Distribution, function and physiological role of melatonin in the lower gut

Melatonin is a hormone with endocrine, paracrine and autocrine actions. It is involved in the regulation of multiple functions, including the control of the gastrointestinal (GI) system under physiological and pathophysiological conditions. Since the gut contains at least 400 times more melatonin than the pineal gland, a review of the functional importance of melatonin in the gut seems useful, especially in the context of recent clinical trials. Melatonin exerts its physiological effects through specific membrane receptors, named melatonin-1 receptor (MT1), MT2 and MT3. These receptors can be found in the gut and their involvement in the regulation of GI motility, inflammation and pain has been reported in numerous basic and clinical studies. Stable levels of melatonin in the lower gut that are unchanged following a pinealectomy suggest local synthesis and, furthermore, implicate physiological importance of endogenous melatonin in the GI tract. Presently, only a small number of human studies report possible beneficial and also possible harmful effects of melatonin in case reports and clinical trials. These human studies include patients with lower GI diseases, especially patients with irritable bowel syndrome, inflammatory bowel disease and colorectal cancer. In this review, we summarize the presently available information on melatonin effects in the lower gut and discuss available in vitro and in vivo data. We furthermore aim to evaluate whether melatonin may be useful in future treatment of symptoms or diseases involving the lower gut.

Differential activation of the human farnesoid X receptor depends on the pattern of expressed isoforms and the bile acid pool composition

The farnesoid X receptor (FXR) is a key sensor in bile acid homeostasis. Although four human FXR isoforms have been identified, the physiological role of this diversity is poorly understood. Here we investigated their subcellular localization, agonist sensitivity and response of target genes. Measurement of mRNA revealed that liver predominantly expressed FXRα1(+/-), whereas FXRα2(+/-) were the most abundant isoforms in kidney and intestine. In all cases, the proportion of FXRα(1/2)(+) and FXRα(1/2)(-) isoforms, i.e., with and without a 12bp insert, respectively, was approximately 50%. When FXR was expressed in liver and intestinal cells the magnitude of the response to GW4064 and bile acids differs among FXR isoforms. In both cell types the strongest response was that of FXRα1(-). Different efficacy of bile acids species to activate FXR was found. The four FXR isoforms shared the order of sensitivity to bile acids species. When in FXR-deficient cells FXR was transfected, unconjugated, but not taurine- and glycine-amidated bile acids, were able to activate FXR. In contrast, human hepatocytes and cell lines showing an endogenous expression of FXR were sensitive to both unconjugated and conjugated bile acids. This suggests that to activate FXR conjugated, but not unconjugated, bile acids require additional component(s) of the intracellular machinery not related with uptake processes, which are missing in some tumor cells. In conclusion, cell-specific pattern of FXR isoforms determine the overall tissue sensitivity to FXR agonists and may be involved in the differential response of FXR target genes to FXR activation.

Neuroendocrine tumors of the small bowels are on the rise: Early aspects and management

Neuroendocrine tumors of the small bowel are on the rise. In the US they have increased by 300%-500% in the last 35 years. At the same time their prognosis is much improved. Today, most neuroendocrine tumors (NETs) of the duodenum are detected "incidentally" and therefore recognized at an early stage. Duodenal NETs which are well differentiated, not larger than 10 mm and limited to the mucosa/submucosa can be endoscopically resected. The management of duodenal NETs ranging between 10 and 20 mm needs an interdisciplinary discussion. Endoscopic ultrasound is the method of choice to determine tumor size and depth of infiltration. Surgery is recommended for well-differentiated duodenal NET tumors greater than 20 mm, for localized sporadic gastrinomas (of any size) and for localized poorly differentiated NE cancers. Surgery is recommended for any ileal NET. Advanced ileal NETs with a carcinoid syndrome are treated with long-acting somatostatin analogs. This treatment significantly improves (progression-free) survival in patients with metastatic NETs of the ileum. For optimal NET management, tumor biology, type, localization and stage of the neoplasm, as well as the patient's individual circumstances have to be taken into account.

The queen's gut refines with age: longevity phenotypes in a social insect model

BACKGROUND

In social insects, identical genotypes can show extreme lifespan variation providing a unique perspective on age-associated microbial succession. In honey bees, short- and long-lived host phenotypes are polarized by a suite of age-associated factors including hormones, nutrition, immune senescence, and oxidative stress. Similar to other model organisms, the aging gut microbiota of short-lived (worker) honey bees accrue Proteobacteria and are depleted of Lactobacillus and Bifidobacterium, consistent with a suite of host senescence markers. In contrast, long-lived (queen) honey bees maintain youthful cellular function with much lower expression of oxidative stress genes, suggesting a very different host environment for age-associated microbial succession.

RESULTS

We sequenced the microbiota of 63 honey bee queens exploring two chronological ages and four alimentary tract niches. To control for genetic and environmental variation, we quantified carbonyl accumulation in queen fat body tissue as a proxy for biological aging. We compared our results to the age-specific microbial succession of worker guts. Accounting for queen source variation, two or more bacterial species per niche differed significantly by queen age. Biological aging in queens was correlated with microbiota composition highlighting the relationship of microbiota with oxidative stress. Queens and workers shared many major gut bacterial species, but differ markedly in community structure and age succession. In stark contrast to aging workers, carbonyl accumulation in queens was significantly associated with increased Lactobacillus and Bifidobacterium and depletion of various Proteobacteria.

