bluuebunny/crossref_metadata_2025_split huggingface dataset:
A183 SECRETIONS OF LACTIC ACID BACTERIA AS ANTI-HELICOBACTER PYLORI AGENTS
Authors: Creuzenet C , Carroll D , Takougoum J M , mohiuddin m , Auger J , McAlister J , Geddes-McAlister J , Bronner S , Binda S 
Published: February 2024

Abstract

Background
Helicobacter pylori (HP) colonizes chronically 50% of the world population, leading to gastric ulcers or cancers in 2-10 % of infections. Due to rising antibiotic resistance, curtailing HP-induced diseases requires the identification of new anti-HP molecules that can reduce HP viability or virulence. Several studies suggest that oral lactic acid bacteria (LAB) supplementation can enhance HP eradication treatment efficacy, suggesting that some LAB produce bioactive molecules with anti-HP properties. We previously found that 18 LAB secrete molecules with activity against two HP strains. The LAB secretions inhibited HP growth and reduced its urease activity, motility and ability to induce the pro-inflammatory cytokine IL-8 from gastric cells. This is important since gastric inflammation is the hallmark of HP infection.

Aims
We aim to elucidate the mechanism of action involved using 5 LAB strains commercialized by Lallemand Health Solutions, including 2 from their Lacidofil® probiotic formulation. Our goal is to harness the potential of the LAB-secreted molecules as novel alternatives to antibiotics or anti-inflammatory agents to curtail HP-induced gastric disease and concentrated cocktails of LAB secretions may synergize with antibiotics.

Methods
This work uses knockout mutagenesis, exposure assays, RNA-Seq, promoter reporter assays and ELISA.

Results
We showed that signals from LAB secretions are transduced by 2 histidine sensor kinases and RNA-Seq analysis was performed on gastric cells and on LAB-exposed HP in stomach-mimicking conditions to identify the pathways that lead to reduced bacterial virulence and reduced inflammation. Also, the effect of LAB on HP adherence to and invasion of gastric cells was investigated, and LAB-specific transcriptional effects are being investigated via luminescence reporter assays. Finally, using metabolomics and proteomics we identified candidate active molecules, which will be validated using commercial compounds and knockout mutagenesis, along with fractionation of the most active LAB secretions

Conclusions
This work highlights the variability between LAB strains and provides mechanistic insights to explain the benefits of well-characterized probiotics such as Lacidofil® in anti-HP treatment or prophylaxis. Adjuvant LAB secretions could benefit the ~6 million patients who develop gastric ulcers or cancers each year worldwide due to HP infection, also saving billions of annual health care costs.

Funding Agencies
CIHRWestern University and MITACS
A185 A GUT MICROBIOME TRANSITION: THE JOURNEY FROM INDIA TO CANADA
Authors: D'Aloisio L D , Haskey N , Abulizi N , Barnett J , Shetty V , Bhaumik U , Ballal M , Ghosh S , Gibson D 
Published: February 2024

Abstract

Background
Young Indian immigrants and Indo-Canadians face a significantly higher risk of inflammatory bowel disease (IBD) in westernized countries. While the etiology of IBD remains unclear, a gut microbiome that is no longer symbiotic with its host is a key player. However, Indians are underrepresented in microbiome research, therefore we cannot accurately assess the role of their gut microbiome in IBD. To understand why Indians are at a greater risk for IBD in Canada, we must first characterize their gut microbiome.

Aims
This study explores how immigration to Canada impacts the gut microbiome of Indian populations, potentially elevating their risk to IBD.

Methods
Stool samples from healthy volunteers (ages 17-53) were collected from Indians in India, Indo-Immigrants, Indo-Canadians, Euro-Canadians and Euro-Immigrants. DNA was extracted for 16S sequencing on the Illumina MiSeq platform and shotgun sequencing on the Illumina NovaSeq platform. Dietary data was processed in ESHA.

