Repair of Full Thickness Osteochondral Defects in a Rabbit Model Using Mesenchymal Stem Cell-seeded Poly(l)-lactic Acid Nanofibrous Scaffolds

INTRODUCTION: Over sixty million Americans currently suffer from diagnosed osteoarthritis (OA). Because articular cartilage has a limited capacity for self-renewal, the ultimate remedy for many patients with OA is a total joint replacement. As the population lives longer, more active lives, many patients will outlive their prostheses. Tissue engineering offers the promise of tissue regeneration in the repair of degenerative diseases such as OA. In vitro studies have shown bone marrow derived mesenchymal stem cells (BMD MSCs) are able to differentiate into many cell types including cartilage depending on culture conditions and growth factors. Three-dimensional scaffolds have been used to aid in the differentiation of stem cells as well. Among synthetic polymers, poly-a-hydroxy esters are most commonly used in tissue engineering. Both in vivo and in vitro studies have shown these polymers maintain chondrocyte phenotype and stimulate ECM production. With respect to articular cartilage repair, the structure of these scaffolds can be important in the development, maturation and survival of stem cell-derived tissues. Nanofibrous scaffolds with structural properties similar to native collagen fibrils and seeded with chondrocytes have been shown to repair full-thickness defects in a pig model. The effectiveness of nanofibrous scaffolds in promoting MSC repair of articular cartilage remains unknown. This study utilizes the novel combination of a polylactic acid nanofibrous scaffold seeded with (BMD-MSCs) to repair an osteochondral defect in the weight-bearing region of a rabbit femoral condyle.