Colonic Mucosa Barrier Defects in Collagenous and Ischemic Colitis

Aims The subepithelial myofibroblasts (SEMFs) and the subepithelial band of macrophages (SEBM) are major components of the colonic mucosa barrier. Although their role in homeostasis is widely recognized, their contribution to disease states is largely unknown. The aim of the study was to explore histological characteristics of SEMFs and SEBM in collagenous and ischemic colitis.Methods Ten colonic biopsies of collagenous colitis, 10 of ischemic colitis and 10 control biopsies of normal mucosa were examined. SEMFs, SEBM and lamina propria macrophages were identified immunohistochemically by aSMA and CD68 respectively.ResultsIn collagenous colitis, SEMFs were rarely detectable in the collagenous band while in the lower lamina propria cell processes were formed. SEBM was preserved in areas with a collagenous layer up to 20μm. In thicker layers, it was fragmented and gradually disappeared in parallel with engulfment of enlarged macrophages. In the lower lamina propria macrophages were usually increased.In ischemic colitis, rounding, disintegration and extinction of SEMFs constituted successive alterations coinciding with crypt shrinkage and denudation. SEBM displayed total or almost total abolishment in areas with crypt damage and stroma fibrosis but also in sights with minimal changes.ConclusionIn collagenous colitis, alterations of mucosa barrier are related to collagenous layer thickness. SEMFs changes probably reflect derangement of differentiation and migration while SEMB alterations seem to be compensated by macrophage activation and numerical increase in lamina propria. The striking damage of mucosa barrier in ischemic colitis is indicative of its high sensitivity to hypoxia and hypoperfusion. The histological differences between collagenous colitis and ischemic colitis may be proven of differential diagnostic significance.

Severe acute ischemic colitis: What is the place of endoscopy in the management strategy?

Background and study aims Ischemic colitis (IC) is potentially lethal. Clinical and biology information and results of computed tomography (CT) scan and/or colonoscopy are used to assess its severity. However, decision-making about therapy remains a challenge. Patients and methods This was a retrospective, single-center study between 2006 and 2015. Patients with severe IC who underwent endoscopic evaluation were included. The aims were to determine outcomes depending on endoscopic findings and assess the role of endoscopy in the management. Results A total of 71 patients were included (men = 48 (68%), mean age = 71 ± 13 years). There was hemodynamic instability in 29 patients (41 %) and severity signs on CT scan in 18 (38 %). Twenty-nine patients (41 %) underwent surgery and 24 (34 %) died. The endoscopic grades were: 15 grade 1 (21 %), 32 grade 2 (45 %), and 24 grade 3 (34%). Regarding patients with grade 3 IC, 55 % had hemodynamic instability, 58 % had severity signs on CT scan, 68 % underwent surgery, and 55 % died. The decision to perform surgery was based on hemodynamic status in 62 % of cases, CT scan data in 14 %, endoscopic findings in 10 %, and other in 14 %. Colectomy was more frequent in patients with grade 3 IC (P < 0.05). A mismatch between mucosal aspect (necrosis) and serous (normal) was observed in 13 patients (46 %). Risk factors for colectomy in univariate analysis were aortic aneurysm surgery, hemodynamic instability, no colic enhancement on CT scan, and endoscopic grade 3. Risk factors for mortality in multivariate analysis were hemodynamic instability, colectomy, and Charlson score > 5 (P < 0.05). Conclusions This study suggests a low impact of endoscopy on surgical decision making. Hemodynamic instability was the first indication for colectomy. A discrepancy between endoscopic mucosal (necrosis) and surgical serous (normal) aspects was frequently noted.