REVERSAL OF FIBRONECTIN-INDUCED HIPPOCAMPAL DEGENERATION WITH ENCAPSULATED MESENCHYMAL STROMAL CELLS.

Mesenchymal stromal cells (MSC) can promote tissue protection following injury, in part by modulating inflammatory cell responses. The aim of this study was to investigate the potential tissue protective properties of encapsulated MSCs (eMSC) in an organotypic injury model induced by fibronectin culture. MSC were encapsulated in alginate beads containing a network of nanopores, which segregate the cells from the extracapsular milieu, while still permitting diffusion into and out of the capsule. An increase in blood brain barrier permeability during pathological conditions permits the influx of blood plasma constituents that can be quite harmful to surrounding tissues. In particular, increased concentrations of fibronectin have been shown in a number of diseases and CNS traumas, co-localizing in areas of activated microglia. We observed over a 14-day period, a consistent increase in OHC degradation in the presence of fibronectin measured by a significant decrease in slice area, the breakdown in OHC pyramidal layers, and consistent cell death over the culture period. Microglial ionized calcium-binding adapter molecule 1 (IBA-1) expression remained elevated throughout the culture period with the majority found within the pyramidal layers. When eMSC were added to the cultures, a significant decrease in OHC degradation was observed as reflected by a reduction in OHC area shrinkage and in the amount of cell death. In the presence of eMSC, pyramidal layer structure was maintained and axonal extension from the periphery of the OHCs was observed. Therefore, MSC, delivered in a nanoporous alginate matrix, can modulate responses to injury by reversing fibronectin-induced OHC degradation.