CONCLUSIONS

We present a model system linking changes in gut microbiota to diet and longevity, two of the most confounding variables in human microbiota research. The pattern of age-associated succession in the queen microbiota is largely the reverse of that demonstrated for workers. The guts of short-lived worker phenotypes are progressively dominated by three major Proteobacteria, but these same species were sparse or significantly depleted in long-lived queen phenotypes. More broadly, age-related changes in the honey bee microbiota reflect the regulatory anatomy of reproductive host metabolism. Our synthesis suggests that the evolution of colony-level reproductive physiology formed the context for host-microbial interactions and age-related succession of honey bee microbiota.

Acute small bowel obstruction caused by endometriosis: A case report and review of the literature

Gastrointestinal involvement of endometriosis has been found in 3%-37% of menstruating women and exclusive localization on the ileum is very rare (1%-7%). Endometriosis of the distal ileum is an infrequent cause of intestinal obstruction, ranging from 7% to 23% of all cases with intestinal involvement. We report a case in which endometrial infiltration of the small bowel caused acute obstruction requiring emergency surgery, in a woman whose symptoms were not related to menses. Histology of the resected specimen showed that endometriosis was mainly prevalent in the muscularis propria and submucosa and that the mucosa was not ulcerated but had inflammation and glandular alteration. Endometrial lymph node involvement, with a cystic glandular pattern was also detected.

Long-term outcomes of catheterizable continent urinary channels: What do you use, where you put it, and does it matter?

INTRODUCTION

Appendicovesicostomy (APV) and Monti ileovesicostomy (Monti) are commonly used catheterizable channels with similar outcomes on short-term follow-up. Their relative long-term results have not been previously published.

OBJECTIVE

Our goal was to assess long-term durability of APV and Monti channels in a large patient cohort.

STUDY DESIGN

In this retrospective cohort study, we retrospectively reviewed consecutive patients ≤21 years old undergoing APV and Monti surgery at our institution (1990-2013). We collected data on demographics, channel type, location, continence and stomal and subfascial revisions. Kaplan-Meier survival and Cox proportional hazards analysis were used.

RESULTS

Of 510 patients meeting inclusion criteria, 214 patients had an APV and 296 had a Monti (50.5% spiral Monti). Median age at surgery was 7.4 years for APV (median follow-up: 5.7 years) and 8.7 years for Monti (follow-up: 7.7 years). Stomal stenosis, overall stomal revisions and channel continence were similar for APV and Monti (p ≥ 0.26). Fourteen APVs (6.5%) had subfascial revisions compared to 49 Montis (16.6%, p = 0.001). On survival analysis, subfascial revision risk at 10 years for APV was 8.6%, Monti channels excluding spiral umbilical Monti: 15.5% and spiral umbilical Monti: 32.3% (p < 0.0001, Figure). On multivariate regression, Monti was 2.09 times more likely than APV to undergo revision (p = 0.03). The spiral Monti to the umbilicus, in particular, was 4.23 times more likely than APV to undergo revision (p < 0.001). Concomitant surgery, gender, age and surgery date were not significant predictors of subfascial revision (p ≥ 0.17). Stomal location was significant only for spiral Montis.

DISCUSSION

Our study has several limitations. Although controlling for surgery date was a limited way of adjusting for changing surgical techniques, residual confounding by surgical technique is unlikely, as channel implantation technique was typically unrelated to channel type. We did not include complications managed conservatively or endoscopically. In addition, while we did not capture patients who were lost to follow-up, we attempted to control for this through survival analysis.

CONCLUSIONS

We demonstrate, durable long-term results with the APV and Monti techniques. The risk of channel complications continues over the channel's lifetime, with no difference in stomal complications between channels. At 10 years after initial surgery, Monti channels were twice as likely to undergo a subfascial revision (1 in 6) than APV (1 in 12). The risk is even higher in for the spiral umbilical Monti (1 in 3).

Development of the duodenal, ileal, jejunal and caecal microbiota in chickens

Background

The chicken intestinal microbiota plays a large role in chicken health and productivity and a greater understanding of its development may lead to interventions to improve chicken nutrition, disease resistance and welfare.

Results

In this study we examine the duodenal, jejunal, ileal and caecal microbiota of chickens from day of hatch to 5 weeks of age (day 1, 3, 7, 14 and week 5). DNA was extracted from intestinal content samples and the V4 region of the 16S rRNA gene was amplified and sequenced. We identified significant differences in microbial community composition, diversity and richness between samples taken from different locations within the chicken intestinal tract. We also characterised the development of the microbiota at each intestinal site over time.

Conclusions

Our study builds upon existing literature to further characterise the development of the chicken intestinal microbiota.

Amelioration of DSS-induced murine colitis by VSL#3 supplementation is primarily associated with changes in ileal microbiota composition

Inflammatory bowel diseases encompass gastrointestinal illnesses typified by chronic inflammation, loss of epithelial integrity and gastrointestinal microbiota dysbiosis. In an effort to counteract these characteristic perturbations, we used stem cells and/or a probiotic therapy in a murine model of Dextran Sodium Sulfate induced colitis to examine both their efficacy in ameliorating disease and impact on niche-specific microbial communities of the lower GI tract. Colitis was induced in C57BL/6 mice by administering 3% DSS in drinking water for 10 days prior to administering one of three treatment plans: daily probiotic (VSL#3) supplementation for 3 days, a single tail vein injection of 1x10 (6) murine mesenchymal stem cells, or both. Ileal, cecal and colonic sections were collected for microbiota and histological analyses. Microbiota profiling revealed distinct bacterial community compositions in the ileum, cecum and colon of control untreated animals, all of which were predicted in silico to be enriched for a number of discrete KEGG pathways, indicating compositional and functional niche specificity in healthy animals. DSS-treatment perturbed community composition in all three niches with ileal communities exhibiting the greatest change relative to control animals. Each treatment group exhibited treatment-specific alterations in microbiota composition in the lower GI tract, though disease scores were only improved in VSL#3-treated animals. The ileal microbiota were most profoundly altered in composition in this group of animals and characterized by significant Enterobacteriaceae enrichment compared with colitic mice (P<0.05).

