Synthesis and pharmacodynamic evaluation of Dihydropteridone derivatives against PDCoV in vivo and in vitro

Porcine Delta Coronavirus (PDCoV) infection can induce serious dehydration, diarrhea and even death of piglets, which has caused huge losses to the breeding industry. PDCoV has been reported to have the potential for cross species transmission, and even reports of infecting humans have emerged. At present, there are still no effective prevention and control measures for PDCoV. In this study, we have designed and synthesized a series of unreported Dihydropteridone derivatives. All of these compounds were evaluated for the against PDCoV in vivo and in vitro for the first time. In this study, antiviral activity (17.34 ± 7.20 μM) and low cytotoxicity (>800 μM) was found in compound W8. Compound W8 exerts antiviral effect on PDCoV by inhibiting cell apoptosis and inflammatory factors caused by virus infection in vitro. In addition, lung and small intestinal lesions caused by PDCoV infection in mice could be significantly reduced by compound W8. These findings highlight the potential of compound W8 as a valuable therapeutic option against PDCoV infection, and lay a foundation for further research and development in this field.

Is there a fast track ("Darmstrasse") for fluids in the small intestine? Evidence from magnetic resonance imaging

BACKGROUND

The transit and distribution pattern of fluids in the small intestine is a key parameter for the dissolution and absorption of drugs. Although some information is known about the small intestinal water content after administration of fluid volumes and meals, the intestinal transit of orally ingested fluids and solutions has been barely investigated. The aim of this three-arm, cross-over, 9-subject human study was to investigate the transit of orally ingested water in the small intestine under fasting and postprandial conditions using MRI. To identify the ingested water, manganese gluconate, which can be identified with T1-weighted MRI sequences, was added as a marker. Using Horos (DICOM software), quantification of the distribution of Mn2+ ions in the gastrointestinal tract in fasted versus fed state (standard meal by FDA guidance and a light meal) was possible. The distribution and approximate wetted intestinal length was very similar in the fasting and postprandial states, suggesting rapid transport of water ingested after a meal through the chyme-filled small intestine in continuation of the "Magenstrasse" (stomach road). In some subjects, manganese gluconate reached deeper parts of the small intestine even more quickly in the postprandial state than in the fasting arm of the study. A deeper understanding of the behaviour of solutes in the gastrointestinal tract is fundamental to a mechanistic explanation for the kinetic interaction between food and drug intake (food effects).

Carrageenan films as promising mucoadhesive ocular drug delivery systems

Polymer mucoadhesive films being developed for use in ophthalmology represent a new tool for drug delivery and are considered an alternative to traditional dosage forms. Due to their mucoadhesive properties, carrageenans (CRGs) are widely used in various forms for drug delivery. In this study, films based on CRGs of various structural types (κ/β, κ, x, and λ) for use in ophthalmology were studied. The films were loaded with the active substance echinochrome (ECH), a sea urchin pigment used in ophthalmology. Spectral data showed that ECH remained stable after its incorporation into the CRG films and did not oxidize for at least six months. Hydrophilic CRG films with a thickness of 10-12 µm were characterized in terms of their swelling and mucoadhesive properties. The rheological properties of solutions formed after film dissolution in artificial tears were also assessed. κ- and κ/β-CRG films with ECH exhibited pseudoplastic behavior after rehydrating films with an artificial tear solution. The CRG-loaded films had different swelling characteristics depending on the structure of the CRG used. The films based on highly sulfated CRGs dissolved in artificial tears, while the films of low-sulfated κ/β-CRG exhibited limited swelling. All studied ECH-loaded films exhibited mucoadhesive properties, which were evaluated by a texture analyzer using mucous tissue of the small intestine of the pig as a model. There was a slight prolongation of ECH release from CRG films in artificial tears. The effect of CRG/ECH on the epithelial cell lines of the outer shell of the human eye was investigated. At low concentrations, ECH in the composition of the CRG/ECH complex had no cytotoxic effect on corneal epithelial and conjunctival human cells. The use of ECH-containing films can prevent the drug from being immediately washed away by tears and help to retain it by increasing viscosity and having mucoadhesive properties.

From intestinal failure to transplantation: Review on the current need for transplant indications under multidisciplinary transplant programs worldwide

INTRODUCTION

Intestinal failure, defined as the loss of gastrointestinal function to the point where nutrition cannot be maintained by enteral intake alone, presents numerous challenges in children, not least the timing of consideration of intestine transplantation.

OBJECTIVES

To describe the evolution of care of infants and children with intestinal failure including parenteral nutrition, intestine transplantation, and contemporary intestinal failure care.

METHODS

The review is based on the authors' experience supported by an in-depth review of the published literature.

RESULTS

The history of parenteral nutrition, including out-patient (home) administration, and intestine transplantation are reviewed along with the complications of intestinal failure that may become indications for consideration of intestine transplantation. Current management strategies for children with intestinal failure are discussed along with changes in need for intestine transplantation, recognizing the difficulty in generalizing recommendations due to the high level of heterogeneity of intestinal pathology and residual bowel anatomy and function.

DISCUSSION

Advances in the medical and surgical care of children with intestinal failure have resulted in improved transplant-free survival and a significant fall in demand for transplantation. Despite these improvements a number of children continue to fail rehabilitative care and require intestine transplantation as life-saving therapy or when the burden on ongoing parenteral nutrition becomes too great to bear.

Mechanisms driving fasting-induced protection from genotoxic injury in the small intestine

Genotoxic agents such as doxorubicin (DXR) can cause damage to the intestines that can be ameliorated by fasting. How fasting is protective and the optimal timing of fasting and refeeding remain unclear. Here, our analysis of fasting/refeeding-induced global intestinal transcriptional changes revealed metabolic shifts and implicated the cellular energetic hub mechanistic target of rapamycin complex 1 (mTORC1) in protecting from DXR-induced DNA damage. Our analysis of specific transcripts and proteins in intestinal tissue and tissue extracts showed that fasting followed by refeeding at the time of DXR administration reduced damage and caused a spike in mTORC1 activity. However, continued fasting after DXR prevented the mTORC1 spike and damage reduction. Surprisingly, the mTORC1 inhibitor, rapamycin, did not block fasting/refeeding-induced reduction in DNA damage, suggesting that increased mTORC1 is dispensable for protection against the initial DNA damage response. In Ddit4-/- mice [DDIT4 (DNA-damage-inducible transcript 4) functions to regulate mTORC1 activity], fasting reduced DNA damage and increased intestinal crypt viability vs. ad libitum-fed Ddit4-/- mice. Fasted/refed Ddit4-/- mice maintained body weight, with increased crypt proliferation by 5 days post-DXR, whereas ad libitum-fed Ddit4-/- mice continued to lose weight and displayed limited crypt proliferation. Genes encoding epithelial stem cell and DNA repair proteins were elevated in DXR-injured, fasted vs. ad libitum Ddit4-/- intestines. Thus, fasting strongly reduced intestinal damage when normal dynamic regulation of mTORC1 was lost. Overall, the results confirm that fasting protects the intestines against DXR and suggests that fasting works by pleiotropic - including both mTORC1-dependent and independent - mechanisms across the temporally dynamic injury response.NEW & NOTEWORTHY New findings are 1) DNA damage reduction following a 24-h fast depends on the timing of postfast refeeding in relation to chemotherapy initiation; 2) fasting/refeeding-induced upregulation of mTORC1 activity is not required for early (6 h) protection against DXR-induced DNA damage; and 3) fasting increases expression of intestinal stem cell and DNA damage repair genes, even when mTORC1 is dysregulated, highlighting fasting's crucial role in regulating mTORC1-dependent and independent mechanisms in the dynamic recovery process.

Road map to small bowel endoscopy quality indicators

PURPOSE OF REVIEW

Quality indicators for upper and lower gastrointestinal endoscopy are well established and linked to patient outcomes. However, there is a perceived gap in the development and implementation of quality indicators for small bowel endoscopy. In this review, we aimed to discuss the development of quality indicators in small bowel endoscopy and their implementation in clinical practice.

