Search Results (35)

Background: Necrotizing enterocolitis (NEC) is a life-threatening condition characterized by necrosis of the gastrointestinal tract caused by hypoperfusion and hypoxia-induced inflammation. Surgical treatment often requires resection, with high morbidity and mortality. Intestinal tissue engineering using absorbable biomaterials represents a potential alternative. Small intestinal submucosa (SIS) is a biodegradable extracellular matrix (ECM) scaffold that may facilitate regeneration of the native tissue. Objectives: The aim of our study is to investigate the regenerative potential of SIS in a rat model with multiple gastrointestinal defects. Methods: In rats, after a midline laparotomy, an approximately 1 cm full-thickness incision was performed on the anterior gastric wall, on the antimesenteric side of the small and large intestine, each covered with an SIS patch. After three weeks, the graft sites and adjacent fragments were harvested and fixed in 10% neutral buffered formalin. Cross-sections of the grafted area were processed and stained with hematoxylin and eosin for histologic analysis. Results: Among the fifteen Wistar rats used in the study, the survival rate was 80% (12/15). Macroscopic examination of the abdominal cavity after the second surgery showed no complications. Adhesions were present in 92% (11/12). Histological examination demonstrated complete mucosal coverage in all stomach samples, nine of the small intestine, and ten of the large intestine. Mild fibrosis with minimal inflammatory infiltrates predominated. Ulceration with granulation tissue replacement was observed in three small intestine samples. Foreign body reactions were restricted to suture sites. Conclusions: In this multifocal injury model, SIS integrated effectively and supported early regenerative healing across gastric, small-intestinal, and colonic sites at 3 weeks. These data support further studies with longer follow-up, quantitative histology and functional assessment, and evaluation in neonatal-relevant large animal models to determine translational potential for NEC surgery. Full article

Background: Congenital diarrhea is persistent diarrhea that manifests during the neonatal period. Mutations in DGAT1, which is crucial for triglyceride synthesis and lipid absorption in the small intestine, are causal factors for congenital diarrhea. In this study, we aimed to determine the value of tissue RNA sequencing (RNA-seq) for assisting with the clinical diagnosis of some genetic variants of uncertain significance. Methods: We clinically evaluated a patient with watery diarrhea, vomiting, severe malnutrition, and total parenteral nutrition dependence. Possible pathogenic variants were detected using whole-exome sequencing (WES). RNA-seq was utilized to explore the transcriptional alterations in DGAT1 variants identified by WES with unknown clinical significance, according to the American College of Medical Genetics guidelines. Systemic examinations, including endoscopic and histopathological examinations of the intestinal mucosa, were conducted to rule out other potential diagnoses. Results: We successfully diagnosed a patient with congenital diarrhea and protein-losing enteropathy caused by a DGAT1 mutation and reviewed the literature of 19 cases of children with DGAT defects. The missense mutation c.620A>G, p.Lys207Arg located in exon 15, and the intronic mutation c.1249-6T>G in DGAT1 were identified by WES. RNA-seq revealed two aberrant splicing events in the DGAT1 gene of the patient’s small intestinal tissue. Both variants lead to loss-of-function consequences and are classified as pathogenic variants of congenital diarrhea. Conclusions: Rare DGAT1 variants were identified as pathogenic evidence of congenital diarrhea, and the detection of tissue-specific mRNA splicing and transcriptional effects can provide auxiliary evidence. Full article

Inflammatory Bowel Disease (IBD) is a group of chronic and recurrent inflammatory diseases characterized by prolonged inflammation of the intestinal tract. Although it has been proven that the immune system plays a crucial role in the pathogenesis of IBD, a defective intestinal epithelium is also responsible for chronic inflammation, hence causing an over-activation of the immune response. For this reason, a therapeutic approach that acts by improving impaired intestinal homeostasis could ensure a greater therapeutic efficacy in IBD. Mitogen-activated protein kinases (MAPKs) signaling pathways may be involved in the pathogenesis of IBD. It has been demonstrated that the inhibition of mitogen-activated protein kinase kinase 1 (MEK1) may be a potential treatment against IBD since it may restore the normal epithelial function and reduce apoptosis of intestinal epithelial cells (IECs). New therapeutic strategies are emerging including small molecules such as microRNAs (miRNAs). In this study, we aimed to demonstrate that miR-369-3p was able to modulate the MEK/ERK signaling pathway. As reported by in silico analysis, miR-369-3p was capable of pairing the 3’UTR of the MAP2K1 gene. In vitro analysis demonstrated that mimic transfection with miR-369-3p in epithelial cells downregulated the expression of MEK1, reduced the activation of ERK signaling, and modulated apoptosis of epithelial cells in response to TNF-α. Moreover, miR-369-3p significantly decreased the release of pro-inflammatory cytokine IL-8. These results support the potential of miR-369-3p to prevent apoptosis of IECs, responsible for a persistent inflammatory condition in IBD, highlighting its application value in the treatment of inflammatory disorders. Full article