Effects of probiotic bacteria on gastrointestinal motility in guinea-pig isolated tissue

AIM: To evaluate the intestinal motility changes evoked by 8 bacterial strains belonging to Bifidobacterium, Lactobacillus and Streptococcus genera within the probiotic preparation VSL#3.

METHODS: Ileum and proximal colon segments isolated from guinea-pigs were used as a study model. Entire cells and cell fractions (cell debris, cell wall fraction, cytoplasmatic fraction, proteinaceous and non-proteinaceous cytoplasmatic components) of VSL#3 strains and, as controls, Escherichia coli, Salmonella aboni and Bacillus licheniformis were tested in this in vitro model.

RESULTS: Among the bacterial cell fractions tested, only the cytoplasmatic fraction modified intestinal motility. Lactobacillus strains stimulated the contraction of ileum segment, whereas all probiotic strains tested induced proximal colon relaxation response. The non-proteinaceous cytoplasmatic components were responsible for the colon relaxation.

CONCLUSION: The results obtained in this study suggest that the proximal colon relaxation activity showed by the probiotic bacteria could be one of the possible mechanisms of action by which probiotics exert their positive effects in regulating intestinal motility.

Formula diet alters small intestine morphology, microbial abundance and reduces VE-cadherin and IL-10 expression in neonatal porcine model

BACKGROUND

Breastfeeding is associated with a variety of positive health outcomes in children and is recommended exclusively for the first 6 months of life; however, 50-70 % of infants in the US are formula-fed. To test the hypothesis that immune system development and function in neonates and infants are significantly influenced by diet, 2-day old piglets were fed soy or milk formula (n = 6/group/gender) until day 21 and compared to a sow-fed group (n = 6/gender).

METHODS

Histomorphometric analyses of ileum, jejunum and Peyer's patches were carried out, to determine the inflammation status, mRNA and protein expression of pro-inflammatory, anti-inflammatory and growth-related chemokines and cytokines.

RESULTS

In formula-fed animals, increases in ileum and jejunum villus height and crypt depth were observed in comparison to sow-fed animals (jejunum, p < 0.01 villus height, p < 0.04 crypt depth; ileum p < 0.001 villus height, p < 0.002 crypt depth). In formula-fed the lymphoid follicle size (p < 0.01) and germinal centers (p < 0.01) with in the Peyer's patch were significantly decreased in comparison to sow-fed, indicating less immune education. In ileum, formula diet induced significant up-regulation of AMCFII, IL-8, IL-15, VEGFA, LIF, FASL, CXCL11, CCL4, CCL25 and down-regulation of IL-6, IL-9, IL-10, IL-27, IFNA4, CSF3, LOC100152038, and LOC100736831 at the transcript level. We have confirmed some of the mRNA data by measuring protein, and significant down-regulation of anti-inflammatory molecule IL-10 in comparison to sow-fed piglets was observed. To further determine the membrane protein expression in the ileum, VE-cadherin, occludin, and claudin-3, Western blot analyses were conducted. Sow fed piglets showed significantly more VE-Cadherin, which associated with levels of calcium, and putrescine measured. It is possible that differences in GI tract and immune development are related to shifts in the microbiome; notably, there were 5-fold higher amounts of Lactobacillaceae spp and 3 fold higher Clostridia spp in the sow fed group in comparison to milk formula-fed piglets, whereas in milk formula-fed pigs Enterobacteriaceae spp was 5-fold higher.

CONCLUSION

In conclusion, formula diet alters GI morphology, microbial abundance, intestinal barrier protein VE-cadherin and anti-inflammatory molecule IL-10 expression. Further characterization of formula effects could lead to modification of infant formula to improve immune function, reduce inflammation and prevent conditions such as allergies and infections.

Organic Solute Transporter α-β Protects Ileal Enterocytes From Bile Acid-Induced Injury

BACKGROUND & AIMS

Ileal bile acid absorption is mediated by uptake via the apical sodium-dependent bile acid transporter (ASBT), and export via the basolateral heteromeric organic solute transporter α-β (OSTα-OSTβ). In this study, we investigated the cytotoxic effects of enterocyte bile acid stasis in Ostα-/- mice, including the temporal relationship between intestinal injury and initiation of the enterohepatic circulation of bile acids.

METHODS

Ileal tissue morphometry, histology, markers of cell proliferation, gene, and protein expression were analyzed in male and female wild-type and Ostα-/- mice at postnatal days 5, 10, 15, 20, and 30. Ostα-/-Asbt-/- mice were generated and analyzed. Bile acid activation of intestinal Nrf2-activated pathways was investigated in Drosophila.

