Distal Colon Research Articles

ROS/pH dual-responsive quercetin-loaded guanosine borate supramolecular hydrogel enema in dextran sulfate sodium-induced colitis in mice.

Ulcerative colitis (UC) is an inflammatory bowel disease that predominantly impacts the colon, typically starting in the rectum. A significant characteristic of UC is its propensity to affect the distal colon, which is particularly beneficial for targeted treatments such as enemas. This localized approach ensures that the medication is delivered directly to the affected areas, resulting in minimal systemic absorption. In this research, we have formulated a novel stimuli-responsive quercetin-loaded guanosine borate supramolecular hydrogel (named GBQ hydrogel), designed to prolong the residence time of the drug and protect the ulcerated intestinal tissues. The GBQ hydrogel has exhibited excellent injectability, self-healing capabilities, and biocompatibility, rendering it an ideal candidate for enema administration. In vitro studies have highlighted its ROS/pH dual-responsive release profile, which mimics the microenvironment of intestinal inflammation. Furthermore, we assessed the efficacy of the GBQ hydrogel on dextran sulfate sodium (DSS)-induced colitis, a common animal model for UC. Our findings indicate that the GBQ hydrogel significantly reduces disease activity, mitigates oxidative stress, restores the intestinal mucosal barrier, and prevents colonic cell apoptosis. Collectively, this study underscores the therapeutic potential of the GBQ hydrogel in managing inflammatory bowel conditions and paves the way for a novel hydrogel enema-based treatment strategy for UC.

The Potential of Polysaccharides from Various Plants as Constipation Treatment

Constipation is one of the disorders of Irritable Bowel Syndrome (IBS). Lack of consumption of water and food with fiber are some of the causes of constipation. Treatment for constipation patients can be solved by administering laxatives through drugs (pharmaceuticals) or using polysaccharide parts from plants. There are at least three types of laxatives: bulking agents (having the ability to bulk up), osmotic agents, and stimulants. Polysaccharides can be sourced from whole or some parts of the plants. Each type of plant has different polysaccharide components, and their effects on constipation treatment are also specific. The study aimed to review the mechanisms of polysaccharides from various plants parts and explained the misconception of polysaccharide intake as a laxative agent in treating constipation. This review was based on literature studies related to polysaccharides from plants materials and their effects as laxatives in experimental animals. The review found that these polysaccharides have a positive effect as a laxative or digestive aid. In general, polysaccharides from several plants were extracted and characterized to be used as anti-constipation test materials. These polysaccharides can help increase the amount, weight, and water content of feces (bulk), increase peristalsis, speed up gastric emptying and transit time, as well as restore hormones that work in movement in the digestive tract, and improve the condition of the distal colon tissue. These studies are still limited to using animals as experimental test material in polysaccharides to treat constipation. In addition, it has the potential to be further explored regarding the possibility of clinical trials of polysaccharides in humans as laxatives.

Non-IgE-mediated food allergy

Food allergy is an immune response to proteins in food. It usually affects 8% of children and 2% of adults in Western countries. Non-IgE-mediated food allergy mainly affects the gastrointestinal tract. Gastrointestinal food allergies are classified, by their underlying pathogenesis, as: IgE-mediated, non-IgE-mediated, or mixed. The symptoms of patients with food protein-induced allergic proctocolitis originate from local inflammation of the distal colon, which causes hematochezia in neonates. It can affect the entire gastrointestinal tract and cause symptoms of intractable emesis, with subsequent metabolic disorders and hypovolemic shock. Food protein-induced enterocolitis syndrome is a non-IgE-mediated allergy that usually appears in childhood, with prolonged repetitive vomiting, starting 1 to 4 hours after ingestion of food. The manifestation in adults is usually triggered by the consumption of shellfish. Atopic diseases affect 40-60% of patients with food protein- induced enterocolitis syndrome, including 40-50% of those with food protein-induced enteropathy and proctocolitis. Probiotics (Lactobacillus GG) can alleviate the symptoms of allergic proctocolitis induced by food proteins, by altering the composition of the intestinal microbiota. Fecal microbiota transplantation (FMT) can change intestinal microecology efficiently compared to food or probiotics.

TRPV1 controls innate immunity during Citrobacter rodentium enteric infection.

