Preliminary Report of Transplantation of Human Fetal Retinal Pigment Epithelial Cells on Age-related Macular Degeneration Patients. Homo sapiens

Background: Different sources of retinal pigment epithelial cells (RPE) were transplanted to treat Age-related Macular Degeneration. But the mechanisms of therapeutic effect are unclear till now, and GMP level fetal RPE (fRPE) need further evaluation for treatment. Methods: Modified GMP fRPE primary culture system was founded. These RPE were tested on Mer-/- mice and sodium iodate induced retinopathy primate model for safety and feasibility. Five dry-AMD patients and one Stargardt’s Disease patient were enrolled, and received sub retinal transplantation of hfRPE with three dosage cohorts(1×105，2×105，5×105). ETDRS, optic coherent tomographic imaging (OCT), color fundus (CF), fluorescent angiography (FFA), autofluorescence, microperimetry examination were conducted before surgery, and during follow-up period. The studies are registered with ClinicalTrials.gov, numbers NCT02868424. Findings: GMP level fRPE from modified primary culture system has good proliferative capacity and full functions of RPE in vitro. Human fetal RPE can survive long period in sub-retinal space in mice and monkey models of RPE degeneration, and showed therapeutic effect on Mer-/- mice. During our nine-months follow-up of six clinical cases, no endophthalmitis, no vitreous hemorrhage, no proliferative vitreoretinopathy was observed, and epiretinal memrbrane was the only complication. Among the patients, four of them achieved increase in ETDRS visual acuity (VA), of which the greatest improvement was 18 letters, and one kept steady while the other had 9 letters decreased VA. Color fundus photos and OCT demonstrated the existence of the fRPE cells, and improved retinal sensitivity as well as the changes observed in auto fluorescence also can tell the situation of grafted cells to some extent. Interpretation: GMP level fRPE from modified culture system exhibited satisfactory results on in vitro and preclinical experiments. Preliminary clinical trial proved safety of the fRPE subretinal transplantation, and substantiated it a promising therapy for dry AMD including the converted from exudative AMD. Overall design: Retinal mRNA profiles of human fetal RPE cells cultured in xeno-free medium were conducted from 3 aborted fetus.