bluuebunny/crossref_metadata_2025_split huggingface dataset:
A150 DEVELOPMENT OF MIMETIC MATRICES AS INSTRUCTIVE ORGANOIDS MICROENVIRONMENT FOR THE STUDY OF COLONIC DISEASES
Authors: Bat V , Jones C , Boudreau F , Faucheux N , Perreault N 
Published: February 2024

Abstract

Background
The functional complexity of the colonic epithelium is dependent on its interaction with the microenvironment involving gradients of soluble factors, extracellular matrix (ECM) proteins and stiffness. The influence of dynamic changes in the ECM has been observed in tumours, with variations in protein expression and rigidity. Their biomolecular impacts on epithelial cell behaviour are less studied due to the structural complexity of the matrix. Organoids offers a novel approach for the study of ECM biodynamics, as they require a matrix (Matrigel) to develop. Previous work showed that it is possible to grow organoids in hydrogels other than Matrigel. To evaluate the effect of matrix composition alteration on cancer initiation, we developed biofunctionalized composite hydrogels that mimic the ECM changes (chemical and physical) observed in the BmpR1a-deficient telocytes Foxl1 + (Bmpr1a△Foxl1+) mouse model of colorectal cancer (CRC) initiation.

Aims
The development of mimetic matrices, in association with organoids, would enable us to uncover the impact of matrix deregulation on colonic cells behaviour in pathogenesis process.

Methods
These hydrogels were made of alginate and 8-arm polyethylene glycol- vinyl sulfone (PEG) macromers bearing cysteine residues (CYS) and peptides. Four peptides derived from fibronectin, laminin 111, collagen I and collagen IV were used to mimic the ECM changes in the Bmpr1a△Foxl1+ colon. The grafting of CYS on alginate or peptides on PEG macromers was first characterized by thiol quantification assays. The non-grafted peptides were also analysed by uHPLC. Stiffness of the hydrogels was then determined by dynamic mechanical analysis. Finally, normal mouse organoids were seeded on hydrogels and evaluated for survival by live/dead labeling and proliferation by Alamar blue assays. Matrigel was used as a control.

Results
Chemical characterization revealed that CYS were grafted onto the alginate chain at around 190 μmol/g alginate. The PEG macromers were functionalized with four peptides at concentration varying from 0.25 to 1.5 mM. Rigidity of the hydrogels depends on the concentration of alginate used where lower concentration leads to soft matrix (0.5 kPa, homeostasis) and high concentration produced a stiff matrix (4 kPa, diseased). Organoids seeded in these mimetic composite hydrogels survived and proliferated in comparison to alginate alone.

Conclusions
Our results indicate that we can develop mimetic composite hydrogels where colon organoids can survive and thrive. This is a breakthrough model for defining the roles of ECM mechanical and biochemical stimuli in epithelial behaviour during the initiation and development of CRC.

Funding Agencies
CIHR
A161 IMPACT OF EARLY-ONSET COLORECTAL CANCER ON DISABILITY-ADJUSTED LIFE YEARS IN CANADA: 1990 TO 2019
Authors: Stukalin I , Gupta M , Buhler K , Ma C 
Published: February 2024

Abstract

Background
Colorectal cancer is the third most common malignancy and remains a leading cause of potentially preventable morbidity and mortality. Early-onset colorectal cancer (EOCRC) is a growing public health focus, particularly in North America, where incidence rates have increased over time.

Aims
Recognizing that EOCRC affects patients in the prime of their life, we aimed to estimate the impact of EO-CRC on disability-adjusted life years (DALYs) lost in Canada between 1990 and 2019.

Methods
We used the Global Burden of Diseases (GBD) Study to assess temporal trends in incidence, mortality and DALYs for EOCRC (patients ampersand:003C50 years old) in Canada between 1990 and 2019. Point estimates are available from http://ghdx.healthdata.
org/gbd-results-tool. Rates were estimated per 100 0000 individuals at risk and stratified by age and sex. Annual percentage changes (APC) were estimated using joinpoint regression with 95% confidence intervals (CIs).

