[Components of the extracellular tissue matrix as potential "markers" of connective tissue, cartilage and bone metabolism in diseases of the locomotor system].

Inflammatory and degenerative joint diseases are characterized by active degradation of the extracellular matrix of articular cartilage, bone and connective tissue. At the same time, specific changes in the neosynthesis of extracellular matrix components are seen. Thus, quantitative measurement of matrix related compounds and their metabolites in body fluids might provide a specific and sensitive tool for evaluating connective tissue involvement in rheumatic joint disease. The different components are linked to and may as such reflect different pathways of the pathological process, e.g.: Serum hyaluronan and serum procollagen type III peptides: fibroblast activation, early and late stage, respectively fibroproliferative tissue reaction. Synovial proteoglycans and glycosaminoglycans: degradation of proteoglycans derived from the extracellular matrix of cartilage; degree and activity of articular cartilage destruction. Serum keratan sulphate: proteoglycan metabolism (?). Urinary hydroxy pyridinium crosslinks (pyridinoline and deoxypyridinoline): degradation of mature cartilage and bone collagens; cartilage and bone catabolism. Cross-sectional and longitudinal clinical studies have shown that the quantitative measurement of some of these components may be of relevance in monitoring connective tissue disease. Further prospective studies are needed to prove the definite value of extracellular matrix-related components in early diagnosis and follow up of rheumatic joint and bone disease.