Plasma Proteomic Kinetics in Response to Acute Exercise.

Regular exercise has many favorable effects on human health, which may be mediated in part by the release of circulating bioactive factors during each bout of exercise. Limited data exist regarding the kinetic responses of plasma proteins during and after acute exercise. Proteomic profiling of 4163 proteins was performed using a large-scale, affinity-based platform in 75 middle-aged adults who were referred for treadmill exercise stress testing. Plasma proteins were quantified at baseline, peak exercise, and 1-h postexercise, and those with significant changes at both exercise timepoints were further examined for their associations with cardiometabolic traits and change with aerobic exercise training in the Health, Risk Factors, Exercise Training and Genetics Family Study, a 20-week exercise intervention study. A total of 765 proteins changed (false discovery rate < 0.05) at peak exercise compared to baseline, and 128 proteins changed (false discovery rate < 0.05) at 1-h postexercise. The 56 proteins that changed at both timepoints included midkine, brain-derived neurotrophic factor, metalloproteinase inhibitor 4, and coiled-coil domain-containing protein 126 and were enriched for secreted proteins. The majority had concordant direction of change at both timepoints. Across all proteins assayed, gene set enrichment analysis showed increased abundance of coagulation-related proteins at 1-h postexercise. Forty-five proteins were associated with at least one measure of adiposity, lipids, glucose homeostasis, or cardiorespiratory fitness in Health, Risk Factors, Exercise Training and Genetics Family Study, and 20 proteins changed with aerobic exercise training. We identified hundreds of novel proteins that change during acute exercise, most of which resolved by 1 h into recovery. Proteins with sustained changes during exercise and recovery may be of particular interest as circulating biomarkers and pathways for further investigation in cardiometabolic diseases. These data will contribute to a biochemical roadmap of acute exercise that will be publicly available for the entire scientific community.

Effects of exercise training on ANGPTL3/8 and ANGPTL4/8 and their associations with cardiometabolic traits.

Angiopoietin-like protein (ANGPTL) complexes 3/8 and 4/8 are established inhibitors of LPL and novel therapeutic targets for dyslipidemia. However, the effects of regular exercise on ANGPTL3/8 and ANGPTL4/8 are unknown. We characterized ANGPTL3/8 and ANGPTL4/8 and their relationship with in vivo measurements of lipase activities and cardiometabolic traits before and after a 5-month endurance exercise training intervention in 642 adults from the HERITAGE (HEalth, RIsk factors, exercise Training And GEnetics) Family Study. At baseline, higher levels of both ANGPTL3/8 and ANGPTL4/8 were associated with a worse lipid, lipoprotein, and cardiometabolic profile, with only ANGPTL3/8 associated with postheparin LPL and HL activities. ANGPTL3/8 significantly decreased with exercise training, which corresponded with increases in LPL activity and decreases in HL activity, plasma triglycerides, apoB, visceral fat, and fasting insulin (all P < 5.1 × 10-4). Exercise-induced changes in ANGPTL4/8 were directly correlated to concomitant changes in total cholesterol, LDL-C, apoB, and HDL-triglycerides and inversely related to change in insulin sensitivity index (all P < 7.0 × 10-4). In conclusion, exercise-induced decreases in ANGPTL3/8 and ANGPTL4/8 were related to concomitant improvements in lipase activity, lipid profile, and cardiometabolic risk factors. These findings reveal the ANGPTL3-4-8 model as a potential molecular mechanism contributing to adaptations in lipid metabolism in response to exercise training.

Inverse association between apolipoprotein C-II and cardiovascular mortality: role of lipoprotein lipase activity modulation.