Irritable bowel syndrome (IBS) is a gut–brain interaction disorder often associated with food-related triggers, yet the efficacy of common exclusion diets remains debated. Confocal laser endomicroscopy (CLE) offers real-time, high-resolution imaging of intestinal mucosal changes, allowing the visualization of food-induced barrier dysfunction. Early evidence indicates that a substantial subset of IBS patients exhibit acute mucosal reactions to specific foods, identified as fluorescein leakage and cell shedding on CLE, with over 70% showing symptom improvements after tailored exclusion diets. These findings suggest that localized immune responses and barrier defects may contribute to IBS symptoms beyond IgE-driven immunologic mechanisms. However, most CLE-based studies are small, unblinded, and heterogeneous, limiting definitive conclusions. Further research is needed to validate the diagnostic accuracy of CLE, refine protocols, and clarify how best to integrate CLE into personalized dietary management for difficult-to-treat IBS. Full article

Short bowel syndrome (SBS), usually resulting from massive small bowel resections or congenital defects, may lead to intestinal failure (IF), requiring intravenous fluids and parenteral nutrition to preserve patients’ nutritional status. Approximately 15% to 40% of subjects with SBS and IF develop chronic hepatic damage during their life, a condition referred to as intestinal-failure-associated liver disease (IFALD), which ranges from steatosis to fibrosis or end-stage liver disease. Parenteral nutrition has been largely pointed out as the main pathogenetic factor for IFALD. However, other elements, such as inflammation, bile acid metabolism, bacterial overgrowth and gut dysbiosis also contribute to the development of liver damage and may deserve specific treatment strategies. Indeed, in our review, we aim to explore IFALD pathogenesis beyond parenteral nutrition. By critically analyzing recent literature, we seek to delve with molecular mechanisms and metabolic pathways underlying liver damage in such a complex set of patients. Full article

The host response to S. Typhimurium infection can be post-transcriptionally regulated by miRNAs. In this study, we investigated the role of miR-215 using both in vivo porcine infection models and in vitro intestinal epithelial cell lines. Several miRNAs were found to be dysregulated in the porcine ileum during infection with wild-type and SPI2-defective mutant strains of S. Typhimurium, with some changes being SPI2-dependent. Notably, miR-215 was significantly downregulated during infection. To explore its functional role, gain-of-function experiments were performed by transfecting porcine intestinal epithelial cells (IPEC-J2) with a miR-215-5p mimic, followed by label-free quantitative (LFQ) proteomic analysis. This analysis identified 157 proteins, of which 35 were downregulated in response to miR-215 overexpression, suggesting they are potential targets of this miRNA. Among these, E2 small ubiquitin-like modifier (SUMO)-conjugating enzyme UBC9 and E3 ubiquitin-ligase HUWE1 were identified as key targets, both of which are upregulated during S. Typhimurium infection. The miR-215-mediated downregulation of these proteins resulted in a significant decrease in overall ubiquitination, a process crucial for regulating inflammasome activation and autophagy. Consistently, inflammasome markers caspase 1 (CASP1) and apoptosis-associated speck-like protein containing a CARD (ASC), as well as autophagy markers microtubule-associated protein 1A/1B-light chain 3 (LC3B) and Ras-related protein Rab-11 (RAB11A), showed decreased expression in miR-215 mimic-transfected and infected IPEC-J2 cells. To further validate these findings, human intestinal epithelial cells (HT29) were used as a complementary model, providing additional insights into conserved immune pathways and extending the observations made in the porcine system. Overall, our findings demonstrate that miR-215 plays a significant role in modulating host inflammasome activation and autophagy by targeting proteins involved in ubiquitination during S. Typhimurium infection. Full article

