New insights into treatment of hypertension in black Americans

Dec 6 2005

Researchers have reported a possible explanation for the higher risk of heart disease and its complications among black Americans, along with a way of treating this condition.

Over the course of a three-year investigation, the findings of which were published in the American Heart Association journal, Circulation, researchers found important differences in the way that blood vessel constituents from black Americans produced an essential substance required for normal function, known as nitric oxide. This new study showed a clear link between increased levels of free radicals and lower production of a key substance that regulates blood pressure and preserves vascular health.

The findings also showed that this condition in black Americans could be significantly improved with a new generation beta-blocker known as nebivolol. Nebivolol was able to favorably enhance the levels of nitric oxide while simultaneously reducing oxidative stress, a known factor that damages the heart and blood vessels. The beneficial effects of nebivolol on the blood vessel function complement its beta-blockade properties.

"This is the first evidence that we can favorably enhance a key regulator of blood pressure in vessels from black Americans by stimulating the cells own enzymatic processes," explained investigator Dr. R. Preston Mason, PhD, faculty member and senior research staff scientist at Brigham & Women's Hospital, Harvard Medical School. Dr. Mason is also the President of Elucida Research in Beverly, MA. "Treatment of cells in the blood vessels from black Americans with nebivolol had the effect of markedly improving the release of nitric oxide, a promoter of vascular health that also preserves normal blood pressure. Nebivolol also reduced levels of free radicals in the cells."

These findings further address an important health care challenge in black Americans, a population that suffers a disproportionate incidence of cardiovascular disease. Black Americans are affected by certain forms of heart disease at a rate almost twice the rate of the corresponding white population and are more likely to die from it. Even after accounting for a variety of factors, including access to medical care and socioeconomic factors, studies in heart failure show that the mortality rate and the hospitalization rate for black Americans is significantly higher than for other Americans.

"This is an exciting development as it provides new insights into the treatment of cardiovascular risk factors, especially hypertension, in black Americans," said Dr. Mason. "This is the first evidence that a new generation beta-blocker may have the additional and specific benefit of preserving normal vascular health in this group of Americans that suffer disproportionately from cardiovascular disease."

The study can be accessed on-line at: http://www.ahajournals.org/