bluuebunny/crossref_metadata_2025_split huggingface dataset:
A36 EFFECT OF FIBRE SUPPLEMENTATION IN CELIAC DISEASE: IMPLICATIONS FOR MUCOSAL HEALING
Authors: Wulczynski M , Blom J , Rueda G H , Pinto-Sanchez M , Constante M , Rahmani S , Murray J , Armstrong D , Galipeau H , Verdu E 
Published: February 2024

Abstract

Background
Celiac disease (CeD) is a T-cell mediated enteropathy driven by gluten in genetically susceptible individuals. Mucosal inflammation persists for years even when treated with a gluten-free diet (GFD). Although patients may be advised to increase dietary fibre, some fibres are poorly tolerated leading, potentially, to suboptimal fibre intake and hampering dietary recommendations.

Aims
Our project aims to investigate whether and how the supplementation of two fibre types with distinct functional profiles affects the recovery of gluten-immunopathology in a mouse model of gluten-sensitivity. We hypothesize that: (1) HylonVII, but not inulin, accelerates mucosal recovery by increasing microbial carbolytic activity and production of short-chain fatty acids (SCFA); (2) fibre intake is decreased in CeD patients, leading to decreased SCFA production.

Methods
NOD-DQ8 mice were immunized to gliadin and then placed on a gluten-containing diet. Three weeks later, mice were returned to GFD supplemented with or without HylonVII or inulin to 15% total fibre, for 6, 10, or 12 weeks. Recovery from gluten-induced pathology was evaluated by counting CD3+ intraepithelial lymphocytes (IELs) in villi tips and measuring villus-to-crypt (V/C) ratios in the small intestine. Adult CeD patients (newly diagnosed n=6 and GFD-treated n=7) and healthy controls (n=5) completed a food frequency questionnaire (Victoria DQES v2) and provided fecal samples for evaluation of SCFA production. Fecal SCFA were measured with targeted single ion monitoring gas-chromatography/mass-spectrometry (Agilent) as markers of fibre metabolism.

Results
In gluten immunized mice, 3 weeks of wheat diet led to increased CD3+ IEL counts and decreased V/C ratios (pampersand:003C0.01), which remained abnormal after 6 weeks of GFD. Mice consuming GFD+inulin, but not HylonVII, normalized CD3+ IELs and V/C ratios, had higher fecal SCFAs (pampersand:003C0.05) (primarily acetate), and a higher carbolytic-proteolytic metabolite ratio (pampersand:003C0.05) compared with mice consuming a GFD alone for six weeks. Only 1/7 patients with CeD on GFD met the minimum recommendation for fibre intake (25 g/day, Health Canada), compared with 5/11 participants on gluten-containing diets. SCFA production was impaired in active but not in treated CeD patients (2563 vs 3744 μg/g, pampersand:003C0.01).

Conclusions
In gluten-immunized NOD-DQ8 mice, GFD+inulin accelerates mucosal recovery, which is associated with increased fecal SCFA. In our pilot clinical data, patients on a GFD did not meet the recommendation for fibre intake although they were capable of metabolizing fibre to produce SCFA that could facilitate mucosal recovery. Together these results suggest that CeD on GFD may benefit from increasing fibre, such as inulin, during the GFD.

Funding Agencies
CIHRCeliac Canada
A37 POSTBIOTIC BACTERIAL MEMBRANE VESICLES FROM B. SUBTILIS DELIVER NOD2 LIGANDS AND PROMOTE IN VITRO WOUND RE-EPITHLIALIZATION THROUGH RIPK2 SIGNALING
Authors: Baerg L , Philpott D , Mahadevan R 
Published: February 2024

