Composite scaffolds composed of bone marrow mesenchymal stem cell-derived extracellular matrix and marrow clots promote marrow cell retention and proliferation

Various biomaterials have been investigated in attempts to improve the mechanical stability of marrow clots derived from microfracture to obtain repaired tissue closely resembling hyaline cartilage. The goal of this study was to investigate the retention, adhesion, proliferation, and cartilage extracellular matrix (ECM) production of marrow clot-derived cells within a bone marrow mesenchymal stem cell-derived (BMSC-d) ECM/marrow clot composite scaffold. We fabricated BMSC-dECM/marrow clot composite scaffolds and kept them in chondrogenic medium in vitro for 1, 3, or 6 weeks. Unmodified marrow clots were used as a control. The BMSC-dECM/marrow clot composite scaffold exhibited a porous structure suitable for cell attachment and growth and further maintained cell viability. The DNA content measurements revealed that more cells proliferated in the BMSC-dECM/marrow clot composite scaffolds over time than in the marrow clots. Furthermore, the histologic, immunohistochemical, and western blot results demonstrated that the BMSC-dECM/marrow clot composite scaffold produced more hyaline-like cartilage and less fibrocartilage than the marrow clot in culture. Taken together, these findings indicate that the porous BMSC-dECM/marrow clot composite scaffold promotes the retention, attachment, and proliferation of cells from the marrow clot, and thus can stabilize the marrow clot to support chondrogenesis.