Maresin-1 and maresin-2 as synovial fluid biomarkers in psoriatic, rheumatoid, and osteoarthritis

Objective – To investigate synovial fluid levels of maresin-1 (MaR-1) and maresin-2 (MaR-2) in patients with psoriatic arthritis (PsA), rheumatoid arthritis (RA), osteoarthritis (OA), and controls, and to assess their ability to differentiate PsA from RA. Methods – This prospective cross-sectional study included 88 patients undergoing knee arthrocentesis for joint effusion between September 2025 and February 2026. RA was classified according to the 2010 ACR/EULAR criteria, PsA using CASPAR criteria, and OA based on clinical and radiographic assessment. Synovial fluid MaR-1 and MaR-2 concentrations were measured by enzyme-linked immunosorbent assay (ELISA) and expressed as ng/mL. Group comparisons were performed using parametric or non-parametric statistical tests as appropriate. Receiver operating characteristic (ROC) curve analysis evaluated the diagnostic performance of MaR-1 and MaR-2 for distinguishing PsA from RA, including area under the curve (AUC), sensitivity, specificity, and optimal cut-off values. Logistic regression analysis assessed the association between MaR-1 levels and PsA. Results – Significant intergroup differences were observed for age, visual analogue scale (VAS) scores, and synovial MaR-1 concentrations (all p < 0.01). MaR-1 levels were significantly higher in PsA than RA (p < 0.01), whereas MaR-2 showed more modest differences among groups (p < 0.05). ROC analysis demonstrated good discriminatory performance of MaR-1 for differentiating PsA from RA, with an AUC of 0.815 (95% CI, 0.675–0.933). A cut-off value of 3.252 ng/mL provided 68.2% sensitivity and 86.4% specificity. Higher MaR-1 levels were significantly associated with PsA in unadjusted logistic regression analysis (OR = 1.62, 95% CI 1.18–2.22; p = 0.003). MaR-1 and MaR-2 levels were moderately positively correlated (Spearman’s r = 0.620, p < 0.001). Conclusion – Synovial MaR-1 concentrations were markedly elevated in PsA compared with RA and demonstrated good diagnostic discrimination, supporting the potential role of pro-resolving mediators as biomarkers in inflammatory arthropathies. The clinical significance of MaR-2 appears more limited and requires validation in larger studies. Copyright © 2026 Demir, Can, Esmez, Aydin, Gencer, Bildirici, Koca, Sahin and Aydin.