Crypt Epithelium Research Articles

Evaluation of inhibitory potential of the flavonoid-rich fraction of Myrica esculenta Buch.-Ham. ex D. Don against DSS-induced colonic inflammation in mice

ObjectiveMyrica esculenta (family Myricaceae), a valuable plant species in China and India, has been traditionally used by many tribes and local communities to manage gut disorders. Scientific validation of its anti-ulcerative colitis activity was aimed. MethodsThe ethyl acetate fraction of Myrica esculenta (MeEa) was prepared and evaluated for its potency against DSS-induced ulcerative colitis (UC) in mice at 200 and 400 mg/kg BW oral dose. The effective dose of MeEa was determined through its effect on DSS-induced UC and was further analyzed through its effects on disease activity index (DAI), colon length, colon weight/length ratio, spleen weight, serum and colon tissue cytokine level, cell count and hemoglobin content. Further, the effect was determined through histopathology and FITC-dextran-induced membrane permeability assay. ResultsBetween the two doses, MeEa at 400 mg/kg BW was found to be the most effective dose in terms of reduced DAI scores, protected colon length from shortening, decreased colon weight/length ratio, reduced spleen weight, decreased pro-inflammatory cytokine level and stabilized the anti-inflammatory cytokine level in serum and colon tissue. MeEa 400 reduced cell counts and increased hemoglobin content and platelet count. MeEa 400 also prevented the colon by protecting epithelial cells and crypts. MeEa 400 provided significant protection from intestinal leakage and reduced FITC dextran level in serum. DiscussionMeEa 400 possesses significant anti-inflammatory potential and acts via attenuation of DSS-induced UC and inhibition of DAI scores. It reduces pro-inflammatory cytokines and stabilizes anti-inflammatory cytokine levels, reduces cell count, and protects epithelial tissue and crypts in the colon, as well as intestinal membrane leakage that occurred due to FITC-dextran administration in mice.

Regulatory effects of the p38 mitogen-activated protein kinase-myosin light chain kinase pathway on the intestinal epithelial mechanical barrier and the mechanism of modified Pulsatilla decoction in the treatment of ulcerative colitis.

To investigate the mechanism of the protective effect of modified Pulsatilla decoction (, MPD) on the mechanical barrier of the ulcerative colitis (UC) intestinal epithelium in vitro and in vivo. We established an intestinal epithelial crypt cell line-6 cell barrier injury model by using lipopolysaccharide (LPS). The model was then treated with p38 mitogen-activated protein kinase-myosin light chain kinase (p38MAPK-MLCK) pathway inhibitors, p38MAPK-MLCK pathway silencing genes (si-p38MAPK, si-NF-κB, and si-MLCK), and MPD respectively. Transepithelial electronic resistance (TEER) measurements and permeability assays were performed to assess barrier function. Immunofluorescence staining of tight junctions (TJ) was performed. In in vivo experiment, dextran sodium sulfate-induced colitis rat model was conducted to evaluate the effect of MPD and mesalazine on UC. The rats were scored using the disease activity index based on their clinical symptoms. Transmission electron microscopy and hematoxylin-eosin staining were used to examine morphological changes in UC rats. Western blotting and real-time quantitative polymerase chain reaction were performed to examine the gene and protein expression of significant differential molecules. In in vitro study, LPS-induced intestinal barrier dysfunction was inhibited by p38MAPK-MLCK pathway inhibitors and p38MAPK-MLCK pathway gene silencing. Silencing of p38MAPK-MLCK pathway genes decreased TJ expression. MPD treatment partly restored the LPS-induced decreased in TEER and increase in permeability. MPD increased the gene and protein expression of TJ, while down-regulated the LPS-induced high expression of p-p38MAPK and p-MLC. In UC model rats, MPD could ameliorate body weight loss and disease activity index, relieve colonic pathology, up-regulate TJ expression as well as decrease the expression of p-p38MAPK and p-MLC in UC rat colonic mucosal tissue. The p38MAPK-MLCK signaling pathway can affect mechanical barrier function and TJ expression in the intestinal epithelium. MPD restores TJ expression and attenuates intestinal epithelial barrier damage by suppressing the p38MAPK-MLCK pathway.

