Transcriptional and translational regulation of heat shock proteins in leukocytes of endurance runners

Microbial Symphony: Exploring the Role of the Gut in Osteoarthritis-Related Pain. A Narrative Review

One of the most common musculoskeletal disorders, osteoarthritis (OA), causes worldwide disability, morbidity, and poor quality of life by degenerating articular cartilage, modifying subchondral bone, and inflaming synovial membranes. OA pathogenesis pathways must be understood to generate new preventative and disease-modifying therapies. In recent years, it has been acknowledged that gut microbiota (GM) can significantly contribute to the development of OA. Dysbiosis of GM can disrupt the "symphony" between the host and the GM, leading to a host immunological response that activates the "gut-joint" axis, ultimately worsening OA. This narrative review summarizes research supporting the "gut-joint axis" hypothesis, focusing on the interactions between GM and the immune system in its two main components, innate and adaptive immunity. Furthermore, the pathophysiological sequence of events that link GM imbalance to OA and OA-related pain is broken down and further investigated. We also suggest that diet and prebiotics, probiotics, nutraceuticals, exercise, and fecal microbiota transplantation could improve OA management and represent a new potential therapeutic tool in the light of the scarce panorama of disease-modifying osteoarthritis drugs (DMOADs). Future research is needed to elucidate these complex interactions, prioritizing how a particular change in GM, i.e., a rise or a drop of a specific bacterial strain, correlates with a certain OA subset to pinpoint the associated signaling pathway that leads to OA.

The biphasic activity of autophagy and heat shock protein response in peripheral blood mononuclear cells following acute resistance exercise in resistance-trained males

PURPOSE

Autophagy and heat shock protein (HSP) response are proteostatic systems involved in the acute and adaptive responses to exercise. These systems may upregulate sequentially following cellular stress including acute exercise, however, currently few data exist in humans. This study investigated the autophagic and HSP responses to acute intense lower body resistance exercise in peripheral blood mononuclear cells (PBMCs) with and without branched-chain amino acids (BCAA) supplementation.

METHODS

Twenty resistance-trained males (22.3 ± 1.5 yr; 175.4 ± .7 cm; 86.4 ± 15.6 kg) performed a bout of intense lower body resistance exercise and markers of autophagy and HSP70 were measured immediately post- (IPE) and 2, 4, 24, 48, and 72 h post-exercise. Prior to resistance exercise, 10 subjects were randomly assigned to BCAA supplementation of 0.22 g/kg/d for 5 days pre-exercise and up to 72 h following exercise while the other 10 subjects consumed a placebo (PLCB).

RESULTS

There were no difference in autophagy markers or HSP70 expression between BCAA and PLCB groups. LC3II protein expression was significantly lower 2 and 4 h post-exercise compared to pre-exercise. LC3II: I ratio was not different at any time point compared to pre-exercise. Protein expression of p62 was lower IPE, 2, and 4 h post-exercise and elevated 24 h post-exercise. HSP70 expression was elevated 48 and 72 h post-exercise.

CONCLUSIONS

Autophagy and HSP70 are upregulated in PBMCs following intense resistance exercise with autophagy increasing initially post-exercise and HSP response in the latter period. Moreover, BCAA supplementation did not affect this response.

Sitting Less, Recovering Faster: Investigating the Relationship between Daily Sitting Time and Muscle Recovery following Intense Exercise: A Pilot Study

(1) There is growing concern surrounding the adverse effects of prolonged sitting on health, yet its impact on post-exercise recovery remains relatively unexplored. This study aimed to better understand the potential influence of habitual prolonged sitting on recovery time and the unfavorable impact prolonged sitting may have on time to recovery, as assessed by muscle damage and inflammatory markers and an isokinetic dynamometer. (2) Nine college-age men (mean age ± SD = 22.1 ± 3.1 years, body mass = 80.9 ± 15.7 kg, height = 171 ± 9.0 cm, Body Mass Index (BMI) = 27.6 ± 4.9 kg·m2) participated in an exhaustive exercise protocol. Creatine Kinase (CK), Myoglobin (Mb), C-Reactive Protein (CRP), White Blood Cell Count (WBC), Peak Torque (PT), and muscle soreness were measured at baseline and 0, 24, 48, and 72 h post-exercise. Dietary and exercise logs were maintained during the 5-day testing procedure. (3) No significant differences were observed in muscle damage markers (CK [p = 0.068] and Mb [p = 0.128]), inflammatory markers (CRP [p = 0.814] and WBC [p = 0.140]), or PT [p = 0.255]) at any time point. However, a significant positive correlation was found between daily sitting time and the percent increase in CK concentration from 0 h to 72 h (r = 0.738, p = 0.023). Strong correlations were also noted between prolonged sitting and percent change in Mb concentration at 48 h (r = 0.71, p = 0.033) and 72 h (r = 0.889, p = 0.001). There was a significant two-way interaction for time × velocity (p = 0.043) for PT with a simple main effect for time at 60°·s-1 (p = 0.038). No significant associations were detected between daily carbohydrate or protein intake and recovery markers (p > 0.05). (4) The findings suggest minimizing daily sitting time may expedite and potentially aid muscle recovery after an intense exercise bout, although further research is warranted to validate these findings.

A Bibliometric Analysis on the Research Trend of Exercise and the Gut Microbiome

This article aims to provide an overview of research hotspots and trends in exercise and the gut microbiome, a field which has recently gained increasing attention. The relevant publications on exercise and the gut microbiome were identified from the Web of Science Core Collection database. The publication types were limited to articles and reviews. VOSviewer 1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, the Netherlands) and the R package "bibliometrix" (R Foundation: Vienna, Austria) were used to conduct a bibliometric analysis. A total of 327 eligible publications were eventually identified, including 245 original articles and 82 reviews. A time trend analysis showed that the number of publications rapidly increased after 2014. The leading countries/regions in this field were the USA, China, and Europe. Most of the active institutions were from Europe and the USA. Keyword analysis showed that the relationship between disease, the gut microbiome, and exercise occurs throughout the development of this field of research. The interactions between the gut microbiota, exercise, status of the host's internal environment, and probiotics, are important facets as well. The research topic evolution presents a trend of multidisciplinary and multi-perspective comprehensive analysis. Exercise might become an effective intervention for disease treatment by regulating the gut microbiome. The innovation of exercise-centered lifestyle intervention therapy may become a significant trend in the future.