RECENT FINDINGS

The proposed quality indicators for small bowel endoscopy focus on process measures, which mainly evaluate the procedural aspects, rather than the outcomes or the overall patient experience. These quality indicators have rarely been studied in clinical practice, leading to a limited understanding of their applicability and impact on patient outcomes and experience.

SUMMARY

Real-world studies evaluating the quality indicators of small bowel endoscopy are warranted to establish an evidence-based framework for their practical application and effectiveness. Linking these indicators to relevant patient outcomes is crucial for their broader acceptance and implementation.

Use of multiple admission variables better predicts intestinal strangulation in horses with colic than peritoneal or the ratio of peritoneal:blood l-lactate concentration

BACKGROUND

Early identification of strangulating obstruction (SO) in horses with colic improves outcomes, yet early diagnosis of horses requiring surgery for SO often remains challenging.

OBJECTIVES

To compare blood and peritoneal fluid l-lactate concentrations, peritoneal:blood l-lactate ratio, peritoneal minus blood (peritoneal-blood) l-lactate concentration and other clinical variables for predicting SO and SO in horses with small intestinal lesions (SO-SI) and then to develop a multivariable model to predict SO and SO-SI.

STUDY DESIGN

Retrospective cohort.

METHODS

A total of 197 equids admitted to a referral institution for colic between 2016 and 2019 that had peritoneal fluid analysis performed at admission were included. Twenty-three admission variables were evaluated individually for the prediction of a SO or SO-SI and then using multivariable logistic regression. Odds ratios (ORs) with 95% confidence intervals (CI) and area under the curve of the receiver operator characteristic (AUC ROC) were calculated.

RESULTS

All variables performed better in the model than individually. The final multivariable model for predicting SO included marked abdominal pain (OR 5.31, CI 1.40-20.18), rectal temperature (OR 0.30, CI 0.14-0.64), serosanguineous peritoneal fluid (OR 35.34, CI 10.10-122.94), peritoneal-blood l-lactate (OR 1.77, CI 1.25-2.51), and peritoneal:blood l-lactate ratio (OR 0.36, CI 0.18-0.72). The AUC ROC was 0.91. The final multivariable model for predicting SO-SI included reflux volume (OR 0.69, CI 0.56-0.86), blood l-lactate concentration (OR 0.43, CI 0.22-0.87), serosanguineous peritoneal fluid (OR 4.99, CI 1.26-19.74), and peritoneal l-lactate concentration (OR 3.77, CI 1.82-7.81).

MAIN LIMITATIONS

Retrospective, single-hospital study design.

CONCLUSIONS

Blood and peritoneal fluid l-lactate concentrations should be interpreted in conjunction with other clinical variables. The relationship between peritoneal and blood l-lactate concentration for predicting SO or SO-SI was complex when included in a multivariable model. Models to predict SO probably vary based on lesion location.

Surgical management of duodenal crohn's disease

BACKGROUND

Operative options for duodenal Crohn's disease include bypass, stricturoplasty, or resection. What factors are associated with operation selection and whether differences exist in outcomes is unknown.

METHODS

Patients with duodenal Crohn's disease requiring operative intervention across a multi-state health system were identified. Patient and operative characteristics, short-term surgical outcomes, and the need for future endoscopic or surgical management of duodenal Crohn's disease were analyzed.

RESULTS

40 patients underwent bypass (n = 26), stricturoplasty (n = 8), or resection (n = 6). Median age of diagnosis of Crohn's disease was 23.5 years, and over half of the patients had undergone prior surgery for CD. Operation type varied by the most proximal extent of duodenal involvement. Patients with proximal duodenal CD underwent bypass operations more commonly than those with mid- or distal duodenal disease (p = 0.03). Patients who underwent duodenal stricturoplasty more often required concomitant operations for other sites of small bowel or colonic CD (63%) compared to those who underwent bypass (39%) or resection (33%). No patients required subsequent surgery for duodenal CD at a median follow-up of 2.8 years, but two patients required endoscopic dilation (n = 1 after stricturoplasty, n = 1 after resection).

CONCLUSION

Patients who require surgery for duodenal Crohn's disease appear to have an aggressive Crohn's disease phenotype, represented by a younger age of diagnosis and a high rate of prior resection for Crohn's disease. Choice of operation varied by proximal extent of duodenal Crohn's disease.

Inflammatory bowel disease: recent developments

Paediatric-onset inflammatory bowel disease (IBD) is a complex and heterogenous condition. Incidence of disease in those aged <18 years has doubled over the last 25 years, with concurrent increased prevalence and no decrease in disease severity. The tools available at diagnosis for investigation have developed over the last 10 years, including better utilisation of faecal calprotectin, improved small bowel imaging and video capsule endoscopy. Alongside this, management options have increased and include biological and small molecule therapies targeting alternative pathways (such as interleukin 12/23, integrins and Janus kinase/signal transducers and activators of transcription, JAK-STAT pathways) and better understanding of therapeutic drug monitoring for more established agents, such as infliximab. Dietary manipulation remains an interesting but contentious topic.This review summarises some of the recent developments in the diagnosis, investigation and management of IBD in children and young people. IBD is increasingly recognised as a continuum of disease, with a proportion of patients presenting with classical Crohn's disease or ulcerative colitis phenotypes. Future implementation of personalisation and stratification strategies, including clinical and molecular biomarkers, implementation of predictors of response and outcome and use of additional therapies, will continue to require working within clinical networks and multiprofessional teams.

Colonization during a key developmental window reveals microbiota-dependent shifts in growth and immunity during undernutrition

BACKGROUND

Childhood undernutrition is a major global health challenge with devastating lifelong consequences. Linear growth stunting due to undernutrition has been linked to poor health outcomes, and mothers who experience growth stunting in childhood are more likely to give birth to stunted children later in life. Based on these findings, we hypothesized that intergenerational colonization of mice with microbiota from human donors with undernutrition may recapitulate certain immune and growth changes observed in this disorder.

RESULTS

To test this hypothesis, we developed a gnotobiotic murine model of undernutrition using microbiota from human infants with healthy or stunted growth trajectories. Intergenerational colonization with microbiota derived from children with growth stunting lead to less linear growth and the development of immune features of undernutrition and enteropathy, including intestinal villus blunting, lower liver IGF-1 and accumulation of intraepithelial lymphocytes and plasma cells in the small intestine. In contrast, colonization after weaning lead to fewer host phenotypic changes between these distinct microbial communities.

CONCLUSIONS

These results are broadly consistent with previous findings demonstrating that exposure of the immune system to microbial products during the weaning phase is a critical determinant of later life immune function. Overall, our results suggest intergenerational colonization with human microbiota samples is a useful approach with which to investigate microbiota-dependent changes in growth and immunity in early life. Murine models that capture the intergenerational and multifactorial nature of undernutrition are critical to understanding the underlying biology of this disorder. Video Abstract.

Spontaneous bowel evisceration through umbilical hernia in an adult non-cirrhotic patient

Few cases of spontaneous bowel evisceration (SBE) through umbilical hernias (UHs) in adult patients have been reported in the literature. Interestingly, the spontaneous rupture of the hernia sac is a rare complication usually seen in adult cirrhotic patients with persistent ascites or in patients with congenital wall defects. A man in his early 50s was admitted to our emergency department with SBE through a long-standing acquired UH. He was not clinically cirrhotic, although being HCV positive. Surgeons performed an urgent laparotomy with ileal resection, latero-lateral ileal anastomosis and direct hernioplasty without mesh. Given the rarity of this presentation, we reported it and reviewed the available literature on this subject. Elective hernioplasty is currently suggested to lower the risk of complications. Mesh placement should be preferred, but only if comorbidities and infectious risks do not contraindicate its use. In emergency situations, a direct hernia repair is preferred.

Intestinal Atresias: A Ten-Year Evaluation of Outcomes

INTRODUCTION

Intestinal atresia is a common cause of neonatal bowel obstruction. Atresias are often associated with other congenital anomalies. The purpose of the study was to evaluate associated anomalies, operative management, and postoperative outcomes of infants with intestinal atresia.

