bluuebunny/crossref_metadata_2025_split huggingface dataset:
A41 LINKING THE APPENDIX MICROBIOME WITH INFLAMMATORY BOWEL DISEASES
Authors: Arjomand Fard N , Armstrong H , Carroll M W , Huynh H Q , Wine E 
Published: March 2021

Abstract

Background
The appendix has been shown to be associated with the pathogenesis and health outcomes in inflammatory bowel diseases (IBD). Specifically, post appendectomy patients are found to be protective for development of ulcerative colitis (UC); however, mechanisms of appendix involvement remain unclear.

Aims
Our aim is to examine the microbes associated with the appendix of IBD patients by identifying changes in microbe abundance and interactions with the host in patient cecum luminal washes, collected from close to the neck of the appendix during colonoscopy. We hypothesize that microbes originating in the appendix of IBD patients, through interactions with host-cells in a disrupted microenvironment in the appendix, could contribute to the pathogenesis of UC.

Methods
Shotgun metagenomics was performed on cecum luminal washes of IBD patients and non-IBD controls. Guided by the metagenomic results, we performed gentamicin protection assays to determine virulence of microbes of interest using Caco2 intestinal epithelial cells. Co-culturing them with human host cells in vitro will identify relevant disease-related factors secreted by microbes and/or host cells using disease models and multiomic approaches.

Results
Shotgun metagenomics results showed that among numerous microbes, several bacterial taxa demonstrated differences in abundance between IBD and non-IBD patients: Flavonifractor, Bacteroide fragilis, and Alistipes represented 8%, 10%, and 21% abundance respectively in non-IBD patients, while in IBD patients they were present below 0.1%. In contrast, Bacteroide vulgatus and Escherichia coli were about 9% and 69% respectively, in IBD patients, whilst they were present at 1.7% and 1.2% in non-IBD patients, respectively. Following our recent method for validating pathobionts (Armstrong, 2019), we used the gentamicin protection assays to assess the ability of these bacteria to invade Caco2 cells, demonstrating a correlation between invasive potential of these microbes and cecal abundance. Mechanistic experiments, aimed at identifying factors impacting invasion, are in progress.

Conclusions
These results provide preliminary, but promising findings suggesting mechanisms by which microbiota possibly originating in the appendix may show altered virulence, which may be related to changes in the appendix microenvironment in IBD. With plans in place to increase our patient cohort we will validate these findings. Identifying and profiling these microbes in IBD patients can help improve the understanding of mechanisms underlying microenvironment changes within the appendix and the gut, which could shed light on the role of the appendix in IBD pathogenesis and clarify how microbes drive inflammation in IBD.

Funding Agencies
CIHR
A44 FATTY ACID COMPOSITION OF THE MEDITERRANEAN DIET PROTECTS AGAINST SPONTANEOUS COLITIS IN THE MUCIN-2 DEFICIENT MURINE MODEL
Authors: Haskey N , Ye J , Barnett J A , Birnie B W , Verdugo Meza A A , Ghosh S , Gibson D L 
Published: March 2021

Abstract

Background
A Mediterranean diet (MD) has been proven efficacious in reducing inflammation in many chronic conditions, mediated by the interaction between diet, the gut microbiota and the immune system. The role of the MD as a dietary management strategy in the management of colitis requires further elucidation. While high fat diets have been shown to result in dysbiosis, our lab has clarified that the type of fat, not total calories derived from fat, predict gut dysbiosis and immunity in murine models of colitis. The n-6 polyunsaturated fatty acids (PUFA) promote colitis, however monounsaturated fatty acids (MUFA) protect against colitis. We hypothesize that a blend of fats, similar to the MD (high MUFA, low n-6 PUFA) will promote gut health beneficial to colitis.

Aims
Using a murine model of chronic intestinal inflammation, the aim of this study was to investigate the effects of dietary fatty acids on colitis by studying dietary fats in isolation from each other, as well as in a fatty acid profile similar to the blend contained in the MD.

Methods
Mice lacking the mucin 2 gene (Muc 2-/-) were weaned on to a 9-week, high fat (41%), isocaloric, isonitrogenous diet where the fat was derived from corn oil, olive oil, milk fat or a MD fat blend (28% MUFA, 8% SFA, 4% n-6 PUFA, 1% n-3 PUFA). The MD fat blend mimicked the fat profile consumed in the human diet. Disease activity, colon histology, cytokines (serum and colonic expression), cecal short chain fatty acids, intestinal permeability, glucose tolerance and gut microbiota (16S rRNA) were analyzed.

