Retinitis pigmentosa (RP) is a group of inherited diseases in which progressive photoreceptor dysfunction is associated with cell loss and eventual retinal atrophy. No effective treatment was available for this retinal degeneration by now. Rapid advances in stem cell biology have opened an alternative, fascinating perspective treatment for RP. Stem cells as donor cells used in RP include retinal stem cells from the embryonic eyeball, adult stem cells such as bone marrow-derived mesenchymal stem cell and embryonic stem cells (ESCs) or induced pluripotent stem (iPS) cells. Our investigations suggested that bone marrow mesenchymal stem cells (MSCs) and retinal stem cells can improve the visual function of Royal College of Surgeons (RCS) rats, the RP model. The grafted cells in the subretinal space can survive, migrate and differentiate to photoreceptors, the therapeutic effect of cell transplantation was partly achieved trophic factors secreted from grafted stem cells, which resulted in survival of more photoreceptor cells in RCS rats. We also observed the therapeutic effect of human retinal stem cells isolated from the abortive embryos at 12 weeks on the RP patients when transplanted into retinal space, 8 transplantation cases showed that the vision of patients were improved to some extent. However, the ethical risks of using human embryos force us to look for a new stem cell source for transplantation. By designing a simplified cell-electrofusion chip, we succeeded in quick and accurately electro-fused NIH3T3 and mouse embryonic stem cells, the pluripotent hybrid cells demonstrated some characters of iPS cells. It suggested that cell-electrofusion can reprogram the somatic cells quickly and efficiently. Although stem cell transplantation has been proved to be a promising tool and potential therapies for treating incurable RP, it is too early to be optimistic that stem cells will be used immediately clinically to cure this neurodegenerative diseases. Several issues about safety, effectiveness, ethical and feasibility must be considered before the adoption of stem cell replacement is widely accepted in clinical medicine.
Keywords: Stem cell; transplantation; iPS; Retinitis pigmentosa
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