Results
Weighted Unifrac revealed distinct clusters of Indian and Indo-Immigrant samples from the westernized cohorts. The most pronounced difference was between Indian and Euro-Canadians with a pseudo-F value of 49.18 (q = 0.00125). Indian versus Indo-Immigrants resulted in a pseudo-F value of 7.707 (q = 0.00125), and Indian versus Indo-Canadian had a pseudo-F value of 15.95 (q = 0.00125). BugBase estimated a significantly higher stress tolerance in the Indian gut, with Proteobacteria driving this phenotypic prediction. Compared to Euro-Canadians, a significantly higher pathogenic potential was predicted in Indians (pFDR= 1.04e-11) and Indo-Immigrants (pFDR= 1.41e-04), driven mainly from Proteobacteria and Bacteroidetes. Multiple comparisons with LDA revealed Prevotella was over 5 times more abundant in Indians residing in India. The gut microbiome in Indians were also enriched with taxa associated with a plant-based diet. Dietary data showed that 59% of Indians do not consume meat, and they also had the lowest consumption (12% caloric intake) of group 4 ultra-processed food (UPF), whereas the highest consumption of UPF was in Indo-Canadians (61% caloric intake) (pbonf ampersand:003C 0.0001). A frequent trend was observed in Indians living in Canada, which was a reduction in key nutrients including soluble fiber, zinc, iron, and folate, some of which are commonly found in plant-based foods.

Conclusions
Overall findings reveal that a loss of Prevotella abundance was observed in Indo-Immigrants and Indo-Canadians, which was associated with a reduction in key nutrients that are common to a plant-based diet, indicating a transition away from their traditional diet. Their dietary changes may be a driver to the displacement of Prevotella and other taxa commonly found in the Indian gut microbiome.

Funding Agencies
NSERC, Killam
A187 PROPHYLACTIC PHAGE TREATMENT ENHANCES SUB-THERAPEUTIC EFFICACY OF BUDESONIDE AGAINST E. COLI DRIVEN COLITIS IN MICE COLONIZED WITH A DEFINED MICROBIOTA
Authors: Jackson K , Galipeau H , Hann A , Bording Jorgensen M , Coombes B , Hosseinidoust Z , Verdu E 
Published: February 2024

Abstract

Background
Patients with IBD are increasingly experiencing treatment failures on frontline therapies. While corticosteroids are an effective frontline intervention, 16% of patients fail to respond, and 20%–30% show only partial responses. Bacteriophages have recently garnered attention as a potential adjunctive therapy for IBD to target bacterial strains associated with IBD, including adherent-invasive Escherichia coli (AIEC).

Aims
Our aim was to determine whether prophylactic bacteriophage therapy could enhance the therapeutic efficacy of a sub-therapeutic dose of budesonide in a gnotobiotic mouse model of E. coli-driven colitis.

Methods
Adult germ-free C57BL/6 mice were co-colonized with altered Schaedler-like flora (ASF) plus E. coli NRG857c, a Crohn’s disease-associated bacterial isolate. Three weeks later, mice were treated with phage HER259 (1x109 PFU/dose; 0.1% bicarbonate) 3 times/ week or vehicle (PBS with 0.1% bicarbonate) 3 times/ week (n=5/group). Mice were then exposed to low-dose dextran sulfate sodium (2%; DSS) in drinking water for 5 days, followed by 2 days of water. All mice were administered a subtherapeutic dosage of 2ug/day of Budesonide halfway through DSS exposure to endpoint. Mice were monitored daily for weight loss, stool consistency, and fecal occult blood. At sacrifice, colon tissue was collected for histological analysis.

Results
Compared with budesonide treatment alone, prophylactic phage treatment, followed by a sub-therapeutic dose of budesonide, led to reduced stool consistency scores (p ampersand:003C0.001) and reduced presence of occult blood (p ampersand:003C 0.001). No difference in fecal E. coli load was observed between groups. At endpoint, the combined phage-budesonide treatment was associated with lower histological scores as compared with mice treated with budesonide alone (p ampersand:003C 0.01).

Conclusions
While underlying mechanisms remain elusive, our results suggest a beneficial effect of prophylactic phage intervention to the subsequent administration of a frontline immunosuppressive compound used to treat IBD. Future work will investigate the mechanisms by which adjunctive phage therapy can enhance existing therapies used to treats colitis, to better inform clinical guidelines.