Mucosal immunity is critical to host protection from enteric pathogens and must be carefully controlled to prevent immunopathology. Regulation of immune responses can occur through a diverse range of mechanisms including bi-directional communication with neurons. Among which include specialized sensory neurons that detect noxious stimuli due to the expression of transient receptor potential vanilloid receptor 1 (TRPV1) ion channel and have a significant role in the coordination of host-protective responses to enteric bacterial pathogens. Here we have used the mouse-adapted attaching and effacing pathogen Citrobacter rodentium to assess the specific role of TRPV1 in coordinating the host response. TRPV1 knockout (TRPV1-/-) mice had a significantly higher C. rodentium burden in the distal colon and fecal pellets compared to wild-type (WT) mice. Increased bacterial burden was correlated with significantly increased colonic crypt hyperplasia and proliferating intestinal epithelial cells in TRPV1-/- mice compared to WT. Despite the increased C. rodentium burden and histopathology, the recruitment of colonic T cells producing IFNγ, IL-17, or IL-22 was similar between TRPV1-/- and WT mice. In evaluating the innate immune response, we identified that colonic neutrophil recruitment in C. rodentium infected TRPV1-/- mice was significantly reduced compared to WT mice; however, this was independent of neutrophil development and maturation within the bone marrow compartment. TRPV1-/- mice were found to have significantly decreased expression of the neutrophil-specific chemokine Cxcl6 and the adhesion molecules Icam1 in the distal colon compared to WT mice. Corroborating these findings, a significant reduction in ICAM-1 and VCAM-1, but not MAdCAM-1 protein on the surface of colonic blood endothelial cells from C. rodentium infected TRPV1-/- mice compared to WT was observed. These findings demonstrate the critical role of TRPV1 in regulating the host protective responses to enteric bacterial pathogens, and mucosal immune responses.

Impact of standardising indocyanine green fluorescence angiography technique for visual and quantitative interpretation on interuser variability in colorectal surgery.

Intra-operative colonic perfusion assessment via indocyanine green fluorescence angiography (ICGFA) aims to address malperfusion-related anastomotic complications; however, its interpretation suffers interuser variability (IUV), especially early in ICGFA experience. This work assesses the impact of a protocol developed for both operator-based judgement and computational development on interpretation consistency, focusing on senior surgeons yet to start using ICGFA. Experienced and junior gastrointestinal surgeons were invited to complete an ICGFA-experience questionnaire. They subsequently interpreted nine operative ICGFA videos regarding perfusion sufficiency of a surgically prepared distal colon during laparoscopic anterior resection by indicating their preferred site of proximal transection using an online annotation platform (mindstamp.com). Six ICGFA videos had been prepared with a clinical standardisation protocol controlling camera and patient positioning of which three each had monochrome near infrared (NIR) and overlay display. Three others were non-standardised controls with synchronous NIR and overlay picture-in-picture display. Differences in transection level between different cohorts were assessed for intraclass correlation coefficient (ICC) via ImageJ and IBM SPSS. 58 clinicians (12 ICGFA experts, 46 ICGFA inexperienced of whom 23 were either finished or within one year of finishing training and 23 were junior trainees) participated as per power calculations. 63% felt that ICGFA should be routinely deployed with 57% believing interpretative competence requires 11-50 cases. Transection level concordance was generally good (ICC = 0.869) across all videos and levels of expertise (0.833-0.915). However, poor agreement was evident with the standardised protocol videos for overlay presentation (0.208-0.345). Similarly, poor agreement was seen for the monochrome display (0.392-0.517), except for those who were trained but ICG inexperienced (0.877) although even here agreement was less than with unstandardised videos (0.943). Colorectal ICGFA acquisition and display standardisation impacts IUV with this specific protocol tending to diminish surgeon interpretation consistency. ICGFA video recording for computational development may require dedicated protocols.

