Prometheus unbound - Stem cell therapies
Researchers have yet to realise the old dream of regenerating organs, but they are getting closer
Jul 6th 2013 |From the print edition
PROMETHEUS, a Titan bound to a rock by Zeus, endured the daily torture of an eagle feasting on his liver, only to have the organ regrow each night. Compared with this spectacle, a video on the website of Nature this week seems decidedly dull. It shows a collection of pink dots consolidating into a darker central glob. But something titanic is indeed happening. The pink dots are stem cells, and the video shows the development of a liver bud, something which can go on to look and act like a liver. Takanori Takebe and Hideki Taniguchi of Yokohama City University, in Japan, who made the video, have created working human-liver tissue.
Researchers have long dreamed that stem cells might be used to repair or replace damaged tissue, an aspiration known as regenerative medicine. Embryonic stem cells, in particular, are “pluripotent”, meaning they are able to become any other type of cell. And it is now possible to induce pluripotency in cells that have not come from embryos, thus circumventing the ethical minefield previously associated with obtaining them.
Last year Shinya Yamanaka of Kyoto University won a Nobel prize for the invention of induced pluripotency. He had shown how four signal proteins can reprogram adult cells into a pluripotent state. Beside dealing with the ethical problems of embryonic cells, Dr Yamanaka’s induced pluripotent stem (iPS) cells allow—at least in theory—a treatment to be created from a patient’s own body. This would have his own genetic make up and would thus not attract the attention of his immune system. Realising such treatments has been fiendishly difficult. But Dr Takebe’s paper in Nature is one of several signs that the Promethean dream is slowly coming to life.
Clinical trials of pluripotent cells are already happening, though they hark back to the days when only cells derived from embryos were available. An American firm called Advanced Cell Technology (ACT) is using them to treat macular degeneration, a cause of blindness. Last year it reported promising results in two patients and Gary Rabin, the firm’s boss, says tests continue. Even if this specific approach works, though, it is likely to be overtaken by iPS technology. The Japanese, not surprisingly, are in the lead. Soon, the country’s health ministry is expected to approve the first clinical trial of iPS cells, also for macular degeneration. But ACT is not far behind. It hopes to begin a trial of platelets (blood-cell fragments involved in clotting) made from iPS cells. And other firms want to treat everything from Parkinson’s disease to glaucoma to multiple sclerosis.
Read more at: http://www.economist.com/news/science-and-technology/21580440-researchers-have-yet-realise-old-dream-regenerating-organs-they-are?
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