Jan. 17, 2003 A UCLA research team has discovered that a popular health supplement and antioxidant vitamins may help prevent atherosclerosis, or blockage of the blood vessels. The findings are reported in the Jan. 13 online edition of the Proceedings of the National Academy of Sciences.
"Our findings suggest that people who take dietary supplements of L-arginine, an amino acid, and antioxidants, such as vitamins C and E, might be at a lower risk for atherosclerosis and heart disease," said Dr. Louis J. Ignarro, a 1998 Nobel laureate in medicine and UCLA professor of molecular and medical pharmacology. "This is significant because cardiovascular disease is still the No. 1 cause of death in the United States."
The early lesions and cholesterol deposits that mark atherosclerosis first develop where blood vessels branch in different directions. Blood rushing around these tight corners constantly exposes cells to a pounding force, causing inflammation. As the inflamed blood vessels narrow, plaques build up inside, blocking blood flow and often leading to serious disease, such as stroke and heart attacks.
"Atherosclerotic plaques act like trash caught in a river bend, impeding the flow," Ignarro said. "But our research shows that treatment with antioxidants and L-arginine may prevent blood vessel inflammation and subsequent damage."
Ignarro's lab exposed human cells in a culture dish to varying forces of fluid flow and found that high shear stress induced inflammatory molecules. When the scientists added antioxidants and L-arginine to the cells, the production of harmful molecules decreased. In addition, this step increased production of eNOS, a molecule that promotes dilation of the blood vessels and prevents clotting.
The UCLA team also showed that combining L-arginine and antioxidants blunted the damaging effects of shear stress in a strain of mice bred with high cholesterol levels.
"It's likely that L-arginine and the antioxidants act synergistically to reduce the levels of inflammatory molecules and increase eNOS levels," Ignarro said. "Although the experiments were conducted in mice, we believe that these observations may predict the same outcome in patients who suffer from atherosclerosis and heart disease."
Co-authors included Sharon Williams Ignarro and Wulf Palinski from UCLA; Fiolmena de Nigris, Giacomo Sica and Claudio Napoli from the University of Naples; and Lilach Lerman and Amir Lerman from the Mayo Clinic.
The National Institutes of Health and the Mayo Foundation supported the research.
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