The Role of Serum Level of Col2a1 and Hyaluoronic Acid in Diagnosis of Knee Osteoarthritis

Osteoarthritis (OA) is a complex condition in which affected tissues experience changes in metabolism, structure, biochemistry, and function. This condition arises when chondrocytes fail to balance the synthesis and degradation of extracellular components like proteoglycans and collagens, leading to inflammation of the synovial membrane and joint capsule. Aim of the study: This study was designed to evaluate the serum levels of Type II Collagen alpha 1 (coll2a1) and Hyaluronic Acid (HA) in diagnosis of early stage of knee osteoarthritis in Iraqi patients Subjects and Methods: This case- control study was carried out at Department of Biochemistry, College of Medicine, University of Baghdad and at Rheumatology Department , Baghdad Hospital / Medical City, during the period from September 2022 to March 2023. It included ninety volunteer males and females subdivided into subgroups: Group 1consisted of 50 patients who have had early stages of knee osteoarthritis (KOA) and group 2 involved 40 apparently healthy subjects who served as control group. The diagnosis of KOA was made by a consultant rheumatologist using American College of Rheumatology (ACR) criteria. Moreover, patients were sub- classified according to their BMI (normal weight, overweight and obese) and KOA severity (grad1 and grad 2). Investigations included serum measurements of Human serum coll2a1( type II collagen alpha I) and Human serum HA (Hyaluronic Acid) in all patients and controls by ELISA technique. Results: The mean (±SD) values of Coll2a1, HA, of KOA patients were significantly higher than those of controls (for all, p <0.01). There was significant positive correlation between. The mean value of serum hyaluronic acid was significantly increased in grad 2 KOA when compared with grad 1 KOA patients (p < 0.004). The results found that fibulin-3 has the highest receiver operator characteristic (ROC) and area under curve (AUC=89.2% ) at cutoff (7.50 ng/ml) with sensitivity 80.0 and specificity 80.0 in diagnosis of KOA. Also, serum Coll2a1 has high diagnostic utility (AUC=88.6%) at cutoff (286.00 pg/ml) with sensitivity 82.0 and specificity 80.0 . Conclusion: Assessing non-invasive serum levels of coll2a1 (with a cutoff of 286.00 pg/ml) offers a new biochemical marker for diagnosing the early stages of knee osteoarthritis (KOA) potentially before changes become visible on X-rays. Additionally, measuring serum hyaluronic acid levels could serve as an indicator of disease severity, helping to differentiate between various grades of KOA.