RESULTS

As early as day 5, Ostα-/- mice showed significantly increased ileal weight per length, decreased villus height, and increased epithelial cell proliferation. This correlated with premature expression of the Asbt and induction of bile acid-activated farnesoid X receptor target genes in neonatal Ostα-/- mice. Expression of reduced nicotinamide adenine dinucleotide phosphate oxidase-1 and Nrf2-anti-oxidant responsive genes were increased significantly in neonatal Ostα-/- mice at these postnatal time points. Bile acids also activated Nrf2 in Drosophila enterocytes and enterocyte-specific knockdown of Nrf2 increased sensitivity of flies to bile acid-induced toxicity. Inactivation of the Asbt prevented the changes in ileal morphology and induction of anti-oxidant response genes in Ostα-/- mice.

CONCLUSIONS

Early in postnatal development, loss of Ostα leads to bile acid accumulation, oxidative stress, and a restitution response in ileum. In addition to its essential role in maintaining bile acid homeostasis, Ostα-Ostβ functions to protect the ileal epithelium against bile acid-induced injury. NCBI Gene Expression Omnibus: GSE99579.

Endocrine cells in the ileum of patients with irritable bowel syndrome

AIM

To study the ileal endocrine cell types in irritable bowel syndrome (IBS) patients.

METHODS

Ninety-eight patients with IBS (77 females and 21 males; mean age 35 years, range 18-66 years) were included, of which 35 patients had diarrhea (IBS-D), 31 patients had a mixture of both diarrhea and constipation (IBS-M), and 32 patients had constipation (IBS-C) as the predominant symptoms. The controls were 38 subjects (26 females and 12 males; mean age 40 years, range 18-65 years) who had submitted to colonoscopy for the following reasons: gastrointestinal bleeding, where the source of bleeding was identified as hemorrhoids (n = 24) or angiodysplasia (n = 3), and health worries resulting from a relative being diagnosed with colon carcinoma (n = 11). The patients were asked to complete the: Birmingham IBS symptom questionnaire. Ileal biopsy specimens from all subjects were immunostained using the avidin-biotin-complex method for serotonin, peptide YY (PYY), pancreatic polypeptide (PP), enteroglucagon, and somatostatin cells. The cell densities were quantified by computerized image analysis, using Olympus cellSens imaging software.

RESULTS

The gender and age distributions did not differ significantly between the patients and the controls (P = 0.27 and P = 0.18, respectively). The total score of Birmingham IBS symptom questionnaire was 21 ± 0.8, and the three underlying dimensions: pain, diarrhea, and constipation were 7.2 ± 0.4, 6.6 ± 0.4, and 7.2 ± 0.4, respectively. The density of serotonin cells in the ileum was 40.6 ± 3.6 cells/mm² in the controls, and 11.5 ± 1.2, 10.7 ± 5.6, 10.0 ± 1.9, and 13.9 ± 1.4 cells/mm² in the all IBS patients (IBS-total), IBS-D, IBS-M, and IBS-C patients, respectively. The density in the controls differed significantly from those in the IBS-total, IBS-D, IBS-M, and IBS-C groups (P < 0.0001, P = 0.0001, P = 0.0001, and P < 0.0001, respectively). There was a significant inverse correlation between the serotonin cell density and the pain dimension of Birmingham IBS symptom questionnaire (r = -0.6, P = 0.0002). The density of PYY cells was 26.7 ± 1.6 cells/mm(2) in the controls, and 33.1 ± 1.4, 27.5 ± 1.4, 34.1 ± 2.5, and 41.7 ± 3.1 cells/mm² in the IBS-total, IBS-D, IBS-M, and IBS-C patients, respectively. This density differed significantly between patients with IBS-total and IBS-C and the controls (P = 0.03 and < 0.0001, respectively), but not between controls and, IBS-D, and IBS-M patients (P = 0.8, and P = 0.1, respectively). The density of PYY cells correlated significantly with the degree of constipation as recorded by the Birmingham IBS symptom questionnaire (r = 0.6, P = 0.0002). There were few PP-, enteroglucagon-, and somatostatin-immunoreactive cells in the biopsy material examined, which made it impossible to reliably quantify these cells.

CONCLUSION

The decrease of ileal serotonin cells is associated with the visceral hypersensitivity seen in all IBS subtypes. The increased density of PYY cells in IBS-C might contribute to the constipation experienced by these patients.

Quercetin protects against intestinal barrier disruption and inflammation in acute necrotizing pancreatitis through TLR4/MyD88/p38 MAPK and ERS inhibition

OBJECTIVE

To investigate the effects of quercetin on intestinal barrier disruption and inflammation in acute necrotizing pancreatitis (ANP) in rats, and its possible mechanism.

METHODS

ANP was established by retrograde injection of 3.5% sodium taurocholate into the biliopancreatic duct, and quercetin (50 mg/kg × 3) was administered by intraperitoneal injection prior to and after ANP induction. Pancreatitis was assessed by pancreatic histopathology, plasma amylase, pancreatic myeloperoxidase (MPO) activity, IL-1β, TNFα and IL-6 levels. Injury of the distal ileum was assessed by histological evaluation. The ultrastructural changes of ileal epithelial cells were examined by transmission electron microscope (TEM). Intestinal barrier function was estimated by plasma diamine oxidase (DAO), d-lactate, endotoxin; and intestinal tight junction proteins including zonula occludens-1 (ZO-1), claudin 1, occludin; and bacterial translocation. Intestinal inflammation was determined by IL-1β, TNFα and IL-17 A expression. TLR4, MyD88, pp38 MAPK, and endoplasmic reticulum stress (ERS)-related molecules (Bip, p-IRE1α, sXBP1, p-eIF2α, ATF6) were measured by immunohistochemistry and WB.

