Long-Term Survival and Maturation of Transplanted Cerebral Organoids Derived from Human Induced Pluripotent Stem Cells

Human cerebral organoids have emerged as a promising new therapeutic strategy for cell transplantation after brain injury. Researchers have explored the short-term survival and maturation of human cerebral organoids derived from human embryonic stem cells (hESCs) in animal models. However, the long-term survival and maturation of cerebral organoids derived from human induced pluripotent stem cells (hiPSCs) have not been studied in depth. In this study, we generated cerebral organoids from hiPSCs in a feeder-free culture system. Then, the cerebral organoids were digested into small clusters and transplanted into the frontal cerebral cortex of postnatal day 0 (P0) SCID mice. The long-term survival and maturation of the grafted cerebral organoids were evaluated at 12 months post-transplantation. Our results indicate that grafted cerebral organoids survive well and maintain their forebrain identity in vivo over a long period. The transplanted cerebral organoids showed reduced proliferative capacity, indicating a low risk of tumor formation. The majority of transplanted cells differentiated into cortical neuronal subtypes in different cortical layers in anatomical lamination at 12 months post-transplantation. In addition, a small population of grafted cerebral organoids matured into GABAergic neurons and gliocytes, including astrocytes, microglia and oligodendrocytes. Furthermore, the grafts formed synapses with the host cells and achieved vascularization in the host brain. Our study demonstrates the long-term survival and maturation of cerebral organoids derived from hiPSCs in vivo and provides evidence for the feasibility of cerebral organoids derived from hiPSCs as a potential cell transplantation therapy.