New Findings Provide Insight Into Treatment Of Hypertension In Mexican Americans

Main Category: Hypertension
Article Date: 08 Nov 2007 - 12:00 PDT

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Researchers have reported a possible explanation for lower rates of blood pressure control in Mexican Americans, along with a potential way of treating the condition. A new study showed that blood vessel cells from Mexican Americans had lower production of the natural blood vessel relaxant, nitric oxide (NO), in comparison to cells from non-Hispanic whites. NO is an essential substance in healthy blood vessels and is required for regulating normal blood pressure. The study also showed that treatment with nebivolol, a beta blocker, improved the availability of NO in the cells of Mexican Americans. The findings will be presented at the American Heart Association Annual Scientific Session in Orlando, Fla.

Researchers found important differences in the amount of NO produced in blood vessel cells from Mexican Americans. Baseline bioavailability of NO in Mexican American cells was 30 percent lower than in non-Hispanic white cells. Treatment with nebivolol enhanced NO bioavailability 57 percent in Mexican American cells and 20 percent in non-Hispanic white cells, eliminating interracial differences. The increased levels of NO were not seen in cells treated with atenolol, another beta blocker. The increase of NO in nebivolol-treated cells may be partially due to the drug's ability to increase levels of the enzyme NO synthase.

"These observations suggest a therapeutic role for agents that enhance the levels of nitric oxide, a key regulator of blood pressure, in vessels from Mexican Americans," explained lead author R. Preston Mason, PhD, faculty member and cell biologist at Harvard Medical School. Dr. Mason is also the President of Elucida Research in Beverly, Mass., which funded the study. "In our study, treatment of cells in the blood vessels from Mexican Americans with nebivolol markedly improved the release of NO."

These findings address an important health care challenge in Mexican Americans, a population that suffers a disproportionate incidence of hypertension and cardiovascular disease. The National Health and Nutrition Examination Survey (NHANES) reports that Hispanics have substantially lower rates of blood pressure control along with higher rates of cardiovascular disease, as compared to non-Hispanic whites. This increase in cardiovascular risk may be due, in part, to differences in the bioavailability of NO in blood vessels.

"This study provides exciting, new insights into the treatment of cardiovascular risk factors, especially hypertension, in Mexican Americans," said Dr. Mason. "This is important evidence that nebivolol may have the additional benefit of promoting normal vascular health in this group of Americans who suffer disproportionately from cardiovascular disease."

Nebivolol is a beta blocker that combines vasodilation with beta-1 selectivity. Nebivolol has been available outside the United States for a decade and Forest Laboratories licensed nebivolol in the U.S., where it is currently under review by the U.S. Food and Drug Administration for the treatment of hypertension.

Elucida Research LLC is a private laboratory in Beverly, Mass. dedicated to independent and innovative biomedical research. It was founded in 2000 by Dr. R. Preston Mason.

American Heart Association