A39 HEALTHY FIRST-DEGREE RELATIVES FROM MULTIPLEX FAMILIES VERSUS SIMPLEX HARBOR A HIGHER RISK OF DEVELOPING CROHN'S DISEASE AND ARE ASSOCIATED WITH SUBCLINICAL INFLAMMATION AND ALTERED MICROBIOME COMPOSITION

Background

Healthy individuals within families with multiple affected members (multiplex families) with Crohn’s disease (CD) have a notably high risk of developing CD. No large prospective pre-disease cohort has assessed differences in preclinical intestinal inflammation, permeability, fecal microbiome, and genetics in healthy at-risk subjects from multiplex families.

Purpose

We aimed to assess differences in subclinical gut inflammation, genetic risk, gut barrier function, and fecal microbiota composition between first-degree relatives (FDRs) from families with 2 or more affected members (multiplex) and families with only one affected member (simplex). Also, we aimed to assess the risk of future CD onset in subjects from multiplex versus simplex families.

Method

We utilized the GEM Project cohort of healthy FDRs of CD patients. Subclinical gut inflammation was assessed using fecal calprotectin (FCP) at recruitment. Gut barrier function was assessed using the lactulose-to-mannitol ratio (LMR). For assessment of the CD-related genetic risk, CD-polygenic risk scores (CD-PRS) were calculated. Microbiome composition was assessed by sequencing fecal 16S ribosomal RNA. Generalized estimating equations logistic regression and LEfSe (PMID: 21702898) were used to assess the associations between multiplex status and different outcomes. A Cox proportional hazards model was used to assess time-related risk of future onset of CD.

Result(s)

4385 subjects were included. Median age was 17 [IQR 12-24] years, 52.9% were female, 69.4% were siblings and 30.6% were offspring. 4052 (92.4%) and 333 (7.6 %) were simplex and multiplex subjects, respectively. After adjusting for age, sex, family size, and relation to proband, multiplex status was significantly associated with higher baseline FCP (p=0.038), but was not associated with either baseline LMR or CD-PRS (p=0.19 and p=0.33, respectively).

We found no significant differences in alpha diversity (Shannon index) (p=0.57) between simplex and multiplex subjects. Beta diversity analysis assessed by the Bray-Curtis dissimilarity index did not reveal significant differences (R2=3e-04, p=0.607). The genera Eisenbergiella, Eggerthellaceae uncultured, and Morganella, were significantly more abundant in multiplex subjects, whereas Lachnospira, Sutterella, Lachnospiraceae_NK4A136_group, and Lachnospiraceae_UCG_004 less abundant.

The risk of CD onset was significantly higher in multiplex subjects. In multivariable analysis, multiplex status at recruitment was associated with increased risk of CD onset (adjusted HR 3.41, 95% CI 1.70-6.87, p=0.00055), after adjusting for demographics, FCP, LMR, and CD-PRS.

Conclusion(s)

Multiplex status compared to simplex is associated with a 3.4-fold increased risk of CD onset, a higher FCP, and fecal bacterial composition. A comprehensive assessment of environmental factors that increase CD risk in multiplex families remains to be elucidated in future studies.

Disclosure of Interest

None Declared

A218 ASSOCIATIONS BETWEEN ADHERENCE TO LITERATURE-DERIVED DIETARY INDICES AND PRE-DISEASE BIOMARKERS: IMPLICATIONS FOR CROHN’S DISEASE PREVENTION

Background

The incidence of Crohn’s disease (CD) is increasing globally, indicating a significant environmental influence such as diet. A plethora of dietary adherence (DA) patterns exist in the literature: the Mediterranean Diet (MD), Empirical Dietary Inflammatory Pattern (EDIP), Specific Carbohydrate Diet (SCD), and low Fermentable Oligosaccharide, Disaccharide, Monosaccharide, or Polyol diet (FODMAP) are all potential candidates to maintain a reduced level of inflammation, improving gastrointestinal function. Contrary, the Westernized diet (WD) is generally reported as a diet promoting inflammation in humans.

Purpose

To determine if DA to literature-derived dietary indices in a cohort of first-degree relatives (FDRs) of CD patients can modulate pre-disease biomarkers.

Method

We used food frequency questionnaire (FFQ) data from 2,696 healthy FDR subjects of the Crohn’s Colitis Canada- Genes, Environment, Microbial (CCC-GEM) project. We rederived each of the following scores using our FFQ data, utilizing originally described methods for the MD, EDIP, SCD, low FODMAP, and WD to obtain DA. Each diet was correlated pairwise via Kendall’s Tau.