RESULTS

Quercetin intervention attenuated pancreatic and ileal pathological damages in ANP (P < 0.05), ameliorated intestinal barrier disruption and inflammation (P < 0.05). Meantime, QE significantly suppressed intestinal TLR4/MyD88/p38 MAPK pathway and ERS activation.

CONCLUSIONS

Quercetin plays a protective role against intestinal barrier disruption and inflammation in ANP, probably partly by inhibiting TLR4/MyD88/p38 MAPK and ERS activation.

Technical considerations and outcomes for ileal ureter replacement: a retrospective study in China

BACKGROUND

Ileal ureter replacement is an alternative treatment for various length ureter defects. We present our experience and outcome of ileal ureter replacement in China.

METHODS

We retrospectively collected data of patients who underwent ileal ureter replacement between January 2010 and January 2015. We reviewed the medical history, indications for surgery, operative data, perioperative data, and outcomes. Besides, follow-up data included symptom, urine routine test, serum creatinine, serum electrolyte status, and radiographic test.

RESULTS

There were 23 patients who underwent ileal ureter replacement by the same surgeon. Twenty patients were performed unilateral ileal ureter replacement, two patients underwent a combination of ileal ureter replacement and Boari flap-psoas hitch, and one received bilateral ileal ureter replacement. Among these patients, the main cause leading to surgical treatment was iatrogenic injuries (n = 15), especially urinary surgery procedure (n = 11). The median follow-up time was 45 months. There were 6 early complications and 6 late complications after operation. Only one patient suffered from small bowel-related complication and was cured by conservative treatment. Only the patient who underwent bilateral ileal ureter replacement had metabolic acidosis. And 22 patients (95.7%) had a good renal function.

CONCLUSIONS

Ileal ureter replacement is an efficacious and safe procedure for the therapy of long ureteral defects. With appropriate technical considerations, the complication rate may decrease.

Inhibition of ileal apical but not basolateral bile acid transport reduces atherosclerosis in apoE⁻/⁻ mice

OBJECTIVE

Interruption of the enterohepatic circulation of bile acids induces hepatic bile acid synthesis, increases hepatic cholesterol demand, and increases clearance of apoB-containing lipoproteins in plasma. Based on these effects, bile acid sequestrants have been used for many years to treat hypercholesterolemia and the associated atherosclerosis. The objective of this study was to determine the effect of blocking ileal apical versus basolateral membrane bile acid transport on the development of hypercholesterolemia and atherosclerosis in mouse models.

METHODS AND RESULTS

ApoE(-/-) and Ldlr(-/-) mice deficient in the apical sodium-dependent bile acid transporter (Asbt) or apoE(-/-) mice deficient in the basolateral bile acid transporter (Ostα) were fed an atherogenic diet for 16 weeks. Bile acid metabolism, cholesterol metabolism, gene expression, and development of atherosclerosis were examined. Mice deficient in Asbt exhibited the classic response to interruption of the enterohepatic circulation of bile acids, including significant reductions in hepatic and plasma cholesterol levels, and reduced aortic cholesteryl ester content. Ileal Fibroblast Growth Factor-15 (FGF15) expression was significantly reduced in Asbt(-/-)apoE(-/-) mice and was inversely correlated with expression of hepatic cholesterol 7-hydroxylase (Cyp7a1). Ileal FGF15 expression was directly correlated with plasma cholesterol levels and aortic cholesterol content. In contrast, plasma and hepatic cholesterol levels and atherosclerosis development were not reduced in apoE(-/-) mice deficient in Ostα.

CONCLUSIONS

Decreases in ileal FGF15, with subsequent increases in hepatic Cyp7a1 expression and bile acid synthesis appear to be necessary for the plasma cholesterol-lowering and atheroprotective effects associated with blocking intestinal bile acid absorption.

Perforated midgut diverticulitis: Revisited

AIM: To study and provide data on the evolution of medical procedures and outcomes of patients suffering from perforated midgut diverticulitis.

METHODS: Three data sources were used: the Medline and Google search engines were searched for case reports on one or more patients treated for perforated midgut diverticulitis (Meckel’s diverticulitis excluded) that were published after 1995. The inclusion criterion was sufficient individual patient data in the article. Both indexed and non-indexed journals were used. Patients treated for perforated midgut diverticulitis at Vestfold Hospital were included in this group. Data on symptoms, laboratory and radiology results, treatment modalities, surgical access, procedures, complications and outcomes were collected. The Norwegian patient registry was searched to find patients operated upon for midgut diverticulitis from 1999 to 2007. The data collected were age, sex, mode of access, surgical procedure performed and number of patients per year. Historical controls were retrieved from an article published in 1995 containing pertinent individual patient data. Statistical analysis was done with SPSS software.