Results
Muc 2-/- fed the MD were protected from developing the most severe form of colitis, showing significantly lower disease activity and the absence of rectal prolapse. Histological damage was more severe in the corn oil and milk fat groups which coincided with an increase in infiltrating inflammatory cells and increased mucosal ulcerations. MD and milk fat diets exhibited enhanced intestinal permeability, glucose tolerance, intestinal alkaline phosphatase compared to the corn oil diet. Lower colonic mRNA levels of pro-inflammatory RELM-ß and IL-6 were also seen in the MD and MF diet in comparison to corn oil diet with the milk fat eliciting unique protective immune responses as evidenced by increased expression of IL-22 and Reg3-γ. Differences in alpha-diversity were seen between the MD and milk fat diets, beta-diversity revealed differences in taxa between diet groups.

Conclusions
The fatty acid profile of the MD protects against the development of spontaneous colitis in the Muc2-/- mouse model. In summary, not all dietary fats aggravate colitis, and some may be beneficial during colitis. A diet low in n-6 PUFA and high in MUFA is recommended.

Funding Agencies
CCCCFDR
A45 A NOVEL PH-SENSITIVE OPIOID ANALGESIC THAT SELECTIVELY INHIBITS NOCICEPTION IN DSS-INDUCED COLITIS
Authors: Yu Y , Jiménez-Vargas N N , Tsang Q K , Lopez Lopez C , Jaramillo Polanco J , Stein C , Lomax A E , Reed D E , Bunnett N , Vanner S 
Published: March 2021

Abstract

Background
Opioid drugs are used to treat pain in inflammatory bowel disease (IBD) but their side effects can cause serious morbidity. Therefore, we tested a novel opioid analgesic, ±)-N-(3-fluoro-1-phenethylpiperidine-4-yl)-N-phenylpropionamide (NFEPP) which selectively activates peripheral µ-opioid receptors at acidic pH, as occurs in inflamed tissue.

Aims
Evaluate whether NFEPP causes analgesia in the inflamed colon of DSS-colitis mice using both in vitro and in vivo techniques.

Methods
To measure the visceral motor reflex (VMR) in response to colorectal distention, EMG electrodes connected to a telemetric transmitter were implanted in mice (c57BL/6), after 10 days recovery acute dextran sodium sulfate (DSS) colitis was induced (5 days 2.5% DSS, 2 days water). VMR was measured 30 min after s.c. injection of vehicle or 0.2 mg/kg of NFEPP or fentanyl. Motility was assessed by fecal pellet count 1 hour after NFEPP. Colonic tissue pH was evaluated using the SNARF-4F-5 carboxylic acid probe. Excitability of mouse dorsal root ganglia (DRG) neurons was measured by recording the rheobase (minimum input current to fire an action potential) after superfusion of NFEPP (300 nM, 10 min) or vehicle at pH 6.5 or 7.4. Colonic afferent nerve responses to probing with a von Frey filament (1 gm) were examined before and after exposure to NFEPP (300 nM, 5 min superfusion) at pH 6.5 and 7.4 respectively. The data was analyzed with Welch’s t-test, 1- or 2-way ANOVA with post hoc Dunnett or Bonferroni or Tukey’s test.

Results
NFEPP significantly inhibited the VMR in response to distension in mice with colitis compared to vehicle (decreased response by 65%, P&lt;0.001). NFEPP had no effect in control mice. Conversely, fentanyl caused a similar decreased response in both groups (DSS 79% and control 67%, P&lt;0.001). Pelleting was not affected by NFEPP injection in either group compared to vehicle. The pH measurement revealed a more acidic environment in DSS colonic tissue (ΔpH0.37±0.14, P&lt;0.05) compared to controls. In patch-clamp studies, NFEPP decreased DRG excitability at pH 6.5 compared to the baseline and vehicle (increased rheobase 53.84%, P&lt;0.01 and 36.36%, P&lt;0.05 respectively) but had no effect at pH 7.4. In colonic afferent nerve recordings, NFEPP significantly attenuated afferent responses (28.9% P&lt;0.01) to probing at pH 6.5 but also had no effect at pH 7.4.

Conclusions
This pH-selective opioid agonist significantly inhibits pain at the site of inflammation where the tissue pH is acidic but has no effect in tissues where the pH is in the physiological range. Thus, NFEPP could be an effective opioid analgesic in IBD while being devoid of any unwanted side effects.