We fit multivariable regression models to identify the association of DA (top quintile vs remaining) and: i) intestinal permeability using urinary fractional excretion of lactulose to mannitol ratio (LMR), LMR≥0.03 defined abnormal; ii) subclinical inflammation using fecal calprotectin (FCP) measured with BÜHLMANN fCAL® ELISA, FCP≥250µg/g defined inflammation; and iii) fecal microbiome richness and composition using 16S rRNA sequencing. Two-sided p<0.05 for primary and q<0.05 for secondary analysis defined significance.

Result(s)

There were positive correlations between the MD, SCD, and low FODMAP, these diets negatively correlated with the WD. The EDIP negatively correlated with the SCD and low FODMAP, did not correlate with the MD, and positively correlated with the WD. No diet was associated with abnormal LMR or FCP. Only the SCD was associated with increased microbial richness (q=0.03). All diets were associated with microbial genera: the MD (n=18 taxa, (2.0^-7<q-values< 0.04), EDIP (n=9, [2.8^-4-0.05]), SCD (n=13, [3.7^-11-0.05]), low FODMAP (n=14, [1.3^-7-0.05]), and WD (n=1, [0.03]).

Conclusion(s)

This study shows that literature-derived dietary indices correlate generally with each other, yet none were not associated with abnormal LMR or FCP. However, we found that diet can impact microbiome richness and composition. Thus, it is tempting to speculate that diet is a possible intervention capable of maintain microbiome homeostasis to reduce future risk of CD.

Submitted on behalf of the CCC-GEM consortium.

Funding

Crohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III

The Leona M. and Harry B. Helmsley Charitable Trust

Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Disease

Disclosure of Interest

None Declared

A238 BILE ACID COMPOSITION AND DIETARY FAT: IMPLICATIONS FOR CROHN’S DISEASE IN A COHORT OF HEALTHY FIRST-DEGREE RELATIVES

Background

Crohn’s disease (CD) is a chronic relapsing inflammatory disease of the gastrointestinal tract. The etiology of CD may arise from complex interactions including host genetics, diet, and the intestinal microbiome. Increased consumption of saturated fats, characteristic of the Western diet, is a known risk factor for CD. Dietary fat (DF) is absorbed by the host through the release of primary bile acids (PBAs) and bio-transformed by the microbiome into secondary bile acids (SBAs). Altogether, bile acids (BAs) can act as signaling molecules involved in host immune regulation and potentially in CD onset.

Purpose

To investigate the relationship between CD risk, BAs, and DF, and evaluate the predictive performance of CD onset of these factors by developing machine learning models.

Method

We used samples healthy first-degree relatives (FDRs) recruited as part of the Crohn’s Colitis Canada- Genes, Environment, Microbial (GEM) project. Those who developed CD (n=87) were matched 1:4 by age, sex, follow-up time, and geographic location with control FDRs remaining healthy (n=347).

Serum, urine, and stool BA were measured using ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy. DF types were derived from food frequency questionnaire data. We used conditional logistic regressions to identify associations between CD onset, BAs (n=93), and DFs (n=9). We further explored the relationships of significant CD-related BAs and DF via Generalized Estimation Equations. Finally, we used a tree-based machine-learning algorithm (XGBoost) with 5-fold cross-validation to assess the prediction performance of CD onset using BA from all sources as well as DF. Two-sided p<0.05 was considered significant.

Result(s)

In total, 10 of 93 BAs, and two of nine DFs were significantly associated with increased odds of CD onset (p<0.05). Additionally, five BAs were significantly associated with DF (p<0.05). Serum-derived BAs had the best predictive performance for CD, with a mean AUC of 0.70 [95% CI: 0.63;0.76], followed by stool derived BAs with a mean AUC= 0.65 [0.55;0.75], and followed by urine derived Bas with a mean AUC= 0.57 [0.48;0.66]. Lastly DF was not a predictive marker of CD onset with a mean AUC= 0.50 [0.41;0.60].

Conclusion(s)

This study suggests that BAs are associated with the pathogenesis of CD and the effects may be influenced by DF. Serum-derived BAs may be able to better predict the risk of CD than other stool or urine derived BA, while DF is not directly implicated in CD risk.

Submitted on behalf of the CCC-GEM consortium.

Funding

Crohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III

The Leona M. and Harry B. Helmsley Charitable Trust

Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

The International Organization for the Study of Inflammatory Bowel Diseases (IOIBD)

Jingcheng Shao is the recipient of a Data Science Institute Summer Undergraduate Data Science award

Disclosure of Interest

None Declared

A175 DISEASE ACTIVITY IN FIRST TRIMESTER IS ASSOCIATED WITH REDUCED GROWTH IN INFANTS BORN TO WOMEN WITH INFLAMMATORY BOWEL DISEASE

Background

Ulcerative colitis (UC) and Crohn’s disease (CD) are chronic inflammatory bowel diseases (IBD) that affect a significant portion of women in childbearing years. It is known that disease activity in early pregnancy negatively impacts obstetrical and perinatal outcomes, but the impact on infant growth is largely unknown.