Exercise-induced changes to the human gut microbiota and implications for colorectal cancer: a narrative review

Physical activity is associated with reduced risks of colorectal cancer (CRC) incidence, recurrence and mortality. While these findings are consistent, the mechanism/s underlying this association remain unclear. Growing evidence supports the many ways in which differing characteristics of the gut microbiota can be tumourigenic or protective against CRC. CRC is characterised by significant dysbiosis including reduced short chain fatty acid-producing bacteria. Recent findings suggest that exercise can modify the gut microbiota, and these changes are inverse to the changes seen with CRC; however, this exercise-microbiota interaction is currently understudied in CRC. This review summarises parallel areas of research that are rapidly developing: The exercise-gut microbiota research and cancer-gut microbiota research and highlights the salient similarities. Preliminary evidence suggests that these areas are linked, with exercise mediating changes that promote the antitumorigenic characteristics of the gut microbiota. Future mechanistic and population-specific studies are warranted to confirm the physiological mechanism/s by which exercise changes the gut microbiota, and the influence of the exercise-gut interaction on cancer specific outcomes in CRC.

Changes in Cytokines Concentration Following Long-Distance Running: A Systematic Review and Meta-Analysis

Long-distance running is an exhausting effort for the whole organism. Prolonged aerobic exercise induces changes in inflammatory markers. However, predicting muscle damage in response has limitations in terms of selecting biomarkers used to measure inflammatory status. The present study conducts a systematic review and meta-analysis of articles focusing in ultra-marathon, marathon, and half-marathon and levels of cytokines. The search was conducted in PubMed, Web of Science, and Scopus databases, resulting in the inclusion of 76 articles. IL-6 was highlighted, evaluated in 62 studies and show increase in the standard mean difference (SMD): half-marathon (SMD −1.36; IC 95%: −1.82, −0.89, Ch²:0.58; tau²:0.00; p < 0.0001), marathon (SMD −6.81; IC 95%: −9.26, −4.37; Ch²:481.37 tau²:11.88; p < 0.0001) and ultra-marathon (SMD −8.00 IC 95%: −10.47, −5.53; Ch²:328.40; tau²:14.19; p < 0.0001). In contrast meta-regression analysis did not show relationship to the running distance (p = 0.864). The meta-analysis evidenced increase in the concentration of IL-1ra (p < 0.0001), IL-1B (p < 0.0001), IL-8 (p < 0.0001), IL-10 (p < 0.0001) and TNF-α (p < 0.0001). Reduction in IL-2 (p < 0.0001) and INF-y (p < 0.03) and no change in the IL-4 (p < 0.56). The number of studies evaluating the effect of adipokines was limited, however Leptin and Resistin were recurrent. The effects of an acute bout of prolonged aerobic exercise will protect against chronic systemic inflammation. The time to return to baseline values showed a substantial and dose-dependent relationship with run volume. The concentration of IL-6 was robustly studied and the marathon running was the most explored. Network of endocrine interactions in which circulating factors, released in extreme exercises, interplay through inter-organ crosstalk and physiologic changes were expressed. The running volume variability was able to modulate compounds that play a fundamental role in the maintenance of homeostasis and cell signaling.

The Association between Gut Microbiota and Osteoarthritis: Does the Disease Begin in the Gut?

Some say that all diseases begin in the gut. Interestingly, this concept is actually quite old, since it is attributed to the Ancient Greek physician Hippocrates, who proposed the hypothesis nearly 2500 years ago. The continuous breakthroughs in modern medicine have transformed our classic understanding of the gastrointestinal tract (GIT) and human health. Although the gut microbiota (GMB) has proven to be a core component of human health under standard metabolic conditions, there is now also a strong link connecting the composition and function of the GMB to the development of numerous diseases, especially the ones of musculoskeletal nature. The symbiotic microbes that reside in the gastrointestinal tract are very sensitive to biochemical stimuli and may respond in many different ways depending on the nature of these biological signals. Certain variables such as nutrition and physical modulation can either enhance or disrupt the equilibrium between the various species of gut microbes. In fact, fat-rich diets can cause dysbiosis, which decreases the number of protective bacteria and compromises the integrity of the epithelial barrier in the GIT. Overgrowth of pathogenic microbes then release higher quantities of toxic metabolites into the circulatory system, especially the pro-inflammatory cytokines detected in osteoarthritis (OA), thereby promoting inflammation and the initiation of many disease processes throughout the body. Although many studies link OA with GMB perturbations, further research is still needed.

Systemic Response of Antioxidants, Heat Shock Proteins, and Inflammatory Biomarkers to Short-Lasting Exercise Training in Healthy Male Subjects

Regular physical activity can enhance immune function and effectively prevents the spread of the cytokine response, thus reducing systemic low-grade inflammation and improving various immune markers. Moreover, regular exercise maintains redox homeostasis in skeletal muscle and other tissues, including immune cells, but the interconnection between the anti-inflammatory effects of exercise with the redox status of immune cells is still poorly understood. With the aim to verify the overall beneficial effect of regular training on the immune system, we have examined the acute and short-term effect of a 5-day exercise program on the modulation of protein and lipid oxidation, antioxidants (i.e., superoxide dismutase-1 (SOD1) and superoxide dismutase-2 (SOD2), glutathione peroxide 1 (GPx1), thioredoxin reductase-1 (TrxR1), and catalase (CAT)), and heat shock protein expression (i.e., heat shock protein-70 (HSP70) and heat shock protein-27 (HSP27)), at both mRNA and protein levels, as well as the activation of the nuclear factor kappa light chain enhancer of activated B cells (NFκB) in peripheral blood mononuclear cells (PBMCs). Moreover, plasmatic markers of oxidative stress, inflammation, and stress response (i.e., protein carbonyl content, interleukin-6 (IL6), interleukin-8 (IL8), interleukin-10 (IL10), interleukin-17E (IL17E), interleukin-17F (IL17F), interleukin-21 (IL21), interleukin-22 (IL22), and interleukin-23 (IL23)) were analyzed in active untrained young adult subjects. Even in the absence of an increased amount of protein or lipid oxidation, we confirmed a PBMC upregulation of SOD1 (1.26 ± 0.07 fold change, p < 0.05), HSP70 (1.59 ± 0.28 fold change, p < 0.05), and HSP27 gene expression (1.49 ± 0.09 fold change, p < 0.05) after 3 hours from the first bout of exercise, followed by an increase in proteins' amount at 24 hours (SOD1, 1.80 ± 0.34 fold change; HSP70, 3.40 ± 0.58 fold change; and HSP27, 1.81 ± 0.20 fold change, p < 0.05) and return to basal levels after the 5 days of aerobic training. Indeed, the posttraining basal levels of oxidized molecules in plasma and PBMCs were statistically lower than the pretraining levels (carbonyl content, 0.50 ± 0.05 fold change, p < 0.01), paralleled by a lower expression of SOD2, Gpx1, and TrxR1, at mRNA (SOD2, 0.63 ± 0.06; GPx1, 0.69 ± 0.07; and TrxR1, 0.69 ± 0.12 fold change, p < 0.05) and protein (TrxR1, 0.49 ± 0.11 fold change, p < 0.05) levels. These results verified the existence of an early phase of redox adaptation to physical exercise already achievable after 5 days of moderate, regular aerobic training. More interestingly, this phenomenon was paralleled by the degree of NFκB activation in PBMCs and the decrease of plasmatic proinflammatory cytokines IL8, IL21, and IL22 in the posttraining period, suggesting an interconnected, short-term efficacy of aerobic exercise towards systemic oxidative stress and inflammation.