Urolithin A attenuates hexavalent chromium-induced small intestinal injury by modulating PP2A/Hippo/YAP1 pathway

Hexavalent chromium (Cr(VI)) exposure has been linked with gastrointestinal toxicity, whereas the molecular pathways and key targets remain elusive. Computational toxicology analysis predicted the correlation between protein phosphatase 2A (PP2A) and genes regarding Cr(VI)-induced intestinal injury. Here, we generated a mouse model with intestinal epithelium-specific knock out of Ppp2r1a (encoding PP2A Aα subunit) to investigate the mechanisms underlying Cr(VI)-induced small intestinal toxicity. Heterozygous (HE) mice and matched WT littermates were administrated with Cr(VI) at 0, 5, 20, and 80mg/l for 28 successive days. Cr(VI) treatment led to crypt hyperplasia, epithelial cell apoptosis, and intestinal barrier dysfunction, accompanied by the decline of goblet cell counts and Occludin expression in WT mice. Notably, these effects were aggravated in HE mice, indicating that PP2A Aα deficiency conferred mice with susceptibility to Cr(VI)-induced intestinal injury. The combination of data analysis and biological experiments revealed Cr(VI) exposure could decrease YAP1 phosphorylation at Ser127 but increase protein expression and activity, together with elevated transcriptional coactivator with PDZ-binding motif protein driving epithelial crypt cells proliferation following damage, suggesting the involvement of Hippo/YAP1 signaling pathway in Cr(VI)-induced intestinal toxicity. Nevertheless, the enhanced phosphorylation of YAP1 in HE mice resulted in proliferation/repair defects in intestinal epithelium, thereby exacerbating Cr(VI)-induced gut barrier dysfunction. Notably, by molecular docking and further studies, we identified urolithin A, a microbial metabolite, attenuated Cr(VI)-induced disruption of intestinal barrier function, partly by modulating YAP1 expression and activity. Our findings reveal the novel molecular pathways participated in Cr(VI)-caused small intestinal injury and urolithin A could potentially protect against environmental hazards-induced intestinal diseases.

Endogenous Hyaluronan Promotes Intestinal Homeostasis and Protects against Murine Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is a complex, multifactorial gastrointestinal disorder predominantly affecting preterm infants. The pathogenesis of this condition involves a complex interplay between intestinal barrier dysfunction, microbial dysbiosis, and an altered immune response. This study investigates the potential role of endogenous hyaluronan (HA) in both the early phases of intestinal development and in the context of NEC-like intestinal injury. We treated neonatal CD-1 mouse pups with PEP1, a peptide inhibiting HA receptor interactions, from postnatal days 8 to 12. We evaluated postnatal intestinal developmental indicators, such as villi length, crypt depth, epithelial cell proliferation, crypt fission, and differentiation of goblet and Paneth cells, in PEP1-treated animals compared with those treated with scrambled peptide. PEP1 treatment significantly impaired intestinal development, as evidenced by reductions in villi length, crypt depth, and epithelial cell proliferation, along with a decrease in crypt fission activity. These deficits in PEP1-treated animals correlated with increased susceptibility to NEC-like injuries, including higher mortality rates, and worsened histological intestinal injury. These findings highlight the role of endogenous HA in supporting intestinal development and protecting against NEC.

Pathology of coccidiosis in budgerigars (Melopsittacus undulatus)

The present study was carried out to describe the occurrence and pathological findings in infections with Eimeria spp. in budgerigars. Postmortem examination was conducted on the carcasses of 32 Budgerigars received from various pet shops, pet bird breeders and pet bird owners of Puducherry. The budgerigars were of either sex and their age ranged from 1 to 5 years. The reported clinical signs were anorexia, lethargy, loss of body weight and diarrhoea. Coccidiosis was diagnosed in 46.87 % (15/32) of the cases. Gross features were localized in the small intestine and included serosal congestion, catarrhal, haemorrhagic and necrotic enteritis. The intestinal scraping revealed oocysts of Eimeria spp. Histological examination of various portions of the small intestines revealed catarrhal, haemorrhagic or necrotising enteritis and the developmental stages of Eimeria spp. in the intestinal and the crypt epithelium and also in the lumen of the intestine. Other changes were crypt cell proliferation and mononuclear cell infiltration.

