Physical activity as a modulator of intestinal health and its implications in inflammatory bowel diseases

The interactions between humans, the environment, and intestinal microbiota form a tripartite relationship that is fundamental to the overall health of the host. Disruptions in this delicate balance between the microbiota and host immunity are implicated in various chronic diseases including inflammatory bowel disease (IBD). IBD encompassing ulcerative colitis and Crohn’s disease are idiopathic, relapsing chronic inflammatory disorders of the intestinal tract with annual health care burdens of over $1.8 billion in Canada. There is no known cure for IBD, as so, novel therapeutic in its prevention and management are of great interest. Recently, physical activity (PA) has been proposed as a potential therapy in combating IBD. Here we show that higher aerobic fitness in humans is associated with increased bacterial diversity in the gut and higher abundances of butyrate, a type of short-chain fatty acid produced by resident bacteria with known anti-inflammatory properties. We confirm these findings in animal models showing that voluntary wheel running (VWR) in mice increases butyrate production. Additionally, VWR mice show increased microbial diversity, decreased expression of pro-inflammatory (TNF-α, TGF-β, and IFN-γ) and increased expression of anti-inflammatory (IL-10) cytokines suggestive of the potential to be primed against the damaging effects of chronic inflammation. These enhancements however were absent in a life-long model of mucin2 deficient (MUC2-/-) murine colitis and VWR offered no protection in these mice against disease symptoms. Taken together, these suggest that the benefits of PA against IBD are preventative in nature and cannot reverse existing disease states like those found in IBD. We further showed that certain PA-derived changes in the intestines such as microbial community changes, upregulation of IL-10, and attenuation of IFN-γ are dependent on the amount of PA while reduction of anti-inflammatory cytokines TNF-α and TGF-β can occur even under low running conditions. In summary, we showed that PA can beneficially modulate the intestinal environment in healthy hosts, leading to a primed anti-inflammatory state likely effective in IBD management during remission.Arts and Sciences, Irving K. Barber School of (Okanagan)Biology, Department of (Okanagan)Graduat

Cover Crop Diversity as a Tool to Mitigate Vine Decline and Reduce Pathogens in Vineyard Soils

Wine grape production is an important economic asset in many nations; however, a significant proportion of vines succumb to grapevine trunk pathogens, reducing yields and causing economic losses. Cover crops, plants that are grown in addition to main crops in order to maintain and enhance soil composition, may also serve as a line of defense against these fungal pathogens by producing volatile root exudates and/or harboring suppressive microbes. We tested whether cover crop diversity reduced disease symptoms and pathogen abundance. In two greenhouse experiments, we inoculated soil with a 10⁶ conidia suspension of Ilyonectria liriodendri, a pathogenic fungus, then conditioned soil with cover crops for several months to investigate changes in pathogen abundance and fungal communities. After removal of cover crops, Chardonnay cuttings were grown in the same soil to assess disease symptoms. When grown alone, white mustard was the only cover crop associated with reductions in necrotic root damage and abundance of Ilyonectria. The suppressive effects of white mustard largely disappeared when paired with other cover crops. In this study, plant identity was more important than diversity when controlling for fungal pathogens in vineyards. This research aligns with other literature describing the suppressive potential of white mustard in vineyards.Arts and Sciences, Irving K. Barber School of (Okanagan)Non UBCBiology, Department of (Okanagan)ReviewedFacult

Fish oil attenuates omega-6 polyunsaturated fatty acid-induced dysbiosis and infectious colitis but impairs LPS dephosphorylation activity causing sepsis.