Gut microbiome functionality might be associated with exercise tolerance and recurrence of resected early-stage lung cancer patients

Impaired exercise tolerance and lung function is a marker for increased mortality in lung cancer patients undergoing lung resection surgery. Recent data suggest that the gut-lung axis regulates systemic metabolic and immune functions, and microbiota might alter exercise tolerance. Here, we aimed to evaluate the associations between gut microbiota and outcomes in lung cancer patients who underwent lung resection surgery. We analysed stool samples, from 15 early-stage lung cancer patients, collected before and after surgical resection using shotgun metagenomic and Internal Transcribed Spacer (ITS) sequencing. We analysed microbiome and mycobiome associations with post-surgery lung function and cardiopulmonary exercise testing (CPET) to assess the maximum level of work achieved. There was a significant difference, between pre- and post-surgical resection samples, in microbial community functional profiles and several species from Alistipes and Bacteroides genus, associated with the production of SCFAs, increased significantly in abundance. Interestingly, an increase in VO2 coincides with an increase in certain species and the "GABA shunt" pathway, suggesting that treatment outcome might improve by enriching butyrate-producing species. Here, we revealed associations between specific gut bacteria, fungi, and their metabolic pathways with the recovery of lung function and exercise capacity.

The effect of vitamin D supplementation on the muscle damage after eccentric exercise in young men: a randomized, control trial

Background

Vitamin D contributes to the optimal functioning of muscles. This study was designed to determine the modulating effect of vitamin D supplementation on the degree of muscle cell damage caused by eccentric exercise in young men.

Methods

60 male volunteers (20–24 years old) taking part in this study were divided in two groups - with suboptimal (S) and optimal (O;) 25(OH)D plasma levels. These groups were randomly subdivided into groups with vitamin D supplementation (experimental: SE and OE) and controls (SC and OC). Before the supplementation (Test I) and after 3 months (Test II), participants were subjected to two rounds of eccentric exercise tests on a declined treadmill (running speed corresponded 60% VO2peak determined in each subject in incremental exercise test). During each test, blood samples used for determination of 25(OH)D, Il-1β, myoglobin (Mb) levels and CK, LDH activity were taken at three timepoints: before the test, 1 h and 24 h after it ended.

After distribution normality testing (Saphiro-Wilk test), statistical analyses were performed. Non-parametric: Kruskal-Wallis test and the Wilcoxon test were applied, and the Dunn-Bonferroni test as a post-hoc test.

Results

In all groups, after 3 months, higher concentrations of 25(OH)D were indicated (SE p = 0.005; SC p = 0.018; OE p = 0.018; OC p = 0.028). SE and SC groups showed higher baseline concentrations of Il-1β and significantly higher concentrations of this interleukin after 1 h compared to groups with an optimal 25(OH)D level. After supplementation, the SE group reacted with a similar jump in concentration of Il-1β as the OC and OE groups. The change after 1 h after exercise in Test II was significantly different from that from Test I (p = 0.047) in SE group. Lower Mb concentrations indicated 1 h after exercise in Test II for SC and SE groups were indicated. CK activity did not differentiate the studied groups. Plasma calcium and phosphate disorders were also not indicated.

Conclusions

The study has shown that vitamin D doses determined from the plasma concentration of 25(OH)D of individuals to match their specific needs can significantly reduce muscle cell damage induced by eccentric exercise.

Role of heat shock proteins 70/90 in exercise physiology and exercise immunology and their diagnostic potential in sports

Heat shock proteins (HSPs) are molecular chaperones facilitating the unfolding or folding of secondary structures of proteins, their client proteins, in cellular stress situations. Various internal and external physiological and mechanical stress factors induce a homeostatic imbalance, followed by an increased expression of HSP70 and HSP90. Exercise is a stress factor, too, and its cumulative physiological perturbation manifests at a cellular level by threatening the protein homeostasis of various cell types. Consequently, an increase of HSP70/90 was described in plasma and mononuclear cells and various organs and tissues, such as muscle, liver, cardiac tissue, and brain, after an acute bout of exercise. The specific response of HSP70/90 seems to be strongly related to the modality of exercise, with several dependent factors such as duration, intensity, exercise type, subjects’ training status, and environmental factors, e.g., temperature. It is suggested that HSP70/90 play a major role in immune regulation and cell protection during exercise and in the efficiency of regeneration and reparation processes. During long-term training, HSP70/90 are involved in preconditioning and adaptation processes that might also be important for disease prevention and therapy. With regard to their highly sensitive and individual response to specific exercise and training modalities, this review discusses whether and how HSP70 and HSP90 can be applied as biomarkers for monitoring exercise and training.

Exercise-induced bronchoconstriction, temperature regulation and the role of heat shock proteins in non-asthmatic recreational marathon and half-marathon runners

Exercise is the most common trigger of bronchospasm. Heat shock protein (HSP) expression was linked to asthmatic patients. The prevalence and pathophysiology of exercise-induced bronchoconstriction (EIB) in non-professional non-asthmatic runners is unknown. We sought to investigate the frequency of EIB and cytokine changes in non-professional non-asthmatic marathon and half marathoners with and without EIB. Testing was performed before the marathon (baseline), immediately post-marathon at the finish area (peak), and 2–7 days after the marathon (recovery): immunosorbent assays for measurement of HSP70, blood count analysis, spirometry and temperature measurements. We experienced a decline in FEV1 of ≥10% in 35.29% of marathon and 22.22% of half marathon runners. Runners with EIB had significantly higher HSP70 serum concentrations at baseline than those without EIB (987.4 ± 1486.7 vs. 655.6 ± 1073.9; p = 0.014). Marathoners with EIB had significantly increased WBC before participating in the competition (7.4 ± 1.7 vs. 6.0 ± 1.5; p = 0.021). After recovery we found increased HSP70 serum concentrations in marathoners with EIB compared to those without (2539.2 ± 1692.5 vs. 1237.2 ± 835.2; p = 0.032), WBC (7.6 ± 1.8 vs. 6.4 ± 1.6; p = 0.048) and PLT (273.0 ± 43.0 vs 237.2 ± 48.3; p = 0.040). At all measured skin sites skin temperatures in runners were significantly lower immediately after participating in the competition when compared to temperature before the race (skin temperature baseline vs. peak: abdominal: 33.1 ± 0.2 vs. 30.0 ± 0.4; p < 0.001; upper arm: 31.6 ± 0.2 vs. 29.4 ± 0.3; p < 0.001; upper leg: 30.7 ± 0.3 vs. 29.4 ± 0.2; p = 0.014; lower leg: 30.6 ± 1.0 vs. 30.2 ± 1.5; p = 0.007). We found a higher than expected number of non-professional athletes with EIB. HSP70 serum concentrations and elevated WBC could indicate a predisposition to EIB.

