New version of `rapamycin` can combat kidney disease: Study

Washington: A chemically synthesised version of the drug `rapamycin`, earlier used as an immunosuppressive agent, could be highly effective in treating kidney diseases, scientists have claimed.

Scientists at UC Santa Barbara along with a biotech firm based in Indiana found a signalling protein called mTOR was found to drive cyst growth in polycystic kidney disease. Rapamycin inhibited the growth of cysts, the study found.

The drug `rapamycin` was chemically synthesised into a new version called folate-conjugated rapamycin (FC-rapa) which they found to be highly effective in preventing kidney cyst growth in mice with PKD.

Researchers suggest that FC-rapa could also be effective in human PKD patients without causing the significant unwanted side effects of regular `rapamycin`.

"FC-rapa is a fascinating drug because it combines an extremely specific drug with a delivery approach that targets it to a specific organ, the kidney," study-leader and associate professor in the Department of Molecular, Cellular, and Developmental Biology, Thomas Weimbs said.

The findings based on research performed in 2006, shows that the drug rapamycin, which has been in use for years as an immunosuppressive agent, was highly effective in stopping disease progression in mouse models of polycystic kidney disease.

Over 600,000 people in the US, and 12 million worldwide, are affected by the inherited kidney disease known as autosomal-dominant polycystic kidney disease (ADPKD or PKD).

The disease is characterised by the proliferation of thousands of cysts that eventually debilitate the kidneys, causing kidney failure in half of all patients by the time they reach age 50.

PKD is one of the leading causes of renal failure in the US.

The study is published in this week`s Journal of the American Society of Nephrology.