A 12-Week Pilot Exercise Program for Inactive Adults With Celiac Disease: Study Protocol

Background

Individuals with celiac disease must follow a strict gluten-free diet (GFD) in order to avoid negative short- and long-term health consequences. Unfortunately, many people with celiac disease report poor quality of life (QoL) despite following a strict GFD, and up to 30% still report negative symptoms (eg, gastrointestinal upset).

Purpose

The purpose of the MOVE-C (understanding the relationship between the MicrobiOme, Vitality, and Exercise in Celiac disease) pilot study is to explore the effects of a 12-week supervised progressive high-intensity interval training (HIIT) and lifestyle intervention on physiological, behavioral, and psychosocial outcomes among inactive adults with celiac disease.

Methods/Design: Sixty inactive adults diagnosed with celiac disease will be randomized to HIIT+ or waitlist control (WLC). Participants in the HIIT+ will engage in a 12-week HIIT + lifestyle education program. HIIT sessions will be comprised of 2 workouts per week, working up to 14 × 30-second intervals at 90% maximal heart rate (HRmax) followed by 2 minutes recovery at 50% HRmax. The 6 biweekly lifestyle sessions will involve education on the promotion of a whole foods GFD, sleep hygiene, psychosocial coping skills (eg, self-compassion), and self-regulatory skills to master changes in behaviors. Assessments will occur at pre and post 12-week intervention and 3-month follow-up. WLC participants will be offered a 12-week HIIT program + online lifestyle education sessions after completing the final assessment. The primary outcomes are QoL and gut microbiota composition assessed with 16S rRNA sequencing. The secondary outcomes are markers of metabolic syndrome (waist circumference, fasting glucose, serum lipids, blood pressure, and body composition), gastrointestinal symptoms, sleep quality, adherence to a GFD, exercise behavior, self-regulatory efficacy, and self-compassion. It is hypothesized that participants in the HIIT+ will experience improvements in all outcomes when compared to those in the WLC. These improvements are expected to be maintained at the 3-month follow-up.

Discussion

The findings from this study will advance the knowledge regarding the effects of HIIT and lifestyle education on key outcomes for an at-risk chronic disease population. Furthermore, the findings can be used to inform future programs to improve fitness and physical and mental health outcomes for people with celiac disease.

Low-Dose Stevia (Rebaudioside A) Consumption Perturbs Gut Microbiota and the Mesolimbic Dopamine Reward System

Stevia is a natural low-calorie sweetener that is growing in popularity in food and beverage products. Despite its widespread use, little is understood of its impact on the gut microbiota, an important environmental factor that can mediate metabolism and subsequent obesity and disease risk. Furthermore, given previous reports of dysbiosis with some artificial low-calorie sweeteners, we wanted to understand whether prebiotic consumption could rescue potential stevia-mediated changes in gut microbiota. Three-week old male Sprague-Dawley rats were randomized to consume: (1) Water (CTR); (2) Rebaudioside A (STV); (3) prebiotic (PRE); (4) Rebaudioside A + prebiotic (SP) (n = 8/group) for 9 weeks. Rebaudioside was added to drinking water and prebiotic oligofructose-enriched inulin added to control diet (10%). Body weight and feces were collected weekly and food and fluid intake biweekly. Oral glucose and insulin tolerance tests, gut permeability tests, dual X-ray absorptiometry, and tissue harvest were performed at age 12 weeks. Rebaudioside A consumption alone did not alter weight gain or glucose tolerance compared to CTR. Rebaudioside A did, however, alter gut microbiota composition and reduce nucleus accumbens tyrosine hydroxylase and dopamine transporter mRNA levels compared to CTR. Prebiotic animals, alone or with Rebaudioside A, had reduced fat mass, food intake, and gut permeability and cecal SCFA concentration. Adding Rebaudioside A did not interfere with the benefits of the prebiotic except for a significant reduction in cecal weight. Long-term low-dose Rebaudioside A consumption had little effect on glucose metabolism and weight gain; however, its impact on gut microbial taxa should be further examined in populations exhibiting dysbiosis such as obesity.

The mechanical and biochemical properties of tail tendon in a rat model of obesity: Effect of moderate exercise and prebiotic fibre supplementation