AIMS: Apolipoprotein C-II (ApoC-II) is thought to activate lipoprotein lipase (LPL) and is therefore a possible target for treating hypertriglyceridemia. Its relationship with cardiovascular risk has not been investigated in large-scale epidemiologic studies, particularly allowing for apolipoprotein C-III (ApoC-III), an LPL antagonist. Furthermore, the exact mechanism of ApoC-II-mediated LPL activation is unclear. METHODS AND RESULTS: ApoC-II was measured in 3141 LURIC participants of which 590 died from cardiovascular diseases during a median (inter-quartile range) follow-up of 9.9 (8.7-10.7) years. Apolipoprotein C-II-mediated activation of the glycosylphosphatidylinositol high-density lipoprotein binding protein 1 (GPIHBP1)-LPL complex was studied using enzymatic activity assays with fluorometric lipase and very low-density lipoprotein (VLDL) substrates. The mean ApoC-II concentration was 4.5 (2.4) mg/dL. The relationship of ApoC-II quintiles with cardiovascular mortality exhibited a trend toward an inverse J-shape, with the highest risk in the first (lowest) quintile and lowest risk in the middle quintile. Compared with the first quintile, all other quintiles were associated with decreased cardiovascular mortality after multivariate adjustments including ApoC-III as a covariate (all P < 0.05). In experiments using fluorometric substrate-based lipase assays, there was a bell-shaped relationship for the effect of ApoC-II on GPIHBP1-LPL activity when exogenous ApoC-II was added. In ApoC-II-containing VLDL substrate-based lipase assays, GPIHBP1-LPL enzymatic activity was almost completely blocked by a neutralizing anti-ApoC-II antibody. CONCLUSION: The present epidemiologic data suggest that increasing low circulating ApoC-II levels may reduce cardiovascular risk. This conclusion is supported by the observation that optimal ApoC-II concentrations are required for maximal GPIHBP1-LPL enzymatic activity.

Omics-driven investigation of the biology underlying intrinsic submaximal working capacity and its trainability.

Submaximal exercise capacity is an indicator of cardiorespiratory fitness with clinical and public health implications. Submaximal exercise capacity and its response to exercise programs are characterized by heritability levels of about 40%. Using physical working capacity (power output) at a heart rate of 150 beats/min (PWC150) as an indicator of submaximal exercise capacity in subjects of the HERITAGE Family Study, we have undertaken multi-omics and in silico explorations of the underlying biology of PWC150 and its response to 20 wk of endurance training. Our goal was to illuminate the biological processes and identify panels of genes associated with human variability in intrinsic PWC150 (iPWC150) and its trainability (dPWC150). Our bioinformatics approach was based on a combination of genome-wide association, skeletal muscle gene expression, and plasma proteomics and metabolomics experiments. Genes, proteins, and metabolites showing significant associations with iPWC150 or dPWC150 were further queried for the enrichment of biological pathways. We compared genotype-phenotype associations of emerging candidate genes with reported functional consequences of gene knockouts in mouse models. We investigated the associations between DNA variants and multiple muscle and cardiovascular phenotypes measured in HERITAGE subjects. Two panels of prioritized genes of biological relevance to iPWC150 (13 genes) and dPWC150 (6 genes) were identified, supporting the hypothesis that genes and pathways associated with iPWC150 are different from those underlying dPWC150. Finally, the functions of these genes and pathways suggested that human variation in submaximal exercise capacity is mainly driven by skeletal muscle morphology and metabolism and red blood cell oxygen-carrying capacity.NEW & NOTEWORTHY Multi-omics and in silico explorations of the genes and underlying biology of submaximal exercise capacity and its response to 20 wk of endurance training were undertaken. Prioritized genes were identified: 13 genes for variation in submaximal exercise capacity in the sedentary state and 5 genes for the response level to endurance training, with no overlap between them. Genes and pathways associated with submaximal exercise capacity in the sedentary state are different from those underlying trainability.

Whole Genome Sequence Analysis of the Plasma Proteome in Black Adults Provides Novel Insights Into Cardiovascular Disease.

BACKGROUND: Plasma proteins are critical mediators of cardiovascular processes and are the targets of many drugs. Previous efforts to characterize the genetic architecture of the plasma proteome have been limited by a focus on individuals of European descent and leveraged genotyping arrays and imputation. Here we describe whole genome sequence analysis of the plasma proteome in individuals with greater African ancestry, increasing our power to identify novel genetic determinants. METHODS: Proteomic profiling of 1301 proteins was performed in 1852 Black adults from the Jackson Heart Study using aptamer-based proteomics (SomaScan). Whole genome sequencing association analysis was ascertained for all variants with minor allele count ≥5. Results were validated using an alternative, antibody-based, proteomic platform (Olink) as well as replicated in the Multi-Ethnic Study of Atherosclerosis and the HERITAGE Family Study (Health, Risk Factors, Exercise Training and Genetics). RESULTS: We identify 569 genetic associations between 479 proteins and 438 unique genetic regions at a Bonferroni-adjusted significance level of 3.8×10-11. These associations include 114 novel locus-protein relationships and an additional 217 novel sentinel variant-protein relationships. Novel cardiovascular findings include new protein associations at the APOE gene locus including ZAP70 (sentinel single nucleotide polymorphism [SNP] rs7412-T, ß=0.61±0.05, P=3.27×10-30) and MMP-3 (ß=-0.60±0.05, P=1.67×10-32), as well as a completely novel pleiotropic locus at the HPX gene, associated with 9 proteins. Further, the associations suggest new mechanisms of genetically mediated cardiovascular disease linked to African ancestry; we identify a novel association between variants linked to APOL1-associated chronic kidney and heart disease and the protein CKAP2 (rs73885319-G, ß=0.34±0.04, P=1.34×10-17) as well as an association between ATTR amyloidosis and RBP4 levels in community-dwelling individuals without heart failure. CONCLUSIONS: Taken together, these results provide evidence for the functional importance of variants in non-European populations, and suggest new biological mechanisms for ancestry-specific determinants of lipids, coagulation, and myocardial function.

