Stem-cell research pioneered by Shinya Yamanaka, one of two men to receive the 2012 Nobel Prize for Medicine, may pave the way for novel treatments—but Yamanaka warns patients against the lure of the field's promise and untested stem-cell treatments.
Stem-cell technique could be used to treat human diseases
Yamanaka of the Kyoto Institute
and John Gurdon of the United Kingdom's Gurdon Institute received the Nobel Prize earlier this week
for discovering that fully specialized adult cells can be reprogrammed back into stem cells and could be used to repair damaged organs.
Specifically, Yamanaka discovered that he could reprogram intact, mature skin cells in mice to become unspecialized stem cells by adding just four genes to reset them. The technique now is known as induced pluripotent stem cells (iPS).
Although Yamanaka's findings provide researchers with a way to avoid ethical concerns associated with the use of human embryonic stem cells, Reuters notes that safety concerns make it unclear how his techniques will be used to treat human diseases.
Moreover, some health experts remain unconvinced that iPS cells will be as effective as human embryonic stem cells. One recent study suggests iPS cells die more quickly than embryonic cells, while another study indicates they may cause multiple genetic mutations.
In Japan, researchers at the Riken Center for Developmental Biology plan to use the iPS technique to restore vision in a trial on patients with macular degeneration. They will turn skin cells from patients into stem cells before cultivating them into specific retinal cells to be transplanted into the patients' eyes.
"There is a bit of a divergence between Japan and the rest of the world on this," says University of College London's Chris Mason, adding, "Scientists in Japan are trying to move very rapidly towards clinical trials of iPS cells, whereas many of us still feel there are a lot of issues to overcome, especially in terms of safety."
Yamanaka: Beware untested therapies
In countries such as China, India, and Mexico, "stem cell therapies" are being offered as cures for diseases such as multiple sclerosis, diabetes, and Parkinson's disease, Reuters
reports. However, Yamanaka says, "Many so-called stem cell therapies are being conducted without any data using animals, preclinical safety checks."
He calls on stem-cell researchers and physicians to "double check we don't see any severe side effects in patients after transfer… We are getting closer and closer," Yamanaka says. In fact, for disease such as macular degeneration, Yamanaka says the technology is "almost ready to go" (Bennett, Bloomberg, 10/9; Lyn, Reuters, 10/9; Hirschler/Kelland, Reuters, 10/8).
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