Abstract

Background
Bacterial membrane vesicles (MVs) are bilipid nanoparticles secreted as a conserved method of intercellular communication. MVs from Gram-positive bacteria carry diverse bacterial products and represent a unique opportunity in the growing field of postbiotics. This native machinery for mediating microbe-host interactions makes MVs a promising tool for intestinal drug delivery in the context of Crohn’s disease (CD). CD is a chronic inflammatory bowel disease characterized by relapsing inflammation of the digestive tract. CD is associated with (1) loss of function mutations in the host gene encoding the nuclear-binding oligomerization domain 2 (NOD2) pattern recognition receptor and (2) a gut microbiome with reduced capabilities to generate NOD2 stimulating muropeptides from peptidoglycan. Nod2-/- mice have decreased barrier integrity and impaired epithelial restitution upon challenge. However, there are currently no therapeutic strategies targeting NOD2 for CD management.

Aims
The aims of this study were to (1) leverage MVs as a biological system for NOD2 ligand delivery to intestinal epithelial cells and (2) determine the roll of probiotic MVs and bacterial ligand synergy in wound re-epithelialization.

Methods
MVs were purified from B. subtilis through filtration and ultracentrifugation. MVs were characterized through nanoparticle tracking analysis using NanoSight300. WT and NOD2-/- HCT116 cells, a human colorectal carcinoma cell line, were utilized for IL-8 secretion quantification by ELISA, gene expression by qPCR, and in vitro scratch wound assay by Incucyte quantification.

Results
Here, we demonstrate for the first time that MVs from B. subtilis deliver NOD2 ligands in vitro. Treatment with isolated MVs induces IL8 secretion and CXCL1 expression in a NOD2-dependent manner. Furthermore, MVs promote re-epithelialization after in vitro scratch wounding. This effect was completely blunted by the addition of an inhibitor for RIPK2, a downstream transducer required for NOD2 signaling. Through bacterial pathogen-associated molecular patterns (PAMPs) screening, we found that wound re-epithelialization is promoted by PAMP synergy but dependent on RIPK2 signaling.

Conclusions
This work suggests that delivery of muropeptides by probiotic-derived MVs is a promising strategy to promote epithelial regeneration during injury through targeting NOD2. Future directions will work towards validating these findings in human ileal primary cells and murine models of intestinal injury.

Funding Agencies
CIHRMedicine by Design
A38 EXPLORING HOW BOWEL PREPARATION CAN AFFECT INFLAMMATORY BOWEL DISEASE VIA THE GUT MICROBIOTA
Authors: Clayton C , Ng K , Tropini C 
Published: February 2024

Abstract

Background
Inflammatory bowel disease (IBD) is a debilitating disorder that targets the gastrointestinal (GI) tract. Although its causes remain unknown, recent studies have identified changes to the gut microbiota associated with IBD. While most gut bacteria are essential for GI health, pathobionts are bacteria that are prevalent in IBD patients and that can act as pathogens and induce inflammation. IBD patients undergo routine endoscopies which require the administration of laxative-based bowel prep to clear out the luminal contents of the GI for the endoscope. It has been found that after bowel prep some IBD patients experience inflammatory flareups. IBD patients may experience adverse reactions following bowel prep, including increased inflammation, emergency room visits, and medication adjustments. Importantly, bowel prep perturbs the gut microbiota, depleting beneficial microorganisms, while allowing pathobiont strains to thrive, which could be the cause for worsened symptoms post-bowel prep in some patients.

Aims
We hypothesize that the altered intestinal microenvironment during bowel prep causes commensal bacteria depletion and favours osmotolerant pathogenic species that lead to increased inflammation in two systems: 1) in a model disease-causing microorganism, Salmonella enterica 2) in an IBD microbiota.

Methods
To investigate pathogen expansion after bowel prep a Salmonella mouse model was established. Microbiota changes were determined by 16S rRNA sequencing and spot plating. Changes to the gut environment and the mechanism for pathogen colonization were characterized using Salmonella mutants and confocal imaging. To identify changes to the IBD microbiota, a humanized mouse model was established, and microbiota changes were investigated as done in the Salmonella model. IBD-associated pathobiont growth was also characterized in in vitro conditions that were identified in our in vivo model.

