Air Pollution, High-Fat Diet Cause Atherosclerosis in Laboratory Mice

Fat Diet

Test results with laboratory mice show a direct cause-and-effect link between exposure to fine particle air pollution and the development of atherosclerosis, commonly known as hardening of the arteries. Mice that were fed a high-fat diet and exposed to air with fine particles had 1.5 times more plaque production than mice fed the same diet and exposed to clean filtered air.

Plaque, a fatty deposit on the inner lining of the blood vessels, can predispose individuals to conditions such as heart attacks and strokes. The fine particle exposure also led to increased inflammation of the artery walls and reduced function of the artery wall's inner lining.

The National Institute of Environmental Health Sciences, part of the federal National Institutes of Health, and the U.S. Environmental Protection Agency provided funding to researchers at the Mount Sinai School of Medicine and the New York University School of Medicine for the two-year study. The study results are published in the December 21, 2005 issue of the Journal of the American Medical Association.

The study showed that the combination of fine particle pollution and high-fat diet can promote the development of atherosclerosis, and may explain why people who live in highly polluted areas have a higher risk of heart disease. The findings are also important because the fine particle concentrations used in the study were well within the range of concentrations found in the air around major metropolitan areas.

The researchers did not observe significant differences in plaque production and artery wall inflammation in fine particle-exposed mice given the normal diet. However, among mice given clean air, those on the high-fat diet had greater plaque production and artery wall inflammation than those given the normal diet. These results suggest that both diet and fine particle pollution contributed to the development of atherosclerosis in the mice.

"This is one of the first studies to demonstrate measurable changes in plaque production and artery inflammation following exposure to fine particle matter," said NIEHS Director David A. Schwartz, M.D. "These findings have important implications for the long-term impact of fine particle air pollution on urban populations."

Fine particle pollution consists of microscopic particles of dust and soot less than 2.5 microns in diameter