fatigue - CFS/ME Biology

CFS & gut function (dysbiosis, leaky gut & inflammation)

2011-09-11T10:15:00.000-07:00

A role for general gut dysfunction in the CFS pathophysiology is steadily increasing (for review see [1]). Changes reported in the gut in CFS include those relating digestive function, microbial balance, gut-barrier function and general inflammation.

Dysbiosis

Various studies have shown changes to the gut microbiota in CFS, such as lowered levels of healthful probiotics (e.g. bifidobacteria & e.coli) and increased growth of potentially pathogenic organisms (e.g. aerobic bacteria) [1-3]. Furthermore, overgrowth of certain anaerobic bacteria (e.g. streptococcus, enterococcus & prevotella) may also be a major part of the CFS pathophysiology [2-5]. These bacteria may produce large amounts of toxic substances such as D-lactate, which can then be absorbed through the cells in the intestine. D-lactate (not to be confused with endogenously produced L-lactate) cannot be efficiently metabolised in humans and may produce symptoms of lactate acidosis, which includes neurological complaints. Overgrowth of these bacteria was also associated with high H2S (hydrogen sulphide) levels in CFS [5], although this could be of endogenous metabolic origin. H2S is toxic through suppression of aerobic energy metabolism, and has a vasodilative effect on the circulatory system. For more information on H2S and D-lactate production see my H2S and Lactate posts.

Some of the bacterial overgrowth seen in CFS may be quite similar to the well-recognised medical condition SIBO (small intestine bacterial overgrowth), so research relating to the pathogenesis and treatment of this condition may also be relevant to CFS. Research suggests high risk factors for developing SIBO include hypochloridia (low stomach acid), immunodeficiency, poor motility/peristalsis and morphological/anatomical changes amongst other factors [6]. Treatments for SIBO include antibiotics and natural antimicrobials such as peppermint oil [7,8]; other plant 'essential oils' with antimicrobial activity may also have therapeutic potential. With regards to CFS, a couple of studies have shown some significant benefit of probiotic supplementation on neurocognitive function and mood in CFS [9,10].

Leaky gut

There is consistent evidence for leaky gut and LPS (lipopolysaccharide)-induced immune activation in CFS [5,11-14]; related treatment has been associated with significant improvement and even remission in some cases. In particular research by Maes et al. has implicated translocation of gram-negative bacteria (as detected via serum IgA and IgM) and subsequent gut-derived systemic inflammation in CFS [12-14]. These findings corroborate with other studies documenting increased basal expression of inflammatory pathways in CFS such as iNOS, COX2, NF-kB and several inflammatory cytokines [1,15-20]. Treatment of leaky gut with various NAIOs (e.g. glutamine, NAC, zinc, curcumin etc) and a ‘leaky gut diet’ is associated with normalisation of serum antibody responses to gram-negative bacteria and correlating symptom improvement in CFS [13].

References

[1] S.E. Lakhan, A. Kirchgessner, Gut inflammation in chronic fatigue syndrome., Nutrition & Metabolism. 7 (2010) 79.

[2] A.C. Logan, A. Venket Rao, D. Irani, Chronic fatigue syndrome: lactic acid bacteria may be of therapeutic value., Medical Hypotheses. 60 (2003) 915-23.

[3] J.R. Sheedy, R.E.H. Wettenhall, D. Scanlon, P.R. Gooley, D.P. Lewis, N. McGregor, et al., Increased d-lactic Acid intestinal bacteria in patients with chronic fatigue syndrome., In Vivo (Athens, Greece). 23 (2009) 621-8.

[4] M.D. Lemle, Hypothesis: chronic fatigue syndrome is caused by dysregulation of hydrogen sulfide metabolism., Medical Hypotheses. 72 (2009) 108-9.

[5] K. De Meirleir, C. Roelant, M. Fremont, Research on Extremely Disabled M.E. Patients Reveals the True Nature of the Disorder., (2009).

[6] J. Bures, J. Cyrany, D. Kohoutova, M. Förstl, S. Rejchrt, J. Kvetina, et al., Small intestinal bacterial overgrowth syndrome., World Journal of Gastroenterology : WJG. 16 (2010) 2978-90.

[7] A.R. Gaby, Treatment with enteric-coated peppermint oil reduced small-intestinal bacterial overgrowth in a patient with irritable bowel syndrome., Alternative Medicine Review : A Journal of Clinical Therapeutic. 8 (2003) 3; author reply 4-5.

[8] G. Cappello, M. Spezzaferro, L. Grossi, L. Manzoli, L. Marzio, Peppermint oil (Mintoil) in the treatment of irritable bowel syndrome: a prospective double blind placebo-controlled randomized trial., Digestive and Liver Disease : Official Journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver. 39 (2007) 530-6.

[9] A.V. Rao, A.C. Bested, T.M. Beaulne, M.A. Katzman, C. Iorio, J.M. Berardi, et al., A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome., Gut Pathogens. 1 (2009) 6.

[10] A. Sullivan, C.E. Nord, B. Evengård, Effect of supplement with lactic-acid producing bacteria on fatigue and physical activity in patients with chronic fatigue syndrome., Nutrition Journal. 8 (2009) 4.

[11] M. Maes, F. Coucke, J.-C. Leunis, Normalization of the increased translocation of endotoxin from gram negative enterobacteria (leaky gut) is accompanied by a remission of chronic fatigue syndrome., Neuro Endocrinology Letters. 28 (2007) 739-44.

[12] M. Maes, I. Mihaylova, J.-C. Leunis, Increased serum IgA and IgM against LPS of enterobacteria in chronic fatigue syndrome (CFS): indication for the involvement of gram-negative enterobacteria in the etiology of CFS and for the presence of an increased gut-intestinal permeability., Journal of Affective Disorders. 99 (2007) 237-40.

[13] M. Maes, J.-C. Leunis, Normalization of leaky gut in chronic fatigue syndrome (CFS) is accompanied by a clinical improvement: effects of age, duration of illness and the translocation of LPS from gram-negative bacteria., Neuro Endocrinology Letters. 29 (2008) 902-10.

[14] M. Maes, F.N.M. Twisk, M. Kubera, K. Ringel, J.-C. Leunis, M. Geffard, Increased IgA responses to the LPS of commensal bacteria is associated with inflammation and activation of cell-mediated immunity in chronic fatigue syndrome., Journal of Affective Disorders. (2011).

[15] M. Maes, I. Mihaylova, E. Bosmans, Not in the mind of neurasthenic lazybones but in the cell nucleus: patients with chronic fatigue syndrome have increased production of nuclear factor kappa beta., Neuro Endocrinology Letters. 28 (2007) 456-62.

[16] M. Maes, I. Mihaylova, M. Kubera, E. Bosmans, Not in the mind but in the cell: increased production of cyclo-oxygenase-2 and inducible NO synthase in chronic fatigue syndrome., Neuro Endocrinology Letters. 28 (2007) 463-9.

[17] P. Scully, D.P. McKernan, J. Keohane, D. Groeger, F. Shanahan, T.G. Dinan, et al., Plasma cytokine profiles in females with irritable bowel syndrome and extra-intestinal co-morbidity., The American Journal of Gastroenterology. 105 (2010) 2235-43.

[18] N. Carlo-Stella, C. Badulli, A. De Silvestri, L. Bazzichi, M. Martinetti, L. Lorusso, et al., A first study of cytokine genomic polymorphisms in CFS: Positive association of TNF-857 and IFNgamma 874 rare alleles., Clinical and Experimental Rheumatology. 24 (2006) 179-82.

[19] V.A. Spence, G. Kennedy, J.J.F. Belch, A. Hill, F. Khan, Low-grade inflammation and arterial wave reflection in patients with chronic fatigue syndrome., Clinical Science (London, England : 1979). 114 (2008) 561-6.

[20] M. Maes, F.N.M. Twisk, M. Kubera, K. Ringel, Evidence for inflammation and activation of cell-mediated immunity in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Increased interleukin-1, tumor necrosis factor-α, PMN-elastase, lysozyme and neopterin., Journal of Affective Disorders. (2011).

Depression: Current and future hypotheses

2011-08-06T05:45:00.000-07:00

The major dominating depression hypothesis in biological science over the past half century has been the monoamine hypothesis (1965>). This hypothesis posits that depression is caused by deficiency of monoamine neurotransmitters (serotonin, dopamine and noradrenaline), which was later refined mostly to serotonin (at least in the mainstream). This hypothesis is based primarily upon the observation that serotonergic agents are effective in treating depression. This is the oldest depression hypothesis, and the one which most clinical antidepressants are still based upon. Through the media it has become ingrained into the consciousness of mass culture (for review see [1]), and speaks of a simple reductionist view of mood which parallels a reductionist pharmacological understanding of disease. In its raw form (e.g. serotonin deficiency as the underlying cause of depression) this hypothesis has been shaken in science. Below I will quickly go through some of the main evidence arguing for and against this hypothesis.

The monoamines in depression

An obvious place to start to unravel the role of monoamines in mood is to modify their levels in healthy controls and depressed patients. Studies through the late 1900s showed that inducing monoamine deficiency in healthy, depressed or recovered depression patients only produced depressive symptoms in recovered patients who had been treated by drugs acting upon the respective monoamine system [2]. However more recent ATD (acute tryptophan depletion) experiments in healthy individuals have revealed a more subtle role of serotonin in mood memory bias [3-6]. There are also cases of genetic monoamine deficiency in humans; genetic deficiency of sepiapterin reductase leads to a combined deficit of serotonin and dopamine, causing dopamine-responsive parkinsonism and serotonin-responsive eating disorder, cognition, and ultradian sleep-wake rhythm (melatonin deficiency), but no depression [7]. Perhaps the best support for gross monoamine deficiency in depression are in vivo reports of increased MAO-A activity [8-10] and inconsistent reports of lowered serum tryptophan [11].

In reality dysfunction of neurotransmitter systems in depression could occur at multiple levels beyond their basic metabolism (synthesis, reuptake and catabolism). For instance the serotonin system comprises of a family of 5-HT (1-7) receptors further divided into subtypes which are heterogeneously distributed in the body and activated by serotonin (5-HT). All these receptors have differing effects on the postsynaptic neuron, but most of which are metabotropic, so serve to modulate specific intracellular pathways. The serotonin system also comprises of presynaptic autoreceptors which homeostatically regulate serotonin release. The past decade of research into synaptic plasticity has taught us that receptors are not fixed in the nervous system, in fact many are extremely dynamic and their expression is controlled by a variety of environmental factors/stimuli. Overall, in vivo brain imaging studies looking directly for monoamine dysfunction in depression have so far failed to consistently support monoamine hypotheses [12], and some post-mortem receptor-level studies have shown decreased 5-HT1A binding [13], and increased 5-HT2 expression [14,15]. These studies above both justify and limit the role of serotonin in depression, especially when considered in context of the plethora of other abnormalities found in depression, some of which are discussed below.

New paradigms for understanding depression

The serotonin hypothesis of depression is endlessly challenged by observations made on the therapeutic and physiological activity of antidepressant agents. For instance current serotonergic antidepressants (e.g. SSRI & SNRI) typically take weeks to bring about clinical symptom improvement despite fairly instant blockade of serotonin uptake, a fact which may partly be attributable to the homeostatic activity of 5-HT autoreceptors [16]. Serotonergic antidepressants also only tend to work in 50% of patients, and many treatments which have no primary effect on monoamine systems have strong antidepressant effects (e.g. glutamatergic agents, neuropeptide modulators, neurotrophic modulators and NOS antagonists). 5-HT1A is often regarded as the major antidepressant target of serotonergic medications, however one of the most effective treatments for TRD (treatment-resistant depression) is ECT (electro-convulsive therapy) which seems to have no effect on 5-HT1A activity [17], but instead promotes neurotrophic and glutamatergic modifications [18,19]. In fact neurotrophic pathways have been shown to be required for the antidepressant activity of serotonergic drugs [20], and glutamatergic drugs such as NMDA antagonists have over the past 10 years displayed remarkably rapid and robust antidepressant activity in animals and humans [19,21]. A single IV dose of ketamine (NMDA antagonist) can send TRD patients into remission within hours, an effect which is sustained for over a week; unfortunately these drugs are typically too dangerous for clinical use. This leads us to the current understanding of how serotonergic antidepressants may at least partially work: by indirectly modulating downstream intracellular targets which promote structural changes. Serotonergic antidepressants have been shown to modulate the glutamate system, nNOS (neuronal nitric oxide synthase), and neurotrophic and inflammatory cascades amongst other systems.

Indeed it has become clear that there is far more to depression than serotonin dysfunction and even simple gross chemical imbalances. In the brain, at the molecular level depression is associated with changes to many receptor systems, intracellular signalling pathways, and redox [19,22]; at the neuroanatomical-level depression is associated with glia loss [23], altered neuronal morphology, and atrophy to structures such as the hippocampus and PFC [22]. Even throughout the body depression is associated with biological changes such as inflammation and metabolic disturbances. For instance recent research has linked body-wide inflammation to mood disorders [11]; IFN-α treatment causes inflammation-induced depression in humans which correlates with CSF KA and quinolinic acid (NMDA agonist) concentrations rather than serotonin depletion [24]. This new depression pathway is supported by a recent study which found increased microglial quinolinic acid in sub-regions of the anterior cingulate cortex in severe depression [25]. Recent studies have also consistently found massive changes in NMDA receptor subunit expression in depression [26-30], for instance 115% increase in GluN2A in the amygdala [30] and 50% reduction of GluN2A and B in the PFC [26]. These results are striking given the prevalence and importance of the NMDAR to basic cognition.

In summary, the monoamine hypothesis has been an extremely important step in the evolution of our understanding of mood disorders, although our complacence and attachment to it has perhaps closed many minds. However some new depression hypotheses have emerged over the past decade, all of which broaden and deepen our understanding of mood disorders. These include the neurotrophic hypothesis (circa 2000>) [18,31], the inflammatory hypothesis (circa 2005>) [11,32], and most recently glutamate/NMDA hypotheses of depression (circa 2005>) [19,21,33].

References

[1] J.R. Lacasse, J. Leo, Serotonin and depression: a disconnect between the advertisements and the scientific literature., PLoS Medicine. 2 (2005) e392.

[2] G.R. Heninger, P.L. Delgado, D.S. Charney, The revised monoamine theory of depression: a modulatory role for monoamines, based on new findings from monoamine depletion experiments in humans., Pharmacopsychiatry. 29 (1996) 2-11.

[3] T. Klaassen, W.J. Riedel, N.E.P. Deutz, H.M. Van Praag, Mood congruent memory bias induced by tryptophan depletion., Psychological Medicine. 32 (2002) 167-72.

[4] E.A.T. Evers, F.M. van der Veen, J.A. van Deursen, J.A.J. Schmitt, N.E.P. Deutz, J. Jolles, The effect of acute tryptophan depletion on the BOLD response during performance monitoring and response inhibition in healthy male volunteers., Psychopharmacology. 187 (2006) 200-8.

[5] E.A.T. Evers, A. Sambeth, J.G. Ramaekers, W.J. Riedel, F.M. van der Veen, The effects of acute tryptophan depletion on brain activation during cognition and emotional processing in healthy volunteers., Current Pharmaceutical Design. 16 (2010) 1998-2011.

[6] E.A.T. Evers, F.M. van der Veen, D. Fekkes, J. Jolles, Serotonin and cognitive flexibility: neuroimaging studies into the effect of acute tryptophan depletion in healthy volunteers., Current Medicinal Chemistry. 14 (2007) 2989-95.

[7] S. Leu-Semenescu, I. Arnulf, C. Decaix, F. Moussa, F. Clot, C. Boniol, et al., Sleep and rhythm consequences of a genetically induced loss of serotonin., Sleep. 33 (2010) 307-14.

[8] J.H. Meyer, A.A. Wilson, S. Sagrati, L. Miler, P. Rusjan, P.M. Bloomfield, et al., Brain monoamine oxidase A binding in major depressive disorder: relationship to selective serotonin reuptake inhibitor treatment, recovery, and recurrence., Archives of General Psychiatry. 66 (2009) 1304-12.

[9] J. Sacher, A.A. Wilson, S. Houle, P. Rusjan, S. Hassan, P.M. Bloomfield, et al., Elevated brain monoamine oxidase A binding in the early postpartum period., Archives of General Psychiatry. 67 (2010) 468-74.

[10] J.H. Meyer, N. Ginovart, A. Boovariwala, S. Sagrati, D. Hussey, A. Garcia, et al., Elevated monoamine oxidase a levels in the brain: an explanation for the monoamine imbalance of major depression., Archives of General Psychiatry. 63 (2006) 1209-16.

[11] M. Maes, B.E. Leonard, A.M. Myint, M. Kubera, R. Verkerk, The new “5-HT” hypothesis of depression: cell-mediated immune activation induces indoleamine 2,3-dioxygenase, which leads to lower plasma tryptophan and an increased synthesis of detrimental tryptophan catabolites (TRYCATs), both of which contribute to th, Progress in Neuro-psychopharmacology & Biological Psychiatry. (2011).

[12] S. Nikolaus, C. Antke, H.-W. Müller, In vivo imaging of synaptic function in the central nervous system: II. Mental and affective disorders., Behavioural Brain Research. 204 (2009) 32-66.

[13] W.C. Drevets, M.E. Thase, E.L. Moses-Kolko, J. Price, E. Frank, D.J. Kupfer, et al., Serotonin-1A receptor imaging in recurrent depression: replication and literature review., Nuclear Medicine and Biology. 34 (2007) 865-77.

[14] G.N. Pandey, Y. Dwivedi, S.C. Pandey, R.R. Conley, R.C. Roberts, C.A. Tamminga, Protein kinase C in the postmortem brain of teenage suicide victims., Neuroscience Letters. 228 (1997) 111-4.

[15] R.C. Shelton, E. Sanders-Bush, D.H. Manier, D.A. Lewis, Elevated 5-HT 2A receptors in postmortem prefrontal cortex in major depression is associated with reduced activity of protein kinase A., Neuroscience. 158 (2009) 1406-15.

[16] J.W. Richardson-Jones, C.P. Craige, B.P. Guiard, A. Stephen, K.L. Metzger, H.F. Kung, et al., 5-HT1A autoreceptor levels determine vulnerability to stress and response to antidepressants., Neuron. 65 (2010) 40-52.