Funding Agencies
CCC
A51 ENTERIC PARASITE INFECTION-INDUCED ALTERATION OF THE GUT MICROBIOTA REGULATES INTESTINAL GOBLET CELL BIOLOGY AND MUCIN PRODUCTION VIA TLR2 SIGNALING
Authors: Yousefi Y , Wang H , Haq S , Grondin J , Surette M , Khan W I 
Published: March 2021

Abstract

Background
Goblet cells (GCs) are the major source of mucin which are the main components of the mucus layer that represents the front line of innate defense in the gastrointestinal (GI) tract. Hyperplasia of GCs and increased mucin production are observed in many enteric nematode infections such as Trichuris muris infection. Increased mucin production contributes to parasite clearance by trapping in mucus and inhibiting motility. The GI tract contains trillions of commensal microbes, and these microbes control mucin production from GCs by activating different signaling cascades. During nematode parasite infection due to the coexistence of parasites and microbiota in close proximity of GCs in gut, it is likely that this nematode-microbiota interaction plays an important role in mucin production. Toll-like receptors (TLRs), components of the innate immune system, sense gut microbiota stimuli. The human GC-like cell line, LS174T, expresses TLR2 mRNA which was enhanced by stimulation with synthetic TLR2 ligands. We hypothesize T. muris-induced altered microbiota modulates GC response and mucin production via TLR2 signaling.

Aims
To elucidate the role of T. muris-induced altered gut microbiota in the regulation of intestinal GC response and mucin production via host TLR2 signaling.

Methods
C57BL/6 mice were infected by gavage with ~300 T. muris eggs and infectivity was confirmed by worm burden. Microbiota was analyzed by 16s rRNA sequencing. Colonic GCs response, mucins and TLR2 expression and cytokines production were assessed in germ-free (GF) mice receiving non-infected and T. muris-infected microbiota (collected on day 36 post-infection to exclude worms). Muc2 and Muc5ac expression were assessed in wild-type (WT) and TLR2 deficient (TLR2-/-) mice transplanted with T. muris-infected microbiota following antibiotic treatment.

Results
We observed a difference in microbial composition between non-infected and T. muris infected mice. Transfer of T. muris-infected microbiota into GF mice significantly increased GC numbers and TLR2 expression as well as up-regulated Muc2 and Muc5ac expression and IL-4, IL-13 production compared to GF mice with non-infected microbiota. Antibiotic-treated TLR2-/- mice after receiving microbiota from T. muris-infected mice showed significantly decreased expression of Muc2 and Muc5ac compared to antibiotic-treated WT mice receiving the same microbiota.

Conclusions
T. muris-induced altered microbiota influences intestinal GC response and mucin production via TLR2. In addition to enhancing our understanding on the interaction of parasite with resident microbiota in host defense, this study provides new information on TLR2 based innate signaling in the regulation of GC biology and mucin production.

Funding Agencies
NSERC
A53 STUDYING THE ROLE OF ASCL2 IN THE ESOPHAGEAL EPITHELIUM USING ORGANOIDS
Authors: Hamilton M , Jean D , Giroux V 
Published: March 2021

Abstract

Background
The esophagus is lined with a stratified squamous epithelium that assure protection against the austere environment found in the esophageal lumen. The maintenance of this epithelium is ensured by a rare population of cells: stem cells. Those cells have increased capacity of self-renewal and multipotency, which is the capacity to give rise to every cell types of a tissue. The marker Krt15 was used to identify the first stem cell population in the esophagus. Krt15+ cells display an extended lifespan and they are radioresistant, multipotent and capable of self-renewal. Moreover, it was observed by RNA sequencing that the expression of the transcription factor ASCL2 is strongly increased in Krt15+ cells compared to Krt15- cells. Interestingly, ASCL2 is necessary to maintain the stemness of Lgr5+ intestinal stem cells. It is also a target of the Wnt/β-catenin pathway. The overall goal of this project is to determine the role of ACSL2 in the maintenance of esophageal stem cells and to identify its binding partners since ASCL2 needs to dimerize to efficiently bind DNA.

Aims
Confirm that esophageal organoids are adapted to study ASCL2 in the esophagus.

Methods
Esophageal organoids were established from esophageal epithelial cells from wildtype mice. Following this, organoids were treated with an inhibitor of the Notch pathway (DAPT) to induce hyperplasia or infected with lentiviruses to invalidate Ascl2 (CRISPR/Cas9 approach).

