THE VISION OF more than nine patients with severe sight loss has been restored following the transplant of human embryonic stem cells (hESCs).
New research published in The Lancet, finds that hESC transplants used to treat severe vision loss in 18 patients with different forms of macular degeneration appeared safe up to 3 years post-transplant, and the technology restored vision in more than half of the patients.
Sight degeneration
The cells were differentiated into retinal pigment epithelium cells and transplanted into nine patients with two different sight degeneration - Stargardt’s macular dystrophy and nine patients with dry atrophic age-related macular degeneration.
No effective treatments exist for either condition and eventually the light-receiving cells of the retina degenerate leading to complete blindness.
All participants were injected with one of three different doses of retinal cells – 50 000, 100 000, and 150 000 cells – under the retina of the eye with the worse vision.
The cells were found to be well tolerated for up to 37 months after transplantation. No safety concerns were detected up to 22 months after the transplant.
Follow-up testing
Follow-up testing showed that 10 out of 18 treated eyes had substantial improvements in how well they could see, with 8 patients reading over 15 additional letters in the first year after transplant.
Visual acuity remained the same or improved in seven patients, but decreased by more than 10 letters in one patient. Importantly, untreated eyes did not show similar visual improvements.
This is the first long-term safety report of this sort of transplant, which researchers say could have the potential to be used for other parts of the body.
Lead author Professor Robert Lanza, Chief Scientific officer at Advanced Cell Technology in theUSA said the eye have become the first parts of the human body to benefit from this technology.
Co-lead author Professor Steven Schwartz from the Jules Stein Eye Institute, Los Angeles, said:
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.
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