Exploring the Potential Use of Amniotic Epithelial Cells for the Treatment of Degenerative Diseases of the Retina

Introduction: Age-related macular degeneration (AMD) is a disease that leads to the progressive loss of the retinal pigment epithelium (RPE). Currently, retinal degeneration is an irreversible process, and no definitive cure is available. Autologous RPE transplantation below the macula provided concrete experimental evidence that replacing these cells may represent a valid therapeutic approach for AMD. In order to obtain a reliable and plentiful source of RPE, in this study, we evaluated the potential of human amniotic epithelial cells (hAEC) from term placenta, to differentiate into RPE in vitro. Methods: Amniotic membranes (AM) from term placentae were either sectioned for the collection of AM fragments, or digested for the release of isolated hAEC. Both AM fragments and cultured hAEC were subjected to a RPE differentiation protocol for up to 40 days, and samples were collected at different time points for the analysis of gene expression by qRT-PCR and protein expression by immunofluorescence staining. Results: Undifferentiated hAEC already expressed some marker genes typical of RPE. However, the differentiation protocol induced an increased expression of these and other markers both at the gene and protein level. Most interestingly, immunofluorescence analysis revealed that, at the end of the differentiation protocol, hAEC expressed some RPE transcription factors at nuclear level, and some tight junction proteins normally expressed by RPE at the membrane level, suggesting a functional localization of these markers. Conclusions: The preliminary results of this study suggest that hAEC have the potential to differentiate towards RPE in vitro. Further studies are needed for the optimization of differentiation protocol and the assessment of function in in vivo models of AMD.