Matrix metalloproteinase 9 and dipeptidyl peptidase-4/cluster of differentiation 26 are better performing biomarkers than matrix metalloproteinase 3 in stratifying mild and moderate activity of the ulcerative colitis

Introduction: Ulcerative colitis (UC) is an idiopathic, chronic inflammatory bowel disease with an unpredictable clinical course.Reliable biomarkers reflecting intestinal inflammation remain a clinical priority.The aim is to evaluate the matrix metalloproteinase's (MMP) 3, MMP9 and peptidase-4/ cluster of differentiation 26 (DPP4/CD26) discriminative ability between different stages of the UC and assess their association with disease activity.Material and methods: This cross-sectional study enrolled 40 patients with mild and moderate UC.Disease activity was assessed using Truelove-Witts, Ulcerative Colitis Endoscopic Index of Severity (UCEIS), and Mayo score, as well as histological evaluation.Biomarker concentrations were measured in serum samples.Discriminative ability was evaluated using receiver operating characteristic (ROC) analysis with area under the curve (AUC) and Youden-derived cut-off values.The association between biomarker concentrations and disease activity was assessed using Spearman's rank correlation coefficient.Results: MMP9 and DPP4/CD26 demonstrated comparable discriminative ability (AUC = 0.76, 95% confidence interval (CI): 0.60 to 0.88, P < 0.001; Cohen's d = 1.09 and AUC = 0.71, 95%CI: 0.54 to 0.84, P = 0.015; Cohen's d = 0.86, respectively).At the Youden-derived cut-off, MMP9 showed high sensitivity (80%) and moderate specificity (60%) to discriminate, whereas DPP4/CD26 showed lower sensitivity (45%) and high specificity (90%).MMP9 demonstrated statistically significant weak-to-moderate correlations with all disease activity tests (ρ = 0.41-0.49;P = 0.001-0.008),while MMP3 and DPP4/CD26 showed limited or inconsistent correlations.Conclusion: MMP9 and DPP4/CD26 displayed a significant difference between mild and moderate UC activity and demonstrated comparable discriminatory potential, although their combination does not enhance this feature.MMP9 showed a weak but significant association with disease activity, whereas MMP3 showed no clinical relevance.