To determine the role of colonic barrier defects and low-grade inflammation in irritable bowel syndrome (IBS)-like symptoms in quiescent inflammatory bowel disease (IBD).
Caecal biopsies were ...collected from 51 IBS, 49 quiescent IBD (31 Crohn's disease (CD) and 18 ulcerative colitis (UC)) patients and 27 controls. IBS was assessed using the Rome III criteria and the IBS severity score. Epithelial barrier integrity was evaluated by determining the paracellular permeability of biopsies mounted in Ussing chambers and the mRNA expression of tight junction proteins (ZO-1, α-catenin and occludin). Low-grade inflammation was evaluated by counting cells, including intraepithelial lymphocytes (IELs), eosinophils and mast cells, and by determining the mRNA and protein expression of tumour necrosis factor (TNF)-α in biopsies and culture supernatants.
IBS-like symptoms were present in 35.4 and 38% of CD and UC patients, respectively. Paracellular permeability was significantly increased in both quiescent IBD with IBS-like symptoms and IBS compared with quiescent IBD without IBS-like symptoms (p<0.01, respectively) or controls (p<0.01, respectively). Significantly lower expression of ZO-1 and α-catenin was detected in IBS and quiescent IBD with IBS-like symptoms. IELs and TNF-α were significantly increased in quiescent IBD with IBS-like symptoms, but not in IBS.
In quiescent IBD, IBS-like symptoms related to persistent subclinical inflammation associated with increased colonic paracellular permeability. A persistent increase in TNF-α in colonic mucosa may contribute to the epithelial barrier defects associated with abdominal pain in quiescent IBD, but not in IBS. Optimisation of anti-inflammatory therapy may be considered in quiescent IBD with IBS-like symptoms.
Aliment Pharmacol Ther 2010; 32: 1315–1322
Summary
Background Non‐invasive approaches are useful to differentiate simple steatosis from non‐alcoholic steatohepatitis (NASH) in obese and morbidly ...obese patients.
Aim To develop a new scoring system to diagnose definitive NASH.
Methods Preoperative clinical and biological data including serum caspase 3‐generated cytokeratin‐18 fragments (CK18) and surgical liver biopsies were obtained from 464 morbidly obese patients who had undergone bariatric surgery. The cohort was divided into two groups: training group (n = 310) and validation group (n = 154). Definitive NASH was defined according to Kleiner’s classification with a Non‐alcoholic fatty liver disease Activity Score (NAS) ≥5.
Results Alanine aminotransferase (ALT), CK18 fragments and the presence of metabolic syndrome were independent predictors for discriminating patients with NAS ≥5 in the training group. These three parameters were used to carry out a scoring system for the prediction of NAS ≥5. Whereas serum CK18 fragment alone had an area under the receiver operating characteristic (AUROC) curve = 0.74, AUROC curves of the scoring system were 0.88 and 0.83 in the training group and the validation group, respectively.
Conclusion A simple and non‐invasive composite model (the Nice Model) including metabolic syndrome, ALT and CK18 fragments is able to predict accurately a non‐alcoholic fatty liver disease activity score ≥5 in morbidly obese subjects.
The incidence of chronic liver disease is constantly increasing, owing to the obesity epidemic. However, the causes and mechanisms of inflammation-mediated liver damage remain poorly understood. ...Endoplasmic reticulum (ER) stress is an initiator of cell death and inflammatory mechanisms. Although obesity induces ER stress, the interplay between hepatic ER stress, NLRP3 inflammasome activation and hepatocyte death signaling has not yet been explored during the etiology of chronic liver diseases. Steatosis is a common disorder affecting obese patients; moreover, 25% of these patients develop steatohepatitis with an inherent risk for progression to hepatocarcinoma. Increased plasma LPS levels have been detected in the serum of patients with steatohepatitis. We hypothesized that, as a consequence of increased plasma LPS, ER stress could be induced and lead to NLRP3 inflammasome activation and hepatocyte death associated with steatohepatitis progression. In livers from obese mice, administration of LPS or tunicamycin results in IRE1α and PERK activation, leading to the overexpression of CHOP. This, in turn, activates the NLRP3 inflammasome, subsequently initiating hepatocyte pyroptosis (caspase-1, -11, interleukin-1β secretion) and apoptosis (caspase-3, BH3-only proteins). In contrast, the LPS challenge is blocked by the ER stress inhibitor TUDCA, resulting in: CHOP downregulation, reduced caspase-1, caspase-11, caspase-3 activities, lowered interleukin-1β secretion and rescue from cell death. The central role of CHOP in mediating the activation of proinflammatory caspases and cell death was characterized by performing knockdown experiments in primary mouse hepatocytes. Finally, the analysis of human steatohepatitis liver biopsies showed a correlation between the upregulation of inflammasome and ER stress markers, as well as liver injury. We demonstrate here that ER stress leads to hepatic NLRP3 inflammasome pyroptotic death, thus contributing as a novel mechanism of inflammation-mediated liver injury in chronic liver diseases. Inhibition of ER-dependent inflammasome activation and cell death pathways may represent a potential therapeutic approach in chronic liver diseases.