Clinically, excessive ω-6 polyunsaturated fatty acid (PUFA) and inadequate ω-3 PUFA have been associated with enhanced risks for developing ulcerative colitis. In rodent models, ω-3 PUFAs have been shown to either attenuate or exacerbate colitis in different studies. We hypothesized that a high ω-6: ω-3 PUFA ratio would increase colitis susceptibility through the microbe-immunity nexus. To address this, we fed post-weaned mice diets rich in ω-6 PUFA (corn oil) and diets supplemented with ω-3 PUFA (corn oil+fish oil) for 5 weeks. We evaluated the intestinal microbiota, induced colitis with Citrobacter rodentium and followed disease progression. We found that ω-6 PUFA enriched the microbiota with Enterobacteriaceae, Segmented Filamentous Bacteria and Clostridia spp., all known to induce inflammation. During infection-induced colitis, ω-6 PUFA fed mice had exacerbated intestinal damage, immune cell infiltration, prostaglandin E2 expression and C. rodentium translocation across the intestinal mucosae. Addition of ω-3 PUFA on a high ω-6 PUFA diet, reversed inflammatory-inducing microbial blooms and enriched beneficial microbes like Lactobacillus and Bifidobacteria, reduced immune cell infiltration and impaired cytokine/chemokine induction during infection. While, ω-3 PUFA supplementation protected against severe colitis, these mice suffered greater mortality associated with sepsis-related serum factors such as LPS binding protein, IL-15 and TNF-α. These mice also demonstrated decreased expression of intestinal alkaline phosphatase and an inability to dephosphorylate LPS. Thus, the colonic microbiota is altered differentially through varying PUFA composition, conferring altered susceptibility to colitis. Overall, ω-6 PUFA enriches pro-inflammatory microbes and augments colitis; but prevents infection-induced systemic inflammation. In contrast, ω-3 PUFA supplementation reverses the effects of the ω-6 PUFA diet but impairs infection-induced responses resulting in sepsis. We conclude that as an anti-inflammatory agent, ω-3 PUFA supplementation during infection may prove detrimental when host inflammatory responses are critical for survival

High-intensity endurance training results in faster vessel-specific rate of vasorelaxation in type 1 diabetic rats.

This study examined the effects of 6 weeks of moderate- (MD) and high-intensity endurance training (HD) and resistance training (RD) on the vasorelaxation responsiveness of the aorta, iliac, and femoral vessels in type 1 diabetic (D) rats. Vasorelaxation to acetylcholine was modeled as a mono-exponential function. A potential mediator of vasorelaxation, endothelial nitric oxide synthase (e-NOS) was determined by Western blots. Vessel lumen-to-wall ratios were calculated from H&E stains. The vasorelaxation time-constant (τ) (s) was smaller in control (C) (7.2 ± 3.7) compared to D (9.1 ± 4.4) and it was smaller in HD (5.4 ± 1.5) compared to C, D, RD (8.3 ± 3.7) and MD (8.7 ± 3.8) (p<0.05). The rate of vasorelaxation (% · s(-1)) was larger in HD (2.7 ± 1.2) compared to C (2.0 ± 1.2), D (2.0 ± 1.5), RD (2.0 ± 1.0), and MD (2.0 ± 1.2) (p<0.05). τ vasorelaxation was smaller in the femoral (6.9 ± 3.7) and iliac (6.9 ± 4.7) than the aorta (9.0 ± 5.0) (p<0.05). The rate of vasorelaxation was progressively larger from the femoral (3.1 ± 1.4) to the iliac (2.0 ± 0.9) and to the aorta (1.3 ± 0.5) (p<0.05). e-NOS content (% of positive control) was greater in HD (104 ± 90) compared to C (71 ± 64), D (85 ± 65), RD (69 ± 43), and MD (76 ± 44) (p<0.05). e-NOS normalized to lumen-to-wall ratio (% · mm(-1)) was larger in the femoral (11.7 ± 11.1) compared to the aorta (3.2 ± 1.9) (p<0.05). Although vasorelaxation responses were vessel-specific, high-intensity endurance training was the most effective exercise modality in restoring the diabetes-related loss of vascular responsiveness. Changes in the vasoresponsiveness seem to be endothelium-dependent as evidenced by the greater e-NOS content in HD and the greater normalized e-NOS content in the smaller vessels

Association of Subjective and Objective Measures of Sleep With Gut Microbiota Composition and Diversity in Older Men: The Osteoporotic Fractures in Men Study.