Results
To validate that Ascl2 plays an important role in esophageal cell proliferation, Notch pathway was inhibited through DAPT treatment in esophageal organoids to induce hyperplasia, which was confirmed by increased number of proliferative cells (Ki-67+). ASCL2 protein expression was also increased in DAPT-treated organoids supporting its role in proliferation and confirming that organoid is a good model to study ASCL2 role in esophageal epithelial cells. In this optic, organoids lines invalidated for Ascl2 (CRISPR/Cas9 approach) were established. Our preliminary results suggest that Ascl2 loss affects cell proliferation and organoid size under normal conditions.

Conclusions
The expression of ASCL2 correlates with hyperplasia which supports its role in esophageal epithelium homeostasis.

Funding Agencies
Canada research chair et NSERC
A58 HERPES ZOSTER VIRUS INFECTION IN PEDIATRIC PATIENTS WITH INFLAMMATORY BOWEL DISEASE: SINGLE CENTER EXPERIENCE
Authors: Al-Khuzaei A 
Published: March 2021

Abstract

Background
Patients with IBD receive a variety of medications that modulate the immune response. However, many medications render patients more susceptible to opportunistic infections. Varicella zoster virus (VZV) infection, in particular, has been well reported in IBD patients, mostly in CD. Chickenpox results from primary VZV infection, and is predominantly seen in the pediatric population. Primary prevention via vaccination for VZV, plays an important role in preventing infections in IBD patients before they start immunomodulators, corticosteroid or biologic therapy. Given the advent of zoster vaccines, it is important to determine if IBD patients should be considered for immunization at a younger age.

Aims
1) To document the prevalence of herpes zoster virus (HZV) infection patients with IBD and to further investigate the characteristics of susceptible hosts
2) To assess the severity of herpes zoster in this patient population

Methods
A single center retrospective cohort study was conducted at the Montreal Children’s Hospital. Pediatric IBD patients (age &lt; 18 years) who developed HZV from 2004- 2019 were identified. Data regarding HZV infection, location, severity, treatment, complications and list of all immunosuppressive medications at the time of HZV infection were retrieved as well as data regarding demographics, medical history, vaccination status including Varicella vaccine, and disease behavior.

Results
A total of 9 patients were identified from who had VZV infection or HZV. Eight out of 9 patients, had CD and one patient had UC, and 6 out of 8 CD patients had had extensive disease. The vaccine status was up to date in 6 out of 9 patients, and varicella serology was identified prior to starting steroids or biologic agents.
Eight out of nine patients were on biologics. Eight patients had local disease, skin only, and one patient had systemic disease with HZV meningitis. Four out of 9 patients had their biologic medications either stopped or the next doses were delayed, while other medications including steroids, methotrexate, thiopurines were continued. Five patients were treated with intravenous acyclovir then oral valacyclovir. The rest started on oral valacyclovir and then switched to intravenous acyclovir due to systemic disease. The overall prognosis of the illness was good, and it resulted in full resolution, including the meningitis case.

Conclusions
Our study suggests that being on biologic medication plays a significant role in increasing the chances of reactivation of HZV. Although the severity of the HZV infection in our study is limited to skin involvement, there was one systemic infection. Close attention and mandatory documentation of vaccination status is prudent especially prior to starting immunosuppressive medications. Further studies are needed to determine if these patients should be vaccinated with recombinant zoster vaccine.

Funding Agencies
None
A63 REFINING THE CANADIAN ASSOCIATION OF GASTROENTEROLOGY GUIDELINE ON SCREENING IN PERSONS WITH A FAMILY HISTORY OF NONHEREDITARY COLORECTAL CANCER OR ADENOMA: A MODIFIED DELPHI PROCESS
Authors: Tinmouth J , Paramalingam A , Bellini A , Cotterchio M , Dekker E , Doctorow R , Hassan C , Haddad E , Lofters A , MacIntosh D , Martin J , McCurdy B , Murray I , Naglie H , Paroschy-Harris C , Rabeneck L , Stogios C , Telford J J , Venkatesh R , Wong C , Zenlea T , Dube C 
Published: March 2021

Abstract

Background
In 2018, the Canadian Association of Gastroenterology (CAG) published an extensive systematic review and guideline on screening in persons with a family history (FHx) of nonhereditary colorectal cancer (CRC) and adenoma. While CAG’s recommendations were evidence-based, some recommendations lacked precision (e.g. ranges for some start ages & intervals) and screening cessation age was not addressed, leading to implementation challenges for practitioners and CRC screening programs.

