In Vitro Differentiation of Human Bone Marrow Stem Cells into Retinal Pigment Epithelium

Abstract

Introduction: Dysfunction, degeneration, and loss of retinal pigment epithelial (RPE) cells are prominent features of subtypes of retinitis pigmentosa (RP) which is a cause of visual disability. In this condition, there is progressive visual loss that often leads to blindness. A variety of therapeutic approaches to delay the degenerative process are under development, the most promising of which is the stem cell regenerative therapy. Stem cells are self-renewing cells capable of transdifferentiation into a number of cell lineages. Mesenchymal stem cells (MSCs) represent a type of stem cell with remarkable proliferative, regenerative and transdifferentiation ability. Aim of the Work: The aim of this work was to evaluate the ability of bone marrow derived MSCs to differentiate into retinal pigmented epithelial cells in vitro as a step towards regeneration of degenerated retinal cells as in cases of retinitis pigmentosa. Patients and Methods: The present study was carried out on 20 bone marrow samples obtained from donors undergoing bone marrow aspirations, at EL-Maadi Military Hospital. 3 ml bone marrow were aspirated, mesenchymal stem cells were separated and induced to RPE lineage through culture in the presence of nicotinamide NIC and factors from the TGF-b superfamily (Activin A). The BMSC- derived pigmented-like cells were evaluated for the morphology, function, and marker expression of authentic RPE using RT-PCR for RPE65 mRNA. Results: Bone marrow derived mesenchymal stem cells in all samples demonstrated the morphologic characteristics as well as molecular markers of RPE cells after 8 weeks of culture with activin A and nicotinamide. Conclusion: In the present study, compelling evidences support the possibility of differentiation of bone marrow stem cells into retinal pigmented epithelial cells (RPE) which have the morphology, function, and marker expression of authentic RPE.