Ontario Graduate Scholarship Research Articles

Sulfonylureas Compromise Microvascular Flow in Mouse Skeletal Muscle

Sulfonylureas are among the most prescribed oral anti-hyperglycaemics, particularly in low- and middle-income countries. Sulfonylureas are insulin secretagogues through blocking ATP-sensitive potassium channels (KATP) in β-cells of the pancreas. Despite wide usage, sulfonylureas are associated with increased cardiovascular disease morbidity and all-cause mortality, with ill-defined mechanisms. We tested the hypothesis that glyburide could block KATP channels in the microvasculature, thereby disrupting tissue oxygen demand-supply balance. We further investigated the contribution of other potassium channels to capillary-to-arteriole signalling. Experiments were conducted using an in-vivo anesthetized mouse skeletal muscle preparation (extensor digitorum longus, EDL); exteriorized and situated at in-situ length, overtop an oxygen-permeable membrane covering a gas chamber, and bathed in PlasmaLyte. C57BL/6 mice were employed (n=6-8). Brightfield images were captured at two wavelengths: oxygen-dependent and oxygen-independent, enabling the simultaneous determination of capillary hemodynamics and RBC oxygen content. Low oxygen challenges were achieved by dropping oxygen levels in the gas chamber from 7% to 2% for 3 minutes. Challenges were conducted before (control) and after drugs were added to bathing solution. Parameters were obtained before the challenge (baseline), during the challenge (2 regions) and after the challenge (recovery). Statistical significance was determined using a paired Student’s t-test. Target channels localization was investigated using immunofluorescence in formalin-fixed EDL. Oxygen challenges augmented EDL surface capillary hematocrit and RBC velocity and supply rate, while reducing RBC oxygen saturation. Incubation of the EDL with 10 μM glyburide decreased the baseline RBC supply rate (p<0.05 vs control) and blunted the magnitude of capillary responses to the oxygen challenge (p<0.05 vs control). Immunofluorescence confirmed the localization of KATP channels in EDL capillaries. Normal capillary responses were obtained when small and intermediate conductance or inward rectifier potassium channels were neutralized. This implies minimal or no contribution of these channels in oxygen signaling in the microvasculature. This data begins to elucidate the acute and direct effects of systemic KATP blockers on capillary-to-arteriole conducted signaling, which is likely key to optimal tissue oxygen regulation. Further experiments are warranted to confirm this conclusion. This work was supported by the Natural Science and Engineering Research Council of Canada (NSERC, RGPIN/04659-2017), an Ontario Graduate Scholarship (M.A.E) and a CIHR doctoral award (M.A.E). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Investigation of the Role of Aging on Pulmonary Microvascular Endothelial Cell Barrier Function During Mechanical Ventilation

Elderly individuals have substantially elevated morbidity and mortality following pulmonary insult that require mechanical ventilation (MV) to sustain respiratory function. It is not known if an altered response to MV contributes to the worsened outcomes in the elderly. MV is associated with injury to pulmonary microvascular endothelial cells (PMVEC), leading to a compromised vascular barrier, and fluid and protein leakage within the tissue. However, the precise impact that age has on the vascular endothelium during MV is unknown. We hypothesized that aging augments PMVEC barrier dysfunction during MV. To address this hypothesis, young and aged mice were ventilated at a tidal volume of 20 mL/kg for 3 hours. To assess microvascular permeability, lungs were lavaged and abundance of the serum protein, immunoglobulin M, within the lavage fluid was measured. Lung tissue was dissociated into single cells and RNA was collected for single-cell RNA sequencing (scRNAseq). Subsequent analysis was performed using the Seurat package in R to give insight into the role of specific cell types, with a particular emphasis on microvascular endothelial cells. To directly assess molecular mechanisms directly in the cells, PMVEC were isolated from a separate cohort of non-ventilated young and aged mice and cultured in vitro. Cells were grown to confluency, then assessed for barrier integrity by Evans blue-labelled albumin leak across monolayers and immunofluorescence staining of cell junctional adherens and tight junction proteins, VE-cadherin and claudin-5. Compared to young, aged-ventilated animals had a significant increase in immunoglobulin M in their lavage fluid. Analysis of scRNAseq data revealed more robust activation and inflammation in the endothelial cells from aged animals following MV. Endothelial monolayers from aged animals in vitro exhibited a significant increase in albumin flux, which was associated with poor VE-cadherin and claudin-5 junction formation. In conclusion, PMVEC from aged mice exhibit compromised barrier function, leading to augmented permeability following MV. The age-dependent loss in barrier function appears to be due to an impaired ability to re-establish functional cell-cell junctions. These findings suggest that the aged vascular barrier is more susceptible to injury from MV, due to impaired PMVEC cell-cell junction integrity. Our results may highlight molecular pathways involved in predisposing aged individuals to worsened outcomes during MV, which can help in developing targeted therapeutics. Funded by Lawson Health Research Institute, CIHR, the Ontario Graduate Scholarship, and Western University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Impact of chronic muscle use and disuse on innate immune signaling in skeletal muscle