[17] T. Saijo, A. Takano, T. Suhara, R. Arakawa, M. Okumura, T. Ichimiya, et al., Effect of electroconvulsive therapy on 5-HT1A receptor binding in patients with depression: a PET study with [11C]WAY 100635., The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). 13 (2010) 785-91.

[18] C. Pittenger, R.S. Duman, Stress, depression, and neuroplasticity: a convergence of mechanisms., Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology. 33 (2008) 88-109.

[19] W.N. Marsden, Stressor-induced NMDAR dysfunction as a unifying hypothesis for the aetiology, pathogenesis and comorbidity of clinical depression., Medical Hypotheses. 77 (2011) 508-528.

[20] H.D. Schmidt, M. Banasr, R.S. Duman, Future Antidepressant Targets: Neurotrophic Factors and Related Signaling Cascades., Drug Discovery Today. Therapeutic Strategies. 5 (2008) 151-156.

[21] R. Machado-Vieira, H.K. Manji, C.A. Zarate, The role of the tripartite glutamatergic synapse in the pathophysiology and therapeutics of mood disorders., The Neuroscientist : A Review Journal Bringing Neurobiology, Neurology and Psychiatry. 15 (2009) 525-39.

[22] W.C. Drevets, J.L. Price, M.L. Furey, Brain structural and functional abnormalities in mood disorders: implications for neurocircuitry models of depression, Brain Structure & Function. 213 (2008) 93-118.

[23] G. Rajkowska, J.J. Miguel-Hidalgo, Gliogenesis and glial pathology in depression., CNS & Neurological Disorders Drug Targets. 6 (2007) 219-33.

[24] C.L. Raison, R. Dantzer, K.W. Kelley, M.A. Lawson, B.J. Woolwine, G. Vogt, et al., CSF concentrations of brain tryptophan and kynurenines during immune stimulation with IFN-alpha: relationship to CNS immune responses and depression., Molecular Psychiatry. 15 (2010) 393-403.

[25] J. Steiner, M. Walter, T. Gos, G.J. Guillemin, H.-G. Bernstein, Z. Sarnyai, et al., Severe depression is associated with increased microglial quinolinic acid in subregions of the anterior cingulate gyrus: Evidence for an immune-modulated glutamatergic neurotransmission?, Journal of Neuroinflammation. 8 (2011) 94.

[26] A.M. Feyissa, A. Chandran, C.A. Stockmeier, B. Karolewicz, Reduced levels of NR2A and NR2B subunits of NMDA receptor and PSD-95 in the prefrontal cortex in major depression., Progress in Neuro-psychopharmacology & Biological Psychiatry. 33 (2009) 70-5.

[27] G. Nowak, G.A. Ordway, I.A. Paul, Alterations in the N-methyl-D-aspartate (NMDA) receptor complex in the frontal cortex of suicide victims., Brain Research. 675 (1995) 157-64.

[28] M. Beneyto, J.H. Meador-Woodruff, Lamina-specific abnormalities of NMDA receptor-associated postsynaptic protein transcripts in the prefrontal cortex in schizophrenia and bipolar disorder., Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology. 33 (2008) 2175-86.

[29] B. Karolewicz, C.A. Stockmeier, G.A. Ordway, Elevated levels of the NR2C subunit of the NMDA receptor in the locus coeruleus in depression., Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology. 30 (2005) 1557-67.

[30] B. Karolewicz, K. Szebeni, T. Gilmore, D. Maciag, C.A. Stockmeier, G.A. Ordway, Elevated levels of NR2A and PSD-95 in the lateral amygdala in depression., The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). 12 (2009) 143-53.

[31] L. Santarelli, M. Saxe, C. Gross, A. Surget, F. Battaglia, S. Dulawa, et al., Requirement of hippocampal neurogenesis for the behavioral effects of antidepressants., Science (New York, N.Y.). 301 (2003) 805-9.

[32] M. Maes, The cytokine hypothesis of depression: inflammation, oxidative & nitrosative stress (IO&NS) and leaky gut as new targets for adjunctive treatments in depression., Neuro Endocrinology Letters. 29 (2008) 287-91.

[33] A. Kugaya, G. Sanacora, Beyond monoamines: glutamatergic function in mood disorders., CNS Spectrums. 10 (2005) 808-19.

H2S (hydrogen sulfide) physiology

2011-07-08T11:31:00.000-07:00

H2S (hydrogen sulphide) is typically most well-known as a toxic environmental gas which binds to cytochrome oxidase and inhibits energy metabolism. However H2S is also produced in small amounts in the body where the last 15 years of research have shown that it functions as an important gaseous signalling molecule, alongside the other two currently known gaseous mediators - NO (nitric oxide) and CO (carbon monoxide). However it is also produced in small amounts in the body where the last 15 years of research have shown that it functions as an important gaseous signalling molecule, alongside the other two currently known gaseous mediators - NO (nitric oxide) and CO (carbon monoxide). H2S plays a role in processes such as neurotransmission, inflammation, nociception, insulin release, vasodilation and redox. In general, H2S has many benefits at healthy physiological levels, but becomes harmful at higher levels. Raised H2S levels have been reported in CFS ([1] unpublished) and have been hypothesised to play a role in CFS symptomatology and pathogenesis [2]. Excessive levels of H2S in many with CFS might result from various sources such as: (i) gut-bacterial origin; (ii) endogenous metabolic dysfunction; (iii) excessive endogenous signalling stimulating H2S synthesis/release. Option (i) has been proposed by some, but for it to be of gut-bacterial origin, it seems likely that there would have to be excessive breakdown of sulphur containing foods in the gut, and perhaps a resulting deficiency of sulphur containing amino acids in the blood. Personally I favour options (ii) and (iii). Below is an objective summary of the latest research on the functions of H2S in the body under normal physiological conditions, some of which may bring answers questions about the role of H2S in CFS, whilst some may bring more questions.

H2S metabolism

H2S is produced from cysteine or homocysteine by the P5P-dependant transsulfuration enzymes, CBS (cystathionine beta-synthase) and CGL (cystathionine gamma-lyase, aka CSE), as well as by the enzymes 3MST (3-mercaptopyruvate sulfurtransferase) and CAT (cysteine aminotransferase) and possibly others (e.g. 3MP) [3]. Murine studies have shown that in the liver, CBS is only responsible for 3% of H2S production by the transsulfuration pathway, whereas in the kidney and brain the majority of H2S comes from the CBS reaction [4], the extent of which is dependent upon its allosteric activation by SAMe [5]; notably CBS dominance in the brain is also suggested by higher relative levels of cystathionine in the rodent and primate brain [6]. Production of H2S is likely to be altered under hyperhomocysteinemic conditions where the relative contribution of CBS to H2S formation is likely to decrease and CGL to increase [5]. H2S is released either directly after enzymatic production or from sulfur stores in response to acidic conditions or reducing agents [3]. H2S is metabolised or detoxified mainly through oxidation where it is converted first to sulphite by the enzyme sulfite reductase, then to sulphate by the enzyme sulphite oxidase (molybdenum cofactor), and finally excreted in urine.

H2S Functions

In the body H2S is a smooth muscle relaxant and shares similar vasodilation effects to nitric oxide, although via a different mechanism - activation of KATP channels [7,8]. As such H2S is involved in blood pressure regulation; CGL is expressed in vascular tissue and CGL knockout mice exhibit hypertension [3]. CBS and CGL are also expressed in the penis where H2S is involved in the vasodilation mediating an erection [9]. Studies have shown that H2S acts synergistically with NO to relax vascular smooth muscle; NO stimulates CGL and H2S production, and H2S stimulated vascular relaxation is attenuated by NOS antagonists [3]. Recent research is increasingly showing that H2S modulates both pro-inflammatory [10] and anti-inflammatory pathways [11-14], possibly suggesting cell and situation specific inflammatory modulation. With regards to anti-inflammatory activity, H2S has been shown to attenuate interleukin-1β, 6, 8, and TNF-α, whilst increasing HO-1 and interleukin-10 [11-14].

In the nervous system, H2S production is induced in response to neuronal excitation in a Ca2+/calmodulin-dependent manner; specifically Ca2+ influx through NMDARs induces CBS activity and thus H2S production [15]. H2S selectively enhances NMDAR-mediated responses and facilitates LTP (memory and learning) in the hippocampus [3]. Whilst the other gaseous mediators (NO and CO) also facilitate LTP, and do so by activating the second messenger cGMP, H2S acts directly on NMDARs and presumably in a similar manner to other reducing agents such as DTT and glutathione, which have also been shown to enhance NMDAR activity [16]. H2S also induces Ca2+ waves in astrocytes, which may be mediated by activation of TRP channels [3,17]. H2S is neuro- and cardio-protective via its activation of Cl- and KATP channels which stabilise membrane potentials and protect against excitotoxicity [3]. Finally, H2S has been shown to lower sympathetic tone by reducing noradrenaline and adrenaline release [18].

Research has demonstrated a robust cytoprotective role for H2S via its direct and indirect modulation of redox. In the nervous system H2S boosts neuronal glutathione levels through enhanced cystine and cysteine transport, and also enhanced γ-GCS activity [3,19]. H2S as a reducing agent has also demonstrated direct protective effects against cytosolic and mitochondrial oxidative stress [3], and it has been suggested that H2S may directly scavenge the peroxynitrite radical [20]. Notably brain H2S is severely depressed in Alzheimer’s disease [21], which is consistent with disturbance to most other methylation-related parameters and hypomethylation in Alzheimer’s [22]. Finally H2S-induced cardioprotection was recently demonstrated to be NOS dependant, once again illustrating the synergy between these two gases [23].

Concluding speculation

With regards to illnesses featuring methylation dysfunction and specifically lowered SAMe, one theory based upon the above information may be that lowered SAMe stimulation of CBS activity leads to lowered H2S levels in the kidney and brain, whilst increased homocysteine levels stimulate CGL activity (subject to B6 availability) and H2S levels in the liver and vasculature. This might occur because the CGL enzyme has been shown to be far more responsive to hyperhomocysteine conditions than CBS, and this CGL stimulation by homocysteine leads to up-regulation of H2S producing reactions (upward arrows on diagram) [5]. However increased H2S levels in illnesses such as CFS might also arise from disrupted redox, excessive inflammation and NO production and the resulting stimulation of CGL activity. Given that H2S is generally associated with positive modulation of redox and inflammation, whereas CFS is associated with increased oxidative stress and inflammation, this may support the notion that excessive H2S production results from disturbance of these processes.

References

[1] K. De Meirleir, C. Roelant, M. Fremont, Research on Extremely Disabled M.E. Patients Reveals the True Nature of the Disorder., (2009).

[2] M.D. Lemle, Hypothesis: chronic fatigue syndrome is caused by dysregulation of hydrogen sulfide metabolism., Medical Hypotheses. 72 (2009) 108-9.

[3] H. Kimura, Hydrogen sulfide : its production , release and functions, Amino Acids. (2010).

[4] O. Kabil, V. Vitvitsky, P. Xie, R. Banerjee, The quantitative significance of the transsulfuration enzymes for H2S production in murine tissues., Antioxidants & Redox Signaling. 15 (2011) 363-72.

[5] S. Singh, D. Padovani, R.A. Leslie, T. Chiku, R. Banerjee, Relative contributions of cystathionine beta-synthase and gamma-cystathionase to H2S biogenesis via alternative trans-sulfuration reactions., The Journal of Biological Chemistry. 284 (2009) 22457-66.

[6] V. Vitvitsky, M. Thomas, A. Ghorpade, H.E. Gendelman, R. Banerjee, A functional transsulfuration pathway in the brain links to glutathione homeostasis., The Journal of Biological Chemistry. 281 (2006) 35785-93.

[7] G.S. Dawe, S.P. Han, J.S. Bian, P.K. Moore, Hydrogen sulphide in the hypothalamus causes an ATP-sensitive K+ channel-dependent decrease in blood pressure in freely moving rats., Neuroscience. 152 (2008) 169-77.

[8] G. Tang, L. Wu, R. Wang, Interaction of hydrogen sulfide with ion channels., Clinical and Experimental Pharmacology & Physiology. 37 (2010) 753-63.

[9] R. d’ Emmanuele di Villa Bianca, R. Sorrentino, P. Maffia, V. Mirone, C. Imbimbo, F. Fusco, et al., Hydrogen sulfide as a mediator of human corpus cavernosum smooth-muscle relaxation., Proceedings of the National Academy of Sciences of the United States of America. 106 (2009) 4513-8.

[10] L. Zhi, A.D. Ang, H. Zhang, P.K. Moore, M. Bhatia, Hydrogen sulfide induces the synthesis of proinflammatory cytokines in human monocyte cell line U937 via the ERK-NF-kappaB pathway., Journal of Leukocyte Biology. 81 (2007) 1322-32.

[11] L.-L. Pan, X.-H. Liu, Q.-H. Gong, D. Wu, Y.-Z. Zhu, Hydrogen sulfide attenuated tumor necrosis factor-α-induced inflammatory signaling and dysfunction in vascular endothelial cells., PloS One. 6 (2011) e19766.

[12] A. Esechie, L. Kiss, G. Olah, E.M. Horváth, H. Hawkins, C. Szabo, et al., Protective effect of hydrogen sulfide in a murine model of acute lung injury induced by combined burn and smoke inhalation., Clinical Science (London, England : 1979). 115 (2008) 91-7.

[13] T. Li, B. Zhao, C. Wang, H. Wang, Z. Liu, W. Li, et al., Regulatory effects of hydrogen sulfide on IL-6, IL-8 and IL-10 levels in the plasma and pulmonary tissue of rats with acute lung injury., Experimental Biology and Medicine (Maywood, N.J.). 233 (2008) 1081-7.

[14] K. Kang, H.-chi Jiang, M.-yan Zhao, X.-ying Sun, S.-ha Pan, [Protection of CSE/H2S system in hepatic ischemia reperfusion injury in rats]., Zhonghua Wai Ke Za Zhi [Chinese Journal of Surgery]. 48 (2010) 924-8.

[15] K. Eto, M. Ogasawara, K. Umemura, Y. Nagai, H. Kimura, Hydrogen sulfide is produced in response to neuronal excitation., The Journal of Neuroscience : The Official Journal of the Society for Neuroscience. 22 (2002) 3386-91.

[16] K. Bodhinathan, A. Kumar, T.C. Foster, Intracellular redox state alters NMDA receptor response during aging through Ca2+/calmodulin-dependent protein kinase II., The Journal of Neuroscience : The Official Journal of the Society for Neuroscience. 30 (2010) 1914-24.

[17] Y. Nagai, M. Tsugane, J.-I. Oka, H. Kimura, Hydrogen sulfide induces calcium waves in astrocytes., The FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology. 18 (2004) 557-9.

[18] K.H. Kulkarni, E.M. Monjok, R. Zeyssig, G. Kouamou, O.N. Bongmba, C.A. Opere, et al., Effect of hydrogen sulfide on sympathetic neurotransmission and catecholamine levels in isolated porcine iris-ciliary body., Neurochemical Research. 34 (2009) 400-6.

[19] Y. Kimura, Y.-I. Goto, H. Kimura, Hydrogen sulfide increases glutathione production and suppresses oxidative stress in mitochondria., Antioxidants & Redox Signaling. 12 (2010) 1-13.

[20] M. Whiteman, J.S. Armstrong, S.H. Chu, S. Jia-Ling, B.-S. Wong, N.S. Cheung, et al., The novel neuromodulator hydrogen sulfide: an endogenous peroxynitrite “scavenger”?, Journal of Neurochemistry. 90 (2004) 765-8.

[21] K. Eto, Brain hydrogen sulfide is severely decreased in Alzheimer’s disease, Biochemical and Biophysical Research Communications. 293 (2002) 1485-1488.

[22] F. Coppedè, One-carbon metabolism and Alzheimer’s disease: focus on epigenetics., Current Genomics. 11 (2010) 246-60.

[23] B. Sojitra, Y. Bulani, U.K. Putcha, A. Kanwal, P. Gupta, M. Kuncha, et al., Nitric oxide synthase inhibition abrogates hydrogen sulfide-induced cardioprotection in mice., Molecular and Cellular Biochemistry. (2011).

Your brain on ATP - Purinergic signalling

2011-05-17T08:55:00.001-07:00

Many illnesses such as CFS (see here) are increasingly associated with mitochondrial dysfunction as a major part of their pathophysiology. The consequences of such energy dysfunction are usually considered with reference to ATP's is fundamental role in basic cellular metabolism; however, usually neglected but also important is ATP's role as a signalling molecule. Purinergic signalling occurs ubiquitously in the body, although I will describe below its basic effects in the nervous system, and specifically with regards to ATP and the brain.

ATP in the nervous system

ATP is involved in most aspects of neuron and glia metabolism, most notably the maintenance of transmembrane ion gradients (e.g. Na+/k+-ATPase & Ca2+-ATPase), cAMP formation, kinase-mediated phosphorylation, vesicle loading (V-ATPase), and glutamate metabolism (glutamine synthase). At the signalling level, ATP and its derivatives (ADP, AMP & adenosine) also function as fast co-transmitters throughout the entire nervous system, via activation of various purinergic receptors located on neurons and glia [1,2].

ATP signalling

ATP (adenosine triphosphate) is a nucleotide which consists of three phosphate groups bound to adenosine. Simply put, chemical energy is released by hydrolysis of ATP and resulting phosphate release; at various rates of energy usage ATP can be sequentially degraded from ATP to ADP to AMP and finally adenosine. Each of these molecules can activate different signalling pathways, hence the relative balance of ATP and its derivative metabolites directly influences cell activity and energy homeostasis. Signalling pathways activated by ATP and its derivatives include the AMPK cascade and the purinergic receptors, which consist of P1 (adenosine receptors), P2X and P2Y receptors. In the brain, generally ATP acts to enhance neuronal activity, whereas adenosine acts to inhibit neuronal activity, and in so doing acts as a homeostatic feedback regulator of energy consumption. In healthy individuals, periods of increased energy consumption lower the ATP:AMP ratio and ultimately promote extracellular adenosine and lactate accumulation, mostly in basel forebrain and cortical areas [3,4]. Adenosine activates the A1 receptor and AMPK, which inhibit neuronal activity (via pre- and postsynaptic mechanisms), and during prolonged wakefulness or sleep deprivation, basel forebrain adenosine accumulation promotes sleep [3,4]. Sleep has been observed to induce a surge in ATP levels during the first few hours [5]. The lactate which accompanies adensosine accumulation during neuronal energy consumption is in accordance with a major role of lactate as a glucose-derived energy substrate in the nervous system, as described by the 'astrocyte-neuron lactate shuttle' model [Pellerin and Magistretti]. However it has been observed that with age there is no concomitant increase in lactate with adenosine accumulation, which may be due to inefficient energy metabolism [4] (i.e. glycolysis).

