BIOMARKERS OF BONE AND CARTILAGE REMODELING IN THE EVALUATION OF EARLY STAGES OF PRIMARY KNEE OSTEOARTHRITIS

Objective. To determine the informative value of biological markers of bone and cartilage remodeling in patients with early-stage primary knee osteoarthritis (KOA). Subject and methods. The investigation involved 43 patients (16 men and 27 women) aged 36-50 years with early manifestations of KOA and 21 apparently healthy individuals without locomotor diseases. The markers of bone tissue metabolism were determined in all the study participants: resorptive processes were assessed by the content of C-terminal telopeptides of type I collagen and pyridinoline; the intensity of bone formation processes was estimated by the level of osteocalcin. The concentrations of cartilage oligomeric matrix protein and cartilage glycoprotein were determined as markers of cartilage destruction. Results. The significantly elevated levels of cartilage oligomeric matrix protein and cartilage glycoprotein show evidence of articular cartilage disorganization in the examinees. In addition, there were impaired bone formation (higher osteocalcin levels) and resorption (an increase in the concentrations of C-terminal telopeptides of type I collagen and pyridinoline) processes compared with those in the control group. Conclusion. The patients with early signs of KOA without obvious clinical and radiographic manifestations were observed to have impaired bone remodeling as intensified bone formation and resorption processes, which was accompanied by cartilage matrix restructuring. An indirect assessment of the stability of the collagen network that forms the extracellular framework of the supporting connective tissues displayed a significant increase in serum pyridinoline concentrations, which could be evidence of disruption of intermolecular collagen bonds. The reliably significant changes in the content of pyridinoline suggest that this marker may be used to comprehensively evaluate the health status of patients with early manifestations of KOA when developing diagnostic and therapeutic strategies.