Lev Lichtenstein

Standard Colonic Lavage Alters the Natural State of Mucosal-Associated Microbiota in the Human Colon

Background & Aims Past studies of the human intestinal microbiota are potentially confounded by the common practice of using bowel-cleansing preparations. We examined if colonic lavage changes the natural state of enteric mucosal-adherent microbes in healthy human subjects. Methods Twelve healthy individuals were divided into three groups; experimental group, control group one, and control group two. Subjects in the experimental group underwent an un-prepped flexible sigmoidoscopy with biopsies. Within two weeks, subjects were given a standard polyethylene glycol-based bowel cleansing preparation followed by a second flexible sigmoidoscopy. Subjects in control group one underwent two un-prepped flexible sigmoidoscopies within one week. Subjects in the second control group underwent an un-prepped flexible sigmoidoscopy followed by a second flexible sigmoidoscopy after a 24-hour clear liquid diet within one week. The mucosa-associated microbial communities from the two procedures in each subject were compared using 16S rRNA gene based terminal restriction fragment length polymorphism (T-RFLP), and library cloning and sequencing. Results Clone library sequencing analysis showed that there were changes in the composition of the mucosa-associated microbiota in subjects after colonic lavage. These changes were not observed in our control groups. Standard bowel preparation altered the diversity of mucosa-associated microbiota. Taxonomic classification did not reveal significant changes at the phylum level, but there were differences observed at the genus level. Conclusion Standard bowel cleansing preparation altered the mucosal-adherent microbiota in all of our subjects, although the degree of change was variable. These findings underscore the importance of considering the confounding effects of bowel preparation when designing experiments exploring the gut microbiota.

Regional differences in colonic mucosa-associated microbiota determine the physiological expression of host heat shock proteins.

Cytoprotective heat shock proteins (Hsps) are critical for intestinal homeostasis and are known to be decreased in inflammatory bowel diseases. Signals responsible for maintenance of Hsp expression are incompletely understood. In this study, we find that Hsp25/27 and Hsp70 protein expressions are differentially regulated along the longitudinal length of the large intestine, being highest in the proximal colon and decreasing to the distal colon. This longitudinal gradient was similar in both conventionally colonized mouse colon as well as biopsies of human proximal and distal colon but was abolished in the colon of germ-free mice, suggesting a role of intestinal microbiota in the Hsp regional expression. Correspondingly, analysis of 16S ribosomal RNA genes of bacteria from each colonic segment indicated increased bacterial richness and diversity in the proximal colon. The mechanism of regulation is transcriptional, as Hsp70 mRNA followed a similar pattern to Hsp70 protein expression. Lysates of mucosa-associated bacteria from the proximal colon stimulated greater Hsp25 and Hsp70 mRNA transcription and subsequent protein expression in intestinal epithelial cells than did lysates from distal colon. In addition, transrectal administration of cecal contents stimulated Hsp25 and Hsp70 expression in the distal colon. Thus host-microbial interactions resulting in differential Hsp expression may have significant implications for the maintenance of intestinal homeostasis and possibly for development of inflammatory diseases of the bowel.

Inducible heat shock protein 70 prevents multifocal flat dysplastic lesions and invasive tumors in an inflammatory model of colon cancer

BACKGROUND Heat shock protein 70 (Hsp70) regulates protein biosynthesis and refolding of denatured proteins. Since Hsp70 participates in recovery from stress injury, we examined the effect of Hsp70 genetic deletion in the azoxymethane (AOM)/dextran sulfate sodium (DSS) model of inflammation and colon cancer. METHODS Hsp70 mutant mice (Hsp70.1(-/-)/70.3(-/-)) and wild-type (WT) littermates received AOM and three cycles of DSS and were killed 24 weeks later. Tumors were graded for histology and immunostained for p53, adenomatous polyposis coli, beta-catenin, cyclooxygenase-2 (Cox-2) and inducible nitric oxide synthase (iNOS) and sequenced for p53 mutations. RESULTS Elevated adenomas developed in 4/10 WT mice with no dysplasia in adjacent mucosa. In contrast, 7/8 Hsp70 knock out (KO) mice developed chronic mucosal inflammation and multifocal areas of flat dysplasia and 4/8 progressed to invasive carcinomas arising in a background of flat dysplastic mucosa. These differences in the incidence of flat dysplasia and invasive cancers were significant (P < 0.05). Nuclear p53 was stronger in Hsp70 KO tumors compared with WT tumors, and sequencing confirmed p53 mutations in 2/5 tumors from Hsp70(-/-) versus 0/5 in WT mice. In Hsp70 WT tumors, beta-catenin was predominantly nuclear, compared with membranous beta-catenin in Hsp70(-/-) tumors, suggesting that Hsp70 regulates beta-catenin in colonic tumorigenesis. Cox-2 and iNOS levels were increased in tumors from Hsp70(-/-) mice compared with Hsp70 WT tumors. CONCLUSIONS Hsp70-deleted mice treated with AOM/DSS develop flat invasive colonic tumors that mimic many histological and molecular features of ulcerative colitis colon cancer. This model will be useful to dissect the role of Hsp70 in inflammatory bowel disease colon cancer.

