News

New trigger discovered for metabolic syndrome, a risk factor for diabetes

Janet Otsuki Kuo — Fri, 24 Feb 2012 20:15:47 +0000

People at risk for metabolic syndrome have elevated levels of a receptor triggering destructive inflammation that eventually lead to diabetes and heart disease, according to new research from University of California at Davis.

The researchers at UC Davis Medical Center focused their study on two Toll-like receptors (TLRs), called TLR2 and TLR4. These sensors on cells initiate a fast immune response to infections but also trigger harmful inflammation.

Past research has implicated TLR2 and TLR4 in the development of diabetes and heart disease.

The UC Davis study evaluated 90 people aged 21 to 70 years. Of the group, 49 of them had at least three features of metabolic syndrome – hypertension, low HDL-cholesterol, high triglycerides and obesity. Members of the control group had no more than two of these features.

Results of blood comparisons showed that the metabolic syndrome group had significantly higher levels of cell-surface receptor proteins TLR2 and TLR4 and messenger RNA than the control group.

The metabolic syndrome group also had higher levels of the master switch of inflammation in the nucleus, and a much higher concentration of immune “soldiers” in the blood, like cytokines, that create inflammation.

Researchers found that levels of free fatty acids were twice as high in the blood of people in the metabolic syndrome group. The levels of the product of gram-negative bacteria and endotoxin were three times as high as the control group. Both explain the raised levels of TLR4, in part.

According to UC Davis, patients can suppress TLR activity with weight loss and with diet, exercise and medicines that target TLR2 and TLR4. This might prove effective in treating heart disease, diabetes and other conditions linked to metabolic syndrome.

Metabolic syndrome is a cluster of cardio-metabolic risk factors. It is a high-risk state of obesity that increases the risk of developing diabetes at least five-fold and heart disease by two- to four-fold, according to UC Davis.

One third of American adults have metabolic syndrome, according to UC Davis.

The research was published in the February 22 issue of Diabetes Care.

Source: UC Davis Health System

Insulin production may continue decades after type 1 diabetes onset

Janet Otsuki Kuo — Thu, 23 Feb 2012 18:12:02 +0000

Insulin production may continue for decades after a diagnosis of type 1 diabetes, according to Massachusetts General Hospital. The research study appears in the March issue of the journal Diabetes Care.

The researchers also discovered that some type 1 diabetes patients have beta cell function even years after they believed they had lost pancreas function.

More than 180 patients with type 1 diabetes participated in the study. To test for beta cell function, scientists analyzed blood samples for C-peptide, an indicator of insulin secretion.

Results showed that C-peptide production continued to respond to blood glucose levels.

In addition, production could persist for decades after the onset of type 1 diabetes. For example, among participants living with the disease for 31 to 40 years, about 10 percent still produced C-peptide.

The study confirmed that the longer a person has type 1 diabetes, the lower the C-peptide levels. However, researchers discovered that the decline in C-peptide production is gradual and not sudden as traditionally believed for type 1 diabetes.

Researchers also found that beta cell function remained even at very low C-peptide levels.

“Our results contribute to a growing body of evidence suggesting there might be a longer window for therapeutic intervention in this disease,” said Denise Faustman, MD, PhD, associate professor of Medicine at Harvard Medical School and lead author of the study.

Researchers said that patients with low C-peptide levels or advanced disease might consider new therapies to preserve or encourage beta cell function and to prevent complications.

Type 1 diabetes is an autoimmune disease in which the body does not produce insulin. This form of the disease affects just 5 percent of all people living with diabetes. It's usually diagnosed in children and young adults.

Source: Massachusetts General Hospital, American Diabetes Association

Pancreatic hormone linked to severe heart damage in people with diabetes

Janet Otsuki Kuo — Tue, 21 Feb 2012 05:47:04 +0000

A pancreatic hormone called amylin is linked to severe heart damage in people with diabetes and obesity, according to a study conducted at the University of California at Davis.

