Gene networks in skeletal muscle following endurance exercise are coexpressed in blood neutrophils and linked with blood inflammation markers
It remains incompletely understood whether there is an association between the transcriptome profiles of skeletal muscle and blood leukocytes in response to exercise or other physiological stressors. We have previously analyzed the changes in the muscle and blood neutrophil transcriptome in eight trained men before and 3, 48, and 96 h after 2 h cycling and running. Because we collected muscle and blood in the same individuals and under the same conditions, we were able to directly compare gene expression between the muscle and blood neutrophils. Applying weighted gene coexpression network analysis (WGCNA) as an advanced ne...
Source: Journal of Applied Physiology - April 1, 2017 Category: Physiology Authors: Broadbent, J., Sampson, D., Sabapathy, S., Haseler, L. J., Wagner, K.-H., Bulmer, A. C., Peake, J. M., Neubauer, O. Tags: RESEARCH ARTICLE Source Type: research
Accelerated deflation promotes homogeneous airspace liquid distribution in the edematous lung
Edematous lungs contain regions with heterogeneous alveolar flooding. Liquid is trapped in flooded alveoli by a pressure barrier—higher liquid pressure at the border than in the center of flooded alveoli—that is proportional to surface tension, T. Stress is concentrated between aerated and flooded alveoli, to a degree proportional to T. Mechanical ventilation, by cyclically increasing T, injuriously exacerbates stress concentrations. Overcoming the pressure barrier to redistribute liquid more homogeneously between alveoli should reduce stress concentration prevalence and ventilation injury. In isolated rat lung...
Source: Journal of Applied Physiology - April 1, 2017 Category: Physiology Authors: Wu, Y., Nguyen, T. L., Perlman, C. E. Tags: RESEARCH ARTICLE Source Type: research
How does passive lengthening change the architecture of the human medial gastrocnemius muscle?
There are few comprehensive investigations of the changes in muscle architecture that accompany muscle contraction or change in muscle length in vivo. For this study, we measured changes in the three-dimensional architecture of the human medial gastrocnemius at the whole muscle level, the fascicle level and the fiber level using anatomical MRI and diffusion tensor imaging (DTI). Data were obtained from eight subjects under relaxed conditions at three muscle lengths. At the whole muscle level, a 5.1% increase in muscle belly length resulted in a reduction in both muscle width (mean change –2.5%) and depth (–4.8%...
Source: Journal of Applied Physiology - April 1, 2017 Category: Physiology Authors: Bolsterlee, B., DSouza, A., Gandevia, S. C., Herbert, R. D. Tags: RESEARCH ARTICLE Source Type: research
Could small-diameter muscle afferents be responsible for the ergogenic effect of limb ischemic preconditioning?
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - March 15, 2017 Category: Physiology Authors: Cruz, R. S. d. O., Pereira, K. L., Lisboa, F. D., Caputo, F. Tags: VIEWPOINT Source Type: research
Circulating microRNAs in acute and chronic exercise: more than mere biomarkers
MicroRNAs (miRNAs) are short, noncoding RNAs that influence biological processes by regulating gene expression after transcription. It was recently discovered that miRNAs are released into the circulation (ci-miRNAs) where they are highly stable and can act as intercellular messengers to affect physiological processes. This review provides a comprehensive summary of the studies to date that have investigated the effects of acute exercise and exercise training on ci-miRNAs in humans. Findings indicate that specific ci-miRNAs are altered in response to different protocols of acute and chronic exercise in both healthy and dis...
Source: Journal of Applied Physiology - March 15, 2017 Category: Physiology Authors: Sapp, R. M., Shill, D. D., Roth, S. M., Hagberg, J. M. Tags: REVIEW Source Type: research
A new method to evaluate macaque health using exhaled breath: A case study of M. tuberculosis in a BSL-3 setting
Breath is hypothesized to contain clinically relevant information, useful for the diagnosis and monitoring of disease, as well as understanding underlying pathogenesis. Nonhuman primates, such as the cynomolgus macaque, serve as an important model for the study of human disease, including over 70 different human infections. In this feasibility study, exhaled breath was successfully collected in less than 5 min under Biosafety Level 3 conditions from five anesthetized, intubated cynomolgus and rhesus macaques, before and after lung infection with M. tuberculosis. The breath was subsequently analyzed using comprehensive two-...