Construction and validation of a rat model of acute necrotizing pancreatitis-associated intestinal injury.

Acute pancreatitis (AP) is an acute inflammatory reaction of the pancreatic tissue, which involves auto-digestion, edema, hemorrhage, and necrosis. AP can be categorized into mild, moderately severe, and severe AP, with severe pancreatitis also referred to as acute necrotizing pancreatitis (ANP). ANP is characterized by the accumulation of necrotic material in the peritoneal cavity. This can result in intestinal injury. However, the mechanism of ANP-associated intestinal injury remains unclear. We established an ANP-associated intestinal injury rat model (ANP-IR model) by injecting pancreatitis-associated ascites fluid (PAAF) and necrotic pancreatic tissue at various proportions into the triangular area formed by the left renal artery and ureter. The feasibility of the ANP-IR model was verified by comparing the similar changes in indicators of intestinal inflammation and barrier function between the two rat models. In addition, we detected changes in apoptosis levels and YAP protein expression in the ileal tissues of rats in each group and validated them in vitro in rat epithelial crypt cells (IEC-6) to further explore the potential injury mechanisms of ANP-associated intestinal injury. We also collected clinical data from patients with ANP to validate the effects of PAAF and pancreatic necrosis on intestinal injury. Our findings offer a theoretical basis for restricting the buildup of peritoneal necrosis in individuals with ANP, thus promoting the restoration of intestinal function and enhancing treatment efficacy. The use of the ANP-IR model in further studies can help us better understand the mechanism and treatment of ANP-associated intestinal injury.NEW & NOTEWORTHY We constructed a rat model of acute necrotizing pancreatitis-associated intestinal injury and verified its feasibility. In addition, we identified the mechanism by which necrotic pancreatic tissue and pancreatitis-associated ascites fluid (PAAF) cause intestinal injury through the HIPPO signaling pathway.

Anti-Inflammatory Effects of Zinc Oxide and Berberine in Rats with Dextran Sulfate Sodium (DSS)-Induced Colitis.

Zinc oxide (ZnO) is frequently used in high concentrations to prevent diarrhea in weaning pigs. However, it can produce environmental pollution, because it is not absorbed by the intestines and is excreted in the feces. In studies to identify an alternative substance to ZnO, we used a model of colitis induced by dextran sulfate sodium (DSS) in rats to compare the anti-inflammatory effects of berberine with ZnO. DSS-treated rats displayed weight loss, shortening of the colon, increased fecal water content, and an increase in the disease activity index (DAI). In contrast, DSS + ZnO- and DSS + berberine-treated rats exhibited reduced colon shortening, decreased fecal water content, and a decrease in the DAI. Histological analysis revealed that both ZnO and berberine treatment reduced epithelial cell damage, crypt destruction, and infiltration of inflammatory cells. Moreover, the liver damage index was not significantly different between ZnO and berberine-treated rats. This study indicated that both ZnO and berberine can improve DSS-induced colitis in rats and suggests berberine as an alternative treatment to ZnO that would not cause environmental pollution.

Fermentation of Luffa cylindrica by Lactiplantibacillus plantarum P101 enhanced functional properties: Insights into immune modulation, intestinal barrier repair, and intestinal microbiota regulation

Luffa cylindrica is a multifunctional plant resource with excellent but little-known functional properties, limited by its low processing and utilization rates. The emerging probiotic fermentation processing is an efficient and convenient way to improve the utilization rate of fruits and vegetables. To investigate the impact of probiotic fermentation on the functional properties of Luffa cylindrica, we fermented Luffa cylindrica with Lactiplantibacillus plantarum P101 and compared the intervention effects of Luffa cylindrica juice (LJ) and Luffa cylindrica fermentation broth (LF) on the damage caused by cyclophosphamide (CTX). After 14 days of intervention with LJ or LF, we collected samples from the thymus, spleen, blood, ileum, and cecum contents from BALB/C mice for subsequent analysis. The results indicate that LF provides better relief from CTX-induced damage than LJ. The main adverse effects caused by immune dysregulation, thymic atrophy, decreased blood leukocyte (WBC) count, and intestinal cytokine levels, were further improved by LF intervention. In addition, under the intervention of LF, intestinal epithelial cells and crypts were further protected, and their tight junction protein expression and mucus secretion were also promoted. Intestinal microbial dysbiosis, positively correlated with intestinal barrier disruption and immunosuppression, was also further alleviated by LF intervention. In summary, fermentation significantly enhanced immune modulation, intestinal barrier repair, and intestinal microbiota regulation of Luffa cylindrica. The results of our study may help people realize the little-known valuable functional properties of Luffa cylindrica, and may be expected to expand the types of functional foods.

