from the consider-the-source dept.
It's official: The first use of induced pluripotent stem (iPS) cells in a human has proved safe, if not clearly effective. Japanese researchers reported in this week's issue of The New England Journal of Medicine (NEJM) that using the cells to replace eye tissue damaged by age-related macular degeneration (AMD) did not improve a patient's vision, but did halt disease progression. They had described the outcome at conferences, but publication of the details is an encouraging milestone for other groups gearing up to treat diseased or damaged organs with the versatile replacement cells, which are derived from mature tissues.
This initial success "is pretty momentous," says Alan Trounson, a stem cell scientist at the Hudson Institute of Medical Research in Melbourne, Australia. But the broader picture for iPS therapies is mixed, as researchers have retreated from their initial hopes of creating custommade stem cells from each patient's tissue. That strategy might have ensured that recipients' immune systems would accept the new cells. But it proved too slow and expensive, says Shinya Yamanaka of Kyoto University in Japan, who first discovered how to create iPS cells and is a co-author of the NEJM paper. He and others are now developing banks of premade donor cells. "Using stocks of cells, we can proceed much more quickly and cost effectively," he says.
[...] Immediately after surgery the first patient reported her eyesight was brighter. [Masayo] Takahashi says the surgery halted further deterioration of her eye, even without the drug injections still being used to treat her other eye, and there were no signs of rejection of the graft as of last December.
In related news, another article published on the same day in the same journal describes three elderly women who were blinded by an unproven stem cell treatment. They were treated at a for-profit clinic in Florida for the same condition as those in the Japanese study: age-related macular degeneration. In their case, stem cells derived from fat tissue were used. Visual acuity in the three patients ranged from 20/30 to 20/200 before the treatment, and 20/200 to "no light perception" a year later.
Autologous Induced Stem-Cell–Derived Retinal Cells for Macular Degeneration (DOI: 10.1056/NEJMoa1608368) (DX)
Vision Loss after Intravitreal Injection of Autologous "Stem Cells" for AMD (DOI: 10.1056/NEJMoa1609583) (DX)
Editorial discussing the previous papers:
Doctors have taken a major step towards curing the most common form of blindness in the UK - age-related macular degeneration.
Douglas Waters, 86, could not see out of his right eye, but "I can now read the newspaper" with it, he says. He was one of two patients given pioneering stem cell therapy at Moorfields Eye Hospital in London.
[...] Doctors have devised a way of building a new retinal pigment epithelium and surgically implanting it into the eye. The technique, published in Nature Biotechnology [DOI: 10.1038/nbt.4114] [DX], starts with embryonic stem cells. These are a special type of cell that can become any other in the human body. They are converted into the type of cell that makes up the retinal pigment epithelium and embedded into a scaffold to hold them in place. The living patch is only one layer of cells thick - about 40 microns - and 6mm long and 4mm wide. It is then placed underneath the rods and cones in the back of the eye. The operation takes up to two hours.