Doctor Department of Regenerative Science, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Japan., Japan
Abstract: Osteochondral defects are characterised by a limited capacity for self-repair, rendering treatment via regenerative medicine highly anticipated. However, challenges associated with regenerative medicine for osteochondral defects are primarily related to graft adhesion and the complexity of transplantation techniques. Human-induced pluripotent stem cell-derived expandable PRRX1+ limb bud mesenchymal cells, which function as human chondrocyte progenitor cells (hCPCs), were developed. The objective of this study is to establish a novel technique for cartilage regeneration by developing a paste-like, easily transplantable structure, designated as "Chondro-paste," which is composed of hCPCs and scaffolds. The differentiation of hCPCs into chondrocytes was induced through two-dimensional culture in 24-well culture plates or 10 cm Petri dishes. Subsequently, "Chondro-paste" was prepared by combining the cells with Mebiol gel(Ikeda), 2% methylcellulose(Wako), and a mixture of 5% gelatin methacrylate(CELLINK) and 1.2% alginate gel(Wako). Immunodeficient rats (F344-Il2rgem1Iexas) were used to create osteochondral defects on the femoral knee joint surface, and Chondro-paste was implanted using a 10 μL pipette. Four weeks after transplantation, Safranin O staining and immunostaining (human Vimentin, Aggrecan, and COL2) were performed on the grafts for histological evaluation. The growth of cartilage-like tissue resembling vitreous chondrocytes was observed within osteochondral defects in each application of Chondro-paste. The compatibility and continuity between the graft and the host osteochondral tissue were most effectively observed in the Chondro-paste containing 5% gelatin methacrylate and 1.2% alginate gel. hCPCs have the potential to differentiate into cartilage tissue when combined with a scaffold and transplanted into osteochondral defects. This study introduces a novel technique for cartilage regeneration using hCPCs and scaffolds, which can be transplanted in a straightforward and easily manageable manner. Further studies using larger animal models are necessary to validate the potential of Chondro-paste in treating osteochondral defects of different sizes and shapes.
Funding Source: This research was supported by the Grant-in-Aid for Scientific Research (C) from the Japan Society for the Promotional of Science (Grant Number 24K12308).