A mechanistic modelling approach of the host-microbiota interactions to investigate beneficial symbiotic resilience in the human gut.

The health and well-being of a host are deeply influenced by the interactions with its gut microbiota. Contrasted environmental conditions, such as diseases or dietary habits, play a pivotal role in modulating these interactions, impacting microbiota composition and functionality. Such conditions can also lead to transitions from beneficial to detrimental symbiosis, viewed as alternative stable states of the host-microbiota dialogue. This article introduces a novel mathematical model exploring host-microbiota interactions, integrating dynamics of the colonic epithelial crypt, microbial metabolic functions, inflammation sensitivity and colon flows in a transverse section. The model considers metabolic shifts in epithelial cells based on butyrate and hydrogen sulfide concentrations, innate immune pattern recognition receptor activation, microbial oxygen tolerance and the impact of antimicrobial peptides on the microbiota. Using the model, we demonstrated that a high-protein, low-fibre diet exacerbates detrimental interactions and compromises beneficial symbiotic resilience, underscoring a destabilizing effect towards an unhealthy state. Moreover, the proposed model provides essential insights into oxygen levels, fibre and protein breakdown, and basic mechanisms of innate immunity in the colon and offers a crucial understanding of factors influencing the colon environment.

Spatial metabolomics using mass-spectrometry imaging to decipher the impact of high red meat diet on the colon metabolome in rat

Colorectal cancer (CRC) is the third most common cancer in the world with a higher prevalence in the developed countries, mainly caused by environmental and lifestyle factors such as diet, particularly red meat consumption. The metabolic impact of high red meat consumption on the epithelial part of the colon was investigated using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MSI), to specifically analyze the epithelial substructure. Ten colons from rats fed for 100 days high red or white meat diet were subjected to untargeted MSI analyses using two spatial resolutions (100 μm and 10 μm) to evaluate metabolite changes in the epithelial part and to visualize the distribution of metabolites of interest within the epithelium crypts. Our results suggest a specific effect of red meat diet on the colonic epithelium metabolism, as evidenced by an increase of purine catabolism products or depletion in glutathione pool, reinforcing the hypothesis of increased oxidative stress with red meat diet. This study also highlighted cholesterol sulfate as another up-regulated metabolite, interestingly localized at the top of the crypts. Altogether, this study demonstrates the feasibility and the added value of using MSI to decipher the effect of high red meat diet on the colonic epithelium.

Spontaneous intoxication of sheep by the pollen beetle Astylus atromaculatus: 4 outbreaks in Uruguay and Argentina.

Astylus atromaculatus Blanchard is a native beetle of South America that feeds on pollen. During the summer of 2022-2023 in Argentina and Uruguay, an explosive infestation of these insects occurred in pastures in which ruminants were grazing. This was believed to be associated with a severe drought, which had significantly reduced the flowering of crops. Three farms in Uruguay and one in Argentina were visited to examine the flocks and perform autopsies. Affected sheep had watery diarrhea, anorexia, depression, and ruminal atony. The average morbidity, mortality, and case fatality rates were 7.5%, 4.3%, and 68%, respectively. The main gross findings in all animals were in the jejunum; the serosa had multifocal hemorrhages, and the mucosa was necrotic and covered by a pseudomembrane. Microscopically, the mucosa had partial-to-complete necrosis of the lamina propria, as well as loss of villus and crypt epithelium with neutrophilic infiltration. Overlying the necrotic mucosa was a pseudomembrane of fibrin, cell debris, desquamated epithelial cells, degenerate neutrophils, and bacteria. Many specimens of A. atromaculatus were in all paddocks in which sheep grazed, as well as in the ruminal content of the autopsied animals.

