April 30 : A new study has found that a centuries old Chinese traditional medicine, Triptolide has the potential to stop cyst formation in polycystic kidney disease

Triptolide is derived from a Chinese medicinal herb named Lei Gong Teng, which has been used in traditional medicine to treat cancer, inflammation, and auto-immune diseases and, more recently, also has been tested in Phase I clinical trials as an anti-tumour agent.

The research holds out hope for what would be the first treatment for the disease other than kidney transplant or frequent dialysis.

The study was conducted by a team of researchers led by researcher Dr. Craig Crews at Yale University.

During normal kidney development, cells lining the kidney tubules continue growing and dividing until they receive a signal that the tubule is fully formed. The switch that turns on that signal consists of the growth regulatory proteins PKD1 and PKD2, located on hair-like cilia in the lining of the developing tubules. When urine begins flowing through the tubules, the flow bends the cilia that set off the signal that no more growth is needed.

In people who have a mutation in one of these growth regulatory proteins, however, the message to stop growing never gets delivered, even when urine is flowing and the cilia are bending. So, never sensing a signal to stop, the cells lining the fully-formed kidney tubules keep right on subdividing and growing. The result of this hyperproliferative, unregulated growth: uncontrolled growth of cells lining the tubules and the formation of large cysts in the kidneys.

As part of the study, researchers used triptolide with a less toxic concentration than that used in cancer chemotherapy trials on mice which were bred to have a disease like human polycystic kidney disease.

Researchers found that at that level, the compound marked reduced cyst formation in the mice compared to genetically similar mice not taking the compound.

Vast majority of patients with polycystic kidney disease have a gene causing PKD1 to be missing or to function poorly. Because most patients inherit only one abnormal gene and one functional gene, the body is usually able to compensate for the faulty gene and the person retains kidney function during the 20s and 30s. But through random mutagenesis, the remaining good copy of PKD1 is lost in some cells, which then switch to the hyperproliferative state. As the person’s kidney begins to develop these cysts, the kidney begins to swell, and the person moves to either dialysis or transplant in order to survive.

According to Crews, a treatment that slows down the development of cysts does not have to stop their production completely to be effective.

“If we were able to slow the rate of cyst formation by even 10 percent a year, compounded annually, patients would not die from this disease. A relatively small effect would have an enormous clinical benefit,” Crews said.

The findings of the study were presented as part of the scientific program of the American Society for Biochemistry and Molecular Biology. (ANI)