Preclinical Ultra-High Dose Rate (FLASH) Proton Radiation Therapy System for Small Animal Studies

BackgroundAnimal studies with ultra-high dose-rate radiation therapy (FLASH, >40Gy/s) preferentially spare normal tissues without sacrificing anti-tumor efficacy compared to conventional dose-rate radiation therapy (CONV). At XXXX, we developed a cyclotron-generated preclinical scattered proton beam with FLASH dose rates. We present the technical details of our FLASH radiation system and preliminary biological results from whole pelvis radiation. MethodsA Scanditronix MC50 compact cyclotron beamline has been modified to produce a 48.7 MeV proton beam at dose rates between 0.1-150 Gy/s. The system produces a 6 cm diameter scattered proton beam (flat to +/-3%) at the target location. Female C57BL/6 mice 5-6 weeks old were used for all experiments. To study normal tissue effects in the distal colon, mice were irradiated using the entrance region of the proton beam to the whole pelvis, 18.5 Gy at different dose rates: control, CONV (0.6–1 Gy/s) and FLASH (50–80 Gy/s). Survival was monitored daily and EdU (5-ethynyl-2´-deoxyuridine) staining was performed at 24-hours and 96-hours post-radiation. Cleaved caspase-3 (C-CASP3) staining was performed 24-hours post-radiation. To study tumor control, allograft B16F10 tumors were implanted in the right flank and received 18 Gy CONV or FLASH proton radiation. Tumor growth and survival were monitored. ResultsAfter 18.5 Gy whole pelvis radiation, survival was 100% in the control group, 0% in the CONV group, and 44% in the FLASH group (p<0.01). EdU staining showed cell proliferation was significantly higher in the FLASH versus CONV group at both 24-hours and 96-hours post-radiation in the distal colon, although both radiation groups showed decreased proliferation compared to controls (P<0.05). Lower C-CASP3 staining was seen in the FLASH versus conventional group post-radiation (p<0.05). Comparable flank tumor control was observed in the CONV and FLASH groups. ConclusionWe present our preclinical FLASH proton radiation system and biological results showing improved survival after whole pelvis radiation, with equivalent tumor control.

The olfactory receptor Olfr78 promotes differentiation of enterochromaffin cells in the mouse colon

The gastrointestinal epithelium constitutes a chemosensory system for microbiota-derived metabolites such as short-chain fatty acids (SCFA). Here, we investigate the spatial distribution of Olfr78, one of the SCFA receptors, in the mouse intestine and study the transcriptome of colon enteroendocrine cells expressing Olfr78. The receptor is predominantly detected in the enterochromaffin and L subtypes in the proximal and distal colon, respectively. Using the Olfr78-GFP and VilCre/Olfr78flox transgenic mouse lines, we show that loss of epithelial Olfr78 results in impaired enterochromaffin cell differentiation, blocking cells in an undefined secretory lineage state. This is accompanied by a reduced defense response to bacteria in colon crypts and slight dysbiosis. Using organoid cultures, we further show that maintenance of enterochromaffin cells involves activation of the Olfr78 receptor via the SCFA ligand acetate. Taken together, our work provides evidence that Olfr78 contributes to colon homeostasis by promoting enterochromaffin cell differentiation.

Effect of beta-glucan supplementation on cystic fibrosis colonic microbiota: an in vitro study.

Children with cystic fibrosis (CF) present with gut dysbiosis, and current evidence impedes robust recommendations on the use of prebiotics. This study aimed at establishing the prebiotic potential of a commercial beta-glucan on the in vitro colonic microbiota of a child with CF compared to a healthy counterpart (H). A dynamic simulator of colonic fermentation (twin-SHIME® model) was set up including the simulation of the proximal (PC) and distal colon (DC) of the CF and the H subjects by colonizing the bioreactors with faecal microbiota. During two weeks the system was supplied with the beta-glucan. At baseline, during treatment and post-treatment, microbiota composition was profiled by 16 S rRNA and short-chain fatty acids (SCFA) production was determined by GS-MS. At baseline, Faecalibacterium, was higher in CF' DC than in the H, along higher Acidaminococcus and less Megasphaera and Sutterella. Beta-glucan supplementation induced increased microbiota richness and diversity in both subjects during the treatment. At genus level, Pseudomonas and Veillonella decreased, while Akkermansia and Faecalibacterium increased significantly in CF. The supplementation with beta-glucan suggests positive results on CF colonic microbiota in the in vitro context, encouraging further research in the in vivo setting. Current evidence supports assessing the effect of prebiotics on modifying cystic fibrosis microbiota. The effect of beta-glucan supplementation was evaluated in a controlled dynamic in vitro colonic ecosystem. Beta-glucan supplement improved diversity in cystic fibrosis colonic microbiota. The treatment showed increased abundance of Faecalibacterium and Akkermansia in cystic fibrosis. New evidence supports the use of prebiotics in future clinical studies.

