Correlation of Omentin-1 with Disease Extent and Therapeutic Response to Infliximab in Ulcerative Colitis

Background: Ulcerative colitis (UC) is classified by both activity and extent. Accumulating evidence suggests that disease extent is an independent factor in determining poor prognosis. However, there is a significant lack of blood biomarkers that mirror lesion reach, clinicians still rely on repeated endoscopy to determine disease activity and mucosal healing. Omentin-1 is an adipokine secreted mainly by visceral adipose tissue and intestinal goblet cells that has been reported to exert anti-inflammatory and epithelial-barrier-enhancing effects. Therefore, we hypothesized that serum omentin-1 correlates with disease extent and predicts primary response to infliximab (IFX). Methods: Consecutive UC patients (n = 126) were enrolled and stratified by Montreal classification into distal (E1/E2, n = 84) or extensive (E3, n = 42) disease. Serum omentin-1 was quantified by ELISA. Clinical activity (partial Mayo) and endoscopic activity (MES) were recorded. Among 36 subjects who received standard IFX induction, response was assessed at week 14. Results: Among the 126 UC patients, serum omentin-1 levels were significantly lower in extensive than distal colitis [median: 48.60 (38.28– 67.35) ng/mL vs 62.70 (58.48– 73.88) ng/mL, p < 0.01]. By controlling for clinical and endoscopic activity scores between groups, we found that serum omentin-1 levels differed between patients with different UC disease extents at the same level of disease activity, suggesting that serum omentin-1 can effectively predict the disease extent of UC independently of disease activity. In the IFX cohort (n = 36), responders (n = 23) exhibited higher baseline serum omentin-1 than non-responders. Extent-stratified analysis revealed that the discriminative capacity was confined to extensive colitis, with no significant predictive value in distal disease. Conclusion: Serum omentin-1 quantifies UC extent independently of activity and predicts IFX response specifically in extensive colitis, offering a blood-based tool to map disease extent and guide biologic therapy. This finding may reduce the reliance on repeated colonoscopy and support therapeutic stratification in extensive disease.