Mesenchymal Stem Cells: New Insights into Bone Regenerative Applications

Bone is a dynamic tissue that possesses a significant healing capability. However, large bone defects arising from diseases or traumas require tissue-engineering applications. Currently, autografting of bone is extensively employed in orthopedic surgeries but presents serious limitations including donor site morbidity, rejection, and limited tissue regeneration. For these reasons, there is an immediate need for alternative treatments. Adult mesenchymal stem cells (MSC), capable to differentiate into osteoblasts, used in combination with scaffolds and growth factors provide a valuable tool for guided bone regeneration, especially for complex anatomic defects. Moreover, recent approaches of cell therapy lean on the broad spectrum of bioactive molecules, including trophic factors, angiogenic factors, anti-apoptotic molecules and immunomodulators secreted by MSCs. These factors might create a favourable regenerative microenvironment localized to sites of bone injury. In this review, we approach the current progresses on cell therapy that provides strong support for the clinical translation of MSCs for bone regeneration. We focus on: (1) defining the optimal combination of cell candidates, and biodegradable matrix scaffolds and (2) discussing the various effects that MSCs may exert on bone repair.