Nobel laureate Yamanaka warns of rogue "stemcell therapies"

By Tan Ee Lyn

HONG KONG, Oct 9 (Reuters) - Nobel laureate Shinya Yamanakawarned patients on Tuesday about unproven "stem cell therapies"offered at clinics and hospitals in a growing number ofcountries, saying they were highly risky.

The Internet is full of advertisements touting stem cellcures for just about any disease -- from diabetes, multiplesclerosis, arthritis, eye problems, Alzheimer's and Parkinson'sto spinal cord injuries -- in countries such as China, Mexico,India, Turkey and Russia.

Yamanaka, who shared the Nobel Prize for Medicine on Mondaywith John Gurdon of the Gurdon Institute in Cambridge, Britain,called for caution.

"This type of practice is an enormous problem, it is athreat. Many so-called stem cell therapies are being conductedwithout any data using animals, preclinical safety checks," saidYamanaka of Kyoto University in Japan.

"Patients should understand that if there are no preclinicaldata in the efficiency and safety of the procedure that he orshe is undergoing ... it could be very dangerous," he toldReuters in a telephone interview.

Yamanaka and Gurdon shared the Nobel Prize for the discoverythat adult cells can be transformed back into embryo-like stemcells that may one day regrow tissue in damaged brains, heartsor other organs.

"I hope patients and lay people can understand there are twokinds of stem cell therapies. One is what we are trying toestablish. It is solely based on scientific data. We have beenconducting preclinical work, experiments with animals, like ratsand monkeys," Yamanaka said.

"Only when we confirm the safety and effectiveness of stemcell therapies with animals will we initiate clinical trialsusing a small number of patients."

Yamanaka, who calls the master stem cells he created"induced pluripotent stem cells" (iPS), hopes to see the firstclinical trials soon.

"There is much promising research going on," he said.(Editing by Nick Macfie)

((el.tan@thomsonreuters.com)(+852-28436934)(Reuters Messaging:el.tan.thomsonreuters.com@thomsonreuters.net))