Survival and functional integration of human embryonic stem cell-derived retinal organoids after shipping and transplantation into retinal degeneration rats.

Because derivation of retinal organoids (ROs) and transplantation are frequently split between geographically distant locations, we have developed a special shipping device and protocol capable of the organoids' delivery to any location. Human embryonic stem cell (hESC) derived ROs were differentiated from the hESC line H1 (WA01), shipped overnight to another location, and then transplanted into the subretinal space of blind immunodeficient retinal degenerate (RD) rats. Development of transplants was monitored by spectral-domain optical coherence tomography. Visual function was accessed by optokinetic tests and superior colliculus (SC) electrophysiology. Cryostat sections through transplants were stained with hematoxylin & eosin; or processed for immunohistochemistry to label human donor cells, retinal cell types and synaptic markers. After transplantation, ROs integrated into the host RD retina, formed functional photoreceptors, and improved vision in the rats with advanced RD. The survival and vision improvement are comparable with our previous results of hESC-ROs without a long-distance delivery. Furthermore, for the first time in the stem cell transplantation field, we demonstrated that the response heatmap on the SC showed a similar shape to the location of the transplant in the host retina, which suggested the point-to-point projection of the transplant from the retina to SC. In conclusion, our results showed that using our special device and protocol, the hESC derived ROs can be shipped over long distance and are capable of survival and visual improvement after transplantation into the RD rats. Our data provide a proof-of concept for stem cell replacement as a therapy for RD patients.