Diabetes
Moderate Use May Avert Failure of Type 2 Diabetes Drugs
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Drugs widely used to treat type 2 diabetes may be more likely to keep working if they are used in moderation, researchers at Washington University School of Medicine in St. Louis have found in a study using an animal model.
The drugs, sulfonylureas, help type 2 diabetics make more insulin, improving control of blood sugar levels. But in most patients the effects of sulfonylureas are lost after several years of use, causing insulin secretion to shut down. This typically forces patients to switch to regular insulin injections.
“Why this happens isn’t clear yet, but we’ve found what may be cause for hope,” says senior author Colin G. Nichols, Ph.D., Carl F. Cori Professor and professor of cell biology and physiology. “We’ve shown in a mouse model that whatever causes this shutdown doesn’t kill the insulin-making beta cells of the pancreas or stop them from making insulin. Instead, it somehow stops them from secreting insulin.”
Fasting may cut risks of heart disease, diabetes
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Routine periodic fasting, which is practiced by some members of the Church of Jesus Christ of Latter-day Saints (LDS), may reduce the risks of heart disease and diabetes, according to findings from the Intermountain Heart Collaborative Study conducted in Utah.
The Utah population has one of the lowest rates of death from cardiovascular disease in the U.S., likely due to the lifestyle of members of the LDS—particularly low rates of smoking—lead investigator Dr. Benjamin D. Horne told Reuters Health.
However, as smoking rates have dropped in other states, Utah still has one of the lowest heart disease death rates, Horne said. “There should have been some convergence of disease rates because Utah’s smoking prevalence can’t decline as much as other states,’ but that is not what we have observed.”
Vision loss more common in people with diabetes
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Visual impairment appears to be more common in people with diabetes than in those without the disease, according to a report in the October issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
Approximately 14.6 million Americans had diagnosed diabetes mellitus in 2005 and another 6.2 million had undiagnosed diabetes, according to background information in the article. It is estimated that the number of individuals with diagnosed diabetes will increase to 48.3 million by 2050. “Diabetic retinopathy [damage to the retina caused by diabetes], one of the most common microvascular complications of diabetes, is considered to be one of the major causes of blindness and low vision,” the authors write. Although studies suggest that controlling glucose and blood pressure have reduced the rate of retinal diseases, other ocular conditions suffered by diabetic patients, such as cataract and glaucoma, may increase the risk of visual impairment. Additionally, decreased vision caused by an abnormal shape of the cornea is also common among people with diabetes.
New Target for Obesity-Related Insulin Resistance, Type 2 Diabetes
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Building on mounting evidence that implicates infection-fighting cells found in obese fat tissue in the growing problem of insulin resistance and Type 2 diabetes, researchers at the University of California, San Diego, School of Medicine have identified a particular subset of cells that are linked to obesity-associated insulin resistance, and that offer a promising new target for the treatment of diabetes. They showed that depletion of these cells, called CD11c-positive, in obese mice resulted in a reversal of obesity-associated insulin resistance.
The study, led by Jaap Neels, Ph.D., formerly of UC San Diego School of Medicine and now at the Université de Nice-Sophia Antipolis, and Jerrold Olefsky, M.D., Distinguished Professor of Medicine and Associate Dean for Scientific Affairs at UC San Diego, will be published in the October 8 issue of Cell Metabolism.
Obese adipose, or fat, tissue is characterized by the presence of macrophages, specialized cells that usually fight infection. Adipose tissue macrophages (ATMs) accumulate in fat tissue as body weight increases. Growing evidence shows that ATMs are a significant contributor to inflammation in obesity – inflammation that leads to insulin resistance, resulting in Type 2 diabetes.
People with Type 2 Diabetes Can Put Fatty Livers on a Diet with Moderate Exercise
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Weekly bouts of moderate aerobic exercise on a bike or treadmill, or a brisk walk, combined with some weightlifting, may cut down levels of fat in the liver by up to 40 percent in people with type 2 diabetes, a study by physical fitness experts at Johns Hopkins shows.
According to researchers, who will present their findings on Sept. 18 at the annual meeting of the American Association of Cardiovascular and Pulmonary Rehabilitation, in Indianapolis, high liver fat levels are common among people with type 2 diabetes and contribute to heart disease risk.
