Antioxidant-Amino Acid Mix Shields Blood Vessels

Source: asia.reuters.com

A cocktail of antioxidants mixed with an amino acid may protect blood vessels from inflammation and the buildup of plaque, a preliminary study suggests.

According to the report, antioxidants and L-arginine, an amino acid, protected the cells of human blood vessels from the wear and tear of fluid rushing by.

Branch points, areas where two vessels meet, are particularly vulnerable because they are exposed to turbulent shear-stress, a type of force imposed by the flow of blood that can cause inflammation and plaque build up leading to atherosclerosis, or hardening of the arteries.

Shear-stress can also increase damage from free radicals, compounds that can cause varying degrees of damage to cells, researchers report in the online early edition of the Proceedings of the National Academy of Sciences.

To investigate if antioxidants and L-arginine might prevent this type of damage, researchers exposed human cells to different fluid flow forces inside a culture dish.

High shear-stress caused cells to produce inflammatory compounds. However, fewer dangerous compounds were produced when cells were coated with antioxidants and L-arginine. These substances also caused the cells to produce eNOS (endothelial nitric oxide synthase), an enzyme that allows vessels to expand and prevents blood from clotting.

Antioxidants have been shown to squelch free radicals while L-arginine is a precursor of nitric oxide, a compound that helps the inner lining of blood vessels to dilate.

In a second experiment, researchers demonstrated that these compounds reduced the damage caused by shear-stress in mice bred to have high cholesterol.

"These results demonstrate that atherogenic effects induced by turbulent shear-stress can be prevented by co-treatment with antioxidants and L-arginine," Dr. Louis J. Ignarro from the University of California in Los Angeles and colleagues conclude.

SOURCE: Proceedings of the National Academy of Sciences 2003;10.1073.

Date: 12-Dec-2008