Autologous and heterologous adipose derived stem cells seeded on oligo(polyethylene glycol) fumarate hydrogel scaffold are effective in the regeneration of critical osteochondral defects in minipig model

Adipose-derived stem cells (ASCs), with their wide availability and multidiffferentiative potential, may represent an efficient tool for bone and cartilage regeneration. In this study ASCs were isolated from seven adult minipigs, expanded in culture and used in association with a oligo( polyethylene glycol) fumarate hydrogel scaffold (OPF) for the regeneration of critical osteochondral defects. Four defects (diameter 9 mm; depth 8 mm) were made on the peripheral part of the trochlea in each animal and treated with OPF scaffold which was pre-seeded with autologous or heterologous ASCs or used as cell-free. Empty defects were considered as negative control. Each isolated ASCs population was also tested in vitro. Six months after implantation, all samples showed quite satisfactory filling of the lesions, with the exception of one animal, whose joint appeared to be infected at the moment of harvesting. Good osteointegration was also observed by MRI evaluation. As revealed by histological and immunohistological analyses, OPF+ASCs constructs were able to promote a complete regeneration of the subchondral bone and a cartilage-like tissue. No differences were observed between autologous and heterologous constructs, thus supporting the possibility of an allogeneic use of this cell source. These results demonstrated that ASCs-OPF constructs has the potential for being considered a treatment option for the regeneration of osteochondral defects.