Organoid technology, as an innovative approach in biomedicine, exhibits promising prospects in disease modeling, pharmaceutical screening, regenerative medicine, and oncology research. However, the use of tumor-derived Matrigel as the primary method for culturing organoids has significantly impeded the clinical translation of organoid technology due to concerns about potential risks, batch-to-batch instability, and high costs. To address these challenges, this study innovatively introduced a photo-crosslinkable hydrogel made from a porcine small intestinal submucosa decellularized matrix (SIS), fish collagen (FC), and methacrylate gelatin (GelMA). The cost-effective hydrogel demonstrated excellent biocompatibility, tunable mechanical properties, rapid gelation properties, and low immunogenicity. Importantly, the proliferation and differentiation capacities of small intestinal organoids cultured in hydrogel were comparable to those in Matrigel, with no significant disparity observed. Furthermore, after one week of transplantation in nude mice, the hydrogel–organoid complex exhibited sustained structural and functional stability while preserving the differentiation characteristics of small intestinal organoids. Our study also demonstrated the effective potential of FC/SIS/GelMA hydrogel in accelerating the repair process of small intestinal defects, reducing the area of scar formation, and promoting the regeneration of both intestinal villi and smooth muscle tissue. In summary, this study presents a novel protocol for culturing small intestinal organoids, offering potential implications for future clinical applications and serving as an experimental foundation for the development of tissue-engineered intestines based on small intestinal organoids. Full article

Bile salts possess innate antibacterial properties and can cause significant damage to bacteria. To survive in the mammalian gut, Klebsiella pneumoniae has developed mechanisms to tolerate bile salts; however, the specific mechanisms remain unclear. Transposon library screening revealed that the efflux pump AcrAB is involved in bile salt resistance. acrA and acrB mutants exhibited high sensitivity not only to bile salts but also to SDS and various antibiotics, with a switch-loop, comprising residues G615, F616, A617, and G618, proving to be crucial in this process. A colonization defect of acrA and acrB mutants was demonstrated to be located in the mouse small intestine, where the bile salt concentration is higher compared to the large intestine. Additionally, both acrA and acrB mutants displayed reduced virulence in the Galleria mellonella model. In conclusion, our results suggest that the Resistance-Nodulation-Cell Division efflux pump serves as a critical determinant in the pathogenesis of K. pneumoniae through various aspects. Full article

Background: Celiac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten, affecting approximately 1% of the global population and two million Americans. An increasing number of studies have identified a link between celiac disease and adverse maternal and fetal outcomes during pregnancy and after birth. Additionally, both celiac disease and pregnancy are associated with an increased risk for nutrient deficiencies, specifically vitamin B12 and folate. Methods: This review examines the current literature related to the folate trap and vitamin B12 deficiency in patients with celiac disease and pregnant women independently and provides rationale for future research to explore the relationship between the folate-to-12 ratio in pregnant women with celiac disease. Results: Deficiencies in vitamin B12 are linked with several negative maternal and fetal health outcomes including pre-eclampsia, gestational diabetes, spontaneous abortion/miscarriage, preterm birth, neural tube defects, intrauterine growth restriction, and low gestational age and birthweight. Conclusions: Folic acid supplementation is widely recommended during pregnancy, but complementary vitamin B12 supplementation is not standard. Physicians should consider celiac disease screening during pregnancy as well as vitamin B12 supplementation. Full article