Mitochondria exhibit high levels of adaptability to various stimuli such as chronic muscle use (i.e. exercise) or disuse, such as immobilization or denervation. These changes in the mitochondrial network ultimately affect the health and functioning of skeletal muscle, which contributes to whole-body metabolism, locomotion, and postural stability. It is now acknowledged that mitochondrial dysfunction can activate inflammatory pathways through the recognition of damage-associated molecular patterns (DAMPs). The objective of this study was to examine how changes in mitochondria brought about by either chronic muscle inactivity or chronic exercise training affect innate immune system activation. We hypothesized that an inverse relationship between mitochondrial content and innate immune signaling would be evident in skeletal muscle. To investigate this, skeletal muscle from the hindlimbs of mice was collected after 7 days of sciatic muscle denervation, or after 4.5 weeks of endurance swim training involving 240 minutes of daily exercise. We analyzed the expression of the NLRP3 inflammasome, innate immune system signaling proteins, mitochondrial markers, and mitochondrial DNA (mtDNA) content using western blotting, cytochrome C oxidase (COX) activity, ELISA and qPCR. Following 7 days of denervation, there was a significant decrease in both COX-IV protein and COX activity, indicating a reduction in mitochondrial content. This was accompanied by an increase (p<0.05) in NLRP3, procaspase-1, gasdermin-D (GSDMD) and its active N-terminal fragment, GSDMD-N, as well as a notable increase in IL-1β. In addition, other possible converging pathways were also upregulated including cGAS-STING, and gasdermin-E. In comparison, following exercise training, there was a significant increase in mitochondrial content, apparent through increases in COX-IV protein, COX activity and mitochondrial RNA content. This was associated with decreases in procaspase-1 and caspase-1 protein expression alongside reduced STING activation. These findings highlight an inverse relationship between mitochondrial content and the activation of several inflammatory pathways that possibly converge upon NLRP3 inflammasome activation and pyroptotic cell death, leading to detriments in skeletal muscle health. This work aims to further the understanding of innate immune signaling pathways within muscle which can potentially highlight therapeutic targets to regulate its activation under divergent metabolic conditions. This work was supported by funds from the Natural Science and Engineering Research Council (NSERC). Priyanka Khemraj is the holder of an Ontario Graduate Scholarship. David A. Hood is the holder of a Canadian Research Chair in Cell Physiology. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Validating part of the social media infodemic listening conceptual framework using structural equation modelling

The literature has identified various factors that promote or hinder people's intentions towards COVID-19 vaccination, and structural equation modelling (SEM) is a common approach to validate these associations. We propose a conceptual framework called social media infodemic listening (SoMeIL) for public health behaviours. Hypothesizing parameters retrieved from social media platforms can be used to infer people's intentions towards vaccination behaviours. This study preliminarily validates several components of the SoMeIL conceptual framework using SEM and Twitter data and examines the feasibility of using Twitter data in SEM research. A total of 2420 English tweets in Toronto or Ottawa, Ontario, Canada, were collected from March 8 to June 30, 2021. Confirmatory factor analysis and SEM were applied to validate the SoMeIL conceptual framework in this cross-sectional study. The results showed that sentiment scores, the log-numbers of favourites and retweets of a tweet, and the log-numbers of a user's favourites, followers, and public lists had significant direct associations with COVID-19 vaccination intention. The sentiment score of a tweet had the strongest relationship, whereas a user's number of followers had the weakest relationship with the intention of COVID-19 vaccine uptake. The findings preliminarily validate several components of the SoMeIL conceptual framework by testing associations between self-reported COVID-19 vaccination intention and sentiment scores and the log-numbers of a tweet's favourites and retweets as well as users' favourites, followers, and public lists. This study also demonstrates the feasibility of using Twitter data in SEM research. Importantly, this study preliminarily validates the use of these six components as online reaction behaviours in the SoMeIL framework to infer the self-reported COVID-19 vaccination intentions of Canadian Twitter users in two cities. This study was supported by the 2023-24 Ontario Graduate Scholarship.

Charging Station Location and Sizing for Electric Vehicles Under Congestion

This paper studies the problem of determining the strategic location of charging stations and their capacity levels under stochastic electric vehicle flows and charging times taking into account the route choice response of users. The problem is modeled using bilevel optimization, where the network planner or leader minimizes the total infrastructure cost of locating and sizing charging stations while ensuring a probabilistic service requirement on the waiting time to charge. Electric vehicle users or followers, on the other hand, minimize route length and may be cooperative or noncooperative. Their choice of route in turn determines the charging demand and waiting times at the charging stations and hence, the need to account for their decisions by the leader. The bilevel problem reduces to a single-level mixed-integer model using the optimality conditions of the follower’s problem when the charging stations operate as M/M/c queues and the followers are cooperative. To solve the bilevel model, a decomposition-based solution methodology is developed that uses a new logic-based Benders algorithm for the location-only problem. Computational experiments are performed on benchmark and real-life highway networks, including a new eastern U.S. network. The impact of route choice response, service requirements, and deviation tolerance on the location and sizing decisions are analyzed. The analysis demonstrates that stringent service requirements increase the capacity levels at open charging stations rather than their number and that solutions allowing higher deviations are less costly. Moreover, the difference between solutions under cooperative and uncooperative route choices is more significant when the deviation tolerance is lower. History: This paper has been accepted for the Transportation Science Special Issue on 2021 TSL Workshop: Supply and Demand Interplay in Transport and Logistics. Funding: This research was supported by the Ontario Graduate Scholarship when Ö. B. Kınay was a PhD candidate at the University of Waterloo, and this support is acknowledged. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2021.0494 .