The study’s lead investigator, exercise physiologist Kerry Stewart, Ed.D., says the rise in the number of people with nonalcoholic fatty liver, mostly due to obesity, signals “a dark trend” because the disease, also called hepatic steatosis, may lead to cirrhosis and subsequent liver failure and transplantation, even cancer, as well as increased risk of diabetes-related heart disease.
Higher Urinary Levels of Commonly Used Chemical Linked With CVD, Diabetes
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Higher levels of urinary Bisphenol A (BPA), a chemical compound commonly used in plastic packaging for food and beverages, is associated with cardiovascular disease, type 2 diabetes and liver-enzyme abnormalities, according to a study in the September 17 issue of JAMA. This study is being released early to coincide with a Food and Drug Administration (FDA) hearing on BPA.
BPA is one of the world’s highest production–volume chemicals, with more than two million metric tons produced worldwide in 2003 and annual increase in demand of 6 percent to 10 percent annually, according to background information in the article. It is used in plastics in many consumer products. “Widespread and continuous exposure to BPA, primarily through food but also through drinking water, dental sealants, dermal exposure, and inhalation of household dusts, is evident from the presence of detectable levels of BPA in more than 90 percent of the U.S. population,” the authors write. Evidence of adverse effects in animals has created concern over low-level chronic exposures in humans, but there is little data of sufficient statistical power to detect low-dose effects. This is the first study of associations with BPA levels in a large population, and it explores “normal” levels of BPA exposure.
David Melzer, M.B., Ph.D., of Peninsula Medical School, Exeter, U.K., and colleagues examined associations between urinary BPA concentrations and the health status of adults, using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004. The survey included 1,455 adults, age 18 through 74 years, with measured urinary BPA concentrations.
Diabetes linked to poor weight loss with surgery
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Obese individuals with diabetes lose less weight with gastric bypass surgery than do their peers without diabetes, researchers at the University of California, San Francisco, report.
With gastric bypass surgery, a small stomach pouch is created, which limits food intake by making the patient feel full sooner after eating than he or she otherwise would. In addition, a portion of bowel is connected to the stomach, effectively bypassing the first portion of the bowel where most food absorption occurs.
The new findings, which appear in the Archives of Surgery, also indicate that a bigger stomach pouch leads to inferior weight loss.
Early diabetes treatment key for long term health
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People with diabetes given intensive drug treatment soon after diagnosis are healthier when they grow older, even if they become less rigorous about controlling their blood sugar later on, British researchers said on Wednesday.
This means it may be important to prescribe diabetes drugs early, even for people just diagnosed with type 2 diabetes, instead of trying to get them to diet and exercise first, the researchers reported in the New England Journal of Medicine.
“We now know not only that good glucose control from the time type 2 diabetes is diagnosed reduces the rate of diabetic complications but also that this early intervention leads to sustained benefits in the longer term,” Rury Holman of Oxford University, who led the study, said in a statement.
Hepatitis C patients may have abnormal blood sugar
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Nearly two thirds of patients with chronic hepatitis C infection may have abnormal blood sugar levels, according to a report in the American Journal of Gastroenterology.
Blood sugar, or “glucose,” abnormalities “are common and easily underestimated among patients with chronic hepatitis C infection,” Dr. Ming-Lung Yu from Kaohsiung Medical University, Taiwan told Reuters Health. Careful evaluation for undetected glucose abnormalities is “essential” in caring for chronic hepatitis C patients.
Yu and colleagues compared the prevalence and characteristics of glucose abnormalities among 522 chronic hepatitis C patients and a comparison group of 447 without hepatitis C infection (“controls”), based on the results of an oral glucose tolerance test.
How gastric bypass rapidly reverses diabetes symptoms
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A report in the September Cell Metabolism, a publication of Cell Press, offers new evidence to explain why those who undergo gastric bypass surgery often show greater control of their diabetes symptoms within days. It also helps to explain why lap-band surgery doesn’t offer the same instant gratification. By studying mice that have undergone both procedures, the researchers show that changes in the intestine are the key.
In addition to removing about two-thirds of the stomach, gastric bypass in effect produces a “double intestine,” said Gilles Mithieux of Institut National de la Sante et de la Recherche Medicale in France. The portion closest to the stomach is taken out of the loop so that it receives no nutrients. The segment normally farther down is then attached directly to the stomach, where it receives all the nutrients coming in.