Epithelial to Mesenchymal transition, eIF2α phosphorylation and Hsp70 expression enable greater tolerance in A549 cells to TiO2 over ZnO nanoparticles

Type II alveolar cells are highly robust in nature, yet susceptible to aerosolized nanoparticles (NPs). Dysfunction in these specialized cells, can often lead to emphysema, edema, and pulmonary inflammation. Long-time exposure can also lead to dangerous epigenetic modifications and cancer. Among the manufactured nanomaterials, metal oxide nanoparticles are widely encountered owing to their wide range of applications. Scores of published literatures affirm ZnO NPs are more toxic to human alveolar cells than TiO₂. However, signalling cascades deducing differences in human alveolar responses to their exposure is not well documented. With A549 cells, we have demonstrated that epithelial to mesenchymal transition and an increased duration of phosphorylation of eIF2α are crucial mechanisms routing better tolerance to TiO₂ NP treatment over exposure to ZnO. The increased migratory capacity may help cells escape away from the zone of stress. Further, expression of chaperone such as Hsp70 is also enhanced during the same dose-time investigations. This is the first report of its kind. These novel findings could be successfully developed in the future to design relief strategies to alleviate metal oxide nanoparticle mediated stress.

Acute long-distance trail running increases serum IL-6, IL-15, and Hsp72 levels

Interleukin-6 (IL-6), IL-15, and heat shock protein 72 (Hsp72) are molecules that have significant metabolic effects on glucose and fat metabolism and a cell's stress response. The aim of this study is to determine serum levels of these molecules in runners after a long-distance trail run. Serum IL-15 levels after such endurance events have not been investigated yet. Blood samples were collected from 37 athletes (11 female, 26 male) before and after a 35-km trail run, with a total climb of 940 m. Serum was obtained from the samples, and IL-6, IL-15, and Hsp72 levels were measured from using the sandwich ELISA method. The athletes completed the race in 308.3 ± 37.4 min on average. After the race, the mean serum IL-6, IL-15, and Hsp72 concentrations increased 13.2-fold, 2.22-fold, and 1.6-fold, respectively (p < 0.001, p < 0.001, and p = 0.039, respectively). This is the first study to demonstrate the increase in serum IL-15 levels following an acute endurance exercise. In addition to IL-15, we report that IL-6 and soluble Hsp72 levels also increased significantly following a 35-km trail run. Since these molecules are involved in regulating glucose and fat metabolism, significant increases of IL-6, IL-15, and soluble Hsp72 may have health benefits that may be associated with long-distance trail runs, which are becoming more popular worldwide.

Redox Aspects of Chaperones in Cardiac Function

Molecular chaperones are stress proteins that allow the correct folding or unfolding as well as the assembly or disassembly of macromolecular cellular components. Changes in expression and post-translational modifications of chaperones have been linked to a number of age- and stress-related diseases including cancer, neurodegeneration, and cardiovascular diseases. Redox sensible post-translational modifications, such as S-nitrosylation, glutathionylation and phosphorylation of chaperone proteins have been reported. Redox-dependent regulation of chaperones is likely to be a phenomenon involved in metabolic processes and may represent an adaptive response to several stress conditions, especially within mitochondria, where it impacts cellular bioenergetics. These post-translational modifications might underlie the mechanisms leading to cardioprotection by conditioning maneuvers as well as to ischemia/reperfusion injury. In this review, we discuss this topic and focus on two important aspects of redox-regulated chaperones, namely redox regulation of mitochondrial chaperone function and cardiac protection against ischemia/reperfusion injury.

Effects of age and exercise on inflammatory cytokines, HSP70 and HSP90 gene expression and protein content in Standardbred horses

We hypothesised that the cortisol response to acute exercise, markers of oxidative stress, expression of inflammatory cytokines, heat shock protein (HSP)70 and HSP90 expression in whole blood and skeletal muscle, and HSP70 and HSP90 protein concentrations in skeletal muscle are altered by age and in response to acute submaximal exercise in horses. Young (n=6; 5.5±2.8 year) and aged (n=6; 22.6±2.25 year) unconditioned Standardbred mares underwent an acute submaximal exercise test. Blood samples were collected and analysed for plasma cortisol and malondialdehyde (MDA) concentrations, and for cytokine and HSP gene expression pre- and post-exercise. Gluteus medius biopsies were obtained for analysis of cytokine and HSP gene expression pre- and at 0, 4, 24 and 48 h post-exercise. Data were analysed for main effects using a two-way ANOVA for repeated measures. Post-hoc comparisons of means were conducted using Student-Neuman-Keuls for pair-wise multiple comparisons where appropriate. Acute submaximal exercise increased plasma cortisol concentration in both young and aged mares, and the duration of the post-exercise rise in cortisol was altered in aged horses. Plasma MDA concentration and expression of tumour necrosis factor-α (TNF-α) and interleukin (IL)-6 were unchanged in blood and muscle. Exercise increased IL-1β expression in whole blood of young and aged mares, with young mares having greater exercise-induced expression at 2 (P<0.001) and 4 (P=0.019) h post-exercise. Both young and aged horses had increased HSP70 expression in whole blood following acute exercise, with young horses exhibiting 3-fold greater HSP70 expression than aged mares at 2 h post-exercise. HSP90 expression in whole blood following exercise was increased only in young horses. Both young and aged horses had increased HSP90 expression in skeletal muscle following exercise, but there was no difference due to age. However, the timing of HSP70 expression was different between young and aged horses. The age-related changes in cortisol and IL-1β expression following acute submaximal exercise can have implications for energy homeostasis and the adaption to such disturbances at a cellular and whole animal level. Quantification of HSP expression in whole blood may be a useful biomarker, with implications for cellular adaptation and survival in aged horses.

Pregnancy History Influences the Level of Autophagy in Peripheral Blood Mononuclear Cells From Pregnant Women

OBJECTIVE

Maternal immune responses are altered during pregnancy and differ between nulliparous and multiparous women. The influence of a prior gestation on autophagy in peripheral blood mononuclear cells (PBMCs) from pregnant women has not been determined and is the subject of this investigation.