PD31-06 THE EFFECT OF KIDNEY PRESERVATION AT 10°C WITH HEMOPURE AND HYDROGEN SULFIDE DONOR, SODIUM THIOSULFATE, IN A SYNGENEIC RAT RENAL TRANSPLANTATION MODEL

You have accessJournal of UrologyCME1 Apr 2023PD31-06 THE EFFECT OF KIDNEY PRESERVATION AT 10°C WITH HEMOPURE AND HYDROGEN SULFIDE DONOR, SODIUM THIOSULFATE, IN A SYNGENEIC RAT RENAL TRANSPLANTATION MODEL Maria Abou Taka and Alp Sener Maria Abou TakaMaria Abou Taka More articles by this author and Alp SenerAlp Sener More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003324.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Renal transplantation is the preferred treatment for patients with end-stage renal disease. Yet, donor kidney demand outweighs supply. Static cold storage (SCS) at 4°C is the current gold standard for renal preservation. SCS contributes to kidney damage through renal ischemia-reperfusion injury (IRI) that involves cellular death and inflammation. In porcine models of renal transplantation, we added non-FDA-approved hydrogen sulfide (H2S) donor, AP39, to a bovine-based blood substitute, Hemopure, at 21°C and 37°C, which improved renal graft quality; though, the experimental setup was costly to meet renal metabolic demand. In rats, we investigated sodium thiosulfate (STS), an FDA-approved H2S donor, at 4°C and observed similar benefits. However, there is still a risk of 4°C cold IRI. Recent studies showed that 10°C human organ graft preservation enhanced patient survival without requiring extensive oxygen during preservation. Therefore, we hypothesize that preservation solutions with STS and Hemopure at 10°C will reduce renal IRI compared to SCS. METHODS: Using an in vitro model of rat renal IRI, we evaluated STS use at 4°C, 10°C, 21°C, and 37°C. We treated rat proximal tubular epithelial cells with 150 µM STS for 24 hours in hypoxic conditions to mimic ischemia, and 24 hours in normoxic conditions to mimic reperfusion. To assess cellular viability, we used flow cytometry and stained cells with FITC-Annexin-V and PerCP-Propidium Iodide to determine apoptosis and necrosis levels, respectively. RESULTS: STS treatment significantly enhanced cellular viability at 10°C compared to 4°C, 21°C, and 37°C, as determined by the percentage of cells negatively stained with FITC-Annexin-V and PerCP-Propidium Iodide. STS treatment also significantly decreased apoptotic and necrotic cells at 10°C compared to 4°C, 21°C, and 37°C, as shown by the percentage of cells positively stained with FITC-Annexin-V and PerCP-Propidium Iodide. CONCLUSIONS: Overall, 10°C STS treatment significantly protects rat proximal tubular epithelial cells from IRI, suggesting that 10°C kidney preservation may enhance renal graft survival, especially in a cost-effective manner, compared to other preservation temperatures currently used in transplantation. Source of Funding: Ontario Graduate Scholarship, Department of Surgery Internal Research Funds, Lawson Internal Research Fund © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e902 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Maria Abou Taka More articles by this author Alp Sener More articles by this author Expand All Advertisement PDF downloadLoading ...

Predictors of Weight Gain in Under Five Children With Severe Acute Malnutrition: An Analysis of the Icddr, B Hospital Dataset

ObjectivesChildren admitted to hospital with severe acute malnutrition (SAM) and acute illness can be challenging to nutritionally rehabilitate. There is limited understanding on predictors of weight gain during hospitalization in this vulnerable population. This work aimed to predict the weight gain in children using anthropometric, biochemical, clinical, and socio-demographic variables.MethodsWe included 5,044 children aged 0–59 months with SAM hospitalized in the Dhaka Hospital at icddr, b between 2011 and 2019. Surveillance data was collected during hospitalization and analyzed retrospectively. The 15% weight gain from hospital admission to discharge was considered as outcome because it is recommended as the transition criteria from facility to community-based management. We trained a Random Forest classifier to identify the best set of predictors of a 15% weight gain. A total of 78 features were considered. The developed diagnostic model was validated based on the area under the curve (AUC) between the true positive and the false positive rates.ResultsThe classification of data based on the outcome (weight gain > 15%) created unbalanced classes, a larger group with < 15% changes in weight and a very small group with > 15% weight gain. To balance this data disparity, we finally included 263 children in this analysis. A model including 197 children (75% of the dataset) was identified in the training dataset, while the rest were used as a test dataset. Validation in the test dataset revealed an AUC of 69.05% when considering all 78 predictors. Among the top predictors were mid-upper arm circumference at admission, family income and breastfeeding duration.ConclusionsThis analysis revealed the role of socio-economic status as well as the importance of breastfeeding practices in attaining 15% weight gain from hospital admission to discharge in under five children treated for SAM. This finding has important implications for future work regarding childhood feeding practices and community-based detection of children with SAM.Funding SourcesJoannah and Brian Lawson Center for Child Nutrition, Ontario Graduate Scholarship, Canadian Institutes of Health Research Healthy Cities Research Initiative, and icddr, b, Dhaka, Bangladesh.