The worldwide trajectory of increasing obesity rates is a major health problem precipitating a rise in the prevalence of a variety of co-morbidities and chronic diseases. Tendinopathy, in weight and non-weight bearing tendons, in individuals with overweight or obesity has been linked to metabolic dysfunction resulting from obesity. Exercise and dietary fibre supplementation (DFS) are common countermeasures to combat obesity and therefore it seems reasonable to assume that they might protect tendons from structural and mechanical damage in a diet-induced obesity (DIO) model. The purpose of this study was to determine the effects of a DIO, DIO combined with moderate exercise, DIO combined with DFS (prebiotic oligofructose), and DIO combined with moderate exercise and DFS on the mechanical and biochemical properties of the rat tail tendon. Twenty-four male Sprague-Dawley rats, fed a high-fat/high-sucrose diet were randomized into a sedentary, a moderate exercise, a DFS, or a moderate exercise combined with DFS group for 12 weeks. Additionally, six lean age-matched animals were included as a sedentary control group. DIO in combination with exercise alone and with exercise and DFS reduced the Young's Modulus but not the collagen content of the rat tail tendons compared to lean control animals. However, no differences in the mechanical and biochemical properties of the rat tail tendon were detected between the DIO and the lean control group, suggesting that DIO by itself did not impact the tail tendon. It seems that longer DIO exposure periods may be needed to develop overt differences in our DIO model.

Protective effect of prebiotic and exercise intervention on knee health in a rat model of diet-induced obesity

Obesity, and associated metabolic syndrome, have been identified as primary risk factors for the development of knee osteoarthritis (OA), representing nearly 60% of the OA patient population. In this study, we sought to determine the effects of prebiotic fibre supplementation, aerobic exercise, and the combination of the two interventions, on the development of metabolic knee osteoarthritis in a high-fat/high-sucrose (HFS) diet-induced rat model of obesity. Twelve-week-old male Sprague-Dawley rats were randomized into five groups: a non-exercising control group fed a standard chow diet, a non-exercising group fed a HFS diet, a non-exercising group fed a HFS diet combined with prebiotic fibre supplement, an exercise group fed a HFS diet, and an exercise group fed a HFS diet combined with prebiotic fibre supplement. Outcome measures included knee joint damage, percent body fat, insulin sensitivity, serum lipid profile, serum endotoxin, serum and synovial fluid cytokines and adipokines, and cecal microbiota. Prebiotic fibre supplementation, aerobic exercise, and the combination of the two interventions completely prevented knee joint damage that is otherwise observed in this rat model of obesity. Prevention of knee damage was associated with a normalization of insulin resistance, leptin levels, dyslipidemia, gut microbiota, and endotoxemia in the HFS-fed rats.

Impact of dietary fiber supplementation on modulating microbiota-host-metabolic axes in obesity

Low dietary fiber intake is associated with higher rates of microbiota-associated chronic diseases such as obesity. Low-fiber diets alter not only microbial composition but also the availability of metabolic end products derived from fermentation of fiber. Our objective was to examine the effects of dietary fiber supplementation on gut microbiota and associated fecal and serum metabolites in relation to metabolic markers of obesity. We conducted a 12-week, single-center, double-blind, placebo-controlled trial with 53 adults with overweight or obesity. They were randomly assigned to a pea fiber (PF, 15 g/d in wafer form; n=29) or control (CO, isocaloric amount of wafers; n=24) group. Blood and fecal samples were collected at baseline and 12 weeks. Serum metabolomics, gut microbiota and fecal short-chain fatty acids (SCFAs) and bile acids (BAs) were examined. Within-group but not between-group analysis showed a significant effect of treatment on serum metabolites at 12 weeks compared to baseline. Fiber significantly altered fecal SCFAs and BAs with higher acetate and reduced isovalerate, cholate, deoxycholate and total BAs content in the PF group compared to baseline. Microbiota was differentially modulated in the two groups, including an increase in the SCFA producer Lachnospira in the PF group and decrease in the CO group. The change in body weight of participants showed a negative correlation with their change in Lachnospira (r=-0.463, P=.006) abundance. The current study provides insight into the actions of pea fiber and its impact on modulating microbiota-host-metabolic axes in obesity.

Metabolic consequences of discretionary fortified beverage consumption containing excessive vitamin B levels in adolescents

Over the past decade, there has been a substantial increase in the number of beverage products containing added vitamins and minerals. Often viewed as a healthier choice by consumers, the metabolic impacts of excessive vitamin consumption are relatively unknown, especially in children. The aim of this study was to examine the effects of a widely available, vitamin fortified beverage (5h Energy Decaffeinated) on insulin sensitivity, metabolic hormones and serum metabolomic responses in adolescents. Twenty adolescents (13-19y, 10M/10F) completed two randomized trials, consuming either coloured water as placebo (PL) or a vitamin fortified, sugar free beverage (FB, 1.5ml/kg) 40min prior to a modified oral glucose tolerance test (OGTT, 1.75g/kg glucose). Samples were collected at baseline and at 30, 45, 60, 90 and 120min during the OGTT. No differences in blood glucose response were observed between the treatments. However, compared to PL, postprandial plasma C-peptide and insulin excursion was significantly greater with FB, resulting in a 28% decline in the insulin sensitivity index. This was accompanied by elevated GLP-1, glucagon and PYY responses with FB compared to PL. Serum metabolomics (¹H-NMR) analysis also revealed perturbations to vitamin B-linked one carbon metabolism flux with FB consumption that became more pronounced over time. These included a transient reduction in homocysteine flux accompanied by increases in betaine, vitamin B6, vitamin B12, choline, folate and taurine. Although these impacts are likely short-lived, results show that beverages fortified with excessive amounts of vitamins are not metabolically inert, but likely result in greater insulin secretion, differential gut hormone secretion and elevated one-carbon flux to process the excessive vitamin loads.

