Aerobic training-mediated DNA hypermethylation of Agtr1a and Mas1 genes ameliorate mesenteric arterial function in spontaneously hypertensive rats.

BACKGROUND: The imbalance of vasoconstrictor and vasodilator axes of the renin-angiotensin system (RAS) is observed in hypertension. Exercise regulates RAS level and improves vascular function. This study focused on the contribution of RAS axes in vascular function of mesenteric arteries and exercise-induced DNA methylation of the Agtr1a (AT1aR) and Mas1 (MasR) genes in hypertension. METHODS: Spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats were randomized into exercise or sedentary group. Levels of plasma RAS components, vascular tone, and DNA methylation markers were measured. RESULTS: Blood pressure of SHR was markedly reduced after 12 weeks of aerobic exercise. RAS peptides in plasma were all increased with an imbalanced upregulation of Ang II and Ang-(1-7) in SHR, exercise revised the level of RAS and increased Ang-(1-7)/Ang II. The vasoconstriction response induced by Ang II was mainly via type 1 receptors (AT1R), while this contraction was inhibited by Mas receptor (MasR). mRNA and protein of AT1R and MasR were both upregulated in SHR, whereas exercise significantly suppressed this imbalanced increase and increased MasR/AT1R ratio. Exercise hypermethylated Agtr1a and Mas1 genes, associating with increased DNMT1 and DNMT3b and SAM/SAH. CONCLUSIONS: Aerobic exercise ameliorates vascular function via hypermethylation of the Agtr1a and Mas1 genes and restores the vasoconstrictor and vasodilator axes balance.

Acute Cycling Exercise Induces Changes in Red Blood Cell Deformability and Membrane Lipid Remodeling.

Here we describe the effects of a controlled, 30 min, high-intensity cycling test on blood rheology and the metabolic profiles of red blood cells (RBCs) and plasma from well-trained males. RBCs demonstrated decreased deformability and trended toward increased generation of microparticles after the test. Meanwhile, metabolomics and lipidomics highlighted oxidative stress and activation of membrane lipid remodeling mechanisms in order to cope with altered properties of circulation resulting from physical exertion during the cycling test. Of note, intermediates from coenzyme A (CoA) synthesis for conjugation to fatty acyl chains, in parallel with reversible conversion of carnitine and acylcarnitines, emerged as metabolites that significantly correlate with RBC deformability and the generation of microparticles during exercise. Taken together, we propose that RBC membrane remodeling and repair plays an active role in the physiologic response to exercise by altering RBC properties.

T helper cell-related changes in peripheral blood induced by progressive effort among soccer players.

OBJECTIVES: The regulatory mechanisms affecting the modulation of the immune system accompanying the progressive effort to exhaustion, particularly associated with T cells, are not fully understood. We analysed the impact of two progressive effort protocols on T helper (Th) cell distribution and selected cytokines. METHODS: Sixty-two male soccer players with a median age of 17 (16-29) years performed different protocols for progressive exercise until exhaustion: YO-YO (YYRL1) and Beep. Blood samples for all analyses were taken three times: at baseline, post-effort, and in recovery. RESULTS: The percentage of Th1 cells increased post-effort and in recovery. The post-effort percentage of Th1 cells was higher in the Beep group compared to the YYRL1 group. Significant post-effort increase in Th17 cells was observed in both groups. The post-effort percentage of regulatory T cells (Treg) increased in the Beep group. An increased post-effort concentration of IL-2, IL-6, IL-8 and IFN-γ in both groups was observed. Post-effort TNF-α and IL-10 levels were higher than baseline in the YYRL1 group, while the post-effort IL-17A concentration was lower than baseline only in the Beep group. The recovery IL-2, IL-4, TNF-α and IFN-γ levels were higher than baseline in the YYRL1 group. The recovery IL-4, IL-6, IL-8, TNF-α and IFN-γ values were higher than baseline in the Beep group. CONCLUSION: The molecular patterns related to cytokine secretion are not the same between different protocols for progressive effort. It seems that Treg cells are probably the key cells responsible for silencing the inflammation and enhancing anti-inflammatory pathways.

Tlr4 participates in the responses of markers of apoptosis, inflammation, and ER stress to different acute exercise intensities in mice hearts.

