2008 Woodie Awards
Abnormal membrane protein causes hypertension
Issue date: 12/6/07
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High blood pressure in the U.S. has reached epidemic proportions. According to the Centers for Disease Control and Prevention, 30 percent of adult Americans have it, 277,000 Americans died from it in 2002 and 90 percent of middle-aged adults will develop it before they die.
Obvious need has pushed scientists to better understand high blood pressure's causes and to find some effective therapies.
To this end, a group of Hopkins researchers, led by Rajini Rao at the School of Medicine, believe they've identified a gene linked to the most common form of high blood pressure.
Most of the time, high blood pressure - the technical term is hypertension - is called "essential" or "primary."
Unlike a related disorder called secondary hypertension, which usually arises from some other underlying condition, essential hypertension has no specific, treatable cause and is generally thought to be influenced by both behavioral choices and genetic predispositions.
Hypertension is a problem of balance. For their cells to function properly, all animals - from the lowliest nematode to the haughtiest human - have to maintain a balance between fluids and electrolytes (dissolved, positively-charged ions) in and around every cell.
Primarily, this is accomplished by transporting electrolytes from inside the cells out into the bloodstream or vice versa.
It's not surprising, then, that people with essential hypertension almost always have malfunctions in electrolyte transport, while those with secondary hypertension are generally normal.
What's more, a particular type of transport - called sodium-lithium countertransport (SLC) - is strikingly correlated with essential hypertension.
Indeed, the presence of increased SLC activity in red blood cells has been relied on for almost 20 years as a tool in diagnosing essential hypertension.
During SLC, one lithium ion from inside a cell is exchanged for one sodium ion from outside the cell. This is mediated by a specialized protein called an antiporter, which is inserted in the cell's membrane.
Obvious need has pushed scientists to better understand high blood pressure's causes and to find some effective therapies.
To this end, a group of Hopkins researchers, led by Rajini Rao at the School of Medicine, believe they've identified a gene linked to the most common form of high blood pressure.
Most of the time, high blood pressure - the technical term is hypertension - is called "essential" or "primary."
Unlike a related disorder called secondary hypertension, which usually arises from some other underlying condition, essential hypertension has no specific, treatable cause and is generally thought to be influenced by both behavioral choices and genetic predispositions.
Hypertension is a problem of balance. For their cells to function properly, all animals - from the lowliest nematode to the haughtiest human - have to maintain a balance between fluids and electrolytes (dissolved, positively-charged ions) in and around every cell.
Primarily, this is accomplished by transporting electrolytes from inside the cells out into the bloodstream or vice versa.
It's not surprising, then, that people with essential hypertension almost always have malfunctions in electrolyte transport, while those with secondary hypertension are generally normal.
What's more, a particular type of transport - called sodium-lithium countertransport (SLC) - is strikingly correlated with essential hypertension.
Indeed, the presence of increased SLC activity in red blood cells has been relied on for almost 20 years as a tool in diagnosing essential hypertension.
During SLC, one lithium ion from inside a cell is exchanged for one sodium ion from outside the cell. This is mediated by a specialized protein called an antiporter, which is inserted in the cell's membrane.
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