Adenosine is widely accepted to be a major inhibitory neuromodulator second only to gaba [6]. Furthermore, the neuronal inhibition promoted by accumulation of ATP derivatives such as AMP and adenosine, likely represents the fundamental neuroprotective mechanism against low ATP-induced excitotoxicity in the nervous system [6,7]. The adenosine system also represents another pharmacological target being considered for several neurological disorders; notably caffeine's major mechanism of action in the body is by strong unselective antagonism of adenosine receptors [8,9].

ATP & Brain fog

A common part of the CFS experience and that of other neurological illnesses is ‘brain fog’, which is characterised by difficultly thinking clearly (i.e. difficulty processing, storing and retrieving information). Whilst there may be many mechanisms mediating the expression of brain fog, I personally think one major common mechanism is likely to be disrupted purinergic signalling, due to low ATP levels. This may be of particular relevance to the increasing brain fog experienced with increasing energy expenditure, as a patient goes out of their ‘energy envelope’. In these situations, ATP shortage would promote accumulation of the inhibitory ATP derivatives: AMP and adenosine; which would promote cognitive suppression in accordance with the energy-sleep model [3,4,10,11]. I think brain adenosine accumulation may well accompany the already reported lactate increases in CFS [12,13] and also correlate symptoms of brain fog. Notably, the association of CFS with raised CSF lactate probably suggests energy malfunction in CAC (citric acid cycle) and ETC (electron transport chain), which contrasts the age-related energy deficits implied above.

References

[1] G. Burnstock, Purinergic cotransmission., Experimental Physiology. 94 (2009) 20-4.

[2] B.S. Khakh, G. Burnstock, The double life of ATP., Scientific American. 301 (2009) 84-90, 92.

[3] T. Porkka-Heiskanen, A.V. Kalinchuk, Adenosine, energy metabolism and sleep homeostasis., Sleep Medicine Reviews. (2010).

[4] H.-K. Wigren, K.-M. Rytkönen, T. Porkka-Heiskanen, Basal forebrain lactate release and promotion of cortical arousal during prolonged waking is attenuated in aging., The Journal Of Neuroscience : The Official Journal Of the Society For Neuroscience. 29 (2009) 11698-707.

[5] M. Dworak, R.W. McCarley, T. Kim, A.V. Kalinchuk, R. Basheer, Sleep and Brain Energy Levels: ATP Changes during Sleep., The Journal Of Neuroscience : The Official Journal Of the Society For Neuroscience. 30 (2010) 9007-16.

[6] J. Deckert, C.H. Gleiter, Adenosine--an endogenous neuroprotective metabolite and neuromodulator., Journal Of Neural Transmission. Supplementum. 43 (1994) 23-31.

[7] P. Saransaari, S.S. Oja, Mechanisms of Inhibitory Amino Acid Release in the Brain Stem Under Normal and Ischemic Conditions., Neurochemical Research. 35 (2010) 1948-56.

[8] J.A. Ribeiro, A.M. Sebastião, Caffeine and adenosine., Journal Of Alzheimerʼs Disease : JAD. 20 Suppl 1 (2010) S3-15.

[9] A. Rahman, The role of adenosine in Alzheimerʼs disease., Current Neuropharmacology. 7 (2009) 207-16.

[10] P.G. Haydon, G. Carmignoto, Astrocyte control of synaptic transmission and neurovascular coupling., Physiological Reviews. 86 (2006) 1009-31.

[11] M.M. Halassa, P.G. Haydon, Integrated brain circuits: astrocytic networks modulate neuronal activity and behavior., Annual Review Of Physiology. 72 (2010) 335-55.

[12] Ventricular cerebrospinal fluid lactate is increased in chronic fatigue syndrome compared with generalized anxiety disorder: an in vivo 3.0 T (1)H MRS imaging study.

[13] Increased ventricular lactate in chronic fatigue syndrome measured by 1H MRS imaging at 3.0 T. II: comparison with major depressive disorder.

Evidence for bioenergetic dysfunction in CFS

2011-05-17T08:05:00.000-07:00

The central symptom in CFS is fatigue, yet the origin (psychological, sensory/neural, or cellular/mitochondrial) of this fatigue is still disputed. Several studies have shown direct evidence of cellular bioenergetic dysfunction in CFS, as measured in vivo (via MRS) in skeletal muscle and cardiac tissue [1-6], as well as in neutrophils [7]. These studies typically show early acidosis, oxidative stress, and ATP depletion in response to exercise; with one study highlighting the co-association of skeletal muscle and cardiac bioenergetic abnormalities in CFS [3]. A recent study further suggested that the decrease in mitochondrial ATP synthesis in CFS/ME patients is not caused by a defect in the enzyme complexes catalysing oxidative phosphorylation, but in another factor [2]. A couple more recent studies have also shown increased CSF (cerebral spinal fluid) lactate in CFS relative to controls and patients with GAD (general anxiety) and MDD (major depression) [8,9]. This increased lactate correlated with symptoms of fatigue, and likely reflects compromised mitochondrial metabolism in the brain in CFS.

There is also indirect evidence of mitochondrial dysfunction in CFS. Several studies have reported lowered l-carnitine levels which parallel fatigue [10-14] and lowered acetyl-carnitine brain uptake [15], whilst others have failed to find any changes [16,17]; furthermore carnitine supplementation improves fatigue in CFS patients [18,19]. Mitochondrial abnormalities and mutations to mtDNA have been reported in CFS [20,21], whilst another study found no physical changes to mitochondria [22]. Low serum Co-Q10 levels have been reported in CFS which correlates with illness severity [23,24]. Magnesium deficiency has also been reported in CFS [24,25]. Treatment with NADH has been found to be beneficial in a couple of studies [26,27], whilst ineffective in another [28]. D-ribose supplementation has also been shown to significantly alleviate fatigue in CFS patients [29]. Changes to the make-up of the mitochondrial membrane are also implicated in CFS [30,31]; notably, treatment aimed at restoring cellular and mitochondrial membranes significantly improves symptoms and energy metabolism in CFS patients [31].

References

[1] R. Wong, G. Lopaschuk, G. Zhu, D. Walker, D. Catellier, D. Burton, et al., Skeletal muscle metabolism in the chronic fatigue syndrome. In vivo assessment by 31P nuclear magnetic resonance spectroscopy., Chest. 102 (1992) 1716-22.

[2] R.C.W. Vermeulen, R.M. Kurk, F.C. Visser, W. Sluiter, H.R. Scholte, Patients with chronic fatigue syndrome performed worse than controls in a controlled repeated exercise study despite a normal oxidative phosphorylation capacity., Journal Of Translational Medicine. 8 (2010) 93.

[3] K.G. Hollingsworth, D.E.J. Jones, R. Taylor, A.M. Blamire, J.L. Newton, Impaired cardiovascular response to standing in chronic fatigue syndrome., European Journal Of Clinical Investigation. 40 (2010) 608-15.

[4] R.J. Lane, M.C. Barrett, D.J. Taylor, G.J. Kemp, R. Lodi, Heterogeneity in chronic fatigue syndrome: evidence from magnetic resonance spectroscopy of muscle., Neuromuscular Disorders : NMD. 8 (1998) 204-9.

[5] K.K. McCully, B.H. Natelson, S. Iotti, S. Sisto, J.S. Leigh, Reduced oxidative muscle metabolism in chronic fatigue syndrome., Muscle & Nerve. 19 (1996) 621-5.

[6] Y. Jammes, J.G. Steinberg, O. Mambrini, F. Brégeon, S. Delliaux, Chronic fatigue syndrome: assessment of increased oxidative stress and altered muscle excitability in response to incremental exercise., Journal Of Internal Medicine. 257 (2005) 299-310.

[7] S. Myhill, N.E. Booth, J. McLaren-Howard, Chronic fatigue syndrome and mitochondrial dysfunction., International Journal Of Clinical and Experimental Medicine. 2 (2009) 1-16.

[8] S.J. Mathew, X. Mao, K.A. Keegan, S.M. Levine, E.L.P. Smith, L.A. Heier, et al., Ventricular cerebrospinal fluid lactate is increased in chronic fatigue syndrome compared with generalized anxiety disorder: an in vivo 3.0 T (1)H MRS imaging study., NMR In Biomedicine. 22 (2009) 251-8.

[9] J.W. Murrough, X. Mao, K.A. Collins, C. Kelly, G. Andrade, P. Nestadt, et al., Increased ventricular lactate in chronic fatigue syndrome measured by 1H MRS imaging at 3.0 T. II: comparison with major depressive disorder., NMR In Biomedicine. 23 (2010) 643-50.

[10] H. Kuratsune, K. Yamaguti, M. Takahashi, H. Misaki, S. Tagawa, T. Kitani, Acylcarnitine deficiency in chronic fatigue syndrome., Clinical Infectious Diseases : An Official Publication Of the Infectious Diseases Society Of America. 18 Suppl 1 (1994) S62-7.

[11] A.V. Plioplys, S. Plioplys, Serum levels of carnitine in chronic fatigue syndrome: clinical correlates., Neuropsychobiology. 32 (1995) 132-8.

[12] S.E. Reuter, A.M. Evans, Long-chain acylcarnitine deficiency in patients with chronic fatigue syndrome. Potential involvement of altered carnitine palmitoyltransferase-I activity., Journal Of Internal Medicine. (2010).

[13] Y.-J. Li, D.-X. Wang, X.-L. Bai, J. Chen, Z.-D. Liu, Z.-J. Feng, et al., [Clinical characteristics of patients with chronic fatigue syndrome: analysis of 82 cases]., Zhonghua Yi Xue Za Zhi. 85 (2005) 701-4.

[14] H. Kuratsune, K. Yamaguti, G. Lindh, B. Evengard, M. Takahashi, T. Machii, et al., Low levels of serum acylcarnitine in chronic fatigue syndrome and chronic hepatitis type C, but not seen in other diseases., International Journal Of Molecular Medicine. 2 (1998) 51-6.

[15] T. Okada, M. Tanaka, H. Kuratsune, Y. Watanabe, N. Sadato, Mechanisms underlying fatigue: a voxel-based morphometric study of chronic fatigue syndrome., BMC Neurology. 4 (2004) 14.

[16] M.G. Jones, C.S. Goodwin, S. Amjad, R.A. Chalmers, Plasma and urinary carnitine and acylcarnitines in chronic fatigue syndrome., Clinica Chimica acta; International Journal Of Clinical Chemistry. 360 (2005) 173-7.

[17] P.M. Soetekouw, R.A. Wevers, P. Vreken, L.D. Elving, A.J. Janssen, Y. van der Veen, et al., Normal carnitine levels in patients with chronic fatigue syndrome., The Netherlands Journal Of Medicine. 57 (2000) 20-4.

[18] R.C.W. Vermeulen, H.R. Scholte, Exploratory open label, randomized study of acetyl- and propionylcarnitine in chronic fatigue syndrome., Psychosomatic Medicine. 66 (n.d.) 276-82.

[19] A.V. Plioplys, S. Plioplys, Amantadine and L-carnitine treatment of Chronic Fatigue Syndrome., Neuropsychobiology. 35 (1997) 16-23.

[20] L. Vecchiet, G. Montanari, E. Pizzigallo, S. Iezzi, P. de Bigontina, L. Dragani, et al., Sensory characterization of somatic parietal tissues in humans with chronic fatigue syndrome., Neuroscience Letters. 208 (1996) 117-20.

[21] C. Zhang, A. Baumer, I.R. Mackay, A.W. Linnane, P. Nagley, Unusual pattern of mitochondrial DNA deletions in skeletal muscle of an adult human with chronic fatigue syndrome., Human Molecular Genetics. 4 (1995) 751-4.

[22] A.V. Plioplys, S. Plioplys, Electron-microscopic investigation of muscle mitochondria in chronic fatigue syndrome., Neuropsychobiology. 32 (1995) 175-81.

[23] M. Maes, I. Mihaylova, M. Kubera, M. Uytterhoeven, N. Vrydags, E. Bosmans, Coenzyme Q10 deficiency in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is related to fatigue, autonomic and neurocognitive symptoms and is another risk factor explaining the early mortality in ME/CFS due to cardiovascular disorder., Neuro Endocrinology Letters. 30 (2009) 470-6.

[24] R.K. Kurup, P.A. Kurup, Hypothalamic digoxin, cerebral chemical dominance and myalgic encephalomyelitis., The International Journal Of Neuroscience. 113 (2003) 683-701.

[25] B. Manuel y Keenoy, G. Moorkens, J. Vertommen, M. Noe, J. Nève, I. De Leeuw, Magnesium status and parameters of the oxidant-antioxidant balance in patients with chronic fatigue: effects of supplementation with magnesium., Journal Of the American College Of Nutrition. 19 (2000) 374-82.

[26] M.L. Santaella, I. Font, O.M. Disdier, Comparison of oral nicotinamide adenine dinucleotide (NADH) versus conventional therapy for chronic fatigue syndrome., Puerto Rico Health Sciences Journal. 23 (2004) 89-93.

[27] L.M. Forsyth, H.G. Preuss, A.L. MacDowell, L. Chiazze, G.D. Birkmayer, J.A. Bellanti, Therapeutic effects of oral NADH on the symptoms of patients with chronic fatigue syndrome., Annals Of allergy, asthma & Immunology : Official Publication Of the American College Of Allergy, Asthma, & Immunology. 82 (1999) 185-91.

[28] J. Alegre, J.M. Rosés, C. Javierre, A. Ruiz-Baqués, M.J. Segundo, T.F. de Sevilla, [Nicotinamide adenine dinucleotide (NADH) in patients with chronic fatigue syndrome]., Revista Clínica Española. 210 (2010) 284-8.

[29] J.E. Teitelbaum, C. Johnson, J. St Cyr, The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study., Journal Of alternative and Complementary Medicine (New York, N.Y.). 12 (2006) 857-62.

[30] Y. Hokama, C.E. Campora, C. Hara, T. Kuribayashi, D. Le Huynh, K. Yabusaki, Anticardiolipin antibodies in the sera of patients with diagnosed chronic fatigue syndrome., Journal Of Clinical Laboratory Analysis. 23 (2009) 210-2.

[31] G.L. Nicolson, R. Ellithorpe, Lipid Replacement and Antioxidant Nutritional Therapy for Restoring Mitochondrial Function and Reducing Fatigue in Chronic Fatigue Syndrome and other Fatiguing Illnesses, Journal Of Chronic Fatigue Syndrome. (2006).

Magnesium deficiency & neurological function

2011-04-25T09:33:00.001-07:00

[This article is taken from my recent NMDAR paper.]

Introduction

The western diet is relatively deficient in magnesium, with the majority of Americans not achieving the RDA and/or consuming altered dietary Mg/Ca ratios [255,256]. Magnesium deficiency has links with many conditions such as mood disorders, tourette’s, insulin resistance, cardiovascular disease and neurodegenerative disorders [257-261]. Magnesium deficiency has also recently been linked to the aging process itself, since studies have shown that culture in low magnesium accelerates the senescence of human cells [262]. Owing to magnesium’s importance in the nervous system, magnesium deficiency can reduce seizure threshold and induce epileptiform activity, and as such is often used as an animal epilepsy model [263-265]. Animal models have also shown that magnesium deficiency induces depression which is reversed by SSRIs [260,266]. A PMRS study reported low brain intracellular magnesium levels in MDD [218]. Magnesium supplementation has demonstrated anxiolytic and antidepressant activity in animal models [260], and rapid antidepressant activity in human TRD (treatment-resistant depression) [267]. Magnesium supplementation has also been shown to facilitate learning and improve other symptoms in human dementia [268]; and in rats elevating brain magnesium leads to the enhancement of learning abilities, working memory, and short and long-term memory [269].

Magnesium biology
Magnesium (Mg2+) is the second most abundant intracellular cation after potassium [257], and is fundamental to basic cellular metabolism. Magnesium is involved in hundreds of enzymatic reactions which participate in the metabolism of glucose, lipids, proteins, nucleic acids and DNA [257]. In such reactions magnesium participates either by direct binding and allosteric activation, or as a magnesium-nucleotide complex (e.g. mgATP). As such magnesium is particularly involved in all reactions using nucleotides as cofactors or substrates, including hydrolases and phosphotransferases, such as ATPases and protein kinases [258]. In such reactions, enzyme activity depends both on the ratio and absolute levels of Mg2+ and ATP [257]. At the membrane level, magnesium is known to alter both receptor sites and transmembrane ion movements; magnesium forms complexes with phospholipids, which reduces their fluidity and permeability [257]. Within the cell, magnesium is required for ATP and DNA synthesis, and evidence suggests magnesium is directly correlated to cellular proliferation [262].

NMDAR blocker
At the neurotransmission level, magnesium is vital for the NMDAR’s characteristic slow activation kinetics and co-incident detection [270]. At membrane potentials below -40mv, Mg2+ ions bind to the NMDAR channel pore and block permeability, whereas during depolarisation Mg2+ dissociates allowing the NMDAR ion channel to open [121,271]. The subunit composition of NMDARs determines the strength of Mg2+ blocking; NMDARs containing GluN2A/B subunits are similarly and most strongly blocked by Mg2+, whilst GluN2C/D containing NMDARs convey much weaker Mg2+ blocking [272], and GluN3 containing NMDARs have low Mg2+ blocking and low Ca2+ permeability [271]. Therefore the Mg2+ block may be most active on presynaptic, postsynaptic and extrasynaptic neuronal NMDARs, where GluN2A/B subunits are most prevalent. Magnesium also affects the affinity of NMDAR ligands, such as increasing glycine’s affinity for the NMDAR which potentiates NMDAR activity at positive membrane potentials [273,274], and increasing glutamate’s dissociation and so enhancing NMDAR desensitisation [270,275]. Magnesium (and ATP) also stimulates the serine racemase enzyme [276,277], which converts l-serine to d-serine – an astrocyte derived co-activator of NMDARs. Magnesium’s overall effects on NMDAR activity seem similar to that of ATP [278], in that both shift the glutamate-NMDAR response curve to the right and so ultimately act to increase the signal-to-noise ratio. Deficiency of magnesium leads to NMDAR hypersensitivity and tonic over-activation by increasing channel opening probability [279-281]; such dysfunction impairs synaptic plasticity in the hippocampus [194], and fear conditioning in mice [282,283]. Magnesium-induced NMDAR over-activation has also been shown to cause release of neuronal reduced glutathione which eventually leads to oxidative neuronal death [280]. In the spinal cord, magnesium deficiency induces a sensitisation of nociceptive pathways (pain pathways) which is reversed by NMDAR, PKC or NOS antagonists [281].