BACKGROUND: Toll-like receptor 4 (Tlr4) is recognized due to its role in the immune response. Also, this protein can participate in the signaling pathway of events triggered by physical exercise such as apoptosis, inflammation, and endoplasmic reticulum (ER) stress. The main objective of this study was to evaluate the role of Tlr4 in the markers of these events in the myocardium of mice submitted to acute physical exercise (APE) protocols at different intensities. METHODS: Echocardiogram, RT-qPCR, and immunoblotting technique were used to evaluate the left ventricle of wild-type (WT) and Tlr4 knockout (Tlr4 KO) submitted to APE protocols at 45, 60, and 75% of their maximal velocity. Also, we performed the bioinformatics analysis to establish the connection of heart mRNA levels of Tlr4 with heart genes of inflammation and ER stress of several isogenic strains of BXD mice. RESULTS: Under basal conditions, the Tlr4 deletion diminished the performance, and expression of inflammation and ER stress genes in the left ventricle, but increased the serum levels of CK, Il-17, and Tnf-alpha. Under the same exercise conditions, the Tlr4 deletion reduced the glycemia, serum levels of CK, Il-17, and Tnf-alpha, as well as genes and/or proteins related to apoptosis, inflammation and ER stress in the left ventricle, but increased the levels of CK-mb and LDH, as well as other genes related to apoptosis, inflammation, and ER stress in the left ventricle. CONCLUSION: Altogether, the current findings highlighted the effects of different acute exercise intensities were attenuated in the heart of Tlr4 KO mice.

Effect of hyperoxia on the immune status of oxygen divers and endurance athletes.

Physical activity, particularly that, exerted by endurance athletes, impacts the immune status of the human body. Prolonged duration and high-intensity endurance training lead to increased production of reactive oxygen species (ROS) and thereby to oxidative stress. Military combat swimmers (O2-divers) are regularly exposed to hyperbaric hyperoxia (HBO) in addition to intensive endurance training intervals. They are, therefore, exposed to extreme levels of oxidative stress. Several studies support that the intensity of oxidative stress essentially determines the effect on immune status. The aim of this study was to comparatively characterise peripheral blood mononuclear cells (PBMCs) of O2-divers (military combat swimmers), endurance athletes (amateur triathletes), and healthy control volunteers with respect to DNA fragmentation, immune status and signs of inflammation. Furthermore, it was investigated how PBMCs from these groups responded acutely to exposure to HBO. We showed that DNA fragmentation was comparable in PBMCs of all three groups under basal conditions directly after HBO exposure. However, significantly higher DNA fragmentation was observed in O2-divers 18 hours after HBO, possibly indicating a slower recovery. O2-divers also exhibited a proinflammatory immune status exemplified by an elevated number of CD4+CD25+ T cells, elevated expression of proinflammatory cytokine IL-12, and diminished expression of anti-inflammatory TGF-ß1 compared to controls. Supported by a decreased basal gene expression and prolonged upregulation of anti-oxidative HO-1, these data suggest that higher oxidative stress levels, as present under intermitted hyperbaric hyperoxia, e.g. through oxygen diving, promote a higher inflammatory immune status than oxidative stress through endurance training alone.

Learning one's genetic risk changes physiology independent of actual genetic risk.

Millions of people now access personal genetic risk estimates for diseases such as Alzheimer's, cancer and obesity1. While this information can be informative2-4, research on placebo and nocebo effects5-8 suggests that learning of one's genetic risk may evoke physiological changes consistent with the expected risk profile. Here we tested whether merely learning of one's genetic risk for disease alters one's actual risk by making people more likely to exhibit the expected changes in gene-related physiology, behaviour and subjective experience. Individuals were genotyped for actual genetic risk and then randomly assigned to receive either a 'high-risk' or 'protected' genetic test result for obesity via cardiorespiratory exercise capacity (experiment 1, N = 116) or physiological satiety (experiment 2, N = 107) before engaging in a task in which genetic risk was salient. Merely receiving genetic risk information changed individuals' cardiorespiratory physiology, perceived exertion and running endurance during exercise, and changed satiety physiology and perceived fullness after food consumption in a self-fulfilling manner. Effects of perceived genetic risk on outcomes were sometimes greater than the effects associated with actual genetic risk. If simply conveying genetic risk information can alter actual risk, clinicians and ethicists should wrestle with appropriate thresholds for when revealing genetic risk is warranted.

Physical exertion exacerbates decline in the musculature of an animal model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a genetic disorder caused by loss of the protein dystrophin. In humans, DMD has early onset, causes developmental delays, muscle necrosis, loss of ambulation, and death. Current animal models have been challenged by their inability to model the early onset and severity of the disease. It remains unresolved whether increased sarcoplasmic calcium observed in dystrophic muscles follows or leads the mechanical insults caused by the muscle's disrupted contractile machinery. This knowledge has important implications for patients, as potential physiotherapeutic treatments may either help or exacerbate symptoms, depending on how dystrophic muscles differ from healthy ones. Recently we showed how burrowing dystrophic (dys-1) C. elegans recapitulate many salient phenotypes of DMD, including loss of mobility and muscle necrosis. Here, we report that dys-1 worms display early pathogenesis, including dysregulated sarcoplasmic calcium and increased lethality. Sarcoplasmic calcium dysregulation in dys-1 worms precedes overt structural phenotypes (e.g., mitochondrial, and contractile machinery damage) and can be mitigated by reducing calmodulin expression. To learn how dystrophic musculature responds to altered physical activity, we cultivated dys-1 animals in environments requiring high intensity or high frequency of muscle exertion during locomotion. We find that several muscular parameters (e.g., size) improve with increased activity. However, longevity in dystrophic animals was negatively associated with muscular exertion, regardless of effort duration. The high degree of phenotypic conservation between dystrophic worms and humans provides a unique opportunity to gain insight into the pathology of the disease as well as the initial assessment of potential treatment strategies.