Researchers found that diabetic and obese patients with heart failure had accumulated strings of proteins, fibers and plaques made of amylin in their hearts. Amylin is the hormone that produces the sensation of satiety after eating.

The UC Davis scientists also found through animal research that the collection of amylin in the heart leads to destruction and failure of the heart muscle.

“Amylin appears to be a stealth killer,” said Florin Despa, assistant professor of pharmacology at UC Davis and senior author of the study that appears in the February 17 issue of the journal Circulation Research.

The study compared normal and failing donated hearts of people undergoing heart-transplant surgery. The normal hearts of lean people had little or no amylin accumulation. Meanwhile, the failing hearts of obese and type 2 diabetes patients had extensive accumulation of amylin in protein strings called oligomers.

In addition, the non-failing hearts of overweight but not obese people also showed a smaller yet nonetheless abnormal buildup of amylin.

Controlling the amount of amylin in the blood could potentially prevent or reduce deaths from heart disease, according to the study.

“Drugs that block amylin from forming into toxic oligomers could significantly reduce the chances of heart failure,” said Despa.

The hormones amylin and insulin circulate together in the blood of healthy people. Amylin regulates gastric fluxes and the feeling of fullness, while the hormone insulin regulates carbohydrate and fat metabolism.

“There is only one amylin protein for every 100 insulin proteins in the blood, so it has been under the radar until recently,” said Despa.

Adults with diabetes have heart disease death rates about two to four times higher than adults without diabetes, according to the American Diabetes Association. Two out of three people with diabetes die from heart disease or stroke.

Sources: University of California at Davis, American Diabetes Association

image by Patrick J. Lynch, medical illustrator

Researchers identify new gene variants associated with type 2 diabetes risk

Janet Otsuki Kuo — Tue, 14 Feb 2012 18:55:31 +0000

The largest genetics study of its kind has identified new gene variants associated with risk for type 2 diabetes, according to The Children's Hospital of Philadelphia.

In all, researchers identified variants in four previously unknown genes associated with type 2 diabetes. They also discovered six new independent genetic signals in known type 2 diabetes genes.

The international study found that gene variants associated with type 2 diabetes risk cross multiple ethnic groups. Most studies until now were based on people of Caucasian ancestry.

Researchers from The Children's Hospital of Philadelphia and Massachusetts General Hospital and Harvard Medical School analyzed 39 previous studies of multiethnic populations. The study included more than 17,000 people with type 2 diabetes and 70,000 control subjects.

Researchers used a customized gene analysis tool to analyze 50,000 gene variants across 2,100 genes with known associations with cardiovascular and metabolic functions.

“Scientists have identified only about 10 percent of the generic variants contributing to type 2 diabetes, and most previous studies have been based on people of European ancestry,” said senior co-author Brendan J. Keating, PhD, of the Center for Applied Genomics at The Children's Hospital of Philadelphia.

Almost 40 gene variants have now been identified to raise or lower the risk of type 2 diabetes. The majority of gene variants remain undiscovered.

This study's genome-wide screening approach in large multi-ethnic samples should be effective in discovering additional diabetes gene variants relevant to multiple ethnic populations, Keating said.

The results of this study may focus attention on biological targets for developing medications to treat type 2 diabetes.

“As we continue to identify more genes associated with type 2 diabetes, we expect that further investigation of their specific biological functions will guide researchers toward new therapies for preventing and treating this disease,” said Keating.

The study appears in the online edition of American Journal of Human Genetics.

Source: The Children's Hospital of Philadelphia

Setting goals for specific daily servings improves dietary habits of diabetics

Janet Otsuki Kuo — Fri, 10 Feb 2012 23:30:31 +0000

Setting a specific goal to eat a certain number of daily servings of low-glycemic-index foods helps improve dietary habits of people with type 2 diabetes, according to research from Ohio State University.

Researchers learned that people can increase their consumption by almost two servings a day if they set that as a specific goal.

“We asked people to set goals because they motivate action,” said Carla Miller, associate professor at Ohio State University and the study’s lead author. “Telling people to ‘go out and do your best’ is not effective. It’s not specific enough, or targeted enough, or timely.”

