Mesenchymal stem cells as trophic mediators in cartilage regeneration

Partial replacement of chondrocytes with stem cells in autologous chondrocyte implantation (ACI) has been proposed as an effective strategy to avoid the in vitro expansion phase of chondrocytes. This expansion phase is necessary to obtain sufficient cells for implantation after harvesting of the cartilage biopsy from the diseased joint. The partial replacement of chondrocytes with stem cells has the potential to bring back the current 2-step surgical procedure to 1-step surgery. Preliminary studies showed that co-culture of primary chondrocytes with various sources of multipotent stem cells increases the relative amount of cartilage matrix formation compared to monocultures of chondrocytes. The molecular mechanism of this chondro-inductive effect is not known. The aim of this thesis is to provide answers to this question.