Proper bony tissue regeneration requires mechanical stabilization, an osteogenic biological activity and appropriate scaffolds. The latter two elements can be combined in a hydrogel format for effective delivery, so it can readily adapt to the architecture of the defect. We evaluated a Good Manufacturing Practice-compliant formulation composed of bone marrow-derived mesenchymal stromal cells in combination with bone particles (Ø = 0.25 to 1 µm) and fibrin, which can be readily translated into the clinical setting for the treatment of bone defects, as an alternative to bone tissue autografts. Remarkably, cells survived with unaltered phenotype (CD73⁺, CD90⁺, CD105⁺, CD31⁻, CD45⁻) and retained their osteogenic capacity up to 48 h after being combined with hydrogel and bone particles, thus demonstrating the stability of their identity and potency. Moreover, in a subchronic toxicity in vivo study, no toxicity was observed upon subcutaneous administration in athymic mice and signs of osteogenesis and vascularization were detected 2 months after administration. The preclinical data gathered in the present work, in compliance with current quality and regulatory requirements, demonstrated the feasibility of formulating an osteogenic cell-based tissue engineering product with a defined profile including identity, purity and potency (in vitro and in vivo), and the stability of these attributes, which complements the preclinical package required prior to move towards its use of prior to its clinical use.

正确的骨组织再生需要机械稳定，成骨生物学活性和适当的支架。后两个元素可以以水凝胶形式组合以有效递送，因此它可以轻松适应缺陷的结构。我们评估了符合《良好生产规范》的配方，该配方由骨髓来源的间充质基质细胞与骨颗粒（Ø= 0.25至1 µm）和纤维蛋白组成，可轻松转化为临床治疗骨缺损的方法，作为自体骨组织的替代物。值得注意的是，细胞存活，不变的表型（CD73 ⁺，CD90 ⁺，CD105 ⁺，CD31 ^-，CD45 ^-）并与水凝胶和骨颗粒结合后最多保持48小时的成骨能力，从而证明其身份和效能的稳定性。此外，在体内亚慢性毒性研究中，无胸腺小鼠皮下给药未观察到毒性，给药后2个月未检测到成骨和血管形成的迹象。在当前工作中收集的临床前数据符合当前的质量和法规要求，证明了配制具有确定特性的成骨细胞基组织工程产品的可行性，该特性包括身份，纯度和效力（体外和体内），以及这些属性的稳定性，可以补充临床使用之前需要使用的临床前包装。