The Association between Longitudinal BMI Patterns in Children and their Parents

ObjectivesParental (maternal and paternal) weight before and after pregnancy has been associated with an increased risk of obesity in the offspring. However, less is known on the longitudinal association between parental and child growth trajectories across early childhood. This work aims to describe parental and child body mass index (BMI) trajectory patterns from birth until adolescence and assess their association.MethodsWe analyzed 1537 single-child families participating in the Applied Research Group for Kids (TARGet Kids! ) cohort (ON, Canada). Children and their parents had repeated measurements of weight and length or height from child's birth to 13 years during scheduled visits with their primary care physician. These measurements were used to calculate BMI for parents and age and sex adjusted BMI z-scores (zBMI) for children based on the World Health Organization. Latent class mixed modeling was used to identify children and parental growth patterns. A loglinear analysis was conducted to study the tri-party interaction between child, maternal, paternal longitudinal patterns. Jaccard distance was used to assess cluster similarity.ResultsWe identified two distinct patterns in children (normal, increasing obesity), mothers (normal, increasing obesity), and fathers (overweight, obesity). The three-way loglinear analysis indicated that the tri-party interaction between children, maternal and paternal growth patterns interaction was significant (χ2 (1) = 15.1, p < .001). 92.1% of children in the normal pattern had mothers in the normal pattern and fathers in the overweight pattern. Cluster similarity was 63% for mothers and children, but 12.5% between fathers and children, with most children from the increasing obesity group with a father in the overweight group.ConclusionsThere is a significant tri-party association between children, maternal and paternal BMI patterns from birth to adolescence. Future studies should aim in studying eating and other health behaviors associated with these relationships at the family level.Funding SourcesJoannah and Brian Lawson Center for Child Nutrition, Ontario Graduate Scholarship, Canadian Institutes of Health Research.

Multi-tract multi-symptom relationships in pediatric concussion.

The heterogeneity of white matter damage and symptoms in concussion has been identified as a major obstacle to therapeutic innovation. In contrast, most diffusion MRI (dMRI) studies on concussion have traditionally relied on group-comparison approaches that average out heterogeneity. To leverage, rather than average out, concussion heterogeneity, we combined dMRI and multivariate statistics to characterize multi-tract multi-symptom relationships. Using cross-sectional data from 306 previously concussed children aged 9-10 from the Adolescent Brain Cognitive Development Study, we built connectomes weighted by classical and emerging diffusion measures. These measures were combined into two informative indices, the first representing microstructural complexity, the second representing axonal density. We deployed pattern-learning algorithms to jointly decompose these connectivity features and 19 symptom measures. Early multi-tract multi-symptom pairs explained the most covariance and represented broad symptom categories, such as a general problems pair, or a pair representing all cognitive symptoms, and implicated more distributed networks of white matter tracts. Further pairs represented more specific symptom combinations, such as a pair representing attention problems exclusively, and were associated with more localized white matter abnormalities. Symptom representation was not systematically related to tract representation across pairs. Sleep problems were implicated across most pairs, but were related to different connections across these pairs. Expression of multi-tract features was not driven by sociodemographic and injury-related variables, as well as by clinical subgroups defined by the presence of ADHD. Analyses performed on a replication dataset showed consistent results. Using a double-multivariate approach, we identified clinically-informative, cross-demographic multi-tract multi-symptom relationships. These results suggest that rather than clear one-to-one symptom-connectivity disturbances, concussions may be characterized by subtypes of symptom/connectivity relationships. The symptom/connectivity relationships identified in multi-tract multi-symptom pairs were not apparent in single-tract/single-symptom analyses. Future studies aiming to better understand connectivity/symptom relationships should take into account multi-tract multi-symptom heterogeneity. Financial support for this work came from a Vanier Canada Graduate Scholarship from the Canadian Institutes of Health Research (G.I.G.), an Ontario Graduate Scholarship (S.S.), a Restracomp Research Fellowship provided by the Hospital for Sick Children (S.S.), an Institutional Research Chair in Neuroinformatics (M.D.), as well as a Natural Sciences and Engineering Research Council CREATE grant (M.D.).

Tandem cardiovascular system modelling and machine learning for improved heart failure phenotyping.

Tandem cardiovascular system modelling and machine learning for improved heart failure phenotyping.

