He's found a key vasodilator that is degraded in hypertension and the potential for developing drugs that prevent organ damage in these patients.

"In every form of hypertension, except pulmonary hypertension, which is limited to the lungs, there is a change in kidney function so the kidneys cannot excrete the proper amount of salt and water at a normal blood pressure," said Dr. John D. Imig, renal vascular biologist at the MCG Vascular Biology Center.

"In fact, a change in kidney function has to occur before you can get the increase in blood pressure," Dr. Imig said. Indeed, researchers such as Dr. Imig are finding increasing evidence that the kidneys, which regulate sodium and water volume in the body, are a primary controller of blood pressure . "If you give a patient with hypertension who is on kidney dialysis a good kidney from a normotensive individual, all of the sudden, (his) blood pressure is controlled," he said.

Whichever comes first, hypertension-related kidney disease results in a breakdown in the extensive network where thousand of tiny filters called glomeruli connect to tubules that carry excess salt, water and toxins out of the kidneys so they can be excreted in the urine. As Dr. Imig looks over an image of a damaged kidney, the sclerosis and inflammation is readily apparent. Tiny glomeruli eventually die and the kidneys stop working.

Despite the large number of antihypertensive drugs on the market, the incidence of kidney damage and end-stage renal disease in these patients keeps going up, Dr. Imig said. Most of the drugs, in fact, do target the kidneys. Diuretics reduce the fluid and salt volume they must handle and ACE inhibitors and angiotensin receptor blockers block the action of the vasoconstrictor, angiotenin 2, which is released by the kidneys.

Dr
'"/>

Contact: Toni Baker
tbaker@mail.mcg.edu
706-721-4421
Medical College of Georgia
19-Jun-2002