Other receptor-level effects
Animal studies have connected magnesium’s neurotransmission-level activity to various other systems, such as monoaminergic and cholinergic systems [266,284,285]. Magnesium has also been shown to increase GABAA activity [286] and 5-HT1A receptor binding [287] - two important inhibitory receptors that mediate anxiolytic and antidepressant activity. Magnesium is also likely to affect the activity of multiple protein kinases and thus intracellular transduction cascades, which will contribute to its memory enhancing effects in humans and animals [268,269].

Magnesium also modulates the stress response and circadian rhythm in humans. Magnesium has been shown to lower ACTH, cortisol and catecholamines [288-290]. Magnesium stimulates n-acetyltransferase activity [291], the penultimate enzyme in melatonin synthesis; as such magnesium deficiency has been shown to lower plasma melatonin in rats [291]. Additionally, the product of the n-acetyltransferase reaction (n-acetyl-serotonin) also acts as a potent Trkb receptor agonist, and in similar fashion to BDNF has been shown to have strong antidepressant and neuroprotective activity [292]. In summary, magnesium’s influence on neuronal activity may be thought of as calming and stabilising, whilst acting to increase the efficiency of signal transduction and synaptic plasticity.

The tripartite synapse & NMDA receptor signalling: glutamate & excitotoxicity in chronic illnesses

2011-04-22T08:12:00.000-07:00

Dysfunction of glutamate neurotransmission is thought by many to accompany chronic illnesses featuring a neurological component, most notably neurodegenerative conditions. Glutamatergic dysfunction is also associated with mood disorders, and a few knowledgeable CFS researchers and MDs feel it accompanies the CFS pathophysiology too. It’s usually the NMDA receptor which people consider the problem, and particularly in relation to excitotoxicity. I have been researching this area a lot over the past months, below is my diagram showing the tripartite synapse and synaptic NMDAR signalling, as well as a brief overview of some important points. In particular, this system is more complex and dynamic than some people give it credit for.

Introduction

There are two major brain cell types: neurons and glia (or glial cells). Messages are relayed between these cell types via neurotransmitters diffusing synapses and activating specific receptors on cell membranes (e.g. like a key fitting a lock). On neurons, signals are relayed electrophysically and chemically, whilst on glia receptor activation stimulates chemical pathways, and often leads to Ca2+ mobilisation. The major two neurotransmitters in the nervous system are the amino acids glutamate and gaba, which mediate excitatory and inhibitory neurotransmission respectively. Other neurotransmitters, such as the monoamines (serotonin, noradrenaline and dopamine) usually have a more modulatory effect on synaptic activity. Perhaps more so than any in other organ, brain cells are highly dynamic in terms of their receptor expression and physical structure, a property which has led to the metaphorical 'plastic' description of the brain. This molecular and cellular dynamism and ability to change in response to the external environment is what belies the processes of learning and memory.

The tripartite synapse & glutamate metabolism

The tripartite (three-part) synapse includes the presynaptic neuron, postsynaptic neuron and neighbouring glia, all of which are involved in normal neurotransmission. Glutamate is released in response to an action potential (neuronal impulse), it then binds to and activates various glutamate receptors (AMPAR, NMDAR, mGluR & Kainate) after which it is taken up into glia (normally astrocytes) and processed back to glutamine which can be resupplied to neurons. All glutamate receptors are expressed on all parts of the tripartite synapse (neurons and glia). On neurons AMPARs mediate most of the fast excitatory neurotransmission in the nervous system, NMDARs are generally required for synaptic modification (plasticity), mGluRs are coupled to G-proteins which modulate synaptic activity and intracellular pathways, and finally Kainate receptors play a subtle role in synaptic activity and plasticity. On astrocytes, glutamate receptor activation can lead to the release of gliotransmitters (release of transmitters from glia) which further modulate neuronal activity.

NMDA receptors (NMDARs)

NMDARs of differing biophysical properties are present on neurons, glia and myelin, as well as on immune cells and others in the body. On neurons, NMDARs play a major role in short and long-term neuronal plasticity (the molecular correlate to memory and learning); i.e. they determine whether a synapse and dendrite network get stronger or weaker. At resting potentials, NMDARs (on neurons only) are subject to an open-channel block by magnesium ions, which reside at a site within the pore. This block is crucial for the NMDAR's coincident detection properties and hence its role in hebbian plasticity. For activation NMDARs require co-binding of glutamate and glycine/d-serine, as well as sufficient membrane depolarisation to remove the voltage-dependant magnesium block; which may be achieved by repeated AMPAR activation and the resulting summation of EPSPs (excitatory postsynaptic potentials). Basically the NMDAR detects when their is lots of synaptic activity by only activating with such activity, its activation then creates a lasting change which 'memorises' previous synaptic activity (as discussed below).

NMDAR activation allows intracellular Ca2+ and Na+ influx which activates various signal transduction and gene transcription pathways. Synaptic NMDARs are generally associated with neuronal efficiency cascades and are required for LTP (long-term potentiation) induction; where synaptic currents are strengthened (or potentiated) by trafficking more AMPARs to the synapse. NMDARs are also present at extrasynatic locations (on dendrite shafts and stalks) where they couple to neuronal inefficiency cascades (CREB & ERK1/2 shut-off, etc...). Extrasynaptic NMDARs become activated due to synaptic glutamate spill-over and gliotransmitter release, and may be important for glia modulation of neuronal synchronicity and a form of broad LTD (long-term depression); where synaptic currents are weakened by removing receptors from the synaptic membrane. However, under pathological situations extrasynaptic NMDARs are entirely responsible for mediating NMDAR-dependent excitotoxicity (neuron death resulting from excessive excitatory receptor activation).

Excitotoxicity

Excitotoxicity is usually associated with excessive NMDAR activity on neurons, although the same process can similarly induce toxicity on glia; additionally, some AMPARs are Ca2+ permeable (due to lack of the GluA2 subunit) and can also induce excitotoxicity. As mentioned above, on neurons NMDAR-dependent excitotoxicity is now known to only occur as a consequence of excessive extrasynaptic NMDAR activation [Hardingham & Bading]. This is illustrated nicely by the fact that excessive synaptic NMDAR stimulation actually protects against future excitotoxicity by induction of neuroprotective signal transduction and gene transcription cascades. If however during stimulation there is large glutamate spill over to extrasynaptic locations, then extrasynaptic NMDARs will overpower synaptic NMDARs and induce neuronal inefficiency pathways and potentially excitotoxicity; a situation thought to occur during ischemia (stroke). However the situation is not as simple regarding the tonic (continuous) over-activation thought to occur during some neurodegenerative conditions, and also thought by some to occur in CFS. The reason being, extrasynaptic NMDAR activation is self-protecting under physiological conditions, since it induces a form of broad LTD, mediated via synaptic and extrasynaptic AMPAR and NMDAR internalisation [Li et al, 2010]. This process is also paralleled by neuroplastic changes, such as dendrite retraction. In other words neurons are highly dynamic, both at the receptor and structural level, and moderate extrasynaptic NMDAR activation actually lowers the potential consequences of future NMDAR activation. There's also the potential that extrasynaptic NMDAR activation induces a form heterosynaptic LTD (i.e. induces LTD of adjacent surrounding synapses too), although im not sure about this yet.

CFS/ME

Excessive excitatory activity may be implicated in a proportion of CFS patients, due to the fact that anxiety is commonly co-morbid with CFS, and that many CFS patients feel better on neuro-inhibitory substances such as serotonergic and gabaergic drugs (e.g. SSRIs, SNRIs, etc). Furthermore, some people have also suggested the reduced grey matter reported in the brain of CFS patients may be due to neuronal loss, perhaps from excitotoxicity or reduced neurogenesis (new neuron growth). However, a grey matter reduction could also be due to glia loss or neuropil loss. Neuropil makes up the majority of the grey matter in the brain, and consists of dendrite and glia processes (e.g. astrocyte end feet). Notably, a recent MRI study found raised lactate, but no alterations in gaba and glx (combined measure of glutamate + glutamine) in CFS [Murrough et al, 2010]. This is in contrast to MDD (major depressive disorder), where lowered grey matter corresponds with loss of glia and low glx levels (glx mainly represents intracellular stores). In CFS then, there may be no gross loss of brain cells and glx, but instead neuropil, perhaps caused directly by low ATP or indirectly via tonic extrasynaptic NMDAR over-activation. Excessive NMDAR activity may be achieved by any of the factors below, but lowered ATP will be particularly important in CFS. However the body has a major protective mechanism countering the potentially neurotoxic effects of low ATP in the CNS: low ATP promotes adenosine accumulation which provides a strong neuro-inhibitory force via activation of the A1 receptor.

Aetiology of NMDAR dysfunction

Below are some major factors/stressors i think may be responsible for excessive NMDAR activity in chronic illnesses, with their basic mechanisms:

Neuro-inflammation - triggers gliotransmitter release (TNF-a), quinolinic acid formation, and glia iNOS induction with consequent disruption to energy metabolism.
Magnesium deficiency - removes the voltage-dependent block on NMDARs; zinc deficiency may also be important here too.
ATP deficiency - disrupts transmembrane ion gradients and depolarises neurons; thus disturbs glia glutamate uptake and removes the voltage-dependent block on NMDARs.
Methylation dysfunction & hhcy - promotes amyloid formation, oxidative stress and inflammation, and homocysteine is a major NMDAR stimulator.
Psychological stress - glucocorticoids cause massive glutamate release capable of activating extrasynaptic NMDARs, and can also induce neuro-inflammation.
Oxidative stress - disrupts energy metabolism and increases inflammation; although the direct effect of oxidants is to inhibit the NMDAR.

NMDAR antagonist pharmacology
Promising future drug-based approaches to dealing with excessive extrasynaptic NMDAR activity include memantine and CP101-606 (NMDAR-2B antagonist). Memantine has been shown to preferentially block extrasynaptic NMDARs, whereas CP101-606 blocks the GluN2B subunit which preferentially locates to extrasynaptic locations on mature neurons. Indeed i feel that many other open-channel NMDAR blockers, including magnesium, may preferentially act upon extrasynaptic NMDARs. This is because at extrasynaptic locations NMDARs are exposed to a consistent low-level of ambient glutamate [Haydon & Carmignoto 2006], rendering NMDAR channels more frequently open and accessable to channel blockers.

Folate metabolism - Which form of folate to take?

2010-09-12T05:39:00.000-07:00

Folate (vitamin B9) performs its functions in the body only as various THF (tetrahydrofolate) forms, which are ultimately required for two things:

1. The biosynthesis of nucleotides, which in turn are required for RNA & DNA synthesis (ie. growth);
2. The conversion (remethylation) of homocysteine to methionine, which is required for SAMe synthesis and thus methylation.

One-carbon metabolism
In the body THF essentially acts as a transporter of one-carbon atom groups, such as methenyl (CH), methylene (CH2), methyl (CH3), formyl (CHO), and forminino (CHNH). THF bonds with these one-carbon groups which are released from the metabolism of various amino acids, and then it donates them to reactions which are required for the synthesis of various molecules, such as those involved in RNA and DNA synthesis (pyrimidines and purines), and methlyation (methionine). Folate itself is not used up in these reactions; once THF has donated its ligand (one-carbon group) it is returned to the pool of DHF and THF, where new THF derivatives are formed and the process continues.

B12 and the 'folate trap'
Folate is converted between its various different THF derivatives with the help of many cofactors, such as NAD(P)H, P5P, FAD and B12. Most THF forms are basically interchangeable, that is except for methyl-THF. The conversion of methylene-THF to methyl-THF is not reversible, and the enzyme MS (methionine synthase) is the only acceptor of methyl-THF. MS normally catalyses the reaction between methyl-THF and homocysteine to recycle both back to THF and methionine; this reaction requires methyl-B12 as a cofactor. So a B12 deficiency can cause a 'trapping' of folate as methyl-THF, and thus a deficiency of the other THF derivatives required for DNA synthesis. This is how a B12 deficiency can lead to anemia; i wrote more about the hematological changes that occur in a B12/folate deficiency here.

Folate transport
Most dietary folate is in polyglutamate form which must first be coverted into monoglutamate form (by GGH) before it can be absorbed. Transport of folate into cells is handled by the reduced folate carrier (RFC), and to a lesser extent the folate receptor (FOLR1). Once inside cells the mgATP-dependant enzyme folylpolyglutamate synthetase[19,20] adds glutamate residues to folate (making it a polyglutamate again) which increases its molecular size and prevents cellular loss via folate export pumps.

Which form of folate to take?
Folic acid is still the main form of folate found in supplements and fortified foods. Folic acid (pteroylglutamic acid) is the most basic form of folate, which all other folates are based upon. It does not significantly occour in dietary folate intake, and it must be converted to active THF forms before it can be of any use in the body. DHFR is the enzyme that is responsible for converting inactive folate into active THF forms, and it does this in two reduction reactions which transfer hydrogen atoms from NAD(P)H to folate. Some people might be really bad at running this reaction, for a few reasons:

- DHFR has been demonstrated to have very slow enzyme activity in humans and there is also 5-fold variability[1].
- DHFR can be deactivated by peroxynitrite[2], which might be produced in states of oxidative stress.
- DHFR might also function slowly if there is low availability of NAD(P)H[10].

Furthermore, unmetabolised folic acid in plasma has been associated with lowered NK cell activity[17], and folic acid can compete with active folate uptake at the BBB (blood-brain barrier)[21]. For all these reasons folic acid supplements may not be a reliable way to replete folate metabolism.

Folinic acid (5-formyl-THF) and methyl-THF supplements supply active folate forms directly into folate metabolism. These are natural folate forms that comprise some of our normal dietary folate intake. Methyl-THF also skips the MTHFR reaction, which may be of use to those who have the common C677T snp that slows enzyme activity[4].

Folate and immunity
to come...

Research

1. The extremely slow and variable activity of dihydrofolate reductase in human liver and its implications for high folic acid intake. Steven W. Bailey and June E. Ayling.
2. Peroxynitrite-mediated oxidation of the C85S/C152E mutant of dihydrofolate reductase from Escherichia coli: functional and structural effects.
3. http://bb-cfs.blogspot.com/2010/05/bh4-salvage-pathway.html

4. http://en.wikipedia.org/wiki/MTHFR
5. Laboratory evalulations - Richard S Lord.
6. http://www.genome.jp/kegg/pathway/map/map00670.html
7. Clinical activity of folinic acid in patients with chronic fatigue syndrome.
8. http://www.wikipathways.org/index.php/Pathway:WP241
9. Serum folate and chronic fatigue syndrome.
10. http://bb-cfs.blogspot.com/2010/05/cadmium-toxicity-summary-of-related.html
11. Folate absorption.
12. Intestinal absorption of different types of folate in healthy subjects with an ileostomy.
13. http://en.wikipedia.org/wiki/SLC19A1
14. Folate Deficiency Inhibits the Proliferation of Primary Human CD8+ T Lymphocytes In Vitro.
15. Immunoglobulin deficiency responding to vitamin B12 in two elderly patients with megaloblastic anaemia.
16. Blood Folate Status and Expression of Proteins Involved in Immune Function, Inflammation, and Coagulation: Biochemical and Proteomic Changes in the Plasma of Humans in Response to Long-Term Synthetic Folic Acid Supplementation.
17. Unmetabolized folic acid in plasma is associated with reduced natural killer cell cytotoxicity among postmenopausal women.
18. Reduced folate carrier: biochemistry and molecular biology of the normal and methotrexate-resistant cell.
19. http://www.ebi.ac.uk/interpro/IEntry?ac=IPR001645
20. http://www.genome.jp/dbget-bin/www_bget?ec+6.3.2.17
21. Blood-brain barrier transport of reduced folic acid.
22. The blood-brain barrier and folate deficiency.
23. Brain function in the elderly: role of vitamin b12 and folate.

Redox - Antioxidants vs Free Radicals.

2010-08-24T09:59:00.000-07:00

Introduction.

Free radicals are molecules with an unpaired electron, making them highly reactive; they are formed in animals during normal metabolism and from interactions with various toxins from the environment. Antioxidants and antioxidant enzymes work in the body to neutralise free radicals which would otherwise damage cellular components. Simply put antioxidants are reducing agents that are capable of inhibiting oxidation via electron donation (as a hydrogen atom), and in the process become oxidised themselves.

Most antioxidants can undergo 'redox cycling', that is to say that once oxidised they can be recycled back to their reduced state by other antioxidants or specific enzymes. This is one way antioxidants work together in the body, by exchanging electrons like hot potatoes and simultaneously regenerating one another before finally neutralising the radical.

When free radicals get too high relative to the antioxidants capable of neutralising them, the imbalance allows increased damage to cellular components (e.g. DNA, proteins & lipids). This situation is known as oxidative stress and is a well researched pathological feature of many diseases (including CFS), as well as the aging process itself. Oxidative stress can be caused by increased production of radicals (ROS & RNS) and/or antioxidant deficiency. Radical production can be increased by many things such as toxins, radiation, infections, viruses, nutrient deficiencies, and stress, etc.

Antioxidants

GSH (Reduced glutathione) - Recycles vit E and C; substrate for GPx, GR and GST reactions.

Vitamin C - Recycles GSH, vit E (and BH3).

Vitamin E complex - Scavenges lipid peroxides; recycles vit C.

Co-Q10 (as Ubiquinol) - Recycles vit E and C.

R-lipoic acid*(supplements only) - Recycles vit E, C, Q10, and GSH.

