Periosteum-derived scaffold free constructs for cartilage repair

Evidence suggests that periosteum contributes to fracture healing by acting as local source of skeletal progenitor cells which participate in endochondral bone formation (1,2). Nevertheless, the commitment of in vitro expanded human Periosteum-Derived Cells (hPDCs) towards a stable form of articular cartilage was not demonstrated yet. In this work we used members of the TGF-β/BMP superfamily of growth factors to modulate the kinetics of chondrogenic differentiation of PDCs and generate cell-based 3D constructs for cartilage tissue engineering purposes. Micromasses of hPDC's cultured for 28 days in chondrogenic medium supplemented with GFs displayed in vitro deposition of matrix glycosaminoglycans (GAGs), type-II, type-X, and type-I collagens. After 4 weeks of ectopic in vivo transplantation, ossicle-like tissues were retrieved with bone marrow, bone and mineralized cartilage, and after 8 weeks we found resorption of the newly formed bone and maintenance of the mineralized cartilage. Orthotopically, in an osteochondral defect model, µMasses have successfully engrafted at the defect's place and allowed subchondral bone formation and development of a GAG-rich, non-mineralized cartilage matrix. Therefore, we hypnotized that our strategy might contribute to restoring the subcondral and chondral areas upon full thickness osteochondral damage.