Results
We have demonstrated that bowel prep increases GI osmolality and leads to increased Salmonella colonization in the gut and systemic organs following bowel prep unlike mice treated with vehicle, supporting our hypothesis. We then explored the effects of bowel prep in a humanized mouse model of IBD, which showed increased translocation of bacteria from the gut to internal organs post-prep. Additionally, IBD-associated pathobionts were able to grow much greater than commensal strains highlighting that IBD pathobionts can persist in the gut after bowel prep.

Conclusions
Our study highlights that bowel prep disrupts the gut microbiota and the intestinal environment allowing for pathogen colonization and bacterial translocation. Therefore, bacterial translocation could provide mechanistic insight for inflammatory flareups following bowel prep. Ultimately, our research underscores the importance of the gut environment in facilitating pathobiont exacerbation of IBD.

Funding Agencies
CIHR
A40 THE ROLE OF HYPOXIA-INDUCIBLE FACTOR IN CELLULAR METABOLIC ADAPTATION UPON GIARDIA INFECTION
Authors: DeMichele E R , Sosnowski O , Allain T , Buret A G 
Published: February 2024

Abstract

Background
Recent findings have highlighted the integral role of oxygen tension in gastrointestinal (GI) homeostasis. During hypoxia when oxygen supply is limited, mammalian cells utilize the Hypoxia-Inducible Factor (HIF) complex to activate genes that promote cell survival and alter glucose metabolism. The GI system exists in a state of physiologic hypoxia, subject to further alterations by pathogens. Although tissue and blood parasites are known to influence tissue oxygen tension, little is known regarding the modulation of hypoxia and HIF by enteric parasites.

Aims
This project aims to characterize the effect of Giardia duodenalis, a common enteric protozoan that perturbs gastrointestinal function leading to diarrheal disease, on the cellular hypoxic response. We hypothesize that hypoxia-associated genes are activated upon Giardia infection, leading to an adaptive metabolic response with increased glycolytic flux to maintain cellular bioenergetic homeostasis.

Methods
Caco-2 colonic epithelial cells were infected with Giardia isolate GS/M (MOI 10) for 1.5 or 4.5 hours to capture early and peak HIF activation, under normoxic (21% O2) or hypoxic (1%O2, STEMCELL hypoxia incubator) conditions. RNA was extracted for RT-qPCR to assess transcriptional changes of known HIF-target genes. Intracellular metabolite analysis via liquid-chromatography mass-spectrometry (hydrophilic-interaction chromatography method) was performed to assess HIF-mediated metabolic changes in uninfected and Giardia-infected cells (MOI 10) exposed to the hypoxia mimetic DMOG or the HIF inhibitor PX-478.

Results
Under normoxic conditions, genes associated with compensatory cellular stress responses such as VEGFA, ANKRD37, GADD45A, and glycolysis-associated genes HK2, and LDHA are upregulated in Giardia-infected cells in a time-dependent manner (pampersand:003C0.05). Under hypoxic conditions, fewer HIF-target genes are upregulated (e.g., VEGFA, GADD45A, PGK1; pampersand:003C0.05), suggesting Giardia-infected cells behave similarly to uninfected cells with constant HIF activation. Analysis of the Caco-2 intracellular metabolome indicates HIF-dependent changes in amino acid (e.g., glycine, threonine) and nucleic acid (e.g., guanosine, inosine, uracil) metabolism. DMOG treatment altered the production of glycolytic intermediates (e.g., DHAP, PEP), confirming the promotion of glycolytic flux by HIF.

Conclusions
Both cell-stress-related and glucose-metabolism HIF target genes are activated upon Giardia infection. As well, some metabolic changes are dependent on HIF activation. These novel findings indicate Giardia promotes a hypoxic state in human intestinal cells, highlighting a metabolic cell rescue mechanism in response to enteropathogens. Furthermore, understanding the role of hypoxia in enteric parasitic infections will shed light on the potential of HIF as a therapeutic target.