RESULTS: Group I: 106 patients (48 men) were found. Mean age was 72.2 ± 13.1 years (mean ± SD). Age or sex had no impact on outcomes (P = 0.057 and P = 0.771, respectively). Preoperative assessment was plain radiography in 53.3% or computed tomography (CT) in 76.1%. Correct diagnosis was made in 77.1% with CT, 5.6% without (P = 0.001). Duration of symptoms before hospitalization was 3.6 d (range: 1-35 d), but longer duration was not associated with poor outcome (P = 0.748). Eighty-six point eight percent of patients underwent surgery, 92.4% of these through open access where 90.1% had bowel resection. Complications occurred in 19.2% of patients and 16.3% underwent reoperation. Distance from perforation to Treitz ligament was 41.7 ± 28.1 cm. At surgery, no peritonitis was found in 29.7% of patients, local peritonitis in 47.5%, and diffuse peritonitis in 22.8%. Peritonitis grade correlated with the reoperation rate (r = 0.43). Conservatively treated patients had similar hospital length of stay as operated patients (10.6 ± 8.3 d vs 10.7 ± 7.9 d, respectively). Age correlated with hospital stay (r = 0.46). No difference in outcomes for operated or nonoperated patients was found (P = 0.814). Group II: 113 patients (57 men). Mean age 67.6 ± 16.4 years (range: 21-96 years). Mean age for men was 61.3 ± 16.2 years, and 74.7 ± 12.5 years for women (P = 0.001). Number of procedures per year was 11.2 ± 0.9, and bowel resection was performed in 82.3% of patients. Group III: 47 patients (21 men). Patient age was 65.4 ± 14.4 years. Mean age for men was 61.5 ± 17.3 years and 65.3 ± 14.4 years for women. Duration of symptoms before hospitalization was 6.9 d (range: 1-180 d). No patients had a preoperative diagnosis, 97.9% of patients underwent surgery, and 78.3% had multiple diverticula. Bowel resection was performed in 67.4% of patients, and suture closure in 32.6%. Mortality was 23.4%. There was no difference in length of history or its impact on survival between Groups I and III (P = 0.241 and P = 0.198, respectively). Resection was more often performed in Group I (P = 0.01). Mortality was higher in Group III (P = 0.002).

CONCLUSION: In cases with contained perforation, conservative treatment gives satisfactory results, laparoscopy with lavage and drainage can be attempted and continued with a conservative course.

The effects of eupatilin (stillen®) on motility of human lower gastrointestinal tracts

Gastrointestinal motility consists of phasic slow-wave contractions and the migrating motor complex (MMC). Eupatilin (Stillen®) has been widely used to treat gastritis and peptic ulcers, and various cytokines and neuropeptides are thought to be involved, which can affect gastrointestinal motility. We performed a study to identify the effects of eupatilin on lower gastrointestinal motility with electromechanical recordings of smooth muscles in the human ileum and colon. Ileum and colon samples were obtained from patients undergoing bowel resection. The tissues were immediately stored in oxygenated Krebs-Ringer's bicarbonate solution, and conventional microelectrode recordings from muscle cells and tension recordings from muscle strips and ileal or colonic segments were performed. Eupatilin was perfused into the tissue chamber, and changes in membrane potentials and contractions were measured. Hyperpolarization of resting membrane potential (RMP) was observed after administration of eupatilin. The amplitude, AUC, and frequency of tension recordings from circular and longitudinal smooth muscle strips and bowel segments of the ileum and colon were significantly decreased after admission of eupatilin. Eupatilin elicited dose-dependent decreases during segmental tension recordings. In conclusion, eupatilin (Stillen®) showed inhibitory effects on the human ileum and colon. We propose that this drug may be useful for treating diseases that increase bowel motility, but further studies are necessary.

Responses in ileal and cecal bacteria to low and high amylose/amylopectin ratio diets in growing pigs

Dietary starch that escapes digestion in the small intestine may serve as a carbon source for bacterial fermentation in the distal intestine. This study aimed to compare the bacterial community in the ileal and cecal digesta of growing pigs fed diets with low (0.14, LR pigs) and high (0.43, HR pigs) amylose/amylopectin ratio. Pyrosequencing based on MiSeq 2000 platform showed that in ileum digesta, Bacteroidetes of LR pigs was markedly higher than that in HR pigs (P < 0.05). Megasphaera and Prevotella were the two most predominant genera in LR pigs, and Prevotella was significantly higher in LR pigs than in HR pigs (P < 0.05). Prevotella was predominant in cecal samples from both LR and HR pigs, although no significant differences were found between the two groups. In the ileum, Megasphaera elsdenii and Mitsuokella multacida were significantly (P < 0.01) higher in LR pigs along with an increase of acetate and butyrate concentrations. Halomonas pacifica, Escherichia fergusonii, and Actinobacillus minor which belong to class Gammaproteobacteria were significantly lower (P < 0.01) in HR pigs with a significant increase (P < 0.01) of Lactobacillus acetotolerans-like bacteria. Therefore, the changed bacterial community may lead to a transformation of microbial function, such as the alteration of fermentation mode which is showed on the change of microbial metabolites like the concentration of short-chain fatty acids (SCFAs), to a response to the switch of dietary composition, and in turn, to help host absorb and utilize nutrients efficiently. The increase of dietary amylose induced the reduction of conditioned pathogens which may probably be due to the increase of some probiotics such as Lactobacillus, thus reducing the risk of intestinal disease.

Clinical Outcomes of Small Bowel Adenocarcinoma

BACKGROUND

Small bowel adenocarcinomas (SBAs) are rare tumors. Management of SBA is extrapolated from colorectal cancer treatments. Recent evidence suggests that the biology and molecular features of SBA differ from colorectal cancer. The aim of this study was to evaluate the management and outcome of SBA patients. PATIENTS AND METHODS: The National Cancer Data Base (NCDB) was queried for patients with SBA between 2004 and 2013 using ICD-O-3 histology code 8140/3 and topography codes C17.0, C17.1, C17.2, C17.8, and C17.9. Univariate and multivariate survival analyses were conducted to analyze the association between SBA location and overall survival (OS) stratified by stage. Treatment outcomes of surgery, radiation, and systemic therapy were compared.