BACKGROUND: Growing evidence suggests bidirectional links between gut microbiota and sleep quality as shared contributors to health. Little is known about the relationship between microbiota and sleep among older persons. METHODS: We used 16S rRNA sequencing to characterize stool microbiota among men (n&nbsp;=&nbsp;606, mean [standard deviation] age&nbsp;=&nbsp;83.9 [3.8]) enrolled in the Osteoporotic Fractures in Men (MrOS) study from 2014 to 2016. Sleep was assessed concurrently by a questionnaire (Pittsburgh Sleep Quality index [PSQI]), and activity monitor to examine timing (acrophase) and regularity of patterns (F-statistic). Alpha diversity was measured using Faiths phylogenetic diversity (PD). Beta diversity was calculated with robust Aitchison distance with matrix completion (RPCA) and phylogenetic-RPCA (PRPCA). Their association with sleep variables was tested with partial distance-based redundancy analysis (dbRDA). Predictive-ratio biomarkers associated with sleep measurements were identified with CoDaCoRe. RESULTS: In unadjusted analyses, men with poor sleep (PSQI &gt;5) tended to have lower alpha diversity compared to men with normal sleep (Faiths PD, beta&nbsp;=&nbsp;-0.15; 95% confidence interval [CI]: -0.30 to 0.01, p&nbsp;=&nbsp;.06). Sleep regularity was significantly associated with RPCA and PRPCA, even after adjusting for site, batch, age, ethnicity, body mass index, diabetes, antidepressant and sleep medication use, and health behaviors (RPCA/PRPCA dbRDA; p&nbsp;=&nbsp;.033/.002). In taxonomic analysis, ratios of 7:6 bacteria for better regularity (p&nbsp;=&nbsp;.0004) and 4:7 for worse self-reported sleep (p&nbsp;=&nbsp;.005) were differentially abundant: some butyrate-producing bacteria were associated with better sleep characteristics. CONCLUSIONS: Subjective and objective indicators of sleep quality suggest that older men with better sleep patterns are more likely to harbor butyrate-producing bacteria associated with better health

Individuals with substance use disorders have a distinct oral microbiome pattern

Background: Substance use disorder emerges from a complex interaction between genetic predisposition, life experiences, exposure, and subsequent adaptation of biological systems to the repeated use of drugs. Recently, investigators have proposed that the human microbiota may play a role in brain health and disease. In particular, the human oral microbiome is a distinct and diverse ecological niche with its composition influenced by external factors such as lifestyle, diet, and oral hygiene. This investigation examined whether individuals with substance use disorder (SU) show a different oral microbiome pattern and whether this pattern is sufficient to delineate the SU group from healthy comparison (HC) subjects. Methods: Participants were a sub-sample (N ​= ​177) of the Tulsa 1000 (T-1000) project. We analyzed 123 SU and 54 HC subjects using 16S rRNA marker gene sequencing to characterize the oral microbiome. Results: The groups differed significantly based on the UniFrac distance, a phylogenetic-based measure of beta diversity, but did not differ in alpha diversity. Using a machine learning approach, microbiome features combined with socio-demographic variables successfully categorized group membership with 87%–92% accuracy, even after controlling for external factors such as smoking or alcohol consumption. SU individuals with relatively lower diversity also reported higher levels of negative reinforcement experiences associated with their primary substance of abuse. Conclusions: Oral microbiome features are useful to sufficiently differentiate SU from HC subjects. There is some evidence that subjects whose drug use is driven by negative reinforcement show an impoverished oral microbiome. Taken together, the oral microbiome may help to understand the dysfunctional biological processes that promote substance use or may be pragmatically useful as a risk or severity biological marker

Cardiorespiratory fitness as a predictor of intestinal microbial diversity and distinct metagenomic functions

