Inefficient metabolism within blood vessels may help drive atherosclerosis, or hardening of the arteries, a new study suggests.

While it's already known that smoking and high cholesterol levels contribute to vascular disease, these risk factors aren't present in some people with atherosclerosis.

Reporting in the May 26 issue of Nature, researchers at Washington University School of Medicine in St. Louis offer the first real evidence of another factor involved in atherosclerosis.

"For years, we've heard people say, 'Bad metabolism runs in my family.' Our study suggests 'bad' metabolism does lead to inflammation in blood vessel walls, and can contribute to heart attacks and strokes," Dr. Clay F. Semenkovich, a professor of medicine, cell biology and physiology, said in a prepared statement.

Traditionally, atherosclerosis has been viewed as a chronic inflammation resulting from vascular injury. In research with mice, Semenkovich and his colleagues found evidence to suggest the root cause of atherosclerosis may be mitochondrial problems in the cells of blood vessel walls.

Mice specially bred to overproduce a protein found in the walls of the heart's aorta, a major artery, developed both high blood pressure and atherosclerosis, the researchers report. Semenkovich speculates the protein change altered metabolic processes within the artery, stimulating disease.

The study may offer new targets for developing treatments for vascular disease, he added.