Cdc42 Rho GTPase Activity Sustains Epithelial Barrier Function in the Cystic Fibrosis Intestine

Increased paracellular permeability is a common manifestation of cystic fibrosis (CF) intestinal disease in people with CF and in CF mouse models. Increased paracellular permeability has been found in CF airway epithelium cultured in the absence of inflammatory factors, suggesting an inherent defect in CF epithelial barrier function (Weiser et al., Cell Physiol Biochem. 2011;28(2):289-96). CF transmembrane conductance regulator knockout ( Cftr KO) mouse intestinal crypts demonstrate an increase in epithelial cell proliferation, which correlates with an alkaline intracellular pH (pHi), a pHi-dependent increase in lateral cell membrane localization of the Wnt transducer Disheveled (Dvl), and increased Wnt/β-catenin signaling (Strubberg et al., Cell Mol Gastroenterol Hepatol. 2017 Dec 7;5(3):253-271). We hypothesized that the alkaline pHi of Cftr KO crypts also facilitates Dvl-dependent noncanonical Wnt signaling to increase Rho GTPase activity and thereby tight junction remodeling during increased proliferation. In Dvl2-eGFP rescue mice, Dvl2-eGFP intensity near the apical membrane of Cftr KO enteroid crypts was greater versus wild-type (WT) at both the crypt base and the transit-amplifying zone. Immunofluorescence studies of both freshly isolated crypts and early passage enteroids also found increased accumulation of the Rho GTPase Cdc42 at the tight junctions of Cftr KO versus WT crypts. Live imaging revealed a small increase in leak pathway permeability (3kD dextran) in Cftr KO as compared to WT murine enteroids. Increased leak permeability and Cdc42 tight junction localization were normalized in Cftr KO enteroids by suppressing proliferation through inhibition of Wnt/β-catenin signaling. There was no difference in Cdc42 expression in Cftr KO fresh crypts or enteroids, but initial studies show increased Cdc42 GTP-loaded activity in Cftr KO enteroids relative to WT. Similarly, CFTR KO human intestinal epithelial Caco-2 cells, which also show an alkaline pHi, increased Wnt/β-catenin signaling and a hyperproliferative phenotype, demonstrated a significant increase in GTP-loaded Cdc42 activity compared to WT cells. Inhibition of Cdc42 activity with ML141 (R&D Systems) resulted in a significant disruption of the Cftr KO epithelial barrier, whereas WT enteroid permeability was not affected by Cdc42 inhibition, Wnt inhibition or Wnt3a-induced proliferation. We conclude that increased Cdc42 Rho GTPase activity is cell-autonomous and is necessary for maintaining barrier integrity of the Cftr KO crypt epithelium. This work was supported by the Cystic Fibrosis Foundation grant CLARKE20G0 and the Crohn’s and Colitis Foundation grant #693938. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

DHX9 maintains epithelial homeostasis by restraining R-loop-mediated genomic instability in intestinal stem cells

Epithelial barrier dysfunction and crypt destruction are hallmarks of inflammatory bowel disease (IBD). Intestinal stem cells (ISCs) residing in the crypts play a crucial role in the continuous self-renewal and rapid recovery of intestinal epithelial cells (IECs). However, how ISCs are dysregulated in IBD remains poorly understood. Here, we observe reduced DHX9 protein levels in IBD patients, and mice with conditional DHX9 depletion in the intestinal epithelium (Dhx9ΔIEC) exhibit an increased susceptibility to experimental colitis. Notably, Dhx9ΔIEC mice display a significant reduction in the numbers of ISCs and Paneth cells. Further investigation using ISC-specific or Paneth cell-specific Dhx9-deficient mice demonstrates the involvement of ISC-expressed DHX9 in maintaining epithelial homeostasis. Mechanistically, DHX9 deficiency leads to abnormal R-loop accumulation, resulting in genomic instability and the cGAS-STING-mediated inflammatory response, which together impair ISC function and contribute to the pathogenesis of IBD. Collectively, our findings highlight R-loop-mediated genomic instability in ISCs as a risk factor in IBD.

