SATURDAY, April 2, 2005 (HealthDay News) -- There's more evidence statin drugs, which include popular medications like Lipitor, Pravachol and Zocor, prevent heart attack and stroke by means other than lowering blood cholesterol.
A new study in diabetic rats suggests that statin treatment also prevents or reverses damage to the delicate endothelial cells that line arteries, according to researchers from the Medical College of Georgia, in Augusta.
"The statins are probably producing these effects in a couple of ways," said co-researcher Dr. Robert Caldwell, professor and chair of pharmacology and toxicology at the college. "One is by reducing production of highly oxidative substances. Another was to reduce the inflammation of the vessels."
The Georgia researchers, led by postdoctoral fellow Guochuan Ma, were to present their findings Saturday at the annual meeting of the American Society for Pharmacology and Experimental Therapeutics, in San Diego.
The study was prompted by a finding from the Heart Protection Study, the largest-every study of cholesterol-lowering medications. Researchers in that study found that diabetics who took a daily dose of simvistatin (Zocor) were 27 percent less likely to have a first heart attack, and 24 percent less likely to have a stroke, than those who did not take the drug -- regardless of their blood cholesterol or sugar levels.
In the Augusta study, rats bred to become diabetic received 5 milligrams a day of Zocor. As expected, these mice displayed lower cholesterol levels. However, they also showed reductions in destructive oxidizing molecules within their arteries, which widened in a healthy, normal fashion, allowing proper blood flow.
In contrast, rats that did not receive Zocor displayed higher levels of these dangerous, reactive molecules and greater arterial rigidity.
The cholesterol-lowering effect of the drug also contributed to the protection of the artery lining, Caldwell said.
The animal studies are being extended because "we'd like to learn more about the role of statins in reducing inflammation," he said. "We really don't know why."
Even as laboratory work goes on, "clinical use is beginning," he added.
"Clinical studies show improvement in cardiovascular function independent of cholesterol reduction," Caldwell said. "We definitely see an increase in kidney function, a reduction of edema [swelling] and of inflammation in the eye and heart."
It's been known for some time that statins "have this fairly profound effect on endothelial function," said Dr. Steven E. Nissen, a cardiologist at the Cleveland Clinic who has done work on the subject. "I suspect it's why we see beneficial effects in clinical trials, reduced morbidity and mortality in just a few days."
There's an ongoing debate about exactly which of statins' beneficial effects are the most important in terms of reducing cardiovascular risk, Nissen said. He and his colleagues reported a study earlier this year indicating that the anti-inflammatory action of the drugs played a major protective role.
Find out more on statins and how they work at the National Heart, Lung and Blood Institute.