Early warning signs

Drug could cut risk of high blood pressure in youths

Sarah Brown, 21, said she never worried about heart disease.

 

"I know it is developing in the population," said the aspiring nurse at Augusta State University.

If researchers at the Georgia Prevention Institute at Georgia Health Sciences University are right about a potential drug intervention, she might never have to worry about it.

The research is aimed at treating prehypertension, which occurs in those whose blood pressure is above normal and are at risk of developing hypertension if nothing is done. Nearly a third -- 28 percent -- of Americans have prehypertension and 31 percent have high blood pressure, putting them at greater risk for strokes or heart attacks, according to the Centers for Disease Control and Prevention.

Prehypertension "is a huge problem," said Prevention Institute researcher Dr. Yanbin Dong. "It's a lot."

Often those patients are overweight or obese and sedentary, and they are advised to make lifestyle changes in order to lower their blood pressure. But two large-scale studies -- one in Germany and one in the U.S. -- have shown that giving an angiotensin II-receptor blocker to those patients could help delay the onset of hypertension. Another trial is under way in Brazil. All of those trials, however, were in middle-aged to older people.

The Georgia Prevention Institute is looking at what had once been an unimaginable problem -- prehypertension in adolescents and young adults, primarily in those who are overweight or obese. Brown is among a small group of patients who have been taking a drug called amiloride. It is designed to conserve potassium and block the reabsorption of sodium. Dong said it does this by blocking the epithelial sodium channel in kidney cells.

The same sodium channels have recently been discovered in vascular smooth muscle and endothelial cells, but their function in humans is not clear, according to an abstract written by Dong and internal medicine resident Dr. Samip Parikh. If the drug blocks the channel in the kidney, it should also block it elsewhere, Dong said.

In an initial study, the researchers found that administering the drug for four weeks lowered blood pressure and reduced the velocity of blood in peripheral arteries. If their theory is correct, the drug should have a beneficial effect beyond just lowering the blood pressure, Dong said. Also, the drugs are cheap and have a low incidence of side effects.

Brown has been on the drug for about four months and thinks it is helping.

"I believe my blood pressure is better," she said.

Dong says more study is needed. He is also hesitant about advocating for a pharmaceutical intervention when lifestyle changes are recommended.

"We ask them to lose weight, exercise more regularly, eat sensibly, go out to play, so on and so forth," Dong said. "(But) it is hard to change your lifestyle. It is hard to lose weight. It is not so hard to lose weight initially but harder to maintain your weight reduction. It is hard to change your eating habits."

Being obese or overweight cannot be traced to a single factor, Parikh said.

"It's a combination of lots of factors, like diet, exercise, genetics, environment, how their parents are doing," he said. "When we think about preventing, we have to take care of all of those factors. That's why it is really hard for them to actually meet the goal."

The solution could be unhooking obesity from its other health effects, Dong said.

"It's hard for them to change their habits. It's hard for them to lose weight," he said.

It is not so much accepting the problem as it is trying to do something about it, Dong said.

"Obesity has adverse consequences, it does. A lot of adverse consequences," he said. "But we have to face reality."