Funding Agencies
CIHR
A190 HELICOBACTER PYLORI INDUCES AN AUTO-REACTIVE PHENOTYPE IN PINK1 DEFICIENT MICE THAT CORRELATES WITH MOTOR DYSFUNCTION
Authors: Kazanova A , Bessaiah H , Sung J , Gavino C , Pei J , Recinto S , Miller W , Burns L , Zhu L , Stratton J , Gruenheid S 
Published: February 2024

Abstract

Background
Parkinson’s disease (PD) is a chronic neurodegenerative disorder. Several genetic predispositions, including the PTEN-induced kinase 1 (PINK1) mutation, have been implicated in early onset family cases. Besides the loss of dopaminergic neurons in the brain, PD patients have a unique immune phenotype that includes increased inflammation, blood serum, brain levels of proinflammatory cytokines, brain infiltration with cytotoxic CD8 T cells, and loss of regulatory T cells (Treg) and their anti-inflammatory phenotype.
The role of the gut microbiota and gastrointestinal infections are increasingly recognized as a cofactor in PD. One of pathogens associated with the risk of PD is Helicobacter pylori. The prevalence of this Gram-negative bacteria in PD patients is higher than in the general population and its eradication in PD patients improves motor function.
Loss of the PD-associated PINK1 alters induced Treg function in vitro. We previously have shown that in PINK1 knock-out (KO) mice, gut infection with Gram-negative bacteria, Citrobacter rodentium, induces mitochondrial antigen presentation (MitAP) to the CD8 T cells that later infiltrate the brain. In this model, PINK1 KO mice develop a Parkinson-like L-DOPA-responsive motor phenotype after four C. rodentium infections.

Aims
Here we aimed to scrutinize potential role of the H. pylori infection in the induction of motor dysfunction and disbalanced immune tolerance in PINK1 KO mice.

Methods
In addition to standard behavioural testing, at 2- and 6-months post-infection we performed a multiplex cytokine analysis of gastric homogenates and spectral flow cytometry of gastric lamina propria, mesenteric lymph nodes, blood, spleen, and brain infiltrating immunocytes. As well as in vitro immunocytes response and function assays to H.pylori exposure in PINK1 KO and wild-type (WT) littermate controls.

Results
We show that infection with H. pylori causes a long-lasting inflammation in the stomach; and local and systemic immune phenotype that remains 6 months post-infection. This phenotype, though present in some WT infected mice, is higher in PINK1 KOs and similarly to PD patients includes a decrease in Treg proportion, FoxP3 downregulation in regulatory T cells, Gata3+ CD4 T cell loss, as well as increase of circulating mitochondrial antigen-specific CD8 T cells. Moreover, the immune phenotype in the H. pylori infected PINK1 KO mice correlates with motor dysfunction and CD8 T cell brain infiltration with no such association seen in the WT mice.

Conclusions
These results provide insight to the gut-immunity-brain axis in the pathogenesis of Parkinson’s disease, and further investigate the role of Gram-negative bacteria in the establishment of immune tolerance-autoreactivity balance.

Funding Agencies
ASAP
A192 'GLYCOCAGED' DRUGS: PHARMACOKINETICS AND TRANSLATIONAL POTENTIAL FOR PEOPLE WITH IBD
Authors: Ma W , Luzentales-Simpson M , Menzies S C , Wang C , Kothandapani J , Haskey N , Gibson D , Brumer H , Sly L M 
Published: February 2024

Abstract

Background
Inflammatory bowel disease (IBD) is characterized by chronic inflammation in the gastrointestinal tract. Despite the alarming global increase in IBD burden with 1 in 121 Canadians affected, no cure exists. Systemic administration of anti-inflammatory drugs like corticosteroids is a front-line therapy for inducing remission. However, these drugs are limited in their application by deleterious off-target side effects. To target the drug to sites of inflammation and reduce systemic uptake, we developed a microbiome-cleavable, glycoconjugate drug delivery system, termed GlycoCage. We have demonstrated that GlycoCaged dexamethasone (Dex, a potent steroid), is effective at reducing inflammation at 10-fold lower doses than its uncaged counterpart in the SHIP-deficient (SHIP-/-) mouse model of CD-like intestinal inflammation.
We hypothesize that GlycoCaged technology can expand the therapeutic window of IBD drugs by lowering effective doses and eliminating side effects.
Aims:
1) Quantify Dex in systemic circulation.
2) Assess status of inflammation outside of the gut in SHIP-/- mice treated with caged Dex.
3) Measure decaging activity in people with IBD.

Methods
To compare systemic distribution of Dex to caged Dex, we orally gavaged SHIP+/+ and SHIP-/- mice with 3 mg/kg of Dex or the molar equivalent of caged Dex and collected serum for LC-MS/MS analysis at multiple timepoints post oral gavage. In addition to CD-like ileitis, SHIP-/- mice spontaneously develop enlarged mesenteric lymph nodes (MLNs) and inflamed lungs. After daily treatment of Dex or caged Dex for 2 weeks, MLNs and lungs were collected and analyzed for size and histopathology. We also obtained stool samples from healthy control participants and people with IBD to investigate the prevalence of prodrug-cleaving activity by direct enzymatic activity assay using fluorogenic resorufin as a prodrug proxy. Data from people with IBD were stratified to fecal calprotectin.