I Smell a Mouse: Indirect Genetic Effects on Voluntary Wheel-Running Distance, Duration and Speed.

Indirect genetic effects (IGEs; the heritable influence of one organism on a conspecific) can affect the evolutionary dynamics of complex traits, including behavior. Voluntary wheel running is an important model system in quantitative genetic studies of behavior, but the possibility of IGEs on wheel running and its components (time spent running and average running speed) has not been examined. Here, we analyze a dataset from a replicated selection experiment on wheel running (11,420 control and 26,575 selected mice measured over 78 generations) in which the standard measurement protocol allowed for the possibility of IGEs occurring through odors because mice were provided with clean cages attached to a clean wheel or a wheel previously occupied by another mouse for 6 days. Overall, mice ran less on previously occupied wheels than on clean wheels, and they ran significantly less when following a male than a female. Significant interactions indicated that the reduction in running was more pronounced for females than males and for mice from selected lines than control mice. Pedigree-based "animal model" analyses revealed significant IGEs for running distance (the trait under selection), with effect sizes considerably higher for the initial/exploratory phase (i.e., first two of six test days). Our results demonstrate that IGEs can occur in mice interacting through scent only, possibly because they attempt to avoid conspecifics.

Impact of ACE I/D gene polymorphism on blood pressure, heart rate variability and nitric oxide responses to the aerobic exercise in hypertensive elderly / Impacto del polimorfismo I/D del gen de la Enzima Conversora de la Angiotensina en la presión sanguínea, variacion de la frecuencia cardíaca y óxido nítrico en respuesta a ejercicios aeróbicos en mayores hipertensos / Impacto do polimorfismo I/D do gene da ECA nas respostas de pressão arterial, variabilidade da frequência cardíaca e óxido nítrico ao exercício aeróbio em idosas hipertensas

Objective. To analyze the impact of I/D polymorphism of the angiotensin-converting enzyme gene on the responses of 24 h blood pressure, heart rate variability and nitric oxide after moderate aerobic exercise session. Method. Twenty seven hypertensive elderly were genotyped for the I/D polymorphism of the angiotensin-converting enzyme gene (D/D: n=9; I/D: n=9; I/I: n=9) and performed a bout of aerobic exercise at 90% of anaerobic threshold. Measurements of mean blood pressure, heart rate variability and nitric oxide were performed before and during 24h post-aerobic exercise session. Results. The D/D genotype showed impaired mean arterial pressure responses (elevation) in the nocturnal sleep (10:30pm to 06:30am) post-aerobic exercise when compared to rest (D/D= -4.2±8.1mmHg; p>0.05, I/D=-9.2±9.1mmHg; p<0.05 and I/I=-7.0±6.9mmHg; p<0.05). Besides, in day time of 06:30am to 10:30am (next day) higher values of mean arterial pressure responses occur between D/D=4.7±4.6mmHg vs. I/D=−2.0±13.0mmHg; p<0.05. The carriers of the D allele, in addition to not release nitric oxide significantly post-aerobic exercise session (p>0.05), showed reduced elevation of nitric oxide between genotypes immediately after aerobic exercise (D/D=12.8±135.3μM and I/D=-8.7±69.0μM vs. I/I=132.9±188.7μM; p<0.05). Reduced elevation of heart rate variability post-aerobic exercise session occurred when compared to rest (D/D=1h: -0.08±0.09s; p<0.05 and 24h: -0.08±0.11s; p<0.05). Conclusion. Elderly hypertensive individuals carrying the D/D genotype of the angiotensin converting enzyme gene showed impaired responses of blood pressure post-aerobic exercise, especially during sleep, and reduced heart rate variability during the 24h post-aerobic exercise. Besides, to angiotensin converting enzyme genotypes with the presence of D allele (D/D and I/D) was impaired release of nitric oxide post-aerobic exercise session

Objetivo. Analizar el impacto del polimorfismo I/D del gen de la enzima conversora de la angiotensina en la presión sanguínea, variación de la frecuencia cardíaca y óxido nítrico durante 24h en espuesta a una batería moderada de ejercicios aeróbicos. Método. Veintisiete ancianas hipertensas fueron genotipadas para el polimorfismo I/D del gen de la enzima conversora de la angiotensina (D/D: n=9; I/D: n=9; I/I: n=9) y realizaron una batería de ejercicios aeróbicos al 90% del umbral anaeróbico. Se realizaron medidas de la presión arterial media, variabilidad de la frecuencia cardíaca y óxido nítrico, antes y durante las 24h siguientes después de una sesión de ejercicios aeróbicos. Resultados. El genotipo D/D presentó una respuesta inadecuada de la presión arterial media (aumento) durante el sueño nocturno después del ejercicio (22:30-06:30) en comparación con el reposo (D/D=-4.2±8.1mmHg; p>0.05, I/D=-9.2±9.1mmHg; p<0.05 and I/I=-7.0±6.9mmHg; p<0.05). Por otro lado, durante el día, de 06:30 hasta las 10:30 de la mañana (del día siguinete) se registraron valores elevados del aumento de la presión arterial media en el genotipo D/D=4.7±4.6mmHg vs. I/D=-2.0±13.0mmHg; p<0.05. Las portadoras del alelo D, más allá de no mostrar significación en los niveles de óxido nítrico después de la sesión de ejercicio, mostraron una reducción del incremento de óxido nítrico entre los genotipos después del ejercicio aeróbico (D/D=12.8±135.3μM y I/D=-8.7±69.0μM vs. I/I=132.9±188.7μM; p<0.05)...

