How blood flow patterns help protect against heart disease

The frictional force and pressure of blood flowing through the heart's main arteries may stimulate cell changes that ultimately protect the body against atherosclerosis, or what's commonly known as "hardening of the arteries," University of Rochester Medical Center researchers have discovered.

Understanding the significance of blood flow and how it makes the cells of arteries resistant to some types of heart disease is a highly active area of research. A new study on the topic will be published Tuesday, May 15, 2001, in the Proceedings of the National Academy of Sciences, by Bradford C. Berk, M.D., Ph.D., and colleagues at the University's Center for Cardiovascular Research. Berk is director of the center and the Charles A. Dewey professor and chairman of the Department of Medicine at Strong Memorial Hospital.

Advanced study of blood flow patterns may lead to better drug therapy for atherosclerosis. Already, research in this area has resulted in two popular and common drug treatments ƒ{ nitrates, which reduce symptoms of chest pain, and Viagra, which treats impotence. Both drugs work by tricking the body into generating more blood flow.

Berk and his colleagues were trying to understand why plaques containing cholesterol accumulate in certain sections of the arteries, like silt piling up along a riverbank. High-risk areas seemed to be linked with turbulent blood flow due to irregular stress or strain on the blood vessel wall, whereas low-risk areas experience a steady flow that seemed to protect against atherosclerosis.

The team, which includes Wang Min, Ph.D., assistant professor at the Center for Cardiovascular Research, also studied the molecules in cells that control inflammation. Moreover, they examined how blood flow patterns might regulate the activity of inflammatory cytokines and white blood cells that initiate and stimulate atherosclerosis.

In the laboratory, the researchers grew endothelial cells, the cells that line the lumens of blood vessels. Normal functioning of the endothelial cells is critical to prevent atherosclerosis. Then, using sophisticated mechanical devices, experiments were created to examine how blood flow regulates cell function. They found that endothelial cells lined up parallel to the direction of blood flow. In addition, the aligned cells showed less inflammation.