Various flavoniods, carotenoids & phytochemicals - Boost different parts of the antioxidant system.
Cysteine - Rate-limiter for GSH synthesis, and also functions as its own extracellular antioxidant.

Uric acid - Blood plasma antioxidant.

Melatonin - Terminal antioxidant (no redox cycling), directly scavenges many free radicals and protects mitochondria.

Antioxidant enzymes and supporting nutrients

SOD (Superoxide dismutase) - Converts superoxide to O2 and H2O2 (hydrogen peroxide). Zinc, copper and manganese cofactors.

Catalase - Reduces H2O2 to water and O2.

GPx (Glutathione peroxidase) - Scavanges lipid peroxides, and H2O2. Selenium cofactor.
GR (Glutathione reductase) - Recycles GSSG (oxidised glutathione) to GSH. B2 (as FAD) cofactor.

TRXR (Thioredoxin reductase) - Reduces Thioredoxin (which acts as antioxidant). Selenium cofactor.

G6PD (Glucose-6-phosphate dehydrogenase) - Rate-limiting enzyme in the pentose phosphate pathway, responsible for maintaining NAD(P)H pools. NAD(P)H is required for GR reduction of GSSG to GSH, and Thioredoxin reduction.

* Lipoic acid produced by the body dosent normally function as an antioxidant, it is present in the mitochondria where it is enzyme bound and a vital energy cofactor.

Relative antioxidant concentrations

Glutathione (GSH)

Glutathione is the most important cellular and mitochondrial antioxidant, due to its relatively high concentrations and inducible metabolism. It is also essential for detoxification reactions, drug metabolism, immune function and many other metabolic pathways.

Glutathione levels vary throughout the body (0.5-10mmol)[15], with the liver being the main producer and exporter. In the CNS, astrocytes concentrate the highest levels of GSH (up to 8mmol)[19]. Most cellular glutathione is present in the cytoplasm, with about 10% in the mitochondria[15,19]. Glutathione exists in 2 forms: GSH (reduced glutathione) and GSSG (oxidised glutathione). The normal balance in healthy cells is around 10:1 (GSH:GSSG). Since glutathione is the major cellular redox buffer, oxidative stress or cellular toxicity can be evaluated by the balance of GSH to GSSG (reduced to oxidised glutathione)[8,21].

GSH biosynthesis
Glutathione is a tripeptide which is synthesised endogenously from the amino acids cysteine, glycine and glutamate, in 2 ATP-dependant reactions (GCL and GS). GCL is the rate-limiting enzyme and cysteine the rate-limiting amino acid in glutathione synthesis. In the liver, 50% of cysteine comes from dietary methionine (via homocysteine and transsulfuration pathway)[19]. Methylation strongly influences GSH synthesis and redox (reduced-oxidised) balance[20]. Glutathione's antioxidant and detoxification activity comes from the thiol (SH group) in cysteine, which allows hydrogen donation (antioxidant), or xenobiotic conjugation (detoxification).

GSH enzymes

There are a few families of enzymes that use glutathione as a substrate:

- The GPx (glutathione peroxidase) enzymes use GSH to scavenge peroxides (free radicals), in the process converting GSH to GSSG. There are currently 8 known GPx enzymes, each is present in different parts of the body. GPx1 is the most abundant form and is expressed in all cell types. GPx3 is extracellular and in blood serum. GPx4 (aka PHGPx) is the only essential GPx form, and it specifically reduces peroxidised phospholipids and functions as a structural protein[10-14].

- The GST (glutathione s-transferase) family of enzymes use GSH in conjugation reactions to bind and remove toxins such as metals and other xenobiotics. GST activity is strongly activated by the universal methylation molecule, SAMe[20].

- GR (glutathione reductase) utilises NAD(P)H to reduce GSSG (oxidised glutathione) to GSH, and is thus a critical enzyme for maintaining proper redox status.

GSH deficiency
GSH levels are low in most chronic neurological illnesses (e.g. Alzheimer's, Parkinson's and Autism), immune dysfunction illnesses (e.g. CFIDS and HIV), and liver conditions (e.g. ALT, NASH, and Hepatitis). These illnesses are also characterised by increased oxidative stress, and methylation dysfunction.

Decreased GSH can lead to increased oxidative stress, which in the mitochondria can inhibit energy metabolism via inhibition of krebs cycle (e.g. aconitase enzyme) and in particular complex I of the ETC (electron transport chain).

Glutathione can be depleted by various toxins (e.g. metals, mycotoxins, poisions and pesticides), infections, alcohol, smoking, stress, etc. Glutathione deficiency can be caused by various nutritional deficiencies, such as vitamin C[18], magnesium[29-32], methylation vitamins (B12, Folate, B6)[20,25-28], NAD(P)H[33], and amino acids (methionine, cysteine).

Redox (reduction-oxidation)

In biological systems 'redox state' is defined as the balance between reducing agents (antioxidants) and oxidising agents (ROS, or free radicals). The redox state in cells is often accessed via GSH/GSSG balance but can also be evaluated via NAD/NADH or NAD(P)/NAD(P)H and cysteine/cystine balance. Furthermore all these redox balances are not in equilibrium in response to different oxidant and physiological stimuli, so it has been suggested that overall redox state cannot always be accessed by a single entity[6,7].

Biological redox balance also affects redox sensitive pathways via redox signalling. Redox sensitive pathways include various enzymes (such as CBS), inflammatory mediators (such as NF-kB) and apoptosis (cell death) pathways.

Reductive stress

'Reductive stress' is the rare counterpoint to the more prevalent 'oxidative stress', and can occur when the balance of reducing equivalents is too high relative to oxidising equivalents. It has recently been implicated in cardiomyopathy.

Research:

1. The antioxidant miracle. Lester Packer.

2. http://www.thaiwave.com/networkantioxidants/scienceoverview.htm

4. Determination of Blood Total, Reduced, and Oxidized Glutathione in Pediatric Subjects

5. Environmental toxicity, redox signaling and lung inflammation: the role of glutathione.

6. Extracellular redox state: refining the definition of oxidative stress in aging.

7. Redefining oxidative stress.

8. Redox environment of the cell as viewed through the redox state of the glutathione disulfide/glutathione couple.

9. GSSG-mediated Complex I defect in isolated cardiac mitochondria.

10. Biological significance of phospholipid hydroperoxide glutathione peroxidase (PHGPx, GPx4) in mammalian cells.

11. Role for glutathione peroxidase-4 in brain development and neuronal apoptosis: specific induction of enzyme expression in reactive astrocytes following brain injury.

12. Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function.

14. Role for glutathione peroxidase-4 in brain development and neuronal apoptosis: specific induction of enzyme expression in reactive astrocytes following brain injury.

15. Glutathione Metabolism and Its Implications for Health
16. Laboratory evaluations. Richard S Lord.
17. http://en.wikipedia.org/wiki/Glutathione-ascorbate_cycle
18. Vitamin C elevates red blood cell glutathione in healthy adults.
19. Regulation of Neuronal Glutathione Synthesis.
20. http://bb-cfs.blogspot.com/search/label/methylation%20(advanced)
21. Mechanisms of Liver Injury. III. Role of glutathione redox status in liver injury.
22. Role of S-adenosylmethionine, folate, and betaine in the treatment of alcoholic liver disease: summary of a symposium.
23. Specific contribution of methionine and choline in nutritional nonalcoholic steatohepatitis: impact on mitochondrial S-adenosyl-L-methionine and glutathione.
24. Plasma metabolomic profile in nonalcoholic fatty liver disease.
25. Efficacy of methylcobalamin and folinic acid treatment on glutathione redox status in children with autism.
26. Abnormal Transmethylation/transsulfuration Metabolism and DNA Hypomethylation Among Parents of Children with Autism.
27. Metabolic biomarkers of increased oxidative stress and impaired methylation capacity in children with autism.
28. Treatment Study of Methylation Cycle Support in Patients with Chronic Fatigue Syndrome and Fibromyalgia.
29. Enhanced NO production during Mg deficiency and its role in mediating red blood cell glutathione loss.
30. Effects of long-term dietary intake of magnesium on oxidative stress, apoptosis and ageing in rat liver.
31. N-acetylcysteine partially reverses oxidative stress and apoptosis exacerbated by Mg-deficiency culturing conditions in primary cultures of rat and human hepatocytes.
32. Magnesium deprivation decreases cellular reduced glutathione and causes oxidative neuronal death in murine cortical cultures.
33. http://bb-cfs.blogspot.com/2010/05/cadmium-toxicity-summary-of-related.html

Fermentation & (l-d-)lactate production.

2010-08-13T08:38:00.001-07:00

A few research papers show evidence for elevated lactate in CFS[1-3]. Lactate arises from fermentation and can come from endogenus (internal) production or from gut bacteria, but to complicate things there are also two types of lactate: l-lactate and d-lactate. I have described both lactate sources below in some detail, with links into wiki for further info.

Endogenus lactic acid fermentation

Most energy (ATP) in animals comes from aerobic respiration, where glycolysis is used to convert glucose to pyruvate which feeds into krebs cycle which powers oxidative phosphorylation (the latter two of which occur in the mitochondria). But we also use fermentation for energy production, where lactate is constantly produced from and converted to pyruvate by the enzyme LDH. Normal lactate levels remain relatively low and consistent. This is except for when cellular energy demand depletes oxygen, limiting aerobic respirations output, and cells can for short periods rely more upon lactic acid fermentation to supply energy.

Essentially fermentation allows the anaerobic production of energy simply from glycolysis (outside of the mitochondria), without the need for krebs cycle and oxidative phosphorylation as used in respiration, but it is relatively inefficient and produces waste products, like lactic acid. In animals this lactate is then exported to the liver (the cori cycle) and converted to glucose by gluconeogenesis, which then feeds back into glycolysis. But with excessive reliance upon lactic acid fermentation for energy, for instance during intense periods of physical activity, there can be a temporary build up of lactic acid, since the body's ability to remove it is exceeded.

Bacterial lactic acid fermentation

Fermentation is often the primary pathway used for energy production in many anaerobic bacteria and yeasts in the gut. Different bacteria use different fermentation pathways to create a variety of waste products such as lactate, butyrate, acetate and ethanol (yeasts). These fermentation products are then absorbed through the intestine. 'Good' or 'bad' bacteria can partially be defined by how beneficial or toxic these substances are to us.

For lactic acid fermentation, first sugars such as glucose are converted to pyruvate via glycolysis, pyruvate is then reduced by the NADH formed from glycolysis, and lactate is formed. Every molecule of glucose (6 carbons) yields 2 of lactate (3 carbons).

There are a few forms of lactate; some bacteria produce l-lactate, some d-lactate and others a racemic dl-lactate. Humans create and can only efficiently metabolise l-lactate [4], so high levels of d-lactate can be harmful and induce d-lactic acidosis (neuro-cognitive symptoms[5]). D-lactate is produced by many streptococcus strains, but can also be produced by many lactobacillius (lactic acid bacteria) strains. The most common strains in supplements which produce d-lactate are lactobacillius acidophilus, plantarum and bulgarius[6]. A d-lactate free probiotic is available from custom probiotics. D-lactate can be tested for by Biolab (UK) and Metametrix (US).

Research
1. Increased d-lactic Acid intestinal bacteria in patients with chronic fatigue syndrome.
2. Ventricular cerebrospinal fluid lactate is increased in chronic fatigue syndrome
3. http://www.biolab.co.uk/docs/dlactate.pdf
4. D-Lactate in Human and Ruminant Metabolism

5. D-lactic acidosis. review.
6. Laboratory Evaluations. Richard S Lord.
7. http://en.wikipedia.org/wiki/Microbial_metabolism
8. http://commons.wikimedia.org/wiki/Category:Carbohydrate_metabolism
9. http://en.wikipedia.org/wiki/Metabolic_acidosis

Hypochlorhydria (low stomach acid)

2010-07-23T02:37:00.000-07:00

Anecdotal reports and practitioner experiences suggest stomach acid (Hydrochloric acid or HCl) levels are often low in CFS. This could be due to many reasons, such as infections (eg. h pylori), nutrient deficiencies or low ATP. Low stomach acid sets the stage for numerous digestive and dysbiotic issues, many CFS specialists consider correcting HCl levels as fundemental to any CFS treatment protocal.

HCl metabolism:
HCl is created by the parietal cells in the stomach which use an ATP-dependant enzyme (H/K ATPase) to create the large pH gradient between them and the blood, they then secrete HCl in response to food intake. Various neurotransmitters (acetylcholine and GRP) and hormones (gastrin and histamine) regulate HCl production, it is also regulated by negative feedback mechanisms. HCl is required in the first step of protein digestion (where protein is denatured), it sets up the right pH to trigger various digestive enzymes, and many minerals and vitamins (especially B12) require HCl for efficient absorption. HCl is also required to sterilise food and discourage growth of bad bacteria/yeast in the small intestine.

Thus low stomach acid levels can cause low amino acid and nutrient assimilation (digestion and absorption) and gut dysbiosis (bad bacteria overgrowth). Low stomach acid also perpetuates itself, since you can go deficient in various nutrients required to make HCl.

Home bicarb test:
There is a simple home test that can be done to give a good basic indicator of HCl levels. All you need is some bicarbonate of soda. This is the most common home test procedure on the net for testing stomach acid levels:

[Take 1 level teaspoon of bicarbonate of soda dissolved in a little water, on an empty stomach *. [*That means 2½ hours after breakfast, lunch or dinner where no other foods, supplements or drinks other than pure (still) water have been consumed since the last meal.] If sufficient acid is present in the stomach, the bicarbonate will be converted into CO2 gas, which produces significant bloating and belching within 5 –10 minutes. If this happens, further action is unlikely to be required unless CO2 production is excessive.]

Basic HCl support:
- A slice of lemon (pH2-3) squeezed into a small amount of water with/after each meal (drink through a straw).
- Cider vinegar with each meal (drink through a straw).
- B-vitamins, magnesium and potentially anything that helps energy metabolism in the parietal cells in the stomach.

Stronger HCl support:
- Betaine HCl supplements (may also stimulate betaine-dependant BHMT methylation pathway)
- Allergy research group 'Diluted pure HCl' (drink through a straw).

Further testing:
- http://www.nutri-linkltd.co.uk/documents/GastroTestInstructions.pdf
- Acumen VEGF

Methylation & Glutathione Pathway regulation.

2010-07-10T05:11:00.000-07:00

The methylation and transsulfuration pathways are under tonic modulation by various signalling molecules as well as homeostatic feedback modulation by various intermediates within the pathways themselves, most notably SAMe. Many of the effects of SAMe (adomet) on the activity of enzymes within these pathways can be seen as to ultimately act to homeostatically regulate its own production. For instance SAMe has been shown to induce CBS [1] and inhibit BHMT [2] and MTHFR [3,4]. SAMe has been shown in many studies to augment glutathione metabolism through induction of glutathione synthesis [5,6], protection of GCL activity [7,8], and dose-dependent induction of GST [9-12]. There is also the possibility that SAMe modulates GPX, GR and SODase activity [5,10,11]. Below are some of the other modulators of various key enzymes within the methylation and transsulfuration pathways.

CBS (3 regulatory domains activated by p5p, SAMe and redox [13])

CBS activity is induced by SAMe (via enzyme stabilisation) [14], testosterone [15], vitamin D [16], and by neuronal Ca2+/calmodulin [17,18]. CBS is modulated via redox (fe(III) & CO) [13,19] and notably inhibited by peroxynitrite [20].

DHFR

Inhibited by peroxynitrite [21]

MAT

GSH/GSSG redox balance [22]

Glutathionylcobalamin

I don’t think cellular cobalamin (B₁₂) metabolism is completely pinned down yet, but below is a nice diagram for how cobalamin metabolism likely works once the transcobalamin carrier protein has delivered it from blood to cell.

OH-cobalamin (hydroxy or aquacobalamin) forms an irreversible 1:1 complex with glutathione called glutathionylcobalamin, which is thought to serve as a precursor to the active coenzyme forms: methylcobalamin and adenosylcobalamin [23,24]. In this way glutathione can protect cobalamin from oxidation [25]. Recent research supports the importance of glutathione in cobalamin metabolism; in rats chronic ethanol consumption depletes MS (methionine synthase) activity in a glutathione-dependant manner [26].

References

[1] M. Janosík, V. Kery, M. Gaustadnes, K.N. Maclean, J.P. Kraus, Regulation of human cystathionine beta-synthase by S-adenosyl-L-methionine: evidence for two catalytically active conformations involving an autoinhibitory domain in the C-terminal region., Biochemistry. 40 (2001) 10625-33.

[2] X. Ou, H. Yang, K. Ramani, A.I. Ara, H. Chen, J.M. Mato, et al., Inhibition of human betaine-homocysteine methyltransferase expression by S-adenosylmethionine and methylthioadenosine., The Biochemical Journal. 401 (2007) 87-96.

[3] D.A. Jencks, R.G. Mathews, Allosteric inhibition of methylenetetrahydrofolate reductase by adenosylmethionine. Effects of adenosylmethionine and NADPH on the equilibrium between active and inactive forms of the enzyme and on the kinetics of approach to equilibrium., The Journal of Biological Chemistry. 262 (1987) 2485-93.

[4] R.G. Matthews, S.C. Daubner, Modulation of methylenetetrahydrofolate reductase activity by S-adenosylmethionine and by dihydrofolate and its polyglutamate analogues., Advances in Enzyme Regulation. 20 (1982) 123-31.

[5] J.P. De La Cruz, J. Pavía, J.A. González-Correa, P. Ortiz, F. Sánchez de la Cuesta, Effects of chronic administration of S-adenosyl-L-methionine on brain oxidative stress in rats., Naunyn-Schmiedeberg’s Archives of Pharmacology. 361 (2000) 47-52.

[6] M.L. Mesa, R. Carrizosa, C. Martínez-Honduvilla, M. Benito, I. Fabregat, Changes in rat liver gene expression induced by thioacetamide: protective role of S-adenosyl-L-methionine by a glutathione-dependent mechanism., Hepatology (Baltimore, Md.). 23 (1996) 600-6.

[7] H. Yang, K. Ramani, M. Xia, K.S. Ko, T.W.H. Li, P. Oh, et al., Dysregulation of glutathione synthesis during cholestasis in mice: molecular mechanisms and therapeutic implications., Hepatology (Baltimore, Md.). 49 (2009) 1982-91.

