Melena Revealing an Attenuated Familial Adenomatous Polyposis in an Elderly Patient: A Case Report

We describe a patient who was diagnosed with multiple tubulleuvillous adenomas with focus of high-grade tubular dysplasia all over the colonic mucosa, discovered during a colonoscopy performed during an episode of melena. Genetic testing has identified a germline truncating mutation at the codon (5q22.2) of the adenomatous polyposis (APC) gene. This mutation is localized in the alternately spliced region of exon 12, a region which is associated with an attenuated familial adenomatous polyposis (PAFA) phenotype. Our patient had no extracolic manifestations of PAFA and none of her relatives had a history of rectocolic polyposis. Treatment consisted of colectomy with ileorectal anastomosis. PAFA is an ill-defined condition of unknown prevalence and penetrance, requiring individual treatment and lifelong monitoring. It is essential to identify these patients with a view to setting up appropriate endoscopic surveillance at an early age in family members carrying this mutation, due to the marked intra-family phenotypic variance.

Delta opioid receptors on nociceptive sensory neurons mediate peripheral endogenous analgesia in colitis

Background Inflammatory visceral pain is endogenously controlled by enkephalins locally released by mucosal CD4+ T lymphocytes in mice. The present study aimed at identifying opioid receptor(s) expressed on nociceptive sensory nerves involved in this peripheral opioid-mediated analgesia. Methods The peripheral analgesia associated with the accumulation of CD4+ T lymphocytes within the inflamed colonic mucosa was assessed in conditional knockout mice specifically deleted for either of the two opioid receptors for enkephalins (i.e., µ (MOR) and δ (DOR) receptors) in Nav1.8-expressing sensory neurons in the dextran sulfate sodium (DSS)-induced colitis model. Results Endogenous analgesia is lost in conditional knockout mice for DOR, but not MOR at the later phase of the DSS-induced colitis. The absence of either of the opioid receptors on sensory nerves had no impact on both the colitis severity and the rate of T lymphocytes infiltrating the inflamed colonic mucosa. Conclusion The key role of DOR on primary afferents in relieving intestinal inflammatory pain opens new therapeutic opportunities for peripherally restricted DOR analgesics to avoid most of the side effects associated with MOR-targeting drugs used in intestinal disorders.

Importance of Eosinophilic Infiltration of the Colonic Mucosa in Ulcerative Colitis Patients who are Refractory to Maintenance Therapy

Eosinophilic infiltration is sometimes observed histologically in ulcerative colitis (UC), but the effect of the degree of infiltration on the treatment course for UC is not completely studied. We investigated whether short-term steroid administration in UC patients refractory to maintenance therapy, with high eosinophilic infiltration in the colonic mucosa, contributed to clinical and endoscopic improvement. Ten patients with endoscopically active and pathologically high eosinophilic infiltration, based on pathological examination using endoscopic biopsy, were examined for clinical background when starting steroid treatment; clinical and endoscopic improvement before and after steroid use were assessed prospectively. The average initial steroid dosage and duration of use were 21.0 mg and 102.7 days, respectively. The mean values before and after steroid use of clinical activity index, Mayo endoscopic subscore, and UC endoscopic index of severity were 2.4 and 1.0, 1.8 and 0.7, and 3.9 and 1.1, respectively. All these scores improved significantly after steroid use (P=0.04, P<0.01, P<0.01, respectively). Steroids were discontinued in all patients; no patients required steroid re-administration. There may be cases of UC with eosinophilic infiltration into the colonic mucosa and resistant to maintenance treatment, suggesting that short-term steroid administration may contribute to clinical and endoscopic improvements.

Early-Life Nutrition Interventions Improved Growth Performance and Intestinal Health via the Gut Microbiota in Piglets

Intestinal infections in piglets are the main causes of morbidity before and after weaning. Studies have not explored approaches for combining pre-weaning and post-weaning nutritional strategies to sustain optimal gut health. The current study thus sought to explore the effects of early-life nutrition interventions through administration of synthetic milk on growth performance and gut health in piglets from 3 to 30 days of age. Twelve sows were randomly allocated to control group (CON) and early-life nutrition interventions group (ENI). Piglets were fed with the same creep diet from 7 days of age ad libitum. Piglets in the ENI group were provided with additional synthetic milk from Day 3 to Day 30. The results showed that early-life nutrition interventions improved growth performance, liver weight, spleen weight, and reduced diarrhea rate of piglets after weaning (P &lt; 0.05). Early-life nutrition interventions significantly upregulated expression of ZO-1, Occludin, Claudin4, GALNT1, B3GNT6, and MUC2 in colonic mucosa at mRNA level (P &lt; 0.05). Early-life nutrition interventions reduced activity of alkaline phosphatase (AKP) in serum and the content of lipopolysaccharides (LPS) in plasma (P &lt; 0.05). The number of goblet cells and crypt depth of colon of piglets was significantly higher in piglets in the ENI group relative to that of piglets in the CON group (P &lt; 0.05). The relative mRNA expression levels of MCP-1, TNF-α, IL-1β, and IL-8, and the protein expression levels of TNF-α, IL-6, and IL-8 in colonic mucosa of piglets in the ENI group were lower compared with those of piglets in the CON group (P &lt; 0.05). Relative abundance of Lactobacillus in colonic chyme and mucosa of piglets in the ENI group was significantly higher relative to that of piglets in the CON group (P &lt; 0.05). Correlation analysis indicated that abundance of Lactobacillus was positively correlated with the relative mRNA expression levels of ZO-1, Claudin4, and GALNT1, and it was negatively correlated with the level of MCP-1 in colonic chyme and mucosa. In summary, the findings of this study showed that early-life nutrition interventions improved growth performance, colonic barrier, and reduced inflammation in the colon by modulating composition of gut microbiota in piglets. Early-life nutrition intervention through supplemental synthetic milk is a feasible measure to improve the health and reduce the number of deaths of piglets.