Greater Adherence to the Portfolio Diet Is Associated with Lower Incidence of Type 2 Diabetes in the Women’s Health Initiative

ObjectivesTo assess the association of the plant-based cholesterol-lowering diet, the Portfolio Diet, with incident type 2 diabetes in women. MethodsWe followed 147,732 postmenopausal women initially free of diabetes in the Women’s Health Initiative (WHI) Clinical Trials and Observational Study from 1993 through 2017. Adherence to the Portfolio Diet was assessed using an a priori diet index based on six food categories (high in plant protein [soy & pulses], nuts, viscous fiber, plant sterols and monounsaturated fat, and low in saturated fat) that were previously found to lower cardiovascular risk factors in the Portfolio Diet trials. We used Cox proportional-hazard models to estimate hazard ratios (HRs) and 95% confidence intervals (CI) of the association of adherence to a Portfolio Diet score with incident type 2 diabetes, adjusting for potential confounders (demographics, lifestyle behaviors, and medical history). The Portfolio Diet score was cumulatively assessed at baseline and year three using a validated food frequency questionnaire. Type 2 diabetes diagnosis was ascertained by self-reported medication use. ResultsThere were 14,096 cases of incident type 2 diabetes over a mean follow-up of 14.3 years. In the fully adjusted models, adherence to the Portfolio Diet score was associated with a lower risk of incident type 2 diabetes (HR, 0.88, CIs, 0.83, 0.93; P for trend < 0.001), comparing the highest to lowest quartiles of adherence. Results remained similar across subgroup analyses (age, body mass index, family history of diabetes, and ethnicity) and several sensitivity analyses. ConclusionsAmong postmenopausal women, higher adherence to the Portfolio Diet was associated with lower incident type 2 diabetes. These findings are the first to show that the Portfolio Diet may be associated with a lower risk of type 2 diabetes and warrants further investigation. Funding SourcesThe WHI was funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, and the U.S. Department of Health and Human Services. AJG was supported by the Banting & Best Diabetes Centre Tamarack Graduate Award in Diabetes Research, the Peterborough K.M. Hunter Charitable Foundation Graduate Award, and an Ontario Graduate Scholarship. JLS was funded by a Diabetes Canada Clinician Scientist Award.

Plant-Based Dietary Patterns and Cardiometabolic Risk: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

Abstract Objectives Plant-based diets defined by limited animal food consumption have been extensively associated with cardiometabolic health benefits in Western nations. Diet indices are increasingly used to distinguish the protective characteristics of a plant-based diet at different levels of adherence. We aimed to synthesize evidence on the association between adherence to plant-based diet indices and cardiometabolic risk. A plant-based diet index (PDI) is hypothesized to be inversely associated with type 2 diabetes (T2D) and cardiovascular disease (CVD) with a stronger association with the healthful index (hPDI) that emphasizes higher quality plant-based foods. Methods We systematically searched MEDLINE, EMBASE and CINAHL databases through January 2021. Prospective cohort studies assessing the association of plant-based diet indices with T2D and CVD in adults were included and appraised for risk of bias and quality (NutriGrade). We followed the PRISMA-P, Cochrane and MOOSE guidelines. Random and fixed-effects meta-analyses were conducted to pool risk ratios (RR) of extreme quantiles. Dose-response meta-analyses were conducted after harmonizing all diet index scores. I2-values of 30–60%, 50–90%, and 75–100% denoted moderate, substantial, and considerable heterogeneity respectively. Results We included a total of 10 studies from 5927 retrievals. Across 6 studies there were 22 135 cases of T2D over 4 817 308 person-years. Across 7 studies there were 15 077 cases of CVD over 6 117 016 person-years. The PDI was associated with a lower risk of T2D (RR = 0.82, 95% CI [0.75, 0.91], I2 = 55.4%), and CVD (RR = 0.88, 95% CI [0.8, 0.96], I2 = 16.2%). The hPDI had a stronger inverse association with T2D (RR = 0.73, 95% CI [0.68, 0.77], I2 = 84.3%) and CVD (RR = 0.8, 95% CI [0.77, 0.88], I2 = 55.9%). All dose-response relationships were linear (except hPDI with CVD). All studies had acceptable risk of bias and the quality of evidence was moderate. Conclusions Adherence to a plant-based diet was inversely associated with T2D and CVD with a stronger association for a healthful plant-based diet pattern. Since highest quantiles of the index still included moderate meat consumption, linear dose-responses emphasized potential benefits on risk of T2D and CVD with any incremental progression towards a plant-based diet. Funding Sources Nora Martin Fellowship, Ontario Graduate Scholarship.