A case of young male with recurrent acute pancreatitis caused by an intrapancreatic gastric duplication cyst

Gastric duplication cyst (GDC) is a rare gastrointestinal malformation that frequently occurs in the greater curvature of the gastric antrum or corpus. Herein, we reported a case of intrapancreatic GDC found as a result of recurring pancreatitis. A 15-year-old man experienced repeated episodes of acute pancreatitis and was found to have a cystic lesion in the pancreatic tail. Contrast-enhanced computed tomography revealed a 20-mm cystic lesion with an enhanced thick wall. Endoscopic ultrasonography revealed an anechoic cyst with a three-layered wall. Magnetic resonance cholangiopancreatography and endoscopic retrograde pancreatography (ERP) revealed a connection between the cyst and the main pancreatic duct (MPD), and the duplication of the MPD. ERP showed the pancreatic duct stenosis downstream of the cyst. Although preoperative diagnosis was difficult, distal pancreatectomy was performed to prevent recurrence of pancreatitis. Pathological examination revealed that the cystic lesion was circumferentially surrounded by the pancreatic parenchyma. The epithelial lining of the cyst was crypt epithelium containing the fundic or pyloric glands and surrounded by a smooth muscle layer. The final diagnosis was intrapancreatic GDC.

Number of intraepithelial lymphocytes and presence of a subepithelial band in normal colonic mucosa differs according to stainings and evaluation method

Chronic watery diarrhea is a frequent symptom. In approximately 10% of the patients, a diagnosis of microscopic colitis (MC) is established. The diagnosis relies on specific, but sometimes subtle, histopathological findings. As the histology of normal intestinal mucosa vary, discriminating subtle features of MC from normal tissue can be challenging and therefore auxiliary stainings are increasingly used. The aim of this study was to determine the variance in number of intraepithelial lymphocytes (IELs) and presence of a subepithelial band in normal ileum and colonic mucosa, according to different stains and digital assessment. Sixty-one patients without diarrhea referred to screening colonoscopy due to a positive feacal blood test and presenting with endoscopically normal mucosa were included. Basic histological features, number of IELs, and thickness of a subepithelial band was manually evaluated and a deep learning-based algorithm was developed to digitally determine the number of IELs in each of the two compartments; surface epithelium and cryptal epithelium, and the density of lymphocytes in the lamina propria compartment. The number of IELs was significantly higher on CD3-stained slides compared with slides stained with hematoxylin-and-eosin (HE) (p<0.001), and even higher numbers were reached using digital analysis. No significant difference between right and left colon in IELs or density of CD3-positive lymphocytes in lamina propria was found. No subepithelial band was present in HE-stained slides while a thin band was visualized on special stains. Conclusively, in this cohort of prospectively collected ileum and colonic biopsies from asymptomatic patients, the range of IELs and detection of a subepithelial collagenous band varied depending on the stain and method used for assessment. As assessment of biopsies from patients with diarrhea constitute a considerable workload in the pathology departments digital image analysis is highly desired. Knowledge provided by the present study highlight important differences that should be considered before introducing this method in the clinic.

Effects of Letrozole Treatment and Vitamin C Supplementation on Morphology, Endoplasmic Reticulum Stress, Programmed Cell Death, and Oxidative Stress in the Small Intestine of Adult Male Rats.

Estrogens are hormones that play an important role in the digestive tract, including in men. Letrozole is an inhibitor of cytochrome P450 aromatase, an enzyme converting androgens to estrogens. The use of letrozole may cause oxidative stress and endoplasmic reticulum stress in the cells. Factors modulating cellular stress may include vitamin C. The purpose of this study was to examine whether letrozole and/or vitamin C supplementation can affect the morphology of the small intestine, the parameters of endoplasmic reticulum stress, programmed cell death markers, and oxidative damage. Three-month-old male rats were divided into four groups and treated with the following: (I) CTRL-water; (II) CTRL+C-L-ascorbic acid; (III) LET-letrozole; and (IV) LET+C-letrozole + L-ascorbic acid. The morphometrical measurements included epithelial thickness, crypt and lumen area, crypt perimeter, nuclei number in the crypt, and the cell size of crypts. The expression levels of PERK, caspase-3, and catalase were determined. Significant differences in the morphometrical measurements and immunoexpression were observed. This may indicate that chronic treatment with letrozole can affect morphology and induce ER stress, oxidative stress, and programmed cell death in the epithelial cells of the small intestine of adult male rats. Vitamin C supplementation exerts an effect on some parameters of the molecular processes.

