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Stop the Brain Drain

Antioxidants, blood pressure drugs may sharpen kidney patients' minds, says study

THURSDAY, Oct. 11, 2001 (HealthDayNews) -- Kidney failure doesn't affect just the kidneys. It can affect how sharp your brain is, too. Fortunately, new research says there may be ways to counteract that damage.

Physicians have long known that kidney failure patients often suffer neurological complications, like memory problems, but until now they didn't know exactly why it happened.

Researchers at the University of California (UC) at Irvine have found how brain cells are damaged by kidney disease, and they may have found a way to prevent that damage by using either antioxidants or blood-pressure-lowering medication.

"Chronic kidney disease affects the brain and the nerves. Even when treated, over time chronic, slow reductions in brain function occur," says one of the study's authors, Dr. Nick Vaziri, head of nephrology and hypertension at UC's College of Medicine. The ability to remember is diminished, and it also gets harder to do math, says Vaziri. Other possible neurological complications include sleep disorders, emotional instability, apathy, agitation and, in more advanced cases, even seizures and coma.

Currently 230,000 people in the United States have end-stage renal disease, and that number is increasing by 10 percent a year, says the National Kidney Foundation, which estimates the cost of treating kidney failure at $14.5 billion annually. Kidney disease has no cure; patients must either undergo dialysis or have a kidney transplant to survive.

Using rats whose kidneys were almost completely removed to mimic end-stage renal disease, Vaziri and his colleagues found that the animals had high levels of free radicals, molecules that alone or in combination with other body chemicals can damage cells. In kidney failure patients, free radicals damage the brain's cerebral cortex where "high level" thought occurs, the researchers say.

Based on other studies showing that antioxidants like vitamin C and beta carotene can reduce free radicals, Vaziri's team used them in the rats. One group of animals received no treatment, while another received a two-week course of powerful antioxidant therapy.

The researchers say the treated group had lower levels of damaged cells and lower blood pressure than the untreated group. To find out if lowering the blood pressure alone could reduce free radicals, the researchers treated some rats with a blood-pressure-lowering drug known as an ACE inhibitor. They found a marked improvement in those animals as well.

"This study needs to be replicated," says Dr. Joel Delfiner, chairman of the department of neurology at Nassau University Medical Center in East Meadow, N.Y. That "would give stronger evidence to trying antioxidant therapies for a variety of brain disorders," he says. Many diseases of the brain, like Alzheimer's, Huntington's and even stroke, share some of the same cellular changes as brain damage from kidney disease, says Delfiner.

The study's finding appear in the current issue of the Journal of the American Society of Nephrology.

What To Do

Vaziri says the study emphasizes the need for dialysis patients to eat a healthy diet rich in antioxidants, and to control their blood pressure. He says kidney disease patients should continue to take the vitamins prescribed by their physicians, but he does not recommend that anyone start taking large doses of antioxidants.

To learn more about antioxidants, go to Cornell University's Food and Nutrition Web site.

The National Institute of Diabetes and Digestive and Kidney Diseases offer this article about eating right while on dialysis.

SOURCES: Interviews with Nick Vaziri, M.D., professor of medicine, physiology and biophysics, head, nephrology and hypertension, University of California Irvine College of Medicine, Calif.; Joel Delfiner, M.D., chairperson, department of neurology, Nassau University Medical Center, East Meadow, N.Y., associate professor of clinical neurology, State University of New York at Stony Brook; September 2001 Journal of the American Society of Nephrology
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