Bone non-union is one of the most challenging pathologies in orthopaedics surgery. Advanced cell therapy holds a considerable hope for the development of novel approaches to promote adapted cellular recolonization by optimal interaction with their micro-environment, including recruitment and differentiation of stem/progenitor cells for the restoration of the bone homeostasis. However, the direct application of MSCs remains limited in vivo by a low homing efficiency of the injected cells (alone or seeded on a scaffold) associated to a low survival rate at the implantation site. Several scaffold-free systems have been investigated but creating sufficient thickness to fill a critical size bone defect is difficult. We previously demonstrated the potential of a scaffold-free osteogenic 3-dimensional implant (obtained by the production of extracellular matrix from human autologous) to cure critical size bone defects in large animal models and humans. However, the possibility to predict the future clinical success of an advanced therapy of medicinal products is based on the assumption that the cell population and the ECM are fully characterized in vitro and in vivo. Here, we discuss the strategy to study the bioactivity of a scaffold-free osteogenic tissue-engineered products intended to promote angiogenesis and osteogenesis in a several types of bone defects.
Dufrane et al. (Mon,) studied this question.