METHODS

A review of patients presenting to a single free-standing children's hospital from March 2012 through February 2022 was performed. The variables examined were type of atresia, additional congenital anomalies, type of operative intervention, and postoperative outcomes. Standard statistical methods were utilized.

RESULTS

A total of 75 patients with intestinal atresia were identified and several of these patients had multiple atresias. Isolated duodenal atresia patients were the most common (49.3%), followed by jejunal (32%) and ileal (12%). Mixed atresias were rare at 4%, with isolated pyloric and colonic also rare at 1.3% each. Malrotation was associated with 13% of patients and equally associated with duodenal and jejunoileal atresias. A low percentage (3%) of intestinal atresias was seen in conjunction with gastroschisis and concomitant malrotation. A majority of infants with duodenal atresia underwent standard duodenoduodenostomy (19% laparoscopic, 81% open). In infants with jejunoileal atresia, most underwent resection with primary anastomosis. A tapering enteroplasty was performed primarily in 13% of atresias. There were no significant differences noted in time to first feed or length of stay between those with and without tapering enteroplasty. Eleven percent of patients required subsequent intervention for stricture or small bowel obstruction. There was one death in this series.

CONCLUSIONS

Consistent with other literature, duodenal atresia was the most common type of intestinal atresia. However, we demonstrated that malrotation was equally associated with duodenal and jejunoileal atresias while prior reports had shown a higher association with duodenal atresia. In our patient population, the use of tapering enteroplasty did not appear to be associated with outcomes. Overall, these infants have a low morbidity and mortality rate with a rare need for reoperation.

Morphology of the small and large intestines of the six-banded armadillo (Euphractus sexcinctus) Linnaeus, 1758

Euphractus sexcinctus has a diverse diet, so it needs anatomical and habitual features to help it get its meals. Therefore, the objective is to study the morphology of the small and large intestines of the six-banded armadillo (E. sexcinctus). The research was authorized and approved under number 136/16. Six animals, obtained from victims of predatory hunting, were dissected for the research. For the anatomical analysis, the specimens were dissected and photographed. The fragments of each organ were submitted to histological routine to obtain slides stained with hematoxylin-eosin, toluidine blue and Masson's trichrome for further analysis. The small intestine has three parts: duodenum, jejunum, and ileum. Histologically, it has the typical four layers of tubular organs. The mucosa is covered by simple cylindrical epithelium with the presence of specializations in the form of microvilli and variation in the number of goblet cells, depending on the portion observed. In the duodenal portion, the presence of the serous layer was not observed. In the jejunal portion, it is possible to observe lymphoid tissue aggregates in the submucosa, which become more evident in the ileum. The large intestine is divided into cecum, colon, and rectum and has the same histological subdivisions as the small intestine, but with some specializations. The presence of simple cylindrical intestinal crypts is clearly observed and the presence of a large number of goblet cells, which increase as it approaches the rectum. In the submucosa of the large intestine, the presence of organized lymphoid plaques is detected. RESEARCH HIGHLIGHTS: The presence of large numbers of goblet cells, which increase as one approaches the rectum. The presence of organized lymphoid plaques is detected. The duodenal portion was not observed presence of the serous layer.

Role of Novel Motorized Enteroscopy in the Evaluation of Small Bowel Diseases: A Systematic Review and Meta-analysis

BACKGROUND AND AIM

Motorized spiral enteroscopy (MSE) has recently been introduced for small bowel evaluation. In this systematic review and meta-analysis, we aim to evaluate the safety and efficacy of MSE for evaluation of small bowel diseases.

METHODS

A literature search was performed in Embase, PubMed, Medline databases for studies evaluating MSE between January -2010 and October-2022. The primary outcome of the study was diagnostic yield with MSE. Secondary outcomes included technical success, procedure duration, depth of maximum insertion (DMI), rate of pan-enteroscopy and adverse events.

RESULTS

10 studies with 961 patients [581 (60.5%) males] were included in the analysis. 1068 MSE procedures were performed by antegrade route in 698, retrograde route in 215 and bidirectional in 155 patients. Technical success was achieved in 94.9% (95% CI 92.9% to 96.4%) procedures. The pooled diagnostic yield of MSE was 73.7% (95% CI 70.7% to 76.4%). Pooled rate of pan-enteroscopy by antegrade route was 21.9% (95% CI 18.1% to 26.1%), retrograde route was 6.9% (95% CI 2.4% to 18.3%) and combined route was 61.2% (95% CI 52.4% to 69.3%). Pooled rate of major adverse events was 1.9% (95% CI 1.2% to 3.2%).

CONCLUSIONS

MSE is a safe and effective tool for evaluating small bowel disorders. High diagnostic yield and low rate of adverse events make it a potential alternative to balloon enteroscopy. However, comparative trials are required in the future.

Early double-balloon enteroscopy was not related to better clinical outcomes in patients with suspected overt small bowel bleeding

BACKGROUND

Device-assisted enteroscopy has been used for over 20 years for the management of patients with suspected small bowel bleeding. Unlike esophagogastroduodenoscopy and colonoscopy, the appropriate timing of enteroscopy is still unknown. In recent guidelines, early enteroscopy is suggested to maximize diagnostic yield and therapeutic yield in patients with suspected small bowel bleeding. However, few studies have identified its influence on clinical outcomes, including mortality or rebleeding rate. We conducted this study to evaluate the influence of the timing of double-balloon enteroscopy on clinical outcomes in patients with suspected small bowel bleeding.

METHODS

Patients with overt small bowel bleeding who underwent double-balloon enteroscopy from January 2013 to February 2021 were retrospectively reviewed. Patients were categorized into an early enteroscopy group (≤14 days) and a nonearly enteroscopy group (>14 days). Clinical outcomes, including short-term mortality and rebleeding rate, long-term mortality and rebleeding rate, diagnostic yield, and therapeutic yield, were analyzed.

RESULTS

A total of 100 patients (mean age, 66.2 years; 53% male) were included, and 44 patients were stratified into the early enteroscopy group. The diagnostic yield, therapeutic yield, mortality, and rebleeding rate were similar between two groups. In multivariate conditional logistic regression analysis, there were no significant differences between two groups regarding the 30-day rebleeding rate (adjusted odds ratio [aOR], 1.43; 95% CI, 0.47-4.33), 90-day rebleeding rate (aOR, 1.18; 95% CI, 0.47-2.94), 30-day mortality rate (aOR, 1.29; 95% CI, 0.21-8.13), 90-day mortality rate (aOR, 1.94; 95% CI, 0.48-7.87), and 90-day bleeding-related mortality (aOR, 2.18; 95% CI, 0.24-19.52). The Kaplan-Meier survival curve analysis showed that the timing of DBE was not associated with the long-term rebleeding rate or mortality rate ( p = 0.57 and 0.83, respectively).

CONCLUSION

The timing of enteroscopy did not influence the clinical outcomes, including the short-term mortality rate, short-term rebleeding rate, long-term mortality rate, and rebleeding rate, in patients with suspected overt small bowel bleeding.

In-Ovo Glutamine Administration Enhances Intestinal Development and Functions in Broiler Chickens: Insights from Enteroid Models

BACKGROUND

Early life events play significant roles in tissue development and animal health in their later life. Early nutrition, through in-ovo delivery, has shown beneficial effects on improving intestinal health in broiler chickens. However, the underlying mechanism is not fully investigated. A recently developed enteroid culture technique allows investigations on intestinal epithelial functions that are close to physiologic conditions.

OBJECTIVES

In this study, we evaluated the short- and long-term effects of in-ovo administration of glutamine (Gln) on intestinal epithelial development and functions by using intestinal enteroid culture and tissue electrophysiologic analysis.

METHODS

A hundred eggs of commercial Cobb500 broilers were in-ovo injected with 0.2 mL of either phosphate-buffered saline (PBS) or 3% Gln at embryonic day 18 (E18). Chicks were killed on the day of hatch, and at 3- and 14-d posthatch. Enteroids were generated from the small intestine. After 4 d of culture, enteroids were harvested for 5-ethynyl-2'-deoxyuridine proliferation, fluorescein isothiocyanate-4 kDa dextran permeability, and glucose absorption assays. At day 3 (d3) and day 14 (d14), intestinal barrier and nutrient transport functions were measured by the Ussing chamber. The gene expression of epithelial cell markers, nutrient transporters, and tight-junction proteins were analyzed in both intestinal tissues and enteroids.