Aims

The objective of this study was to compare the growth of infants born to women with active IBD during pregnancy versus those born to women with IBD in remission during pregnancy.

Methods

We conducted a prospective cohort study in a Canadian tertiary centre comprised of 98 pregnant women with IBD (63 with UC and 35 with CD) and 13 healthy pregnant women. We collected maternal demographic at trimester 1 and assessed disease activity at each trimester using clinical disease scores and fecal calprotectin. We then collected perinatal outcomes at delivery and followed the infants’ growth and feeding habits up to 12 months of age.

Results

A total of 103 mother-infant pairs were included in the study, of which 88 infants were born to women with IBD, and 15 born to women with active disease at trimester 1. Active disease at trimester 1 was associated with more adverse obstetrical outcomes, reduced 1-minute and 5-minute APGAR scores and more frequent NICU admissions. Infants born to women with active trimester 1 disease had reduced weight-for-age and length-for-age Z scores up to 6 months of age, in the absence of difference in feeding patterns. In addition, women with active disease at trimester 1 had increased expression of IL-8 and IFN-γ compared to those with trimester 1 remission.

Conclusions

Active IBD during first trimester is correlated with decreased infant weight and height up to 6 months of age, suggesting that strict disease control during first trimester, or even preconception, is essential for optimizing infant growth and perinatal outcomes.

Funding Agencies

None

A238 ALTERED GUT MICROBIOME COMPOSITION AND FUNCTION ARE ASSOCIATED WITH GUT BARRIER DYSFUNCTION IN HEALTHY RELATIVES OF CROHN’S DISEASE PATIENTS

Background

The gut microbiome may play a role in gut barrier homeostasis including epithelial barrier function, but data are scarce and limited to animal studies

Aims

To assess if alterations in gut microbiome are associated with gut barrier function

Methods

We utilized the Genetic Environmental Microbial (CCC GEM) cohort of healthy first-degree relatives (FDRs) of Crohn’s disease (CD) patients. Gut barrier function was assessed using the ratio of urinary fractional excretion of lactulose to mannitol (LMR). Stool bacterial DNA was extracted and sequenced for the V4 hypervariable region of the 16S rRNA gene using MiSeq and processed using QIIME2. Microbial functions were imputed using PICRUSt2. The cohort was divided into a North American discovery cohort (n=2,472) and non-North American external validation cohort (n=655). LMR>0.025 was defined as abnormal. LMR-microbiome associations were assessed using multivariable regression model and Random Forest (RF) classifier algorithm. q<0.05 was considered significant when multiple tests were performed

Results

The median age of the entire cohort was 17.0 years [IQR 12.0; 24.0], 52.6% were females and 25.4% had LMR>0.025. In the discovery cohort, subjects with LMR>0.025 had markedly reduced alpha diversity (Chao1 index, estimate= -0.0037, p=4.0e-04) and altered beta diversity (Bray-Curtis dissimilarity index, PERMANOVA: pseudo-F statistic = 2.99, p=1.0e-03). We identified eight bacterial genera and 52 microbial pathways associated with LMR>0.025 (q<0.05). Four genera (decreased Adlercreutzia [odds ratio(OR)=0.74, 95% confidence interval (CI) 0.6–0.91], Clostridia-UCG-014 [OR=0.71, 95%CI 0.59–0.86], and Clostridium-sensu-stricto-1 [OR=0.75, 95%CI 0.61–0.92] and increased Colidextribacter [OR=1.65, 95%CI 1.2–2.26]) and eight pathways (including decreased biosynthesis of glutamate [OR=0.4, 95%CI 0.21–0.74], tryptophan [OR=0.06, 95%CI 0.01–0.27] and threonine [OR=0.038, 95%CI 0.003–0.41]) were replicated. Bacterial community composition was associated with gut barrier homeostasis as defined by the RF analysis (p= 1.4e-6)

Conclusions

Gut microbiome community and pathways are associated with gut barrier function. These findings may identify potential microbial targets to modulate barrier function

Submitted on behalf of the CCC-GEM Consortium

Funding Agencies

CCC, CIHRCrohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III; The Leona M. and Harry B. Helmsley Charitable Trust; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

A157 DEFINITIONS OF MEDITERRANEAN DIET INCONSISTENTLY ASSOCIATE WITH MARKERS OF GUT BARRIER FUNCTION OR SUBCLINICAL INFLAMMATION IN A POPULATION-BASED COHORT

Background

The Mediterranean Diet (MD) is proposed to reduce the risk of Crohn’s disease (CD) onset in cohort studies, with inconsistent results. This inconsistency may be due to heterogeneity in defining MD scores. Additionally, relationships between MD compliance and intestinal permeability or sub-clinical inflammation are not defined.

