Mesenchymal stem cells for bone repair: Preclinical studies and potential orthopedic applications

Mesenchymal stem cell-based bone regeneration has been demonstrated in various animal models. Preclinical models described in this review primarily focused on the repair of segmental defects. Other orthopedic applications, such as spine fusion and craniotomy defects, are also of interest for the delivery of MSCs. Although preclinical and clinical data for other applications demonstrate safety and efficacy of MSCs, many issues still surround the mechanism of action. Concerns exist regarding the therapeutic efficacy of transplanted cells and the mechanism of engraftment, homing, and in vivo differentiation. Long-term safety studies are also still needed. Scale-up of stem cell culture, storage, and distribution will also be an issue when a greater demand for stem cell therapy arises.