Researchers interviewed the 35 participants with type 2 diabetes and set individual goals for them to eat either six or eight servings per day of foods low on the glycemic index.

After eight weeks, the group as a whole showed a significant average increase in their total daily servings of low-glycemic-index foods. They also showed a significant average decrease in caloric intake and overall dietary glycemic index.

Study participants ate about 500 fewer calories a day with goal setting. They also increased their intake of vegetables, fruits, nuts and seeds, which are all low-glycemic index foods.

Self efficacy
The confidence that participants felt about meeting these goals was linked to their ability to reach them, according to the study.

People who had more confidence, or self-efficacy, were more committed. Higher commitment levels led to a higher success rate of reaching their dietary goals.

Researchers learned after the eight-week study that most participants had confidence in meeting their goals because they were already eating at least six servings of low glycemic foods a day before the study began. Not all participants reached their goals, however.

“What we found is that those who felt more committed to the goal felt the goal was less difficult. And those who had a higher level of self-efficacy felt that the goal was less difficult,” said Miller. “Increasing levels of self-efficacy and increasing goal commitment are critical to achieving goal behavior.”

“One way to build self-efficacy is by helping people set a specific goal that is moderately difficult, action-oriented, and achievable in small successive steps. Then those people with higher self-efficacy feel the goal is less difficult, they are more committed, and they feel more satisfied in achieving the goal," Miller said. “That satisfaction helps them say, ‘Let's set the next higher goal.'"

Glycemic index
Foods with a low glycemic index are carbohydrates that are digested slowly. They are less likely to increase blood glucose levels than foods with a high glycemic index.

Foods that tend to slow digestion include vegetables, whole grains, dairy foods, nuts and seeds, beans, and fruit.

On a scale of 1 to 100, foods with an index of 55 or less are considered low glycemic foods. Foods with a point value of 100 are equivalent to pure glucose.

Results from the same study published last year showed that these same participants reduced their weight, body mass index, waist circumference and hemoglobin A1c value after increasing their intake of foods low on the glycemic index.

Source: Ohio State University

Insulin therapy increases pancreatic cancer risk

Janet Otsuki Kuo — Tue, 07 Feb 2012 18:53:18 +0000

Insulin therapy increases the risk of pancreatic cancer and overall cancer, according to research from the University of Maryland, Baltimore.

Researcher Zhiqiang Lu studied data from more than 230,000 patients in the United Kingdom on antidiabetic therapy. Lu found that the use of insulin alone or in combination with other oral agents was associated with an increased risk of cancer.

In particular, use of insulin alone increased the risk for pancreatic cancer by 88 percent. The study found that it increased the risk of colorectal cancer as well.

In addition, insulin with oral agents increased the risk of pancreatic cancer by 133 percent.

Lu explored the role of hemoglobin A1c (HbA1c) value in modifying the risk. HbA1c is a lab test that shows the average amount of glucose in the blood over three months.

His analysis showed that HbA1c appears to be a risk factor for pancreatic cancer, with abnormal levels increasing the risk by 38 percent. The risk posed by HbA1c value varies among different types of cancer.

Other factors that increase the risk of pancreatic cancer include premixed and intermediate-acting insulin, compared to short-acting insulin.

Diabetes, cancer link
It’s well documented that people with diabetes are at higher risk for some cancers than people without diabetes. Cancers of the pancreas, colon, breast, liver, uterus, and bladder occur more frequently in people with type 2 diabetes, according to Mayo Clinic.

Potential reasons for the link between diabetes and cancer include shared risk factors, hyperglycemia, and other metabolic abnormalities of type 2 diabetes that cause cancer, according to Mayo Clinic.

Shared risk factors include advanced age, obesity and overweight, physical inactivity, unhealthy diet, being male, excessive alcohol intake, ethnicity, and tobacco smoking.

Lower your risk
Losing weight is one recommendation by American Diabetes Association to lower the risk of cancer. Weight loss of just 7 percent of total weight has shown to make a significant difference in a person’s cancer risk.