Background: Reduced microbial diversity in human intestines has been implicated in various conditions such as diabetes, colorectal cancer, and inflammatory bowel disease. The role of physical fitness in the context of human intestinal microbiota is currently not known. We used high-throughput sequencing to analyze fecal microbiota of 39 healthy participants with similar age, BMI, and diets but with varying cardiorespiratory fitness levels. Fecal short-chain fatty acids were analyzed using gas chromatography. Results We showed that peak oxygen uptake (VO2peak), the gold standard measure of cardiorespiratory fitness, can account for more than 20 % of the variation in taxonomic richness, after accounting for all other factors, including diet. While VO2peak did not explain variation in beta diversity, it did play a significant role in explaining variation in the microbiomes’ predicted metagenomic functions, aligning positively with genes related to bacterial chemotaxis, motility, and fatty acid biosynthesis. These predicted functions were supported by measured increases in production of fecal butyrate, a short-chain fatty acid associated with improved gut health, amongst physically fit participants. We also identified increased abundances of key butyrate-producing taxa (Clostridiales, Roseburia, Lachnospiraceae, and Erysipelotrichaceae) amongst these individuals, which likely contributed to the observed increases in butyrate levels. Conclusions Results from this study show that cardiorespiratory fitness is correlated with increased microbial diversity in healthy humans and that the associated changes are anchored around a set of functional cores rather than specific taxa. The microbial profiles of fit individuals favor the production of butyrate. As increased microbiota diversity and butyrate production is associated with overall host health, our findings warrant the use of exercise prescription as an adjuvant therapy in combating dysbiosis-associated diseases.Health and Social Development, Faculty of (Okanagan)Arts and Sciences, Irving K. Barber School of (Okanagan)Biology, Department of (Okanagan)Health and Exercise Sciences, School of (Okanagan)ReviewedFacult

Composition of high-fat diets.

1<p>Mineral mix (mg/g): di calcium phosphate 500, magnesium oxide 24; potassium citrate 220, potassium sulfate 52; sodium chloride 74, chromium KSO₄ 12H₂0 0.55; cupric carbonate 0.3, potassium iodate 0.01; ferric citrate 6, manganous carbonate 3.5, sodium selenite 0.01, zinc carbonate 1.6; sucrose 118.03.</p>2<p>Vitamin Mix (mg/g): vitamin A 0.8; vitamin D₃ 1; vitamin E 10; menadione sodium bisulfite 0.08; nicotinic acid 3; calcium pantothenate 1.6; pyridoxine HCl 0.7; riboflavin 0.6; thiamin 0.6; sucrose 978.42.</p>3<p>Added to meet essential fatty acid requirements for all groups.</p

ω-3 PUFA supplementation to ω-6 PUFA rich diets resulted in impaired infection-induced intestinal alkaline phosphatase activity.

<p>A) IAP+ cells were highest in ω-6 PUFA rich diet groups during infection and ω-3 PUFA supplementation impaired this response. Colon sections were stained for the presence of IAP+ cells and quantified. Representative immunofluorescence images are shown at 200× magnification (scale bar = 13.6 µm). B) While both the low and high ω-6 PUFA rich diet groups showed an induction of LPS-dephosphorylating activity during infection induced colitis, theω-3 PUFA supplementation fed mice were unable to dephosphorylate LPS in response to infection. Colonic tissues were homogenized, supernatant collected and LPS incubated with each diet group for 2 hours. A colorimetric malachite green solution was used to measure absorbance at 620 nm and the LPS-dephosphorylating activity/mg of protein was determined for each diet group. (*, <i>P</i><0.05; **, <i>P</i><0.005).</p

ω-3 PUFA supplementation to ω-6 PUFA rich diets impairs intestinal inflammatory cell infiltration during <i>C. rodentium-</i>induced colitis.

<p>While ω-6 PUFA rich diets induced the infiltration of macrophages, neutrophils and PGE2 inflammatory cells, ω-3 PUFA supplementation prevented the enhanced infiltration during infection. Colon sections were stained for the presence of submucosal A) F4/80+ macrophages B) MPO+ neutrophils and C) PGE2+ cells and quantified. Representative immunofluorescence images are shown at 200× magnification. (scale bar = 13.6 µm; *, <i>P</i><0.05).</p