Researchers at SUNY Downstate Medical Center in Brooklyn have determined that low levels of a protein in the blood is a predictor of cardiac death in patients with coronary artery disease.
In a group of men undergoing coronary angiography, low baseline levels of RANTES (Regulated upon Activation, Normal T-cell Expressed, and Secreted), also known as CCL5, were shown to be an independent predictor of cardiac mortality.
RANTES is a chemokine produced by a variety of cell types including blood platelets that has been implicated in atherosclerosis. Chemokines are naturally occuring human proteins that signal white blood cells to move in a specific direction, such as to an infection site.
Erdal Cavusoglu, MD, assistant professor of medicine at SUNY Downstate, and colleagues measured baseline RANTES levels in 389 male patients at a Veterans Affairs medical center. The patients were followed prospectively for the occurrence of cardiac mortality and myocardial infarction (heart attack). Results showed that patients with the lowest level of RANTES had the lowest survival rate, and those with the highest levels had the highest survival rates. This was also true for the diabetic subset of patients in the study.
The authors propose several potential explanations for this somewhat paradoxical observation, including potential upregulation of the RANTES receptor, the CCR5 receptor, which is known for its proatherosclerotic properties. Alternatively, lower levels of RANTES may simply reflect greater deposition of RANTES on atherosclerotic arteries with less circulating levels available for measurement by routine ELISA testing.