Differential Myosin 5a splice variants in innervation of pelvic organs.

Introduction: Myosin proteins interact with filamentous actin and translate the chemical energy generated by ATP hydrolysis into a wide variety of mechanical functions in all cell types. The classic function of conventional myosins is mediation of muscle contraction, but myosins also participate in processes as diverse as exocytosis/endocytosis, membrane remodeling, and cytokinesis. Myosin 5a (Myo5a) is an unconventional motor protein well-suited to the processive transport of diverse molecular cargo within cells and interactions with multiprotein membrane complexes that facilitate exocytosis. Myo5a includes a region consisting of six small alternative exons which can undergo differential splicing. Neurons and skin melanocytes express characteristic splice variants of Myo5a, which are specialized for transport processes unique to those cell types. But less is known about the expression of Myo5a splice variants in other tissues, their cargos and interactive partners, and their regulation. Methods: In visceral organs, neurotransmission-induced contraction or relaxation of smooth muscle is mediated by Myo5a. Axons within urogenital organs and distal colon of rodents arise from cell bodies located in the major pelvic ganglion (MPG). However, in contrast to urogenital organs, the distal colon also contains soma of the enteric nervous system. Therefore, the rodent pelvic organs provide an opportunity to compare the expression of Myo5a splice variants, not only in different tissues innervated by the pelvic nerves, but also in different subcellular compartments of those nerves. This study examines the expression and distribution of Myo5a splice variants in the MPG, compared to the bladder, corpus cavernosum of the penis (CCP) and distal colon using immunohistochemistry and mRNA analyses. Results/discussion: We report detection of characteristic Myo5a variants in these tissues, with bladder and CCP displaying a similar variant pattern but one which differed from that of distal colon. In all three organs, Myo5a variants were distinct compared to the MPG, implying segregation of one variant within nerve soma and its exclusion from axons. The expression of distinct Myo5a variant arrays is likely to be adaptive, and to underlie specific functions fulfilled by Myo5a in those particular locations.

Endometriosis with colonic mucosal colonisation: a diagnostic confounder.

Secondary mucosal colonisation by a carcinoma originating from a distant site is a pattern of metastasis to the intestines and hepatobiliary tract and a mimic of primary neoplasia. Although endometriosis is considered benign, its ability to spread widely underscores its quasi-neoplastic nature. After noting that endometriotic glands can colonise the colonic mucosa along the basement membrane, mimicking metastatic disease, we conducted an intradepartmental review of intestinal specimens showing endometriosis obtained from 2016 to 2023 to characterise and quantify the incidence of this phenomenon. Material from 38 lower gastrointestinal specimens with a primary or ancillary diagnosis of endometriosis was identified from our surgical pathology database. Slides were reviewed, documenting the extent and micro-anatomic location affected by endometriosis, with a focus on identifying examples showing mucosal colonisation. The most common site of involvement was the distal colon (23 cases; 11 of rectum, 9 of sigmoid colon and 3 of rectosigmoid) followed by the appendix (N=10), cecum (N=2), small intestine (N=2) and 'colon not otherwise specified' (N=1). Mucosal involvement was identified in eight cases (21%), half of which demonstrated seamless colonisation of the epithelium by endometriotic glands. In two of these, the procedure was prompted by the presence of a rectal mass or stricture with concern for malignancy. Endometriosis occasionally (4/38; 10.5%) colonises colonic epithelium, potentially mimicking a metastasis or intraepithelial neoplasia/dysplasia. Although unusual, this phenomenon was observed in half of specimens from patients with mucosal involvement in whom a mass or stricture suggested malignancy, a potentially misleading pattern of endometriosis.

Effect of niclosamide on colorectal cancer induced by dimethylhydrazine in albino mice

ABSTRACTColorectal cancer (CRC) is a prevalent cancer worldwide, and its incidence has increased in recent years. 1,2-Dimethylhydrazine (DMH) is a carcinogenic alkylating agent that causes tumors in various organs, particularly the distal colon. Niclosamide (Nic) disrupts oxidative phosphorylation and lowers ATP levels in tumor cells. This study aimed to investigate the potential protective effects of Nic against DMH-induced CRC in male albino mice through histopathological, immunohistochemical, and biochemical analyses. The study involved subcutaneous injections of DMH at a dose of 15 μg/g administered twice weekly for six weeks, alone or in combination with Nic injections of 20 mg/kg twice weekly for six weeks. The colorectal paraffin slides were subjected to histopathology and apoptosis-inducing factor (AIF) immunostaining, and colorectal homogenate samples were used to measure the lipid peroxidation products malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG).The results indicated that Nic injections reduced collagen deposition and AIF staining intensity in paraffin slides and decreased MDA content and 8-OHdG levels in tissue homogenates.These findings suggest that Nic injections may have an anti-CRC effect.

