Preclinical safety studies of human embryonic stem cell‐derived retinal pigment epithelial cells for the treatment of age‐related macular degeneration

As pluripotent stem cell (PSC)‐based reparative cell therapies are reaching the bedside, there is a growing need for the standardization of studies concerning safety of the derived products. Clinical trials using these promising strategies are in development, and treatment for age‐related macular degeneration is one of the first that has reached patients. We have previously established a xeno‐free and defined differentiation protocol to generate functional human embryonic stem cells (hESCs)‐derived retinal pigment epithelial (RPE) cells. In this study, we perform preclinical safety studies including karyotype and whole‐genome sequencing (WGS) to assess genome stability, single‐cell RNA sequencing to ensure cell purity, and biodistribution and tumorigenicity analysis to rule out potential migratory or tumorigenic properties of these cells. WGS analysis illustrates that existing germline variants load is higher than the introduced variants acquired through in vitro culture or differentiation, and enforces the importance to examine the genome integrity at a deeper level than just karyotype. Altogether, we provide a strategy for preclinical evaluation of PSC‐based therapies and the data support safety of the hESC‐RPE cells generated through our in vitro differentiation methodology.