Hydroxylapatite-collagen hybrid scaffold induces human adipose-derived mesenchymal stem cells to osteogenic differentiation in vitro and bone regrowth in patients

Abstract

Abstract Tissue engineering-based bone graft is an emerging viable treatment modality to repair and regenerate tissues damaged as a result of diseases or injuries. The structure and composition of scaffolds should modulate the classical osteogenic pathways in human stem cells. The osteoinductivity properties of the hydroxylapatite-collagen hybrid scaffold named Coll/Pro Osteon 200 were investigated in an in vitro model of human adipose mesenchymal stem cells (hASCs), whereas the clinical evaluation was carried out in maxillofacial patients. Differentially expressed genes (DEGs) induced by the scaffold were analyzed using the Osteogenesis RT2 PCR Array. The osteoinductivity potential of the scaffold was also investigated by studying the alkaline phosphatase (ALP) activity, matrix mineralization, osteocalcin (OCN), and CLEC3B expression protein. Fifty patients who underwent zygomatic augmentation and bimaxillary osteotomy were evaluated clinically, radiologically, and histologically during a 3-year follow-up. Among DEGs, osteogenesis-related genes, including BMP1/2, ALP, BGLAP, SP7, RUNX2, SPP1, and EGFR, which play important roles in osteogenesis, were found to be upregulated. The genes to cartilage condensation SOX9, BMPR1B, and osteoclast cells TNFSF11 were detected upregulated at every time point of the investigation. This scaffold has a high osteoinductivity revealed by the matrix mineralization, ALP activity, OCN, and CLEC3B expression proteins. Clinical evaluation evidences that the biomaterial promotes bone regrowth. Histological results of biopsy specimens from patients showed prominent ossification. Experimental data using the Coll/Pro Osteon 200 indicate that clinical evaluation of bone regrowth in patients, after scaffold implantation, was supported by DEGs implicated in skeletal development as shown in “in vitro” experiments with hASCs. Significance statement Bone regrowth can be achieved using different scaffolds. Biomaterials provide structural and biological cues to stem cells to stimulate the osteogenic differentiation. The new knowledge on the mechanisms of bone repair is of paramount importance to address significant steps needed in translational and precise medicine to cure patients. The hybrid scaffold Pro Osteon200/Avitene Collagen showed a significant osteogenic induction. The continuous supply of human adipose-derived mesenchymal stem cells for bone regrowth/remodeling, chondrogenic, and osteoclast activities with their epigenetic modulations have been disclosed herein. The new data of this study indicate that the continuous expression of osteogenic, osteoclastic, and chondrogenic genes favors bone regrowth.