A 12-Week Randomized Intervention Comparing the Healthy US, Mediterranean, and Vegetarian Dietary Patterns of the US Dietary Guidelines for Changes in Body Weight, Hemoglobin A1c, Blood Pressure, and Dietary Quality among African American Adults.

BACKGROUND: The US Dietary Guidelines (USDG) form the basis of nutrition guidelines, but the research informing the 3 USDG dietary patterns (Healthy US-Style [H-US], Mediterranean [Med], and vegetarian [Veg]) has been drawn largely from observational studies among White populations. OBJECTIVES: The Dietary Guidelines 3 Diets study was a 3-arm, 12-wk randomly assigned intervention among African American (AA) adults at risk of type 2 diabetes mellitus that tested the 3 USDG dietary patterns. METHODS: The AAs (ages 18-65 y, BMI 25-49.9 kg/m2, and BMI was measured in kg/m2) with ≥3 type 2 diabetes mellitus risk factors were recruited. Weight, HbA1c, blood pressure, and dietary quality (healthy eating index [HEI]) were collected at baseline and 12 wk. In addition, participants attended weekly online classes that were designed using material from the USDG/MyPlate. Repeated measures, mixed models with maximum likelihood estimation, and robust computation of standard errors were tested. RESULTS: Of the 227 participants screened, 63 were eligible (83% female; age 48.0 ± 10.6 y, BMI 35.9 ± 0.8 kg/m2) and randomly assigned to the Healthy US-Style Eating Pattern (H-US) (n = 21, 81% completion), healthy Mediterranean-style eating pattern (Med) (n = 22, 86% completion), or healthy vegetarian eating pattern (Veg) (n = 20, 70% completion) groups. Within-group, but not between groups, weight loss was significant (-2.4 ± 0.7 kg H-US, -2.6 ± 0.7 kg Med, -2.4 ± 0.8 kg Veg; P = 0.97 between group). There was also no significant difference between groups for changes in HbA1c (0.03 ± 0.05% H-US, -0.10 ± 0.05% Med, 0.07 ± 0.06% Veg; P = 0.10), systolic BP (-5.5 ± 2.7 mmHg H-US, -3.2 ± 2.5 mmHg Med, -2.4 ± 2.9 mmHg Veg; P = 0.70), diastolic blood pressure (-5.2 ± 1.8 mmHg H-US, -2.0 ± 1.7 mmHg Med, -3.4 ± 1.9 mmHg Veg; P = 0.41), or HEI (7.1 ± 3.2 H-US, 15.2 ± 3.1 Med, 4.6 ± 3.4 Veg; P = 0.06). Post hoc analyses showed that the Med group had significantly greater improvements in HEI compared to the Veg group (difference = -10.6 ± 4.6; 95% CI: -19.7, -1.4; P = 0.02). CONCLUSIONS: The present study demonstrates that all 3 USDG dietary patterns lead to significant weight loss among AA adults. However, none of the outcomes were significantly different between groups. This trial was registered at clinicaltrials.gov as NCT04981847.

Regular exercise and patterns of response across multiple cardiometabolic traits: the HERITAGE family study.

