April 11 (HealthDay News) -- Compounds called CFTR inhibitors show promise in slowing the progression of polycystic kidney disease (PKD), according to preliminary research conducted at the University of California, San Francisco, School of Medicine.

PKD is the most common kind of genetic kidney disease. Patients develop cysts on the kidneys, which progressively increase in size and number. As a result, the kidneys become enlarged, eventually leading to kidney failure. There is no cure for PKD.

It's believed the accumulation of fluid in the cysts is related to chloride secretion, which is affected by the CFTR (cystic fibrosis transmembrane conductance regulator) gene, according to background information in a news release about the research.

"The CFTR inhibitors could be the basis of a lifelong treatment to slow renal cyst growth and decline in renal function, prolonging dialysis-free patient survival," researcher Dr. Alan S. Verkman said in a prepared statement.

In laboratory tests, he identified a few CFTR inhibitors that reduced the number and growth of cysts by more than 80 percent. He then tested these inhibitors in mice genetically engineered to develop a condition similar to PKD.

Mice treated with these CFTR inhibitors for up to seven days had significantly slower cyst expansion and kidney enlargement, and better preservation of kidney function. There was no evidence that the CFTR inhibitors harmed kidney function.

The findings indicate that CFTR plays a role in the growth of kidney cysts and suggest that CFTR inhibitors may prove useful in treating PKD. However, much more research needs to be done, Verkman said.

"The mouse model of PKD is not the real human disease for many reasons, such as the more rapid progression of disease in mice. Clinical trials will be needed to determine the efficacy of these compounds in human PKD," he said.

The research was expected to be published in the July issue of the Journal of the American Society of Nephrology.

SOURCE: American Society of Nephrology, news release, April 2, 2008