THURSDAY, Aug. 30, 2001 (HealthDayNews) -- An aspirin a day is now a commonly accepted way to prevent heart attacks. But could it also ward off diabetes?
Research in rodents finds aspirin-like drugs shield cells from the ravages of inflammation and help reduce their resistance to insulin. The compounds also appear to stimulate tissue in the pancreas to make more insulin, the hormone that helps the body convert sugar to energy.
Insulin-resistant diabetes, also known as adult-onset or Type II diabetes, affects roughly 14 million Americans, a number that is rising as more people become dangerously overweight.
Aspirin has a long but murky history in diabetes care. Nearly a century ago, doctors noticed that high doses of the drug reduced the concentrations of blood sugar, or glucose, in the urine of diabetics. And in the middle of the last century scientists found that short courses of aspirin treatment improved the ability of patients to handle their blood sugar.
Researchers initially concluded that aspirin somehow spurred the secretion of insulin. But recent work, including the latest study, which appears in the Aug. 31 issue of Science, suggests a different role for the drug.
Researchers led by Dr. Steven Shoelson of Harvard's Joslin Diabetes Center gave large doses of aspirin and a related drug called sodium salicylate to obese mice and rats with impaired insulin sensitivity. Over the next three to four weeks, the animals' blood glucose concentrations and their insulin sensitivity improved. So too did the animals' blood fat levels, which were dangerously high before treatment.
"Improving the metabolic control in diabetics will improve the long-term consequences" of insulin insensitivity, Shoelson says. "We can certainly conclude that the complications will be better if we get better control of the glucose and" blood fats.
Other painkillers, such as naproxen and ibuprofen, didn't affect insulin sensitivity, the researchers say. Those drugs target inflammatory enzymes called cyclo oxygenases, including cox-1 and cox-2. While aspirin does, too, it also blocks another inflammatory enzyme known as IKK-beta, which has the additional role of diminishing cells' sensitivity to insulin. Thus, Shoelson's group says aspirin and related molecules can reverse insulin insensitivity while other anti-inflammatory drugs do not.
The study supports another paper, published this month in the Journal of Clinical Investigation, in which Shoelson and his colleagues found that large doses of salicylate prevent insulin resistance in mice on a high-fat diet by blocking IKK-beta. Taken together, he says the studies underscore the potential importance of aspirin as a therapy to treat -- or perhaps even to prevent -- Type II diabetes.
The work carries major baggage, though. The doses of salicylate the researchers used are tens of times higher than what people take on a daily basis to reduce their risk of heart attacks, and well above even a short-term course for pain relief. In such large amounts aspirin is toxic and can cause severe bleeding.
But Shoelson says his group is working on a novel form of aspirin that's safer on the gastric tract. "It's not available today for diabetics, but that is where we're going," he says.
Dr. R. Paul Robertson, a diabetes expert and scientific director of the Pacific Northwest Research Institute in Seattle, has been among the pioneers in the study of aspirin's effects on diabetes. In the 1970s, Robertson and other researchers found that sodium salicylate has "a profound effect" on stimulating the pancreas to make more insulin.
Robertson says he's "excited" by the latest work because "it says there are two targets" for aspirin-like drugs: insulin production and insulin sensitivity. Since diabetes is a disease that requires the "double hit" of both problems, tackling each will be more effective than aiming at one alone, he says.
However, Robertson rejects the notion that salicylate's ability to inhibit cox enzymes isn't a major factor in their effect on insulin. In a 1999 paper, he and his colleagues showed that certain cox-2 inhibitors -- which include the new arthritis drugs Celebrex and Vioxx -- protect insulin producing cells from inflammation. And more recently, Robertson's group found that sodium salicylate does, too, by blocking cox-2 and another inflammatory chemical.
What To Do
The research is preliminary, so don't take it as a cue to swallow aspirin by the handful to ward off diabetes.
To learn more about the disease, visit the American Diabetes Association or the Joslin Diabetes Center.
For more on obesity and how to control your weight, check the National Institutes of Health.