Background
Currently, there are no histological criteria to diagnose irritable bowel syndrome (IBS). Our aims were (i) to examine the distribution of inflammatory cells in the colon of healthy and ...IBS subjects and (ii) to find histological diagnosis criteria for IBS.
Methods
Colonic biopsies were taken from four distinct regions of the colon from 20 controls (HC) and 11 patients with IBS (4 with constipation (IBS‐C) and 7 with diarrhea (IBS‐D) and embedded in paraffin. Macrophages, mast cells, eosinophils, and T lymphocytes were immunostained and positive cells counted.
Key Results
In both HC and IBS patients, global cellularity decreased from the cecum to the rectum (P < .01) which is attributed to reduced number of macrophages (P < .05) and eosinophils (P < .001) but not T cells. Mast cells were reduced in IBS (P < .05) but not in HC, particularly in IBS‐D (P < .05). Results showed higher number of macrophages in the left colon of IBS subjects than HC (P < .05).
Conclusion & Inferences
Here we report a decreasing gradient of immune cells from the cecum to the rectum of the human colon. Although global cellularity cannot be used to distinguish between IBS and HC, closer analysis of macrophages and mast cells may be useful markers to confirm IBS histologically and to differentiate between IBS‐C and IBS‐D when clinical presentation alternates between constipation and diarrhoea. This pilot study remains to be confirmed with greater number of patients.
The diagnosis of irritable bowel syndrome is only based on clinical criteria: To improve diagnosis, we wanted to develop histological markers which can be used by pathologists. Simple immunohistological markers detecting macrophages and mast cells in the gut may be able to improve precision of the diagnosis of patients with IBS. This pilot study remains to be confirmed in a larger cohort of patients to determine its validity and usefulness in a clinical setting.
Recent evidence suggests a role for increased colonic permeability and mucosal mast cell (MC) mediators on symptoms related to the irritable bowel syndrome (IBS). Whether allergic factors (AFs) are ...involved in the pathophysiology of IBS is unclear. We addressed the question of the possible influence of an allergic background on IBS symptoms.
We assessed paracellular permeability, mucosal MCs counts, and spontaneous release of tryptase of colonic biopsy specimens in 34 IBS patients and 15 healthy subjects. The severity of IBS was assessed through self-reported questionnaires. All individuals were tested for the presence of AF, including self-perception of adverse reaction to food, personal and familial history of atopic disease, elevated total or specific immunoglobulin E against food/inhalant antigens, blood eosinophilia, and skin tests.
IBS patients had significant enhanced colonic permeability, higher number of MCs, and spontaneous release of tryptase than healthy subjects. The severity of IBS was significantly correlated with colonic permeability (r=0.48, P=0.004), MCs counts (r=0.36, P=0.03), and tryptase (r=0.48, P=0.01). In 13 IBS patients (38.2%) having at least three AFs, symptoms scores, colonic permeability, MCs counts, and tryptase release by colonic biopsies were significantly higher than in those with less than three AFs. IBS patients with at least three AFs were more prone to diarrhea or alternating symptoms. None AF was found to be predictive of IBS severity.
In IBS patients, the presence of an allergic background correlates with a more severe disease and diarrhea predominance, possibly by enhancing mucosal MC activation and paracellular permeability.
A subset of patients with irritable bowel syndrome (IBS) have an increased number of mast cells (MCs) in the colonic mucosa. Psychological factors are believed to contribute to the course of IBS.
To ...examine associations between fatigue, depression and MCs of the colonic mucosa in IBS.
Colonic biopsies were taken from 50 Rome II IBS patients, 21 healthy controls and 11 depressed/fatigued patients without IBS. The cellularity of the lamina propria was determined as the number of inflammatory cells per high power field (hpf) through a 400x microscope. The Fatigue Impact Scale (FIS) and the short form Beck Depression Inventory (BDI) evaluated the severity of fatigue and depression.