Aims

We examined correlations between different MD scores, and determined associations between MD compliance and intestinal permeability or subclinical inflammation in a cohort of first degree relatives of CD patients.

Methods

We used food frequency questionnaire data from 2,112 subjects of the Crohn’s Colitis Canada- Genes, Environment, Microbial (CCC-GEM) project. We obtained 12 MD definitions from the literature and calculated daily percent compliance, we further compared MD scores via pairwise correlations (Kendall’s Tau). We measured intestinal permeability via urinary fractional excretion ratio of lactulose to mannitol (LMR) (LMR≥0.03 defined abnormal), and subclinical inflammation via fecal calprotectin (FCP) measured with BÜHLMANN fCAL® ELISA (FCP≥250 defined abnormal). We fit multivariable regression models between MD compliance and abnormal LMR and FCP, respectively. Two-sided p&lt;0.05 defined significance.

Results

There was large variation in cross-correlations among MD scores, from nil (t=0.0, p=0.54) to highly significant (t=0.97, p&lt;2.2e-16). Associations of MD compliance and abnormal LMR or FCP were in both directions of effect, largely non-significant. Of the 12 MD scores, none associated with abnormal LMR, while 4 associated with abnormal FCP-Odds Ratios =1.22, 1.23, 1.24, and 1.30; p=0.02, 0.02, 0.01, and 0.009, and 95% Confidence Intervals = [1.03,1.45], [1.04,1.45], [1.05,1.47], and [1.07,1.59] respectively. No diet remained significant after correcting for multiple testing.

Conclusions

Currently MD definitions vary widely. Despite discrepancies, we expected consistent directions of effect for MD compliance on LMR or FCP. The largely non-significant associations between MDs suggest limitations in definition, interpretation, and relation to biological outcomes.

Submitted on behalf of the CCC-GEM consortium.

Funding Agencies

CIHRCrohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III;The Leona M. and Harry B. Helmsley Charitable Trust; Justine Timpano is a recipient of a fellowship award from Mount Sinai Hospital; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

Metastatic atypical renal tumour with metanephric characteristics treated with Sunitinib

Metanephric Adenoma (MA) is a rare and unclassifiable renal tumour with sparse reported clinical and morphological features. Generally MA's have a benign course without recurrence after nephrectomy, however a few cases received oncological treatment due to malignant progression.

We present a 42-year-old woman who years after an initial nephrectomy developed several processes and biopsy confirmed recurrence of MA. Sunitinib was given for only two weeks, as she developed side-effects and currently the patient undergoes control scans with only minimal growth of the processes.

This is the first case of MA treated with Tyrosin-Kinase-Inhibitor.

A32 EMPAGLIFOZIN IMPROVES GASTROINTESTINAL INFLAMMATION IN A MOUSE MODEL OF COLITIS

Background

Empagliflozin (EMPA) is a highly selective sodium glucose cotransporter-2 (SGLT2) inhibitor and is increasingly being utilized as an antihyperglycemic agent in the management of type 2 diabetes. Interestingly, it has been demonstrated in human trials that EMPA treatment exerts potent cardioprotective effects by reducing cardiac inflammation independently of glycemic control. Further, EMPA has also been shown to suppress LPS-induced renal and systemic inflammation in an animal model. Based on these findings, we hypothesized that EMPA treatment may also be effective in reducing gut inflammation.

Aims

The aim of this study was to examine the effects of treatment with EMPA on gastrointestinal inflammation in an animal model of inflammatory bowel disease and to determine mechanistic insights regarding its direct effects on gut cytokine secretion.

Methods

Adult male and female IL-10-/- mice with established colitis were treated with a daily gavage of EMPA (10mg/kg; n=10) or vehicle (n=10) for 14 days. Disease activity was assessed by measurement of mouse weight, colonic weight and length, histological score, cytokine levels in colonic homogenate and lipocalin-2 levels in stool. To examine for possible direct effects of EMPA, colonic explants from wild-type (n=8) and IL-10-/- (n=8) mice were incubated with increasing doses of EMPA (0.1–5 µM) ± LPS (10µg/ml) for 2 hours and tissue levels of IL-1β and TNFα protein measured by ELISA.