Sorafenib triggers antiproliferative and pro-apoptotic signals in human esophageal adenocarcinoma cells.

Background and purpose Current therapies offer scant benefit to patients with advanced esophageal adenocarcinoma. We investigated the effects of Sorafenib, a multifunctional kinase inhibitor, on several growth regulatory pathways that control cell growth and survival in SEG-1 cells derived from Barrett’s adenocarcinoma. Methods SEG-1 cells were exposed to acidified medium or taurocholic acid, with and without pre-incubation with Sorafenib. Cyclin D1 and E, c-Myc, and Bcl-2 expression levels as well as STAT3 activations were determined by Western blotting. Cyclin D1 mRNA was measured by real-time PCR. Apoptosis was assessed by TUNEL assay. Results Sorafenib significantly inhibited SEG-1 cell proliferation stimulated by acid or bile acid treatments and reduced cell survival. This drug significantly reduced the up-regulations of cyclin D1, cyclin E, c-Myc, and Bcl-2 as well as the activation of STAT3 in SEG-1 cells. Conclusions These results support a rational basis for future clinical studies to assess the therapeutic benefit of Sorafenib in esophageal adenocarcinoma.

Long-term treatment outcome of patients with gastric vascular ectasia treated with argon plasma coagulation.

Background Gastric vascular ectasia (VE) is an uncommon cause of upper gastrointestinal bleeding. Long-term data on the efficacy of argon plasma coagulation (APC) for the treatment of gastric VE are lacking. Methods We retrospectively identified consecutive patients, between January 2005 and December 2010, treated with APC for an index diagnosis of gastric VE. Clinical and endoscopic features and APC treatment success were recorded. Treatment success was determined by resolution of symptoms and stabilization of the hemoglobin level at 30% above baseline. Results A total of 62 patients [28 (45.2%) male] with a mean age of 72.6±12.8 years, who had undergone 159 upper endoscopies (mean 2.6, range 1–10), including 140 APC sessions (mean 2.3, range 1–10), were identified. The duration of follow-up was 46.9±26.5 months. Treatment success was achieved in 16 (25.8%) patients. Predictors of success included older age, focal pattern, lack of comorbid liver failure or collagen vascular disease, use of antiplatelet or anticoagulant drugs, and lower baseline hemoglobin level. Of the patients, 26 (41.9%) died during follow-up. Conclusion APC is safe and effective for the initial management of gastric VE; however, most patients do not experience long-term resolution of upper gastrointestinal bleeding and anemia.

Butyrate and bioactive proteolytic form of Wnt-5a regulate colonic epithelial proliferation and spatial development

Proliferation and spatial development of colonic epithelial cells are highly regulated along the crypt vertical axis, which, when perturbed, can result in aberrant growth and carcinogenesis. In this study, two key factors were identified that have important and counterbalancing roles regulating these processes: pericrypt myofibroblast-derived Wnt-5a and the microbial metabolite butyrate. Cultured YAMC cell proliferation and heat shock protein induction were analzyed after butryate, conditioned medium with Wnt5a activity, and FrzB containing conditioned medium. In vivo studies to modulate Hsp25 employed intra-colonic wall Hsp25 encoding lentivirus. To silence Wnt-5a in vivo, intra-colonic wall Wnt-5a silencing RNA was used. Wnt-5a, secreted by stromal myofibroblasts of the lower crypt, promotes proliferation through canonical β-catenin activation. Essential to this are two key requirements: (1) proteolytic conversion of the highly insoluble ~40 kD Wnt-5a protein to a soluble 36 mer amino acid peptide that activates epithelial β-catenin and cellular proliferation, and (2) the simultaneous inhibition of butyrate-induced Hsp25 by Wnt-5a which is necessary to arrest the proliferative process in the upper colonic crypt. The interplay and spatial gradients of these factors insures that crypt epithelial cell proliferation and development proceed in an orderly fashion, but with sufficient plasticity to adapt to physiological perturbations including inflammation.

Capsule Endoscopy Crohn's Disease Activity Index (CECDAIic or Niv Score) for the Small Bowel and Colon.