[8] K. Ko, H. Yang, M. Noureddin, A. Iglesia-Ara, M. Xia, C. Wagner, et al., Changes in S-adenosylmethionine and GSH homeostasis during endotoxemia in mice., Laboratory Investigation; a Journal of Technical Methods and Pathology. 88 (2008) 1121-9.

[9] F. Tchantchou, M. Graves, D. Falcone, T.B. Shea, S-adenosylmethionine mediates glutathione efficacy by increasing glutathione S-transferase activity: implications for S-adenosyl methionine as a neuroprotective dietary supplement., Journal of Alzheimer’s Disease : JAD. 14 (2008) 323-8.

[10] R.A. Cavallaro, A. Fuso, V. Nicolia, S. Scarpa, S-adenosylmethionine prevents oxidative stress and modulates glutathione metabolism in TgCRND8 mice fed a B-vitamin deficient diet., Journal of Alzheimer’s Disease : JAD. 20 (2010) 997-1002.

[11] J.A. Gonzalez-Correa, J.P. De La Cruz, E. Martin-Aurioles, M.A. Lopez-Egea, P. Ortiz, F. Sanchez de la Cuesta, Effects of S-adenosyl-L-methionine on hepatic and renal oxidative stress in an experimental model of acute biliary obstruction in rats., Hepatology (Baltimore, Md.). 26 (1997) 121-7.

[12] F. Tchantchou, M. Graves, D. Ortiz, A. Chan, E. Rogers, T.B. Shea, S-adenosyl methionine: A connection between nutritional and genetic risk factors for neurodegeneration in Alzheimer’s disease., The Journal of Nutrition, Health & Aging. 10 (2006) 541-4.

[13] K.-H. Jhee, W.D. Kruger, The role of cystathionine beta-synthase in homocysteine metabolism., Antioxidants & Redox Signaling. 7 (2005) 813-22.

[14] A. Prudova, Z. Bauman, A. Braun, V. Vitvitsky, S.C. Lu, R. Banerjee, S-adenosylmethionine stabilizes cystathionine beta-synthase and modulates redox capacity., Proceedings of the National Academy of Sciences of the United States of America. 103 (2006) 6489-94.

[15] V. Vitvitsky, A. Prudova, S. Stabler, S. Dayal, S.R. Lentz, R. Banerjee, Testosterone regulation of renal cystathionine beta-synthase: implications for sex-dependent differences in plasma homocysteine levels., American Journal of Physiology. Renal Physiology. 293 (2007) F594-600.

[16] C. Kriebitzsch, L. Verlinden, G. Eelen, N.M. van Schoor, K. Swart, P. Lips, et al., 1,25-dihydroxyvitamin D(3) influences cellular homocysteine levels in murine pre-osteoblastic MC3T3-E1 cells by direct regulation of cystathionine β-synthase., Journal of Bone and Mineral Research : The Official Journal of the American Society for Bone and Mineral Research. (2011).

[17] K. Qu, S.W. Lee, J.S. Bian, C.-M. Low, P.T.-H. Wong, Hydrogen sulfide: neurochemistry and neurobiology., Neurochemistry International. 52 (2008) 155-65.

[18] K. Eto, H. Kimura, A novel enhancing mechanism for hydrogen sulfide-producing activity of cystathionine beta-synthase., The Journal of Biological Chemistry. 277 (2002) 42680-5.

[19] R. Banerjee, C.-G. Zou, Redox regulation and reaction mechanism of human cystathionine-beta-synthase: a PLP-dependent hemesensor protein., Archives of Biochemistry and Biophysics. 433 (2005) 144-56.

[20] L. Celano, M. Gil, S. Carballal, R. Durán, A. Denicola, R. Banerjee, et al., Inactivation of cystathionine beta-synthase with peroxynitrite., Archives of Biochemistry and Biophysics. 491 (2009) 96-105.

[21] S. Pucciarelli, M. Spina, F. Montecchia, G. Lupidi, A.M. Eleuteri, E. Fioretti, et al., Peroxynitrite-mediated oxidation of the C85S/C152E mutant of dihydrofolate reductase from Escherichia coli: functional and structural effects., Archives of Biochemistry and Biophysics. 434 (2005) 221-31.

[22] M.L. Martínez-Chantar, M.A. Pajares, Role of thioltransferases on the modulation of rat liver S-adenosylmethionine synthetase activity by glutathione., FEBS Letters. 397 (1996) 293-7.

[23] L. Xia, A.G. Cregan, L.A. Berben, N.E. Brasch, Studies on the formation of glutathionylcobalamin: any free intracellular aquacobalamin is likely to be rapidly and irreversibly converted to glutathionylcobalamin., Inorganic Chemistry. 43 (2004) 6848-57.

[24] E. Pezacka, R. Green, D.W. Jacobsen, Glutathionylcobalamin as an intermediate in the formation of cobalamin coenzymes., Biochemical and Biophysical Research Communications. 169 (1990) 443-50.

[25] W.P. Watson, T. Munter, B.T. Golding, A new role for glutathione: protection of vitamin B12 from depletion by xenobiotics., Chemical Research in Toxicology. 17 (2004) 1562-7.

[26] M.I. Waly, K.K. Kharbanda, R.C. Deth, Ethanol lowers glutathione in rat liver and brain and inhibits methionine synthase in a cobalamin-dependent manner., Alcoholism, Clinical and Experimental Research. 35 (2011) 277-83.

Klebsiella Pneumoniae

2010-06-29T10:45:00.000-07:00

Klebsiella Pneumoniae is a common bacterium found to be overgrown in states of dysbiosis. I will compile some information about it here as i find it.

Klebsiella Pneumoniae is part of the enterobacteriaceae family and is a gram negative, encapsulated, facultative anaerobic bacterium; it is also oxidase-negative, so can't use oxygen for energy.

Klebsiella Pneumoniae is reported as being able to grow well on FOS [6] (fructooligosaccharides), which is composed of short chain fructose molecules (<5); it can't however metabolise inulin [6], which is composed of long chain (>10) fructose molecules.

Klebsiella Pneumoniae is inhibited by triphala [3], buytrate (at low ph) [1,2], cumin [7], garlic [8,9,10,11], oregano oil [12,13], bay oil [13] and olive leaf extract [4,5].

Research
1. The effect of pH on the inhibition of bacterial growth by physiological concentrations of butyric acid: implications for neonates fed on suckled milk.
2. Effect of colon flora and short-chain fatty acids on growth in vitro of Pseudomonas aeruginsoa and Enterobacteriaceae.
3. Evaluation of the growth inhibitory activities of Triphala against common bacterial isolates from HIV infected patients.
4. Phenolic compounds and antimicrobial activity of olive (Olea europaea L. Cv. Cobrançosa) leaves.
5. Adsorption of olive leaf (Olea europaea L.) antioxidants on silk fibroin.
6. The Role of Bifidobacteria in Health.
7. Effect of cumin (Cuminum cyminum) seed essential oil on biofilm formation and plasmid Integrity of Klebsiella pneumoniae.
8. In vitro activity of garlic oil and four diallyl sulphides against antibiotic-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae
9. Investigation on the antibacterial properties of garlic (Allium sativum) on pneumonia causing bacteria.
10. Antimicrobial activity of extracts of local cough mixtures on upper respiratory tract bacterial pathogens
11. An in vitro assessment of the antibacterial effect of garlic (Allium sativum) on bacterial isolates from wound infections.
12. Minimum inhibitory concentrations of herbal essential oils and monolaurin for gram-positive and gram-negative bacteria.
13. Antimicrobial activity of essential oils and other plant extracts.

GPX (glutathione peroxidase) mimics.

2010-06-27T05:07:00.000-07:00

I have quite low GPX1 activity (as measured by biolab) that doesnt completely fix with selenium supplementation, inspite of normal GSH levels and GPX3 activity. Subsequent testing has found this is due to a DNA adduct inhibiting full activity of the enzyme. I think there may be some others out there in a similar position. If this is the case then i think the best thing to do is keep it functioning at its best with selenium supplementation and take some load of its peroxide scavenging role by boosting other antioxidants. Another possibility lies in the GPX mimics below, these compounds can act as a surrogate for GPX:

1. Ebselen is a seleno-organic compound thats acts like a GPX (glutathione peroxidase) mimic, that is it can perform the roles of endogenus GPX, like scavenging hydrogen peroxide. It also scavenges peroxynitrite, induces phase II detox enzymes such as GST, and is neuroprotective against excessive NMDAR activity.

2. BXT-51072 is a GPX mimic compund made by oxis research.

Research
- http://en.wikipedia.org/wiki/Ebselen
- Ebselen, a Glutathione Peroxidase Mimetic Seleno-organic Compound, as a Multifunctional Antioxidant
- Neuroprotection of ebselen against ischemia/reperfusion injury involves GABA shunt enzymes.
- http://www.oxisresearch.com/gpx.html

Magnesium and GSH research.

2010-06-26T08:01:00.000-07:00

- Several clinical studies show that cellular magnesium levels dont replete in glutathione deficient patients:
PMID: 10872900, PMID: 10406827, PMID: 8054261.

- Magnesium loss induces oxidative stress which can cause glutathione loss. Mg supplementation can improve GSH levels:
PMID: 8760069, PMID: 18705541, PMID: 18516713.

Coconut oil

2010-06-12T10:15:00.000-07:00

Antimicrobial properties
Coconut oil is comprised mainly of medium-chain fatty acids (6-12 carbons), such as lauric acid (50%), capric acid, and caprylic acid (aka octanoic acid). These fatty acids (alone and together) can disrupt the cell membranes of some potentially pathogenic gram-positive bacteria and fungi (such as staphylococci, streptococci A and B, clostridia, and candida albicans), giving coconut oil significant antimicrobial activity.

The monoglyceride forms of the active fatty acids in coconut oil can be even more potent. For instance Monolaurin, which is found in high concentrations in breast milk, has broad antimicrobial activity against lipid-coated bacteria and viruses (http://www.lauricidin.com/micro.asp). Only small amounts of the fats in coconut oil will be converted to their respective monoglyceride forms in the body though, so Monolaurin must be taken as a supplement to get its benefits.

Coconut oil metabolism
Unlike other dietary fats, the medium-chain fats in coconut oil can be absorbed directly in the intestine and delivered straight into the blood stream, with no need for the usual fat digestion via lipase and bile. Research shows coconut oil is not stored like other fats, it is instead metabolised quickly by the liver, it also has no negative effect on cholesterol and doesnt increase requirements for fat-soluble antioxidants.

Conversion to energy
Coconut oil has some advantages over other fats when it comes to energy production. With most fats they are transported into the mitochondria by carnitine, then oxidised in a process called beta-oxidation which provides acetyl-CoA for krebs cycle and ultimately produces ATP. Most tissues can oxidise fats for energy, that is except for the brain. The medium-chain fats found in coconut are a little different, they have the additional benefit of the liver also converting them into ketone bodies which can then be used by the brain (and heart) for energy alongside glucose. Futhermore, the caprylic acid (aka octanoic acid) in coconut oil is the precursor to lipoic acid synthesis in the mitochondria. lipoic acid is an essential cofactor in aerobic energy metabolism.

Coconut oil information
- http://en.wikipedia.org/wiki/Coconut_oil
- http://www.coconutoil.com/index.html
- http://products.mercola.com/coconut-oil/
- Coconut Oil – Ideal Fat next only to Mother’s Milk (Scanning Coconut’s Horoscope).
- http://www.coconutketones.com/

Antimicrobial research
- In vitro antimicrobial properties of coconut oil on Candida species in Ibadan, Nigeria.
- Sporostatic effect of some oils against fungi causing otomycosis.
- In vitro killing of Candida albicans by fatty acids and monoglycerides.
- Palmitoleic acid isomer (C16:1delta6) in human skin sebum is effective against gram-positive bacteria.
- Whey-derived free fatty acids suppress the germination of Candida albicans in vitro.
- Purification and identification of bovine cheese whey fatty acids exhibiting in vitro antifungal activity.
- Antibacterial effect of caprylic acid and monocaprylin on major bacterial mastitis pathogens.
- Antimicrobial activities of components of the glandular secretions of leaf cutting ants of the genus Atta.
- The antimicrobial properties of milkfat after partial hydrolysis by calf pregastric lipase.
- Susceptibility of Clostridium perfringens to C-C fatty acids
- Antimicrobial activity of monocaprin: a monoglyceride with potential use as a denture disinfectant.
- Antibacterial study of the medium chain fatty acids and their 1-monoglycerides: individual effects and synergistic relationships.
- Killing of Gram-positive cocci by fatty acids and monoglycerides.
- A novel antibacterial agent derived from the C-terminal domain of streptococcus mutans GTP-binding protein.
- The inhibitory action of fatty acids on oral bacteria.
- Effect of sucrose monolaurate on acid production, levels of glycolytic intermediates, and enzyme activities of Streptococcus mutans NCTC 10449.
- http://www.lauricidin.com/micro.asp
- http://en.wikipedia.org/wiki/Viral_envelope
Topical antimicrobial activity
- The antimicrobial activity of liposomal lauric acids against Propionibacterium acnes.
- Novel antibacterial and emollient effects of coconut and virgin olive oils in adult atopic dermatitis.
- Inhibition of growth of dermatophytes by Indian hair oils.
- Novel antibacterial activity of monolaurin compared with conventional antibiotics against organisms from skin infections: an in vitro study.
Metabolism
- Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity.
- Dietary lipids modify redox homeostasis and steroidogenic status in rat testis.
- http://www.coconutketones.com/

Neopterin as a marker of TH1 immune activation.

2010-06-12T05:21:00.000-07:00

Neopterin can be used a reliable marker for assessing the degree of TH1 mediated immune activation.

The mechanism of neopterin release in short:
- An activated TH1 cell stimulates the cytokine, 'interferon-gamma';
- This stimulates BH4 synthesis (leading to NO synthesis);
- Which triggers the release of neopterin from macrophages.

Interferon-gamma is the only cytokine that directly stimulates neopterin release but other cytokines can indirectly amplify neopterin formation through TH1 stimulation. Neopterin is a stable molecule, its half life in the body govened by renal excretion, so it is a reliable marker for the degree of TH1 immune activation.

More information:
- http://www.metametrix.com/files/learning-center/articles/Neopterin-Biopterin.pdf
- http://en.wikipedia.org/wiki/Neopterin
- http://www.neopterin.net/neopterin_e.pdf

Nitric oxide (NO) and oxidative stress.

2010-05-25T06:25:00.000-07:00

Nitric oxide (NO) is a gas with a very short half life that is produced endogenously in the body. It has roles in many essential functions including vasodilation, neurotransmission, inflammation, erection, and immunity. It is also implicated in many chonic illnesses especially those involving chronic inflammation.

Nitric oxide is produced by the NOS (nitric oxide synthase) family of enzymes, which convert 1 molecule of arginine to 1 molecule of citrulline and NO. They require several cofactors, the most important of which is BH4 (tetrahydrobiopterin). 2 molecules of BH4 are needed for normal NOS enzyme function. However when there is insufficient BH4, NOS can also produce superoxide, which combines with NO to form peroxynitrite, turning the NOS enzymes into a potent source of oxidising free radicals. This change in NOS output is known as 'uncoupling', because its become uncoupled from its normal function of NO production.

The free radical peroxynitrite (ONOO−) has the ability to oxidise BH4 to BH3 which causes further NOS uncoupling. Vitamin C can prevent peroxynitrite induced uncoupling by recycling BH3 back to BH4. NO and peroxynitrite can inhibit mitochondrial function. Peroxynitrite and its breakdown products also inhibit the key homocysteine degrading CBS enzyme and trigger inflammation pathways (iNOS) leading to more NO and peroxynitrite formation. High levels of NO and/or peroxynitrite can also contribute to excitotoxicity, since both can inhibit enzymes involved in energy metabolism, causing ATP depletion.

NO-OONO
M.Pall has put together a theory (NO-OONO theory) to explain CFS and other multisystemic illnesses which is based upon NOS decoupling, the resultant oxidative stress, and a theoretical visous cycle involving chronic inflammation. This theory is eludicated in his book, 'explaining unexplained illnesses'.

References
- Role of oxidative stress and nitric oxide in atherothrombosis.
- Mitochondrial function and dysfunction in sepsis.
- Nitric oxide and oxidative stress in vascular disease.
- Peroxynitrite is the major species formed from different flux ratios of co-generated nitric oxide and superoxide: direct reaction with boronate-based fluorescent probe.
- Peroxynitrite induces destruction of the tetrahydrobiopterin and heme in endothelial nitric oxide synthase: transition from reversible to irreversible enzyme inhibition.
- Persistent mitochondrial damage by nitric oxide and its derivatives: neuropathological implications.
- Tetrahydrobiopterin protects the kidney from ischemia-reperfusion injury.
- The multiple actions of NO.
- Inactivation of cystathionine beta-synthase with peroxynitrite.
- Endothelial nitric oxide synthase uncoupling and perivascular adipose oxidative stress and inflammation contribute to vascular dysfunction in a rodent model of metabolic syndrome.
- Multiple pathways of peroxynitrite cytotoxicity.
- Ascorbate enhances iNOS activity by increasing tetrahydrobiopterin in RAW
264.7 cells.
- Interactions of peroxynitrite, tetrahydrobiopterin, ascorbic acid, and thiols:
implications for uncoupling endothelial nitric-oxide synthase.
- Interactions of peroxynitrite with uric acid in the presence of ascorbate and
thiols: implications for uncoupling endothelial nitric oxide synthase.
- L-ascorbic acid potentiates endothelial nitric oxide synthesis via a chemical
stabilization of tetrahydrobiopterin.
- 'Explaining unexplained illnesses' (paperback) M.Pall

General NO info
- http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NO.html
- http://en.wikipedia.org/wiki/Biological_functions_of_nitric_oxide

BH4 salvage pathway.

2010-05-25T06:14:00.000-07:00

BH4 (tetrahydrobiopterin) is a required cofactor for the first and rate-limiting steps in serotonin and dopamine synthesis as well as for NO (nitric oxide) production. BH4 deficiency may occour in some chronic illnesses, and loss of BH4 is implicated in oxidative stress mechanisms since it causes 'decoupling' of the NOS enzymes (check my nitric oxide post). BH4 is tricky to supplement though, mostly due to its instability.

