Mucosal Biopsies Of Patients Research Articles

Exploring the clinical relevance of "Angico Gum": an effective biopolymer for topical protection of oesophageal mucosa in gastroesophageal reflux disease patients.

Angico gum (AG) (Anadenanthera colubrina var. Cebil [Griseb.] Altschul) is utilized by some Brazilian communities to alleviate symptoms from gastroesophageal reflux disease. Here, we aimed to investigate the "in vitro" topical protective capacity of AG on human esophageal mucosa. Biopsies of the distal esophageal mucosa were collected from 35 patients with heartburn (24 non-erosive and 11 with erosive oesophagitis (EE)) and mounted in Üssing chambers. AG was applied topically, followed by exposure with acid solution (pH 2.0 or pH 1.0), where transepithelial electrical resistance (TER) and The transepithelial permeability for fluorescein was assessed. The incubation of the AG labeled with FITC in the esophageal mucosa was localized by fluorescence microscopy. Pretreatment with AG prevented the drop in TER induced by acid solution, as well as significantly decreases the fluorescein permeability in non-erosive patients. The protective effect of AG was sustained for up to 120 min both in biopsies of non-erosive and erosive esophagitis. Confocal microscope images showed mucosal luminal adherence of FITC-labeled AG. AG had a prolonged topical protective effect against acid solution in mucosal biopsies of patients with non-erosive and erosive esophagitis.

Oncostatin M Induces a Pro-inflammatory Phenotype in Intestinal Subepithelial Myofibroblasts.

Oncostatin-M (OSM) is associated with antitumor necrosis factor (anti-TNF)-α resistance in inflammatory bowel disease (IBD) and fibrosis in inflammatory diseases. We studied the expression of OSM and its receptors (OSMR, gp130) on intestinal subepithelial myofibroblasts (SEMFs) and the effect of OSM stimulation on SEMFs. The mRNA and protein expression of OSM, OSMR, gp130, and several fibrotic and chemotactic factors were studied in mucosal biopsies and isolated human intestinal SEMFs of patients with IBD and healthy controls (HCs) and in a model of human intestinal organoids (HIOs). Subepithelial myofibroblasts and HIOs were stimulated with OSM and interleukin (IL)-1α/TNF-α. RNAseq data of mucosal biopsies were also analyzed. Oncostatin-M receptors and gp130 were overexpressed in mucosal biopsies of patients with IBD (P < .05), especially in inflamed segments (P < .05). The expression of OSM, OSMR, and gp130 in SEMFs from HCs was increased after stimulation with IL-1α/TNF-α (P < .001; P < .01; P < .01). The expression of CCL2, CXCL9, CXCL10, and CXCL11 was increased in SEMFs from patients with IBD and HCs after stimulation with OSM in a dose-dependent manner (P < .001; P < .05; P < .001; P < .001) and was further increased after prestimulation with IL-1α/TNF-α (P < .01 vs OSM-alone). Similar results were yielded after stimulation of HIOs (P < .01). Oncostatin-M did not induce the expression of collagen I, III, and fibronectin. Oncostatin-M receptor expression was positively correlated with CCL2, CXCL9, CXCL10, and CXCL11 expression in mucosal biopsies (P < .001; P < .001; P = .045; P = .033). Human SEMFs overexpress OSMR in an inflammatory microenvironment. Oncostatin-M may promote inflammation in IBD via its stimulatory effects on SEMFs, which primarily involve chemoattraction of immune cells to the intestinal mucosa.

