Skeletal Regeneration: Stem Cell Therapy

Abstract

Bone marrow stromal cells (BMSCs) contains a subset of skeletal stem cells (SSCs) that are multipotent, capable of forming cartilage, bone, hematopoiesis-supportive stroma and marrow adipocytes. SSCs have been identified as pericytes, cells on the abluminal side of marrow sinusoids, and have demonstrated the ability to self-renew. Based on their ability to recapitulate a bone/marrow organ upon in vivo transplantation, they are being investigated extensively for use in bone tissue engineering. In using BMSCs/SSCs, a number of issues needed to be considered such as the embryological origin, the bone site from which they are taken, how they are expanded ex vivo prior to transplantation, and the type of scaffold that can be used to retain not only their ability to make bone, but also to maintain the SSC subset within the population. Processes are now being developed for the generation of clinical grade BMSCs/SSCs that maintain their essential biological properties. However, there are a number of hurdles that need to be addressed such as the generation of weight-bearing but resorbable scaffolds, induction of rapid vascularization, and the parameters by which efficacy can be assessed before stem cell-based bone regeneration will become an every-day reality.