Objetivo. Analisar o impacto do polimorfismo I/D do gene da enzima conversora da angiotensina na pressão sanguínea, variabilidade da frequência cardíaca e óxido nítrico durante 24h, em resposta a uma bateria moderada de exercícios aeróbicos. Método. Vinte e sete idosas hipertensas foram genotipadas para o polimorfismo I/D do gene da enzima conversora da angiotensina (D/D: n=9; I/D: n=9; I/I: n=9) e realizaram uma sessão de exercício aeróbio à 90% do limiar anaeróbio. Medidas de pressão arterial média, variabilidade da frequência cardíaca e óxido nítrico foram coletadas antes e durante as 24h seguintes, após a sessão de exercício aeróbio. Resultados. O genótipo D/D mostrou uma resposta inadequada da pressão arterial média (elevação) durante o sono após o exercício (22:30-06:30) em comparação ao repouso (D/D=-4.2±8.1mmHg; p>0.05, I/D=-9.2±9.1mmHg; p<0.05 e I/I=-7.0±6.9mmHg; p<0.05). Além disso, durante o dia, de 06:30-10:30da manhã (do dia seguinte), maiores valores de pressão arterial média ocorreram entre D/D=4.7±4.6mmHg vs. I/D=-2.0±13.0mmHg; p<0.05. O grupo carreador do alelo D, além de não revelar significância no óxido nítrico após a sessão de exercício, mostrou uma redução da elevação do óxido nítrico entre os genótipos logo após o exercício aeróbio (D/D=12.8±135.3μM e I/D=-8.7±69.0μM vs. I/I=132.9±188.7μM; p<0.05). Ocorreu uma redução do R-Ri após os exercícios quando comparada com os valores do repouso (D/D=1h: -0.08±0.09s; p<0.05 e 24h: -0.08±0.11s; p<0.05). Conclusão. Indivíduos idosos e hipertensos carreadores do genótipo D/D para o gene da enzima conversora da angiotensina mostraram resposta inadequada de pressão arterial pós-exercício aeróbio, especialmente durante o sono, e reduzida variabilidade da frequência cardíaca durante as 24h seguintes pós-exercício. Além disso, o genótipo da enzima conversora da angiotensina com a presença do alelo D (D/D e I/D) teve sua liberação de óxido nítrico prejudicada nos momentos após a sessão de exercício aeróbio

High motivation for exercise is associated with altered chromatin regulators of monoamine receptor gene expression in the striatum of selectively bred mice.

Although exercise is critical for health, many lack the motivation to exercise, and it is unclear how motivation might be increased. To uncover the molecular underpinnings of increased motivation for exercise, we analyzed the transcriptome of the striatum in four mouse lines selectively bred for high voluntary wheel running and four non-selected control lines. The striatum was dissected and RNA was extracted and sequenced from four individuals of each line. We found multiple genes and gene systems with strong relationships to both selection and running history over the previous 6 days. Among these genes were Htr1b, a serotonin receptor subunit and Slc38a2, a marker for both glutamatergic and γ-aminobutyric acid (GABA)-ergic signaling. System analysis of the raw results found enrichment of transcriptional regulation and kinase genes. Further, we identified a splice variant affecting the Wnt-related Golgi signaling gene Tmed5. Using coexpression network analysis, we found a cluster of interrelated coexpression modules with relationships to running behavior. From these modules, we built a network correlated with running that predicts a mechanistic relationship between transcriptional regulation by nucleosome structure and Htr1b expression. The Library of Integrated Network-Based Cellular Signatures identified the protein kinase C δ inhibitor, rottlerin, the tyrosine kinase inhibitor, Linifanib and the delta-opioid receptor antagonist 7-benzylidenenaltrexone as potential compounds for increasing the motivation to run. Taken together, our findings support a neurobiological framework of exercise motivation where chromatin state leads to differences in dopamine signaling through modulation of both the primary neurotransmitters glutamate and GABA, and by neuromodulators such as serotonin.

Voluntary wheel running reduces voluntary consumption of ethanol in mice: identification of candidate genes through striatal gene expression profiling.