RESULTS

A total of 7954 SBA patients were identified; duodenum (D) 4607 (57.9%), jejunum (J) 1241 (15.6%), ileum (I) 857 (10.8%), and unspecified 1249 (15.7%). A total of 53.6% patients were male, and 76.6% white. Median age was 66 years. D mostly presented as stage IV disease (37.6%), J as stage II (34.5%) and IV disease (33.8%), and I as stage II (32.2%) and III (30.3%) disease (P < .001). Grade distribution was similar among D, J, and I; the majority were moderately differentiated (40.8%-55.0%), followed by poorly differentiated (30.9%-35.8%) and well differentiated (6.0%-12.4%) (P < .001). D underwent surgery (50.2%) less often than J (90.8%) and I (94.5%) (P < .001). Adjuvant radiation was provided in 8.5% of D, 2.6% of J, and 2.1% of I (P < .001). Adjuvant chemotherapy was provided in 21.9% of D, 50.2% of J, and 42.0% of I (P < .001). The rate of adjuvant chemotherapy was the highest in patients with stage III SBA, and was as follows: D (43.4%), J (65.4%), and I (63.6%) (P < .001). In univariate and multivariate analyses of all patients, adjuvant chemotherapy was associated with improved OS in stage II-III SBA patients. J had the best 5-year OS rate (42.0%; 95% confidence interval, 38.8-45.1, P < .001), and D had the worst (23.0%; 95% confidence interval, 21.6-24.2, P < .001). In multivariate analysis stratified by stage, chemotherapy was associated with improved OS in patients with stage II-IV SBA.

CONCLUSION

Most SBA patients present with stage IV disease. D underwent surgery less often than J and I. Stage II and III D received adjuvant chemotherapy less often compared to stage II and III J and I. Adjuvant chemotherapy was associated with improved OS in patients with stage II-III disease. J had the best 5-year OS rate, and D had the worst.

Ileal antimicrobial peptide expression is dysregulated in old age

In an effort to understand the mechanisms underlying the high prevalence of gastrointestinal tract disorders in old age, we investigated the expression of intestinal antimicrobial peptides in the terminal small intestine of aged mice. Our results show that old mice have reduced transcript levels of ileal α-defensins and lysozyme, two important types of intestinal antimicrobial peptides produced by Paneth cells. In contrast, expression of the C-type lectins Reg3b and Reg3g, as well as β-defensin 1, angiogenin 4 and Relmb, which are made by several epithelial cell types, was significantly upregulated in aged animals suggesting an ongoing response to epithelial distress. Those changes in antimicrobial peptide gene expression associated with histological damage of the ileal epithelium and subtle modifications in the composition of the commensal microbiota. Our findings suggest that dysregulation of antimicrobial peptides expression is a feature of homeostasis disruption in the aged intestine and may contribute to geriatric gastrointestinal dysfunction.

Survival and Metabolic Activity of Pediocin Producer Pediococcus acidilactici UL5: Its Impact on Intestinal Microbiota and Listeria monocytogenes in a Model of the Human Terminal Ileum

Pediococcus acidilactici UL5 is a promising probiotic candidate due to its high survival rate under gastric and duodenal conditions and to its ability to produce the antilisterial bacteriocin pediocin PA-1. Its survival, metabolic activity, and impact on Listeria monocytogenes in a continuous stirred tank reactor containing immobilized human intestinal microbiota were studied over a period of 32 days of feeding a nutrient medium simulating ileal chyme. The impact of P. acidilactici UL5 on different bacterial groups of intestinal origin as well as its survival and its impact on L. monocytogenes were quantified using quantitative polymerase chain reaction coupling with propidium monoazide (PMA-qPCR), which was shown to detect and quantify viable bacteria only. P. acidilactici UL5 and its non-pediocin-producing mutant had no effect on the microbiota, but the producing strain induced an increase in the production of acetic and propionic acids. P. acidilactici survived but appeared to be a poor competitor with intestinal microbiota, dropping by 1.3 and 2.8 log₁₀ after 8 h of fermentation to 10⁴ colony-forming units (cfu) mL^-1. A 1.64 log but non-significant reduction of Listeria was observed when P. acidilactici UL5 was added at 10⁸ cfu mL^-1. P. acidilactici UL5 isolated from the reactor after 3 days was still able to produce the active bacteriocin. These data demonstrate that P. acidilactici UL5 is capable of surviving transit through the ileum without losing its ability to produce pediocin PA-1 but seems to not be enough competitive with the great diversity of organisms found in the ileum.

Distribution of 5-HT3, 5-HT4, and 5-HT7 Receptors Along the Human Colon

Background/Aims

Several disorders of the gastrointestinal tract are associated with abnormal serotonin (5-HT) signaling or metabolism where the 5-HT₃ and 5-HT₄ receptors are clinically relevant. The aim was to examine the distribution of 5-HT₃, 5-HT₄, and 5-HT₇ receptors in the normal human colon and how this is associated with receptor interacting chaperone 3, G protein coupled receptor kinases, and protein LIN-7 homologs to extend previous observations limited to the sigmoid colon or the upper intestine.