Maternal prebiotic supplementation reduces fatty liver development in offspring through altered microbial and metabolomic profiles in rats

A maternal high-fat/sucrose diet, in the presence of maternal obesity, can program increased susceptibility to obesity and metabolic disease in offspring. In particular, nonalcoholic fatty liver disease risk is associated with poor maternal nutrition and obesity status, which may manifest via alterations in gut microbiota. Here, we report that in a preclinical model of diet-induced maternal obesity, maternal supplementation of a high-fat/sucrose diet with the prebiotic oligofructose improves glucose tolerance, insulin sensitivity, and hepatic steatosis in offspring following a long-term high-fat/sucrose dietary challenge compared with offspring of untreated dams. These improvements are associated with alterations in gut microbial composition and serum inflammatory profiles in early life and improvements in inflammatory and fatty-acid gene expression profiles in tissues. Serum metabolomics analysis highlights potential metabolic links between the gut microbiota and the degree of steatosis, including alterations in 1-carbon metabolism. Overall, our data suggest that maternal prebiotic intake protects offspring against hepatic steatosis and insulin resistance following 21 wk of high fat/sucrose diet, which is in part due to alterations in gut microbiota.-Paul, H. A., Collins, K. H., Nicolucci, A. C., Urbanski, S. J., Hart, D. A., Vogel, H. J., Reimer, R. A. Maternal prebiotic supplementation reduces fatty liver development in offspring through altered microbial and metabolomic profiles in rats.

Cross-Sectional Analysis of Overall Dietary Intake and Mediterranean Dietary Pattern in Patients with Crohn's Disease

The primary objective of this study was to explore the macro- and micro-nutrient intakes and dietary patterns of patients with Crohn's disease (CD). Secondary objectives were to (a) compare the micronutrient intakes of CD patients with a representative sample of individuals, (b) describe the macro- and micronutrient intakes of male and female CD patients, and (c) describe Mediterranean diet scores (P-MDS) of male and female CD patients in remission that were recruited from an inflammatory bowel disease (IBD) clinic in Calgary, AB. Consecutive patients with ileal and/or colonic CD in endoscopic remission were recruited for participation in this cross-sectional study. Sixty-seven patients were enrolled with a mean age of 45, and a Body Mass Index (BMI) ≥ 25. Compared with the representative sample, patients with CD had similar energy, protein, carbohydrate, and total fat intake. However, polyunsaturated fats (PUFA), omega-6 and 3, and monounsaturated fats (MUFA) were lower in CD patients and dietary fiber intake was higher (p < 0.05). Vitamins C, D, thiamin, niacin, magnesium, phosphorus, zinc, and potassium were all significantly lower in all CD patients when compared to the representative sample (p < 0.05). Few patients with CD met the P-MDS criteria and overall scores were low (mean 4.5, Standard Deviation (SD) = 1.1 in males and 4.7, SD = 1.8 in females). The CD patients in this study had suboptimal dietary intakes and patterns and these data may be used to inform future dietary interventions in this population to improve intake.

Impact of Food Ingredients (Aspartame, Stevia, Prebiotic Oligofructose) on Fertility and Reproductive Outcomes in Obese Rats

OBJECTIVE

This study aimed to investigate the interaction between obesity, low-calorie sweeteners, and prebiotic oligofructose on reproductive parameters in rats.

METHODS

Data were derived from two separate studies of female Sprague-Dawley rats with (1) Lean (n = 24), (2) Obese (n = 27), (3) Obese+Aspartame (n = 14), (4) Obese+Stevia (n = 15), and (5) Obese+Prebiotic (n = 15) groups. Obesity was induced with a high-fat/high-sucrose diet prior to pregnancy. In one study, human-approved doses of aspartame (5-7 mg/kg/d) and stevia (2-3 mg/kg/d) in drinking water were examined, and in the second, 10% prebiotics (oligofructose) in the diet was examined. Reproductive parameters, including fertility, pregnancy, and delivery indexes, were analyzed.

RESULTS

Obesity significantly reduced pregnancy index in Obese dams (60.7% successful pregnancies) compared with lean (100%). Obesity also reduced the number of pups born alive and pup survival percentage compared with those of Lean dams (P < 0.001). Only 53.3% of rats were able to conceive in the Obese+Stevia group, but if rats did become pregnant, they had 100% pregnancy and delivery index. While prebiotic administration rescued the pregnancy index, it could not remediate pup survival percentage (P = 0.025) in Obese dams.