Results

After 14 days EMPA treated IL-10-/- mice had a significant improvement in colonic inflammation as evidenced by decreased colonic weight to length ratio (p=0.019), decreased fecal lipocalin-2 (p=0.03), as well as decreased enterocyte injury (p=0.01), decreased lamina propria neutrophils (p=0.01) and decreased total histological score (p=0.006). EMPA treated mice also maintained their weight over the 14 days while untreated mice continued to lose weight (p=0.04). There were no significant differences in colonic homogenate levels of TNFα, IL-1β, or IL-6 or in blood glucose levels between EMPA-treated mice and controls. In addition, EMPA did not suppress levels of basal or LPS-induced TNFα and IL-1β in colonic explants from either wild-type or IL-10-/- mice suggesting that the beneficial effects in IL-10-/- mice were not due to direct effects of EMPA on colonic TNFα or IL-1β cytokine levels.

Conclusions

EMPA treatment dramatically improved histologic and fecal inflammatory markers and maintained body weight in adult IL-10-/- mice with established colitis. These findings suggest further investigations into the effects of EMPA in treating gut inflammation are warranted.

Funding Agencies

CAG, CIHR

A16 FIBER SUPPLEMENTATION DIFFERENTIALLY MODULATES RESPONSES TO FECAL MICROBIAL TRANSPLANTATION IN PATIENTS WITH METABOLIC SYNDROME AND SEVERE OBESITY: A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED PILOT TRIAL

Background

Fecal microbial transplantation (FMT) from lean donors to obese patients with metabolic syndrome (MS) has been associated with promising yet short-term metabolic improvements. The concept of using dietary or fiber supplementation to enhance effects induced by FMT has been much discussed in the literature, but to date no human trials have examined this concept.

Aims

The aim of this study was to determine if fiber supplementation following FMT was able to enhance or sustain FMT-mediated metabolic benefits.

Methods

We performed a 12-wk double-blind randomized placebo-controlled trial in patients with severe obesity and MS recruited from Edmonton’s Bariatric Clinic from 2018 to 2019. Patients were stratified by sex and block randomized 1:1:1:1 amongst one of four groups: (1) Placebo FMT and a non-fermentable fiber (NF) (2) Placebo FMT and fermentable fiber (FF); (3) FMT and non-fermentable fiber (FMT-NF); and (4) FMT and fermentable fiber (FMT-FF). Patients received a single dose of FMT (50g donor stool) with 20 oral capsules followed by a 6-wk period of daily fiber. The primary outcome was evaluating mean differences (MD) in insulin sensitivity from baseline to 6-wks using the homeostatic model assessment of insulin resistance (HOMA2-IR).

Results

Sixty-eight patients were randomized with 61 completing the primary outcome (NF = 17; FF = 15; FMT-NF = 14; FMT-FF = 15) and evaluated using a modified intent-to-treat analysis. Baseline characteristics were similar with a mean BMI 45 ± 7 kg/m2, a female predominance (83.6%), and a HOMA2-IR of 3.43 ± 2.2. There were no baseline differences in clinical characteristics, metabolic parameters, medications, or dietary intake. FMT-NF had improvements in HOMA2-IR (MD -24.0% ± 12.0%; p=0.02), insulin sensitivity (MD 27.6% ± 12.3%; p=0.02), and insulinemia (MD -25.4% ± 12.3%; p=0.02) from baseline to 6-wks (Figure 1). These benefits were associated with increased microbial richness and improvements in GLP-1 metabolism. Linear mixed model regression revealed that select bacterial taxa including Phascolarctobacterium, Ruminococcaeceae, and B. stercoris correlated with increased insulin sensitivity. Findings occurred in the absence of changes in anthropometric parameters, dietary intake, medication regimen and were not observed in groups receiving fermentable fiber or in any group following cessation of fiber.

Conclusions

This proof-of-concept trial provides evidence that a single FMT dose combined with daily non-fermentable fiber supplementation can successfully improve insulin resistance in patients with metabolic syndrome and severe obesity on optimized medical therapy.

Funding Agencies

W. Garfield Weston Foundation

A169 EXPLORING PATIENT PERSPECTIVES ON AN ONLINE STRESS REDUCTION BASED WELLNESS INTERVENTION IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE (IBD)

Background

Despite strong connections between stress and inflammatory bowel disease (IBD) associated symptoms, there has been limited research on stress reduction interventions for patients with IBD. Moreover, the research that has been conducted on this topic has shown mixed results with very few studies having used qualitative methodology to explore the patient experience.

Aims

Our objectives for this study were to explore: (i) the experience of having IBD, (ii) the influence of an online 12-week stress reduction program on participant’s physical and emotional symptoms of IBD and (iii) the acceptability of the online program.