Results
In 2019, the incidence, mortality and corresponding DALYs rates for EOCRC were 15.67 (95% CI 11.58, 20.81), 3.19 (95% CI 2.81, 3.61), and 161.88 (95% CI 142.50, 183.53) per 100,000 individuals, respectively. Overall incidence increased significantly during the study period by 1.12%/year (95% CI 0.91%, 1.62%). An analysis of the temporal trends demonstrates that the most significant increase in incidence in EOCRC occurred between 2000 - 2006 with an APC of 3.19% (95% CI 2.40%, 3.99%), which was primarily driven by an increased incidence in men. Mortality (APC 3.30%, 95% CI 2.41%, 4.19%) and DALYs (APC 3.28%, 95% CI 2.34%, 4.22%) for EOCRC also significantly increased for males between 2001 - 2006.

Conclusions
Our study reveals a substantial burden in early-onset colorectal cancer in Canada, with a significant increase in incidence over time and over 160 DALYs/100,000 population.

Figure 1: Incidence (A), Mortality (B) and DALYs (C) for EOCRC in Canada between 1990 and 2019 with 95% CIs.

Funding Agencies
None
A163 CATCHING CANCERS EARLY? AGE AND STAGE AT DIAGNOSIS OF COLORECTAL CANCER IN FIRST NATIONS PEOPLE IN ONTARIO COMARED TO OTHER ONTARIANS
Authors: Tinmouth J , Sutradhar R , Liu N , Senese L , Leylachian S , Chiarelli A , Kewayosh A , Kupets R , Tammemagi M , Sheppard A 
Published: February 2024

Abstract

Background
Historically, Indigenous peoples in Canada were at lower risk for cancer compared to non-Indigenous people. Data from prior to 2010 suggested that First Nations in Ontario had higher incidence & poorer survival from colorectal cancer (CRC). The current project arose from concerns raised by Indigenous partners about community members being diagnosed with colorectal cancer before screening age-eligibility.

Aims
To examine the age & stage at CRC diagnosis among First Nations people in Ontario (FN) compared to other Ontarians (ON).

Methods
With Indigenous partner support, approvals were obtained to link health administrative datasets at ICES & Ontario Health. Among others, these datasets included the Ontario Cancer Registry & the Indian Register System, a registry of FN with status, meaning they are on the official record of persons registered under section 6 of Canada’s Indian Act. We created cohorts of FN & ON aged 18-85 from 2000 to 2018, matched 1:5 on sex, age at & year of inception. For the primary analysis, we performed survival analysis, accounting for the competing event of death & using attained age as a time scale. The primary outcome was CRC diagnosis, the primary exposure was FN vs ON & we adjusted for regular screening test use, comorbidity, remoteness & having a regular primary care provider. Similarly, we examined stage at diagnosis, restricting the cohort to 2007+ due to limitations in the stage data.

Results
Baseline demographics for the 153,300 FN & 766,500 ON included are in the Table. Median (IQR) follow-up was 17 (8-20) & 18 (I8-20) years for FN & ON, respectively (p ampersand:003C0.001). There were 1,156 (0.8%) & 4,249 (0.6%) CRCs diagnosed in FN & ON, respectively (p ampersand:003C0.001). 11,213 (7.3%) FN & 25,732 (3.4%) ON died from other causes (p ampersand:003C0.001). After accounting for the competing event of death, FN were significantly more likely to be diagnosed with CRC at a younger age (HR 1.42, 95%CI: 1.32-1.53) (see Figure) & later stage (HR 1.53, 95%CI: 1.34-1.75) than ON.

Conclusions
FN with CRC were younger & presented at a later stage compared to ON with CRC. These findings have important implications for CRC screening recommendations for First Nations people in Ontario.
Baseline characteristics at cohorts inception
IQR, interquartile range

A. Cumulative incidence of colorectal cancer (primary event) & death (competing event), comparing First Nations (FN) and other Ontarians (ON). B. Focus on cumulative incidence of colorectal cancer (death as competing event, not shown), comparing FN and ON.