Changes in Tight Junction Protein Expression Levels but Not Distribution in Commercial White and Brown Laying Hens Supplemented with Chondrus crispus or Ascophyllum nodosum Seaweed.

It is proposed that prebiotic diet supplements improve intestinal function, in part by improving the barrier function of the intestinal epithelium with an associated increase in the expression of tight junction proteins, including occludin and zonula occludens-1 (ZO-1). We examined the expression of these proteins in two strains of laying hens (Lohman LSL-lite (White) and Lohman Brown-lite (Brown)) who were supplemented or not with 3% Chondrus crispus or 0.5% Ascophyllum nodosum seaweeds from 31 to 72 weeks of age. Occludin was localized to the lateral surfaces and across the intestinal epithelium in all animals. Reactivity for ZO-1 was concentrated at the apicolateral epithelial cell membrane border. Mood's median test indicated that White hens may express more occludin in villus epithelium (median intensity 3.5 vs. 2.5 in Brown hens, p = 0.06) but less ZO-1 in the deep cryptal epithelium (median intensity 1.5 vs. 2.5 in Brown hens, p = 0.06). Western blotting also showed higher levels of occludin in White than Brown hens (p < 0.05). A decrease in ZO-1 Western blot expression was associated with Chondrus crispus supplementation in comparison to controls (p < 0.05), but not with Ascophyllum nodosum supplementation (p > 0.05). In conclusion, genetic strain and dietary seaweed supplements affect tight junction regulatory protein expression levels but do not impact the anatomical distribution, as seen in cryosections.

P406 A novel active learning-based digital pathology protocol annotation for histologic assessment in Ulcerative Colitis using PICaSSO Histologic Remission Index (PHRI)

Abstract Background Histologic remission (HR) is a critical treatment target in Ulcerative Colitis (UC). Among several scoring systems, the PICaSSO Histologic Remission Index (PHRI) simplifies HR assessment by evaluating the presence of neutrophils in the bowel tissue. Our artificial intelligence (AI) system built upon PHRI showed remarkable accuracy in HR assessment. PHRI assess neutrophils in four different regions of interest, so segmentation of these compartments is crucial to predict PHRI automatically. However, creating labelled histopathological datasets to train fully-supervised segmentation models takes time and effort. Hence, this study explores the impact of an active learning (AL) algorithm on enhancing image segmentation to alleviate the burden of detailed pathologists’ annotation and to standardise protocol annotation. Methods Biopsy samples from an international real-life prospective UC study were digitised into whole slide images (WSI). Initial annotations of superficial epithelium, lumen and epithelium of crypts and lamina propria for 33 WSI were employed to train a U-Net segmentation model at baseline. An AL framework was employed to iteratively select and annotate 15 unannotated images while selecting those with the highest uncertainty. Uncertainty was calculated using Least confidence sampling, Margin Sampling, and Shannon Entropy. The most informative samples, based on the average of the three uncertainty measure, were selected in consecutive batches of 5 images, and pathologists were enlisted in a human-in-the-loop process to refine annotations. Subsequently, the segmentation model was retrained by incorporating the newly refined annotated samples, and its performance was assessed using a fully annotated test set of 19 WSI. Results Following the baseline model training, the model’s segmentation performance assessed by the Dice score and Intersection over Union (IoU) was 0.622 and 0.386, respectively (see Table 1). Applying the AL algorithm with newly annotated images notably improved model performance, especially with 10 images (Dice=0.651, IoU=0.415). However, training the model with an additional 5 newly annotated images, which exhibited lower uncertainty, did not yield further improvement (Dice = 0.651, IoU = 0.415). Thus, the 10 annotated WSI demonstrating more uncertainty resulted crucial for the AL framework. Conclusion This novel AL-based iterative framework exhibits promise in standardising digital tissue annotation by our PHRI-based AI model. It offers a novel approach for both clinical trial and clinical practice, aiming to alleviate the burden of WSI labelling and reduce the bias of annotation, thereby improving histological assessment in UC.