CONCLUSIONS

Both obesity status and dietary ingredients affect the ability to conceive. Future rigorously controlled studies designed to examine reproductive outcomes in depth are needed to confirm these findings.

Comparison of Glucose and Satiety Hormone Response to Oral Glucose vs. Two Mixed-Nutrient Meals in Rats

The obesity epidemic is driving interest in identifying strategies that enhance appetite control by altering the secretion of hormones that regulate satiety and food intake. An appropriate nutrient stimulus, such as a meal or oral nutrient solution, is needed to elicit the secretion of satiety hormones in order to evaluate the impact of dietary and other interventions. Our objective was to compare the effects of oral glucose vs. mixed nutrients on plasma concentrations of glucose and appetite-regulating hormones to determine the most appropriate oral nutrient challenge to trigger robust hormone secretion. A 120 min oral glucose tolerance test (OGTT) was compared with two meal tolerance tests (MTT) of differing formulation to evaluate glucose and satiety hormone responses. Following overnight feed deprivation, male Sprague-Dawley rats were given one of three oral gavages with equal carbohydrate content (2 g CHO/kg) in the form of: (1) Dextrose, (2) Ensure®, or (3) Mixed Meal. A fourth group was given saline as a control. Blood was collected via tail snip and analyzed for glucose, insulin, GLP-1, GIP, PYY, amylin, leptin, and ghrelin. Dextrose resulted in the highest blood glucose at T15 (P = 0.014), while the mixed meal was significantly higher than saline from T30-T120 (P < 0.05). Insulin was higher at T15 with dextrose compared to saline (P = 0.031) and Ensure® (P = 0.033). GLP-1 tAUC was significantly higher with dextrose compared to mixed meal (P = 0.04) while GIP tAUC was higher with dextrose and mixed meal compared to saline (P < 0.05). Changes in tAUC for insulin, amylin, leptin, ghrelin, and PYY did not reach significance. Based on these findings, dextrose appears to provide a robust acute glycemic and hormone response and is therefore likely an appropriate oral solution to reproducibly test the impact of various dietary, surgical, or pharmacological interventions on glucose and satiety hormone response.

Association of Metabolic Markers with self-reported osteoarthritis among middle-aged BMI-defined non-obese individuals: a cross-sectional study

BACKGROUND

Osteoarthritis (OA) is a chronic degenerative joint disease. While it is well-established that obesity affects OA through increased axial loading on the joint cartilage, the indirect effect of obesity through metabolic processes among the body mass index (BMI)-defined non-obese population, i.e., BMI < 30 kg/m2, is less known. Our goal was to evaluate the association of metabolic markers including body fat percentage (BF%), waist circumference, maximum weight gain during adulthood and serum creatinine with self-reported OA to establish if such measures offer additional information over BMI among the non-obese population between 40 and 65 years of age.

METHODS

Cross-sectional data from two cycles of the Canadian Health Measures Survey (CHMS) in 2007-2009 and 2009-2011 were analyzed. Sex-specific logistic regression models were developed to evaluate the association of self-reported OA with metabolic markers. Models were separately adjusted for age, BMI categories and serum creatinine, and a stratified analysis across BM categories was performed. In a secondary analysis, we evaluated the association of self-reported OA, cardiovascular diseases and hypertension across BF% categories.

RESULTS

Of 2462 individuals, 217 (8.8%) self-reported OA. After adjusting for age and BMI, those within BF%-defined overweight/obese category had 2.67 (95% CI: 1.32-3.51) and 2.11(95% CI: 1.38-3.21) times higher odds of reporting self-reported OA compared to those within BF%-defined athletic/acceptable category for females and males, respectively. BF% was also significantly associated with self-reported OA after adjusting for age and serum creatinine only among females (OR: 1.47, 95%CI: 1.12-1.84). Furthermore, among the BMI-defined overweight group, the age-adjusted odds of self-reported OA was significantly higher for overweight/obese BF% compared to athletic/acceptable BF% in both females and males. In a secondary analysis, we showed that the association of self-reported OA and hypertension/cardiovascular diseases is significantly higher among BF% overweight/obese (OR: 1.37, 95%CI: 1.19-3.09) compared to BF% athletic/acceptable (OR: 1.13, 95%CI: 0.87-2.82).

CONCLUSION

Our results provide corroborating evidence for a relationship between body fat and OA in a population-based study, while no significant independent correlates were found between other metabolic markers and OA prevalence. Future investigation on the longitudinal relationship between BF and OA among this sub-population may inform targeted prevention opportunities.

