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Background Systemic disorganisation of connective tissue with early metabolic disorder of its matrix is an inherent characteristic feature of rheumatoid arthritis (RA). The determination of the key extracellular matrix molecules in patients with early RA can adequately characterise a metabolism of connective tissue, stage of its destruction and the duration. Objectives to evaluate the significance of bone-cartilage resorption as an integral indicator of inflammatory-destructive processes in patients with early RA Methods We included 168 patients with early RA. The quantitative content and qualitative composition of glycosaminoglycans (GAG) in blood serum and excretion of GAG in urine were evaluated. Oxiproline (OP) and its fractions (free OP), protein-bound (OPp) and hydroxyproline were determined in serum and urine. The presence of antibodies to the cyclic citrullinated peptide (ACPA) was studied, as well as the C-terminal telopeptides of serum collagen I (CTX). Results We identified the results of excretion of GAGs in urine depending on disease activity. And according to our data, in patients with low inflammatory process (IP) the level was – 6.31±1.09 mg/g of creatinine (CR); moderate IP – 5.21±1.20 mg/g of CR, and high disease activity – 6.53±0.96 mg/g of CR. All these results were significantly higher in comparison with the control group by 55.9%, 29.1% and 67.7%, respectively. It means that GAG excretion rate did not depend on the stage of disease activity in patients with early RA, although even with a minimal IP it was significantly higher than normal. At the same time, the fractional composition of excreted GAGs in the urine in RA patients varied, as evidenced by a significant decrease in the sulfated GAGs content by 35% compared to the control group, although the differences between the groups were statistically unreliable. CTX also proved to be 2.86 times higher than the level of healthy persons in whom the indicated index was 0.15 ng/ml. In addition to a statistically significant increase of serum concentration of OP as compared to practically healthy persons, the qualitative composition of its fractions also changes, as evidenced by a significant elevation of OPp by 167.81%. No significant differences were found in the evaluation of OPfree and hydroxyproline Conclusions Progression of RA is accompanied by a progressive loss of the main functionally significant components of the extracellular matrix and manifested by a significant increase in the concentrations of proteoglycans and oxyproline. The level of C–terminal telopeptides of type I of serum collagen – was elevated even in patients with early RA, indicating the activity of bone resorption processes. The concentration and qualitative composition of blood serum GAGs adequately reflect the clinical symptoms of RA, being a sensitive integral test that reliably indicates the severity of inflammatory and destructive changes. Reference [1] Garnero P, Gineyts E, Christgau S, et al. Association of baseline levels of urinary glucosyl-galactosyl-pyridinoline and type II collagen C-telopeptide with progression of joint destruction in patients with early rheumatoid arthritis. Arthritis Rheum2002;46:21–30. Acknowledgements None Disclosure of Interest None declared |
