Type 2 diabetes may be significantly delayed or prevented through medication that takes the load off of the body's delicate insulin-producing cells, according to a study released today by researchers at the Keck School of Medicine of the University of Southern California.
They presented their findings at the American Diabetes Association's 65th Scientific Sessions.
The Pioglitazone in Prevention of Diabetes (PIPOD) study tested whether the drug pioglitazone could protect women who had had gestational diabetes-a temporary form of diabetes during pregnancy-from developing type 2 diabetes later, explains study presenter Thomas A. Buchanan, M.D., professor of medicine, obstetrics and gynecology and physiology and biophysics at the Keck School.
Although most women with gestational diabetes do not remain diabetic right after delivery, they do commonly remain resistant to their insulin, and 30 to 50 percent of them develop type 2 diabetes within a few years after pregnancy. Because of that, studying women with gestational diabetes is useful for researchers seeking to understand diabetes and develop ways to prevent it.
In the study, researchers provided pioglitazone for three years to 89 women who had had gestational diabetes and who had already participated in their diabetes prevention study called TRIPOD, which used the drug troglitazone. Troglitazone reduced diabetes risk from 12 percent a year to only 5 percent a year. However, troglitazone was removed from use in 2000 because it caused rare but severe liver damage in those with type 2 diabetes.
For PIPOD, researchers used pioglitazone (also called Actos), which works similarly to troglitazone but is safe for the liver, to see if the diabetes rate would remain low. It did, less than 5 percent each year. Moreover, among those women who remained diabetes-free, beta-cell function did not change while the women were taking pioglitazone. Beta cells produce insulin.
As was true in the TRIPOD study, protection from diabetes in PIPOD was closely associated with reduced stress on the beta cells that results when physicians treat insulin resistance, Buchanan says.
"This study shows that our initial findings for diabetes prevention with troglitazone apply not only to this class of drugs-thiazolidinediones-but to the general mechanisms of reducing stress on beta cells by treating insulin resistance," Buchanan says. "Theoretically, weight loss and some other drugs may be able to do the same thing."
Buchanan explains that the body's cells need sugar, or glucose, for energy. Insulin helps cells grab glucose from the blood. But when cells grow resistant to insulin, beta cells must create more insulin to make up that resistance. Researchers believe that in some people, beta cells eventually buckle under the heavy load and wear out. Their failure leads to type 2 diabetes.
Pioglitazone makes the body's cells more sensitive to insulin, reducing beta cells' workload.