Eating a healthy diet with plenty of fresh vegetables, fruits and whole grains is another recommendation. Low-fat or non-fat dairy products and lean meats are also sensible choices. Watching portion sizes is crucial.

Individuals should set a goal of getting physical activity 30 minutes a day, 5 days a week, according to American Diabetes Association.

Finally, quitting smoking can lower the risk of developing cancer.

Sources: University of Maryland, Mayo Clinic, American Diabetes Association

Poor diabetes control causes hearing loss, especially in women

Janet Otsuki Kuo — Fri, 03 Feb 2012 20:29:55 +0000

Poor diabetes control causes hearing loss in women as they age, according to research conducted by Henry Ford Hospital in Detroit.

The study found that women between the ages of 60 and 75 whose diabetes was poorly managed had worse hearing than women with well-controlled diabetes.

The women with well-controlled diabetes had hearing levels similar to those of non-diabetic women of the same age range.

Researchers also found significantly worse hearing in all women younger than 60 years of age with diabetes, even when the disease is well managed.

Men of all ages in the study had worse hearing loss compared to women in the study, regardless of whether or not they had diabetes.

The researchers analyzed pure tone average, which measures the hearing level at certain frequency, and speech recognition at different ages. In particular, they looked at the frequency at which most people speak and the higher frequencies used in music and alarms.

The records of almost 1,000 patients were used in the study. Patients were categorized by age, gender and whether or not their had diabetes. The study followed the guidelines set by the American Diabetes Association to define well-controlled or poorly controlled diabetes.

Glucose levels and hearing loss
Hearing loss is twice as common in people with diabetes compared to those without the disease, according to American Diabetes Association.

The rate of hearing loss is 30 percent higher in people with pre-diabetes than in people with normal blood glucose levels.

American Diabetes Association states that high glucose levels can damage the small blood vessels and nerves in the inner ear, causing hearing loss.

Signs of hearing loss include difficulty hearing in noisy places or hearing conversations in large groups, according to American Speech-Language-Hearing Association (ASHA).

Other signs may include difficulty hearing over the telephone, better hearing through one ear than the other, trouble understanding higher pitch sounds, thinking that other people are mumbling, or dizziness, pain or ringing in your ears.

Approximately 34.5 million people in the US have some type of hearing loss, according to American Diabetes Foundation. About 26 million people have diabetes and 79 million are believed to have pre-diabetes.

Sources: Henry Ford Hospital, American Speech-Language-Hearing Association, American Diabetes Association

Mechanism identified for how antipsychotic drugs cause diabetes

Janet Otsuki Kuo — Fri, 03 Feb 2012 17:05:42 +0000

Researchers have now identified the mechanism for how antipsychotic medications cause diabetes and obesity, according to Sanford-Burnham Medical Research Institute.

Researchers found that many antipsychotic drugs interfere with normal metabolism by activating a protein called SMAD3, an important part of the transforming growth factor beta (TGF?) pathway. This mechanism controls many cellular functions, including the production of insulin.

“We now believe that many antipsychotics cause obesity and diabetes because they trigger the TGF? pathway. Of all the drugs we tested, the only two that didn't activate the pathway were the ones that are known not to cause metabolic side effects,” said Fred Levine, MD, PhD, director of the Sanford Children's Health Research Center at Sanford-Burnham.

The scientific community has long associated antipsychotics with negative metabolic side effects, but the mechanism was unclear until now.

Antipsychotics are typically prescribed for bipolar disorder, schizophrenia and other behavior disorders. In 2008, roughly 14.3 million Americans were taking antipsychotics, according to Sanford-Burnham. These are among the most prescribed drugs in the US.

People who do not take antipsychotics also may experience dysfunction in the TGF? pathway and related health problems.

“It's known that people who have elevated TGF? levels are more prone to diabetes. So having a dysregulated TGF? pathway—whether caused by antipsychotics or through some other mechanism—is clearly a very bad thing,” said Levine.

“The fact that antipsychotics activate this pathway should be a big concern to pharmaceutical companies. We hope this new information will lead to the development of improved drugs,” he said.

