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.

Patients With Microscopic Colitis Have Altered Levels of Inhibitory and Stimulatory Biomarkers in Colon Biopsies and Sera Compared to Non-inflamed Controls

Introduction: Microscopic colitis (MC) is an inflammatory bowel condition with two subtypes, lymphocytic colitis (LC) and collagenous colitis (CC). Unlike patients with ulcerative colitis (UC) and non-inflamed individuals, MC patients have reduced risk of developing colorectal cancer, possibly due to increased immune surveillance in MC patients.Aim: To examine differences in levels of immunomodulatory molecules, including those involved in immune checkpoint mechanisms, in sera from patients with MC and in colonic biopsies from patients with MC and UC compared with controls.Methods: Using Luminex, 23 analytes (4-1BB, 4-1BBL, APRIL, BAFF, BTLA, CD27, CD28, CD80, CTLA-4, E-cadherin, Galectin-3, GITR, HVEM, IDO, IL-2Rα, LAG-3, MICA, MICB, PD-1, PD-L1, PD-L2, sCD40L and TIM-3) were studied in serum from patients with active MC (n = 35) and controls (n = 23), and in colonic biopsies from patients with active LC (n = 9), active CC (n = 16) and MC in histological remission (LC n = 6, CC n = 6), active UC (n = 15) and UC in remission (n = 12) and controls (n = 58).Results: In serum, IDO, PD-1, TIM-3, 4-1BB, CD27, and CD80 were decreased whereas 4-1BBL and IL-2Rα were increased in MC patients compared with controls. In contrast, in biopsies, levels of PD-L2 and 4-1BB were increased in MC and UC patients with active disease. Furthermore, in biopsies from CC and UC but not LC patients with active disease, CTLA-4, PD-1, APRIL, BAFF, and IL-2Rα were increased compared with controls. PD-L1 was increased in CC but not UC or LC patients. CD27 and TIM-3 were decreased in biopsies from MC patients in comparison to controls whereas levels of MICB were decreased in patients with active UC compared with controls.Conclusions: Compared with non-inflamed controls, levels of soluble and membrane-bound immunomodulatory molecules were systemically and locally altered in MC and UC patients, with most analytes being decreased in serum but enhanced in colonic biopsies. These findings contribute to knowledge about checkpoint molecules and their role as biomarkers in MC and may also contribute to knowledge about possible mechanisms behind the seemingly protective effects of MC against colorectal cancer.

A Rare Medullary Carcinoma of Jejunum

Introduction/Objective Medullary carcinoma of jejunum is an extremely rare condition. These tumors account for less than 0.04% of all colorectal cancers and less than 3 cases to date has been reported in the small intestine Methods/Case Report We present a case of 78-year-old woman with a celiac disease and collagenous colitis, chronic diarrhea, chronic anemia and 2.1 cm apple core lesion on mid to distal jejunum on CT leading to partial obstruction. Results (if a Case Study enter NA) Histologically tumor showed invasive carcinoma in a solid growth pattern with pushing border. The tumor cells were uniform, enlarged with prominent nucleoli and brisk mitotic activity. There was prominent inflammatory response within and around the tumor. Immunohistochemical stains were positive for CK7, CDX2 CK19, CKAE1-3 and negative for CD45, CK20, Chromogranin Synaptophysin, PAX-8. MLH1 &PMS2 showed loss of nuclear expression and MSH2 & MSH6 with Intact nuclear expression. Microsatellite instability was High (MSI- H) with instability in two or more microsatellite markers. Diagnosis of medullary carcinoma of jejunum was made. Conclusion Although the clinical manifestations can be consistent with signs of intestinal obstruction, often these rare tumors are discovered incidentally. Conditions such as celiac disease, Crohn’s disease, and other chronic inflammatory illnesses have been linked to contributing risk factors. Imaging and appropriate tumor markers have less role in diagnosis; however, biopsy is needed for definitive diagnosis. Even though the development of these tumors in the small bowel is rare, further enhancement of awareness can aid in the appropriate early detection and appropriate treatment modalities.

Patterns and Utility of Calprotectin in Patients with Microscopic Colitis

Context Calprotectin is a cytoplasmic-protein that is released upon neutrophilic activation. Measuring fecal-calprotectin (FC) is used for monitoring inflammatory bowel disease activity and distinguishing it from irritable bowel syndrome. However, its utility in other types of colitis has not been well-investigated. Design Cases of collagenous-colitis (CC) and lymphocytic-colitis (LC) between 2015 and 2020 were retrieved from our institution surgical pathology database. Endoscopy and histopathologic examination findings were reviewed to confirm the diagnosis. 15 CC and 13 LC cases were included as FC was done at the time of initial diagnosis (before therapy). 62 cases of normal endoscopy and histopathologic examination were selected as a control group. One-way analysis of the variance (ANOVA) and receiver operating curve (ROC) analysis of FC were performed. Results Abnormally elevated FC (> 50 ug/g) was identified in 77% and 64% of CC and LC cases, respectively. Only 1.6% of control cases had mildly elevated FC of 54 ug/g. The mean FC of CC and LC groups (246 and 214, respectively) were significantly higher than the control group (22.4); p= <0.05. LC and CC groups had no statistically significant difference in the mean FC (p = 0.8). The area under the curve was 0.93 with ROC analysis. At the suggested cut-off of 50 ug/g, the sensitivity was 78.6%, specificity was 98.4% with a likelihood ratio of 48.7. Conclusions Fecal calprotectin can be elevated in patients with lymphocytic or collagenous colitis, however with no statistically significant difference between the two types. Therefore, it has the potential to be used as a marker for screening, diagnosis, and monitoring response to therapy in patients with microscopic colitis.