Stem cells may help blind see

For the first time, scientists have used embryonic stem cells to improve the sight of two almost blind women, a breakthrough which they say raises the hope of a cure for age-related vision loss.

The landmark study, published in The Lancet, involved one elderly patient with dry age-related macular degeneration (AMD) and a younger patient with Stargardt’s disease, the leading cause of macular degeneration in young people.

The transplants appeared safe after four months, and both patients had some improvement in vision. The future goal will be to treat patients earlier in the disease process, in order to boost the prospects of improving or retaining sight in new patients, the researchers said. “It has been over a decade since the discovery of human embryonic stem cells (hESC). This is the first report of hESC-derived cells ever transplanted into patients, and the safety and engraftment data to-date looks very encouraging,” said study co-author Dr Robert Lanza from Advanced Cell Technology.

“Though several new drugs are available for the treatment of the wet type of AMD, no proven treatments currently exist for either dry-AMD or Stargardt’s disease.

“Despite the progressive nature of these conditions, the vision of both patients appears to have improved after transplantation of the cells.

“This is particularly important, since the ultimate goal of this therapy will be to treat patients earlier in the course of the disease where more significant results might potentially be expected.”In the study, each patient had a single eye injected with about 50,000 retinal pigment epithelium (RPE) cells that had been derived from embryonic stem cells.

Both the patients received low-dose immunosuppression therapy that doctors began to taper off after six weeks. After surgery, structural evidence confirmed cells had attached to Bruch’s membrane — the blood-retina barrier that separates the RPE cells of the retina from the choroid — and survived throughout the study period.No safety concerns emerged in the four months and there were no signs of rejection or abnormal cell growth, noted the authors.

They said: “Our study is designed to test the safety and tolerability of hESC-RPE in patients with advanced-stage Stargardt’s macular dystrophy and dry age-related macular degeneration. “So far, the cells seem to have transplanted into both patients without abnormal proliferation, teratoma formation, graft rejection, or other untoward pathological reactions or safety signals.

“The ultimate therapeutic goal will be to treat patients earlier in the disease processes, potentially increasing the likelihood of photoreceptor and central visual rescue.”

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