Background and the Study Aim: Crohn’s disease (CD) is a chronic inflammatory disorder defined as a transmural inflammation of the bowel wall, affecting the small and large intestine. The Capsule Endoscopy Crohn’s Disease Activity Index (CECDAI or Niv score) was devised to measure mucosal disease activity. We extended the Niv score to the colon and have a comprehensive view of the whole intestine. Methods: We evaluated 3 parameters of intestinal pathology: A, Inflammation; B, Extent of disease; C, Presence of strictures. The scoring formula is as follows: CEDCAIic=(A1×B1+C1)+(A2×B2+C2)+(A3×B3+C3)+(A4×B4+C4) (1=proximal small bowel, 2=distal small bowel, 3=right colon, 4=left colon). Results: The median CECDAIic score was 15.5 (range, 0 to 42), and the mean±SD score was 17.2±11.5. The CECDAIic scores per patient were similar among the 5 observers. Kendall’s coefficient of concordance was high and significant for almost all the parameters examined except for strictures in the proximal small bowel and distal colon. Nevertheless, the coefficients for the small bowel and for the whole intestine were high, 0.85 and 0.77, P<0.0001, respectively. Conclusions: We established a new score, the CECDAIic of the small-bowel and colonic CD. We offer this easy, user-friendly score for use in randomized controlled trials and in the clinical follow-up of CD patients.

Su1121 Anti-TNF and Anti-Drug Antibodies Levels Predict the Outcomes of Interventions After Loss of Response to Adalimumab and Infliximab

Background: Anti-TNFalpha agents are commonly used for ulcerative colitis (UC) therapy in the event of non-response to conventional strategies or as colon-salvaging therapy. The objectives were to assess the appropriateness of biological therapies for UC patients and to study treatment discontinuation over time, according to appropriateness of treatment, as a measure of outcome. Methods: We selected adult ulcerative colitis patients from the Swiss IBD cohort who had been treated with anti-TNFalpha agents. Appropriateness of the firstline anti-TNFalpha treatment was assessed using detailed criteria developed during the European Panel on the Appropriateness of Therapy for UC. Treatment discontinuation as an outcome was assessed for categories of appropriateness. Results: Appropriateness of the first-line biological treatment was determined in 186 UC patients. For 64% of them, this treatment was considered appropriate. During follow-up, 37% of all patients discontinued biological treatment, 17% specifically because of failure. Time-to-failure of treatment was significantly different among patients on an appropriate biological treatment compared to those for whom the treatment was considered not appropriate (p=0.0007). Discontinuation rate after 2 years was 26% compared to 54% between those two groups. Patients on inappropriate biological treatment were more likely to have severe disease, concomitant steroids and/or immunomodulators. They were also consistently more likely to suffer a failure of efficacy and to stop therapy during follow-up. Conclusion: Appropriateness of first-line anti-TNFalpha therapy results in a greater likelihood of continuing with the therapy. In situations where biological treatment is uncertain or inappropriate, physicians should consider other options instead of prescribing anti-TNFalpha agents.

Correlation of 18F-FDG PET/MRE Metrics with Inflammatory Biomarkers in Patients with Crohn’s Disease: A Pilot Study

Background To investigate the association between 18F-FDG (Fluorodeoxyglucose) PET (positron emission tomography)/MRE (magnetic resonance enterography) metrics with the inflammatory biomarkers fecal calprotectin and C-reactive protein (CRP) in patients with Crohns disease (CD). Methods This prospective pilot study was institutional review board (IRB) approved with informed consent obtained. Consecutive CD patients were referred to 18F-FDG PET/MRE. Patients in whom colonoscopy was performed and CRP and fecal calprotectin levels were measured were included. CRP and fecal calprotectin were regarded as positive for inflammation if they were greater than 0.5 mg/dl and 150 mcg/g, respectively. Correlation of quantitative variables was performed using the Pearsons correlation coefficient. Receiver operating characteristic (ROC) curves were drawn and the area under the curve (AUC) was calculated to evaluate the accuracy of PET and MRE metrics in determining the presence of inflammation evaluated by calprotectin and CRP levels. Results Analysis of 21 patients (16 women and 5 men, 43 ± 18 years) was performed. Magnetic resonance index of activity (MaRIA) score had an AUC of 0.63 associated with fecal calprotectin and CRP. Adding apparent diffusion coefficient (ADC) and metabolic inflammatory volume (MIV) to MaRIA score resulted in an AUC of 0.92 with a cutoff value of 447 resulting in 83% and 100% sensitivity and specificity, respectively. Conclusion The addition of ADC and MIV to the MaRIA score increases the accuracy for discrimination of disease activity in patients with CD. Trial registration number is 2015062.