Being overweight is a risk factor for developing diabetes. Other risk factors include family history, ethnicity, age, and physical inactivity.

The results of the research study were published on January 31 in the journal Molecular Psychiatry.

Source: Sanford-Burnham Medical Research Institute, National Institutes of Health

FDA approves once-weekly injection for type 2 diabetes

Janet Otsuki Kuo — Mon, 30 Jan 2012 16:53:27 +0000

The US Food and Drug Administration approved on Friday the first once-weekly injection that improves glycemic control in people with type 2 diabetes, according to a news release from Amylin Pharmaceuticals, Inc.

Amylin's injectable prescription medicine Bydureon provides a controlled release of exenatide throughout the week. It helps the body make its own insulin when needed and improves blood glucose levels in adults with type 2 diabetes.

Bydureon should be used with diet and exercise. Amylin does not recommended Bydureon as the first medication to treat diabetes.

Amylin plans to make Bydureon available in pharmacies nationwide in February. Patients can self-administer the suspension by subcutaneous injection.

The approval of Bydureon was based on results of a clinical trial as well as clinical experience with Byetta, Amylin's twice-daily form of exenatide that has been available in the US since June 2005.

In the 24-week clinical trial, patients taking Bydureon reduced A1C by 1.6 percentage points from baseline, according to Amylin. A1C is a measure of average blood sugar over three months. Patients also lost an average of 5.1 pounds during the trial program as well.

One adverse side effect noted in the trial included nausea by 14 percent of patients. Others included diarrhea, upper respiratory tract infection and injection site nodules. No major hypoglycemic events were noted.

Other common side effects are headache, vomiting, constipation, itching at the injection site, and indigestion.

Bydureon is not for people with type 1 diabetes or people with diabetic ketoacidosis. The drug is not recommended for use in children.

Exanatide has been associated with acute pancreatitis. Bydureon should not be used in people with a history of severe kidney problems as it may cause kidney problems and kidney failure.

People with type 2 diabetes should consult their treating physician to discuss their diabetes management plan.

Source: Amylin Pharmaceuticals, Inc.

Biochip tests saliva, not blood, for glucose

Janet Otsuki Kuo — Fri, 27 Jan 2012 18:05:55 +0000

A biochip under development can measure glucose levels in human saliva, according to Brown University.

The sensor may one day eliminate the need to draw blood to check glucose levels for the 26 million people in the US living with diabetes.

Engineers at Brown University etched thousands of plasmonic interferometers onto a biochip the size of a fingernail. Surface plasmonics involves the interaction of electrons and light.

“This is proof of concept that plasmonic interferometers can be used to detect molecules in low concentrations, using a footprint that is ten times smaller than a human hair,” said Domenico Pacifici, assistant professor of engineering and lead author of the research paper on the study. The paper is published in the journal Nano Letters.

Glucose in human saliva is about 100 times less concentrated than in human blood.

The sensor could one day be used to accurately measure concentrations of glucose in water as low as 0.36 milligrams per deciliter.

“It could be possible to use these biochips to carry out the screening of multiple biomarkers for individual patients, all at once and in parallel, with unprecedented sensitivity,” Pacifici said.

The technique could be used to detect other chemicals or substances at once using just one chip, according to Brown University. Substances could include anthrax or biological compounds.

Blood glucose monitoring
Blood glucose monitoring is a crucial tool for managing diabetes and preventing complications from the disease. It helps patients determine how their diet and exercise affect their blood glucose levels, how illness and stress can affect blood sugar, and when their blood sugar is dangerously high or low.

Glucose testing requires drawing a drop of blood by finger prick. The drop of blood is then placed on a disposable test strip and tested using a small electronic device that measures glucose levels.

The frequency of testing depends on the type of diabetes and the management plan designed by the treating physician. Some patients may test their blood glucose levels 3 times a day or more. However, some patients may avoid regular testing due to the inconvenience and discomfort of drawing blood.

Source: Brown University, Mayo Clinic