Photo: The study has implications for understanding heart disease in African Americans, according to lead researcher Randall Tackett, a professor in the College of Pharmacy. 
By Judy Purdy
Photo: The study has implications for understanding heart disease in African Americans, according to lead researcher Randall Tackett, a professor in the College of Pharmacy.
A recent study by a UGA scientist may help explain why American blacks have a higher incidence of cardiovascular disease than whites.
Bypass patients studied
The study of tissue from the saphenous vein (a vein in the leg) from heart-bypass patients suggests that blood vessels from African Americans generate almost twice as many free radicals as blood vessels from white patients. The finding has important implications for understanding the disease process in African Americans, and it suggests the therapeutic use of antioxidants such as vitamins C and E. The study was released at the American Heart Association's 70th Scientific Sessions earlier this month.
"The body produces free radicals, which are highly reactive molecules that circulate in the bloodstream and can attack body tissues such as the blood vessels and damage them," says Randall Tackett, professor of clinical and administrative sciences in the College of Pharmacy and the study's lead researcher. "Some free radicals, including one called superoxide, have been shown to interfere with the ability of blood vessels to vasodilate, or relax."
Constricted blood vessels reduce the flow of blood and raise blood pressure. When vessels in the heart are severely constricted or totally blocked, they can cause a heart attack.
"Free radicals also may play a role in the development of plaques such as occurs in atherosclerosis, or hardening of the arteries, by attacking the blood vessel walls, damaging them so they can't relax," Tackett says.
Bodily defenses
The body has several defenses against free radicals, including enzymes that scavenge free radicals such as superoxide, he says.
Tackett's study measured the generation of superoxide in saphenous vein segments of 18 blacks and 26 whites. Other research has demonstrated that free radicals play a role in cardiovascular diseases but no other studies have evaluated free radical production in African Americans.
Tackett's team also measured the levels of enzymes that scavenge free radicals to determine if these levels were different in African Americans. The enzyme levels were the same, and the researchers concluded that African Americans do not have an enhanced defense system to scavenge the increased production of free radicals.
Tackett's findings complement his team's earlier research on racial differences in blood vessels. A study reported three years ago showed blood vessels from African Americans have a reduced ability to dilate because of a lack of nitric oxide, a substance produced by the cells that line the blood vessels. Since superoxide can inactivate nitric oxide, an increase in superoxide production could help explain the reduced vasodilation reported earlier by the research team.