High-fat/high-sucrose diet-induced obesity results in joint-specific development of osteoarthritis-like degeneration in a rat model

Objectives

Metabolic syndrome and low-grade systemic inflammation are associated with knee osteoarthritis (OA), but the relationships between these factors and OA in other synovial joints are unclear. The aim of this study was to determine if a high-fat/high-sucrose (HFS) diet results in OA-like joint damage in the shoulders, knees, and hips of rats after induction of obesity, and to identify potential joint-specific risks for OA-like changes.

Methods

A total of 16 male Sprague-Dawley rats were allocated to either the diet-induced obesity group (DIO, 40% fat, 45% sucrose, n = 9) or a chow control diet (n = 7) for 12 weeks. At sacrifice, histological assessments of the shoulder, hip, and knee joints were performed. Serum inflammatory mediators and body composition were also evaluated. The total Mankin score for each animal was assessed by adding together the individual Modified Mankin scores across all three joints. Linear regression modelling was conducted to evaluate predictive relationships between serum mediators and total joint damage.

Results

The HFS diet, in the absence of trauma, resulted in increased joint damage in the shoulder and knee joints of rats. Hip joint damage, however, was not significantly affected by DIO, consistent with findings in human studies. The total Mankin score was increased in DIO animals compared with the chow group, and was associated with percentage of body fat. Positive significant predictive relationships for total Mankin score were found between body fat and two serum mediators (interleukin 1 alpha (IL-1α) and vascular endothelial growth factor (VEGF)).

Conclusion

Systemic inflammatory alterations from DIO in this model system may result in a higher risk for development of knee, shoulder, and multi-joint damage with a HFS diet.Cite this article: K. H. Collins, D. A. Hart, R. A. Seerattan, R. A. Reimer, W. Herzog. High-fat/high-sucrose diet-induced obesity results in joint-specific development of osteoarthritis-like degeneration in a rat model. Bone Joint Res 2018;7:274-281. DOI: 10.1302/2046-3758.74.BJR-2017-0201.R2.

Fitness Level and Not Aging per se, Determines the Oxygen Uptake Kinetics Response

Although aging has been associated to slower V˙O₂ kinetics, some evidence indicates that fitness status and not aging per se might modulate this response. The main goal of this study was to examine the V˙O₂, deoxygenated hemoglobin+myoglobin (deoxy-[Hb+Mb]) kinetics, and the NIRS-derived vascular reperfusion responses in older compared to young men of different training levels (i.e., inactive, recreationally active, and endurance trained). Ten young inactive [YI; 26 ± 5 yrs.; peak V˙O₂ (V˙O_2peak), 2.96 ± 0.55 L·min⁻¹], 10 young recreationally active (YR; 26 ± 6 yrs.; 3.92 ± 0.33 L·min⁻¹), 10 young endurance trained (YT; 30 ± 4 yrs.; 4.42 ± 0.32 L·min⁻¹), 7 older inactive (OI; 69 ± 4 yrs.; 2.50 ± 0.31 L·min⁻¹), 10 older recreationally active (OR; 69 ± 5 yrs.; 2.71 ± 0.42 L·min⁻¹), and 10 older endurance trained (OT; 66 ± 3 yrs.; 3.20 ± 0.35 L·min⁻¹) men completed transitions of moderate intensity cycling exercise (MODS) to determine V˙O₂ and deoxy-[Hb+Mb] kinetics, and the deoxy-[Hb+Mb]/V˙O₂ ratio. The time constant of V˙O₂ (τV˙O₂) was greater in YI (38.8 ± 10.4 s) and OI (44.1 ± 10.8 s) compared with YR (26.8 ± 7.5 s) and OR (26.6 ± 6.5 s), as well as compared to YT (14.8 ± 3.4 s), and OT (17.7 ± 2.7 s) (p < 0.05). τV˙O₂ was greater in YR and OR compared with YT and OT (p < 0.05). The deoxy-[Hb+Mb]/V˙O₂ ratio was greater in YI (1.23 ± 0.05) and OI (1.29 ± 0.08) compared with YR (1.11 ± 0.03) and OR (1.13 ± 0.06), as well as compared to YT (1.01 ± 0.03), and OT (1.06 ± 0.03) (p < 0.05). Similarly, the deoxy-[Hb+Mb]/ V˙O₂ ratio was greater in YR and OR compared with YT and OT (p < 0.05). There was a main effect of training (p = 0.033), whereby inactive (p = 0.018) and recreationally active men (p = 0.031) had significantly poorer vascular reperfusion than endurance trained men regardless of age. This study demonstrated not only that age-related slowing of V˙O₂ kinetics can be eliminated in endurance trained individuals, but also that inactive lifestyle negatively impacts the V˙O₂ kinetics response of young healthy individuals.

Prevalence of comorbid conditions pre-existing and diagnosed at a tertiary care pediatric weight management clinic

BACKGROUND

Childhood obesity places individuals at risk for a multitude of physical and mental health problems. The aim of this study was to assess the prevalence of obesity related comorbidities diagnosed prior to and after attending a tertiary care pediatric weight management clinic.

