Reducing Blood Pressure in Kidneys Found to Lessen Risk to Diabetics

The risk of kidney damage among diabetics could be significantly lowered by using drugs to reduce blood pressure inside the organ, a group of Japanese doctors said Wednesday.

Impaired kidney functioning and eventual failure are among the most dangerous side effects of diabetes. Doctors can often spot such kidney problems by the presence of proteins in urine.

According to a report in the New England Journal of Medicine, levels of protein in the urine of kidney-damaged diabetics dropped in a group of patients given captopril, originally used to reduce high blood pressure during long-term kidney dialysis.

Theory Bolstered

The findings of doctors at Sendai Shakaihoken Hospital in Sendai, Japan, bolsters the theory that increased blood pressure within the kidney--and not abnormal blood chemistry--helps create the condition called proteinuria among diabetics.

“That’s really very impressive,” said Dr. Harold Rifkin, president of the American Diabetes Assn. “I don’t know what it will ultimately do, but it is something that should be looked into further.”

Dr. Barry M. Brenner, director of the renal division at Brigham and Women’s Hospital and a professor of medicine at Harvard Medical School, said he is not surprised by the findings at Sendai.

“It raises the possibility that simple measures to prevent the development of intrarenal hypertension will have great therapeutic value over the long run,” he said.

Function of Kidneys

The kidney, acting as a filter, strains usable proteins from the body’s liquid waste before passing the unwanted chemicals on to the bladder.

The organ’s minute strainers, or glomeruli, can be damaged if blood is forced through them at too high a pressure, leading to proteinuria, or the presence of usable proteins in the urine, doctors say.

“In the present study, we observed a significant decrease in urinary protein excretion after captopril was administered, without significant changes in systemic blood pressure or blood glucose concentration,” the Japanese doctors said.