Pravastatin Affects Artery Walls

Pravastatin Directly Affects Artery Walls in Monkeys

Pravastatin has been shown in three different large studies to substantially reduce the risk of heart attack and stroke. As a cholesterol-lowering drug, pravastatin was assumed by many to work primarily by lowering cholesterol levels. A new study suggests its benefits may result in part from the drug's direct effect on artery wall function.

A research team from North Carolina fed 32 monkeys a high-fat diet for 2 years. Then they put all of the monkeys on a low-fat diet and 14 of them on pravastatin as well for another 2 years. Researchers found that the concentrations of total cholesterol and the good HDL cholesterol remained similar in both groups of monkeys, Dr. J. Koudy Williams of Wake Forest University in Winston-Salem and co-workers report in the March Journal of the American College of Cardiology.

The team was not surprised to find similar cholesterol levels in the two groups, since the study was designed so that both groups of monkeys would have similar cholesterol levels at the beginning and during the study. The objective of the study was to examine the drug's effects on the artery wall.

After performing angiograms on the monkeys, the team found that the amount of plaque in the artery walls also grew the same amount in both sets of monkeys. However, the plaque in the monkeys on pravastatin was not as calcified and also had better dilation of the arterial wall, which improves blood flow in the vessels.

The authors conclude that the direct effects of pravastatin on the artery wall may account in part for the drug's reduction in the incidence of coronary events and strokes in humans.

Because the statin drugs all inhibit cholesterol synthesis and lower LDL cholesterol levels in the blood, the understandable tendency is to assume that this is all they do. However, studies in the test tube have demonstrated other effects of statin drugs and differences among the statins in some of these effects. The study reported above is the first to demonstrate the concept that pravastatin has effects on the vessel wall that are "independent" of (not directly due to) its ability to lower cholesterol. It did not compare pravastatin to any other statins and therefore comparative statements cannot be made. Nevertheless, this demonstrates that there may be more going on than we realize with some statins that is working to alter plaque and make it less likely to cause cardiovascular events. Much more research is needed before we fully understand these effects.

SOURCE: Williams, J. Koudy, "Pravastatin Has Cholesterol-Lowering Independent Effects on the Artery Wall of Atherosclerotic Monkeys", Journal of American College of Cardiology,