Hedonic substitution, where wheel running reduces voluntary ethanol consumption, has been observed in prior studies. Here, we replicate and expand on previous work showing that mice decrease voluntary ethanol consumption and preference when given access to a running wheel. While earlier work has been limited mainly to behavioral studies, here we assess the underlying molecular mechanisms that may account for this interaction. From four groups of female C57BL/6J mice (control, access to two-bottle choice ethanol, access to a running wheel, and access to both two-bottle choice ethanol and a running wheel), mRNA-sequencing of the striatum identified differential gene expression. Many genes in ethanol preference quantitative trait loci were differentially expressed due to running. Furthermore, we conducted Weighted Gene Co-expression Network Analysis and identified gene networks corresponding to each effect behavioral group. Candidate genes for mediating the behavioral interaction between ethanol consumption and wheel running include multiple potassium channel genes, Oprm1, Prkcg, Stxbp1, Crhr1, Gabra3, Slc6a13, Stx1b, Pomc, Rassf5 and Camta2. After observing an overlap of many genes and functional groups previously identified in studies of initial sensitivity to ethanol, we hypothesized that wheel running may induce a change in sensitivity, thereby affecting ethanol consumption. A behavioral study examining Loss of Righting Reflex to ethanol following exercise trended toward supporting this hypothesis. These data provide a rich resource for future studies that may better characterize the observed transcriptional changes in gene networks in response to ethanol consumption and wheel running.

Safety of American Heart Association-recommended minimum exercise for desmosomal mutation carriers.

BACKGROUND: Endurance exercise is associated with adverse outcomes in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Exercise recommendations for family members remain undetermined. OBJECTIVE: The purposes of this study were to determine if (1) endurance exercise (Bethesda class C) and exercise intensity (metabolic equivalent hours per year [MET-Hr/year]) increase the likelihood of fulfilling 2010 Task Force Criteria and ventricular arrhythmias/implantable cardioverter-defibrillator shock (ventricular tachycardia/ventricular fibrillation [VT/VF]), and (2) exercise restriction to the American Heart Association (AHA)-recommended minimum for healthy adults is associated with favorable outcomes of at-risk family members. METHODS: Twenty-eight family members of 10 probands inheriting a PKP2 mutation were interviewed about exercise from age 10. Exercise threshold to maintain overall health was based on the 2007 AHA guidelines of a minimum 390 to 650 MET-Hr/year. RESULTS: After adjustment for age, sex, and family membership, both participation in endurance athletics (odds ratio [OR] 7.4, P = .03) and higher-intensity exercise (OR = 4.2, P = .004) were associated with diagnosis (n = 13). Endurance athletes were also significantly more likely to develop VT/VF (n = 6, P = .02). Family members who restricted exercise at or below the upper bound of the AHA goal (≤650 MET-Hr/year) were significantly less likely to be diagnosed (OR = 0.07, P = .002) and had no VT/VF. At diagnosis and first VT/VF, family members had accumulated 2.8-fold (P = .002) and 3.5-fold (P = .03), respectively, greater MET-Hr exercise than the AHA-recommended minimum. Those who developed VT/VF had performed particularly high-intensity exercise in adolescence compared to unaffected family members (age 10-14: P = .04; age 14-19: P = .02). CONCLUSION: The results of this study suggest restricting unaffected desmosomal mutation carriers from endurance and high-intensity athletics but potentially not from AHA-recommended minimum levels of exercise for healthy adults.

Selective Life-Long Skeletal Myofiber-Targeted VEGF Gene Ablation Impairs Exercise Capacity in Adult Mice.

Exercise is dependent on adequate oxygen supply for mitochondrial respiration in both cardiac and locomotor muscle. To determine whether skeletal myofiber VEGF is critical for regulating exercise capacity, independent of VEGF function in the heart, ablation of the VEGF gene was targeted to skeletal myofibers (skmVEGF-/-) during embryogenesis (∼ E9.5), leaving intact VEGF expression by all other cells in muscle. In adult mice, VEGF levels were decreased in the soleus (by 65%), plantaris (94%), gastrocnemius (74%), EDL (99%) and diaphragm (64%) (P < 0.0001, each muscle). VEGF levels were unchanged in the heart. Treadmill speed (WT 86 ± 4 cm/sec, skmVEGF-/- 70 ± 5 cm/sec, P = 0.006) and endurance (WT 78 ± 24 min, skmVEGF-/- 18 ± 4 min, P = 0.0004) were severely limited in skmVEGF-/- mice in contrast to minor effect of conditional skmVEGF gene deletion in the adult. Body weight was also reduced (WT 22.8 ± 1.6 g, skmVEGF-/-, 21.1 ± 1.5, P = 0.02), but the muscle mass/body weight ratio was unchanged. The capillary/fiber ratio was lower in skmVEGF-/- plantaris (WT 1.51 ± 0.12, skmVEGF-/- 1.16 ± 0.20, P = 0.01), gastrocnemius (WT 1.61 ± 0.08, skmVEGF-/- 1.39 ± 0.08, P = 0.01), EDL (WT 1.36 ± 0.07, skmVEGF-/- 1.14 ± 0.13, P = 0.03) and diaphragm (WT 1.39 ± 0.18, skmVEGF-/- 0.79 ± 0.16, P = 0.0001) but, not in soleus. Cardiac function (heart rate, maximal pressure, maximal dP/dt, minimal dP/dt,) in response to dobutamine was not impaired in anesthetized skmVEGF-/- mice. Isolated soleus and EDL fatigue times were 16% and 20% (P < 0.02) longer, respectively, in skmVEGF-/- mice than the WT group. These data suggest that skeletal myofiber VEGF expressed during development is necessary to establish capillary networks that allow maximal exercise capacity.