Methods

We used a qualitative descriptive approach embedded within a larger randomised control trial (RCT) to explore the experiences of participants. Upon completion of the program, participants were invited to participate in semi-structured interviews. Interviews were analysed through an inductive process whereby transcripts were coded, with codes grouped into larger categories and then themes. Data collection and analysis occurred in a concurrent and iterative manner to enable refinement of interview questions and reflections on the research process.

Results

We analysed a total of 55 interviews. Three main themes emerged from the data: (i) IBD as a source of stress and uncertainty, (ii) understanding the positive impacts of the stress reduction program, and (iii) enhancing program desirability. Participants reported a reduction in IBD symptom burden with improvements in their ability to manage everyday and disease-associated stressors, while building a positive mindset. Weekly check-ins with program facilitators enabled participants to build routine, enhancing accountability. Variation in program content and fostering connections with others in the IBD community were identified as potential program improvements.

Conclusions

Our findings highlight the debilitating nature of IBD, with participants reporting significant disruptions to daily activities, uncertainty, and stress which served to worsen symptoms. Stress reduction programs like the one explored in our study offer an accessible avenue for reducing perceived stress, enhancing resilience and improving the physical condition of individuals diagnosed with IBD. Future research should explore the application of online stress reduction programs in patients experiencing other gastrointestinal disease.

Funding Agencies

CIHRUniversity Hospital Foundation, American College of Gastroenterology, CIHR IMAGINE grant

A31 COMPLEX ROLE OF DIETARY FIBERS IN IBD: MICROBES MEDIATE FIBER-INDUCED INFLAMMATION

Background

Dietary fibers pass through the bowel undigested and are fermented within the intestine by microbes, typically promoting gut health. However, many IBD patients describe experiencing sensitivity to fibers. β-glucan, found on the surface of fungal cells during fungal infection, has been shown to bind to fiber receptors, such as Dectin-1, on host immune cells, resulting in a pro-inflammatory response. These fungal fibres share properties with dietary fibers.

Aims

As an altered gut microbial composition has been associated with IBD, we hypothesized that the loss of fiber-fermenting microbes populating the gut in IBD could lead to dietary fibers not being efficiently broken down into their beneficial biproducts (e.g. short chain fatty acids; SCFA), resulting in binding of intact fibers to pro-inflammatory host cell receptors.

Methods

Immune and epithelial cell lines and colonic biopsies cultured ex vivo were incubated with oligofructose or inulin (5g/L), or pre-fermented fibers (24hr anaerobic fermentation). Immune responses were measured by cytokine secretion (ELISA), and expression (qPCR). Barrier integrity was measured by transepithelial resistance (TEER). Food frequency questionnaire (FFQ) data of patient fiber consumption were correlated with gut microbes (shotgun sequencing) and immune responses to fiber in patient biopsies.

Results

Unfermented oligofructose induced IL-1β secretion in leukocytes (macrophage, T cell, neutrophil) and in colon biopsies from pediatric Crohn disease (CD; n=38) and ulcerative colitis (UC; n=20) patients cultured ex vivo, but not in non-IBD patients (n=21). IL-1β secretion was greater in patients with more severe disease. Pre-fermentation of oligofructose by whole-microbe intestinal washes from non-IBD patients or remission patients reduced secretion of IL-1β, while whole microbe intestinal washes from severe IBD patients were unable to ferment oligofructose or reduce cytokine secretion. Fiber effects on IL-1β secretion in biopsies positively correlated with effects on barrier integrity in T84 cells. Fiber-associated immune responses in patient biopsies cultured ex vivo (ELISA) correlated with fiber avoidance (FFQ) and gut microbiome (sequencing) in matching patient samples.

Conclusions

Our findings demonstrate that intolerance and avoidance of prebiotic fibers in select IBD patients is associated with the inability to ferment these fibers, leading to pro-inflammatory immune responses and intestinal barrier disruption. This highlights select disease state scenarios, in which administration of fermentable fibers should be avoided and tailored dietary interventions should be considered in IBD patients.

Funding Agencies

CIHRWeston Foundation

Illuminating gravitational waves: A concordant picture of photons from a neutron star merger

Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma rays seen in EM170817 are dissimilar to classical short gamma-ray bursts with ultrarelativistic jets. Instead, we suggest that breakout of a wide-angle, mildly relativistic cocoon engulfing the jet explains the low-luminosity gamma rays, the high-luminosity ultraviolet-optical-infrared, and the delayed radio and x-ray emission. We posit that all neutron star mergers may lead to a wide-angle cocoon breakout, sometimes accompanied by a successful jet and sometimes by a choked jet.