A Necessary Role for Increased Biglycan Expression during L1-Mediated Colon Cancer Progression

Aberrant activation of Wnt/β-catenin signaling and downstream β-catenin-TCF target genes is a hallmark of colorectal cancer (CRC) development. We identified the immunoglobulin-like cell adhesion receptor L1CAM (L1) as a target of β-catenin-TCF transactivation in CRC cells. Overexpression of L1 in CRC cells confers enhanced proliferation, motility, tumorigenesis, and liver metastasis, and L1 is exclusively localized at invasive areas of human CRC tissue. Several genes are induced after L1 transfection into CRC cells by a mechanism involving the L1-ezrin-NF-κB pathway. We conducted a secretomic analysis of the proteins in the culture medium of L1-overexpressing CRC cells. We detected a highly increased level of biglycan, a small leucine-rich ECM component, and a signaling molecule. We found that induction of biglycan is required for the cellular processes conferred by L1, including enhanced proliferation, motility, tumorigenesis, and liver metastasis. The suppression of endogenous biglycan levels or a point mutation in the L1 ectodomain that regulates cell–cell adhesion mediated by L1 blocked the enhanced tumorigenic properties conferred by L1. The mechanism of biglycan induction by L1 involves the L1-NF-κB pathway. Blocking NF-κB signaling in L1 expressing cells suppressed the induction of biglycan and the tumorigenic properties conferred by L1. Biglycan expression was undetectable in the normal colonic mucosa, but expressed at highly increased levels in the tumor tissue, especially in the stroma. The therapeutic strategies to target biglycan expression might provide a useful approach for CRC treatment in L1-overexpressing tumors.

Using a ligate intestinal loop mouse model to investigate Clostridioides difficile adherence to the intestinal mucosa in aged mice

Interaction of Clostridioides difficile spores with the intestinal mucosa contributes to the persistence and recurrence of the infection. Advanced age is one of the main risk factors for C. difficile infection and recurrence of the disease. However, interaction of C. difficile spores with the intestinal mucosa during aging has not been evaluated. In the present work, using intestinal ligated loop technique in a mouse model, we analyzed C. difficile spore adherence and internalization to the ileum and colonic mucosa during aging. Additionally, we provide visual documentation of the critical steps of the procedure. Consequently, our data suggest that spore internalization in the ileum and colonic mucosa is higher in elderly mice rather than adults or young mice. Also, our data suggest that spore adherence to the ileum and colonic mucosa decreases with aging.

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.

Colonic Mucosa-associated Mycobiota in Individuals With Normal Colons

To characterize the spatial variation of the mucosa-associated adherent mycobiota along the large intestine in individuals with a normal-colon, we performed eukaryotic rRNA operon’s internal transcribed spacer-2 sequencing to profile fungal community composition and structure in 70 mucosal biopsies taken from the cecum, ascending, transverse, descending colon, and rectum of 14 polyp-free individuals. The bacteriome of these samples was previously characterized by sequencing the V4 region of the 16S rRNA gene. We identified 64 amplicon sequence variants (ASVs) with the relative abundance no less than 0.05% from these colonic mucosa samples. Each individual has a unique community composition of the gut mycobiome (P = 0.001 for beta diversity). Alpha-diversity and beta-diversity did not differ significantly across the colon segments. The most common phyla (relative abundance) were Ascomycota (45.4%) and Basidiomycota (45.3%). The most common genera were Malassezia (28.2%) and Candida (13.4%). Malassezia was found in 13 of 14 individuals. Other fungi genera were sporadically found in the large intestine. The most common species were Malassezia restricta (22.7%), Candida albicans (11.9%), Malasseziales sp. (8.80%), unclassified fungi (7.80%), and Penicillium paneum (5.70%). Malasseziaceae was co-abundant with Enterobacteriaceae and co-exclusive with Barnesiellaceae, Rikenellaceae, and Acidaminococcaceae. Malassezia was widely colonized whereas other fungal genera were sporadically colonized in the large intestine. The physiologic and pathogenic functions of fungi in human gastrointestinal tract including Malasseziaceae that may interact with several bacterial families remain to be fully elucidated.

Role of microRNAs in the Pathophysiology of Ulcerative Colitis

Ulcerative colitis (UC) is an intractable disorder characterized by a chronic inflammation of the colon. Studies have identified UC as a multifactorial disorder affected by both genetic and environmental factors; however, the precise mechanism remains unclear. Recent advances in the field of microRNA (miRNA) research have identified an association between this small non-coding RNA in the pathophysiology of UC and altered miRNA expression profiles in patients with UC. Nevertheless, the roles of individual miRNAs are uncertain due to heterogeneity in both research samples and clinical backgrounds. In this review, we focus on miRNA expression in colonic mucosa where inflammation occurs in UC and discuss the potential roles of individual miRNAs in disease development, outlining the pathophysiology of UC.