METHODS

Peripheral blood mononuclear cells were isolated from 212 pregnant women and immediately lysed in the presence of protease inhibitors, and the extent of autophagy was determined by quantitation of the concentration of p62 (sequestosome-1) in the lysates by enzyme-linked immunosorbent assay (ELISA). In PBMCs, the p62 level is inversely related to the extent of autophagy. The level of the stress-inducible 70-kDa heat shock protein (hsp70), an inhibitor of autophagy, was also measured in the lysates by ELISA. Data were analyzed by the Spearman rank correlation, Mann-Whitney U test, or Kruskal-Wallis test, as appropriate.

RESULTS

The p62 concentration in PBMCs increased (autophagy decreased) with the number of previous live ( P = .0322), preterm ( P = .0143), or term ( P = .0418) deliveries. The p62 level was lower (autophagy higher) in women with a prior spontaneous pregnancy loss but no deliveries as compared to women with their first conception ( P = .0087). The intracellular hsp70 concentration correlated with the p62 level ( P < .0001).

CONCLUSION

Multiparity is associated with a reduced level of autophagy in PBMCs. Dysregulated autophagy might be one mechanism leading to spontaneous abortion in nulliparous women.

Ursolic acid supplementation decreases markers of skeletal muscle damage during resistance training in resistance-trained men: a pilot study

Ursolic acid (UA) supplementation was previously shown to improve skeletal muscle function in resistance-trained men. This study aimed to determine, using the same experimental paradigm, whether UA also has beneficial effects on exercise-induced skeletal muscle damage markers including the levels of cortisol, B-type natriuretic peptide (BNP), myoglobin, creatine kinase (CK), creatine kinase-myocardial band (CK-MB), and lactate dehydrogenase (LDH) in resistance-trained men. Sixteen healthy participants were randomly assigned to resistance training (RT) or RT+UA groups (n=8 per group). Participants were trained according to the RT program (60~80% of 1 repetition, 6 times/week), and the UA group was additionally given UA supplementation (450 mg/day) for 8 weeks. Blood samples were obtained before and after intervention, and cortisol, BNP, myoglobin, CK, CK-MB, and LDH levels were analyzed. Subjects who underwent RT alone showed no significant change in body composition and markers of skeletal muscle damage, whereas RT+UA group showed slightly decreased body weight and body fat percentage and slightly increased lean body mass, but without statistical significance. In addition, UA supplementation significantly decreased the BNP, CK, CK-MB, and LDH levels (p<0.05). In conclusion, UA supplementation alleviates increased skeletal muscle damage markers after RT. This finding provides evidence for a potential new therapy for resistance-trained men.

Acute and Chronic Effects of Endurance Running on Inflammatory Markers: A Systematic Review

In order to understand the effect of endurance running on inflammation, it is necessary to quantify the extent to which acute and chronic running affects inflammatory mediators. The aim of this study was to summarize the literature on the effects of endurance running on inflammation mediators. Electronic searches were conducted on PubMED and Science Direct with no limits of date and language of publication. Randomized controlled trials (RCTs) and non-randomized controlled trials (NRCTs) investigating the acute and chronic effects of running on inflammation markers in runners were reviewed by two researchers for eligibility. The modified Downs and Black checklist for the assesssments of the methodological quality of studies was subsequently used. Fifty-one studies were finally included. There were no studies with elite athletes. Only two studies were chronic interventions. Results revealed that acute and chronic endurance running may affect anti- and pro-inflammatory markers but methodological differences between studies do not allow comparisons or generalization of the results. The information provided in this systematic review would help practitioners for better designing further studies while providing reference values for a better understanding of inflammatory responses after different running events. Further longitudinal studies are needed to identify the influence of training load parameters on inflammatory markers in runners of different levels and training background.

Affected pathways and transcriptional regulators in gene expression response to an ultra-marathon trail: Global and independent activity approaches

Gene expression (GE) analyses on blood samples from marathon and half-marathon runners have reported significant impacts on the immune and inflammatory systems. An ultra-marathon trail (UMT) represents a greater effort due to its more testing conditions. For the first time, we report the genome-wide GE profiling in a group of 16 runners participating in an 82 km UMT competition. We quantified their differential GE profile before and after the race using HuGene2.0st microarrays (Affymetrix Inc., California, US). The results obtained were decomposed by means of an independent component analysis (ICA) targeting independent expression modes. We observed significant differences in the expression levels of 5,084 protein coding genes resulting in an overrepresentation of 14% of the human biological pathways from the Kyoto Encyclopedia of Genes and Genomes database. These were mainly clustered on terms related with protein synthesis repression, altered immune system and infectious diseases related mechanisms. In a second analysis, 27 out of the 196 transcriptional regulators (TRs) included in the Open Regulatory Annotation database were overrepresented. Among these TRs, we identified transcription factors from the hypoxia-inducible factors (HIF) family EPAS1 (p< 0.01) and HIF1A (p<0.001), and others jointly described in the gluconeogenesis program such as HNF4 (p< 0.001), EGR1 (p<0.001), CEBPA (p< 0.001) and a highly specific TR, YY1 (p<0.01). The five independent components, obtained from ICA, further revealed a down-regulation of 10 genes distributed in the complex I, III and V from the electron transport chain. This mitochondrial activity reduction is compatible with HIF-1 system activation. The vascular endothelial growth factor (VEGF) pathway, known to be regulated by HIF, also emerged (p<0.05). Additionally, and related to the brain rewarding circuit, the endocannabinoid signalling pathway was overrepresented (p<0.05).

Hypoxic Air Inhalation and Ischemia Interventions Both Elicit Preconditioning Which Attenuate Subsequent Cellular Stress In vivo Following Blood Flow Occlusion and Reperfusion

Ischemic preconditioning (IPC) is valid technique which elicits reductions in femoral blood flow occlusion mediated reperfusion stress (oxidative stress, Hsp gene transcripts) within the systemic blood circulation and/or skeletal muscle. It is unknown whether systemic hypoxia, evoked by hypoxic preconditioning (HPC) has efficacy in priming the heat shock protein (Hsp) system thus reducing reperfusion stress following blood flow occlusion, in the same manner as IPC. The comparison between IPC and HPC being relevant as a preconditioning strategy prior to orthopedic surgery. In an independent group design, 18 healthy men were exposed to 40 min of (1) passive whole-body HPC (FiO₂ = 0.143; no ischemia. N = 6), (2) IPC (FiO₂ = 0.209; four bouts of 5 min ischemia and 5 min reperfusion. n = 6), or (3) rest (FiO₂ = 0.209; no ischemia. n = 6). The interventions were administered 1 h prior to 30 min of tourniquet derived femoral blood flow occlusion and were followed by 2 h subsequent reperfusion. Systemic blood samples were taken pre- and post-intervention. Systemic blood and gastrocnemius skeletal muscle samples were obtained pre-, 15 min post- (15PoT) and 120 min (120PoT) post-tourniquet deflation. To determine the cellular stress response gastrocnemius and leukocyte Hsp72 mRNA and Hsp32 mRNA gene transcripts were determined by RT-qPCR. The plasma oxidative stress response (protein carbonyl, reduced glutathione/oxidized glutathione ratio) was measured utilizing commercially available kits. In comparison to control, at 15PoT a significant difference in gastrocnemius Hsp72 mRNA was seen in HPC (−1.93-fold; p = 0.007) and IPC (−1.97-fold; p = 0.006). No significant differences were observed in gastrocnemius Hsp32 and Hsp72 mRNA, leukocyte Hsp72 and Hsp32 mRNA, or oxidative stress markers (p > 0.05) between HPC and IPC. HPC provided near identical amelioration of blood flow occlusion mediated gastrocnemius stress response (Hsp72 mRNA), compared to an established IPC protocol. This was seen independent of changes in systemic oxidative stress, which likely explains the absence of change in Hsp32 mRNA transcripts within leukocytes and the gastrocnemius. Both the established IPC and novel HPC interventions facilitate a priming of the skeletal muscle, but not leukocyte, Hsp system prior to femoral blood flow occlusion. This response demonstrates a localized tissue specific adaptation which may ameliorate reperfusion stress.

