Stem Cell Transplant Clears Clinical Safety Hurdle for the Treatment of Wet Age-Related Macular Degeneration

Age-related macular (AMD) degeneration is a leading cause of vision impairment and blindness in the elderly population. In so-called wet AMD, new, abnormal blood vessels grow in the central part of the retina called macula, which is required for high-acuity central vision, leading to fluid and blood leakage and macular damage or dysfunction. Although wet AMD accounts for a minority of AMD cases, 90% of AMD-related cases of blindness are due to wet AMD.

Wet AMD in its early stages can be treated with drugs to reduce the formation of new blood vessels, but this treatment is inefficient in cases where blood vessel formation is already in its advanced stages. A new, alternative treatment for those patients may be surgical removal of the abnormal blood vessels followed by the transplantation of stem cell-derived retinal cells, according to a recent study led by Yong Liu and colleagues from Third Military Medical University Southwest Hospital, China, published in the journal Stem Cell Reports.

In their clinical study, involving 10 patients with wet AMD, the researchers first developed a method for safely removing the newly formed blood vessels followed by the transplantation of stem cell-derived retinal cells to replace the patients’ damaged or lost retinal cells. The retinal structure improved in those patients where blood vessel patches were completely removed during surgery, suggesting that the transplanted cells survived and repaired the damaged retina. Further, visual acuity remained stable or improved in those patients during the 12-months follow-up, with limited side effects. In contrast, patients where the blood vessel patches could only partially be removed experienced persistent bleeding and inflammation in the eye and an incomplete regeneration of the retina, and vision did not improve in those patients. The researchers concluded that complete and safe removal of the blood vessel patches prevents inflammation and generates a milieu favorable for transplant survival and integration. Follow up studies with larger groups of patients are required to confirm the clinical efficacy and favorable safety profile of this type of treatment.

Image Caption: The vitreous cavity was filled with perfluoro decalin to reattach the retina.
Credit: Provided by Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, China, Yong Liu