Cholesterol contributes to atherosclerosis - a condition that greatly increases the risk of heart attack and stroke - by suppressing the activity of a key protein that protects the heart and blood vessels, researchers at the Saint Louis University School of Medicine have found.
Their findings could lead to new therapies to treat or prevent heart disease – the leading cause of death in the United States – as well as answer key questions about other diseases associated with high cholesterol levels, including some types of cancer.
The study is published in an early online edition of the Journal of Cell Science (http://jcs.biologists.org).
“We believe these findings represent a significant and novel breakthrough in cardiovascular research,” said Jung San Huang, Ph.D., professor of biochemistry and molecular biology at the Saint Louis University School of Medicine and the study's lead researcher.
“This study gives us new insight into how cholesterol promotes atherosclerosis – and in turn, how it leads to heart attack and stroke,” Dr. Huang added. “This could give us important new tools in the fight against heart disease.”
It has long been known that high blood cholesterol is a key risk factor for developing atherosclerosis – sometimes called hardening of the arteries. The condition causes the arteries of the heart and other tissues to become damaged and narrowed, preventing blood from pumping through as it should and increasing the risk of heart attack and stroke.
Until now, however, the process by which cholesterol contributes to atherosclerosis has not been well understood.
Using an animal model, Chun-Lin Chen, a senior graduate student on Dr. Huang's research team, found that cholesterol limits the activity of a key protective protein called transforming growth factor-beta (TGF-beta). TGF-beta serves many important functions in the body; in the heart, it protects the aorta and other vessels from damage caused by a variety of factors, including hypertension and high blood cholesterol levels.