245 Sleep and cortical thickness are influenced by surgical menopause

Abstract Introduction Early loss of 17β-estradiol (E2), as experienced by women with bilateral salpingo-oophorectomy (BSO; removal of ovaries and fallopian tubes), is associated with increased prevalence of sleep disorders and greater Alzheimer’s disease (AD) risk. In older adults, poor sleep heightens AD risk; hypoxia increases markers for incipient AD, including circulating Aβ, and is linked to prefrontal cortical thinning. Thus, we wondered: 1) if this at-risk population of middle-aged women with BSO had sleep hypoxia, measured by oxygen desaturation, and 2) whether this related to decreased prefrontal cortical thickness in women taking and not taking estradiol therapy (ET). Methods Sleep and percent oxygen desaturation (SPO2%) were measured via at-home polysomnography (TEMEC). Prefrontal cortical thickness was obtained from T1-weighted structural scans using the CIVET pipeline. We recruited middle-age women with BSO, some of whom were taking ET (BSO+ET; n=15), and some not (BSO; n=15). We compared their sleep and cortical thickness with that of age and education-matched premenopausal controls (AMC; n=18). Results Women with BSO (BSO, BSO+ET) had lower minimum SPO2% values than AMC, and thinner right medial orbitofrontal (rmOF) cortices. There was a trend for women with BSO to have lower average SPO2% than AMC. Analyses separating groups based on ET therapy status (BSO vs BSO+ET vs AMC) revealed only trending differences between groups, such that women with BSO tended to have lower minimum SPO2% and thinner rmOF cortices than AMC. Conclusion These preliminary results suggest early loss of E2 due to BSO may drive greater drops in SPO2% in middle-age women, and may be related to reduced prefrontal cortical thickness. This study is the first to show hypoxia in women with BSO. Support (if any) Ontario Graduate Scholarship Award (to LG), Alzheimer’s Association Research Fellowship (co-sponsored by Brain Canada Foundation; AARF-17-504715 to NJG), Alzheimer’s Society Canada Postdoctoral Fellowship (to AA), Canadian Institutes of Health Research (CIHR) Masters Award (to LG, AB, and RR), Wilfred and Joyce Posluns Chair in Women’s Brain Health and Aging (from the Posluns Family Foundation, CIHR, Ontario Brain Institute, and Alzheimer Society of Canada; WJP-150643 to GE)

Intramuscular adipose tissue: a cause for concern.

Intramuscular adipose tissue: a cause for concern.

Numeric and Traffic Light Calorie Labels on Cafeteria Menus: Noticing, Use, and Perceptions Among Young Adults

Abstract Objectives The objective of this study was to examine the impact of numeric versus interpretive calorie labelling on consumer noticing, use, and perceptions of labels. We hypothesized that due to their at-a-glance format, interpretive labels would outperform numeric labels. Methods Using a pre-post quasi-experimental controlled trial design, three campus cafeterias were randomized to receive numeric calorie labelling, traffic light labelling (i.e., red, amber, or green symbol indicating the number of calories), or no labelling for two weeks. Exit surveys were conducted with cafeteria patrons prior to (n = 949) and following (n = 1110) implementation of labels. Surveys queried sociodemographic characteristics, the details of the most recent cafeteria purchase, and noticing, use, and perceptions of labels. Chi-squared tests and multinomial logistic regression were used to determine the impact of format on label noticing, use, and perceptions. Results Label noticing increased from 23% to 43% among those exposed to numeric labels and 28% to 63% among those exposed to traffic light labels, compared to no change in the control (15%) (P &amp;lt; 0.05). Among those who noticed labels, a higher proportion (66%) of those in the traffic light condition reported using the labels to inform their purchase compared to the numeric (50%) and control (50%) conditions (P &amp;lt; 0.05). Scores for perceived ease of use and understanding of the labels were high at both labelling sites. Compared to the pre-test period, there was a slight increase (6%) in the proportion of people who indicated traffic light labels were easy to use and understand versus no change in perceptions at the numeric and control sites (P &amp;gt; 0.05). Conclusions Cafeteria patrons exposed to calorie labels reported noticing and using them, with higher salience for traffic light labels. The implementation of such interpretive labels at the point-of-purchase may provide cues to enable consumers to make informed choices, consistent with front-of-pack labels on packaged foods under consideration in many jurisdictions. Funding Sources Kirsten Lee is funded by an Ontario Graduate Scholarship. This study is funded by the Canadian Foundation for Dietetic Research and an Ontario Ministry of Research and Innovation Early Researcher Award held by Sharon Kirkpatrick.

Gluten-Free Claims Are Displayed Mostly on Processed and Ultra-Processed Foods in Canada

Abstract Objectives Celiac disease is an autoimmune condition characterized by an adverse response to gluten ingestion. While only 1% of the population must follow a gluten-free diet (e.g., those with celiac disease), gluten-free products are becoming increasingly prevalent in Canada, particularly among packaged products, which are largely processed or ultra-processed. Yet, excess consumption of processed and ultra-processed foods has been associated with poor diet quality, a risk factor for obesity and other non-communicable diseases. Objectives To examine whether the presence of gluten-free claims (GFC) on packaged food and beverage products was associated with level of processing. Methods Cross-sectional analysis of the University of Toronto Food Label Information Program 2017. GFC were identified by systematically reviewing the photographs of food labels (n = 17,267). Products were classified into 22 main food categories as determined by the Health Canada's Table of Reference Amounts for Foods. Using the NOVA food processing classification system, products were also classified into two groups: 1) Unprocessed or minimally processed and processed culinary ingredients; and 2) processed or ultra-processed. Proportions of products displaying GFC were calculated overall, by food category and by level of processing. Binomial logistic regression models examined the association of GFC with level of processing. Results Fifteen % of products displayed GFC. Categories displaying the largest proportion of GFC were snacks (32%), meat and poultry products (28%), and nuts and seeds (26%). The presence of GFC claim was associated with foods being processed or ultra-processed (β = 1.63, P &amp;lt; 0.001). In 8 of the 22 food categories, 100% of products displaying GFC were processed or ultra-processed, while more than 80% of foods displaying GFC in 17 of 22 categories were considered processed or ultra-processed. Conclusions About 1/6 of prepackaged foods and beverages displayed gluten-free claims in the Canadian Food supply. Most of them were considered processed and ultra-processed foods. Funding Sources Canadian Institutes of Health (CIHR) Scholarships [BFA, LV], Department of Nutritional Sciences Graduate Student Fellowship [BFA; LV], Ontario Graduate Scholarship [LV], CIHR Research Grant 2016PJT-152,979 [MRL].