Background: Chronic liver disease occurs throughout the world irrespective of region, age, sex, or race, and it is caused by a variety of liver conditions. One of the most frequent infectious complications in liver cirrhosis that severely reduces the median survival is spontaneous bacterial peritonitis. Current guidelines recommend a paracentesis before starting an antibiotic prophylaxis for this complication. Methods: Selective intestinal decontamination significantly lowers the rate of first or recurrent SBP in cirrhotic patients, so in this study we aimed to investigate and quantify the intestinal integrity of patients with liver cirrhosis and correlate a pathologically increased permeability with the incidence of SPB. We included 14 patients who met the inclusion criteria. No patient was excluded. For the CLE investigation, we use probe based confocal laser endomicroscopy techniques from Mauna Kea (Cellvizio), enabling in vivo surface imaging. The images (optical biopsies) were analyzed for functional and structural barrier defects after the procedure using Mauna Kea software (version 1.0.09). Results: Because of the small number of included patients and healthy controls, most results are lacking statistical relevance. We found that the CLE investigation showed an increased intestinal permeability in patients with liver cirrhosis, in concordance with previous published data, based on other assessment methods. Conclusions: This study confirms that previously published permeability scores can be applied for patients with liver cirrhosis and is, to our knowledge, the first to investigate the intestinal permeability in vivo in patients with liver cirrhosis. Further data are needed to identify patients at risk and help develop new and less invasive diagnostic criteria for cirrhotic patients who may profit from a prophylactic antibiotic treatment. Full article

Background and Objectives: Spontaneous colonic perforations (SCPs) in teenagers and young adults are extremely rare. Common underlying conditions, such as colonic tumors and diverticulitis, are absent at that age. The vascular type of Ehlers–Danlos Syndrome (vEDS) is one cause of SCP. Methods: A 23-year-old male presented with an acute abdomen. The abdominal CT showed pneumoperitoneum with a large amount of fluid in the pelvis and abdomen, indicating hollow viscus rupture. At the level of the sigmoid colon, a defect in the intestinal wall and gas bubbles were seen. Results: Exploratory laparotomy confirmed sigmoid colon perforation without underlying pathology. Loop sigmoid colostomy was performed. Revisional surgery was undertaken due to clinical deterioration and intra-abdominal free fluid with small-bowel distension and air-liquid levels on abdominal CT 6 days later. Ileal subserosal hematomas were found, and many had ruptured, leaving a “zebra” pattern with lines of residual hematomas on the borders of subserosal hematomas. Genetic analysis confirmed vEDS. Conclusions: SCP in young adults or teenagers, in the absence of colonic disease, with clinical manifestations of connective tissue disorders should trigger genetic investigations for vEDS. SCP with a known vEDS could be treated with total colectomy to prevent further SCPs in the remaining colon. If segmental resections are performed, further SCP should be immediately excluded with any significant abdominal pain. Full article

Enteroendocrine cells (EECs) constitute only a small proportion of Villin-1 (Vil1)-expressing intestinal epithelial cells (IECs) of the gastrointestinal tract; yet, in sum, they build the largest endocrine organ of the body, with each of them storing and releasing a distinct set of peptides for the control of feeding behavior, glucose metabolism, and gastrointestinal motility. Like all IEC types, EECs are continuously renewed from intestinal stem cells in the crypt base and terminally differentiate into mature subtypes while moving up the crypt–villus axis. Interestingly, EECs adjust their hormonal secretion according to their migration state as EECs receive altering differentiation signals along the crypt–villus axis and thus undergo functional readaptation. Cell-specific targeting of mature EEC subtypes by specific promoters is challenging because the expression of EEC-derived peptides and their precursors is not limited to EECs but are also found in other organs, such as the brain (e.g., Cck and Sst) as well as in the pancreas (e.g., Sst and Gcg). Here, we describe an intersectional genetic approach that enables cell type-specific targeting of functionally distinct EEC subtypes by combining a newly generated Dre-recombinase expressing mouse line (Vil1-2A-DD-Dre) with multiple existing Cre-recombinase mice and mouse strains with rox and loxP sites flanked stop cassettes for transgene expression. We found that transgene expression in triple-transgenic mice is highly specific in I but not D and L cells in the terminal villi of the small intestine. The targeting of EECs only in terminal villi is due to the integration of a defective 2A separating peptide that, combined with low EEC intrinsic Vil1 expression, restricts our Vil1-2A-DD-Dre mouse line and the intersectional genetic approach described here only applicable for the investigation of mature EEC subpopulations. Full article

