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Brandon M. Menke, Vijaya B. Joshi, Amaraporn Wongrakpanich, Kristin R. Anfinson, Megan R. Streb, Mari E. Eyestone, Aliasger K. Salem, Budd A. Tucker; Enhanced Progenitor Cell Integration and Differentiation Following Transplantation on to PLGA Polymer Construct. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5899.
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© ARVO (1962-2015); The Authors (2016-present)
Retinal degenerative diseases are the leading cause of incurable blindness in the United States. For diseases such as Retinitis Pigmentosa and Age-Related Macular Degeneration, where cell atrophy is the predominate pathophysiology of disease, stem cell based replacement strategies represent a promising therapeutic approach. However, as promising as stem cell transplantation may be, problems related to cellular survival, migration and functional tissue-specific integration remain. Several studies, including our own, have shown that following bulk cell injection, less than 0.01% of transplanted cells survive and even fewer actually integrate within the host retina. In large part, this can be accounted for by the lack of donor cell support following bolus cell injection. Thus, the purpose of this study was to develop a biomimetic polymer support scaffold sufficient to increase cellular survival and integration, as well as independently induce retinal specific differentiation following delivery of induced pluripotent stem cell derived retinal progenitor cells (iPS-RPCs) to dystrophic retinas.
Retinal explantation of wild type iPS-RPCs were performed using retinas isolated from Rho-/- (retinal degeneration) mice. Poly(D,L-lactide-co-glycolide) (PLGA) scaffold was prepared using standard solvent-casting and particle-leaching method. Briefly, 200 mg of PLGA 50:50 was dissolved in 3 ml of dichloromethane (DCM). 2 g of sodium chloride (NaCl) was added into the DCM solution and the suspension was cast into a glass mold. After air drying the mold for 2 to 3 hours, the resulting composite was immersed in excess of distilled water to leach out NaCl. The leaching process was carried out for 48 hours at room temperature with constant stirring. Samples were then freeze dried and stored in a desiccator until used. Immuno-SEM, TEM, Western blotting, RT-PCR and immunocytochemistry were used to assess the level of expression and localization of retinal specific markers from iPS-RPCs. SEM was used for polymer characterization.
We report the microfabrication of a biodegradable, PLGA polymer scaffold with superior mechanical properties for the delivery of iPS-RPCs. Evaluation of the polymer through SEM showed desirable porosity, cell adhesion, and structural properties. Furthermore, immunohistochemical analysis revealed that these polymer scaffolds independently promoted the differentiation of iPS-RPCs into mature retinal cell types.
PLGA polymer based scaffolds exhibit novel characteristics that make it a suitable vehicle for iPS-RPC delivery to dystrophic retinas, as well as producing a matrix for which disease modeling may occur.
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