Endobronchial mucosal biopsy in patients with suspected pulmonary sarcoidosis

BACKGROUND: Sarcoidosis affects the lung in more than 90% of cases, but also affect any organ of the body. The bronchoscope allows for several different diagnostic samples; however, bronchoscopists often underestimate the value of endobronchial biopsy (EBB) in the histological confirmation of sarcoidosis.METHODS: We included 20 patients having suspected pulmonary sarcoidosis (based on clinical and radiological presentation) and being ≥18 years of age. All included patients were subjected to flexible bronchoscopy. Any abnormal endoscopic findings suggestive of endobronchial sarcoidosis was reported. Bronchoalveolar lavage and endobronchial biopsies were obtained.RESULTS: EBB was positive for characteristic non-caseating granuloma of sarcoidosis in 10 patients with a diagnostic yield of 50%. The pathological yield was statistically correlated with the presence of endobronchial mucosal abnormalities but not with the radiological stage. Bronchoalveolar lavage (BAL) was predominantly lymphocytic in 16 (80%) cases, only in 4 (20%) cases their lavage was neutrophilic. There was no statically significant relationship between differential cell count and the biopsy result. The mean value for CD4/CD8 ratio was 1.24±0.45. There was statically significant relationship between CD4/CD8 count in the BAL and the result of mucosal biopsy. The CD4/CD8 count was higher in positive cases with a mean value of 1.46±0.44.CONCLUSIONS: This study provides circumstantial evidence that endobronchial involvement is common in sarcoidosis and EBB can increase the yield of fiber optic diagnosis of sarcoidosis with high diagnostic ratio in cases with mucosal abnormalities. A normal looking endobronchial mucosa should not stop the bronchoscopists from performing EBB.

P059 Diet controls segmented filamentous bacteria in driving Crohn’s disease-like inflammation in TNFdeltaARE mice

Abstract Background Crohn’s disease (CD)-like inflammation in TNFdeltaARE mice (ARE) mice is triggered by dysbiotic gut microbial communities. Similar to the therapeutic effect of exclusive enteral nutrition in CD, dietary intervention using semi-synthetic experimental diet prevents disease development in ARE mice. The aim of this study is to identify the causal microbial cues responsible for CD-like inflammation and to dissect the protective role of diet in ARE mice. Methods Bacterial communities in ARE and wildtype (WT) mice were profiled by 16S rRNA gene sequencing, FISH and qPCR. Germfree WT and ARE mice were colonized with segmented filamentous bacteria (SFB) from dysbiotic ARE mice. Disease activity, cytokine expression, mucosal immune cell infiltrates as well as Paneth and goblet cells phenotypes were assessed in murine ileal and colonic tissue. To assess the influence of diet on disease development, ARE mice were fed either chow, purified semi-synthetic experimental diet (SED) or fiber-rich diet. Impact of SFB on ileo-colonic inflammation was tested in additional mouse models (XIAP-/- and IL10 -/-). Mucosal biopsies from adult and pediatric IBD patients (N=407) were screened for the presence of human SFB using SFB-specific PCR primers. Results Under specific pathogen-free (SPF) conditions, ARE mice developed CD-like ileal inflammation which correlated strongly with increasing abundance of SFB. Mono-colonization of germfree ARE mice with SFB resulted in severe enterocolitis. Parallel to high tissue levels of TNF and IL-17, SPF-mediated inflammation was associated with neutrophil infiltration and the expansion of IFNγ expressing Th1 cells in the mucosa. Loss of Paneth and goblet cell function allowed SFB to penetrate mucus layers towards the epithelium. SED eradicated SFB and completely abolished inflammation in ARE mice. In contrast, fiber-rich diet partially restored SFB colonization and led to increased levels of inflammatory cytokines. SFB mono-colonization of GF XIAP-/- and IL10 -/- failed to induce inflammation, emphasizing host specificity to the mucosa-adherent SFB. Presence of SFB was confirmed in 12 ileal and 11 colonic mucosal biopsies from IBD patients with active or inactive disease. Conclusion We identified a novel pathogenic role of SFB in driving severe CD-like ileo-colonic inflammation characterized by loss of Paneth and goblet cell functions in ARE mice. Detection of SFB in mucosal biopsies of patients with IBD opens new perspectives about therapeutic strategies targeting SFB-mediated processes. Purified diet antagonized SFB colonization and prevented disease development in ARE mice in contrast to fiber-rich diet, clearly demonstrating the important role of diet in modulating a novel IBD-relevant pathobiont.

