[Show abstract][Hide abstract] ABSTRACT: Osteoarthritis (OA) is a primarily non-inflammatory, degenerative joint disease characterized by progressive loss of articular cartilage, subchondral bone sclerosis, osteophyte formation, changes in the synovial membrane, and an increased volume of synovial fluid with reduced viscosity and hence changed lubrication properties. As OA is the most common type of arthritis and a leading cause of disability, there is a largely unmet medical need for disease-modifying and symptomatic treatment. Due to the localized nature of the disease, intraarticular (IA) drug injection is an attractive treatment approach for OA. The various glucocorticoid and hyaluronic acid (HA) formulations, which are currently available on the market for IA treatment, provide only short-term pain relief or/and often do not provide adequate pain relief. The available oral drugs for symptomatic treatment also have shortcomings, most notably side effects. Therefore, there is still a large unmet need for novel OA drugs, which provide effective long-term pain relief and/or have disease-modifying properties. To achieve long-term drug exposure, different established formulations such as suspensions and hydrogels, and also novel approaches such as lipid based formulations and nano- or microparticles are currently in development. The development of novel drugs in combination with new formulations for IA treatment of OA, represents a promising approach in this challenging area of research.
[Show abstract][Hide abstract] ABSTRACT: Osteoarthritic (OA) cartilage degeneration and cartilage destruction in rheumatoid arthritis depends significantly on enzymatic degradation of cartilage proteoglycan aggrecan. A member of the ADAMTS family of proteases, ADAMTS-1 was described to have "aggrecanase" activity. We investigated the quantitative expression and distribution of ADAMTS-1 in healthy and OA cartilage and in cultured articular chondrocytes with and without stimulation by interleukin 1beta (IL-1beta) and insulin-like growth factor-I (IGF-I).
Conventional and online polymerase chain reaction (PCR) technology was used to determine ADAMTS-1 mRNA expression levels of ADAMTS-1. Protein was localized using immunostaining with different polyclonal antibodies.
Conventional and online semiquantitative PCR showed significant levels of ADAMTS-1 mRNA expression in normal and OA chondrocytes in vivo and in vitro. Only a slight increase was observed in OA cartilage. After stimulation with IL-1beta a downregulation of ADAMTS-1 was observed, whereas IGF did not appear to change mRNA expression levels in vitro. The in vivo mRNA expression results were confirmed by the presence of significant protein staining with antibodies for ADAMTS-1 in normal and OA chondrocytes as well as Western blotting analysis. Whereas a significantly stronger stain was seen in normal articular cartilage in the upper zones, in OA cartilage as well the middle zone showed enhanced staining.
Our results confirm the expression and presence of ADAMTS-1 in articular cartilage. However, they also point out that ADAMTS-1 appears to be constitutively expressed by adult articular chondrocytes and overall is not strongly upregulated in OA. Thus our data suggest that ADAMTS-1 is the first matrix-degrading enzyme downregulated by the catabolic factor IL-1beta in vitro.
The Journal of Rheumatology 03/2004; 31(2):315-20. · 3.17 Impact Factor