Intestinal Inflammation and Regeneration-Interdigitating Processes Controlled by Dietary Lipids in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a disease of chronic inflammatory conditions of the intestinal tract due to disturbance of the inflammation and immune system. Symptoms of IBD include abdominal pain, diarrhea, bleeding, reduced weight, and fatigue. In IBD, the immune system attacks the intestinal tract's inner wall, causing chronic inflammation and tissue damage. In particular, interlukin-6 and interlukin-17 act on immune cells, including T cells and macrophages, to amplify the immune responses so that tissue damage and morphological changes occur. Of note, excessive calorie intake and obesity also affect the immune system due to inflammation caused by lipotoxicity and changes in lipids supply. Similarly, individuals with IBD have alterations in liver function after sustained high-fat diet feeding. In addition, excess dietary fat intake, along with alterations in primary and secondary bile acids in the colon, can affect the onset and progression of IBD because inflammatory cytokines contribute to insulin resistance; the factors include the release of inflammatory cytokines, oxidative stress, and changes in intestinal microflora, which may also contribute to disease progression. However, interfering with de novo fatty acid synthase by deleting the enzyme acetyl-CoA-carboxylase 1 in intestinal epithelial cells (IEC) leads to the deficiency of epithelial crypt structures and tissue regeneration, which seems to be due to Lgr5+ intestinal stem cell function. Thus, conflicting reports exist regarding high-fat diet effects on IBD animal models. This review will focus on the pathological basis of the link between dietary lipids intake and IBD and will cover the currently available pharmacological approaches.

Clinical, endoscopic, and pathological analyses of 14 cases of gastric adenocarcinoma of the fundic gland type

Objective: Gastric adenocarcinoma of the fundic gland type (GA-FG) is rare and often occurs in patients who are not infected with Helicobacter pylori. The current study analyzed and summarized the clinical, endoscopic, and pathological features of GA-FG, in an effort to improve its diagnosis. Methods: Patients who were diagnosed with GA-FG and treated with endoscopic submucosal dissection (ESD) resection at the Department of Gastroenterology, First Affiliated Hospital of Zhejiang Chinese Medical University from January 1st 2020 to October 1st 2022 were included in the study. Their clinical manifestations, endoscopic features, pathological immunohistochemistry, and other characteristics were analyzed. Results: A total of 14 patients with GA-FG were included in the study, 5 males and 9 females, with a mean age of 59 years. Most had no substantial clinical manifestations. Twelve patients were H. pylori-negative, all patients underwent ESD resection, and all patients survived during the follow-up period of 13±9 months. Eleven patients had postoperative endoscopic follow-up records, and no recurrence was detected. Fifteen lesions were detected (2 were present in 1 patient). Twelve were located in the upper 1/3 of the stomach, 10 were ≤ 1 cm in diameter, 12 had a morphology of type 0-Ⅱa, 8 had visible discoloration changes, and 12 had visible vasodilation on the surface. Magnified endoscopy and narrow-band imaging indicated that 12 of the lesions had enlarged marginal crypt epithelium, without any obvious microvascular pattern abnormalities and no obvious borderline. After resection the pathological specimens were all without vascular infiltration, and there was no atrophy of the mucosa at the edge of the lesion. In immunohistochemistry analyses MUC-2 was negative in all cases. MUC5AC was negative in 11 cases, MUC-6 was positive in all cases, and Ki-67 was ≤ 5% in 12 cases. Conclusions: GA-FG is a newly identified type of gastric cancer with low malignancy and a good prognosis. Characteristic discoloration and surface dilated vessels are often evident endoscopically. Enlarged marginal crypt epithelium and no visible boundary lines are often apparent in magnification endoscopy and narrow band imaging.