P714 Comparison of intestinal microbiota profiles of faecal samples, rectal swabs and mucosal biopsies in patients with Inflammatory Bowel Disease. A multicentre, observational study

Abstract Background Since the gut microbiota is altered in patients with Inflammatory Bowel Disease (IBD), microbiome-based biomarkers may be useful for diagnosing and monitoring of IBD. Currently, endoscopy is the gold standard for diagnosis and monitoring disease activity, which can be a high burden for patients. This study aimed to compare intestinal microbiota profiles between three different sampling methods faecal samples, rectal swabs and colonic mucosal biopsies. This could provide more insight into the microbiota composition in different sample types and might contribute to the development of a less invasive biomarker for diagnosing and monitoring IBD. Methods Patients with IBD (Crohn’s Disease or Ulcerative Colitis) who were scheduled for endoscopy were asked to participate. Prior to bowel preparation, a fecal sample and rectal swab were collected. During colonoscopy, mucosal biopsies were derived 20 cm ab ano. Microbiota composition was analyzed by IS-pro, a PCR technique based on species-specific differences in the 16S-23S interspace region of the bacterial ribosomal DNA. Microbiota profiles of the three different sample types were compared within the same patient (for each patient: fecal sample vs. mucosal biopsy, fecal sample vs. rectal swab, rectal swab vs. mucosal biopsy), and between different patients (for each patient: fecal sample of one patient vs. mucosal biopsies of all patients, fecal sample of one patient vs. rectal swabs of all patients, etcetera). Results A total of 200 patients were included. For each patient, similarity of microbiota composition between two sample types was assessed by calculating the Pearson’s correlation (expressed as R2). R2 values of all patients were combined in boxplots. We found a significantly higher correlation between the microbiota profiles of different sample types within the same patient, than between microbiota profiles of different sample types of different patients (median R2 0.27–0.33 and 0.02–0.03 respectively, Figure 1). However, correlation between different sample types from the same patient was still relatively low. The highest correlation was found between microbiota profiles of faecal samples and rectal swabs (median R2 0.33, ICR 0.17–0.54). On phylum level, the highest correlation was found in the Bacteroidetes phylum (Figure 2). For a global analysis of all versus all samples, we generated a clustered heat map, which confirmed the previous finding that microbiota profiles from faecal samples and rectal swabs were most similar to each other. Conclusion Microbiota composition in different sample types from the same patient were more similar to each other than to profiles from different patients. Microbiota profiles of faecal samples and rectal swabs were most identical.

Complexity of Secretory Chemokines in Human Intestinal Organoid Cultures Ex Vivo.

Complexity of Secretory Chemokines in Human Intestinal Organoid Cultures Ex Vivo.

DUOX2 variants associate with preclinical disturbances in microbiota-immune homeostasis and increased inflammatory bowel disease risk.

A primordial gut-epithelial innate defense response is the release of hydrogen peroxide by dual NADPH oxidase (DUOX). In inflammatory bowel disease (IBD), a condition characterized by an imbalanced gut microbiota-immune homeostasis, DUOX2 isoenzyme is the highest induced gene. Performing multiomic analyses using 2872 human participants of a wellness program, we detected a substantial burden of rare protein-altering DUOX2 gene variants of unknown physiologic significance. We identified a significant association between these rare loss-of-function variants and increased plasma levels of interleukin-17C, which is induced also in mucosal biopsies of patients with IBD. DUOX2-deficient mice replicated increased IL-17C induction in the intestine, with outlier high Il17c expression linked to the mucosal expansion of specific Proteobacteria pathobionts. Integrated microbiota/host gene expression analyses in patients with IBD corroborated IL-17C as a marker for epithelial activation by gram-negative bacteria. Finally, the impact of DUOX2 variants on IL-17C induction provided a rationale for variant stratification in case control studies that substantiated DUOX2 as an IBD risk gene. Thus, our study identifies an association of deleterious DUOX2 variants with a preclinical hallmark of disturbed microbiota-immune homeostasis that appears to precede the manifestation of IBD.

In Esophageal Squamous Cells From Eosinophilic Esophagitis Patients, Th2 Cytokines Increase Eotaxin-3 Secretion Through Effects on Intracellular Calcium and a Non-Gastric Proton Pump

