Co-Culture Approaches in Cartilage and Bone Tissue Regeneration.

Cartilage and bone defects as well as osteoarthritis are prevalent worldwide, affecting individuals across all age groups, from young, active populations to older adults. The standard protocol in cartilage regeneration involves knee replacement surgery through the implantation of an endoprosthesis. Current clinical protocols involving cell-based therapies are associated with limitations, including the lack of functional cartilage-like tissue and dedifferentiation of chondrocyte, particularly during monoculture. Similarly, in bone regeneration, the "gold standard" is the use of bone auto- or allografts, which are associated with immunological rejection, inadequate vascularization, and limited osteogenesis. To overcome these limitations, various co-culture techniques have been introduced as promising strategies for cartilage and bone tissue regeneration. These systems aim to mimic native microenvironments by promoting interactions between chondrocytes and mesenchymal stromal cells (MSCs) in cartilage repair and between osteogenic and angiogenic cells in bone regeneration. This paper introduces different co-culture systems focusing on in vitro crosstalk between MSCs derived from various sources and other somatic cell populations in cartilage and bone regeneration.