Funding Agencies
CIHR
A171 A MISSENSE MUTATION IN FCGBP, A STRUCTURAL COMPONENT OF MUC2 MUCUS, ALTERS THE GLYCOMICS PROFILE AND FUNCTION OF COLONIC MUCUS
Authors: Gorman H , Moreau F , Zandberg W , Bergstrom K , Chadee K 
Published: February 2024

Abstract

Background
MUC2 mucin produced by colonic goblet cells, form a mucus bilayer that provides a physical barrier between potential pathogens in the lumen and the underlying epithelial cells. Mucus is thus the first line of innate host defense in the gastrointestinal (GI) tract. Many GI diseases including inflammatory bowel disease and colon cancer affect the glycosylation of mucus. Goblet cells produce a variety of proteins that are associated with the mucus layer. Of these proteins, FCGBP is of significant interest due to its structural similarities to MUC2 mucin with unknown functions. In this study, we investigated if a missense mutation in FCGBP altered the glycosylation of goblet cell MUC2 and affected its barrier functions.

Aims
Aims:
1) To determine mechanistically how FCGBP impeded the structural integrity of the mucus layer
2) To quantify MUC2 glycoprotein modifications in the altered mucus layer

Methods
To investigate whether FCGBP impaired mucus barrier functions, two cell types were investigated: wildtype LS174T (WT) MUC2 mucus-producing goblet cells and LS174T cells with a missense mutation in FCGBP (FCGBP-Mut). To determine if FCGBP-Mut led to loss in barrier function in the mucus layer, the penetration of 0.2, 1, and 2 μm fluorescent beads (to mimic bacteria) through the mucus layer were quantified. To determine if the differences in penetrability were caused by differences in MUC2 glycosylation in the goblet cell lines, sensitive glycomic analyses were performed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). Both cells and purified MUC2 mucin granules were analyzed and confirmed by lectin binding assays. To enumerate differences in the glycomics profiles, RT-PCR was performed on over 30 human glycosyltransferases.

Results
FCGBP-Mut cells exhibited an altered glycomics profile with a significant increase in sialylated/fucosylated glycans as quantified by HPLC-MS and an increase in sialyl- and fructosyltransferase mRNA expression. In contrast to WT goblet cells, FCGBP-Mut cells exhibited significant loss in MUC2 mucus barrier function as quantified by fluorescent beads penetration through the mucus layer temporally. The altered glycosylation in FCGBP-Mut cells triggered increased metabolic stress and ROS production that enhanced susceptibility to Salmonella enterica binding, invasion and cell death.

Conclusions
This study demonstrates that a single missense mutation in FCGBP altered the penetrability of the mucus layer associated with an increase in sialylated/fucosylated glycans, a signature hallmark of numerous colonic diseases. These findings underscore the importance of FCGBP in providing structural integrity of the mucus layer and homeostatic maintenance of goblet cell glycosylation profiles.

Funding Agencies
CIHR
A178 GASTROINTESTINAL STRICTURES IN A PEDIATRIC PATIENT WITH SATOYOSHI SYNDROME
Authors: Pohoreski K , Pajunen K , Brundler M , Wrobel I 
Published: February 2024

Abstract

Background
Satoyoshi syndrome (SS) is a rare, progressive, multisystem disease including muscle spasms, alopecia, skeletal deformities, and diarrhea, with suspected autoimmune etiology. Treatment includes corticosteroids, immunoglobulin therapy, or immunosuppression. Reported endoscopic findings include loss of intestinal folds and nodularity in the stomach and the intestine, with histology showing gastritis cystica polyposa and lymphoplasmacytic infiltrate, as well as fibrosis noted on autopsy reports. To date, no cases of intestinal stricture have been described in SS.

Aims
To describe an original case of intestinal strictures in SS.

Methods
Case report and literature review.

Results
We present a case of a 10-year-old girl with chronic diarrhea and intermittent hematochezia, postprandial abdominal pain, intermittent non-bilious emesis, stunted growth, and weight loss, with acquired alopecia and severe muscle cramps. Examination showed a non-dysmorphic, small child with alopecia totalis and a distended, tender abdomen. Investigations demonstrated an unremarkable endocrine work-up, mild hypoalbuminemia, microcytic anemia, and anti-transglutaminase serology at 3-4x ULN with no improvement on the gluten-free diet. Endoscopy identified a duodenal stricture with a very distended stomach and duodenal bulb, mucosal nodularity and bridging creating a web-like appearance, and edema and friability of the left-sided colon. MR enterography confirmed an isolated duodenal stricture. Pathology displayed patchy fibrosis with crypt/glandular dilatation in the antrum, duodenum, and rectum. Skeletal imaging detected physeal widening and sclerosis with mild slipping of the epiphyses. Auto-immune markers included positive ENA profile for anti-Sm, anti-Sm/RNP, and anti-RNP-A. The patient was treated with corticosteroids in addition to a series of endoscopic dilatations for duodenal stricture with symptomatic benefit, with addition of upadacitinib for alopecia management. Follow-up revealed intermittent worsening of symptoms with steroid taper, necessitating further duodenal dilatations, and evidence of a new anal stricture. The patient remains on corticosteroid therapy with ongoing surveillance.