In upper airway cells, T helper 2 cytokines that signal through interleukin-4 (IL-4) receptor-α have been shown to stimulate eotaxin-3 secretion via a nongastric proton pump (ngH+,K+ATPase). To seek novel targets for eosinophilic esophagitis (EoE) treatments, we evaluated ngH+,K+ATPase expression in EoE squamous cells, and explored molecular pathways involved in eotaxin-3 secretion by IL-4 receptor-α signaling. ngH+,K+ATPase expression in EoE cells was evaluated by quantitative real-time polymerase chain reaction and Western blotting. IL-4-stimulated eotaxin-3 secretion was measured by enzyme-linked immunosorbent assay after treatment with omeprazole, SCH 28080 (potassium-competitive acid blocker), ethylene glycol-bis(β-aminoethyl)-N,N,N',N'-tetraacetoxymethyl ester (calcium chelator), 2-aminoethoxydiphenyl borate (inhibitor of endoplasmic reticulum calcium release), verapamil, and diltiazem (L-type calcium channel inhibitors). Intracellular calcium transients were measured by Fluo-4 fluorescence. Key experiments were confirmed in EoE primary cells and in RNA sequencing datasets from mucosal biopsies of patients with EoE and controls. EoE cells expressed ngH+,K+ATPase messenger RNA and protein. Omeprazole and SCH 28080 decreased IL-4-stimulated eotaxin-3 secretion. IL-4 increased intracellular calcium transients, and IL-4-stimulated eotaxin-3 secretion was blocked by ethylene glycol-bis(β-aminoethyl)-N,N,N',N'-tetraacetoxymethyl ester, 2-aminoethoxydiphenyl borate, verapamil, and diltiazem. The combination of omeprazole and verapamil suppressed IL-4-stimulated eotaxin-3 secretion more than either agent alone. EoE biopsies expressed higher ngH+,K+ATPase and exhibited more calcium signaling than controls. EoE cells express a nongastric proton pump that mediates T helper 2 cytokine-stimulated eotaxin-3 secretion. IL-4 induces calcium release from the endoplasmic reticulum and calcium entry via L-type calcium channels, increasing intracellular calcium that contributes to eotaxin-3 secretion by EoE cells. L-type calcium channel inhibitors block T helper 2 cytokine-stimulated eotaxin-3 secretion, suggesting a potential role for these agents in EoE treatment.

Evidence of Duodenal Epithelial Barrier Impairment and Increased Pyroptosis in Patients With Functional Dyspepsia on Confocal Laser Endomicroscopy and "Ex Vivo" Mucosa Analysis.

Duodenal epithelial barrier impairment and immune activation may play a role in the pathogenesis of functional dyspepsia (FD). This study was aimed to evaluate the duodenal epithelium of patients with FD and healthy individuals for detectable microscopic structural abnormalities. This is a prospective study using esophagogastroduodenoscopy enhanced with duodenal confocal laser endomicroscopy (CLE) and mucosal biopsies in patients with FD (n = 16) and healthy controls (n = 18). Blinded CLE images analysis evaluated the density of epithelial gaps (cell extrusion zones), a validated endoscopic measure of the intestinal barrier status. Analyses of the biopsied duodenal mucosa included standard histology, quantification of mucosal immune cells/cytokines, and immunohistochemistry for inflammatory epithelial cell death called pyroptosis. Transepithelial electrical resistance (TEER) was measured using Ussing chambers. Epithelial cell-to-cell adhesion proteins expression was assessed by real-time polymerase chain reaction. Patients with FD had significantly higher epithelial gap density on CLE in the distal duodenum than that of controls (P = 0.002). These mucosal abnormalities corresponded to significant changes in the duodenal biopsy samples of patients with FD, compared with controls, including impaired mucosal integrity by TEER (P = 0.009) and increased number of epithelial cells undergoing pyroptosis (P = 0.04). Reduced TEER inversely correlated with the severity of certain dyspeptic symptoms. Furthermore, patients with FD demonstrated altered duodenal expression of claudin-1 and interleukin-6. No differences in standard histology were found between the groups. This is the first report of duodenal CLE abnormalities in patients with FD, corroborated by biopsy findings of epithelial barrier impairment and increased cell death, implicating that duodenal barrier disruption is a pathogenesis factor in FD and introducing CLE a potential diagnostic biomarker in FD.

Quantitative histology-based classification system for assessment of the intestinal mucosal histological changes in patients with celiac disease.