Results
Unlike free dexamethasone, caged dexamethasone did not enter systemic circulation or impact inflammation outside of the gut in SHIP-/- mice. All people have decaging activity that is not affected by IBD or the individual’s disease activity.

Conclusions
Our results highlight a novel glycoconjugated prodrug strategy to improve and broaden treatment options for people with IBD. In the future, we will evaluate GlycoCaged Dex in a mouse model of colitis and test the efficacy of other GlycoCaged drugs.

Funding Agencies
CCCGlycoNet
A199 ALKAL2/ALK AXIS PROMOTE PERSISTENT VISCERAL PAIN
Authors: Defaye M , Abdullah N , Svendsen K , Soussi L , Dickemann A , Altier C 
Published: February 2024

Abstract

Background
Long-lasting changes in neural pain circuits precipitate the transition from acute to chronic pain in patients living with inflammatory bowel diseases (IBDs). While significant improvement in IBD therapy has been made to reduce inflammation, a large subset of patients continues to suffer throughout quiescent phases of the disease. Peripheral and central mechanisms contribute to the transition from acute to chronic pain during clinical remission. In the search of new treatments, we previously found that targeting the anaplastic lymphoma kinase (ALK) receptor could have therapeutic value for persistent pain conditions.

Aims
Here we investigated whether ALKAL2 (ALK ligand) /ALK signaling axis regulates chronic visceral pain.

Methods
We used the post-inflammatory dextran sodium sulfate (DSS) mouse model of colitis as a well-established rodent model of chronic visceral pain, in which animals display increased VHS 5 weeks after DSS administration in the absence of inflammation as described in IBD patients. To assess the role of ALKAL2/ALK signalling in chronic visceral pain, we pharmacologically blocked ALK receptor using clinically available compound Lorlatinib in the postcolitis model. Moreover we genetically depleted ALKAL2 in gut-innervating nociceptors that express the heat sensitive transient receptor potential vanilloid type 1 (TRPV1) channel, using shRNA vectorized in cell type specific Adeno-associated Viruses.

Results
We showed that ALKAL2 expression was significatively enhanced in lumbosacral (LS) dorsal root ganglia (DRG) sensory neurons in the post-colitis model. In naïve mice, ALKAL2 administration induced visceral hypersensitivity in an ALK dependant manner. In addition, depletion of ALKAL2 in TRPV1 nociceptors or blocking ALK with the clinically available compound Lorlatinib, reversed visceral hypersensitivity in the post-colitis model. Accordingly, phosphorylation of ALK receptor occurring at the LS of the spinal dorsal horn was reduced.

Conclusions
Overall, these findings provide novel insights into the mechanisms underlying the transition from acute to chronic visceral pain in IBD. Our work could generate a portfolio of clinically available anti-cancer drugs, including Lorlatinib, as novel pain therapeutics. Repurposed ALK inhibitor could facilitate pain management in in individuals with IBD.

Funding Agencies
CIHR
A200 EXPOSURE TO CANNABIS SMOKE IN UTERO AFFECTS THE DEVELOPMENT OF THE ENDOCANNABINOID SYSTEM IN THE GASTROINTESTINAL TRACT
Authors: Ratcliffe E , Sunil M , Podinic T , Kasinska J , Hirota J , Raha S 
Published: February 2024

Abstract

Background
Recreational use of cannabis has been legalized in Canada since 2018. Increasing numbers of women are using cannabis while pregnant, with reported rates ampersand:003E10%. There is a disconnect with societal perceptions, with up to one third of women believing that cannabis is safe for use in pregnancy, but with preclinical and clinical studies demonstrating negative neurodevelopmental outcomes. A key component of gut-brain axis regulation is found in the endocannabinoid system (ECS), of which receptors, ligands and enzymes are extensively distributed throughout the gastrointestinal (GI) tract and are actively involved in GI motility and sensation.

Aims
We tested the hypothesis that exposure to cannabis smoke in utero could influence the expression of ECS components in the developing GI tract.