METHODS

A cross sectional retrospective chart review of patients 2-17 years old seen in the weight management clinic at Alberta Children's Hospital from May 2012 to May 2014.

RESULTS

A total of 199 patients were included in the review. Comorbidity prevalences were: hypertension 6 (3%), prediabetes 11 (5.5%), type 2 diabetes 3 (1.5%), dyslipidemia 105 (52.8%), non-alcoholic fatty liver disease 31 (15.6%), asthma 45 (22.6%), obstructive sleep apnea 21 (10.6%), and polycystic ovarian syndrome (PCOS) 9 (12% of females ≥10 years at the first visit). Concerns related to depression and anxiety were present in 20 (10.1%) and 25 (12.6%) patients respectively. The majority of comorbidities were identified prior to joining the clinic. Conditions requiring more specialized tests, such as diabetes and PCOS, were more commonly identified after joining the clinic.

CONCLUSIONS

These results give further insight into the prevalence of obesity-related comorbidities in overweight and obese children and adolescents, and demonstrate the importance of screening for these known comorbidities. It is important to have the resources and an experienced multi-disciplinary team to follow children and their families through treatment.

Acute and chronic changes in rat soleus muscle after high-fat high-sucrose diet

The effects of obesity on different musculoskeletal tissues are not well understood. The glycolytic quadriceps muscles are compromised with obesity, but due to its high oxidative capacity, the soleus muscle may be protected against obesity‐induced muscle damage. To determine the time–course relationship between a high‐fat/high‐sucrose (HFS) metabolic challenge and soleus muscle integrity, defined as intramuscular fat invasion, fibrosis and molecular alterations over six time points. Male Sprague‐Dawley rats were fed a HFS diet (n = 64) and killed at serial short‐term (3 days, 1 week, 2 weeks, 4 weeks) and long‐term (12 weeks, 28 weeks) time points. Chow‐fed controls (n = 21) were killed at 4, 12, and 28 weeks. At sacrifice, animals were weighed, body composition was calculated (DXA), and soleus muscles were harvested and flash‐frozen. Cytokine and adipokine mRNA levels for soleus muscles were assessed, using RT‐qPCR. Histological assessment of muscle fibrosis and intramuscular fat was conducted, CD68⁺ cell number was determined using immunohistochemistry, and fiber typing was assessed using myosin heavy chain protein analysis. HFS animals demonstrated significant increases in body fat by 1 week, and this increase in body fat was sustained through 28 weeks on the HFS diet. Short‐term time‐point soleus muscles demonstrated up‐regulated mRNA levels for inflammation, atrophy, and oxidative stress molecules. However, intramuscular fat, fibrosis, and CD68⁺ cell number were similar to their respective control group at all time points evaluated. Therefore, the oxidative capacity of the soleus may be protective against diet‐induced alterations to muscle integrity. Increasing oxidative capacity of muscles using aerobic exercise may be a beneficial strategy for mitigating obesity‐induced muscle damage, and its consequences.

Immune response in highly active young men to the 2014/2015 seasonal influenza vaccine

During the 2009 H1N1 pandemic, individuals with obesity were disproportionately affected by H1N1 with increased levels of mortality and morbidity. This led to questions regarding the potential impact of lifestyle on the effectiveness of immunization. Currently, the research is limited on influenza vaccination and the associated changes in immune response with body composition and physical activity. The purpose of this pilot study was to investigate the potential role of adiposity and physical activity in the immune response elicited by the 2014/2015 seasonal trivalent influenza vaccine. A prospective cohort study examining the 2014/2015 seasonal trivalent influenza vaccine was conducted by collecting baseline and 4-week postvaccination fasting blood samples from 45 male Albertans between the ages of 18 and 35 years. Percent body fat (%BF) was assessed through dual X-ray absorptiometry imagining and physical activity through self-reported survey scores. While no differences in median %BF were associated with seroconversion rates in participants, the median physical activity score was higher among those that did not seroconvert to the vaccine. Significant differences were found for the A/Texas strain (p < 0.01) and a similar trend of lower magnitude observed for the remaining 2 influenza strains. These results suggest that higher physical activity levels may influence immune response to vaccination and that assessing factors beyond those commonly used can be of value when identifying vaccine response in the population.