Background/AimsThe existing histological classifications for the interpretation of small intestinal biopsies are based on qualitative parameters with high intraobserver and interobserver variations. We have developed and propose a quantitative histological classification system for the assessment of intestinal mucosal biopsies.MethodsWe performed a computer-assisted quantitative histological assessment of digital images of duodenal biopsies from 137 controls and 124 patients with celiac disease (CeD) (derivation cohort). From the receiver-operating curve analysis, followed by multivariate and logistic regression analyses, we identified parameters for differentiating control biopsies from those of the patients with CeD. We repeated the quantitative histological analysis in a validation cohort (105 controls and 120 patients with CeD). On the basis of the results, we propose a quantitative histological classification system. The new classification was compared with the existing histological classifications for interobserver and intraobserver agreements by a group of qualified pathologists.ResultsAmong the histological parameters, intraepithelial lymphocyte count of ≥25/100 epithelial cells, adjusted villous height fold change of ≤0.7, and crypt depth-to-villous height ratio of ≥0.5 showed good discriminative power between the mucosal biopsies from the patients with CeD and those from the controls, with 90.3% sensitivity, 93.5% specificity, and 96.2% area under the curve. Among the existing histological classifications, our quantitative histological classification showed the highest intraobserver (69.7%–85.03%) and interobserver (24.6%–71.5%) agreements.ConclusionsQuantitative assessment increases the reliability of the histological assessment of mucosal biopsies in patients with CeD. Such a classification system may be used for clinical trials in patients with CeD.

Molecular Analysis of Transbronchial and Mucosal Biopsies in Patients with CLAD

Purpose Chronic lung allograft dysfunction (CLAD) is a clinical/functional diagnosis that cannot be defined by histology in transbronchial biopsies (TBBs). Moreover, understanding the biology of CLAD is crucial for prevention and potential treatment. We studied gene expression associated with CLAD in TBBs, but also studied mucosal biopsies from the third bronchial bifurcation (3BMBs). Methods 223 highly alveolated TBBs (54 CLAD, 169 no CLAD) and 182 3BMBs (43 CLAD, 139 no CLAD) were collected from 7 centers and processed on microarrays. The top 100 non-overlapping genes associated with a diagnosis of CLAD prior to biopsy were identified, annotated, and used for gene set analysis and gene ontology (GO) biological process analysis. Results The top genes associated with CLAD reflected de-differentiation (expression loss), injury (expression gain), and inflammation in both TBBs and 3BMBs. These associations were stronger in 3BMBs. Pathway analysis using the top genes also suggested parenchymal de-differentiation (e.g. loss of transcriptional regulation and mitochondrial function in TBBs) and inflammatory pathway activation, particularly in 3BMBs (Table 1). Gene sets previously annotated in atrophy-scarring, including immunoglobulin transcripts (plasma cells), were elevated in CLAD in TBBs and 3BMBs, but 3BMBs also showed more inflammation-related changes (e.g. interferon gamma effects). Conclusion Molecular changes associated with CLAD were apparent in TBBs and especially in 3BMBs, and indicate that CLAD is a combination of atrophy/scarring, function loss, and, particularly in 3BMBs, inflammation. Molecular assessment of 3BMBs is a particularly promising opportunity to dissect CLAD biology and potentially gain insight into the BOS variant. ClinicalTrials.gov: NCT02812290

Engineered and wild-type L. lactis promote anti-inflammatory cytokine signalling in inflammatory bowel disease patient's mucosa.

Dysbiosis of intestinal microbiota and aberrant inflammatory responses in gastrointestinal mucosa plays important roles in the development of inflammatory bowel disease (IBD). The purpose of this study was to demonstrate the probiotic activity of Lactococcus lactis and the ability of TNF-α-binding by recombinant L. lactis bearing TNF-α-binding affibodies. Various concentrations of recombinant L. lactis were exposed to TNF-α and its binding measured by ELISA. Mucosal biopsies of patients with active IBD were incubated with various L. lactis strains or E. coli DH5α strain and concentrations of TNF-α, IL-23, and IL-10 in the supernatants determined by ELISA. Recombinant L. lactis, at 1 × 109 and 1 × 108 CFU/mL, bound 22.6% and 18.4%, respectively of TNF-α (p < 0.05). When IBD-mucosa was incubated with any L. lactis strain at 1 × 109 CFU/mL, levels of TNF-α and IL-23 were significantly decreased and that of IL-10 increased relative to that for the sterile culture. Opposite trends were observed with E. coli cultures. Recombinant L. lactis at 1 × 108 CFU/mL bound as much as 62.8% (p = 0.026) of TNF-α in IBD-mucosa supernatants compared with the control strain. L. lactis strains are reported, for the first time, to induce an ex vivo anti-inflammatory cytokine profile in IBD inflamed mucosa. L. lactis could therefore constitute a promising alternative approach for treating IBD.

