Regenerative medicine and gene therapy

“Photoreceptors and RPE cells are key candidates for transplantation,” said Dr. James Bainbridge, PhD, FRCOphth, of Moorfields Eye Hospital and UCL Institute of Ophthalmology. Dr. Bainbridge presented several new perspectives on RPE cell transplantation and the recent results of safety trials of these at the 14th EURETINA Congress. 

His work focuses on transplanting RPE derived from human embryonic stem cells (hES-RPE) into the eyes of patients with end-stage Stargardt disease, the most common form of juvenile macular degeneration. “It has already been shown that donor hES-RPE cells survive in the mouse,” said Dr. Bainbridge, “and that these cells protect retinal function in the mouse.” 

Dr. Bainbridge and his team thus set up a clinical trial to assess the safety of the procedure in humans. Twelve subjects received a subretinal injection of between 50,000 and 200,000 cells hES-RPE cells suspended in 0.15 ml. “The rationale wasto promote photoreceptor survival and function by replenishing degenerate RPE  with functioning RPE,” said Dr. Bainbridge. “This process faces many challenges: safety, donor cell survival and ultimate donor cell function,” said Dr. Bainbridge. 

The study’s objectives were to evaluate these three parameters.Current results indicate that the procedure is safe in the short term. The ocular fundus eveloped hyperpigmentation, “which may reflect the survival of the donor RPE cells,” he said.  Although functional improvement has not yet been observed, this was probably not to be expected, considering the advanced stage of the disease of the eyes included in the study.