The main goal of my research is the identification of cell secreted factors that either stimulate or inhibit the endochondral ossification process. More specifically, by comparing the secretion pattern of mesenchymal stem cells, articular cartilage in health and during osteoarthritis. These factors then will be analysed on their capabilities to impact on mineralization, vessel formation and migration as well as osteoprogenitor recruitment. This will further be supported by mass-spectroscopy. As an additional method of selecting promising candidates that impact the differentiation capability of chondrocytes, existing microarray datasets will be used. These show the gene expression profile of healthy and osteoarthritic chondrocytes, growth plate chondrocyte and the development of cartilage in murine models.