RESULTS

In comparison with the PBS control group, in-ovo Gln increased intestinal villus morphology, epithelial cell proliferation, and differentiation, and altered epithelial cell population toward increased number of enteroendocrine and goblet cells while decreasing Paneth cells. Enteroids gene expression of nutrient transporters (B0AT1, SGLT1, and EAAT3), tight junction (ZO2), glucose absorption, and barrier functions were enhanced on the day of hatch. Long-term increases of intestinal di-peptide and alanine transport were observed at day 14 posthatch.

CONCLUSIONS

Together our results suggested that the in-ovo injection of Gln stimulated intestinal epithelium proliferation and programmed the epithelial cell differentiation toward absorptive cells.

Duodenal microbiome in chronic kidney disease

BACKGROUND

The intestinal microbiome is involved in the pathogenesis of chronic kidney disease (CKD). Despite its importance, the microbiome of the small intestinal mucosa has been little studied due to sampling difficulties, and previous studies have mainly focused on fecal sources for microbiome studies. We aimed to characterize the small intestinal microbiome of CKD patients by studying the microbiome collected from duodenal and fecal samples of CKD patients and healthy controls.

METHODS

Overall, 28 stage 5 CKD patients and 21 healthy participants were enrolled. Mucosal samples were collected from the deep duodenum during esophagogastroduodenoscopy and fecal samples were also collected. The 16S ribosomal RNA gene sequencing using Qiime2 was used to investigate and compare the microbial structure and metagenomic function of the duodenal and fecal microbiomes.

RESULTS

The duodenal flora of CKD patients had decreased alpha diversity compared with the control group. On the basis of taxonomic composition, Veillonella and Prevotella were significantly reduced in the duodenal flora of CKD patients. The tyrosine and tryptophan metabolic pathways were enhanced in the urea toxin-related metabolic pathways based on the Kyoto Encyclopedia of Genes and Genomes database.

CONCLUSION

The small intestinal microbiome in CKD patients is significantly altered, indicating that increased intestinal permeability and production of uremic toxin may occur in the upper small intestine of CKD patients.

The road to refractory graft-versus-host disease is paved with good intentions

Refractory acute graft-versus-host disease (GVHD) occurs when the immune injury exceeds the capacity of injured tissues to regenerate and repair. While glucocorticoids have been used for decades to treat GVHD, Arnhold, Chang, and colleagues in this issue of the JCI question whether this approach can in fact be counterproductive. Using in vivo experimental models of GVHD and in vitro intestinal organoids, the study authors show that glucocorticoid exposure directly impeded small intestinal epithelial proliferation and survival, thus preventing the resolution of injury. These findings suggest that future treatment approaches for acute GVHD should include measures to reduce immune reactivity as well as interventions to actively promote tissue resilience.

cGMP-dependent kinase 2, Na+/H+ exchanger NHE3, and PDZ-adaptor NHERF2 co-assemble in apical membrane microdomains

AIM

Trafficking, membrane retention, and signal-specific regulation of the Na+/H+ exchanger 3 (NHE3) are modulated by the Na+/H+ Exchanger Regulatory Factor (NHERF) family of PDZ-adapter proteins. This study explored the assembly of NHE3 and NHERF2 with the cGMP-dependent kinase II (cGKII) within detergent-resistant membrane microdomains (DRMs, "lipid rafts") during in vivo guanylate cycle C receptor (Gucy2c) activation in murine small intestine.

METHODS

Small intestinal brush border membranes (siBBMs) were isolated from wild type, NHE3-deficient, cGMP-kinase II-deficient, and NHERF2-deficient mice, after oral application of the heat-stable Escherichia coli toxin (STa) analog linaclotide. Lipid raft and non-raft fractions were separated by Optiprep density gradient centrifugation of Triton X-solubilized siBBMs. Confocal microscopy was performed to study NHE3 redistribution after linaclotide application in vivo.

RESULTS

In the WT siBBM, NHE3, NHERF2, and cGKII were strongly raft associated. The raft association of NHE3, but not of cGKII, was NHERF2 dependent. After linaclotide application to WT mice, lipid raft association of NHE3 decreased, that of cGKII increased, while that of NHERF2 did not change. NHE3 expression in the BBM shifted from a microvillar to a terminal web region. The linaclotide-induced decrease in NHE3 raft association and in microvillar abundance was abolished in cGKII-deficient mice, and strongly reduced in NHERF2-deficient mice.

CONCLUSION

NHE3, cGKII, and NHERF2 form a lipid raft-associated signal complex in the siBBM, which mediates the inhibition of salt and water absorption by Gucy2c activation. NHERF2 enhances the raft association of NHE3, which is essential for its close interaction with the exclusively raft-associated activated cGKII.

Small Bowel Obstruction Secondary to a Spontaneous Intramural Jejunal Hematoma

N/a.

Mechanisms underlying the gut-brain communication: How enterochromaffin (EC) cells activate vagal afferent nerve endings in the small intestine

How the gastrointestinal tract communicates with the brain, via sensory nerves, is of significant interest for our understanding of human health and disease. Enterochromaffin (EC) cells in the gut mucosa release a variety of neurochemicals, including the largest quantity of 5-hydroxytryptamine (5-HT) in the body. How 5-HT and other substances released from EC cells activate sensory nerve endings in the gut wall remains a major unresolved mystery. We used in vivo anterograde tracing from nodose ganglia to determine the spatial relationship between 5-HT synthesizing and peptide-YY (PYY)-synthesizing EC cells and their proximity to vagal afferent nerve endings that project to the mucosa of mouse small intestine. The shortest mean distances between single 5-HT- and PYY-synthesizing EC cells and the nearest vagal afferent nerve endings in the mucosa were 33.1 ± 14.4 µm (n = 56; N = 6) and 70.3 ± 32.3 µm (n = 16; N = 6). No morphological evidence was found to suggest that 5-HT- or PYY-containing EC cells form close morphological associations with vagal afferents endings, or varicose axons of passage. The large distances between EC cells and vagal afferent endings are many hundreds of times greater than those known to underlie synaptic transmission in the nervous system (typically 10-15 nm). Taken together, the findings lead to the inescapable conclusion that communication between 5-HT-containing EC cells and vagal afferent nerve endings in the mucosa of the mouse small intestinal occurs in a paracrine fashion, via diffusion. New and Noteworthy None of the findings here are consistent with a view that close physical contacts occur between 5-HT-containing EC cells and vagal afferent nerve endings in mouse small intestine. Rather, the findings suggest that gut-brain communication between EC cells and vagal afferent endings occurs via passive diffusion. The morphological data presented do not support the view that EC cells are physically close enough to vagal afferent endings to communicate via fast synaptic transmission.

Colonic-enteric lumen-apposing metal stents: a promising and safe alternative for endoscopic management of small-bowel obstruction

BACKGROUND AND AIMS

Lumen-apposing metal stents (LAMSs) have revolutionized the treatment of various gastroenterologic conditions that previously required surgery. The use of LAMSs for the management of small-bowel obstruction (SBO) involves EUS-guided coloenterostomy (EUS-CE) between the colon and a dilated loop of the small intestine proximal to the point of obstruction. This procedure is potentially beneficial for patients with malignant SBO who are poor surgical candidates.

METHODS

A retrospective cohort study was conducted at 2 tertiary care hospitals. Patients who underwent EUS-CE for SBO were identified, and data regarding patient demographics, indication for the procedure, location of the obstruction, procedural details, and adverse events were collected. The primary outcome was technical success of the procedure. Secondary outcomes were clinical success, resolution of symptoms, ability to tolerate enteral nutrition, and adverse events.