The Hsp72 and Hsp90α mRNA Responses to Hot Downhill Running Are Reduced Following a Prior Bout of Hot Downhill Running, and Occur Concurrently within Leukocytes and the Vastus Lateralis

The leukocyte heat shock response (HSR) is used to determine individual's thermotolerance. The HSR and thermotolerance are enhanced following interventions such as preconditioning and/or acclimation/acclimatization. However, it is unclear whether the leukocyte HSR is an appropriate surrogate for the HSR in other tissues implicated within the pathophysiology of exertional heat illnesses (e.g., skeletal muscle), and whether an acute preconditioning strategy (e.g., downhill running) can improve subsequent thermotolerance. Physically active, non-heat acclimated participants were split into two groups to investigate the benefits of hot downhill running as preconditioning strategy. A hot preconditioning group (HPC; n = 6) completed two trials (HPC1_HOTDOWN and HPC2_HOTDOWN) of 30 min running at lactate threshold (LT) on -10% gradient in 30°C and 50% relative humidity (RH) separated by 7 d. A temperate preconditioning group (TPC; n = 5) completed 30 min running at LT on a -1% gradient in 20°C and 50% (TPC1_TEMPFLAT) and 7 d later completed 30 min running at LT on -10% gradient in 30°C and 50% RH (TPC2_HOTDOWN). Venous blood samples and muscle biopsies (vastus lateralis; VL) were obtained before, immediately after, 3, 24, and 48 h after each trial. Leukocyte and VL Hsp72, Hsp90α, and Grp78 mRNA relative expression was determined via RT-QPCR. Attenuated leukocyte and VL Hsp72 (2.8 to 1.8 fold and 5.9 to 2.4 fold; p < 0.05) and Hsp90α mRNA (2.9 to 2.4 fold and 5.2 to 2.4 fold; p < 0.05) responses accompanied reductions (p < 0.05) in physiological strain [exercising rectal temperature (-0.3°C) and perceived muscle soreness (~ -14%)] during HPC2_HOTDOWN compared to HPC1_HOTDOWN (i.e., a preconditioning effect). Both VL and leukocyte Hsp72 and Hsp90α mRNA increased (p < 0.05) simultaneously following downhill runs and demonstrated a strong relationship (p < 0.01) of similar magnitudes with one another. Hot downhill running is an effective preconditioning strategy which ameliorates physiological strain, soreness and Hsp72 and Hsp90α mRNA responses to a subsequent bout. Leukocyte and VL analyses are appropriate tissues to infer the extent to which the HSR has been augmented.

Exosomes Mediate the Beneficial Effects of Exercise

It is known that moderate exercise can prevent the development of cardiovascular diseases, but the exact molecular mechanisms mediating cardioprotective effect of exercise remain unknown. Emerging evidence suggests that exercise has great impact on the biogenesis of exosomes, which have been found in both interstitial fluid and circulation, and play important roles in cellular communication. Exosomes carry functional molecules such as mRNAs, microRNA, and specific proteins, which can be used in the early diagnosis and targeted therapy of a variety of diseases. Our review focus on the current knowledge on exosome production, secretion, uptake and how exercise influence exosome content. We also highlight recent research development in exosome based approach for cardiac repair.

Hsp72 and Hsp90α mRNA transcription is characterised by large, sustained changes in core temperature during heat acclimation

Increased intracellular heat shock protein-72 (Hsp72) and heat shock protein-90α (Hsp90α) have been implicated as important components of acquired thermotolerance, providing cytoprotection during stress. This experiment determined the physiological responses characterising increases in Hsp72 and Hsp90α mRNA on the first and tenth day of 90-min heat acclimation (in 40.2 °C, 41.0 % relative humidity (RH)) or equivalent normothermic training (in 20 °C, 29 % RH). Pearson's product-moment correlation and stepwise multiple regression were performed to determine relationships between physiological [e.g. (Trec, sweat rate (SR) and heart rate (HR)] and training variables (exercise duration, exercise intensity, work done), and the leukocyte Hsp72 and Hsp90α mRNA responses via reverse transcription quantitative polymerase chain reaction (RT-QPCR) (n = 15). Significant (p < 0.05) correlations existed between increased Hsp72 and Hsp90α mRNA (r = 0.879). Increased core temperature was the most important criteria for gene transcription with ΔTrec (r = 0.714), SR (r = 0.709), Trecfinal45 (r = 0.682), area under the curve where Trec ≥ 38.5 °C (AUC38.5 °C; r = 0.678), peak Trec (r = 0.661), duration Trec ≥ 38.5 °C (r = 0.650) and ΔHR (r = 0.511) each demonstrating a significant (p < 0.05) correlation with the increase in Hsp72 mRNA. The Trec AUC38.5 °C (r = 0.729), ΔTrec (r = 0.691), peak Trec (r = 0.680), Trecfinal45 (r = 0.678), SR (r = 0.660), duration Trec ≥ 38.5 °C (r = 0.629), the rate of change in Trec (r = 0.600) and ΔHR (r = 0.531) were the strongest correlate with the increase in Hsp90α mRNA. Multiple regression improved the model for Hsp90α mRNA only, when Trec AUC38.5 °C and SR were combined. Training variables showed insignificant (p > 0.05) weak (r < 0.300) relationships with Hsp72 and Hsp90α mRNA. Hsp72 and Hsp90α mRNA correlates were comparable on the first and tenth day. When transcription of the related Hsp72 and Hsp90α mRNA is important, protocols should rapidly induce large, prolonged changes in core temperature.