NOT ALL LIP SWELLING IS ANGIOEDEMA

Introduction Cheilitis granulomatosa (CG) is a rare form of recurrent or persistent swelling of one or both lips and one form of orofacial granulomatosis. It is important for allergists to consider the need for mucosal biopsy in patients initially referred for angioedema, especially if the lip swelling has been persistent. Case Description A 35-year-old female presented with 2 months of constant lip swelling. Swelling was worse in the morning with some improvement in the evening although was always present. Early in the course, she was treated with prednisone for one week and antihistamines with initial improvement, but the swelling recurred. Lip swelling was not associated with any tongue swelling, hives, difficulty breathing, or facial paralysis. She had no previous history of angioedema, allergic rhinitis, or asthma. On physical exam, right lower lip was enlarged without any oropharyngeal or tongue swelling. There was mild desquamation of the lips. Patient was initially treated with topical steroids given suspicion for contact dermatitis related to frequent lip balm use. Given persistent symptoms, a lip biopsy was recommended, which was consistent with CG. The patient is now receiving intralesional triamcinolone with improvement of the swelling. Discussion The differential diagnosis for lip swelling is vast. CG along with other granulomatous diseases should be considered when the swelling is persistent with or without associated surface epithelial changes, both of which should not be seen in angioedema of any cause. It is important not to miss this diagnosis due to its association with Crohn's disease.

The Safety of Endoscopic Mucosal Biopsies in Patients Receiving Direct Oral Anticoagulants (DOAC)

The Safety of Endoscopic Mucosal Biopsies in Patients Receiving Direct Oral Anticoagulants (DOAC)

Early Transcriptomic Changes in the Ileal Pouch Provide Insight into the Molecular Pathogenesis of Pouchitis and Ulcerative Colitis.

Ulcerative colitis (UC) only involves the colonic mucosa. Yet, nearly 50% of patients with UC who undergo total proctocolectomy with ileal pouch anal anastomosis develop UC-like inflammation of the ileal pouch (pouchitis). By contrast, patients with familial adenomatous polyposis (FAP) with ileal pouch anal anastomosis develop pouchitis far less frequently. We hypothesized that pathogenic events associated with the development of UC are recapitulated by colonic-metaplastic transcriptomic reprogramming of the UC pouch. We prospectively sampled pouch and prepouch ileum mucosal biopsies in patients with UC with ileal pouch anal anastomosis 4, 8, and 12 months after their pouch was in continuity. Mucosal samples were also obtained from patients with FAP. Transcriptional profiles of the UC and FAP pouch and prepouch ileum were investigated via RNA sequencing and compared with data from a previously published microarray study. Unlike patients with FAP, subjects with UC exhibited a large set of differentially expressed genes between the pouch and prepouch ileum as early as 4 months after pouch functionalization. Functional pathway analysis of differentially expressed genes in the UC pouch revealed an enhanced state of immune/inflammatory response and extracellular matrix remodeling. Moreover, >70% of differentially expressed genes mapped to published inflammatory bowel diseases microarray data sets displayed directional changes consistent with active UC but not with Crohn's disease. The UC pouch, well before histologic inflammation, already displays a systems-level gain of colon-associated genes and loss of ileum-associated genes. Patients with UC exhibit a unique transcriptomic response to ileal pouch creation that can be observed well before disease and may in part explain their susceptibility to the development of pouchitis.