Aims
To review and update the evidence since the 2018 guideline and to formulate implementable recommendations in the Ontario context that are aligned with the CAG guideline.

Methods
ColonCancerCheck (Ontario’s organized CRC screening program) conducted a modified version of the literature search used by CAG (Jan 2017 - Sept 2019). A 19-member expert panel with Canadian and international representatives from endoscopy, primary care, epidemiology, organized CRC screening programs, Ontario’s cancer system and the general public refined the recommendations of the CAG guideline for the purposes of implementation in an organized CRC screening program using a modified Delphi process. This iterative process involved a series of webinars and anonymous survey rounds where the panel reviewed evidence materials and provided online feedback to develop, refine & achieve consensus on screening recommendations in persons with a FHx of CRC/adenoma. Consensus was achieved if ≥75% of members agreed or strongly agreed with the statement.

Results
Six new systematic reviews and 2 new guidelines were identified. New evidence included data on the absolute risk (10 year & lifetime risk) of CRC by type of FHx, as well as the performance of fecal immunochemical testing (FIT) and barriers to CRC screening in persons with a FHx of CRC. The expert panel participated in 3 webinars and 4 online surveys to arrive at consensus. Panel recommendations and level of consensus will be reported for the 6 statements (Table).

Conclusions
Building from the CAG guideline, we derived evidence-based and implementable recommendations for screening persons with a FHx of CRC or adenoma.

Funding Agencies
Ontario Health (Cancer Care Ontario)
A72 NON-INVASIVE PREDICTION OF ESOPHAGEAL VARICES BY TRANSIENT ELASTOGRAPHY AND PLATELET COUNT IN PATIENTS WITH HEPATITIS B AND ADVANCED CHRONIC LIVER DISEASE: VALIDATION OF BAVENO VI AND EXPANDED BAVENO VI CRITERIA
Authors: Zoughlami A , Serero J , Sebastiani G , Deschenes M , Wong P , Khan A Q 
Published: March 2021

Abstract

Background
Patients with compensated advanced chronic liver disease (cACLD) are at higher risk of developing complications from portal hypertension, including esophageal varices (EV). Baveno VI and expanded Baveno VI criteria, based on liver stiffness measurement (LSM) by transient elastography combined with platelet count, have been proposed to avoid unnecessary esophagogastroduodenoscopy (EGD) screening for large esophageal varices needing treatment (EVNT). This approach has not been validated in patients with chronic hepatitis B virus (HBV) infection, who have etiology-specific cut-off of LSM for liver fibrosis.

Aims
We aimed to validate the Baveno VI and expanded Baveno VI criteria for EVNT in HBV patients with cACLD.

Methods
We performed a retrospective analysis of HBV patients who underwent LSM in 2014–2020. Inclusion criteria were: a) diagnosis of cACLD, defined as LSM &gt;9 kPa; b) availability of EGD and platelets within 1 year of LSM. Baveno VI (LSM &lt;20 kPa and platelets &gt;150,000) and expanded Baveno VI criteria (LSM &lt;25 kPa and platelets &gt;110,000) were tested for EGD sparing. Diagnostic performance of these criteria against gold standard (EGD) was computed and compared to patients with hepatitis C virus (HCV) infection and nonalcoholic steatohepatitis (NASH) etiologies, where these criteria have been widely validated. In these patients, the threshold for cACLD definition was &gt;10 kPa.

Results
A total of 287 patients (mean age 56, 95% Child A) were included, comprising of 43 HBV (58% on antiviral therapy), 134 HCV and 110 NASH patients. The prevalence of any grade EV and EVNT was 25% and 8% in the whole cohort, with 19% and 5% in HBV patients, respectively. Table 1 reports diagnostic performance, spared EGD and missed EVNT according to non-invasive criteria and cACLD etiology. Both Baveno VI and expanded Baveno VI criteria performed well in patients with HBV-related cACLD. There was no significant difference on diagnostic performance of these non-invasive criteria across the cACLD etiologies.

Conclusions
These results support use of non-invasive criteria based on LSM and platelets to spare unnecessary EGD in patients with HBV and cACLD. Baveno VI and expanded Baveno VI criteria can improve resource utilization and avoid invasive testing in context of screening EGD for patients with HBV-related cACLD.

Funding Agencies
None