Exercise-induced ROS in heat shock proteins response

Cells have evolved multiple and sophisticated stress response mechanisms aiming to prevent macromolecular (including proteins, lipids, and nucleic acids) damage and to maintain or re-establish cellular homeostasis. Heat shock proteins (HSPs) are among the most highly conserved, ubiquitous, and abundant proteins in all organisms. Originally discovered more than 50 years ago through heat shock stress, they display multiple, remarkable roles inside and outside cells under a variety of stresses, including also oxidative stress and radiation, recognizing unfolded or misfolded proteins and facilitating their restructuring. Exercise consists in a combination of physiological stresses, such as metabolic disturbances, changes in circulating levels of hormones, increased temperature, induction of mild to severe inflammatory state, increased production of reactive oxygen and nitrogen species (ROS and RNS). As a consequence, exercise is one of the main stimuli associated with a robust increase in different HSPs in several tissues, which appears to be also fundamental in facilitating the cellular remodeling processes related to the training regime. Among all factors involved in the exercise-related modulation of HSPs level, the ROS production in the contracting muscle or in other tissues represents one of the most attracting, but still under discussion, mechanism. Following exhaustive or damaging muscle exercise, major oxidative damage to proteins and lipids is likely involved in HSP expression, together with mechanically induced damage to muscle proteins and the inflammatory response occurring several days into the recovery period. Instead, the transient and reversible oxidation of proteins by physiological concentrations of ROS seems to be involved in the activation of stress response following non-damaging muscle exercise. This review aims to provide a critical update on the role of HSPs response in exercise-induced adaptation or damage in humans, focusing on experimental results where the link between redox homeostasis and HSPs expression by exercise has been addressed. Further, with the support of in vivo and in vitro studies, we discuss the putative molecular mechanisms underlying the ROS-mediated modulation of HSP expression and/or activity during exercise.

Pre-Exercise Infrared Low-Level Laser Therapy (810 nm) in Skeletal Muscle Performance and Postexercise Recovery in Humans, What Is the Optimal Dose? A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

AIM

This study aimed to evaluate the medium-term effects of low-level laser therapy (LLLT or photobiomodulation) in postexercise skeletal muscle recovery and performance enhancement and to identify the optimal dose of 810 nm LLLT.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled trial was performed, with voluntary participation of 28 high-level soccer athletes. We analyzed maximum voluntary contraction (MVC), delayed onset muscle soreness (DOMS), creatine kinase (CK) activity, and interleukin-6 (IL-6) expression. The assessments were performed before exercise protocols, after 1 min, and 1, 24, 48, 72, and 96 h after the end of eccentric exercise protocol used to induce fatigue. LLLT was applied before eccentric exercise protocol with a cluster with five diodes, and dose of 10, 30, or 50 J (200 mW and 810 nm) in six sites of quadriceps.

RESULTS

LLLT increased (p < 0.05) MVC from immediately after exercise to 24 h with 50 J dose, and from 24 to 96 h with 10 J dose. Both 10 J then 50 J dose decreased (p < 0.05) CK and IL-6 with better results in favor of 50 J dose. However, LLLT had no effect in decreasing DOMS. No differences (p > 0.05) were found for 30 J dose in any of the outcomes measured.

CONCLUSIONS

Pre-exercise LLLT, mainly with 50 J dose, significantly increases performance and improves biochemical markers related to skeletal muscle damage and inflammation.

Salivary extracellular heat shock protein 70 (eHSP70) levels increase after 59 min of intense exercise and correlate with resting salivary secretory immunoglobulin A (SIgA) levels at rest

This study aimed to identify the response of a salivary stress protein, extracellular heat shock protein (eHSP70), to intense exercise and to investigate the relationship between salivary eHSP70 and salivary immunoglobulin A (SIgA) levels in response to exercise. Sixteen healthy sedentary young males (means ± SD 23.8 ± 1.5 years, 172.2 ± 6.4 cm, 68.3 ± 7.4 kg) performed 59 min of cycling exercise at 75% VO2max. Saliva and whole blood samples were collected before (Pre), immediately after (Post), and at 1, 2, 3, and 4 h after completion of the exercise (1, 2, 3, and 4 h). The salivary eHSP70 and SIgA levels were measured by enzyme-linked imunosorbent assay (ELISA), and the secretion rates were computed by multiplying the concentration by the saliva flow rate. White blood cells were analyzed using an automated cell counter with a direct-current detection system. The salivary eHSP70 secretion rates were 1.11 ± 0.86, 1.51 ± 1.47, 1.57 ± 1.32, 2.21 ± 2.04, 3.36 ± 2.72, and 6.89 ± 4.02 ng · min(-1) at Pre, Post, and 1, 2, 3, and 4 h, respectively. The salivary eHSP70 secretion rate was significantly higher at 4 h than that at Pre, Post, 1, and 3 h (p < 0.05). The SIgA secretion rates were 26.9 ± 12.6, 20.3 ± 10.4, 19.6 ± 11.0, 21.8 ± 12.8, 21.5 ± 11.9, and 21.9 ± 11.7 μg · min(-1) at Pre, Post, 1, 2, 3, and 4 h, respectively. The salivary SIgA secretion rate was significantly lower between 1 and 4 h than that at Pre (p < 0.05). There was a positive correlation between salivary eHSP70 and SIgA in both concentration and secretion rates before exercise (p < 0.05). The absolute number of white blood cells significantly increased after exercise, with a maximum at 2 h (p < 0.05). The neutrophil/lymphocyte ratio was significantly increased from 1 to 4 h when compared with that in the Pre samples (p < 0.05). The present study revealed that salivary eHSP70 significantly increased at 4 h after the 59 min of intense exercise in sedentary male subjects. Exercise stress can induce elevated salivary eHSP70 level and upregulate oral immune function partially.

Heat shock response and autophagy--cooperation and control

Protein quality control (proteostasis) depends on constant protein degradation and resynthesis, and is essential for proper homeostasis in systems from single cells to whole organisms. Cells possess several mechanisms and processes to maintain proteostasis. At one end of the spectrum, the heat shock proteins modulate protein folding and repair. At the other end, the proteasome and autophagy as well as other lysosome-dependent systems, function in the degradation of dysfunctional proteins. In this review, we examine how these systems interact to maintain proteostasis. Both the direct cellular data on heat shock control over autophagy and the time course of exercise-associated changes in humans support the model that heat shock response and autophagy are tightly linked. Studying the links between exercise stress and molecular control of proteostasis provides evidence that the heat shock response and autophagy coordinate and undergo sequential activation and downregulation, and that this is essential for proper proteostasis in eukaryotic systems.