Obesity, Metabolic Syndrome, and Musculoskeletal Disease: Common Inflammatory Pathways Suggest a Central Role for Loss of Muscle Integrity

Inflammation can arise in response to a variety of stimuli, including infectious agents, tissue injury, autoimmune diseases, and obesity. Some of these responses are acute and resolve, while others become chronic and exert a sustained impact on the host, systemically, or locally. Obesity is now recognized as a chronic low-grade, systemic inflammatory state that predisposes to other chronic conditions including metabolic syndrome (MetS). Although obesity has received considerable attention regarding its pathophysiological link to chronic cardiovascular conditions and type 2 diabetes, the musculoskeletal (MSK) complications (i.e., muscle, bone, tendon, and joints) that result from obesity-associated metabolic disturbances are less frequently interrogated. As musculoskeletal diseases can lead to the worsening of MetS, this underscores the imminent need to understand the cause and effect relations between the two, and the convergence between inflammatory pathways that contribute to MSK damage. Muscle mass is a key predictor of longevity in older adults, and obesity-induced sarcopenia is a significant risk factor for adverse health outcomes. Muscle is highly plastic, undergoes regular remodeling, and is responsible for the majority of total body glucose utilization, which when impaired leads to insulin resistance. Furthermore, impaired muscle integrity, defined as persistent muscle loss, intramuscular lipid accumulation, or connective tissue deposition, is a hallmark of metabolic dysfunction. In fact, many common inflammatory pathways have been implicated in the pathogenesis of the interrelated tissues of the musculoskeletal system (e.g., tendinopathy, osteoporosis, and osteoarthritis). Despite these similarities, these diseases are rarely evaluated in a comprehensive manner. The aim of this review is to summarize the common pathways that lead to musculoskeletal damage and disease that result from and contribute to MetS. We propose the overarching hypothesis that there is a central role for muscle damage with chronic exposure to an obesity-inducing diet. The inflammatory consequence of diet and muscle dysregulation can result in dysregulated tissue repair and an imbalance toward negative adaptation, resulting in regulatory failure and other musculoskeletal tissue damage. The commonalities support the conclusion that musculoskeletal pathology with MetS should be evaluated in a comprehensive and integrated manner to understand risk for other MSK-related conditions. Implications for conservative management strategies to regulate MetS are discussed, as are future research opportunities.

Neutralization of IL-15 abrogates experimental immune-mediated cholangitis in diet-induced obese mice

Obesity is a global epidemic affecting chronic inflammatory diseases. Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease that can occur as an extraintestinal manifestation of inflammatory bowel disease (IBD). Previously we reported that patients with PSC who are obese have a higher risk of advanced liver disease. Currently it is unknown how obesity accelerates or worsens PSC. We evaluated the progression of PSC in an antigen-driven cholangitis mouse model of diet-induced obesity. Obesity was induced in our murine model of immune-mediated cholangitis (OVAbil). OVAbil mice were fed standard chow or high-fat/sucrose diet for twelve weeks followed by induction of biliary inflammation by OVA-specific T cell transfer. Histopathological damage in portal tracts was scored and serum collected. Neutralizing antibodies against IL-15 were administered daily until study termination. Obese mice developed exacerbated liver inflammation and damage. Immune cell phenotyping in liver revealed greater numbers of neutrophils and CD8+ T cells in obese mice. Higher levels of cytokines and chemokines were found in obese mice with cholangitis. Immuno-neutralizing antibodies against IL-15 greatly attenuated cholangitis in obese mice. Obesity exacerbated experimental PSC in part by overproduction of IL-15. Timely targeting of IL-15 may slow the progression of PSC.

Potential Impact of Metabolic and Gut Microbial Response to Pregnancy and Lactation in Lean and Diet-Induced Obese Rats on Offspring Obesity Risk

SCOPE

Maternal obesity programs metabolic dysfunction in offspring, increasing their susceptibility to obesity and metabolic diseases in later life. Moreover, pregnancy and lactation are associated with many metabolic adaptations, yet it is unclear how diet-induced maternal obesity may interrupt these processes.

METHODS AND RESULTS

¹ H NMR serum metabolomics analysis was performed on samples collected pre-pregnancy and in pregnant and lactating lean and high fat/sucrose (HFS) diet-induced obese Sprague-Dawley rats to identify maternal metabolic pathways associated with developmental programming of offspring obesity. Gut microbial composition was assessed using qPCR. Offspring of HFS dams had nearly 40% higher adiposity at weaning compared to offspring of lean dams. While pregnancy and lactation were associated with distinct maternal metabolic changes common to both lean and obese dams, we identified several metabolic differences, potentially implicating dysregulated one-carbon and mammary gland metabolism in the metabolic programming of obesity. Gut microbial composition was significantly altered with obesity, and both gestation and lactation were accompanied by changes in gut microbiota.

CONCLUSION

Diet-induced maternal obesity and consumption of an obesogenic maternal diet results in differential metabolic and gut microbial adaptations to pregnancy and lactation; these maladaptations may be directly involved in maternal programming of offspring susceptibility to obesity.

Near-infrared spectroscopy can detect differences in vascular responsiveness to a hyperglycaemic challenge in individuals with obesity compared to normal-weight individuals

OBJECTIVE

To examine whether the near-infrared spectroscopy combined with vascular occlusion test technique could detect differences in vascular responsiveness during hyperglycaemia between normal-weight individuals and individuals with obesity.