Crohn associated microbial communities associated to colonic mucosal biopsies in patients of the western Mediterranean

Next generation sequencing approaches allow the retrieval of several orders of magnitude larger numbers of amplified single sequences in 16S rRNA diversity surveys than classical methods. However, the sequences are only partial and thus lack sufficient resolution for a reliable identification. The OPU approach used here, based on a tandem combination of high quality 454 sequences (mean >500nuc) applying strict OTU thresholds, and phylogenetic inference based on parsimony additions to preexisting trees, seemed to improve the identification yields at the species and genus levels. A total of thirteen biopsies of Crohn-diagnosed patients (CD) and seven healthy controls (HC) were studied. In most of the cases (73%), sequences were affiliated to known species or genera and distinct microbial patterns could be distinguished among the CD subjects, with a common depletion of Clostridia and either an increased presence of Bacteroidetes (CD1) or an anomalous overrepresentation of Proteobacteria (CD2). Faecalibacterium prausnitzii presence was undetectable in CD, whereas Bacteroides vulgatus–B. dorei characterized HC and some CD groups. Altogether, the results showed that a microbial composition with predominance of Clostridia followed by Bacteroidetes, with F. prausnitzii and B. vulgatus–B. dorei as major key bacteria, characterized what could be considered a balanced structure in HC. The depletion of Clostridia seemed to be a common trait in CD.

PTU-259 Routine biopsy during lower gi endoscopy is of diagnostic value for patients with chronic diarrhoea

<h3>Introduction</h3> Patients investigated for chronic diarrhoea often have normal lower GI endoscopy, and mucosal biopsies are recommended, although their clinical value is controversial. We assessed the diagnostic yield of mucosal biopsies in patients undergoing lower GI endoscopy for investigation of chronic diarrhoea. <h3>Method</h3> All lower GI endoscopies performed in a large multi-site hospital trust over a period of one month for chronic diarrhoea were identified using the endoscopy reporting system and retrospectively analysed. Only procedures where mucosal biopsies were taken were included. The macroscopic endoscopic findings were recorded and correlated with histology findings. <h3>Results</h3> 110 endoscopic procedures were identified. The mean age of patients was 53 (range 19–85), 50% were male. The endoscopic findings were; normal (60%), polyp (s) (17%), colitis/inflammation (8%), polyp (s) and diverticular disease (7%), diverticular disease (6%), tumour (2%). In the group with normal mucosa (n = 65), prevalence of microscopic pathology was 23% (colitis 9.2%, lymphocytic colitis 7.7%, likely drug reaction 3.1%, eosinophilia 1.5%, melanosis coli 1.5%). In the cohort where no polyps were detected, sensitivity for lower GI endoscopy identifying pathology seen on biopsy was 29% (95% CI; 11.4–52.2%), specificity 81% (95% CI; 68.6–89.6%). <h3>Conclusion</h3> Our findings report a prevalence of histological abnormality in patients with chronic diarrhoea and normal lower GI endoscopy that is at the higher end of prevalence reported in other series.^1–5These data support the role of routine biopsy in this group of patients. The practice of routine biopsy in this cohort of patients is further supported by the low sensitivity in identifying abnormalities at endoscopy. The high prevalence of colitis and lymphocytic colitis identified histologically demonstrates the clinical value of biopsy in directly informing treatment decisions. <h3>Disclosure of interest</h3> None Declared. <h3>References</h3> Patel Y, Pettigrew NM, Grahame GR, Bernstein CN. The diagnostic yield of lower endoscopy plus biopsy in nonbloody diarrhea. Gastrointestinal Endosc. 1997;46(4):338–43 Shah RJ, Fenoglio-Preiser C, Bleau BL, Giannella RA. Usefulness of colonoscopy with biopsy in the evaluation of patients with chronic diarrhea. Am J Gastroenterol. 2001;96(4):1091–5 Hotouras A, Collins P, Speake W, Tierney G, Lund JN, Thaha MA. Diagnostic yield and economic implications of endoscopic colonic biopsies in patients with chronic diarrhoea. Colorectal Dis. 2012;14(8):985–8 Sidhu PS, Khan F, Hebden J, Donnelly M. Colonic biopsies to detect microscopic colitis in patients with diarrhoea and “normal” colonoscopy: worth the effort? Gut 2012;<b>61</b>:A372 Yusoff IF, Hoffman NE, Ormonde DG. Is routine mucosal biopsy of value in patients with diarrhoea and normal colonoscopy in an open access setting? <i>Gastrointestinal Endosc.</i>2000:<b>51</b>(4):AB146

HHV-6 antigen and HHV-6 DNA expression in sporadic adenomatous polyps of the colon