OBJECTIVES: We investigated whether high responsiveness or low responsiveness to exercise training aggregates in the same individuals across seven cardiometabolic traits. METHODS: A total of 564 adults (29.2% black, 53.7% female) from the HERITAGE family study completed a 20-week endurance training programme (at 55%-75% of participants' maximal oxygen uptake (VO2max)) with VO2max, per cent body fat, visceral adipose tissue, fasting levels of insulin, high-density lipoprotein cholesterol, small low-density lipoprotein particles and inflammatory marker GlycA measured before and after training. For each exercise response trait, we created ethnicity-specific, sex-specific and generation-specific quintiles. High responses were defined as those within the 20th percentile representing the favourable end of the response trait distribution, low responses were defined as the 20th percentile from the least favourable end, and the remaining were labelled as average responses. RESULTS: Only one individual had universally high or low responses for all seven cardiometabolic traits. Almost half (49%) of the cohort had at least one high response and one low response across the seven traits. About 24% had at least one high response but no low responses, 24% had one or more low responses but no high responses, and 2.5% had average responses across all traits. CONCLUSIONS: Interindividual variation in exercise responses was evident in all the traits we investigated, and responsiveness did not aggregate consistently in the same individuals. While adherence to an exercise prescription is known to produce health benefits, targeted risk factors may not improve.

Effects of exercise on HDL functionality.

PURPOSE OF REVIEW: Low HDL-cholesterol (HDL-C) levels are a strong predictor of cardiovascular disease risk and can be improved with regular exercise. However, raising HDL-C levels pharmacologically has not shown convincing clinical benefits. Thus, research has recently focused on identifying therapies that improve HDL function, with exercise representing such a potential therapy. The purpose of this review is to summarize the effects of exercise interventions on HDL function. RECENT FINDINGS: The effects of exercise and lifestyle interventions on the primary atheroprotective functions of HDL are reviewed, namely, cholesterol efflux, antioxidative, and anti-inflammatory properties. Differences in study design, study population, and assays are discussed to aid in the interpretation of the reviewed studies. SUMMARY: There is mixed evidence that regular aerobic exercise improves cholesterol efflux capacity, with recent research suggesting an exercise dose threshold needs to be exceeded to produce beneficial effects. There is preliminary evidence that exercise improves the antioxidative and anti-inflammatory properties of HDL. Although exercise represents a potential therapeutic approach to improve HDL function, the heterogeneity and/or lack of findings warrants more and larger studies to determine what HDL function(s) are most responsive to regular exercise and what dose of exercise elicits the greatest improvements in HDL functionality.

Disparities in childhood overweight and obesity by income in the United States: an epidemiological examination using three nationally representative datasets.

BACKGROUND/OBJECTIVES: Overweight and obesity (OWOB) is a global epidemic. Adults and adolescents from low-income households are at higher risk to be OWOB. This study examined the relationship between income and OWOB prevalence in children and adolescents (518 years) in the United States (US) within and across race/ethnicities, and changes in this relationship from 1971 to 2014. SUBJECTS/METHODS: A meta-analysis of a nationally representative sample (N = 73,891) of US children and adolescents drawn from three datasets (i.e., National Health and Nutrition Examination Survey, National Longitudinal Survey of Youth, & the Early Childhood Longitudinal Program) which included 14 cross-sectional waves spanning 1971-2014 was conducted. The exposure was household income-to-poverty ratio (low income = 0.00-1.00, middle income = 1.01-4.00, high income >4.00) with prevalence of overweight or obesity (body mass index ≥ 85th percentile) as the outcome. RESULTS: Children and adolescents from middle-income and high-income households were 0.78 (95% CI = 0.72, 0.83) and 0.68 (95% CI = 0.59, 0.77) times as likely to be OWOB compared to children and adolescents in low-income households. Separate analyses restricted to each racial/ethnic group showed children and adolescents from middle- and high-income households were less likely to be OWOB compared to their low-income peers within the White, Hispanic, and Other race/ethnic groups. Children and adolescents from low-income households who were Black were not more likely to be OWOB than their high- and middle-income counterparts. Analyses within each income stratum indicated that race/ethnicity was not related to the prevalence of OWOB in low-income households. However, racial/ethnic differences in OWOB were evident for children and adolescents in middle- and high-income households. Disparities in the prevalence of OWOB between low-income children and adolescents and their middle- and high-income counterparts have increased from 1971 to 2014. CONCLUSIONS: Income and OWOB are related in US children and adolescents. Racial/ethnic differences in the prevalence of OWOB emerge in middle- and high-income households. Disparities in OWOB prevalence are growing.

Effects of Increasing Exercise Intensity and Dose on Multiple Measures of HDL (High-Density Lipoprotein) Function.

