Interphotoreceptor matrix based biomaterial: Impact on human retinal progenitor cell attachment and differentiation

While cell transplantation therapies show great promise as treatments for retinal degeneration, the challenge of low cell survival upon transplantation motivates exploration of materials that may serve as cell delivery vehicles and promote survival and differentiation. In this study, we explored the native matrix that surrounds the outer segments of photoreceptors and promotes their homeostasis, interphotoreceptor matrix (IPM), as a substrate for human retinal progenitor cells (hRPCs). Bovine IPM was characterized to determine its structure and biochemical composition, and processed to develop substrates for cells. Cell viability, morphology, proliferation and expression of photoreceptors marker genes were studied on IPM-based substrates in vitro. We explored different preparations of IPM as a scaffold. Lectin staining revealed that a distinct honeycomb structure of native IPM is lost during centrifugation to prepare a more concentrated suspension of matrix. Biochemical analysis of bovine IPM indicated presence of glycosaminoglycans and proteins. IPM mediated hRPC attachment and spreading with no signs of cytotoxicity. Cells proliferated more on native IPM substrates compared to IPM that was centrifuged to create a concentrated suspension. Cells cultured on IPM substrates expressed markers of photoreceptors: rhodopsin, NRL and ROM1. Together this data supports further exploration of IPM as a tool for retinal tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 891-899, 2018.