Evaluation of Colonic Mucosa of Non-IBS And Non-Endoscopic Large Bowel Disorders in Metabolic Syndrome

Abstract

Background: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. Metabolic syndrome (MetS) is suspected to play a pro-inflammatory role in colonic mucosal microenvironment.

Aim of the work: To evaluate the mucosal histopathological and histochemical alterations of the colonic mucosa in metabolic syndrome (MetS) patients with non-organic and non-IBS large bowel disorders.

Patients and Methods: This cross-sectional study analyzed 199 symptomatic adults with normal colonoscopy findings, classified into four groups based on Rome IV criteria and MetS guidelines: Group I (IBS without MetS, n=47), Group II (IBS with MetS, n=80), Group III (non-IBS with MetS, n=49), and Group IV (non-IBS without MetS, n=23). Biopsies obtained from the right and left colon underwent blinded histopathological analysis to grade mucosal cellular infiltrates and architectural features.
Results: In the left colon, lymphocyte cellular infiltrate (LCI) differed significantly among the groups (p = 0.002), with moderate-to-severe grades predominantly clustered in Group II (15.0%) compared to Group I (2.1%) and Group III (6.1%). Significant pairwise LCI differences were verified between Groups I vs. II (p < 0.001) and II vs. III (p = 0.038). In the right colon, abnormal eosinophil cellular infiltrate (ECI) was significantly more frequent in Group II than Group III (21.3% vs. 6.1%, p = 0.049). A verified positive correlation was identified between LCI and MetS parameters in both the left colon (rho = 0.261, adjusted p = 0.003) and right colon (rho = 0.200, adjusted p = 0.032).

Conclusion: Metabolic syndrome acts as a histological catalyst, inducing distinct mucosal low-grade inflammation (especially lymphocytic infiltration) in patients with IBS functional bowel symptoms.