Research Article Chitosan Feasibility to Retain Retinal Stem Cell Phenotype and Slow Proliferation for Retinal Transplantation Girish K. Srivastava, 1,2 David Rodriguez-Crespo, 1 Amar K. Singh, 1 Clara Casado-Coterillo, 3 Ivan Fernandez-Bueno, 1,2 Maria T. Garcia-Gutierrez, 1 Joaquin Coronas, 4 and J. Carlos Pastor 1,2 1 Instituto Universitario de Ofalmobiolog´ ıa Aplicada (IOBA), Universidad de Valladolid, Campus Miguel Delibes Paseo de Belen 17, 47011 Valladolid, Spain 2 Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y Le´ on, 47011 Valladolid, Spain 3 Department of Chemical and Biomolecular Engineering, University of Cantabria, 39005 Santander, Spain 4 Instituto de Nanociencia de Aragon (INA), Universidad de Zaragoza, 50018 Zaragoza, Spain Correspondence should be addressed to Girish K. Srivastava; girish@ioba.med.uva.es Received 2 April 2013; Revised 17 December 2013; Accepted 19 December 2013; Published 2 February 2014 Academic Editor: Ulrich Kneser Copyright © 2014 Girish K. Srivastava et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Retinal stem cells (RSCs) are promising in cell replacement strategies for retinal diseases. RSCs can migrate, diferentiate, and integrate into retina. However, RSCs transplantation needs an adequate support; chitosan membrane (ChM) could be one, which can carry RSCs with high feasibility to support their integration into retina. RSCs were isolated, evaluated for phenotype, and subsequently grown on sterilized ChM and polystyrene surface for 8 hours, 1, 4, and 11 days for analysing cell adhesion, proliferation, viability, and phenotype. Isolated RSCs expressed GFAP, PKC, isolectin, recoverin, RPE65, PAX-6, cytokeratin 8/18, and nestin proteins. Tey adhered (28 ± 16%, 8 hours) and proliferated (40 ± 20 cells/feld, day 1 and 244 ± 100 cells/feld, day 4) signifcantly low ( < 0.05) on ChM. However, they maintained similar viability (>95%) and phenotype (cytokeratin 8/18, PAX6, and nestin proteins expression, day 11) on both surfaces (ChM and polystyrene). RSCs did not express alpha-SMA protein on both surfaces. RSCs express proteins belonging to epithelial, glial, and neural cells, confrming that they need further stimulus to reach a fnal destination of diferentiation that could be provided in in vivo condition. ChM does not alternate RSCs behaviour and therefore can be used as a cell carrier so that slow proliferating RSCs can migrate and integrate into retina. 1. Introduction Retina is exposed over life to degenerative conditions. Tis leads into retinal dystrophies, followed by retinal diseases, and ultimately produces visual impairment [1]. Despite grow- ing advances in retinal disease treatments, retinal diseases such as dry AMD, retinitis pigmentosa, and many others are still noncurable or need further improvements in treatment strategies. One of the main events of these diseases is loss of the retinal cells layers (RPE, photoreceptors, etc.) and their proper functions. Tese layers are crucial for maintaining retina anatomy and its functions in eye [2, 3]. From past few years, identifcation and characterization of stem cells of diferent origin have opened new avenues in cell replacement therapy [4, 5]. Retinal stem cells (RSCs) are present during embryonic development; they persist in quiescent forms in the adult mammalian eye in ciliary marginal zone [6–8]. Numerous reports showed that RSCs are promising for developing cell based treatments for retinal diseases [9, 10]. Tey have ability to diferentiate into diferent retinal cell types such as RPE photoreceptors in appropriate diferentiation conditions [6, 9]. Tus, RSCs could serve for replacing the damaged retinal layers in patients. Cell transplantation, cell integration in tissue, and its proper function are still open issues of research. Diferent types of stem cells such as RSCs, neural stem cells (NSCs), bone marrow derived stem cells (BMSCs), and embryonic stem cells (ESCs) have achieved partial success in retinal Hindawi Publishing Corporation BioMed Research International Volume 2014, Article ID 287896, 10 pages http://dx.doi.org/10.1155/2014/287896