Background.Human herpesvirus-6B (HHV-6B) antigens are commonly found in the intestinal mucosa of patients with immunosuppression. In a series of immunocompetent patients with adenomatous, polyp HHV-6B antigen expression from mucosal biopsies was more intense than in biopsies taken from patients receiving immunosuppressive drugs because of kidney transplantation or inflammatory bowel disease. Methods.HHV-6B and cytomegalovirus (CMV) antigen expression was determined from mucosal biopsy samples by immunohistochemistry. HHV-6-DNA content was studied in adenomatous polyps (seven tubular adenomas and one tubulovillous adenoma) taken from eight immunocompetent patients and in three mucosal biopsy samples taken from immunocompetent patients without adenomas using in situ hybridization (ISH) method. Results. HHV-6B antigen expression on mucosal biopsies was strongly positive in five of eight patients with adenomas and negative in all patients without adenoma. CMV antigen expression on mucosal biopsies was faintly positive in three of adenoma patients. HHV-6 ISH was positive in seven of eight adenomatous polyps, most intense in the tubulovillous adenoma and negative in all three mucosal biopsies of patients without adenomas. Conclusion.Intensive HHV-6-DNA expression was found in adenomatous polyps of the colon. Further studies on involvement of HHV-6 in the development of gastrointestinal polyps are warranted.

Aneuploidy-Associated Gene Expression Signatures Characterize Malignant Transformation in Ulcerative Colitis

Malignant transformation in ulcerative colitis (UC) is associated with pronounced chromosomal instability, reflected by aneuploidy. Although aneuploidy can precede primary cancer diagnosis in UC for more than a decade, little is known of its cellular consequences. Whole-genome gene expression analysis was applied to noninflamed colon mucosa, mucosal biopsies of patients with UC, and UC-associated carcinomas (UCCs). DNA image cytometry was used to stratify samples into ploidy types. Differentially expressed genes (DEGs) were analyzed by Ingenuity Pathway Analysis and validated by real-time quantitative PCR. Gene expression changes were more pronounced between normal mucosa and UC (2587 DEGs) than between UC and UCC (827 DEGs). Cytometry identified colitis patients with euploid or aneuploid mucosa biopsies, whereas all UCCs were aneuploid. However, 1749 DEGs distinguished euploid UC and UCCs, whereas only 15 DEGs differentiated aneuploid UC and UCCs. A total of 16 genes were differentially expressed throughout the whole sequence from normal controls to UCCs. Particularly, genes pivotal for chromosome segregation (e.g., SMC3 and NUF2) were differentially regulated along aneuploidy development. The high number of DEGs between normal mucosa and colitis is dominated by inflammatory-associated genes. Subsequent acquisition of aneuploidy leads to subtle but distinct transcriptional alterations, revealing novel target genes that drive genomic instability and thus carcinogenesis. The gene expression signature of malignant phenotypes in aneuploid UC suggests that these lesions might need to be considered as severe as high-grade dysplasia.

Specific histological abnormalities are more likely in biopsies of endoscopically normal large bowel after the age of 60 years

Colonic and rectal biopsies, often taken from an endoscopically normal large bowel, form a significant proportion of the histopathology workload. The aim of this study was to determine diagnostic yield from mucosal biopsies in patients with normal colonoscopy or sigmoidoscopy, and whether or not diarrhoea is predictive of abnormal histology. A retrospective analysis of pathology requests, endoscopy and pathology reports taken during 1 year was undertaken in a tertiary care hospital for all biopsies from endoscopically normal ileal, colonic and rectal mucosa. Of 626 patients fulfilling inclusion criteria, 602 had at least one colonic or rectal biopsy. Colorectal histology was abnormal in 65 (14.5%) of 447 patients with diarrhoea, while of 155 patients without diarrhoea, histology was abnormal in 17 (11%; P=0.41). Patients older than 60 years had a markedly increased likelihood of a specific histological abnormality [odds ratio 2.76 (1.30-5.79); P=0.0045]. Diagnoses included microscopic colitis, distorted mucosal architecture consistent with inflammatory bowel disease, ischaemia, polyps, mucosal prolapse and schistosomiasis. Biopsy of an endoscopically normal large bowel, and of the normal terminal ileum in isolation, yields little abnormal histology. Diarrhoea per se does not identify patients at higher risk of abnormal histology. Increased age, however, does, and mucosal biopsy in the endoscopically normal colon and rectum may be more cost-effective in patients aged more than 60 years.