In both cases, those positional changes ramp up production of blood sugar by the small intestine, Mithieux said. He noted that fasting normally induces blood sugar production by the upper small intestine. By placing the lower small intestine, which doesn’t normally produce much glucose, in close proximity to the stomach, it starts to act more like the upper portion.
Obesity not a red flag for spotting diabetes
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Obese people with diabetes are just as likely to go undiagnosed as their slimmer peers with the disease, Harvard Medical School researchers report.
It’s well recognized that obesity increases the likelihood of developing diabetes, yet “obesity does not increase the likelihood that an individual’s diabetes will be diagnosed,” Dr. Christina C. Wee and her colleagues from Harvard and Beth Israel Deaconess Medical Center in Boston report.
There is no consensus on who should be screened for diabetes, Wee and her team note in their report in the medical journal Diabetes Care. Early diagnosis of diabetes is particularly important for obese people, they add, because research shows they are less likely to be offered the preventive care that can help stave off serious complications of the disease.
High doses of vitamin D safe for children
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Giving school children very high doses of vitamin D is safe, and may be necessary to bring their blood levels of the nutrient up to the amount necessary for optimum bone growth and health, a new study shows.
Insufficiency in vitamin D is common in children around the world, but there is little data on how much supplementation kids need, or even how much vitamin D they should have in their blood, Dr. Ghada E.-Hajj Fuleihan of the American University of Beirut in Lebanon told Reuters Health. “In the pediatric literature, we don’t have a lot to guide us,” she said.
In a previous study, Fuleihan and colleagues found that giving 10- to 17-year-olds relatively high doses of vitamin D3 increased their bone mass and bone area, as well as lean mass. In the current study, they report on both the short- and long-term safety of high-dose supplementation.
Class of Diabetes Drugs Carries Significant Cardiovascular Risks
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A class of oral drugs used to treat type 2 diabetes may make heart failure worse, according to an editorial published online in Heart Wednesday by two Wake Forest University School of Medicine faculty members.
“We strongly recommend restrictions in the use of thiazolidinediones (the class of drugs) and question the rationale for leaving rosiglitazone on the market,” write Sonal Singh, M.D., M.P.H., assistant professor of internal medicine, and Curt D. Furberg, M.D., Ph.D., professor of public health sciences. Rosiglitazone and pioglitazone are the two major thiazolidinediones.
In the editorial Singh and Furberg say, “At this time, justification for use of thiazolidinediones is very weak to non-existent.”
Potential diabetes treatment selectively kills autoimmune cells from human patients
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In experiments using blood cells from human patients with diabetes and other autoimmune disorders, Massachusetts General Hospital (MGH) researchers have confirmed the mechanism behind a potential new therapy for type 1 diabetes. A team led by Denise Faustman, MD, PhD, director of the MGH Immunobiology Laboratory, showed that blocking a metabolic pathway regulating the immune system specifically eliminated immune cells that react against a patient’s own tissues.
Faustman and her colleagues previously discovered a technique that reversed type 1 disease in a mouse model. The current study, which will appear in the Proceedings of the National Academy of Sciences and has been released online, is the first demonstration of this strategy in human cells and supports the viability of a clinical trial that is currently underway.
“Our studies in mice showed that we could selectively kill the defective autoimmune cells that were destroying insulin-producing islets,” says Faustman. “These results show that the same selective destruction can occur in humans cells and connect what we saw in our animal studies with the protocol we are pursuing in our Phase I clinical trial.”
Low cholesterol associated with cancer in diabetics
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Low levels of LDL cholesterol as well as high levels are associated with cancer in patients with type 2 diabetes, found a prospective cohort study http://www.cmaj.ca/press/pg427.pdf published in CMAJ.
Researchers from the Hong Kong Institute of Diabetes and Obesity, the Li Ka Shing Institute of Health Sciences and The Chinese University of Hong Kong conducted a study of 6107 Chinese patients with type 2 diabetes and found a V-shaped risk relation between LDL cholesterol and cancer in patients not receiving statin therapy.
“LDL cholesterol levels below 2.80 mmol/L and levels of at least 3.90 mmol/L were both associated with markedly elevated risk of cancer among patients who did not use statins,” state Dr. Juliana Chan and coauthors.