Epinephrine Responsiveness is Reduced in Livers from Trained Mice

Catecholamines increase liver glucose production at least in part through increases in glycogenolysis and gluconeogenesis. To date, the effects of prior exercise training on the liver’s response to epinephrine, in vivo, have not been fully elucidated. To examine the role of epinephrine signaling on indices of liver glucose production in trained mice, male C57BL/6 mice were subject to either 12 days of voluntary wheel running (TR) or remained sedentary (SED). Epinephrine (0.5 mg/kg body weight), or vehicle were injected intraperitoneally following 12 days of training and tissues harvested 15 minutes post‐injection. The rise in blood glucose following epinephrine injection was significantly blunted in trained compared to sedentary mice and this was paralleled by a blunted reduction in liver glycogen in trained mice. There was a main effect of epinephrine to increase the phosphorylation of protein kinase‐A substrates (pPKAs), which was driven by increases in the sedentary, but not trained, mice. Similarly, epinephrine‐induced increases in the mRNA expression of α‐ and β‐adrenergic receptor 1 and 2 and glucose‐6‐phosphatase were greater in SED compared to TR mice. Exercise and epinephrine decreased serum insulin levels and increased glucagon levels, however, there were no differences within epinephrine treated groups. Changes in phosphorylated AKT, AMPK, and phosphodiesterase 4B protein content, negative regulators of PKA signaling, do not explain the protective effects of exercise training against epinephrine induced increases in blood glucose and liver glycogen breakdown. Taken together our data suggest that prior exercise training reduces the liver’s response to epinephrine. This could be beneficial in the context of training‐induced sparing of glycogen during exercise.Support or Funding InformationThis work was funded, in part, through a National Sciences and Engineering Research Council of Canada (NSERC) grant to D.C.W., who is a Tier II Canada Research Chair in Lipids, Metabolism, and Health. H.A.D was supported by an Ontario Graduate Scholarship. G.L.M. was supported by an Ontario Graduate Scholarship and subsequently an NSERC Canada Graduate Scholarship. L.K.T. was supported by a Dairy Farmers of Ontario Doctoral Research Assistantship and an NSERC Postgraduate Scholarship.

Effects of maltreatment on cortisol and inflammatory analytes

Adverse childhood experiences (ACEs) such as maltreatment have been associated with a disease risk phenotype that is characterized by altered regulation of the hypothalamic‐pituitary‐axis (HPA) and elevated pro‐inflammatory cytokines. However, there is evidence that different subtypes of ACEs elicit different physiological profiles. More specifically children with a history of physical abuse have lower cortisol levels whereas children with a history of sexual abuse have elevated cortisol levels compared to those in other maltreatment and non‐abused subgroups. The objective of the present study was to investigate if different maltreatment exposures, specifically physical and sexual abuse, are associated with HPA axis and inflammation by measuring levels of cortisol and inflammatory analytes. This study examines 156 young adults using the pilot data from the Niagara Longitudinal Heart Study (NLHS). Inflammatory analytes were assessed with blood serum. Retrospective chronic cortisol was measured through hair taken from the back of the scalp. Maltreatment was self‐reported using the Childhood Trust Event survey questionnaire. The NLHS study was approved by the Brock University’s Research Ethic Board. All analysis of variance models were not statistically significant. Those who reported sexual abuse had the highest cortisol levels. Those who reported physical abuse had the lowest cortisol levels compared to other subtypes. Interleukin 6 (IL6), C‐reactive protein (CRP), tumor necrosis factor α (TNFα), soluble tumor necrosis factor receptor 1 and 2 (sTNFR1 and sTNFR2) levels were higher among those with physical and sexual exposure compared to other subtypes. Levels of interleukin 6 receptor α (IL6Rα), glycoprotein (gp130), and interferon γ (IFNγ) were similar across all subtypes. The direction of cortisol levels pertaining to the subtypes of ACEs in the present study was consistent with the literature where physical abuse was linked to lower cortisol levels and sexual abuse was related to higher cortisol levels. Both physical and sexual abuse were trending towards statistical significance to some inflammatory analytes but not others. As the current pilot sample is underpowered for the effect sizes of cortisol and inflammatory analytes, the models used in analysis are likely to achieve statistical significance in a larger sample.Support or Funding InformationThe NLHS is funded by the Canadian Institutes of Health Research (CIHR #s 363774, 399332). ARRM is supported by the Ontario Graduate Scholarship (OGS) program.