OBJECTIVE: Measures of HDL (high-density lipoprotein) function are associated with cardiovascular disease. However, the effects of regular exercise on these measures is largely unknown. Thus, we examined the effects of different doses of exercise on 3 measures of HDL function in 2 randomized clinical exercise trials. APPROACH AND RESULTS: Radiolabeled and boron dipyrromethene difluoride-labeled cholesterol efflux capacity and HDL-apoA-I (apolipoprotein A-I) exchange were assessed before and after 6 months of exercise training in 2 cohorts: STRRIDE-PD (Studies of Targeted Risk Reduction Interventions through Defined Exercise, in individuals with Pre-Diabetes; n=106) and E-MECHANIC (Examination of Mechanisms of exercise-induced weight compensation; n=90). STRRIDE-PD participants completed 1 of 4 exercise interventions differing in amount and intensity. E-MECHANIC participants were randomized into 1 of 2 exercise groups (8 or 20 kcal/kg per week) or a control group. HDL-C significantly increased in the high-amount/vigorous-intensity group (3±5 mg/dL; P=0.02) of STRRIDE-PD, whereas no changes in HDL-C were observed in E-MECHANIC. In STRRIDE-PD, global radiolabeled efflux capacity significantly increased 6.2% (SEM, 0.06) in the high-amount/vigorous-intensity group compared with all other STRRIDE-PD groups (range, -2.4 to -8.4%; SEM, 0.06). In E-MECHANIC, non-ABCA1 (ATP-binding cassette transporter A1) radiolabeled efflux significantly increased 5.7% (95% CI, 1.2-10.2%) in the 20 kcal/kg per week group compared with the control group, with no change in the 8 kcal/kg per week group (2.6%; 95% CI, -1.4 to 6.7%). This association was attenuated when adjusting for change in HDL-C. Exercise training did not affect BODIPY-labeled cholesterol efflux capacity or HDL-apoA-I exchange in either study. CONCLUSIONS: Regular prolonged vigorous exercise improves some but not all measures of HDL function. Future studies are warranted to investigate whether the effects of exercise on cardiovascular disease are mediated in part by improving HDL function. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT00962962 and NCT01264406.

Precision exercise medicine: understanding exercise response variability.

There is evidence from human twin and family studies as well as mouse and rat selection experiments that there are considerable interindividual differences in the response of cardiorespiratory fitness (CRF) and other cardiometabolic traits to a given exercise programme dose. We developed this consensus statement on exercise response variability following a symposium dedicated to this topic. There is strong evidence from both animal and human studies that exercise training doses lead to variable responses. A genetic component contributes to exercise training response variability.In this consensus statement, we (1) briefly review the literature on exercise response variability and the various sources of variations in CRF response to an exercise programme, (2) introduce the key research designs and corresponding statistical models with an emphasis on randomised controlled designs with or without multiple pretests and post-tests, crossover designs and repeated measures designs, (3) discuss advantages and disadvantages of multiple methods of categorising exercise response levels-a topic that is of particular interest for personalised exercise medicine and (4) outline approaches that may identify determinants and modifiers of CRF exercise response. We also summarise gaps in knowledge and recommend future research to better understand exercise response variability.

Which US States Pose the Greatest Threats to Military Readiness and Public Health? Public Health Policy Implications for a Cross-sectional Investigation of Cardiorespiratory Fitness, Body Mass Index, and Injuries Among US Army Recruits.

OBJECTIVE: Many states in the southern region of the United States are recognized for higher rates of obesity, physical inactivity, and chronic disease. These states are therefore recognized for their disproportionate public health burden. The purpose of this study was to investigate state-level distributions of cardiorespiratory fitness, body mass index (BMI), and injuries among US Army recruits in order to determine whether or not certain states may also pose disproportionate threats to military readiness and national security. METHODS: Sex-specific state-level values for injuries and fitness among 165 584 Army recruits were determined. Next, the relationship between median cardiorespiratory fitness and injury incidence at the state level was examined using Spearman correlations. Finally, multivariable Poisson regression models stratified by sex examined state-level associations between fitness and injury incidence, while controlling for BMI, and other covariates. MAIN OUTCOME MEASURES: Cardiorespiratory fitness and training-related injury incidence. RESULTS: A cluster of 10 states from the south and southeastern regions (Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Texas) produced male or female recruits who were significantly less fit and/or more likely to become injured than recruits from other US states. Compared with the "most fit states," the incidence of injuries increased by 22% (95% CI, 17-28; P < .001) and 28% (95% CI, 19-36; P < .001) in male and female recruits from the "least fit states," respectively. CONCLUSIONS: The impact of policies, systems, and environments on physical activity behavior, and subsequently fitness and health, has been clearly established. Advocacy efforts aimed at active living policies, systems, and environmental changes to improve population health often fail. However, advocating for active living policies to improve national security may prove more promising, particularly with legislators. Results from this study demonstrate how certain states, previously identified for their disproportionate public health burden, are also disproportionately burdensome for military readiness and national security.

