Human Embryonic Stem Cell–Derived Cells Rescue Visual Function in Dystrophic RCS Rats

Embryonic stem cells promise to provide a well-characterized and reproducible source of re-placement tissue for human clinical studies. An early potential application of this technology is the use of retinal pigment epithelium (RPE) for the treatment of retinal degenerative dis-eases such as macular degeneration. Here we show the reproducible generation of RPE (67 passageable cultures established from 18 different hES cell lines); batches of RPE derived from NIH-approved hES cells (H9) were tested and shown capable of extensive photorecep-tor rescue in an animal model of retinal disease, the Royal College of Surgeons (RCS) rat, in which photoreceptor loss is caused by a defect in the adjacent retinal pigment epithelium. Improvement in visual performance was 100 % over untreated controls (spatial acuity was ap-proximately 70 % that of normal nondystrophic rats) without evidence of untoward pathol-ogy. The use of somatic cell nuclear transfer (SCNT) and/or the creation of banks of reduced complexity human leucocyte antigen (HLA) hES-RPE lines could minimize or eliminate the need for immunosuppressive drugs and/or immunomodulatory protocols