Smooth muscle cells may hold key.

• Position: Coronary Disease

A basic mechanism by which smooth muscle cells that line blood vessels can grow--sometimes abnormally--has been discovered by researchers at the University of Texas Southwestern Medical Center, Dallas, suggesting methods of treatment for a number of coronary diseases. Abnormal growth of cells inside blood vessels is involved in hypertension, coronary artery disease, tumors called leiosarcomas, and various other conditions.

"By understanding this detailed mechanism, it is now possible to begin to design therapies to interfere with it and thereby potentially prevent various vascular disorders in humans," maintains Eric Olson, chairman of Molecular Biology.

There are three types of muscles in the body--skeletal, cardiac, and smooth. Smooth cells make up the stomach, intestine, blood vessels, and other organs. Unlike the skeletal and cardiac muscles, smooth muscle cells either can rest in their final form, which allows vessels to contract, or can divide into new cells.

Researchers have known about several signals that can stop smooth muscle cells from dividing and enable them to contract, but little is understood about how this cascade of interactions works. The protein...