Proteomic characterization of high-density lipoprotein particles in patients with non-alcoholic fatty liver disease.

BACKGROUND: Metabolic diseases such as obesity and diabetes are associated with changes in high-density lipoprotein (HDL) particles, including changes in particle size and protein composition, often resulting in abnormal function. Recent studies suggested that patients with non-alcoholic fatty liver disease (NAFLD), including individuals with non-alcoholic steatohepatitis (NASH), have smaller HDL particles when compared to individuals without liver pathologies. However, no studies have investigated potential changes in HDL particle protein composition in patients with NAFLD, in addition to changes related to obesity, to explore putative functional changes of HDL which may increase the risk of cardiovascular complications. METHODS: From a cohort of morbidly obese females who were diagnosed with simple steatosis (SS), NASH, or normal liver histology, we selected five matched individuals from each condition for a preliminary pilot HDL proteome analysis. HDL particles were enriched using size-exclusion chromatography, and the proteome of the resulting fraction was analyzed by liquid chromatography tandem mass spectrometry. Differences in the proteomes between the three conditions (normal, SS, NASH) were assessed using label-free quantitative analysis. Gene ontology term analysis was performed to assess the potential impact of proteomic changes on specific functions of HDL particles. RESULTS: Of the 95 proteins identified, 12 proteins showed nominally significant differences between the three conditions. Gene ontology term analysis revealed that severity of the liver pathology may significantly impact the anti-thrombotic functions of HDL particles, as suggested by changes in the abundance of HDL-associated proteins such as antithrombin III and plasminogen. CONCLUSIONS: The pilot data from this study suggest that changes in the HDL proteome may impact the functionality of HDL particles in NAFLD and NASH patients. These proteome changes may alter cardio-protective properties of HDL, potentially contributing to the increased cardiovascular disease risk in affected individuals. Further validation of these protein changes by orthogonal approaches is key to confirming the role of alterations in the HDL proteome in NAFLD and NASH. This will help elucidate the mechanistic effects of the altered HDL proteome on cardioprotective properties of HDL particles.

The effect of energy-matched exercise intensity on brain-derived neurotrophic factor and motor learning.

BACKGROUND: Pairing a bout of high-intensity exercise with motor task practice can enhance motor learning beyond task practice alone, which is thought, in part, to be facilitated by an exercise-related increase in brain-derived neurotrophic factor (BDNF). The purpose of the current study was to examine the effect of different exercise intensities on BDNF levels and motor learning while controlling for exercise-related energy expenditure. METHODS: Forty-eight young, healthy participants were assigned to one of three groups: high-intensity exercise [High], low-intensity exercise [Low], or quiet rest [Rest]. The duration of the exercise bouts were individually adjusted so that each participant expended 200 kcals regardless of exercise intensity. BDNF was measured before and after exercise or rest. After exercise or rest, all participants practiced a 3-dimensional motor learning task, which involved reach movements made to sequentially presented targets. Retention was tested after 24-h. BDNF genotype was determined for each participant to explore its effects on BDNF and motor learning. RESULTS: All participants equally improved performance, indicated by a reduction in time to complete the task. However, the kinematic profile used to control the reach movement differed by group. The Rest group travelled the shortest distance between the targets, the High group had higher reach speed (peak velocity), and the Low group had earlier peak velocities. The rise in BDNF post-exercise was not significant, regardless of exercise intensity, and the change in BDNF was not associated with motor learning. The BDNF response to exercise did not differ by genotype. However, performance differed between those with the polymorphism (Met carriers) and those without (Val/Val). Compared to the Val/Val genotype, Met carriers had faster response times throughout task practice, which was supported by higher reach speeds and earlier peak velocities. CONCLUSION: Results indicated that both low and high-intensity exercise can alter the kinematic approach used to complete a reach task, and these changes appear unrelated to a change in BDNF. In addition, the BDNF genotype did not influence BDNF concentration, but it did have an effect on motor performance of a sequential target reach task.

Genomic and transcriptomic predictors of response levels to endurance exercise training.