In the body 5-methyl-THF (active folate) can regenerate BH4 from oxidised BH2, so good folate levels are important for maintaining BH4 levels. But i learnt recently you can also boost BH4 levels with plain old synthetic folic acid via a different mechanism.

As well as the main de novo (from new) synthesis pathway for BH4, there is a salvage pathway that uses the DHFR enzyme to convert BH2 to BH4 (1,2,6). The DHFR enzyme is at the start of folate metabolism, and normally converts inactive folate forms to active THF forms. Folic acid supplements enter folate metabolism before DHFR and have been shown to boost intracellur BH4 by stimulation of DHFR (2,3,4,5,6). I think the active forms of supplemental folate (folinic acid and methyl-THF) wont stimulate this enzyme much, so i guess combined 5-methyl-THF and folic acid supplementation may be best to support BH4 levels.

There is one hitch though, unfortunately there is 5-fold variability in DHFR activity in humans(8), so some people may not be able to make as good use of the BH4 salvage pathway as others.

Basic folate metabolism
folate → DHF (dihydrofolate) → THF (tetrahydrofolate) ↔ methylene-THF → methyl-THF

BH4 metabolism

References
1. http://www.food-chemistry.com/Research/neu%20biosynthesis%20of%20folates%20and%20BH4.htm
2. laboratory evaluations, richard s lord. (p.35)
3. http://cat.inist.fr/?aModele=afficheN&cpsidt=17594313
4. http://www.ncbi.nlm.nih.gov/pubmed/2862841
5. http://cat.inist.fr/?aModele=afficheN&cpsidt=17676232
6. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=393638
7. http://www.bh4.org/pdf/channon.pdf
8. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=2730961&blobtype=pdf

B12 Absorption (research review)

2010-05-25T06:11:00.000-07:00

Introduction
Unlike most nutrients, absorption of vitamin B12 (cobalamin) begins in the mouth, where small amounts of unbound crystalline B12 can be absorbed through the mucosa membrane (3). Most dietary B12 is protein-bound and dependant on HCI and proteolytic enzymes to release it, after which it must be attached to intrinsic factor (IF) protein for absorption in the small intestine. Once absorbed it is then transferred to the transcobalamin proteins, which carry B12 in the blood. B12 is also excreted and reabsorbed from the bile, via enterohepatic circulation.

At dietary level doses B12 absorption is high in healthy individuals, around 50% at 1ug dose, 20% at a 5ug dose, and 5% at a 25ug dose (3). Total B12 absorption is limited mainly because IF protein is saturated by relatively small doses, but the second of two doses given 4-6 hours apart is absorbed as well as the first (3). With old age absorption of protein-bound B12 is decreased, whereas absorption of free crystalline B12 does not decline with advancing age (9).

Supplemental B12
There are currently four forms of supplemental B12 available:
- cyanocobalamin (synthetic B12 form);
- hydroxycobalamin (aka aquacobalamin);
- methylcobalamin;
- adenosylcobalamin (aka dibencozide);
- a possible fifth form is glutathionylcobalamin (17).

Supplemental B12 is free and not protein-bound, so at large doses (500ug+) this allows for a significant degree of absorption in the mouth and along the intestine via passive diffusion. By this way large oral doses are an effective alternative to IV cobalamin in treating the neurological and haematological symptoms seen in B12 deficiency, even in those with low intrinsic factor or who have already developed pernicious anaemia (4,5,6,7). Supplemental B12 can also be absorbed entirely via sublingual delivery very effectively (1,8). But according to one study (1), there is no significant difference in absorption between 500ug cyanocobalamin taken orally or sublingually, both ways increase serum b12 levels and decrease MMA and tHcy similarly (1). Another study shows that nasal hydroxycobalamin spray also gives a substantial increase in serum b12 levels (11). Research suggests that there is not much difference in IF protein bound absorption between the cyano/hydroxy/methyl and adenosylcobalamin forms (14,15). Although the coenzyme methyl and adenosyl-b12 forms are susceptible to photolysis (13,14,15), making them less stable in the GI tract. Finally, less cyanocobalamin is retained in the body compared to other B12 forms (15,16).

My questions:
- Which B12 forms are best absorbed via passive diffusion?
- Does the supplement brand and composition affect stability and absorption significantly (cyclodextrins, liposomes, etc)?
- How much higher might transdermal absorption be?

References
1. Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route
2. http://en.wikipedia.org/wiki/Vitamin_B12#Human_absorption_and_distribution
3. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/306-356_150.pdf
4. Treatment of vitamin b(12)-deficiency anemia: oral versus parenteral therapy.
5. Oral versus intramuscular cobalamin treatment in megaloblastic anemia: a single-center, prospective, randomized, open-label study.
6. Oral cobalamin (vitamin B(12)) treatment. An update.
7. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials.
8. Sublingual therapy for cobalamin deficiency as an alternative to oral and parenteral cobalamin supplementation.
9. Vitamin B12 deficiency in the elderly.
10. http://www.aor.ca/html/products.php?id=34
11. Hydroxocobalamin, a nitric oxide scavenger, in the prophylaxis of migraine: an open, pilot study.
12. http://www.veganhealth.org/b12/dig
13. Nitric oxide interactions with cobalamins: biochemical and functional consequences.
14. Intestinal absorption and concurrent chemical changes of methylcobalamin.
15. http://www.thorne.com/media/coenzymeb12.pdf
16. Cyanocobalamin--a case for withdrawal: discussion paper.
17. PMID: 15606130, PMID: 19409980, PMID: 15476387, PMID: 2357215
18. Laboratory evalulations - richard s lord.

Melatonin Research.

2010-05-25T06:08:00.000-07:00

Wiki covers melatonin's main roles in the body quite comprehensively, so below is a summary.

Melatonin is a hormone released from the pineal gland at night to induce sleep. It is synthesised from serotonin which first undergoes acetylation then methylation to form melatonin. Much of melatonin's activity is carried out by melatonin receptors (MT1 and MT2), which upon activation lower cAMP [18]. Melatonin is metabolised in the liver, where 90% is cleared in a single passage. Melatonin release is inhibited by light and some drugs. Melatonin is also a powerful antioxidant that directly scavenges free radicals, but does not undergo redox cycling (cant be regenerated or 'reduced') like some other antioxidants (vitamin C, E, etc), instead it is a terminal antioxidant that forms stable oxidised end products.

Neurological melatonin research
Below is some melatonin research with special relevance to chronic neurological illnesses:
- Melatonin is a gaba agonist (1-6,17), and neuroprotective against excessive glutamate (5,13,14). Gaba modulates the circadian rhythm and melatonin synthesis (7,8), low gaba knocks out the circadian rhythm and inhibits melatonin synthesis (8).
- Melatonin increases synthesis of endogenus antioxidant enzymes (14,15,16), and can protect all subcellular compartments (incl mitochondria) from oxidative stress (9,10,11,16).
- Beta blockers decrease melatonin release (12).

References
1. Effects of chronic melatonin administration on GABA and diazepam binding in rat brain.
2. Electrophysiological Effects of Melatonin on mouse Per1 and non-Per1 Suprachiasmatic Nuclei (SCN) neurones in vitro.
3. Melatonin potentiates the GABA(A) receptor-mediated current in cultured chick sp.
4. Drugs for sleep disorders: mechanisms and therapeutic prospects.
5. Neuroprotection against Abeta and glutamate toxicity by melatonin: are GABA receptors involved?
6. Stimulation of melatonin receptors decreases calcium levels in Xenopus tectal cells by activating GABAC receptors.
7. An autonomous circadian clock in the inner mouse retina regulated by dopamine and GABA.
8. The Role of GABA in the Regulation of the Melatonin Circadian Rhythm in the Rat Retina.
9. Melatonin, cardiolipin and mitochondrial bioenergetics in health and disease.
10. Melatonin role in the mitochondrial function.
11. Melatonin inhibits cardiolipin peroxidation in mitochondria and prevents the mitochondrial permeability transition and cytochrome c release.
12. Influence of beta-blockers on melatonin release.
13. Reduced oxidative damage in ALS by high-dose enteral melatonin treatment.
14. Neuroprotective role of melatonin in oxidative stress vulnerable brain.
15. Melatonin oxidative stress and neurodegenerative diseases.
16. Actions of melatonin in the reduction of oxidative stress. A review.
17. Melatonin and anesthesia: a clinical perspective.
18. MELATONIN RECEPTORS

Lithium - neuroprotection & neurotrophism

2010-05-25T05:04:00.000-07:00

Lithium is a mineral found naturally in our diet, which some people think it should be deamed 'essential' due to many studies showing the negative effects of deficiency. Lithium levels are noted to be low in those with various mood disorders and aggressive behaviors, and higher in those of high academic standing. Lithium is perhaps most well known for its pharmaceutical use in the treatment of bipolar depression, where it is taken at high doses in salt form (as citrate and carbonate). At these doses there is a narrow therapeutic window beyond which it is toxic. Lithium has also been studied for its neuroprotective and neurotrophic effects; supplemental lithium has been shown to protect against excitotoxicty and robustly increase grey matter in many brain regions. Major mechanisms behind lithium's effects include inhibition of GSK-3b (via competition with Mg2+), activation of the ERK-MAP signalling cascade, increased bcl-2 expression, and modulation of NMDA and AMPA receptor activity. In manic animal models, lithium decreases AMPAR activity, whereas the antidepressant activity of lithium is dependent upon increased AMPAR activity.

There is a notion that lithium can also be as effective for mood disorders at lower doses when taken as lithium orotate (an organic form), which is thought to be better absorbed and have far superioir intracellular transport via the orotic carrier molecule. However i should point out that almost all research on lithium has been done with the salt forms, and there is relatively sparse and conflicting research regarding lithium orotate's metabolism. Either way, correcting a lithium deficiency with lithium orotate should be helpful. Lithium orotate is available from many supplement brands, although some arent apparently selling 'true' fully reacted lithium orotate, and instead sell a lithium salt/orotic acid mixure which wouldnt be as effective. I've contacted VRP (vitamin research products) and they assure me they make their own fully reacted lithium orotate, i think this may also be the one sold and rebranded in yasko's 'holistic heal' store, and it is also available from many other sites in the UK and US.

Neuroprotective research
- Lithium protection against glutamate excitotoxicity in rat cerebral cortical neurons
- Lithium protection from glutamate excitotoxicity: therapeutic implications
- Lithium prevents excitotoxic cell death of motoneurons in organotypic slice cultures of spinal cord.
- Lithium therapy improves neurological function and hippocampal dendritic arborization in a spinocerebellar ataxia type 1 mouse model.
- Lithium: occurrence, dietary intakes, nutritional essentiality.
- The use of mood stabilizers as plasticity enhancers in the treatment of neuropsychiatric disorders.
- GSK-3alpha regulates production of Alzheimer's disease amyloid-beta peptides
- Lithium-induced increase in human brain grey matter.
- Lithium at 50: have the neuroprotective effects of this unique cation been overlooked?
- Rat brain and serum lithium concentrations after acute injections of lithium carbonate and orotate.
- The clinical applications of lithium orotate. A two years study.
- Lithium treatment alters brain concentrations of nerve growth factor, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor in a rat model of depression.
- The role of lithium in the treatment of bipolar disorder: convergent evidence for neurotrophic effects as a unifying hypothesis.
- Lithium and neuropsychiatric therapeutics: neuroplasticity via glycogen synthase kinase-3beta, beta-catenin, and neurotrophin cascades.
- Lithium up-regulates the cytoprotective protein Bcl-2 in the CNS in vivo: a role for neurotrophic and neuroprotective effects in manic depressive illness.
- Molecular effects of lithium.
- Enhancement of Hippocampal Neurogenesis by Lithiu
- Lithium regulates hippocampal neurogenesis by ERK pathway and facilitates recovery of spatial learning and memory in rats after transient global cerebral ischemia.
- Lithium Restores Neurogenesis in the Subventricular Zone of the Ts65Dn Mouse, a Model for Down Syndrome.
- Glucocorticoids and lithium in adult hippocampal neurogenesis.
- Neuroprotective actions of lithium
Lithium orotate research
- Rat brain and serum lithium concentrations after acute injections of lithium carbonate and orotate.
- Lithium orotate, carbonate and chloride: pharmacokinetics, polyuria in rats.
- AOR lithium orotate

Neurogenesis & Gliogenesis

2010-05-25T04:58:00.000-07:00

Neurogenesis and gliogenesis refer to the production of new neurons and glia (aka. glial cells) respectively. It used to be thought that adults did not continue to grow new brain cells, but research from the last decade has shown otherwise. The most active area for adult neurogenesis appears to be in the hippocampus where it is important for learning and memory function, but research is also showing neurogenesis occurs in many other areas of the brain, including recently the cortex. Neurogenic and gliogenic regions of the brain contain multipotent neural stem cells from which new neurons and glia are formed. This process is stimulated and regulated by growth factors called neurotrophins, such as BDNF (brain-derived neurotrophic factor).

Neurogenesis decreases with age, and is markedly decreased in chronic neurological illnesses, along with decreased brain grey matter (which is composed of neurons and glia). Depression is associated with decreased neurogenesis, and it is thought that some of the positive effects of antidepressants may be due to stimulating BDNF and neurogenesis. CFS has also been associated with decreased brain grey matter which correlates illness severity.

Many factors influence overall neurogenesis. It has been shown that psychological stress, hypercortisol, alcoholism, hypothyroidism, and nutrient deficiencies (folate, vit D, omega3, etc) slow down the birth of new neurons; whereas aerobic activity, enriched environments (cognitive stimulation and learning), and certain nutrients and drugs can stimulate neurogenesis. Natural neurogenesis promoters include lithium, omega3 (and 3:6 balance), pantethine (active B5), blueberries, curcumin, vitamin D, T3 (thyroid hormone), and ginkgo bilboa components (bilobalide and quercetin). Psychological therapies such as meditation, CBT and NLP can also stimulate neurogenesis.

Natural neurogenesis promoters:
- Lithium has neurogenic and neuroprotective effects. (see my lithium post)
- Omega 3s, and 3:6 balance affects neurogenesis and boosts grey matter.
- Pantethine (active b5) helps provide cysteamine for BDNF synthesis, which slimulates neuron growth and survival.
- Aerobic excercise boosts neurogenesis by increasing uptake of blood-borne IGF-I to the brain.
- Blueberries boost neurogenesis.
- Curcumin boosts endogenus antioxidants, detoxification and neurogenesis.
- Vitamin D modulates neurotrophin production.
- T3 (Triiodothyronine - thyroid hormone), selenium required for T4 to T3 conversion.
- Ginkgo bilboa components, bilobalide and quercetin, boost neurogenesis.

Research
- Gray matter volume reduction in the chronic fatigue syndrome.
- Omega-3 fatty acids upregulate adult neurogenesis
- Impact of diet on adult hippocampal neurogenesis
- Docosahexaenoic acid promotes neurogenesis in vitro and in vivo.
- High-resolution magnetic resonance imaging in the study of fatty acid interventions in schizophrenia, depression, chronic fatigue syndrome and Huntington’s disease. BASANT K. PURI
- Physical activity and antidepressant treatment potentiate the expression of specific brain-derived neurotrophic factor transcripts in the rat hippocampus.
- Circulating Insulin-Like Growth Factor I Mediates Exercise-Induced Increases in the Number of New Neurons in the Adult Hippocampus.
- Exercise enhances learning and hippocampal neurogenesis in aged mice.
- The relationship between aerobic exercise and cognition: is movement medicinal?
- Exercise: a behavioral intervention to enhance brain health and plasticity
- Voluntary exercise following traumatic brain injury: brain-derived neurotrophic factor upregulation and recovery of function.
- Insulin-like growth factor I interfaces with brain-derived neurotrophic factor-mediated synaptic plasticity to modulate aspects of exercise-induced cognitive function.
- Adult hippocampal neurogenesis and c-Fos induction during escalation of voluntary wheel running in C57BL/6J mice.
- Fruit Polyphenols and Their Effects on Neuronal Signaling and Behavior in Senescence
- Early Anti-Oxidative and Anti-Proliferative Curcumin Effects on Neuroglioma Cells Suggest Therapeutic Targets.
- Curcumin reverses impaired hippocampal neurogenesis and increases serotonin receptor 1A mRNA and brain-derived neurotrophic factor expression in chronically stressed rats
- Dietary curcumin counteracts the outcome of traumatic brain injury on oxidative stress, synaptic plasticity, and cognition
- Neuroprotective and anti-ageing effects of curcumin in aged rat brain regions
- Curcumin Stimulates Proliferation of Embryonic Neural Progenitor Cells and Neurogenesis in the Adult Hippocampus.
- Spirulina promotes stem cell genesis and protects against LPS induced declines in neural stem cell proliferation.
- Neurogenesis in the adult mammalian brain.
- The thyroid hormone, triiodothyronine, enhances fluoxetine-induced neurogenesis in rats: possible role in antidepressant-augmenting properties.
- Thyroid hormone regulates hippocampal neurogenesis in the adult rat brain.
- New clues about vitamin D functions in the nervous system.
- Stimulation of neurogenesis and synaptogenesis by bilobalide and quercetin via common final pathway in hippocampal neurons.
- Pyramidal Neurons Are Generated from Oligodendroglial Progenitor Cells in Adult Piriform Cortex.
- Mechanisms underlying fatigue: a voxel-based morphometric study of chronic fatigue syndrome.
Okada T, Tanaka M, Kuratsune H, Watanabe Y, Sadato N.
- Therapeutic potential of neurogenesis for prevention and recovery from Alzheimer's disease: allopregnanolone as a proof of concept neurogenic agent. Brinton RD, Wang JM.
- Brain foods: the effects of nutrients on brain function.

What is methylation? (A basic description)

2010-05-16T08:42:00.000-07:00

Dysfunctional methylation and low glutathione play a part in many chronic illnesses including CFS. Here i have written a basic description of what exactly methylation is along with useful tests that can be run to see if there are any problems.

Introduction
B12 and Folate share an overlapping metabolism so they are often spoken about together. They are essentially required for 2 things in the body, DNA synthesis, and methylation. The first accounts for the haematological changes seen in a b12/folate deficiency, the latter (which this article focuses on) for the neurological changes.

