Our department has a long-lasting collaboration with TNO, Leiden, formerly called TNO Prevention and Health and presently TNO Knowledge for business. This collaboration is based on mutual synergistic expertise. TNO has its quality on biomarkers, proteases and collagens in cartilage and bone, fitting well with several of our research lines. There have been two successful PhD projects (DeGroot J and Verzijl N) and presently a 3rd and 4th PhD study on non enzymatic glycation (Vos P) and on biomarkers in early osteoarthritis (Spil v/d E) are ongoing.