Predicting the responsiveness to regular exercise is a topic of great relevance due to its potential role in personalized exercise medicine applications. The present review focuses on cardiorespiratory fitness (commonly measured by maximal oxygen uptake, V̇O2 max ), a trait with wide-ranging impact on health and performance indicators. Gains in V̇O2 max demonstrate large inter-individual variation even in response to standardized exercise training programmes. The estimated ΔVO2 max heritability of 47% suggests that genomic-based predictors alone are insufficient to account for the total trainability variance. Candidate gene and genome-wide linkage studies have not significantly contributed to our understanding of the molecular basis of trainability. A genome-wide association study suggested that V̇O2 max trainability is influenced by multiple genes of small effects, but these findings still await rigorous replication. Valuable evidence, however, has been obtained by combining skeletal muscle transcript abundance profiles with common DNA variants for the prediction of the V̇O2 max response to exercise training. Although the physiological determinants of V̇O2 max measured at a given time are largely enunciated, what is poorly understood are the details of tissue-specific molecular mechanisms that limit V̇O2 max and related signalling pathways in response to exercise training. Bioinformatics explorations based on thousands of variants have been used to interrogate pathways and systems instead of single variants and genes, and the main findings, along with those from exercise experimental studies, have been summarized here in a working model of V̇O2 max trainability.

Are there genetic paths common to obesity, cardiovascular disease outcomes, and cardiovascular risk factors?

Clustering of obesity, coronary artery disease, and cardiovascular disease risk factors is observed in epidemiological studies and clinical settings. Twin and family studies have provided some supporting evidence for the clustering hypothesis. Loci nearest a lead single nucleotide polymorphism (SNP) showing genome-wide significant associations with coronary artery disease, body mass index, C-reactive protein, blood pressure, lipids, and type 2 diabetes mellitus were selected for pathway and network analyses. Eighty-seven autosomal regions (181 SNPs), mapping to 56 genes, were found to be pleiotropic. Most pleiotropic regions contained genes associated with coronary artery disease and plasma lipids, whereas some exhibited coaggregation between obesity and cardiovascular disease risk factors. We observed enrichment for liver X receptor (LXR)/retinoid X receptor (RXR) and farnesoid X receptor/RXR nuclear receptor signaling among pleiotropic genes and for signatures of coronary artery disease and hepatic steatosis. In the search for functionally interacting networks, we found that 43 pleiotropic genes were interacting in a network with an additional 24 linker genes. ENCODE (Encyclopedia of DNA Elements) data were queried for distribution of pleiotropic SNPs among regulatory elements and coding sequence variations. Of the 181 SNPs, 136 were annotated to ≥ 1 regulatory feature. An enrichment analysis found over-representation of enhancers and DNAse hypersensitive regions when compared against all SNPs of the 1000 Genomes pilot project. In summary, there are genomic regions exerting pleiotropic effects on cardiovascular disease risk factors, although only a few included obesity. Further studies are needed to resolve the clustering in terms of DNA variants, genes, pathways, and actionable targets.

Uncovering physiological mechanisms for health disparities in type 2 diabetes.

Type 2 diabetes (T2D) prevalence in the United States is significantly higher in African Americans vs Whites. Yet, the physiological mechanisms contributing to this health disparity have been poorly described. To design effective strategies to reduce this disparity, there is a need to determine whether racial differences in diabetes prevalence are attributable to modifiable or non-modifiable factors. This review synthesizes and critically evaluates the potential physiological and genetic mechanisms that may contribute to the higher susceptibility of African Americans to T2D. These mechanisms include: 1) obesity and fat distribution; 2) metabolic flexibility; 3) muscle physiology; 4) energy expenditure and fitness; and 5) genetics. We focus on the clinical significance of findings and limitations of the recent literature.

Genomic and transcriptomic predictors of triglyceride response to regular exercise.