Source: Journal of Applied Physiology - March 15, 2017 Category: Physiology Authors: Mellors, T. R., Blanchet, L., Flynn, J. L., Tomko, J., OMalley, M., Scanga, C. A., Lin, P. L., Hill, J. E. Tags: INNOVATIVE METHODOLOGY Source Type: research
Heat induces interleukin-6 in skeletal muscle cells via TRPV1/PKC/CREB pathways
In this study we hypothesized that TRPV1 senses heat, transmits a signal into the nucleus, and produces IL-6. The purpose of the present study is to investigate the underlying mechanisms whereby skeletal muscle cells sense and respond to heat. When mouse myoblast cells were exposed to 37–42°C for 2 h, mRNA expression of IL-6 increased in a temperature-dependent manner. Heat also increased IL-6 secretion in myoblast cells. A fura 2 fluorescence dual-wavelength excitation method showed that heat increased intracellular calcium flux in a temperature-dependent manner. Intracellular calcium flux and IL-6 mRNA expressi...
Source: Journal of Applied Physiology - March 15, 2017 Category: Physiology Authors: Obi, S., Nakajima, T., Hasegawa, T., Kikuchi, H., Oguri, G., Takahashi, M., Nakamura, F., Yamasoba, T., Sakuma, M., Toyoda, S., Tei, C., Inoue, T. Tags: RESEARCH ARTICLE Source Type: research
Kinetics of circulating progenitor cell mobilization during submaximal exercise
Circulating progenitor cells (CPCs) are a heterogeneous population of stem/progenitor cells in peripheral blood that includes hematopoietic stem and progenitor cells (HSPCs and HSCs), endothelial progenitor cells (EPCs), and mesenchymal stem cells (MSCs) that are involved in tissue repair and adaptation. CPC mobilization during exercise remains uncharacterized in young adults. The purpose of this study was to investigate the kinetics of CPC mobilization during and after submaximal treadmill running and their relationship to mobilization factors. Seven men [age = 25.3 ± 2.4 yr, body mass index = 23.5 ± 1.0 kg/...
Source: Journal of Applied Physiology - March 15, 2017 Category: Physiology Authors: Niemiro, G. M., Parel, J., Beals, J., van Vliet, S., Paluska, S. A., Moore, D. R., Burd, N. A., De Lisio, M. Tags: RESEARCH ARTICLE Source Type: research
Alterations to mitochondrial fatty-acid use in skeletal muscle after chronic exposure to hypoxia depend on metabolic phenotype
We investigated the effects of chronic hypoxia on the maximal use of and sensitivity of mitochondria to different substrates in rat slow-oxidative (soleus, SOL) and fast-glycolytic (extensor digitorum longus, EDL) muscles. We studied mitochondrial respiration in situ in permeabilized myofibers, using pyruvate, octanoate, palmitoyl-carnitine (PC), or palmitoyl-coenzyme A (PCoA). The hypophagia induced by hypoxia may also alter metabolism. Therefore, we used a group of pair-fed rats (reproducing the same caloric restriction, as observed in hypoxic animals), in addition to the normoxic control fed ad libitum. The resting resp...
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Malgoyre, A., Chabert, C., Tonini, J., Koulmann, N., Bigard, X., Sanchez, H. Tags: RESEARCH ARTICLE Source Type: research
Adjustments with running speed reveal neuromuscular adaptations during landing associated with high mileage running training
This study is the first to demonstrate changes in neuromuscular conditioning with high mileage training, mainly characterized by lower thigh muscle activation after touch down, higher initial knee stiffness, and greater estimates of energy return, with adaptations being increasingly evident at faster running speeds. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Verheul, J., Clansey, A. C., Lake, M. J. Tags: RESEARCH ARTICLE Source Type: research
Influence of dietary nitrate supplementation on physiological and muscle metabolic adaptations to sprint interval training
We hypothesized that 4 wk of dietary nitrate supplementation would enhance exercise performance and muscle metabolic adaptations to sprint interval training (SIT). Thirty-six recreationally active subjects, matched on key variables at baseline, completed a series of exercise tests before and following a 4-wk period in which they were allocated to one of the following groups: 1) SIT and NO3–-depleted beetroot juice as a placebo (SIT+PL); 2) SIT and NO3–-rich beetroot juice (~13 mmol NO3–/day; SIT+BR); or 3) no training and NO3–-rich beetroot juice (NT+BR). During moderate-intensity exercise, pulmonar...
