MODELLING THE DEGENERATE NICHE TO INVESTIGATE EFFICACY OF STEM CELL THERAPIES FOR INTERVERTEBRAL DISC DEGENERATION

Introduction Current strategies to treat back pain address the symptoms but not the underlying cause. Here we are investigating a novel hydrogel material (NPgel) which can promote MSC differentiation to Nucleus pulposus cells. Current in vitro studies have only explored conditions that mimic the native disc microenvironment. Here, we aim to determine the stem cells regenerative capacity under conditions that mimic the degenerate environment seen during disc degeneration. Methods hMSCs were encapsulated in NPgel and cultured for 4 weeks under hypoxia (5%) with ± calcium (2.5mM and 5.0mM CaCl 2 ), IL-1β and TNFα either individually or in combination to mimic the degenerate microenvironment. Cell viability was assessed by Alamar blue assay. Histological and immunohistochemical analysis investigated altered matrix and matrix degrading enzyme expression. Results Viability of hMSCs was maintained under all culture conditions. Matrix deposition of glycosaminoglycans were observed under all conditions, MMP13 expression was upregulated by calcium but not by pro-inflammatory cytokines IL-1β and TNFα. Conclusions We are developing an in vitro modelling system which can be used to test novel therapies within a degenerate microenvironment. Interestingly, our preliminary findings suggest calcium is a major contributor to regulating MMP13 in this model system. Investigating the degenerate niche will identify targets for inhibition to provide the correct niche to promote regeneration of the IVD. No conflict of interest. Funding: BMRC, MERI Sheffield Hallam University, for joint funding the Daphne Jackson Trust fellowship.