The Role of AMPK in Neuromuscular Junction Biology

The neuromuscular junction (NMJ) is the signaling apparatus between a motoneuron and the corresponding muscle fibers that it innervates. While its stability is vital for the neuromuscular system, the NMJ is susceptible to remodeling across the lifespan. Adenosine monophosphate‐activated protein kinase (AMPK) is a primary modulator of skeletal muscle phenotype, however the precise role of AMPK at the NMJ has yet to be investigated. Thus, the purpose of this study was to examine the role of skeletal muscle AMPK on NMJ biology across the lifespan. We employed 3‐ and 12‐month‐old muscle specific AMPKβ1β2 knock out mice (mKO, n = 3), age‐matched wild‐type (WT, n = 3) mice, as well as 22‐month‐old WT animals. Extensor digitorum longus (EDL) and soleus (SOL) muscles were dissected to represent fast glycolytic and slow oxidative tissues, respectively. These muscles were then whole‐mounted and immunolabelled for presynaptic neurofilament and synaptic vesicle 2A proteins, as well as postsynaptic acetylcholine receptors (AChR) revealed by □‐bungarotoxin. Approximately 25 NMJ images per muscle were acquired via confocal microscopy. In total, we conducted 3D analysis on over 400 NMJs to determine metrics of NMJ morphology. Postsynaptic analyses revealed an effect of age (p &lt; 0.05) on the total amount of fragmented and ectopic NMJs in the SOL and EDL muscles of WT animals. Interestingly, mKO animals exhibited a significantly greater count of fragmented and ectopic NMJs in the SOL and EDL muscles, compared to their WT littermates. In fact, NMJs positive for postsynaptic abnormalities in EDL muscles of 12‐month‐old mKO animals were significantly greater than 22‐month‐old WT animals (p &lt; 0.05), while SOL muscles were comparable. An effect of age (p &lt; 0.05) on axonal blebbing and sprouting was observed in the EDL and SOL muscles, respectively. Additionally, NMJs with axonal blebbing were observed more frequently (p &lt; 0.05) in the mKO animals compared to their age‐matched WT littermates. Quantitative real‐time PCR was also utilized to examine genes important for NMJ development and maintenance in the tibialis anterior muscles of 3‐month‐old WT and mKO animals (n = 10). Specifically, AChR□/ɣ, low‐density lipoprotein receptor‐related protein 4, rapsyn, and muscle‐specific kinase mRNA expression was significantly higher in the mKO animals relative to their WT counterparts. Our results suggest that AMPK is critical to the determination and maintenance of a healthy pre‐ and post‐synaptic apparatus in motoneurons and muscles of disparate phenotypes. Additionally, the loss of muscle‐specific AMPK exacerbates age‐induced postsynaptic alterations in faster, and more glycolytic muscle fibers.Support or Funding InformationCanadian Institutes of Health Research, Canada Research Chairs, and Ontario Graduate Scholarship.

Maternal Immune Activation Alters Placental and Fetal Brain Amino Acid Transport in Rats

ProblemMaternal immune activation (MIA) during pregnancy is an environmental risk factor for neurodevelopmental disorders such as autism and schizophrenia. However, the exact mechanism through which this occurs is unknown. Due to the important roles that amino acids play in neurodevelopment, altered transport of amino acids across the placenta and throughout the developing fetal brain could play a role in neurodevelopmental disorders. Our objectives were to determine whether virally mediated MIA alters amino acid transporter expression in the placenta and fetal brain, and to explore the underlying mechanism(s) associated with these changes.MethodsPregnant rats received poly(I:C) on gestational day 14 and placental and fetal tissues were collected 6, 24, and 48 hours later. Amino acid transporter expression in the placenta and fetal brain was measured using qPCR and immunoblotting. Free amino acid concentrations in the fetal brain were quantified using HPLC. To explore a possible mechanism, the expression and phosphorylation of components of the placental mTOR and AMPK signaling pathways were investigated using immunoblotting.ResultsPoly(I:C) induced the mRNA expression of multiple amino acid transporters in the placenta and fetal brain over all three timepoints. Conversely, poly(I:C) significantly decreased protein expression of ASCT1 and EAAT2 in the placenta, and SNAT5, EAAT1, and GLYT1 in the fetal brain. Changes in transporter expression were accompanied by functional changes in the concentrations of numerous amino acids in the fetal brain. We observed activation of AMPK and inhibition of mTOR signaling in the placentas of poly(I:C)‐treated dams.ConclusionsMIA induced by poly(I:C) significantly alters placental and fetal brain amino acid transporter expression as well as amino acid concentrations in the fetal brain. Due to the importance of amino acids in neurodevelopment, changes in amino acid transporters could contribute to the development of a neurodevelopmental disorder. AMPK and mTOR have been previously shown to regulate amino acid transporter expression. Since poly(I:C) altered the activation of placental and AMPK and mTOR, these could provide novel treatment targets to alleviate MIA‐induced changes in amino acid transport and investigate the implications of these changes in neurodevelopment.Support or Funding InformationThis work was supported by an operating grant from the Canadian Institutes of Health Research (CIHR) awarded to Dr. Piquette‐Miller [MOP 13346]. Eliza McColl was a recipient of a CIHR Canadian Graduate Scholarship (Master’s) and an Ontario Graduate Scholarship, and is currently funded by a CIHR Banting and Best Canadian Graduate Scholarship (Doctoral) [GSD‐164238].