P8. Electrospun synthetic bone grafts promote mesenchymal stem cell function and spinal fusion

Abstract

BACKGROUND CONTEXT Synthetic bone grafts are being developed to lessen the need for autograft and allograft. Electrospun bone grafts (ESBG) have a highly porous nanofibrous structure with a large surface area-to-volume ratio, potentially improving its osteoconductive and osteoinductive properties. PURPOSE We investigate the potential of ESBG to stimulate mesenchymal stem cell (MSC) function in vitro, and to facilitate BMP-2 mediated spinal fusion in a rat model. STUDY DESIGN/SETTING In vitro analysis of MSC adhesion, proliferation, and differentiation seeded in ESBG. In vitro analysis of ESBG-facilitated posterolateral spine fusion in a rat model. PATIENT SAMPLE For the in vitro study: MSCs seeded with and without ESBG. For the in vivo study: 36 Lewis rats underwent posterolateral spine fusions. OUTCOME MEASURES In vitro: adhesion, proliferation, and osteogenic differentiation of MSCs. In vivo: rat fusion rate, fusion stiffness, fusion bone volume, fusion connectivity density and histological evaluation. METHODS Adhesion, proliferation, and osteogenic differentiation of MSCs seeded with and without ESBG for 7 days was analyzed. In vivo, 36 rats underwent posterolateral spine fusions in the following groups: (I) ESBG+bone marrow aspirate (BMA), (II) ESBG+BMA+BMP-2 (low-dose), and (III) BMA. Rats were followed for 3 months and the fusion masses were characterized with manual palpation, biomechanical tests, micro-CT and histological evaluation. RESULTS Ninety percent of cultured MSCs adhered to ESBG. When seeded in ESBG, there was a significant increase in MSC proliferation (0.18 to 0.43, p CONCLUSIONS This is the first reported characterization of ESBG for spinal applications. ESBGs provide a novel scaffold that supports MSC binding, proliferation and osteogenic differentiation. In a rat spine fusion model, ESBG impregnated with BMA and low-dose BMP-2 allowed for 100% fusion with strong biomechanical properties. ESBGs represent a promising synthetic graft and should be further investigated for clinical feasibility. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.