Unaffected twins discordant for affective disorders show changes in anterior callosal white matter microstructure

OBJECTIVE

The neurobiological mechanisms mediating an increased risk to develop affective disorders remain poorly understood. In a group of individuals with a family history of major depressive (MDD) or bipolar disorder (BD), we investigated the microstructural properties of white matter fiber tracts, that is, cingulum bundle, uncinate fasciculus, anterior limb of the internal capsule, and corpus callosum, that facilitate the communication between brain regions implicated in affective disorders.

METHOD

Eighty-nine healthy mono- or dizygotic twins with a co-twin diagnosed with MDD or BD (high-risk) and 57 healthy twins with a co-twin with no familial history of affective disorders (low-risk) were included in a diffusion tensor imaging study.

RESULT

The high-risk group showed decreased fractional anisotropy (FA), a measure of water diffusion directionality, and increased radial diffusivity in the anterior region of corpus callosum compared to the low-risk group. This abnormality was not associated with zygosity or type of depressive disorder of co-twin.

CONCLUSION

The observed decreased anterior callosal fiber FA in the high-risk group may be indicative of a compromised interhemispheric communication between left and right frontal regions critically involved in mood regulation. Reduced anterior callosal FA may act as a vulnerability marker for affective disorders in individuals at familial risk.

Physiological capacity and physical testing in male elite team handball

AIM

The aim of the present study was to examine the physical demands placed on male elite team handball players in relation to playing position.

METHODS

Male elite team handball field players were evaluated during match-play over a six season time span using physiological measurements and by subsequent physical testing.

RESULTS

Mean heart rate and relative workload during match-play (N.=41) were 163 ± 5 beats·min⁻¹ (group means±SD) and 70.9 ± 6.0% of VO(2-max), respectively. Relative workload was lower (P<0.01) in the second half vs. the first (66.3 ± 5.9% vs. 75.4 ± 5.6% of VO(2-max)). Post-match blood lactate concentration was 4.8 ± 1.9 mM (range: 2.8-10.8 mM). Mean fluid loss was 0.81 ± 0.41 l pr. match. Mean VO(2max) was 5.18 ± 0.66 l O2·min-1 corresponding to 57.0 ± 4.1 mL O₂·min⁻¹·kg⁻¹. Mean total running distance in the Yo-Yo intermittent recovery test (level 2) was 895 ± 184 m (range: 520-1360 m), which was greater in wing players (975 ± 123 m) than backcourt players (897 ± 108 m) and pivots (827 ± 264 m) (P<0.05). Fastest 30-m sprint time was 4.09 ± 0.12 s (range: 3.87-4.28 s). The repeated sprint test (7 x 30 m) yielded a mean fatigue index of -8.1 ± 2.7 %. Maximal jumping height in "Jump and Reach" testing was 0.71 ± 0.08 m (range: 0.61-0.86 m). Maximal ball throwing speed was observed using the set shot with 3-step run-up (92.8 ± 5.3 km·h⁻¹, range: 75.8-108.2 km·h⁻¹).

CONCLUSION

Modern male elite team handball imposes moderate-to-high demands on the aerobic energy system and high demands on the anaerobic energy systems during certain periods of the match. Indications of temporary fatigue and a subsequent decline in performance were observed, since the relative workload decreased both in the first and in the second half of the match. Physiological profiles and physical test results differed between playing positions, with wing players covering a greater total distance in the Yo-Yo test and showing superior jumping performance and repeated sprint running capacity than backcourt players and pivots.

The activity of satellite cells and myonuclei following 8 weeks of strength training in young men with suppressed testosterone levels

AIM

To investigate how suppression of endogenous testosterone during an 8-week strength training period influences the activity of satellite cells and myonuclei.

METHODS

Twenty-two moderately trained young men participated in this randomized, placebo-controlled, and double-blinded intervention study. The participants were randomized to treatment with a GnRH analogue, goserelin (n = 12), which suppresses testosterone or placebo (n = 10) for 12 weeks. The strength training period of 8 weeks started after 4 weeks of treatment and included exercises for all major muscles. Biopsies were obtained from the mid-portion of the vastus lateralis muscle.

RESULTS

Testosterone resting level in goserelin was 10-20 times lower compared with placebo, and the training-induced increase in the level of testosterone was abolished in goserelin. Training increased satellite cells number in type II fibres by 20% in placebo and by 52% in goserelin (P < 0.01), whereas the myonuclear number significantly increased by 12% in type II fibres in placebo and remained unchanged in goserelin (P < 0.05). No changes in satellite cells and myonuclei were seen in type I fibres in either group. Data from the microarray analysis indicated that low testosterone affects the bone morphogenetic proteins signalling, which might regulate proliferation vs. differentiation of satellite cells.

