Transplantation of GMP-grade human iPSC-derived retinal pigment epithelial cells in rodent model: the first pre-clinical study for safety and efficacy in China

Abstract

Background: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly due in large part to age-dependent atrophy of retinal pigment epithelium (RPE) cells. RPE cells form a monolayer located between the choroid and the outer segments of photoreceptors, playing multifarious roles in maintenance of visual function. Allogeneically induced pluripotent stem cell-derived RPE (iPSC-RPE or iRPE) has become a potential approach for providing an abundant source of donors for clinical cell products.Transplantation of iRPE has been proven effective in rescuing impaired retinas in Royal College of Surgeons (RCS) rats after approximately 5 to 6 weeks. Here, we explore the long-term (19 weeks) safety and efficacy of human iRPE cell transplantation in pre-clinical animal models. Methods:The expression of human RPE-specific markers in iRPE cells was determined using immunofluorescence staining. For the proliferative test, Ki-67 expression was also verified by immunofluorescence and flow cytometric analysis. Then, iRPE cells were transplanted into the subretinal space of immune-deficient NOD/SCID/IL-2Rgc null (NSG) mice to assess their safety. To evaluate whether the transplanted cells could survive and rescue visual function, we performed color fundus photography, focal electroretinogram and immunostaining after delivering iRPE cells into the subretinal space of RCS rats.Results: Human iRPE cells expressed native RPE-specific markers, such as microphthalmia-associated transcription factor (MiTF), retinal pigment epithelium-specific 65-kDa protein (RPE65) and tight-junction associated structural protein (ZO-1), and their proliferative capacity (Ki-67 expression) was poor after 25 days of induction. A tumorigenicity test revealed no tumor formation or abnormal proliferation in the immunodeficient mice after subretinal injection of 5×10 5 iRPE cells. The transplanted iRPE cells survived for at least 19 weeks and maintained visual function for 15 weeks. Conclusions:In the present study, we provided further evidence for the use of human iRPE transplantation to treat retinal degenerative disease in pre-clinical animal models. Therefore, we consider human iRPE cells a promising source of cell replacement therapy for AMD.

Global spectrum of USH2A mutation in inherited retinal dystrophies: Prompt message for development of base editing therapy

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Advances in cell therapies using stem cells/progenitors as a novel approach for neurovascular repair of the diabetic retina

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Application of the Pluripotent Stem Cells and Genomics in Cardiovascular Research—What We Have Learnt and Not Learnt until Now

“…While significant strides have been made in hPSC differentiation, there remain challenges in the differentiation processes of hESCs and iPSCs, ultimately limiting the widespread use of stem cell technology in research programs and cell replacement therapies. The current state-of-the-art method to induce lineage differentiation from hPSCs involves controlling the differentiation process via the stepwise sequential addition of growth factors and cytokines (Table 1), which are known to play a role during certain steps of differentiation and ultimately induce the phenotypic characteristics ( [41][42][43] Although this has enabled the generation of various cell types, including cells with features of neural subpopulations (cholinergic and dopaminergic neurons), cardiac muscle cells, and hepatocytes, these cells resemble fetal tissue more than adult tissue, in most cases [16]. The use of incomplete differentiated progeny from PSC may hold risks associated with tumorigenicity and excessive proliferation.…”