IBS patients had a significant increase in the cellularity of the lamina propria compared with controls or with depressed patients (mean (SD) 94.5 (48-110) vs 68 (58-82) and 78 (87-90) cells per hpf, p = 0.005 and p = 0.05, respectively), in particular of MCs (9.3 (5.6-11.7) vs 4.0 (2.7-6.8) and 4.3 (2.8-7.8) cells per hpf, p = 0.001 and p = 0.005, respectively). Both the FIS and BDI scores were significantly higher in IBS or in depressed patients than in controls (p<0.001). In IBS, the FIS score correlated significantly with the cellularity of the lamina propria (r = 0.51, p<0.0001) and MCs (r = 0.64, p<0.0001). In IBS, the BDI score correlated significantly with MCs (r = 0.29, p = 0.03).
Elevated MCs counts are a key feature of the low-grade inflammatory infiltrate in the caecal mucosa of IBS. Fatigue and depression are associated with mucosal cell counts, in particular MCs, suggesting that psychological factors are associated with the low-grade inflammatory infiltrate in IBS.
Liver ischemia‐reperfusion injury occurring in orthotopic liver transplantation (OLT) may be responsible for early graft failure. Molecular mechanisms underlying initial poor graft function (IPGF) ...have been poorly documented in human. The purpose of this study was to identify the major transcriptional alterations occurring in human livers during OLT. Twenty‐one RNA extracts derived from liver transplant biopsies taken after graft reperfusion were compared with 7 RNA derived from normal control livers. Three hundred seventy‐one genes were significantly modulated and classified in molecular pathways relevant to liver metabolism, inflammatory response, cell proliferation and liver protection. Grafts were then subdivided into two groups based on their peak levels of serum aspartate amino transferase within 72 h after OLT (group 1, non‐IPGF: 14 patients; group 2, IPGF: 7 patients). The two corresponding data sets were compared using a supervised prediction method. A new set of genes able to correctly classify 71% of the patients was defined. These genes were functionally associated with oxidative stress, inflammation and inhibition of cell proliferation. This study provides a comprehensive picture of the transcriptional events associated with human OLT and IPGF. We anticipate that such alterations provide a framework for the elucidation of the molecular mechanisms leading to IPGF.
The transcriptome of livers after graft reperfusion provides a comprehensive picture of the transcriptional events associated with human OLT and identifies patients at risk for initial poor graft function.
Background: Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of colorectal cancer (CRC). There are several potential strategies to target EGFR. However, monoclonal ...antibodies and low molecular weight tyrosine kinase inhibitors are the most advanced in clinical development. The majority of studies so far have merely required EGFRs to be expressed by CRC cells. The detection of EGFR expression is usually performed by immunohistochemistry (IHC) in the primary tumor. There are few data regarding the EGFR status in the corresponding distant metastases. Patients and methods: EGFR status was analyzed by IHC in 80 patients (31 male, 49 female) with CRC (70 colon, 10 rectum) and at least one distant metastatic lesion. Metastatic sites analyzed (n=80) were liver (79 patients) and lung (one patient). Results: EGFR reactivity was similar in the primary tumor and the related metastases. Among the 80 paired primary/metastatic tumors, only five (6.3%) showed discordance in EGFR status: two cases with EGFR expression in the primary tumor but not in the metastasis, and three samples with EGFR expression in the metastasis but not in the primary tumor. Conclusions: Between the paired primary tumors and distant metastatic lesions, 94% of samples had concordant EGFR status when analyzed by IHC.
Abstract Normothermic liver ischemia-reperfusion (I-R) may induce hepatocellular autophagy, apoptosis, and necrosis. The aim of this study was to investigate these three types of cell death in ...normothermic liver I-R in rats. A segmental normothermic ischemia of the liver was induced for 120 minutes. Liver autophagy was evaluated by transmission electron microscopy and LC3 (Light Chain 3) immunohistochemical studies. Liver apoptosis was assessed by FLIVO (FLuorescence in vIVO) and TUNEL (TdT-mediated dUTP nick end labeling) assays. Liver necrosis was determined by optical microscopic examination. Autophagy was increased in ischemic liver lobes at 6 hours after reperfusion, compared with nonischemic lobes. Fluorescence microscopy showed in situ caspase-3 and -7 specific activity to be increased in ischemic liver lobes after 6 hours of reperfusion, compared with nonischemic lobes. Quantitative analysis of apoptotic cells evaluated by the TUNEL method showed a clearly significant increase in ischemic liver lobes at 6 hours after reperfusion, compared with nonischemic lobes. Necrotic cell death was significantly increased in ischemic liver lobes at 6 hours after reperfusion, compared with nonischemic lobes ( P < .005). In conclusion, 120 minutes normothermic liver I-R resulted in increased autophagic, apoptotic and necrotic cell death.
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