Exercise Capacity and Response to Training Quantitative Trait Loci in a NZW X 129S1 Intercross and Combined Cross Analysis of Inbred Mouse Strains.

Genetic factors determining exercise capacity and the magnitude of the response to exercise training are poorly understood. The aim of this study was to identify quantitative trait loci (QTL) associated with exercise training in mice. Based on marked differences in training responses in inbred NZW (-0.65 ± 1.73 min) and 129S1 (6.18 ± 3.81 min) mice, a reciprocal intercross breeding scheme was used to generate 285 F2 mice. All F2 mice completed an exercise performance test before and after a 4-week treadmill running program, resulting in an increase in exercise capacity of 1.54 ± 3.69 min (range = -10 to +12 min). Genome-wide linkage scans were performed for pre-training, post-training, and change in run time. For pre-training exercise time, suggestive QTL were identified on Chromosomes 5 (57.4 cM, 2.5 LOD) and 6 (47.8 cM, 2.9 LOD). A significant QTL for post-training exercise capacity was identified on Chromosome 5 (43.4 cM, 4.1 LOD) and a suggestive QTL on Chromosomes 1 (55.7 cM, 2.3 LOD) and 8 (66.1 cM, 2.2 LOD). A suggestive QTL for the change in run time was identified on Chromosome 6 (37.8 cM, 2.7 LOD). To identify shared QTL, this data set was combined with data from a previous F2 cross between B6 and FVB strains. In the combined cross analysis, significant novel QTL for pre-training exercise time and change in exercise time were identified on Chromosome 12 (54.0 cM, 3.6 LOD) and Chromosome 6 (28.0 cM, 3.7 LOD), respectively. Collectively, these data suggest that combined cross analysis can be used to identify novel QTL and narrow the confidence interval of QTL for exercise capacity and responses to training. Furthermore, these data support the use of larger and more diverse mapping populations to identify the genetic basis for exercise capacity and responses to training.

Constant light enhances synchrony among circadian clock cells and promotes behavioral rhythms in VPAC2-signaling deficient mice.

Individual neurons in the suprachiasmatic nuclei (SCN) contain an intracellular molecular clock and use intercellular signaling to synchronize their timekeeping activities so that the SCN can coordinate brain physiology and behavior. The neuropeptide vasoactive intestinal polypeptide (VIP) and its VPAC2 receptor form a key component of intercellular signaling systems in the SCN and critically control cellular coupling. Targeted mutations in either the intracellular clock or intercellular neuropeptide signaling mechanisms, such as VIP-VPAC2 signaling, can lead to desynchronization of SCN neuronal clocks and loss of behavioral rhythms. An important goal in chronobiology is to develop interventions to correct deficiencies in circadian timekeeping. Here we show that extended exposure to constant light promotes synchrony among SCN clock cells and the expression of ~24 h rhythms in behavior in mice in which intercellular signaling is disrupted through loss of VIP-VPAC2 signaling. This study highlights the importance of SCN synchrony for the expression of rhythms in behavior and reveals how non-invasive manipulations in the external environment can be used to overcome neurochemical communication deficits in this important brain system.

MicroRNA-761 regulates mitochondrial biogenesis in mouse skeletal muscle in response to exercise.

MicroRNAs (miRNAs) have been suggested to play critical roles in skeletal muscle in response to exercise. Previous study has shown that miR-761 was involved in a novel model regulating the mitochondrial network. However, its role in mitochondrial biogenesis remains poorly understood. Therefore, the current study was aimed to examine the effect of miR-761 on mitochondrial biogenesis in skeletal muscle. Real-time quantitative PCR analysis demonstrated that aberrantly expressed miR-761 is involved in exercise activity and miR-761 is decreased by exercise training compared with the sedentary control mice. miR-761 suppresses mitochondrial biogenesis of C2C12 myocytes by targeting the 3'-UTR of peroxisome proliferator-activated receptor gamma (PPARγ) coactivator-1 (PGC-1α). Overexpression of miR-761 was capable of inhibiting the protein expression levels of PGC-1α. Moreover, miR-761 overexpression suppressed the p38 MAPK signaling pathway and down-regulated the expression of phosphorylated MAPK-activated protein kinase-2 (P-MK2), a downstream kinase of p38 MAPK. The phosphorylation of activating transcription factors 2 (ATF2) that plays a functional role in linking the activation of the p38 MAPK pathway to enhanced transcription of the PGC-1α was also inhibited by the overexpression of miR-761. These findings revealed a novel regulation mechanism for miR-761 in skeletal myocytes, and contributed to a better understanding of the modulation of skeletal muscle in response to exercise.

