Genetic clues to high blood pressure in African Americans

    African Americans develop high blood pressure more often and at earlier ages than white Americans.

    About 31 percent of all U.S. adults have high blood pressure, but the rate for Africans Americans is nearly a third higher: 40 percent.

    In the past, investigators have tried to measure the societal stress that African Americans experience, wondered if their kidneys somehow work differently, even hypothesized that inherited traits from African captives in North America predispose black Americans to hypertension.

    Michael Brown, an associate professor in the Department of Kinesiology at Temple University, is taking a different tack: He’s studying the cells the line the walls of blood vessels.

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    “What we are trying to do, and this is the very first step, is go down to the cell, try to understand some molecular events that are happening that may set up the conditions for hypertension in African Americans,” Brown said.

    Brown’s team nudged endothelial cells with an inflammation protein to mirror real world conditions that cause inflammation and an unhealthy condition called oxidative stress.

    In cells from African Americans, microparticles that indicate damage increased 90 percent. For Caucasians, that figure was just an 8 percent increase.

    “Some groups may need to pay more attention, be more vigilant if they have a higher susceptibility to certain conditions,” Brown said.

    No surprise, it’s the usual suspects–a sedentary lifestyle and high fat diet–that cause inflammation and oxidative stress.

    Healthy blood pressure is important because constricted, rigid blood vessels cause damage to the heart, brain and kidneys.

    In another study, the Temple University team simulated exercise in the lab.

    “When blood vessels are exposed to exercise they become very, very healthy, and they become protective of inflammation and oxidative stress,” Brown said.

    Wallace Johnson is a hypertension specialist at the University of Maryland School of Medicine. He says more and more researchers are studying out-of-whack responses to inflammation.

    “It would be sort of like if somebody told you: ‘Gee, I want a glass of water,’ and all you wanted was a small glass of cool water and they brought you in a bucket and started to pour it into a glass.

    The body can be damaged, overwhelmed, Johnson says, by decades of low-grade, chronic inflammation.

    This story is part of a project on health care in the states, a partnership between WHYY, NPR and Kaiser Health News.

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