Methods

Samples from ascending, transverse, descending, and sigmoid human colon were dissected into 3 separate layers (mucosa, longitudinal, and circular muscles) and ileum samples were dissected into mucosa and muscle layers (n = 20). Complementary DNA was synthesized by reverse transcription from extracted RNA and expression was determined by quantitative or end point polymerase chain reaction.

Results

The 5-HT₃ receptor subunits were found in all tissues throughout the colon and ileum. The A subunit was detected in all samples and the C subunit was expressed at similar levels while the B subunit was expressed at lower levels and less frequently. The 5-HT₃ receptor E subunit was mainly found in the mucosa layers. All splice variants of the 5-HT₄ and 5-HT₇ receptors were expressed throughout the colon although the 5-HT₄ receptor d, g, and i variants were expressed less often.

Conclusions

The major differences in 5-HT receptor distribution within the human colon are in relation to the mucosa and muscular tissue layers where the 5-HT₃ receptor E subunit is predominantly found in the mucosal layer which may be of therapeutic relevance.

Semiautomatic Assessment of the Terminal Ileum and Colon in Patients with Crohn Disease Using MRI (the VIGOR++ Project)

RATIONALE AND OBJECTIVES

The objective of this study was to develop and validate a predictive magnetic resonance imaging (MRI) activity score for ileocolonic Crohn disease activity based on both subjective and semiautomatic MRI features.

MATERIALS AND METHODS

An MRI activity score (the "virtual gastrointestinal tract [VIGOR]" score) was developed from 27 validated magnetic resonance enterography datasets, including subjective radiologist observation of mural T2 signal and semiautomatic measurements of bowel wall thickness, excess volume, and dynamic contrast enhancement (initial slope of increase). A second subjective score was developed based on only radiologist observations. For validation, two observers applied both scores and three existing scores to a prospective dataset of 106 patients (59 women, median age 33) with known Crohn disease, using the endoscopic Crohn's Disease Endoscopic Index of Severity (CDEIS) as a reference standard.

RESULTS

The VIGOR score (17.1 × initial slope of increase + 0.2 × excess volume + 2.3 × mural T2) and other activity scores all had comparable correlation to the CDEIS scores (observer 1: r = 0.58 and 0.59, and observer 2: r = 0.34-0.40 and 0.43-0.51, respectively). The VIGOR score, however, improved interobserver agreement compared to the other activity scores (intraclass correlation coefficient = 0.81 vs 0.44-0.59). A diagnostic accuracy of 80%-81% was seen for the VIGOR score, similar to the other scores.

CONCLUSIONS

The VIGOR score achieves comparable accuracy to conventional MRI activity scores, but with significantly improved reproducibility, favoring its use for disease monitoring and therapy evaluation.

Comparative Analysis of Ileal and Cecal Microbiota in Aged Rats

Background

Gut microbiota contributes to intestinal and immune homeostasis through host-microbiota interactions. Distribution of the gut microbiota differs according to the location in the gastrointestinal tract. Although the microbiota properties change with age, evidence for the regional difference of gut microbiota has been restricted to the young. The aim of this study is to compare the gut microbiota between terminal ileum and cecum of old rats.

Methods

We analyzed gut microbiome of luminal contents from ileum and cecum of 74-week-old and 2-year-old rats (corresponding to 60-year and 80-year-old of human age) by metagenome sequencing of 16S rRNA.

Results

Inter-individual variation (beta diversity) of microbiota was higher in ileum than in cecum. Conversely, alpha diversity of microbiota composition was higher in cecum than in ileum. Lactobacillaceae were more abundant in ileum compared to cecum while Ruminococcaceae and Lachnospiraceae were more enriched in cecum. The proportions of Deltaproteobacteria were increased in cecal microbiota of 2-year-old rats compared to 74-week-old rats.

Conclusions

Major regional distinctions of microbiota between ileum and cecum of old rats appear consistent with those of young rats. Age-related alterations of gut microbiota in old rats seem to occur in minor compositions.

The humoral immune response is essential for successful vaccine protection against paratuberculosis in sheep

Background

The role played by the humoral immune response in animals vaccinated against a mycobacterial disease such as paratuberculosis, is not well understood. Sheep vaccinated against Mycobacterium avium subsp. paratuberculosis (MAP) can still become infected and in some cases succumb to clinical disease. The strength and location of the humoral immune response following vaccination could contribute to the ability of sheep to clear MAP infection. We examined the peripheral antibody response along with the localised humoral response at the site of paratuberculosis infection, the ileum, to better understand how this contributes to MAP infection of sheep following vaccination and exposure.

Results

Through assessing MAP specific serum IgG1 and IgG levels we show that the timing and strength of the humoral immune response directly relates to prevention of infection following vaccination. Vaccinated sheep that subsequently became infected had significantly reduced levels of MAP specific serum IgG1 early after vaccination. In contrast, vaccinated sheep that did not subsequently become infected had significantly elevated MAP specific serum IgG1 following vaccination. Furthermore, at 12 months post MAP exposure, vaccinated and subsequently uninfected sheep had downregulated expression of genes related to the humoral response in contrast to vaccinated infected sheep where expression levels were upregulated.

Conclusions

The timing and strength of the humoral immune response following vaccination against paratuberculosis in sheep directly relates to subsequent infection status. An initial strong IgG1 response following vaccination was crucial to prevent infection. Additionally, vaccinated uninfected sheep were able to modulate that response following apparent MAP clearance, unlike vaccinated infected animals where there was apparent dysregulation of the humoral response, which is associated with progression to clinical disease.