Colon-targeted S100A8/A9-specific peptide systems ameliorate colitis and colitis-associated colorectal cancer in mouse models.

The link between chronic inflammation and cancer development is well acknowledged. Inflammatory bowel disease including ulcerative colitis and Crohn's disease frequently promotes colon cancer development. Thus, control of intestinal inflammation is a therapeutic strategy to prevent and manage colitis-associated colorectal cancer (CRC). Recently, gut mucosal damage-associated molecular patterns S100A8 and S100A9, acting via interactions with their pattern recognition receptors (PRRs), especially TLR4 and RAGE, have emerged as key players in the pathogenesis of colonic inflammation. We found elevated serum levels of S100A8 and S100A9 in both colitis and colitis-associated CRC mouse models along with significant increases in their binding with PRR, TLR4, and RAGE. In this study we developed a dual PRR-inhibiting peptide system (rCT-S100A8/A9) that consisted of TLR4- and RAGE-inhibiting motifs derived from S100A8 and S100A9, and conjugated with a CT peptide (TWYKIAFQRNRK) for colon-specific delivery. In human monocyte THP-1 and mouse BMDMs, S100A8/A9-derived peptide comprising TLR4- and RAGE-interacting motif (0.01, 0.1, 1 μM) dose-dependently inhibited the binding of S100 to TLR4 or RAGE, and effectively inhibited NLRP3 inflammasome activation. We demonstrated that rCT-S100A8/A9 had appropriate drug-like properties including in vitro stabilities and PK properties as well as pharmacological activities. In mouse models of DSS-induced acute and chronic colitis, injection of rCT-S100A8/A9 (50 μg·kg-1·d-1, i.p. for certain consecutive days) significantly increased the survival rates and alleviated the pathological injuries of the colon. In AOM/DSS-induced colitis-associated colorectal cancer (CAC) mouse model, injection of rCT-S100A8/A9 (50 μg·kg-1·d-1, i.p.) increased the body weight, decreased tumor burden in the distal colon, and significantly alleviated histological colonic damage. In mice bearing oxaliplatin-resistant CRC xenografts, injection of rCT-S100A8/A9 (20 μg/kg, i.p., every 3 days for 24-30 days) significantly inhibited the tumor growth with reduced EMT-associated markers in tumor tissues. Our results demonstrate that targeting the S100-PRR axis improves colonic inflammation and thus highlight this axis as a potential therapeutic target for colitis and CRC.

Aberrant Crypt Foci - Endpoint in Colorectal Cancer

Abstract Aberrant crypt foci (ACF) can be used as the endpoint in colorectal cancer development because aberrant crypts are postulated to be the earliest identifiable potential precursors of colorectal cancer. ACF were first described by Bird and defined as crypt that: (1) have altered luminal openings; (2) exhibit thickened epithelia; (3) are larger than adjacent normal crypts. ACF may eventually evolve into polyps and, subsequently, colorectal cancer in the case of adenoma-carcinoma sequence; it provides a simple and economical tool for preliminary screening of potential chemopreventive agents, and it allows a quantitative assessment of the mechanisms of colon carcinogenesis. ACF are morphological lesions that represent an early stage in the stepwise progression of colon cancer. These surface abnormalities often appear in the distal colon within 2 weeks of carcinogen treatment. Sequential analyses suggest that these early lesions increase in size and multiplicity and often exhibit nuclear atypia and dysplasia. ACF also shows increased proliferative activity, growth factor signaling and K-Ras mutations, suggesting that at least a subset of ACF are putative precursors of colon cancer. Human ACF shares a similar morphology and is present in grossly normal-appearing colon tissue from patients with colorectal cancer (CRC). It has been suggested that the nature and order of acquired genetic changes can profoundly impact ACF morphology and the likelihood of tumor progression. Although limited in numbers, flat dysplastic ACF appeared to be more likely to become tumors than the elevated ACF. Clearly, the expanding diversity of ACF identified in rodent carcinogen models provides researchers with exciting new tools for studying the earliest stages of CRC. Lesions characterized in these models may ultimately become useful for predicting cancer risk in humans.