Methods
We developed a “real world” cannabis smoke inhalation model in which CD-1 pregnant mouse dams were exposed daily to a delta-9-tetrahydrocannabinol (THC)-dominant strain of cannabis in a smoking chamber unit, from embryonic days 6 (E6) to E18. Control mice were placed in a restraining cage and exposed to room air for the equivalent time-period. Dams were sacrificed at E18, fetuses removed and the fetal GI tract (from stomach to distal colon) collected for RNA extraction. Key components of the ECS were investigated by developing a NanoString Custom CodeSet, including receptors (cannabinoid receptors 1 and 2; CB1 and CB2, transient receptor potential vanilloid type 1; TRVP1, GPR55) and enzymes (diacylglycerol lipase; DAGL, fatty acid amide hydrolase; FAAH, monoacylglycerol lipase; MAGL, N-acylphosphatidyletanolamine phospholipase D; NAPE-PLD). Samples (n=per litter; 7 cannabis-exposed and 8 control) were processed in the Farncombe Metagenomics Facility and NanoString data analyzed using nSolver Analysis Software.

Results
We found a significant increase in the expression of ECS receptors in the cannabis-exposed compared to control GI tract at E18, including CB2 (pampersand:003C0.05), TRPV1 (pampersand:003C0.05) and GPR55 (pampersand:003C0.0005). Interestingly, no significant change in mRNA expression was detected for CB1. We also found a significant increase in mRNA encoding the full panel of ECS enzymes, including DAGL (pampersand:003C0.005), FAAH (pampersand:003C0.05), MAGL (pampersand:003C0.05) and NAPE-PLD (pampersand:003C0.005) in cannabis-exposed compared to control GI tract.

Conclusions
In conclusion, we have found a significant increase in mRNA expression in a panel of key ECS receptors and enzymes in the GI tract at a point of maximal exposure to cannabis in utero. Future research will be needed to further characterize potential impacts on postnatal GI development and function.

Funding Agencies
CIHRThe Azrieli Foundation
A201 AORTO-ESOPHAGEAL FISTULA AS A COMPLICATION OF ESOPHAGEAL VARICEAL BANDING
Authors: Al Salmi U , Stallwood C , Khan K 
Published: February 2024

Abstract

Aims
This is the first reported case of bleeding from an aorto-esophageal fistula as a consequence of ischemic esophageal ulceration post esophageal variceal banding.

Methods
A 46-year-old male presented with epigastric pain for one-week, which was not associated with fever, jaundice, or symptoms of GI bleed. He was hemodynamically stable with an unremarkable exam and basic labs. He underwent a CT scan which showed chronic portal vein thrombosis extending from the main portal vein into the superior mesenteric vein and evidence of portal hypertension, along with massive esophageal varices. Anticoagulation was not started due to risk of GI bleed.
Upper endoscopy confirmed the presence of three columns of large esophageal varices in the distal and mid esophagus, the largest was 3 cm in size. There was no stigmata of recent bleeding and no gastric varices. Seven bands were applied. CT abdomen was repeated on the seventh day of admission, showing extension of portal vein thrombosis. As such, the thrombosis team started a low dose of anticoagulation.
(dalteparin 7500 IU). He tolerated it well and showed no signs of bleeding prior to discharge.
The day after discharge, the patient presented again with an episode of melena. Examination was remarkable for tachycardia, hypotension and melena. Hemoglobin was stable. Patient was admitted with impression of upper GI bleed most likely secondary to post banding ulcer. He was started on medical therapy. Anticoagulation was held. Next day, the patient had an episode of hematemesis with large amount of blood and clots. Emergent upper endoscopy showed active bleeding in the distal esophagus. Further examination showed a full-thickness, 7 mm defect in the lower esophagus with fresh red blood emptying from it into the esophagus (Figure 1). Thoracic surgery was consulted and suspected a perforated esophageal ulceration at the site of previous banding, with an aorto-esophageal fistula. Patient deteriorated immediately and passed away. The cause of death was cardiac arrest secondary to acute blood loss anemia.

Results
AEF is a recognized cause of upper GI bleeding with a high mortality rate. While rare, it can occur secondary to ischemic esophageal ulcer post EV banding.

Conclusions
This is the first reported case of an aorto-esophageal fistula as a consequence esophageal variceal band ligation. While extremely rare, this complication should be considered as a potentially fatal complication of variceal banding, especially in the setting of a diseased or previously repaired aorta.