Funding Agencies
Natural Sciences and Engineering Research Council of Canada (NSERC)
A45 ASSESSING THE ROLE OF MICROBIOTA DYSBIOSIS ON INTESTINAL TUFT CELL FUNCTIONS UPON GIARDIA INFECTION
Authors: Sosnowski O , Allain T , McKay D , Buret A G 
Published: February 2024

Abstract

Background
Enteric tuft cells can detect and respond to intestinal parasitic infection by modulating host responses to aid parasite clearance, yet the extent of tuft cell functions upon other infections remains to be elucidated. Previous work in our lab showed that the enteric protozoan parasite Giardia induced tuft and goblet cell hyperplasia, yet Giardia colonization in Pou2f3-/- (tuft cell-deficient) mice was impaired. Not only can Giardia modulate the gut microbiota and lead to microbial dysbiosis, but the microbiota itself can influence Giardia colonization. Interestingly, certain microbiota-derived products can activate tuft cells in the gut. In this study, we investigated the role of microbiota dysbiosis in the crosstalk between Giardia and tuft cells.

Aims
We aim to explore the bidirectional effects between tuft cells and Giardia infection by investigating the role of 1) the host microbiota influenced by the presence or absence of tuft cells in altering Giardia infectivity, and 2) Giardia modified microbiota in contributing to tuft cell activity.

Methods
Fecal matter from 6–8-week-old C57Bl/6 and Pou2f3-/- mice were administered to polyethylene glycol (PEG) treated C57Bl/6 mice via oral gavage for 7 days, followed by gavage with 5x104Giardia muris trophozoites. Duodenal parasite burden was assessed 11 days after infection. Small intestinal (SI) microbiota was collected from 5–7-week-old C57Bl/6 and Pou2f3-/- mice following 11 days of G. muris infection and transplanted into PEG treated C57Bl/6 and Pou2f3-/- recipients. 11 days post-transfer, SI tuft and goblet cell hyperplasia was assessed in recipient mice by immunohistochemistry, and Dclk1, Atoh1, and Muc2 gene expression was quantified by RT-qPCR. Parameters of gut motility were evaluated.

Results
FMT with Pou2f3-/- mouse fecal matter prior to Giardia infection led to improved weight gain during infection compared to FMT from C57Bl/6 mice. Giardia modified microbiota (GMM) did not induce tuft or goblet cell hyperplasia 11 days after transfer. Jejunal Dclk1, Atoh1, and Muc2 were no different after GMM compared to control microbiota (CM) transfer. Ileal Atoh1 or Muc2 were upregulated in mice receiving GMM from C57Bl/6 or Pou2f3-/- mice, respectively. Intestinal transit time and stool water content was altered in mice which received GMM from Pou2f3-/- mice compared to CM.

Conclusions
The resident microbiota in tuft cell deficient mice may in part contribute to limiting Giardia infection. Giardia modified microbiota does not substantially contribute to tuft cell hyperplasia or related gene expression alterations at 11 days after microbiota transfer. The mechanistic contributors to tuft cell hyperplasia during Giardia infection and how a lack of tuft cells can lead to impaired colonization does not appear to be primarily driven by microbiota alterations and remains to be fully defined.