New perspectives on the use of glucagon-like peptide 1 in diseases of the central nervous system

Abstract Glucagon-like peptide 1 is a neuromodulatory peptide that regulates the carbohydrate metabolism. It can cross the blood-brain barrier, and, indeed, while mostly produced in the distal small intestine and colon, it is also synthesized in the nucleus of the solitary tract of the brain stem. The wide distribution of glucagon-like peptide 1 receptors in the different areas of the brain is responsible for the pleiotropic effects of glucagon-like peptide 1 in the central nervous system. Notably, the peptide plays important roles in regulating food intake, in memory functioning, as well as in neuroprotective processes and emotions. This makes it an important tool in the treatment of many central nervous system related abnormalities, such as neurodegenerative diseases, addictions and neuropsychiatric disorders.

Malignant Transformation of Long-Standing Ileal Crohn's Disease Likely Favors Signet Ring Cell Adenocarcinoma Histology.

Signet ring cell adenocarcinomas (SRCCs) are a rare and aggressive histological subtype of adenocarcinomas typically with poor prognosis usually secondary to late stage at detection. In the small bowel, they constitute only 1% of all malignancies. In the last decade, there have been multiple case reports and small case series that have identified SRCCs, typically in the ileum, in patients with Crohn's disease. Crohn's disease is a transmural inflammatory condition that normally manifests in the distal ileum and colon, and is known to temporally increase the risk of malignancy. Given the profound rarity of SRCCs, establishing an association between Crohn's disease and SRCC is challenging. In this study, we performed a systematic review of case reports and small case series describing small bowel SRCCs in Crohn's disease patients. Most cases were found in the distal/terminal ileum, at a mean age of 59 years old. Virtually all tumors were locally advanced (pathological T stage 3 and 4), typically with at least N1 nodal disease. Two case studies (one is a case-control study and the other a cohort design) demonstrated that small bowel SRCC, as opposed to conventional adenocarcinoma, was significantly correlated to a history of Crohn's disease (35% vs. 0%, 73.5% vs. 28.5%), with a propensity to arise in the ileum (95% vs. 30%, 66.7% vs. 42.1%), and at earlier mean age (43 vs. 68 years, 53.7 vs. 61.7 years). We additionally used the Surveillance, Epidemiology, and End Results (SEER) database for insights into the clinicoepidemiological characteristics of ileum SRCCs. SRCCs composed 28.1% of all ileal SRCCs, compared to 11.0% for the adenocarcinomas, with a younger age at diagnosis (60.7 vs. 64.6 years), more distant disease at presentation (41.3% vs. 26.4%), and shorter overall median survival time (20 vs. 39 months). In summary, while there is limited direct evidence to support an association between small bowel SRCC and Crohn's disease, the phenomenon has been increasingly documented in the literature in the last decade. Clinicians treating Crohn's disease patients should consider this in their differential diagnosis, particularly when managing disease complications, as early detection and surgical intervention offer the best prognosis.

Intestinal FFA2 promotes obesity by altering food intake in Western diet-fed mice.

Short-chain fatty acids (SCFAs) are key nutrients that play a diverse set of roles in physiological function, including regulating metabolic homeostasis. Generated through the fermentation of dietary fibers in the distal colon by the gut microbiome, SCFAs and their effects are partially mediated by their cognate receptors, including free fatty acid receptor 2 (FFA2). FFA2 is highly expressed in the intestinal epithelial cells, where its putative functions are controversial, with numerous in vivo studies relying on global knockout mouse models to characterize intestine-specific roles of the receptor. Here, we used the Villin-Cre mouse line to generate a novel, intestine-specific knockout mouse model for FFA2 (Vil-FFA2) to investigate receptor function within the intestine. Because dietary changes are known to affect the composition of the gut microbiome, and can thereby alter SCFA production, we performed an obesogenic challenge on male Vil-FFA2 mice and their littermate controls (FFA2-floxed, FFA2fl/fl) to identify physiological changes on a high-fat, high-sugar 'Western diet' (WD) compared to a low-fat control diet (CD). We found that the WD-fed Vil-FFA2 mice were transiently protected from the obesogenic effects of the WD and had lower fat mass and improved glucose homeostasis compared to the WD-fed FFA2fl/fl control group during the first half of the study. Additionally, major differences in respiratory exchange ratio and energy expenditure were observed in the WD-fed Vil-FFA2 mice, and food intake was found to be significantly reduced at multiple points in the study. Taken together, this study uncovers a novel role of intestinal FFA2 in mediating the development of obesity.

