Week of June 21, 2003; Vol. 163, No. 25

Double Duty: Diabetes drug protects reopened heart vessels

Nathan Seppa, Science News

link to article; restricted access

A drug normally prescribed to hold blood sugar in check provides an unexpected benefit to heart patients, a new study from South Korea finds. In people who have undergone the blood vessel–opening procedure called angioplasty, the diabetes drug limits the propensity of vessels to close again, a chronic problem.

Moreover, this study and one done in the United States show that the drug, rosiglitazone, lowers blood concentrations of C-reactive protein, a compound that's been linked to heart problems.

Rosiglitazone, marketed as Avandia by GlaxoSmithKline of Philadelphia, is currently prescribed for type II, or adult-onset, diabetes because it helps insulin regulate how the body burns sugars (SN: 4/14/01, p. 238: Available to subscribers at http://www.sciencenews.org/20010414/bob17.asp).

To test the drug's effect on reopened blood vessels, the Korean researchers identified 95 people, average age 60, with type II diabetes who were slated to receive angioplasty in coronary arteries. All the patients received pills to control high blood sugar. About half also got daily oral doses of rosiglitazone, while the others got a placebo. Both regimens started at the time of the angioplasty, a procedure in which the obstructed vessel is opened with a balloon-tipped catheter. The doctors also propped the vessels open by inserting mesh cylinders called stents.

After 6 months, 21 of 48 patients getting the placebo showed vessel blockage of at least 50 percent. In contrast, only 5 of 47 people getting rosiglitazone had that much obstruction, Sunghee Choi of Yonsei University College of Medicine in Seoul reported in New Orleans at a meeting of the American Diabetes Association this week.

The findings suggest the drug's benefits extend well beyond insulin regulation, she says.

Choi also noted that concentrations of C-reactive protein in patients getting the placebo were more than double those in the group getting rosiglitazone. C-reactive protein is elevated in people at high risk of heart attacks (SN: 4/20/02, p. 244: Available to subscribers at http://www.sciencenews.org/20020420/fob4.asp). Other studies have hinted at a link between C-reactive protein and diabetes (SN: 8/31/02, p. 136: http://www.sciencenews.org/20020831/bob9.asp).

James W. Chu of Santa Clara Valley Medical Center in San Jose, Calif., reported at the same conference that his team gave rosiglitazone for 3 months to 29 people—half of whom had mild type II diabetes. The others had insulin resistance, a precursor condition to diabetes, although they were outwardly healthy. In both groups, the drug significantly lowered C-reactive protein concentrations in blood.

Because other studies have linked C-reactive protein to inflammation, the two new studies suggest that quelling inflammation—and thus slowing a rush of cells to the site of angioplasty inside a blood vessel—is central to rosiglitazone's effects against vessel blockage, Choi says.

While Choi's work represents "a fascinating study," it needs to be replicated in a larger group, says Richard Kahn, chief scientific and medical officer at the American Diabetes Association in Alexandria, Va.

Heart disease is the largest killer of people with diabetes. These studies represent steps toward "a unifying hypothesis" that will ultimately reveal the biological mechanisms linking diabetes, heart disease, and inflammation, Kahn predicts.