Drug tested against kidney disease

SAN FRANCISCO (UPI): In results with important implications for the 275,000 Americans with polycystic kidney disease, researchers reported last week they found a drug blocked progression of the disorder in mice.

In laboratory tests, the scientists showed taxol -- a drug extracted from Pacific Yew tree bark and recently approved for ovarian, breast and lung cancers -- was effective in mice genetically predisposed to the kidney malady.

The University of California, Los Angeles, School of Medicine study, published in the British journal Nature, points to the first non-cancer application of taxol, which is to be tested on human kidney patients next year.

The most common hereditary kidney disorder, polycystic kidney disease occurs in one out of 800 people, who are born with thousands of microscopic cysts in their kidneys.

The cysts accumulate fluid and gradually balloon in size. Typically, the progressive disease destroys the organs in 30 to 50 years.

Since there is no known treatment to prevent the eventual kidney failure, patients ultimately require chronic dialysis or transplantation to survive.

The annual cost to Medicare for the dialysis alone tops $750 million annually, the doctors said.

The UCLA researchers tested a variety of drugs, using cells from the kidneys of diseased mice.

"Numerous drugs were tested, initially, none prevented cyst formation both in cells and in animal models," said David Woo, assistant professor of medicine at UCLA and lead author of the study.

"However, we discovered agents that interfere with the cell's cytoskeleton, or interior reinforcement system, including taxol, inhibited cyst formation in vitro."

Next, the researchers tested taxol in the affected mice.

"Mice that received weekly treatments of taxol have lived more than eight months, growing into healthy adulthood with minimal loss of kidney function," Woo said. "Untreated mice all died of kidney failure at one month of age."

Until now, little was known about the exact nature of the biochemical or genetic defects that lead to the disease.

"This study shows us a problem in the cytoskeleton system of kidney cells may play a central role in pathogenesis of the disease," Woo said.

The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health.