RESULTS

Twenty-six patients who underwent the EUS-CE procedure were included. Technical success was achieved in all 26 patients, clinical success (resolution of obstructive symptoms) was achieved in 92.3% of patients (24/26), and the ability to resume enteral nutrition in 84.6% (22/26). Adverse events occurred in 4 patients (15.4%) and included bleeding (1/26), diarrhea (2/26), and postprocedure sepsis (1/26). Patients were followed for a mean of 54.8 days (range, 2-190).

CONCLUSIONS

This study highlights that EUS-CE with LAMSs can be performed with high technical and clinical success for the management of SBO, particularly in patients with malignant obstructions who are not suitable candidates for surgical interventions. Further research with larger sample sizes will be essential to substantiate its efficacy and safety.

Microbiota and Digestive Metabolites Alterations in Functional Dyspepsia

Functional dyspepsia (FD), a widespread and debilitating digestive disease, is thought to originate from disrupted gut-brain communication. The cause of FD is not completely understood, but recent evidence suggests it could be due to multiple factors and can vary among different patient groups. Factors like gut motility changes, increased sensitivity to pain in the gut, ongoing low-level inflammation, and increased gut permeability have all been linked to the development of FD. Additionally, changes in the gut microbiome have been suggested to play a significant role in the disease. The gut microbiota in the duodenum could either be a cause or a result of the immune and nervous system issues seen in FD, but the ways in which the gut flora in the small intestine affects gut function, digestive metabolites and symptoms are not yet clear, more studies being needed in order to completely assess the relationship between gastrointestinal microbiota and development and progression of FD. This review summarizes the available research on the relationship between FD and the microbiota and examines the various treatments, including probiotics, that have been shown to relieve symptoms. Finally, suggestions for improving diagnosis and treatment for those with FD are presented.

Astragalus membranaceus Polysaccharide Regulates Small Intestinal Microbes and Activates IL-22 Signal Pathway to Promote Intestinal Stem Cell Regeneration in Aging Mice

Aging can cause degenerative changes in multiple tissues and organs. Gastrointestinal diseases and dysfunctions are common in the elderly population. In this study, we investigated the effects of Astragalus membranaceus polysaccharide (APS) and Astragalus membranaceus ethanol extract (AEE) on age-related intestinal dysfunction and gut microbiota dysbiosis in naturally aging mice. The energy expenditure and physical activity of 23-month-old C57BL6/J mice were recorded using a metabolic cage system. Pathological changes in the intestine were evaluated using Alcian blue staining. The protein levels of leucine-rich repeats containing G protein-coupled receptor 5 (Lgr5) and Stat3 in the small intestine were determined using immunohistochemistry. The intestinal cell migration distance was assessed using bromodeoxyuridine (BrdU) immunofluorescence staining. The gene transcription levels of intestinal stem cell (ISC) markers and ISC-related signaling pathways were detected using quantitative real-time PCR (qRT-PCR). Microbiota analysis based on 16S rDNA was performed to evaluate the composition of the gut microbiota. APS and AEE improved a series of aging phenotypes in female but not in male aging mice. APS and AEE ameliorate intestinal dysfunction and histopathological changes in aging mice. APS had a more significant anti-aging effect than AEE, particularly on intestinal dysfunction. APS promotes ISC regeneration by activating the IL-22 signaling pathway. Cohousing (CH) experiments further confirmed that APS induced the IL-22 signaling pathway by increasing the abundance of Lactobacillus, thereby promoting the regeneration of ISCs. Our results show that APS may serve as a promising agent for improving age-related intestinal dysfunction.

Chronic arsenic exposure affects stromal cells and signaling in the small intestine in a sex-specific manner

Arsenic is a toxicant that is ingested through drinking water and food, exposing nearly 140 million people to levels above the 10 ppb guideline concentration. Studies have shown that arsenic affects intestinal stem cells (ISCs), but the mechanisms by which arsenic alters the formation of adult cells in the small intestine are not well understood. Signals derived from intestinal stromal cells initiate and maintain differentiation. The goal of this study is to evaluate arsenic's effect on intestinal stromal cells, including PdgfrαLo trophocytes, located proximal to the ISCs, and PdgfrαHi telocytes, located proximal to the transit-amplifying region and up the villi. Adult Sox9tm2Crm-EGFP mice were exposed to 0, 33, and 100 ppb sodium arsenite in their drinking water for 13 weeks, and sections of duodenum were examined. Flow cytometry indicated that arsenic exposure dose-responsively reduced Sox9+ epithelial cells and trended toward increased Pdgfrα+ cells. The trophocyte marker, CD81, was reduced by 10-fold and 9.0-fold in the 100 ppb exposure group in male and female mice, respectively. Additionally, a significant 2.2- to 3.1-fold increase in PdgfrαLo expression was found in male mice in trophocytes and Igfbp5+ cells. PdgfrαHi protein expression, a telocyte marker, was more prevalent along the villus/crypt structure in females, whereas Gli1 expression (telocytes) was reduced in male mice exposed to arsenic. Principle coordinate analysis confirmed the sex-dependent response to arsenic exposure, with an increase in trophocyte and decrease in telocyte marker expression observed in male mice. These results imply that arsenic alters intestinal mesenchymal cells in a sex-dependent manner.

Parenteral nutrition: a life-saving intervention for 4 months in short bowel syndrome-a case report and review of the literature

BACKGROUND

Short bowel syndrome (SBS) in adults is defined as having less than 180 to 200 cm of remaining small bowel. Many literature sources do not provide precise epidemiological data, and challenges in estimating the prevalence of SBS include its multifactorial etiology and varying definitions. The most common pathologies leading to SBS include Crohn disease, mesenteric ischemia, radiation enteritis, post-surgical adhesions, and post-operative complications.

CASE PRESENTATION

This article presents a clinical case of a 76-year-old Lithuanian patient who underwent parenteral nutrition for four months due to SBS. Before the following diagnosis, the patient had undergone two surgeries. During the hospitalization, life-threatening conditions such as stercoral peritonitis, septic shock, and acute respiratory failure, were observed and treated. As a result of SBS, hypoproteinemia and hypoalbuminemia developed, leading to the prescription of full parenteral nutrition. After correcting the malnutrition, a third surgery was performed, resulting in the discontinuation of parenteral nutrition and the resumption of a regular diet.

CONCLUSIONS

Parenteral nutrition is the sole effective method for preserving the lives of patients with a short segment of the intestine. While on parenteral nutrition, patients can be prepared for reconstructive surgery.

Skipped Aganglionic Lengthening Transposition (SALT) is highly effective to achieve enteral autonomy in selected patients with intestinal failure secondary to total intestinal aganglionosis

BACKGROUND

Intestinal Failure, parenteral nutrition (PN) dependence, and subsequent liver disease are the most challenging and life-threatening complications of short bowel syndrome experienced by patients with total intestinal aganglionosis. Skipped Aganglionic Lengthening Transposition (SALT) showed to be a promising procedure to overcome such problems. We herein report the results of two patients who underwent SALT at the Umberto Bosio Center for Digestive Diseases.

PATIENTS AND METHODS

Between November 2019 and July 2022, 2 patients with total intestinal aganglionosis underwent SALT as autologous intestinal lengthening procedure. Perioperative data and long-term outcomes are reported. Patient #1-A 18 month-old male (PN dependant) with 30 cm of ganglionated bowel at birth experienced a 35% increase of intestinal length after SALT (from 43 to 58 cm) thanks to three 5 cm interposed aganglionic loops. Postoperative course was uneventful and he was totally weaned by PN after 28 months postoperatively. He is without PN only receiving enteric feeding 53 months after the procedure. Patient #2-A 11 year-old female (PN dependant) with 100 cm of ganglionated jejunum underwent SALT at 11 years and experienced a 19% increase of bowel length thanks to four 5 to 7 cm interposed aganglionic loops. Postoperatively she required excision of two out of the four loops due to severe strictures and inadequate perfusion with a subsequent overall 10% increase of length after SALT. Of note, she improved significantly with a progressive reduction of PN that has been stopped after 18 months.

