Human RPE Cells Transplanted into Monkey Eyes

Article: Scientists Take Important Step Toward Using Retinal Cell Transplants to Treat Blindness
Source: Icahn School of Medicine at Mount Sinai, via Fierce Biotech 
Published: January 14, 2021
Article: Retinal Cell Transplant Clears Experimental Hurdle Toward Treating Blindness
Source: International Society for Stem Cell Research
Published: February 9, 2021

Transplantation of hRPESC-RPE grafts in monkey eyes

The possibility of using stem cells to restore vision in degenerative retinal diseases is being explored by an international team of researchers from Singapore, the United States, and Germany. The retinal pigment epithelium (RPE) is the outermost layer of the retina and serves an important function as both a barrier between the retina and the choroid (blood-retina barrier) and in recycling photoreceptor discs, a necessary process at the cellular level for vision to take place. Malfunctioning of the RPE leads to diseases such as macular degeneration. Transplants in the past using the patient's own RPE have had limited success, notably uncertain cell survival delivered by suspension and the risk of uncontrolled cell proliferation. The present study explores the potential of using RPE transplants from donor sources to investigate compatibility matching, as well as the safety and feasibility of this option. The particular type of cell they used, human RPE stem cell-derived RPE (hRPESC-RPE), is itself an interesting approach. But for simplicity, the researchers extracted human RPE stem cells from donated cadaver adult eyes and transplanted them into a non-human primate model (nine cynomolgus monkeys). They found that the stem cell patches remained stable and integrated in vivo for at least three months without serious side effects, and that these stem cell-derived RPE at least partially took over the function of the original RPE to support the endogenous photoreceptors. The complexity of restoring functional vision extends far beyond safe cell survivability, but what is attractive about this method is that it, if successful in clinical trials, would open the possibility of an unlimited source of retinal donor tissue for transplant.

My rating of this study: ⭐⭐⭐

Liu Z, Parikh BH, Tan QSW, et al. "Surgical Transplantation of Human RPE Stem Cell-Derived RPE Monolayers into Non-Human Primates with Immunosuppression." Stem Cell Reports. 14 January 2021. https://doi.org/10.1016/j.stemcr.2020.12.007