AIM: We performed genome-wide and transcriptome-wide profiling to identify genes and single nucleotide polymorphisms (SNPs) associated with the response of triglycerides (TG) to exercise training. METHODS: Plasma TG levels were measured before and after a 20-week endurance training programme in 478 white participants from the HERITAGE Family Study. Illumina HumanCNV370-Quad v3.0 BeadChips were genotyped using the Illumina BeadStation 500GX platform. Affymetrix HG-U133+2 arrays were used to quantitate gene expression levels from baseline muscle biopsies of a subset of participants (N=52). Genome-wide association study (GWAS) analysis was performed using MERLIN, while transcriptomic predictor models were developed using the R-package GALGO. RESULTS: The GWAS results showed that eight SNPs were associated with TG training-response (ΔTG) at p<9.9×10(-6), while another 31 SNPs showed p values <1×10(-4). In multivariate regression models, the top 10 SNPs explained 32.0% of the variance in ΔTG, while conditional heritability analysis showed that four SNPs statistically accounted for all of the heritability of ΔTG. A molecular signature based on the baseline expression of 11 genes predicted 27% of ΔTG in HERITAGE, which was validated in an independent study. A composite SNP score based on the top four SNPs, each from the genomic and transcriptomic analyses, was the strongest predictor of ΔTG (R(2)=0.14, p=3.0×10(-68)). CONCLUSIONS: Our results indicate that skeletal muscle transcript abundance at 11 genes and SNPs at a number of loci contribute to TG response to exercise training. Combining data from genomics and transcriptomics analyses identified a SNP-based gene signature that should be further tested in independent samples.

Left ventricle function and post-transcriptional events with exercise training in pigs.

BACKGROUND: Standardized exercise protocols have been shown to improve overall cardiovascular fitness, but direct effects on left ventricular (LV) function, particularly diastolic function and relation to post-transcriptional molecular pathways (microRNAs (miRs)) are poorly understood. This project tested the central hypothesis that adaptive LV remodeling resulting from a large animal exercise training protocol, would be directly associated with specific miRs responsible for regulating pathways relevant to LV myocardial stiffness and geometry. METHODS AND RESULTS: Pigs (n = 9; 25 Kg) underwent a 4 week exercise training protocol (10 degrees elevation, 2.5 mph, 10 min, 5 days/week) whereby LV chamber stiffness (KC) and regional myocardial stiffness (rKm) were measured by Doppler/speckle tracking echocardiography. Age and weight matched non-exercise pigs (n = 6) served as controls. LV KC fell by approximately 50% and rKm by 30% following exercise (both p < 0.05). Using an 84 miR array, 34 (40%) miRs changed with exercise, whereby 8 of the changed miRs (miR-19a, miR-22, miR-30e, miR-99a, miR-142, miR-144, miR-199a, and miR-497) were correlated to the change in KC (r ≥ 0.5 p < 0.05) and mapped to matrix and calcium handling processes. Additionally, miR-22 and miR-30e decreased with exercise and mapped to a localized inflammatory process, the inflammasome (NLRP-3, whereby a 2-fold decrease in NLRP-3 mRNA occurred with exercise (p < 0.05). CONCLUSION: Chronic exercise reduced LV chamber and myocardial stiffness and was correlated to miRs that map to myocardial relaxation processes as well as local inflammatory pathways. These unique findings set the stage for utilization of myocardial miR profiling to identify underlying mechanisms by which exercise causes changes in LV myocardial structure and function.

Associations of an HDL apolipoproteomic index with cardiometabolic risk factors before and after exercise training in the HERITAGE Family Study.

BACKGROUND AND AIMS: Previous studies have derived and validated an HDL apolipoproteomic score (pCAD) that predicts coronary artery disease (CAD) risk. However, the associations between pCAD and markers of cardiometabolic health in healthy adults are not known, nor are the effects of regular exercise on pCAD. METHODS: A total of 641 physically inactive adults free of cardiovascular disease from the HERITAGE Family Study completed 20 weeks of exercise training. The pCAD index (range 0-100) was calculated using measurements of apolipoproteins A-I, C-I, C-II, C-III, and C-IV from ApoA-I-tagged serum (higher index = higher CAD risk). The associations between pCAD index and cardiometabolic traits at baseline and their training responses were assessed with Spearman correlation and general linear models. A Bonferroni correction of p < 8.9 × 10-04 was used to determine statistical significance. RESULTS: The mean ± SD baseline pCAD index was 29 ± 32, with 106 (16.5 %) participants classified as high CAD risk. At baseline, pCAD index was positively associated with blood pressure, systemic inflammation, and body composition. HDL size, VO2max, and HDL-C were negatively associated with pCAD index at baseline. Of those classified as high CAD risk at baseline, 52 (49 %) were reclassified as normal risk after training. Following training, pCAD index changes were inversely correlated (p < 1.4 × 10-04) with changes in HDL-C, HDL size, and LDL size. CONCLUSIONS: A higher pCAD index was associated with a worse cardiometabolic profile at baseline but improved with regular exercise. The results from this study highlight the potential role of HDL apolipoproteins as therapeutic targets for lifestyle interventions, particularly in high-risk individuals.