Funding Agencies
NSERC
A46 METABOLIC OUTCOMES 12-MONTHS POST-BARIATRIC SURGERY: SLEEVE VERSUS ROUX-EN-Y GASTRIC BYPASS
Authors: Bharatselvam S , Schwenger K , Ghorbani Y , Fischer S , Jackson T , Okrainec A , Allard J P 
Published: February 2024

Abstract

Background
Obesity and its related comorbidities, such as type 2 diabetes (T2D), hyperlipidemia, cardiovascular disease (CVD), and non-alcoholic fatty liver disease (NAFLD) are on the rise. When lifestyle modifications, such as diet and exercise, are ineffective at producing sustained weight loss and improvements in obesity-related comorbidities, other interventions may be recommended. Bariatric surgery is considered in those who have a body mass index (BMI) over 40 kg/m2 or with comorbid conditions and a BMI between 35-40 kg/m2. Two commonly used procedures within this category of surgery are Roux-en-Y gastric bypass (RYGB), the gold standard for weight loss; and laparoscopic sleeve gastrectomy (LSG). Though both surgeries are effective at inducing weight loss, more information is needed on their comparative effectiveness in improving clinical and biochemical outcomes in patients with T2D, hyperlipidemia, and NAFLD in real-world practice.

Aims
Therefore, our objective was to determine the overall effectiveness of RYGB versus LSG at 12-months post-surgery and specifically assess their responses in those with hyperlipidemia, T2D and NAFLD. We chose to analyze both glucose and lipid parameters along with anthropometric measures as they not only provide insight into improvements in comorbid outcomes of obesity but also little-to-no prospective studies compare all of these outcomes in one study using the same cohort.

Methods
This is a prospective cross-sectional and cohort study of 142 patients who underwent bariatric surgery. Clinical and biochemical data were collected at baseline, prior to surgery and 12-months post-bariatric surgery. A liver biopsy was collected during surgery to diagnose NAFLD. The main outcome was 12-month changes in lipid parameters, mainly total cholesterol, between types of surgery.

Results
107 individuals underwent RYGB (75.4%) and 35 underwent LSG (24.6%). Both groups were similar at baseline except for the higher waist circumference and proportion of males undergoing LSG. At 12-months post-surgery, RYGB versus LSG resulted in a significantly lower BMI (pampersand:003C0.0001), triglycerides (pampersand:003C0.05), total and LDL cholesterol (pampersand:003C0.005). Interestingly, ALT was significantly lower in those who underwent LSG (pampersand:003C0.005). In subgroup analysis for determining the effect of the type of surgery in those with comorbidities of obesity, RYGB was superior at improving lipid-related parameters in those with hyperlipidemia with a significant decrease in total cholesterol -0.48 (-0.84, 0.34) (pampersand:003C0.05) whereas LSG was superior at reducing ALT in those with NAFLD with significant decreases in total cholesterol and LDL.

Conclusions
RYGB leads to greater reductions in BMI and lipid parameters, especially in those with hyperlipidemia, whereas LSG showed greater improvements in liver enzymes in those with NAFLD.

Funding Agencies
CIHR
A48 PARENT-REPORTED HEALTH RELATED QUALITY OF LIFE CARING FOR CHILDREN WITH PEDIATRIC FEEDING DISORDERS IN ALBERTA
Authors: Lang A , Chui A , Cohen J , Steinke V , Moland M , Turner J 
Published: February 2024

Abstract

Background
Children with pediatric feeding disorders (PFD), including those requiring tube feeding, need significant care. Caregiver burden includes time, cost, as well as worry over patient morbidity and mortality (1). This project used a validated health-related quality of life (HRQoL) tool for caregivers of children with PFD: the Feeding/Swallowing Impact Survey (FS-IS). The FS-IS has three subscales related to daily activities, worry, and feeding concerns, scored 1-5 with 5 being the most adverse. Prior studies have shown both the total sub-scale scores and the total score correlate with generic quality of life instruments for pediatric caregivers (2). Data was obtained from a provincial quality improvement initiative, the Alberta Provincial Pediatric Eating and Swallowing (PEAS) Project.

Aims
1. To determine the HRQoL reported by caregivers of children with PFD in Alberta. 2. To determine if tube-feeding is associated with worse reported HRQoL.

Methods
Caregivers receiving feeding and swallowing services in Alberta were offered the opportunity to complete the FS-IS online or by phone at baseline and 12 months later. All demographic data was self-reported.