Background: The over-the-scope clip (OTSC) is a highly effective clipping device for refractory gastrointestinal disease. However, Japanese data from multicenter studies for anastomotic leakage (AL) involving a secondary fistula after gastrointestinal surgery are lacking. Therefore, this study evaluated the efficacy and safety of OTSC placement in Japanese patients with such conditions. Methods: We retrospectively collected data from 28 consecutive patients from five institutions who underwent OTSC-mediated closure for AL between July 2017 and July 2020. Results: The AL and fistula were located in the esophagus (3.6%, n = 1), stomach (10.7%, n = 3), small intestine (7.1%, n = 2), colon (25.0%, n = 7), and rectum (53.6%, n = 15). The technical success, clinical success, and complication rates were 92.9% (26/28), 71.4% (20/28), and 0% (0/28), respectively. An age of <65 years (85.7%), small intestinal AL (100%) and colonic AL (100%), defect size of <10 mm (82.4%), time to OTSC placement > 7 days (84.2%), and the use of simple suction (78.9%) and anchor forceps (80.0%) were associated with higher clinical success rates. Conclusion: OTSC placement is a useful therapeutic option for AL after gastrointestinal surgery. Full article

Dysbiosis of the gut microbiota is associated with the pathogenesis of intestinal diseases such as inflammatory bowel disease, irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), and metabolic disease states such as allergies, cardiovascular diseases, obesity, and diabetes. SIBO is a condition characterized by an increased number (>1 × 10³ CFU) of abnormal bacterial species in the small intestine. Interest in SIBO has gained importance due to increased awareness of the human microbiome and its potential relationships with human health and disease, which has encouraged new work in this area. In recent years, standard antibiotic regimens (rifaximin and metronidazole) have been used to treat SIBO, but solo antibiotics or their derivatives are insufficient. In this study, the therapeutic effects of the probiotic form, which contains coconut oil and traces of peppermint-lemon-patchouli essential oil, were evaluated on the Dysbiosis-Based Rat SIBO Model. There are significant differences between sick and healthy rats (p = 0.014), between sick rats and rats treated with the oil mix plus probiotic mix protocol (p = 0.026), and between rats treated with only the probiotic and only oil protocols (p = 0.030) in the evaluation of TNF-α levels. Histologically, villi distortion and loss of crypts, epithelial shedding and necrotic changes in the apical regions of the villi, and inflammatory cell infiltrations extending to the lamina propria and submucosa were observed in sick rats. Mitotic figures in villus epithelium and crypts were observed in rats treated with 9.2 × 10⁹ CFU/1000 mg/coconut oil + trace amounts of peppermint-lemon-patchouli essential oil and a probiotic mixture (oil + probiotic mix protocol). A regression of inflammatory reactions and an increase in goblet cells were observed. A decrease was observed in inflammation markers in sick rats. On the other hand, the oil plus probiotic mix protocol recovered digestive system defects in the animals caused by dysbiosis. In the future, these treatment approaches can be effective in the treatment of SIBO. Full article

Background: Tropheryma whipplei (TW) can cause different pathologies, e.g., Whipple’s disease and transient gastroenteritis. The mechanism by which the bacteria pass the intestinal epithelial barrier, and the mechanism of TW-induced gastroenteritis are currently unknown. Methods: Using ex vivo disease models comprising human duodenal mucosa exposed to TW in Ussing chambers, various intestinal epithelial cell (IEC) cultures exposed to TW and a macrophage/IEC coculture model served to characterize endocytic uptake mechanisms and barrier function. Results: TW exposed ex vivo to human small intestinal mucosae is capable of autonomously entering IECs, thereby invading the mucosa. Using dominant-negative mutants, TW uptake was shown to be dynamin- and caveolin-dependent but independent of clathrin-mediated endocytosis. Complementary inhibitor experiments suggested a role for the activation of the Ras/Rac1 pathway and actin polymerization. TW-invaded IECs underwent apoptosis, thereby causing an epithelial barrier defect, and were subsequently subject to phagocytosis by macrophages. Conclusions: TW enters epithelia via an actin-, dynamin-, caveolin-, and Ras-Rac1-dependent endocytosis mechanism and consecutively causes IEC apoptosis primarily in IECs invaded by multiple TW bacteria. This results in a barrier leak. Moreover, we propose that TW-packed IECs can be subject to phagocytic uptake by macrophages, thereby opening a potential entry point of TW into intestinal macrophages. Full article