Conclusions
This case identifies the first report of intestinal strictures in SS, which may suggest that in addition to suspected autoimmune pathogenesis, disorders of fibrogenesis may need to be considered.

Funding Agencies
None
A181 EXPLORING THE ROLE OF KLEBSIELLA VARIICOLA AND KLEBSIELLA PNEUMONIAE IN PEDIATRIC ULCERATIVE COLITIS PATHOGENESIS
Authors: Arjomand Fard N , Bording-Jorgensen M , Cheng C , Kerr K , Aujla H , Mansour S , Elhenawy W , Perry T , Wine E 
Published: February 2024

Abstract

Background
Recent studies indicated that Klebsiella (K) pneumoniae (isolated from the stool of IBD patients) and K. variicola (isolated from the mesenteric tissue of Crohn disease patients) have the potential to induce inflammation in epithelial and preadipocyte cells, exacerbating colitis in murine models.

Aims
We isolated these strains from pediatric ulcerative colitis (UC) patients' appendix (relevant to UC pathogenesis given the protective effects of appendectomy) and other non-inflamed colon sections. We hypothesized that these isolates are invasive and induce inflammation in UC. These strains have not been previously studied in UC.

Methods
K. variicola and K. pneumoniae were isolated from two pediatric UC patients' appendices and other non-inflamed colon sections and identified using 16S DNA Sanger sequencing. Virulence of the two strains was determined by infecting Caco2 cell lines and performing adhesion and invasion assays, quantifying biofilm formation, and assessing barrier functions using transepithelial electrical resistance (TEER) measurement. Importantly, we monitored the production of pro-inflammatory (e.g., IL-8, TNF-α) and anti-inflammatory (IL-10) cytokines using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR).

Results
K. variicola and K. pneumoniae exhibited high levels of biofilm formation compared to adherent-invasive Escherichia coli (AIEC), which are commonly isolated from IBD patients. Furthermore, the Klebsiella strains adhered to epithelial cells within 2-3 hours post infection. TEER experiments showed compromised barrier integrity after 6 hours and overnight infection. Except for K. pneumoniae isolated from the ascending colon, the tested strains exhibited a significant increase in IL-8 expression. Similarly, K. variicola from the peri-appendicular region demonstrated elevated TNF-α gene expression.

Conclusions
K. variicola and K. pneumoniae isolated from UC patients have the potential to form biofilms, disrupt barrier integrity, and trigger inflammatory responses. These findings unravel a potential role for pathogenic Klebsiella strains in driving UC pathogenesis. Importantly, these data shed light on the role of appendix-associated bacteria in the development of UC. Future work includes using comparative genomics to map the virulence determinants of these bacteria.

Funding Agencies
CIHRWomen and Children's Health Research Institute (WCHRI)
A189 INVESTIGATING THE ROLE OF BACTERIAL HISTAMINE METABOLISM IN VISCERAL HYPERALGESIA
Authors: Ross T , Pujo J , Hall-Bruce M , Collins S , Vanner S , Reed D E , Bercik P , De Palma G 
Published: February 2024

Abstract

Background
Intestinal microbiota have been implicated in the expression of irritable bowel syndrome (IBS) as patients present with altered gut microbial profiles and microbial metabolic activity. We have previously identified bacterial histamine to strongly influence mast cell accumulation through only IBS activation of the H4 receptor, leading to visceral hyperalgesia in a subset of patients with IBS. We hypothesize that a subset of IBS patients with high histamine-producing microbiota exhibit an aberrant histamine metabolism. Investigating the microbiota-driven pathways involved in histamine metabolism is key to understanding abdominal pain pathophysiology in IBS patients.

Aims
1. To study whether variations of histamine levels are due to bacterial metabolism using in vitro and in vivo approaches.
2. To identify the prevalence of high histamine-producing and histamine-degrading bacteria in a clinical cohort via in silico analyses.