Results
In total 52 caregivers completed the surveys once and 16 at follow-up. Average baseline FSIS was 3.1 (range 1.2-4.7) and at follow up was 3.0 (range 1.5-4.2). There was no difference between the scores of those completing at both time points (p=0.78). At all time points, only 15% of the cohorts reported scores ≤2. As shown in Table 1, children who were tube-fed were older with a longer duration of PFD symptoms, however, HRQoL scores were not different to children not ever tube-fed.

Conclusions
Caregivers of children with PFD face challenges, which do not abate over time. Surprisingly, in our cohort, this is independent of the need for tube feeding and of the duration of PFD symptoms, although we acknowledge the small sample size of those who were never tube-fed. Longitudinal follow-up studies and strategies to improve quality of life are needed.
* FS-IS Global Score (1=never to 5=almost always)

Funding Agencies
Alberta Health Services Maternal Newborn Child & Youth Strategic Clinical Network
A49 AN UNEXPECTED CASE OF SEVERE PROTEIN-LOSING ENTEROPATHY IN A TODDLER
Authors: Podgorny P , Kortbeek S , Lopushinsky S , Boctor D 
Published: February 2024

Abstract

Background
Protein-losing enteropathies (PLE) are characterized by excess loss of serum proteins into the gastrointestinal tract, resulting in hypoproteinemia, peripheral edema, and related respiratory and cardiac sequelae. PLE should be suspected in patients with hypoproteinemia not explained by protein malnutrition, impaired hepatic protein synthesis, or renal losses, and can occur as a consequence of erosive or non-erosive gastrointestinal diseases, and conditions that alter lymphatic flow.

Aims
To present a case of intestinal malrotation with chronic volvulus presenting as PLE.

Methods
In this report, we describe a pediatric patient presenting with PLE ultimately found to have intestinal malrotation with chronic volvulus.

Results
A healthy 1-year-old male presented with acute non-bloody diarrhea and peripheral edema on a background of recurrent colicky abdominal pain and non-bilious emesis. He had significant electrolyte derangements at presentation including hypokalemia, hyponatremia, hypomagnesemia, and metabolic acidosis, with additional laboratory findings of hypoalbuminemia (11g/L), hypogammaglobulinemia (IgA 0.11g/L, IgG 0.77g/L, IgM 0.28g/L), lymphopenia (0.4x10E9/L), and fat-soluble vitamin deficiency (Vitamin A 0.5umol/L, 25-Hydroxyvitamin D 18.4nmol/L, Vitamin E 6umol/L, INR 1.7). In addition to abdominal imaging, he underwent endoscopic evaluation which did not identify an underlying etiology. As his presentation was consistent with PLE, a high-protein, low-fat diet was initiated. Despite dietary adherence for 16 weeks, the PLE features persisted with ongoing severe hypoalbuminemia (20g/L).
Given a suspicion of intestinal lymphangiectasia, a capsule endoscopy was arranged. In the interim, the patient had recurrence of abdominal pain and emesis prompting a repeat abdominal ultrasound which demonstrated swirling of the mesenteric vessels in the midline. An upper gastrointestinal series identified a short mesenteric root with the duodenojejunal junction and cecum in proximity. Urgent laparotomy confirmed a 720-degree volvulus of the small bowel around the mesenteric root, with an abnormally positioned duodenojejunal flexure and cecum. This was presumed to be chronic given the absence of acute vascular compromise. The patient underwent a Ladd procedure. He had complete resolution of symptoms and PLE features on a liberalized diet.

Conclusions
This report identifies a case of intestinal malrotation with chronic volvulus presenting as PLE, highlighting an atypical presentation of intestinal malrotation outside the neonatal period. Awareness of these atypical presentations is important to facilitate prompt diagnosis and treatment, thereby reducing the rate of complications.

Funding Agencies
None