CONCLUSION

Skipped aganglionic lengthening transposition (SALT) seems to be very effective in improving nutrients absorption in patients with total intestinal aganglionosis by increasing absorptive bowel surface and decelerating intestinal flow for a longer and more effective contact of enteric material with ileal mucosa. Provided these impressive results are confirmed in the very long-term, SALT could become a valid alternative for the treatment of patients with total intestinal aganglionosis carrying at birth at least 20 to 30 cm of ganglionated jejunum.

STRUCTURAL EVALUATION OF INFLAMMATORY BOWEL DISEASE COMPREHENSIVE CARE UNITS IN BRAZIL

BACKGROUND

The most efficient way to prevent complications from inflammatory bowel disease (IBD) is to provide patients with optimized care. Nonetheless, in Brazil, there is no validated methodology for evaluating health services recognized as comprehensive care units (CCU), making it difficult to assess the quality of care provided.

OBJECTIVE

To understand the current scenario, map the distribution of centers and identify strengths and weaknesses, considering local and regional characteristics.

METHODS

The study was carried out in three phases. Initially, the Brazilian Organization for Crohn's disease and colitis (GEDIIB) developed 22 questions to characterize CCU in Brazil. In the second phase, all GEDIIB members were invited to respond to the survey with the 11 questions considered most relevant. In the last phase, an interim analysis of the results was performed, using the IBM SPSS Statistics v 29.0.1.0 software. Descriptive statistics were used to characterize the center's profile. The chi-square test was used to compare categorical variables.

RESULTS

There were 53 responses from public centers (11 excluded). Most centers were concentrated in the Southeastern (n=22/52.4%) and only 1 (2.4%) in the Northern region of Brazil. Thirty-nine centers (92.9%) perform endoscopic procedures, but only 9 (21.4%) have access to enteroscopy and/or small bowel capsule endoscopy. Thirty-three centers (78.6%) offer infusion therapy locally, 26 (61.9%) maintain IBD patient records, 13 (31.0%) reported having an IBD nurse, 34 (81.0%) have specific evidence-based protocols and only 7 (16.7%) have a patient satisfaction methodology. In the private scenario there were 56 responses (10 excluded). There is also a concentration in the Southeastern and Southern regions. Thirty-nine centers (84.8%) have access to endoscopic procedures and 19 perform enteroscopy and/or small bowel capsule endoscopy, more than what is observed in the public environment. Infusion therapy is available in 24 centers (52.2%). Thirty-nine centers (84.8%) maintain a specific IBD patient database, 17 (37%) have an IBD nurse, 36 (78.3%) have specific evidence-based protocols, and 22 (47. 8%) apply a patient satisfaction methodology.

CONCLUSION

IBD CCU in Brazil were mainly located in the Southeastern and Southern regions of the country. Most centers have dedicated multidisciplinary teams and IBD specialists. There is still a current need to improve the proportion of IBD nurses in IBD care in Brazil.

BACKGROUND

•In Brazil, there is no validated methodology for evaluating health services recognized as comprehensive care units (CCU), making it difficult to assess the quality of care provided.

BACKGROUND

•Most CCU were concentrated in the Southeast region and only one (2.4%) in the Northeast region of Brazil. This pattern follows the epidemiological trends of IBD in the country.

BACKGROUND

•There is still difficulty in accessing enteroscopy and/or small bowel capsule endoscopy in the public health system.

BACKGROUND

•Most centers have dedicated multidisciplinary teams and IBD specialist doctors.

BACKGROUND

•There is still a current need to improve the proportion of nurses treating IBD in Brazil.

Volvulus of the gastrointestinal tract

Volvulus describes the twisting of the intestine or colon around its mesentery. Intestinal obstruction and/or ischaemia are the most common complications of volvulus. Within the gastrointestinal tract, there is a preponderance towards colonic volvulus. The sigmoid is the most commonly affected segment, followed by the caecum, small intestine and stomach. Distinguishing between the differing anatomical locations of gastrointestinal volvulus can be challenging, but is important for the management and prognosis. This article focuses on the main anatomical sites of gastrointestinal volvulus encountered in clinical practice. The aetiology, presentation, radiological features and management options for each are discussed to highlight the key differences.

Species differences in small intestinal exposure-related epithelial vacuolation in rats and dogs treated with a heteroaryldihydropyrimidine molecule

Small intestinal epithelial vacuolation induced by a heteroaryldihydropyrimidine compound (HAP-1) was observed in rats but not in dogs at termination in screening toxicity studies, despite the plasma exposure being higher in dogs. To understand the species differences, investigational studies with multiple time points following single dose (SD) and 7-day repeated dose (RD) were conducted in both species at doses resulting in comparable plasma exposures. In rats, epithelial vacuolation in the duodenum and jejunum were observed at all time points. In dogs, transient vacuolation was noted at 8 h post-SD (SD_8h) and 4 h post-RD (RD_4 h), but not at termination (RD_24 h). Special stains demonstrated lipid accumulation within enterocytes in both species and intracytoplasmic inclusion bodies in rats. Transmission electron microscopy identified these inclusion bodies as endoplasmic reticulum (ER) membranous structures. Transcriptomic analysis on jejunal mucosa at SD_8 h and RD_24 h revealed perturbations of lipid metabolism-related genes at SD_8 h in both species, but not at RD_24 h in dogs. ER stress-related gene changes at both time points were observed in rats only. Despite comparable HAP-1 plasma exposures, the duodenum and jejunum tissue concentrations of HAP-1 and acyl glucuronide metabolite were >5- and >30-fold higher in rats than in dogs, respectively. In vitro, similar cytotoxicity was observed in rat and dog duodenal organoids treated with HAP-1. In conclusion, HAP-1-induced intestinal epithelial vacuolation was related to lipid metabolism dysregulation in both species and ER-related injuries in rats only. The species differences were likely related to the difference in intestinal exposure to HAP-1 and its reactive metabolite.

[Severe small bowel involvement and chronic intestinal pseudo-obstruction in systemic sclerosis (scleroderma): Pathophysiological, diagnostic and therapeutic basis, including parenteral nutrition]

Gastrointestinal involvement in systemic sclerosis can be severe, reaching the critical point of chronic intestinal pseudo-obstruction, secondary to major disorders of small bowel motility. It is associated with some clinical and biological characteristics, in particular the positivity of anti-fibrillarin/U3RNP antibodies. Chronic intestinal pseudo-obstruction (CIPO) is complicated by a small intestinal bacterial overgrowth that requires cyclic antibiotic therapy. CIPO leads to a reduction of the food intake, due to painful symptoms, nausea and vomiting caused by meals, and ultimately to severe malnutrition. Meal splitting is often transiently effective and patients require exogenous nutritional support, mostly parenteral. Systemic sclerosis is not an obstacle to initiation and long-term continuation of parenteral nutrition and central venous catheter implantation is not associated with an increased risk of cutaneous or infectious complications. However, continuation of long-term parenteral nutrition requires monitoring in an expert nutrition center in order to adapt nutritional volumes and intakes and to limit potentially fatal cardiac and hepatobiliary complications. In addition to nutrition, prokinetic treatments, whose side effects must be known, can be associated. Invasive procedures, whose risk-benefit ratio must be carefully assessed, can also be used to treat symptoms exclusively.

Spontaneous detachment of the spiral overtube from the endoscope in the upper esophagus: a case report and literature review of a rare complication during motorized spiral enteroscopy

BACKGROUND

Motorized spiral enteroscopy (MSE) is a recent modality for diagnostic and therapeutic examination of the small bowel using a spiral-shaped overtube with an integrated electric motor attached to an endoscope. With growing evidence of its efficacy, MSE is increasingly being used by endoscopic facilities. We herein present an uncommon case of the detachment of the spiral overtube from the endoscope during MSE.

