Source: The Guardian
Patients with a devastating eye disease who had embryonic stem cell therapy to improve their sight have suffered no major side-effects since they had the treatment, scientists report…
There had been concerns that the cells could be rejected by the body’s immune system or become overactive and grow into tumours. But after following the patients for up to three years, researchers said the treatment appeared to be safe.
Nine patients with Stargardt’s macular dystrophy and nine with dry atrophic age-related macular degeneration had injections of 50,000 to 150,000 retinal pigment cells behind the retina of their worst-affected eye. The pigment cells were created in the lab by treating human embryonic stem cells (hESCs) with chemicals that make them transform into retinal cells.
“The vision of most patients improved after transplantation of the cells. Overall, the vision of the patients improved by about three lines on the standard visual acuity chart, whereas the untreated fellow eyes did not show similar improvements in visual acuity. The patients also reported notable improvements in their general and peripheral vision, as well as in near and distance activities,” said Robert Lanza, chief scientific officer of Advanced Cell Technology, which funded the research.
One of the patients, a 75-year-old horse rancher from Kansas, was blind in the eye he had treated. A month after the therapy, his vision had improved by 10 lines and he had taken to riding horses again. Other patients could use their computers or read a watch, Lanza said.
“Little things like that – which we all take for granted – have made a huge difference in the quality of their life. Indeed, one patient recently went to the mall for the first time, and another patient can travel to the airport by herself,” he added.
Writing in The Lancet, the scientists said that patients had tolerated the implanted cells for up to 37 months. They found no evidence of hyper-proliferation or rejection of the cells during a typical follow-up period of 22 months.
“Our results suggest the safety and promise of hESCs to alter progressive vision loss in people with degenerative diseases and mark an exciting step towards using hESC-derived stem cells as a safe source of cells for the treatment of various medical disorders requiring tissue repair or replacement,” said Professor Steven Schwartz, one of the study leaders from the Jules Stein Eye Institute in Los Angeles.
In an accompanying article, Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine in Winston-Salem, US, wrote: “Since the discovery of hESCs in 1998, much has transpired, including political, ethical and scientific debates, with an overall push to achieve the promise of human therapies. Now, we have follow-up that extends to longer than three years in patients treated with hESC-derived stem cells, showing both safety and apparent efficacy.”