CONCLUSION

Eight weeks of strength training enhances the myonuclear number in type II fibres, and this is largely blocked by the suppression of testosterone. The data indicate that low testosterone levels could reduce the differentiation of satellite cells to myonuclei via the bone morphogenetic proteins signalling pathway, resulting in reduced increases in lean leg mass.

Match performance and physiological capacity of female elite team handball players

The present study evaluated the physical demands imposed on female elite team handball players in relation to playing position. Female elite team handball field players were examined during match-play over a 5-year period using video based computerized locomotion analysis of tournament matches. In addition, physiological measurements during match-play and in separate physical tests were carried out. A total distance of 4002±551 m (group means±SD) was covered per match with a total effective playing time of 50:42±5:50 min:s, while full-time players covered 4693±333 m. On average, each player (n=83) performed 663.8±99.7 activity changes per match, and the mean speed was 5.31±0.33 km · h(-1). High-intensity running constituted 0.8±0.5% of total effective playing time per match corresponding to 2.5±1.8% of the total distance covered. The amount of high-intensity running was reduced (p<0.05) 21.9% in the second half (44.9±16.8 m) compared to the first (57.5±21.3 m). Maximal oxygen uptake (VO2-max) was 3.49±0.37 l O2 · min(-1) corresponding to 49.6±4.8 ml O2 · min(-1) · kg(-1). Mean relative workload during match-play was 79.4±6.4% of VO2-max. Mean total running distance in the Yo-Yo intermittent recovery test (level 1) was 1436±222 m, which was greater in wing players (1516±172 m, p<0.05) than pivots (1360±118 m) and backcourt players (1352±148 m). In conclusion, modern female elite team handball is a physically demanding intermittent team sport, where players are exposed to high relative workloads with substantial estimated aerobic energy expenditure interspersed by short periods of dominant anaerobic energy production as reflected by the limited amount of high-intensity running. Indications of fatigue and a resulting decline in physical performance were identified, since the amount of high-intensity running and the relative workload levels decreased in the second half. Positional differences were observed, with wing players covering a greater total distance than backcourt players, performing more high-intensity running and demonstrating a better intermittent recovery capacity (Yo-Yo test outcome) compared to both backcourt players and pivots.

Postnatal development of the renal medulla; role of the renin-angiotensin system

Adverse events during foetal development can predispose the individual for cardiovascular disease later in life, a correlation known as foetal programming of adult hypertension. The 'programming' events have been associated with the kidneys due to the significant role in extracellular volume control and long-term blood pressure regulation. Previously, nephron endowment and functional consequences of a low nephron number have been extensively investigated without achieving a full explanation of the underlying pathophysiological mechanisms. In this review, we will focus on mechanisms of postnatal development in the renal medulla with regard to the programming effects. The renin-angiotensin system is critically involved in mammalian kidney development and impaired signalling gives rise to developmental renal lesions that have been associated with hypertension later in life. A consistent finding in both experimental animal models and in human case reports is atrophy of the renal medulla with developmental lesions to both medullary nephron segments and vascular development with concomitant functional disturbances reaching into adulthood. A review of current knowledge of the role of the renin-angiotensin system for renal medullary development will be given.

Locomotion characteristics and match-induced impairments in physical performance in male elite team handball players

The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full-time players covered 3 945±538 m. The mean speed was 6.40±1.01 km · h - 1. High-intensity running constituted only 1.7±0.9% of TPT per match corresponding to 7.9±4.9% of the total distance covered. An average of 1 482.4±312.6 activity changes per player (n=82) with 53.2±14.1 high-intensity runs were observed per match. Total distance covered was greater in BP (3 765±532 m) and WP (3 641±501 m) than PV (3 295±495 m) (p<0.05), and WP performed more high-intensity running (10.9±5.7% of total distance covered) than PV (8.5±4.3%, p<0.05) and BP (6.2±3.2%, p<0.01). The amount of high-intensity running was lower (p<0.05) in the second (130.4±38.4 m) than in the first half (155.3±47.6 m) corresponding to a decrease of 16.2%.In conclusion, modern male elite TH is a complex team sport that comprises several types of movement categories, which during match-play place moderate-to-high demands on intermittent endurance running capacity and where the amount of high-intensity running may be high during brief periods of the match. Signs of fatigue-related changes were observed in terms of temporary impaired physical performance, since the amount of high-intensity running was reduced in the second half. Notably, physical demands differed between playing positions, with WP demonstrating a more intensive activity pattern than BP and PV, respectively.