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Thompson, C., Wylie, L. J., Blackwell, J. R., Fulford, J., Black, M. I., Kelly, J., McDonagh, S. T. J., Carter, J., Bailey, S. J., Vanhatalo, A., Jones, A. M. Tags: RESEARCH ARTICLE Source Type: research
A single dose of histamine-receptor antagonists before downhill running alters markers of muscle damage and delayed-onset muscle soreness
In conclusion, histamine-receptor blockade reduced postexercise blood flow, had no effect on the pattern of inflammatory markers, increased serum creatine kinase concentrations, attenuated muscle strength loss, and reduced pain perception following muscle-damaging exercise.
NEW & NOTEWORTHY Histamine appears to be intimately involved with skeletal muscle during and following exercise. Blocking histamine’s actions during muscle-damaging exercise, via common over-the-counter antihistamines, resulted in increased serum creatine kinase, an indirect marker of muscle damage. Paradoxically, blocking histamine’s ac...
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Ely, M. R., Romero, S. A., Sieck, D. C., Mangum, J. E., Luttrell, M. J., Halliwill, J. R. Tags: RESEARCH ARTICLE Source Type: research
The impact of postexercise essential amino acid ingestion on the ubiquitin proteasome and autophagosomal-lysosomal systems in skeletal muscle of older men
Essential amino acid (EAA) ingestion enhances postexercise muscle protein synthesis, and, in particular, the anabolic response of older adults appears sensitive to the quantity of ingested leucine. The effect of leucine ingestion on muscle breakdown following resistance exercise (RE) is less understood. The purpose of this study was to identify the impact of postexercise leucine ingestion on the ubiquitin proteasome and autophagosomal-lysosomal systems following acute RE in older men. Subjects (72 ± 2 yr) performed RE and 1 h postexercise ingested 10 g of EAA containing a leucine quantity similar to quality protein ...
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Dickinson, J. M., Reidy, P. T., Gundermann, D. M., Borack, M. S., Walker, D. K., DLugos, A. C., Volpi, E., Rasmussen, B. B. Tags: RESEARCH ARTICLE Source Type: research
Oxidative phosphorylation: unique regulatory mechanism and role in metabolic homeostasis
Oxidative phosphorylation is the primary source of metabolic energy, in the form of ATP, in higher plants and animals, but its regulation in vivo is not well understood. A model has been developed for oxidative phosphorylation in vivo that predicts behavior patterns that are both distinctive and consistent with experimental measurements of metabolism in intact cells and tissues. A major regulatory parameter is the energy state ([ATP]/[ADP][Pi], where brackets denote concentration). Under physiological conditions, the [ATP] and [Pi] are ~100 times that of [ADP], and most of the change in energy state is through change in [A...
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Wilson, D. F. Tags: RESEARCH ARTICLE Source Type: research
Mast cell degranulation and de novo histamine formation contribute to sustained postexercise vasodilation in humans
In humans, acute aerobic exercise elicits a sustained postexercise vasodilation within previously active skeletal muscle. This response is dependent on activation of histamine H1 and H2 receptors, but the source of intramuscular histamine remains unclear. We tested the hypothesis that interstitial histamine in skeletal muscle would be increased with exercise and would be dependent on de novo formation via the inducible enzyme histidine decarboxylase and/or mast cell degranulation. Subjects performed 1 h of unilateral dynamic knee-extension exercise or sham (seated rest). We measured the interstitial histamine concentration...
Source: Journal of Applied Physiology - March 5, 2017 Category: Physiology Authors: Romero, S. A., McCord, J. L., Ely, M. R., Sieck, D. C., Buck, T. M., Luttrell, M. J., MacLean, D. A., Halliwill, J. R. Tags: RESEARCH ARTICLE Source Type: research