Adipose triglyceride lipase deletion from adipocytes, but not skeletal myocytes, impairs acute exercise performance in mice.

Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme mediating triacylglycerol hydrolysis in virtually all cells, including adipocytes and skeletal myocytes, and hence, plays a critical role in mobilizing fatty acids. Global ATGL deficiency promotes skeletal myopathy and exercise intolerance in mice and humans, and yet the tissue-specific contributions to these phenotypes remain unknown. The goal of this study was to determine the relative contribution of ATGL-mediated triacylglycerol hydrolysis in adipocytes vs. skeletal myocytes to acute exercise performance. To achieve this goal, we generated murine models with adipocyte- and skeletal myocyte-specific targeted deletion of ATGL. We then subjected untrained mice to acute peak and submaximal exercise interventions and assessed exercise performance and energy substrate metabolism. Impaired ATGL-mediated lipolysis within adipocytes reduced peak and submaximal exercise performance, reduced peripheral energy substrate availability, shifted energy substrate preference toward carbohydrate oxidation, and decreased HSL Ser(660) phosphorylation and mitochondrial respiration within skeletal muscle. In contrast, impaired ATGL-mediated lipolysis within skeletal myocytes was not sufficient to reduce peak and submaximal exercise performance or peripheral energy substrate availability and instead tended to enhance metabolic flexibility during peak exercise. Furthermore, the expanded intramyocellular triacylglycerol pool in these mice was reduced following exercise in association with preserved HSL phosphorylation, suggesting that HSL may compensate for impaired ATGL action in skeletal muscle during exercise. These data suggest that adipocyte rather than skeletal myocyte ATGL-mediated lipolysis plays a greater role during acute exercise in part because of compensatory mechanisms that maintain lipolysis in muscle, but not adipose tissue, when ATGL is absent.

Factors associated with compliance with physical activity recommenddations among adolescents in Huesca / Factores asociados con el cumplimiento de las recomendaciones de actividad física entre los adolescentes dehuesca / Factores associados ao cumprimento das recomendações de actividade fisica entre adolescentes de huesca

Schools have been identified as environments of choice for physical activity promotion. This study examines factors associated with compliance with objectively assessed physical activity recommendations for early adolescents taking part in “Sigue la Huella”, a school-based intervention guided by a social ecological framework and Self-Determination Theory (Deci and Ryan, 2002). A total of 200 students (108 boys) aged 12-13 years (M = 12.16; SD = ± 0.51), wore accelerometers during a seven-day period and completed a questionnaire. Participants were considered compliant to the recommendations if their moderate to vigorous physical activity, averaged over seven days, was ≥ 60 minutes a day. As a result 57.4% of boys and 9.9% of girls met recommendations. In a multilevel logistic regression model, compliance was higher among boys and students attending private schools, and lower for obese students. Compliance was also associated with higher perceptions of physical competence, higher perceptions of autonomy in physical education, greater importance attached to physical education and less sedentary time. In conclusion, assessed objectively, gender differences in compliance with physical activity recommendations were greater than expected. Self-Determination Theory emerged as a useful framework to identify motivational factors that can be addressed in school-based physical activity interventions and programs for early adolescents

s centros escolares têm sido identificados como contextos privilegiados para a promoção da actividade física. Este estudo examina osfactores associados ao cumprimento das recomendações da actividade física avaliados objectivamente para os jovens adolescentes que integram o pro-grama “Sigue la Huella”, uma intervenção realizada em contexto escolar e baseada num marco teórico ecológico e na Teoria da Auto-determinação(Deci e Ryan, 2002). Um total de 200 estudantes (108 rapazes) de 12 e 13 anos (M= 12.16; DP= ± 0.51) usaram acelerómetros durante um período desete dias e preencheram um questionário. Os participantes eram considerados como cumpridores das recomendações se a sua actividade física mode-rada-vigorosa média era ≥ 60 e se mantinha durante os sete dias. Os resultados indicam que 57.4% dos rapazes e 9.9% das raparigas cumpriram as re-comendações. Através de um modelo multinível de regressão logística, constatou-se que o cumprimento foi superior entre os rapazes e os estudantes decolégios privados, e menor para os estudantes obesos. O cumprimento das recomendações também se associou a uma maior percepção de competênciafísica, uma maior percepção de autonomia em educação física, maior importância que se atribui à educação física e a um menor tempo sedentário. Emsuma, a partir da avaliação objectiva, as diferenças de género no cumprimento das recomendações de actividade física foram superiores ao esperado. ATeoria da Auto-Determinação configura-se como um marco útil para identificar os factores motivacionais que podem ser abordados nas intervenções eprogramas de actividade física no âmbito escolar para os jovens adolescentes

