Deciphering the Involvement of Chronic Inflammation in Osteoarthritis: Evaluation of Complement 3 and Cathepsin D in Osteoarthritic Patients—A Retrospective Case Study

Abstract

Background and Aim: Osteoarthritis (OA) stands as the prevailing degenerative joint condition, and although it is widely observed, its precise causes are not fully understood. The main focus of the study was to assess the role of Complement C3 and Cathepsin D in the development of knee osteoarthritis (OA), which is the most prevalent degenerative joint disease. Materials and Methods: The study was carried out in 20 patients with knee OA and 20 healthy control group. OA knee (Grade II/III, Radiological Kellgren and Lawrence (K/L) classification), aged between 40 and 65 years were able to walk with a painful knee. The study also included healthy age-matched controls. The concentration of Complement C3 and Cathepsin D in serum was determined. Results: The results of the present study demonstrated significantly (P < 0.001) higher concentrations of C3 and Cathepsin D in OA patients in comparison to that of the healthy aged matched control group. Conclusions: The analysis showed that inflammatory markers, Complement C3 as well as Cathepsin D may be used as diagnostic markers of knee OA. The observations suggest that the activation of the complement system mainly affects processes within the joints, while C3 appears to play a central role in generating a systemic inflammatory response.