Methylation is one of the most common metabolic functions of the body, occurring in the order of a billion times per second. It is the process by which a methyl group (a carbon atom and 3 hydrogen atoms, or CH3) is transfered from one molecule (a methyl donor) to another (which becomes 'methylated'). In doing so this activates/controls various biochemical pathways and reactions in the body, influencing such things as:

- Growth & repair (mylein, phospholipids, epigenetics)
- Brain chemicals (neurotransmitters)
- Hormones (thyroid, adrenal, melatonin)
- Energy (co-q10, carnitine)
- Detoxification (sulfur metabolism, glutathione, redox)
- Immunity (T-cells, autoimmunity, histamine, TH1/TH2 balance, viral DNA, NK cell function)
- Etc...

The Methylation Cycle
The main methyl donor in the body is called SAMe (s-adenosylmethionine). Levels of SAMe are maintained by a basic cellular biochemical cycle, called the methylation cycle. This cycle is basically concerned with recycling SAMe, and keeping its level consistant. Once SAMe has donated its methyl group, it is converted into homocysteine which has to then be recycled back to SAMe (SAMe --> SAH --> homocysteine --> methionine --> SAMe). This recycling is performed by an enzyme (called methionine synthase, or MS) which is powered by an active form of B12 (methylcobalamin) and also requires an active form of folate (5-methyl-THF) to act upon.

Adjacent Pathways (Folate & Glutathione)
The methylation cycle links up with other cycles and pathways in the body like the folate cycle (required for DNA/RNA synthesis) and transsulfuration pathway, which leads to glutathione synthesis. Glutathione (GSH) is a hugely important molecule that is vital for phase 2 liver and cellular detoxification, and often thought to be the most important antioxidant in the body. Autism and CFS research has linked dysfunctional methylation with low GSH, and shown that correcting methylation normalises GSH levels [1-4].

Testing methylation function
Below are some tests that can help access methylation status:

1. The 'Methylation panel', available from vitamin dignostics in the US or Netherlands. This is the current gold standard test for assessing methylation and glutathione, it directly measures many methylation related markers in serum (active folates, B12, reduced/oxidised glutathione, SAMe/SAH, adenosine). It is possible to have issues show up on this test, whilst some of the tests below appear normal, this is because the tests below are mostly indirect measurements of B12/folate deficiency.

2. The MAP (metabolic analysis profile), available from genova diagnostics in the US or Europe. This is a urine test and very easy to do at home. The important methylation markers measured are MMA (measure of adenosylcobalamin) and FIGLU (measure of THF). Also a blood or urine AA (amino acid profile) is useful to access methionine levels. Some people with CFS have poor protein digestion and are low on amino acids, this will also hinder methlyation which relies upon good methionine levels amongst others.

3. If you cant get or afford the above tests, then any form of glutathione (GSH) measurement such as the 'Full GST' profile offered by Acumen lab in the uk is also useful. If glutathione is chronically low then you could have have methylation problems. Although it should be noted that a normal rbc GSH result is not always conclusive, since it dosent always reflect overall glutathione status. Serum GSH/GSSG such as that offered by vitamin diagnostics is thought to be superior.

4. If you have high homocysteine, then this implies B12, folate and/or B6 deficiency. If you have had full blood counts run and you have raised or even slightly raised MCV or RDW then this can imply B12/Folate deficiency and thus methylation problems. Also a low WBC (white blood cell count) could be due to folate deficiency (although there are other potential causes) and so could imply methylation problems too. For detailed information about the hematological effects of B12/Folate deficiency go here.

Treatment
CFS researcher Rich Van Konyenburg has devised a theory for the pathogenesis of CFS called the GD-MCB (glutathione depletion-methylation cycle block)[5]. It is based upon the common finding of low glutathione status in CFS patients, and observations made from the methylation research in autism, which showed the connection between dysfunctional methylation and low glutathione. His 'simplifed protocol' is centered around active forms of folate and B12, and has been proven effective in normalising glutathione levels and methylation parameters in a CFS clinical study[4], which lead to very significant symptom improvement. Many other practitioners and clinics also use similar protocols.

Research
1. Efficacy of methylcobalamin and folinic acid treatment on glutathione redox status in children with autism.
2. Abnormal Transmethylation/transsulfuration Metabolism and DNA Hypomethylation Among Parents of Children with Autism.
3. Metabolic biomarkers of increased oxidative stress and impaired methylation capacity in children with autism.
4. Treatment Study of Methylation Cycle Support in Patients with Chronic Fatigue Syndrome and Fibromyalgia.
5. http://aboutmecfs.org/Trt/TrtGSHIntro.aspx

Cadmium toxicity (summary of related research)

2010-05-16T08:16:00.000-07:00

Introduction
Cadmium (Cd) seems to be the main metal I have in my system. I think its mainly come from cigarrette smoke, which i had MCS-type reactions to before becoming ill. Below is research showing some of the metabolic effects and mechansims of Cd toxicity, or specifically cadmium chloride. I have mainly focused on oxidative stress and detoxification related studies, but i will hopefully go further into the mitochondrial side of things in the future. Some of the Cd studies referenced observe similar toxic effects and metabolic disturbances from other heavy metals like mercury, arsenic, aluminium, and nickel. Finally most of the studies are carried out over a time frame ranging from 12hrs to a month, and for most I only have access to the abstracts not the full study.

Research summary
Glutathione is the first line of defense against Cd (4,26), before metallothionein. Cd induces oxidative stress (31,43) through indirect mechansims, by inhibiting antioxidant enzymes. This leads to increased reactive oxygen species such as the superoxide ion, hydroxyl radicals, and hydrogen peroxide (31).

In vivo, lower concentrations of Cd cause GSH (reduced glutathione) induction (40), while higher levels deplete GSH and protein-bound thiol (SH) groups (18,31,40). Cd inhibits GSH-PX (10,13,14,15,16,17,19, 25) and GR (glutathione reductase) (2,6,9,18,60), and lowers SOD (17,19) and Catalyse activity (16,19).

Cd inducts protein kinase C (31,43) and nuclear factor-κB (31,61,62). Cd binds to G6PD (46) which in turn decreases enzyme activity (2,18,39,41,43,44,46). G6PD the key rate-limiting enzyme in the pentose phosphate pathway (HMP shunt), which is required for the production of ribose-5-phosphate (nucleic acid synthesis --> dna), and NAD(P)H (energy & redox) (45). Research suggests lowered NAD(P)H may be the mechanism responsible for the lowering of GSH-PX and GR activity in Cd toxicity (2,41,43), since they both require NAD(P)H for GSSG (oxidised glutathione) reduction.

The toxicity threashold of Cd is greatly afftected by nutritional status and overall capacity of the involved enzymes (26). Se supplementation prevents Cd induced oxidative stress by restoring GSH-PX function (6,10,14,15,17,19,21,27,28). Ascorbic acid (37), lipoic acid (33), melatonin (20,38), zinc (35,63) and vitamin E (34, 36) also provide protection against cadmium toxicity.

Cd can increase glutamate/aspartate based neurotoxicity by inhibiting the GLAST enzyme (11,20,21) and lower gaba and taurine in the brain (7,49,50,51). Cd disrupts mitochondrial function (20,30,47,48), can lower serum magnesium and increase urine loss (29), and interfers with thyroid function (32). Cd is very similar to zinc and can displace it an enzyme binding sites (23,24). Cd inhibits endothelial nitric oxide synthase and decreases NO levels (52,53,54,55), and can cause hypertension (56,57,58,59).

Searched terms
cadmium glutathione, cadmium metallothionein, cadmium gsh-px, cadmium glutamate, cadmium neurotoxicity, cadmium zinc, cadmium G6PDH, cadmium mitochondria, cadmium gaba, cadmium hypertension, cadmium NOS, cadmium nitric oxide, cadmium NF-kB.

References
1. http://www.inchem.org/documents/jecfa/jecmono/v46je11.htm#_46112200a
2. Glutathione Status and Cadmium Neurotoxicity: Studies in Discrete Brain Regions of Growing Rats. GIRJA S. SHUKLA, R. S. SRIVASTAVA and S. V. CHANDRA
3. Cadmium neurotoxicity Marisela Méndez-Armentaa, , and Camilo Ríosb
4. Glutathione, a first line of defense against cadmium toxicity RK Singhal, ME Anderson and A Meister
5. Metallothionein synthesis and degradation: relationship to cadmium metabolism. R J Cousins
6. Inhibition of glutathione reductase by cadmium ion in some rabbit tissues and the protective role of dietary selenium.
7. Cadmium chloride exposure modifies amino acid daily pattern in the mediobasal hypothalamus in adult male rat
A. Caride *, B. Fernández-Pérez, T. Cabaleiro, G. Bernárdez, A. Lafuente
8. HEAVY METAL-INDUCED CHANGES IN THE GLUTATHIONE LEVELS AND GLUTATHIONE REDUCTASE/GLUTATHIONE S-TRANSFERASE ACTIVITIES IN THE LIVER OF MALE MICE Author: Salah A. Sheweita
9. Interaction of glutathione reductase with heavy metal: the binding of Hg(II) or Cd(II) to the reduced enzyme affects both the redox dithiol pair and the flavin.Picaud T, Desbois A.
10. Effect of selenium supplementation on the influence of cadmium on glutathione and glutathione peroxidase system in mouse liver L. Jamba, B. Nehru, M.P. Bansal *
11. Inhibitory regulation of glutamate aspartate transporter (GLAST) expression in astrocytes by cadmium-induced calcium influx.Liu YP, Yang CS, Tzeng SF.
12.Possible role of glutamate, aspartate, glutamine, GABA or taurine on cadmium toxicity on the hypothalamic pituitary axis activity in adult male rats A. Lafuente1 and A.I. Esquifino2
13.Effect of fluorine, selenium and cadmium on anti-oxidase and microelements in rat's body. Mou S, Qin S, Hu Q, Duan X.
14. Effect of chronic cadmium exposure on glutathione S-transferase and glutathione peroxidase activities in rhesus monkey: the role of selenium. Sidhu M, Sharma M, Bhatia M, Awasthi YC, Nath R.
15. Some Metabolic Interrelationships Between Toxic Levels of Cadmium and Nontoxic Levels of Selenium Fed to Rats1
S. A. Meyer2, W. A. House3 and R. M. Welch
16. Selenium supplementation during cadmium exposure: Changes in antioxidant enzymes and the ultrastructure of the kidney L. Jamba, B. Nehru, M.P. Bansal *
17. COMBINED THERAPY WITH ANTIOXIDANTS AGAINST CADMIUM INDUCED TESTICULAR DYSFUNCTION IN RABBITS
Magda M. ElTohamy
18. Consequences of cadmium toxicity in rat hepatocytes: effects of cadmium on the glutathione-peroxidase system. L Müller
19. Effect of chronic cadmium exposure on antioxidant defense system in some tissues of rats: protective effect of selenium.
Ognjanović BI, Marković SD, Pavlović SZ, Zikić RV, Stajn AS, Saicić ZS.
20. MELATONIN AND CADMIUM TOXICITY Lafuente A*, Cabaleiro T, Caride A, Romero A.
http://ejeafche.uvigo.es/index.php?option=com_docman&task=doc_view&gid=446
21. Alternate cadmium exposure differentially affects the content of gamma-aminobutyric acid (GABA) and taurine within the hypothalamus, median eminence, striatum and prefrontal cortex of male rats.
Esquifino AI, Seara R, Fernández-Rey E, Lafuente A.
22. Effect of ethanol on cadmium uptake and metabolism of zinc and copper in rats exposed to cadmium.
Author Sharma G; Sandhir R; Nath R; Gill K
23. Effect of replacement of "zinc finger zinc" on estrogen receptor DNA interactions.
Author Predki PF; Sarkar B
24. Laboratory evaluations. richard s lord.
25. Changes in trace elements contents of renal cells in cadmium poisoning]
Author Long M; Zhao J; Wang S
26. Effects of fasting on cadmium toxicity, glutathione metabolism, and metallothionein synthesis in rats.
Author Shimizu M; Morita S
27. The protective effect of simultaneous selenium administration on acute cadmium toxicity and metallothionein
Author Ohta H; Imamiya S; Yoshikawa H
28. Cadmium induced lipid peroxidation in rat testes and protection by selenium.
Yiin SJ, Chern CL, Sheu JY, Lin TH
29. Contribution to interaction between magnesium and toxic metals: the effect of prolonged cadmium intoxication on magnesium metabolism in rabbits.
Author Soldatovi´c D; Matovi´c V; Vujanovi´c D; Stojanovi´c Z
30. Cadmium-induced oxidative cellular damage in human fetal lung fibroblasts (MRC-5 cells). Yang CF, Shen HM, Shen Y, Zhuang ZX, Ong CN
31. Oxidative mechanisms in the toxicity of chromium and cadmium ions.
Stohs SJ, Bagchi D, Hassoun E, Bagchi M.
32. http://www.ithyroid.com/cadmium.htm & http://www.ithyroid.com/metallothionein.htm
33. Relationship between glutathione and DL alpha-lipoic acid against cadmium-induced hepatotoxicity. Sumathi R, Baskaran G, Varalakshmi P
34. Cadmium and iron accumulation in rat lens after cigarette smoke exposure and the effect of vitamin E (alpha-tocopherol) treatment.
Author Avunduk AM; Yardimci S; Avunduk MC; Kurnaz L
35. Zinc amelioration of cadmium toxicity on preimplantation mouse zygotes in vitro.
Author Yu HS; Chan ST
36. Cadmium induced thyroid dysfunction in chicken: hepatic type I iodothyronine 5'-monodeiodinase activity and role of lipid peroxidation.
Author Gupta P; Kar A
37. Effect of L-ascorbic acid pretreatment on cadmium toxicity in the male Fischer (F344/NCr) rat.
Author Shiraishi N; Uno H; Waalkes MP
38. Effects of Selenium with Vitamin E and Melatonin on Cadmium-Induced Oxidative Damage in Rat Liver and Kidneys
Haki Kara, AydÄ±n Cevik, Vahit Konar, Alpaslan Dayangac and Kadir Servi
39. Effects of cadmium and zinc ions on purified lamb kidney cortex glucose-6-phosphate dehydrogenase activity
Authors: Berivan Tandogan a; Nuray N. Ulusu a
40. Cadmium and mercury cause an oxidative stress-induced endothelial dysfunction
Matthew B. Wolf1 and John W. Baynes2
41. Effect of cadmium on glutathione metabolism and glucose 6-phosphate dehydrogenase in rat tissues : role of vitamin E and selenium
SARKAR S. (1) ; YADAV P. (1) ; BHATNAGAR D. (2) ;
42. Mitochondrial NADP+-Dependent Isocitrate Dehydrogenase Protects Cadmium-Induced Apoptosis
In Sup Kil, Seoung Woo Shin, Hyun Seok Yeo, Young Sup Lee, and Jeen-Woo Park
43. Mediation of cadmium-induced oxidative damage and glucose-6-phosphate dehydrogenase expression through glutathione depletion.
44. In vitro effects of cadmium and arsenite on glutathione peroxidase, aspartate and alanine aminotransferases, cholinesterase and glucose-6-phosphate dehydrogenase activities in blood. Authors F Z Sheabar, S Yannai
45. http://en.wikipedia.org/wiki/Glucose-6-phosphate_dehydrogenase
46. Inhibition of Human Erythrocyte Glucose 6-Phosphate Dehydrogenase by Cadmium, Nickel and Aluminium
B. Haghighi* and D. Ilghari
47. Cadmium directly induced the opening of membrane permeability pore of mitochondria
M Li, T Xia, CS Jiang, LJ Li, JL Fu, ZC Zhou
48. http://www.mitochondrial.net/showcitationlist.php?mth=Cadmium&redirect=yes&terms=cadmium+mitochondria
49. Cadmium exposure disrupts GABA and taurine regulation of prolactin secretion in adult male rats. Caride A, Fernández-Pérez B, Cabaleiroa T, Esquifino AI, Lafuente A.
50. Toxic effects of cadmium on GABA and taurine content in different brain areas of adult male rats
LAFUENTE A. ; GONZALEZ-CARRACEDO A. ; CABALEIRO T. ; ROMERO A. ; ESQUIFINO A. I. ;
51. Effects of oral cadmium exposure through puberty on plasma prolactin and gonadotropin levels and amino acid contents in various brain areas in pubertal
male rats. LAFUENTE A. ; ESQUIFINO A. I.
52.Cadmium induced endothelial dysfunction: consequence of defective migratory pattern of endothelial cells in association with poor nitric oxide availability under cadmium challenge.Kolluru GK, Tamilarasan KP, Geetha Priya S, Durgha NP, Chatterjee S.
53.Cadmium reduces nitric oxide production by impairing phosphorylation of endothelial nitric oxide synthase.
Majumder S, Muley A, Kolluru GK, Saurabh S, Tamilarasan KP, Chandrasekhar S, Reddy HB, Purohit S, Chatterjee S.
54. Cadmium attenuates bradykinin-driven nitric oxide production by interplaying with the localization pattern of endothelial nitric oxide synthase.
Majumder S, Gupta R, Reddy H, Sinha S, Muley A, Kolluru GK, Chatterjee S.
55. Impairment of endothelium-dependent vasorelaxation in cadmium-hypertensive rats
O. Gökalp
56. Multiple linear regression analysis of hypertrophy, calcium and cadmium in hypertensive and non-hypertensive states
57. Cadmium as an Environmental Factor of Hypertension in Animals: New Perspectives on Mechanisms
M.V. Varoni1 , D. Palomba1, S. Gianorso1 and V. Anania1
58. Cadmium: Hypertension Induction and Lead Mobilization. Hubert L. Walker and Henry A. Moses
59. Cadmium Exposure and Hypertension in the 1999â€“2004 National Health and Nutrition Examination Survey (NHANES). Maria Tellez-Plaza, Ana Navas-Acien, Ciprian M. Crainiceanu, and Eliseo Guallar.
60.Inhibition kinetics of sheep brain glutathione reductase by cadmium ion.
61. Cadmium induces Interleukin-8 production via NF-κB activation in the human intestinal epithelial cell, Caco-2
62. Cadmium-induced apoptosis in rat kidney epithelial cells involves decrease in nuclear factor-kappa B activity
63. CHRONIC CADMIUM TOXICITY TO SPERM OF HEAVY CIGARETTE SMOKERS: IMMUNOMODULATION BY ZINC