METHODS

A total of 16 normal-weight individuals (body mass index, 21.3 ± 1.7 kg/m²) and 13 individuals with obesity (body mass index, 34.4 ± 2.0 kg/m²) were submitted to five vascular occlusion tests (Pre, 30, 60, 90 and 120 min after glucose challenge). Vascular responsiveness was determined by the Slope 2 (Slope 2 StO₂) and the area under the curve (StO_2AUC) of oxygen saturation derived from near-infrared spectroscopy-vascular occlusion test.

RESULTS

The Slope 2 StO₂ increased from 1.07 ± 0.16%/s (Pre) to 1.53 ± 0.21%/s at 90 min ( p < 0.05) in the control group, while in obese it increased from 0.71 ± 0.09%/s (Pre) to 0.92 ± 0.14%/s at 60 min ( p < 0.05), and to 0.97 ± 0.10%/s ( p < 0.01) at 120 min after glucose ingestion. The StO_2AUC decreased from 1729 ± 214% . sec (Pre) to 1259 ± 232% . sec at 60 min ( p < 0.05) and to 1034 ± 172% . sec at 90 min ( p < 0.05) in the normal-weight group, whereas it decreased at 90 min (637 ± 98% . sec; p < 0.05) and at 120 min (590 ± 93% . sec; p < 0.01) compared to 30 min (1232 ± 197% . sec) after glucose ingestion in individuals with obesity.

CONCLUSION

Near-infrared spectroscopy-vascular occlusion test technique was capable of detecting differences in vascular responsiveness during hyperglycaemia between normal-weight individuals and individuals with obesity.

Metabolic inflexibility in individuals with obesity assessed by near-infrared spectroscopy

OBJECTIVE

To non-invasively evaluate differences in oxidative metabolism in individuals with obesity compared to normal weight using the near-infrared spectroscopy and vascular occlusion technique during hyperglycaemia.

METHODS

In all, 16 normal-weight individuals (body mass index: 21.3 ± 1.7 kg/m²) and 13 individuals with obesity (body mass index: 34.4 ± 2.0 kg/m²) had five vascular occlusion tests (pre, 30, 60, 90 and 120 min after glucose ingestion). Oxygen utilization was estimated from the area under the curve of the deoxyhemoglobin [HHb] signal during occlusion. Muscle reperfusion was derived from the area above the curve after cuff release.

RESULTS

The deoxyhemoglobin area under the curve during occlusion of the normal-weight individuals increased from 15,732 ± 2344 (% . s) at pre to 18,930 ± 3226 (% . s) ( p < 0.05) at 90 min after glucose ingestion. The deoxyhemoglobin area under the curve during occlusion decreased significantly from 14,695 ± 3341 (% . s) at pre to 11,273 ± 1825 (% . s) ( p < 0.05) and 11,360 ± 1750 (% . s) ( p < 0.05) at 30 and 60 min, respectively, after glucose ingestion. The area above the curve of deoxyhemoglobin during reperfusion decreased significantly from 6450 ± 765 (% . s) at pre to 4830 ± 963 (% . s) ( p < 0.05) at 60 min and to 4210 ± 595 (% . s) ( p < 0.01) at 90 min in normal-weight individuals after glucose ingestion, with no changes observed in individuals with obesity.

CONCLUSION

This study confirmed in vivo and non-invasively the metabolic inflexibility of skeletal muscle in individuals with obesity during hyperglycaemia.

Dairy Attenuates Weight Gain to a Similar Extent as Exercise in Rats Fed a High-Fat, High-Sugar Diet

OBJECTIVE

To compare the individual and combined effects of dairy and endurance exercise training in reducing weight gain and adiposity in a rodent model of diet-induced obesity.

METHODS

An 8-week feeding intervention of a high-fat, high-sugar diet was used to induce obesity in male Sprague-Dawley rats. Rats were then assigned to one of four groups for 6 weeks: (1) casein sedentary (casein-S), (2) casein exercise (casein-E), (3) dairy sedentary (dairy-S), and (4) dairy exercise (dairy-E). Rats were exercise trained by treadmill running 5 d/wk.

RESULTS

Dairy-E prevented weight gain to a greater extent than either dairy or exercise alone. Adipose tissue and liver mass were reduced to a similar extent in dairy-S, casein-E, and dairy-E groups. Differences in weight gain were not explained by food intake or total energy expenditure. The total amount of lipid excreted was greater in the dairy-S compared to casein-S and dairy-E groups.

CONCLUSIONS

This study provides evidence that dairy limits weight gain to a similar extent as exercise training and the combined effects are greater than either intervention alone. While exercise training reduces weight gain through increases in energy expenditure, dairy appears to increase lipid excretion in the feces.