CASE REPORT

We performed antegrade MSE in a 75-year-old female under general anesthesia for coagulation of multiple small-bowel arteriovenous malformations and resection of a polyp detected on a previous capsule endoscopy. The management was successful, and we had no passage difficulties. However, during the withdrawal phase of the enteroscope, the entire spiral overtube disconnected from the endoscopic shaft and became stuck in the esophagus and pharynx. Attempts to remove the lodged spiral using various endoscopic forceps, graspers, snares, or a dilatation balloon failed. Also, the laryngoscopic use of Magill forceps did not allow grabbing the spiral properly. Eventually, the spiral could be retrieved laryngoscopically with arthroscopic grasping forceps. This incident caused laryngeal swelling and bleeding lacerations of the upper esophagus, which were clipped on a subsequent gastroscopy. No further long-lasting complications occurred in the patient.

CONCLUSION

Detachment of the spiral from the enteroscope is a potentially life-threatening and challenging complication of MSE. Artificial ventilation under observation by an anesthesiologist allowed for calm management of this dangerous situation and increased the overall safety of the procedure. Hence, we believe that in the context of antegrade MSE, general anesthesia with endotracheal intubation should be mandatory.

RET Signaling Persists in the Adult Intestine and Stimulates Motility by Limiting PYY Release From Enteroendocrine Cells

BACKGROUND & AIMS

RET tyrosine kinase is necessary for enteric nervous system development. Loss-of-function RET mutations cause Hirschsprung disease (HSCR), in which infants are born with aganglionic bowel. Despite surgical correction, patients with HSCR often experience chronic defecatory dysfunction and enterocolitis, suggesting that RET is important after development. To test this hypothesis, we determined the location of postnatal RET and its significance in gastrointestinal (GI) motility.

METHODS

RetCFP/+ mice and human transcriptional profiling data were studied to identify the enteric neuronal and epithelial cells that express RET. To determine whether RET regulates gut motility in vivo, genetic, and pharmacologic approaches were used to disrupt RET in all RET-expressing cells, a subset of enteric neurons, or intestinal epithelial cells.

RESULTS

Distinct subsets of enteric neurons and enteroendocrine cells expressed RET in the adult intestine. RET disruption in the epithelium, rather than in enteric neurons, slowed GI motility selectively in male mice. RET kinase inhibition phenocopied this effect. Most RET+ epithelial cells were either enterochromaffin cells that release serotonin or L-cells that release peptide YY (PYY) and glucagon-like peptide 1 (GLP-1), both of which can alter motility. RET kinase inhibition exaggerated PYY and GLP-1 release in a nutrient-dependent manner without altering serotonin secretion in mice and human organoids. PYY receptor blockade rescued dysmotility in mice lacking epithelial RET.

CONCLUSIONS

RET signaling normally limits nutrient-dependent peptide release from L-cells and this activity is necessary for normal intestinal motility in male mice. These effects could contribute to dysmotility in HSCR, which predominantly affects males, and uncovers a mechanism that could be targeted to treat post-prandial GI dysfunction.

Enteric glial cell network function is required for epithelial barrier restitution following intestinal ischemic injury in the early postnatal period

Ischemic damage to the intestinal epithelial barrier, such as in necrotizing enterocolitis or small intestinal volvulus, is associated with higher mortality rates in younger patients. We have recently reported a powerful pig model to investigate these age-dependent outcomes in which mucosal barrier restitution is strikingly absent in neonates but can be rescued by direct application of homogenized mucosa from older, juvenile pigs by a yet-undefined mechanism. Within the mucosa, a postnatally developing network of enteric glial cells (EGCs) is gaining recognition as a key regulator of the mucosal barrier. Therefore, we hypothesized that the developing EGC network may play an important role in coordinating intestinal barrier repair in neonates. Neonatal and juvenile jejunal mucosa recovering from surgically induced intestinal ischemia was visualized by scanning electron microscopy and the transcriptomic phenotypes were assessed by bulk RNA sequencing. EGC network density and glial activity were examined by Gene Set Enrichment Analysis, three-dimensional (3-D) volume imaging, and Western blot and its function in regulating epithelial restitution was assessed ex vivo in Ussing chamber using the glia-specific inhibitor fluoroacetate (FA), and in vitro by coculture assay. Here we refine and elaborate our translational model, confirming a neonatal phenotype characterized by a complete lack of coordinated reparative signaling in the mucosal microenvironment. Furthermore, we report important evidence that the subepithelial EGC network changes significantly over the early postnatal period and demonstrate that the proximity of a specific functional population of EGC to wounded intestinal epithelium contributes to intestinal barrier restitution following ischemic injury.NEW & NOTEWORTHY This study refines a powerful translational pig model, defining an age-dependent relationship between enteric glia and the intestinal epithelium during intestinal ischemic injury and confirming an important role for enteric glial cell (EGC) activity in driving mucosal barrier restitution. This study suggests that targeting the enteric glial network could lead to novel interventions to improve recovery from intestinal injury in neonatal patients.

Differentiation of Crohn's disease, ulcerative colitis, and intestinal tuberculosis by dual-layer spectral detector CT enterography

AIM

To investigate the value of radiological features and energy spectrum quantitative parameters in the differential diagnosis of Crohn's disease (CD), ulcerative colitis (UC), and intestinal tuberculosis (ITB) by dual-layer spectral detector computed tomography (CT) enterography (CTE).

MATERIALS AND METHODS

Clinical and CTE data were collected from 182 patients with CD, 29 with UC, and 51 with ITB. CT images were obtained at the enteric phases and portal phases. The quantitative energy spectrum parameters were iodine density (ID), normalised ID (NID), virtual non-contrast (VNC) value, and effective atomic number (Z-eff). The area under curve (AUC) of the receiver operating characteristic curve (ROC) was calculated.

RESULTS

The vascular comb sign (p=0.009) and enlarged lymph nodes (p=0.001) were more common in patients with CD than UC or ITB. In the differentiation of moderate-severe active CD from UC, enteric phase NID (AUC, 0.938; p<0.001) and portal phase Z-eff (AUC, 0.925; p<0.001) had the highest accuracy, which were compared separately. In the differentiation of moderate-severe active CD from ITB, enteric phase NID (AUC, 0.906; p<0.001) and portal phase Z-eff (AUC, 0.947; p<0.001) had the highest accuracy; however, the AUC value was highest when the four parameters are combined (AUC, 0.989; p<0.001; AUC, 0.986; p<0.001; AUC, 0.936; p<0.001; and AUC, 0.986; p<0.001).

CONCLUSION

The present study shows that the combined strategies of four parameters have higher sensitivity and specificity in differentiating CD, UC, and ITB, and may play a key role in guiding treatment.

Pathological and immunohistochemical assessment of the impact of three different strains of swine enteric coronaviruses in the intestinal barrier

Swine enteric coronaviruses, such as porcine epidemic diarrhea virus (PEDV) or transmissible gastroenteritis virus (TGEV), have risen concern for the porcine industry and research community due to the increase in their virulence, their potential recombination capacity and the emergence of new variants. This in vivo study aims to compare the impact of three different strains of swine enteric coronaviruses [(two G1b (S-INDEL) PEDV strains and a recombinant TGEV-PEDV or Swine enteric coronavirus (SeCoV)] in the intestine of 3-weeks-old infected piglets, focusing on the pathology and main components of the intestinal barrier, including the number of goblet cells, and the expression of IgA as well as FoxP3, a regulatory T cell marker. Severity of lesions was evidenced in the three infected groups and was highly correlated with the viral load in feces and the frequency of viral antigen-positive cells. Furthermore, higher cellular death together with an increase in the expression of the FoxP3 marker was detected in the duodenum and jejunum of infected animals at 3 days post-infection. Our results highlight a recruitment of FoxP3+ cells in the small intestine of infected animals which may represent a response to the tissue damage caused by viral replication and cell death. Further studies should be addressed to determine the potential role of these cells during swine enteric coronavirus infections.