Methods
Using in vitro approaches, stool samples from healthy control (HC) donors and IBS patients were inoculated in minimal media in aerobic/anaerobic conditions, with/without excess histidine or added histamine. Bacterial histamine production and degradation were assessed in culture supernatants by ELISA. After identification through Sanger sequencing, individual colony capacity to degrade and produce histamine was assessed. Host and microbial contributions to histamine metabolism will be identified through analyses of germ-free mice colonized with IBS and HC stool samples.

Results
IBS patients (n=23) tested were found to consistently produce higher levels of histamine compared to HC (n=3). Among the tested isolated colonies from IBS patients (n=179) 61% produced histamine compared to 33% of HC (n=54), and 20% degraded histamine compared to 11% of HC. Of these colonies, 13% of only IBS isolates demonstrated the capacity to both degrade and produce histamine. Facultative anaerobes were found to possess both higher production and degradation capacity. Both pH and histamine concentration determine bacterial ability to produce or degrade histamine.

Conclusions
Based on these findings, both healthy and IBS individuals exhibit varying levels of histamine production/degradation, most prominently through facultative anaerobes. The intestinal environment and bacterial community composition are major regulators of bacterial histamine metabolism. The observed in vitro capacity to produce/degrade histamine, and its biological implications, will be confirmed with gnotobiotic humanized mice, ultimately aiding in designing microbiota-directed therapies for the management of visceral hypersensitivity.

Funding Agencies
CIHRFarncombe Innovation Fund
A195 IL-13 DRIVES CROHN’S DISEASE ASSOCIATED-INTESTINAL FIBROSIS IN SHIP DEFICIENT MICE
Authors: Safari K , Menzies S C , Sly L M 
Published: February 2024

Abstract

Background
Crohn’s disease (CD) is an immune-mediated disease characterized by chronic, relapsing and remitting, or progressive inflammation of the digestive tract. One in 3 people with CD will develop intestinal fibrosis requiring surgery within 10 years of diagnosis. Biological therapy is effective at reducing inflammation in CD and early and aggressive treatment with biologics will reduce the incidence of fibrosis. However, in children, for whom a step-up approach to therapy is used, and populations that are refractory to biological therapy; fibrosis remains a serious concern. Treatments are urgently needed as currently there are no treatments that target intestinal fibrosis directly in CD.
Mice deficient in the Src homology 2 domain-containing inositolpolyphosphate 5’-phosphatase (SHIP-/-) develop spontaneous CD-like ileal inflammation and fibrosis. Fibrosis is dependent on PI3Kp110δ activity. IL-4 and IL-13 lead to downstream activation of PI3Kp110δ. Recent work in our lab has shown through pharmacological inhibition that the development of fibrosis in SHIP-/- mice is dependenet on IL-13 signaling, but not IL-4.

Aims
Aim 1: To determine whether genetic ablation of IL-13 prevents ileal fibrosis in SHIP-/- mice
Aim 2: To determine the cellular source of IL-13 in the distal ileum of SHIP-/- mice
Aim 3: To determine the cellular source of IL-13 in the distal ileum of individuals with CD

Methods
SHIP-/- mice were crossed with IL-13 deficient mice (IL13-/-) to generate SHIP+/+IL13+/+, SHIP+/+IL13-/-, SHIP-/-IL13+/+, and SHIP-/-IL13-/- mice. Measurements of ileal fibrosis included gross and histopathology, muscle thickening, and collagen accumulation (Masson’s trichrome staining for fibrosis). Single cell RNA sequencing (snRNA-seq) was performed on the distal ileum of SHIP-/- mice to determine the cellular source of IL-13. Previously published scRNA-seq data were analyzed to determine the cellular source of IL-13 in individuals with CD.

Results
Genetic ablation of IL-13 in SHIP-/- mice (SHIP-/-IL13-/-) reduced the development of ileal fibrosis. Analysis of single cell RNA sequencing data (scRNA seq) has revealed mast cells as the cellular source of IL-13 in the distal ileum of people with CD.

Conclusions
Mast cell derived IL-13 may be driving the development of intestinal fibrosis in CD. Our data suggest that an antibody-based biologic targeting IL-13 may be an effective strategy to prevent fibrosis in people with Crohn’s Disease.

Funding Agencies
CAG, CIHR