Comparison of pathologies in patients operated for transverse colon tumor with embryogenic and anatomical insights

Aim: Transverse colon cancers account for only about 10% of all colon cancers. It is generally known that proximal and distal colon tumours have different genetic and biological features. he transverse colon serves as the division point between proximal and distal regions. In this study, transverse colon cancer was classified both embryologically and anatomically, and a comparative analysis was conducted based on pathological results. Method: A retrospective study was conducted on patients who underwent surgery for transverse colon cancer at Ankara Bilkent City Hospital between 2019 and 2023. Patients were classified embryologically as proximal and distal, and anatomically as hepatic angle, middle, and splenic angle, and pathological results were compared among these groups. Results: For embryogenic classification in terms of the final pathological staging, Group A had 1 (1.47%) in Stage 1, 32 (47.05%) in Stage 2, 26 (38.23%) in Stage 3, and 9 (13.23%) in Stage 4. Group B had 2 (2.54%) in Stage 1, 29 (50%) in Stage 2, 20 (34.48%) in Stage 3, and 7 (12.06%) in Stage 4. There was no significant difference between the groups. For anatomical classification , the number of patients in Stages 1, 2, 3, and 4 for Groups 1, 2, and 3 were as follows: Stage 1: 2 (3.5%), 1 (3.57%), 0 (0%); Stage 2: 29 (50.87%), 17 (60.81%), 15 (37.5%); Stage 3: 20 (35.7%), 7 (25%), 19 (47.5%); Stage 4: 7 (12.28%), 3 (10.71%), 6(15%).There was no statistically significant difference between the groups (p &gt; 0.05). Conclusion: The pathological results and stages of transverse colon cancers classified embryologically and anatomically showed no significant differences among the groups.

Intestinal Geographical Pattern of Gut Microbiome and Metabolites Identifies Novel Regulators of Graft-Versus-Host Disease

Introduction: The severity of T cell-mediated gastrointestinal graft-versus-host disease (GI-GVHD) correlates with a decrease in the gut microbiome diversity, loss of obligate anaerobic bacteria and alterations in levels of salutary metabolites like short chain fatty acids (SCFAs). However, it is unknown whether the intestinal anatomic geography of the microbiome and its metabolites impacts GI GVHD severity. Herein, we investigate the pattern of the gut microbiome and metabolites from four distinct anatomical sites of intestines after allogeneic stem cell transplant (allo-SCT) via shotgun metagenomics and untargeted mass-spectrometry. Methods: To determine the composition of the gut microbiome and gut metabolites of mice after allo-SCT, we utilized contemporaneous analyses of shotgun metagenomic sequencing and untargeted mass spectrometry on the gut contents of mice 7 or 21 days after major histocompatibility complex (MHC)-disparate BALB/c→C57BL/6 (B6) allogeneic SCT. We investigated the microbial community composition and gut metabolites from four distinct gut locations (terminal ileum, cecum, transverse colon, descending colon) and performed integrative analysis to assess for novel pathways that may regulate GVHD biology. For shotgun metagenomics analyses, reads were depth normalized with BBnorm v.38.96 and assembled per-sample with MEGAHIT v.1.2.9. Prodigal v.2.6.3 was used to find genes in each bin. KofamScan v.1.3.0 was used to assign KEGG ortholog IDs (KO) to translated genes predicted by Prodigal. Community composition profiles were produced with Kraken2 v.2.1.2 and Bracken v.2.6.1. Functional profiles for each sample were determined with the Kraken community composition profiles and Humann3 v.3.0.0, with a GTDB database built with Struo2. Results: Consistent with previous reports from direct stool analyses, our data demonstrated that after allo-SCT, gut microbial diversity is reduced, relative abundance of obligate anaerobes decreases, and relative abundance of facultative anaerobes increases at all the intestinal anatomic sites, but the difference was maximal in ileo-cecal contents. Furthermore, metabolomic analyses reveal a decrease in previously described metabolites such as, SCFAs, bile acids and indoles at these sites. The distinct patterns of change between control and allogeneic samples depended not only on the gut location probed but also correlated with timepoint after transplant (7 days or 21 days) highlighting the importance of probing different gut locations and timepoints. The largest driver of differences between sample groups was (1) gut location (2) time after transplant (3) transplant type. Integrative analyses demonstrated loss of microbial functional genes related to butyrate processing following allo-SCT complementing previous studies that demonstrated reduction in butyrate levels. Further bioinformatic analyses identified novel microbial functional genes and metabolites that may have biological implications. Analyses revealed that after allo-SCT, phenyllactic acid (PLA) levels increased in the transverse colon and distal colon (fig.1). PLA is an anti-microbial compound and has been shown to have immune modulatory properties. Administration of PLA in drinking water of mice after allo-SCT worsened GVHD severity and increased mortality indicating PLA may play a role in inducing dysbiosis and worsening GVHD severity. Conclusion: Contemporaneous analyses of shotgun metagenomic and untargeted mass spectrometry of gut contents after allo-SCT reveal changes in microbial composition and metabolites consistent with previous data from analyses from stool. However, our analysis demonstrates distinct patterns of key metabolites and microbes in between syngeneic and allogeneic depending on gut location and time after transplant. Furthermore, our analyses have identified novel functional genes and metabolites that are implicated in GVHD severity.