Los centros escolares han sido identificados como los entornos idoneos para la promoción de la actividad física. Este estudio examina los factores asociados con el cumplimiento de las recomendaciones de actividad física evaluados objetivamente para los jóvenes adolescentes que forman parte de "Sigue la Huella", una intervención basada en el entorno escolar guiada por un marco social ecológico y la teoría de la Autodeterminación (Deciy Ryan, 2002). Un total de 200 estudiantes (108 chicos) de 12 y 13 años (M = 12.16; DE = ± 0.51), llevaron acelerómetros durante un período de siete días y completaron un cuestionario. A los participantes se les consideraba conformes a las recomendaciones si su actividad física moderada-vigorosa, como promedio durante los siete días, era ≥ 60 minutos al día. Como resultado, el 57.4% de los chicos y el 9.9% de las chicas cumplieron las recomendaciones. En un modelo multinivel de regresión logística, el cumplimiento fue mayor entre los chicos y los estudiantes que asisten a colegios privados, y menor para los estudiantes obesos. El cumplimiento también se asoció con una mayor percepción de competencia física, una mayor percepción de la autonomía en la educación física, mayor importancia que se le concede a la educación física y con un menor tiempo sedentario. En conclusión, a partir de la valoración objetiva, las diferencias de género en el cumplimiento de las recomendaciones de actividad física fueron mayores de lo esperado. La teoría de la Autodeterminación surgió como un marco útil para identificar los factores motivacionales que pueden ser abordados en las intervenciones y programas de actividad física en el ámbito escolar para los jóvenes adolescentes

Subject-specific increases in serum S-100B distinguish sports-related concussion from sports-related exertion.

BACKGROUND: The on-field diagnosis of sports-related concussion (SRC) is complicated by the lack of an accurate and objective marker of brain injury. PURPOSE: To compare subject-specific changes in the astroglial protein, S100B, before and after SRC among collegiate and semi-professional contact sport athletes, and compare these changes to differences in S100B before and after non-contact exertion. STUDY DESIGN: Longitudinal cohort study. METHODS: From 2009-2011, we performed a prospective study of athletes from Munich, Germany, and Rochester, New York, USA. Serum S100B was measured in all SRC athletes at pre-season baseline, within 3 hours of injury, and at days 2, 3 and 7 post-SRC. Among a subset of athletes, S100B was measured after non-contact exertion but before injury. All samples were collected identically and analyzed using an automated electrochemiluminescent assay to quantify serum S100B levels. RESULTS: Forty-six athletes (30 Munich, 16 Rochester) underwent baseline testing. Thirty underwent additional post-exertion S100B testing. Twenty-two athletes (16 Rochester, 6 Munich) sustained a SRC, and 17 had S100B testing within 3 hours post-injury. The mean 3-hour post-SRC S100B was significantly higher than pre-season baseline (0.099±0.008 µg/L vs. 0.058±0.006 µg/L, p = 0.0002). Mean post-exertion S100B was not significantly different than the preseason baseline. S100B levels at post-injury days 2, 3 and 7 were significantly lower than the 3-hour level, and not different than baseline. Both the absolute change and proportional increase in S100B 3-hour post-injury were accurate discriminators of SRC from non-contact exertion without SRC (AUC 0.772 and 0.904, respectively). A 3-hour post-concussion S100B >0.122 µg/L and a proportional S100B increase of >45.9% over baseline were both 96.7% specific for SRC. CONCLUSIONS: Relative and absolute increases in serum S100B can accurately distinguish SRC from sports-related exertion, and may be a useful adjunct to the diagnosis of SRC.

Effects of early-life exposure to Western diet and wheel access on metabolic syndrome profiles in mice bred for high voluntary exercise.

Experimental studies manipulating diet and exercise have shown varying effects on metabolic syndrome components in both humans and rodents. To examine the potential interactive effects of diet, exercise and genetic background, we studied mice from four replicate lines bred (52 generations) for high voluntary wheel running (HR lines) and four unselected control lines (C). At weaning, animals were housed for 60 days with or without wheels and fed either a standard chow or Western diet (WD, 42% kcal from fat). Four serial (three juvenile and one adult) blood samples were taken to measure fasting total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides and glucose. Western diet was obesogenic for all mice, even after accounting for the amount of wheel running and kilojoules consumed. Western diet significantly raised glucose as well as TC and HDL-C concentrations. At the level of individual variation (repeatability), there was a modest correlation (r = 0.3-0.5) of blood lipids over time, which was reduced with wheel access and/or WD. Neither genetic selection history nor wheel access had a statistically significant effect on blood lipids. However, HR and C mice had divergent ontogenetic trajectories for body mass and caloric intake. HR mice also had lower adiposity, an effect that was dependent on wheel access. The environmental factors of diet and wheel access had pronounced effects on body mass, food consumption and fasting glucose concentrations, interacting with each other and/or with genetic strain. These data underscore the importance (and often unpredictable nature) of genotype-by-environment and environment-by-environment interactions when studying body weight regulation.