Abstract
Purpose::
To determine the survival, migration, and differentiation of retinal progenitor cells (RPCs) adherent to non-porous and porous micro-machined poly(methyl methacrylate) (PMMA) scaffolds and transplanted sub-retinally in C57bl/6 mice.
Methods::
GFP-positive murine RPCs were cultured on laminin-coated non-porous and 10µm pore containing ultra-thin (6 µm ) micro-machined PMMA scaffolds for up to seven days. Cell adhesion to and survival on PMMA scaffolds were determined by fluorescent microscopy. Non-porous and porous PMMA scaffolds with adherent RPCs were then transplanted into the sub-retinal space of C57bl/6 mice and sacrificed after 4 weeks. Engrafted eyes were removed and cryosectioned at 12µm for analysis. GFP-positive RPCs were imaged to measure cell survival and migration. Immunohistochemical labeling of the markers neurofilament-200 (nf-200), glial fibrillary acidic protein (GFAP) and recoverin were used to evaluate differentiation of RPCs.
Results::
RPC adherence and survival were similar in culture on both types of scaffolds, although transplantation with non-porous scaffolds showed limited RPC retention. During transplantation, non-porous scaffolds lost the majority of their RPCs. Porous scaffolds demonstrated enhanced RPC attachment during transplantation and allowed for process outgrowth and cell integration into host retinal layers. Integrated cells expressed the mature neuronal marker, nf-200, the glial marker, GFAP, and the photoreceptor marker, recoverin .
Conclusions::
Stem and progenitor cells can be combined with polymer substrates for the generation of tissue equivalents in culture. RPCs delivered using these polymers send projections into the host retina and express at least 1 retina-specific marker. Micromachined, ultra-thin PMMA scaffolds provide a suitable cytoarchitectural environment for tissue engineering and transplantation into the diseased eye.
Keywords: retina • transplantation • regeneration