Effects of vincristine and monosodium glutamate on gastrointestinal motility and visceral sensitivity.

Chemotherapy-induced adverse effects are an unresolved nightmare. In preclinical studies in rats, the food additive monosodium glutamate (MSG) improved some of the side effects caused by cisplatin, but its effects in other models of chemotherapy-treated animals are not well known. The aim of this study was to test if MSG may improve some of the adverse effects induced by vincristine in rats. Young male Wistar rats were exposed or not to MSG (4 g L-1 ) in drinking water from week 0 till 1 week after treatment (week 3). Rats received two cycles of five daily intraperitoneal (ip) injections (Monday to Friday, weeks 1 and 2) of either saline (2 mL kg-1 ) or vincristine (0.1 mg kg-1 ). Gastrointestinal motility was measured invivo by radiological methods after the first and tenth ip administrations. On week 3, the threshold for mechanical somatic and colorectal sensitivity was recorded using Von Frey filaments applied to the paws and an intracolonic balloon, respectively. Finally, samples of the terminal ileum and distal colon were histologically evaluated in sections. Vincristine reduced body weight gain, food intake, and upper gastrointestinal transit, caused somatic (but not visceral) hypersensitivity and increased the thickness of the submucosal and muscle layers of the small intestine. In vincristine-treated animals, MSG partially prevented gastrointestinal dysmotility and reduced visceral sensitivity but did not improve structural alterations of the small intestine. MSG could be used as an adjuvant to conventional treatments to improve some gastrointestinal dysfunctions caused by chemotherapy.

Mice lacking γENaC palmitoylation sites maintain benzamil-sensitive Na+ transport despite reduced ENaC activity.

Epithelial Na+ channels (ENaCs) control extracellular fluid volume by facilitating Na+ absorption across transporting epithelia. In vitro studies showed that Cys-palmitoylation of the γ ENaC subunit is a major regulator of channel activity. We tested whether γ subunit palmitoylation sites are necessary for channel function in vivo by generating mice lacking the palmitoylated cysteines (γC33A,C41A) using CRISPR-Cas9 technology. ENaCs in dissected kidney tubules from γC33A,C41A mice had reduced open probability compared to wild type (WT) littermates maintained on either standard or Na+-deficient diets. Male mutant mice also had higher aldosterone levels than WT littermates following Na+ restriction. However, γC33A,C41A mice did not have reduced amiloride-sensitive Na+ currents in the distal colon or benzamil-induced natriuresis compared to WT mice. We identified a second, larger conductance cation channel in the distal nephron with biophysical properties distinct from ENaC. The activity of this channel was higher in Na+-restricted γC33A,C41A versus WT mice and was blocked by benzamil, providing a possible compensatory mechanism for reduced prototypic ENaC function. We conclude that γ subunit palmitoylation sites are required for prototypic ENaC activity in vivo, but are not necessary for amiloride/benzamil-sensitive Na+ transport in the distal nephron or colon.