Strain specific differences in vitamin D3 response: impact on gut homeostasis

Vitamin D3 regulates a variety of biological processes irrespective of its well-known importance for calcium metabolism. Epidemiological and animal studies indicate a role in immune regulation, intestinal barrier function and microbiome diversity. Here, we analyzed the impact of different vitamin D3- containing diets on C57BL/6 and BALB/c mice, with a particular focus on gut homeostasis and also investigated effects on immune cells in vitro. Weak regulatory effects were detected on murine T cells. By trend, the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 suppressed IFN, GM-CSF and IL-10 cytokine secretion in T cells of C57BL/6 but not BALB/c mice, respectively. Using different vitamin D3-fortified diets, we found a tissue-specific enrichment of mainly CD11b+ myeloid cells but not T cells in both mouse strains e.g. in spleen and Peyer's Patches. Mucin Reg3γ and Batf expression, as well as important proteins for gut homeostasis, were significantly suppressed in the small intestine of C57BL76 but not BALB/c mice fed with a high-vitamin D3 containing diet. Differences between both mouse stains were not completely explained by differences in vitamin D3 receptor expression which was strongly expressed in epithelial cells of both strains. Finally, we analyzed gut microbiome and again an impact of vitamin D3 was detected in C57BL76 but not BALB/c. Our data suggest strain-specific differences in vitamin D3 responsiveness under steady state conditions which may have important implications when choosing a murine disease model to study vitamin D3 effects.

A non-human primate model for human norovirus infection

Norovirus infection can cause gastrointestinal disease in humans. Development of therapies and vaccines against norovirus have been limited by the lack of a suitable and reliable animal model. Here we established rhesus macaques as an animal model for human norovirus infection. We show that rhesus macaques are susceptible to oral infection with human noroviruses from two different genogroups. Variation in duration of virus shedding (days to weeks) between animals, evolution of the virus over the time of infection, induction of virus-specific adaptive immune responses, susceptibility to reinfection and preferential replication of norovirus in the jejunum of rhesus macaques was similar to infection reported in humans. We found minor pathological signs and changes in epithelial cell surface glycosylation patterns in the small intestine during infection. Detection of viral protein and RNA in intestinal biopsies confirmed the presence of the virus in chromogranin A-expressing epithelial cells, as it does in humans. Thus, rhesus macaques are a promising non-human primate model to evaluate vaccines and therapeutics against norovirus disease.

Compartment specific responses to contractility in the small intestinal epithelium

Tissues are subject to multiple mechanical inputs at the cellular level that influence their overall shape and function. In the small intestine, actomyosin contractility can be induced by many physiological and pathological inputs. However, we have little understanding of how contractility impacts the intestinal epithelium on a cellular and tissue level. In this study, we probed the cell and tissue-level effects of contractility by using mouse models to genetically increase the level of myosin activity in the two distinct morphologic compartments of the intestinal epithelium, the crypts and villi. We found that increased contractility in the villar compartment caused shape changes in the cells that expressed the transgene and their immediate neighbors. While there were no discernable effects on villar architecture or cell polarity, even low levels of transgene induction in the villi caused non-cell autonomous hyperproliferation of the transit amplifying cells in the crypt, driving increased cell flux through the crypt-villar axis. In contrast, induction of increased contractility in the proliferating cells of the crypts resulted in nuclear deformations, DNA damage, and apoptosis. This study reveals the complex and diverse responses of different intestinal epithelial cells to contractility and provides important insight into mechanical regulation of intestinal physiology.

Small intestinal volvulus in 47 cows

Objective

To describe the findings, treatment, and outcome of small intestinal volvulus (SIV) in 47 cows.

Animals and procedure

Retrospective analysis of medical records. Comparison of the findings for 18 surviving and 29 non-surviving cows.

Results

The most common abnormal vital signs were tachycardia (68.0%), tachypnea (59.6%), and decreased rectal temperature (51.1%). Signs of colic occurred in 66.0% of cows in the study. Rumen motility was reduced or absent in 93.6% of cows, and intestinal motility in 76.6%. Clinical signs on ballottement and/or percussion and simultaneous auscultation were positive on the right side in 78.7% of cows. Transrectal examination showed dilated small intestines in 48.9% of cows. The rectum contained little or no feces in 93.6% of cows. The principal laboratory abnormalities were hypocalcemia (74.1%), hypokalemia (73.8%), azotemia (62.8%), hypermagnesemia (61.6%), and hemoconcentration (60.0%). The principal ultrasonographic findings were dilated small intestines (87.1%) and reduced or absent small intestinal motility (85.2%). Forty-one of the 47 cows underwent right flank laparotomy and the SIV was reduced in 21 cows. When comparing the clinical and laboratory findings of 18 surviving and 29 non-surviving cows, the groups differed significantly with respect to severely abnormal general condition (16.7 versus 37.9%), rumen stasis (22.2 versus 79.3%), intestinal atony (16.7 versus 48.3%), serum urea concentration (6.5 versus 9.8 mmol/L), and serum magnesium concentration (0.98 versus 1.30 mmol/L). In summary, 38.3% of the cows were discharged and 61.7% were euthanized before, during, or after surgery.

Conclusion and clinical relevance

An acute course of disease, little or no feces in the rectum, and dilated small intestines were characteristic of SIV in this study population.

High-Energy Pacing in the Jejunum Elicits Pulsatile Segmental Contractions

OBJECTIVE

Compromised bowel function is associated with a range of motility disorders such as post-operative ileus and chronic intestinal pseudo-obstruction. Disordered or weak motility compromise the efficient movement of luminal contents necessary for digestion and nutrient absorption. This study investigated the potential of high-energy pacing to enhance contractions in the proximal jejunum of the small intestine.

METHODS

Pacing pulse parameters (pulse-width: 100 ms, 200 ms, 400 ms, pulse-amplitude: 4 mA, 6 mA, 8 mA) were systematically varied in the in vivo porcine jejunum (n = 7) and the induced contractile responses were evaluated using a video mapping system. Localized segmental contractions were quantified by measuring the intestinal diameter and thereby computing the strain. The impact of pacing parameters on contractile strain was investigated. Finally, histological studies were conducted on paced tissue to assess for potential tissue damage.

RESULTS

Segmental contractions were successfully induced at all pulse-settings and evaluated across 67 pacing sessions. In response to pacing, the intestine segment at the site of pacing contracted, with diameter reduced by 6-18%. Contractile response significantly increased with increasing pulse-amplitude. However, with increasing pulse-width, the increase in contractile response was significant only between 100 ms and 400 ms. Histology showed no tissue damage occurred when maximal pacing energy (pulse-amplitude = 4-8 mA, pulse-width = 400 ms, 5 minute duration) was applied.

CONCLUSION

High-energy pacing induced periodic segmental contractions in response to pacing pulses and the contractile strain was proportional to the energy applied on the intestine. The ability to enhance motility through pacing may hold promising therapeutic potential for bowel disorders and awaits clinical translation.

SIGNIFICANCE

Small intestine pacing elicits localized segmental contractions which increase in magnitude with increasing pulse settings. This study marks the first adaptation of video mapping techniques to track the pacing response in the small intestine.

Immune cell-intrinsic Ah receptor facilitates the expression of antimicrobial REG3G in the small intestine

The intestinal epithelial layer is susceptible to damage by chemical, physiological and mechanical stress. While it is essential to maintain the integrity of epithelium, the biochemical pathways that contribute to the barrier function have not been completely investigated. Here we demonstrate an aryl hydrocarbon receptor (AHR)-dependent mechanism facilitating the production of the antimicrobial peptide AMP regenerating islet-derived protein 3 gamma (REG3G), which is essential for intestinal homeostasis. Genetic ablation of AHR in mice impairs pSTAT3-mediated REG3G expression and increases bacterial numbers of Segmented filamentous bacteria (SFB) and Akkermansia muciniphila in the small intestine. Studies with tissue-specific conditional knockout mice revealed that the presence of AHR in the epithelial cells of the small intestine is not required for the production of REG3G through the phosphorylated STAT3-mediated pathway. However, immune-cell-specific AHR activity is necessary for normal expression of REG3G in all regions of the small intestine. A diet rich in broccoli, capable of inducing AHR activity, increases REG3G production when compared to a semi-purified diet that is devoid of ligands that can potentially activate the AHR, thus highlighting the importance of AHR in antimicrobial function. Overall, these data suggest that homeostatic antimicrobial REG3G production is increased by an AHR pathway intrinsic to the immune cells in the small intestine.