Moderate- and high-intensity exhaustive exercise in the heat induce a similar increase in monocyte Hsp72

This study examined the relationship between exhaustive exercise in the heat at moderate and high intensities on the intracellular heat shock protein 72 (iHsp72) response. Twelve male subjects cycled to exhaustion at 60 and 75% of maximal oxygen uptake in hot conditions (40 °C, 50% RH). iHsp72 concentration was measured in monocytes before, at exhaustion and 24 h after exercise. Rectal temperature, heart rate and oxygen uptake were recorded during exercise. Volitional exhaustion occurred at 58.9 ± 12.1 and 27.3 ± 9.5 min (P < 0.001) and a rectal temperature of 39.8 ± 0.4 and 39.2 ± 0.6 °C (P = 0.002), respectively, for 60 and 75 %. The area under the curve above a rectal temperature of 38.5 °C was greater at 60 % (17.5 ± 6.6 °C min) than 75 % (3.4 ± 4.8 °C min; P < 0.001), whereas the rate of increase in rectal temperature was greater at 75 % (5.1 ± 1.7 vs. 2.2 ± 1.4 °C h(-1); P < 0.001). iHsp72 concentration increased similarly at exhaustion relative to pre-exercise (P = 0.044) and then increased further at 24 h (P < 0.001). Multiple regression analysis revealed no predictor variables associated with iHsp72 expression; however, a correlation was observed between exercise intensities for the increase in iHsp expression at exhaustion and 24 h (P < 0.05). These results suggest that iHsp72 expression increased in relation to the level of hyperthermia attained and sustained at 60 % and the higher metabolic rate and greater rate of increase in core temperature at 75 %, with the further increase in iHsp72 concentration 24 h after exercise reinforcing its role as a chaperone and cytoprotective agent.

Effects of Exercise on Gene Expression of Inflammatory Markers in Human Peripheral Blood Cells: A Systematic Review

Regular physical activity seems to be one of the most important contributors to prevent disease and promote health. Being physically active reduces the risk of developing chronic diseases such as cardiovascular disease, diabetes, and some types of cancers. The molecular mechanisms are however not fully elucidated. Depending on duration and intensity, exercise will cause disruption of muscle fibers triggering a temporary inflammatory response. This response may not only involve the muscle tissue, but also peripheral tissues such as white blood cells, which are important components of the immune system. The immune system plays a vital role in the development of atherosclerosis, thereby making white blood cells relevant to study when looking at molecular mechanisms induced by physical activity. In this review, we summarize the existing literature on exercise and gene expression in human white blood cells, and discuss these results in relation to inflammation and atherosclerosis.

PBMCs express a transcriptome signature predictor of oxygen uptake responsiveness to endurance exercise training in men

Peripheral blood cells are an accessible environment in which to visualize exercise-induced alterations in global gene expression patterns. We aimed to identify a peripheral blood mononuclear cell (PBMC) signature represented by alterations in gene expression, in response to a standardized endurance exercise training protocol. In addition, we searched for molecular classifiers of the variability in oxygen uptake (V̇o2). Healthy untrained policemen recruits (n = 13, 25 ± 3 yr) were selected. Peak V̇o2 (measured by cardiopulmonary exercise testing) and total RNA from PBMCs were obtained before and after 18 wk of running endurance training (3 times/wk, 60 min). Total RNA was used for whole genome expression analysis using Affymetrix GeneChip Human Gene 1.0 ST. Data were normalized by the robust multiarray average algorithm. Principal component analysis was used to perform correlations between baseline gene expression and V̇o2peak. A set of 211 transcripts was differentially expressed (ANOVA, P < 0.05 and fold change > 1.3). Functional enrichment analysis revealed that transcripts were mainly related to immune function, cell cycle processes, development, and growth. Baseline expression of 98 and 53 transcripts was associated with the absolute and relative V̇o2peak response, respectively, with a strong correlation (r > 0.75, P < 0.01), and this panel was able to classify the 13 individuals according to their potential to improve oxygen uptake. A subset of 10 transcripts represented these signatures to a similar extent. PBMCs reveal a transcriptional signature responsive to endurance training. Additionally, a baseline transcriptional signature was associated with changes in V̇o2peak. Results might illustrate the possibility of obtaining molecular classifiers of endurance capacity changes through a minimally invasive blood sampling procedure.

Dietary ascorbic acid modulates the expression profile of stress protein genes in hepatopancreas of adult Pacific abalone Haliotis discus hannai Ino

This study was conducted to investigate the effects of dietary ascorbic acid (AA) on transcriptional expression patterns of antioxidant proteins, heat shock proteins (HSP) and nuclear factor kappa B (NF-κB) in the hepatopancreas of Pacific abalone Haliotis discus hannai Ino (initial average length: 84.36 ± 0.24 mm) using real-time quantitative PCR assays. L-ascorbyl-2-molyphosphate (LAMP) was added to the basal diet to formulate four experimental diets containing 0.0, 70.3, 829.8 and 4967.5 mg AA equivalent kg(-1) diets, respectively. Each diet was fed to triplicate groups of adult abalone in acrylic tanks (200 L) in a flow-through seawater system. Each tank was stocked with 15 abalone. Animals were fed once daily (17:00) to apparent satiation for 24 weeks. The results showed that the dietary AA (70.3 mg kg(-1)) could significantly up-regulate the expression levels of Cu/Zn superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), feritin (FT) and heat shock protein 26 (HSP26) in the hepatopancreas of abalone in this treatment compared to the controls. However, the expression levels of Mn-SOD, glutathione peroxidase (GPX), thioredoxin peroxidase (TPx), selenium-binding protein (SEBP), HSP70 and HSP90 were significantly down-regulated. Compared with those in the group with 70.3 mg kg(-1) dietary AA, the expression levels of CAT, GST and HSP26 were decreased in abalone fed with very high dietary AA (4967.5 mg kg(-1)). In addition, significant up-regulations of expression levels of Mn-SOD, GPX, TPx, SEBP, FT, HSP70, HSP90 and NF-κB were observed in abalone fed with apparently excessive dietary AA (829.8 and 4967.5 mg kg(-1)) as compared to those fed 70.3 mg kg(-1) dietary AA. These findings showed that dietary AA influenced the expression levels of antioxidant proteins, heat shock proteins and NF-κB in the hepatopancreas of abalone at transcriptional level. Levels of dietary AA that appeared adequate (70.3 mg kg(-1)) reduced the oxidative stress by influencing gene expression of antioxidant proteins, but excessive dietary AA (829.8 and 4967.5 mg kg(-1)) induced oxidative stress in Pacific abalone H. discus hannai.

Role of Toll-like receptor 2 and 4 signaling pathways on the inflammatory response to resistance training in elderly subjects

This study assessed the effects of a resistance exercise training program on the inflammatory response associated with Toll-like receptor (TLR) 2 and TLR4 signaling pathways in senior participants. Twenty-six healthy subjects (age, 69.5 ± 1.3) were randomized to a training (TG; n = 16) or a control (CG; n = 10) group. TG performed an 8-week resistance training program, while CG followed their daily routines. Peripheral blood mononuclear cells were isolated from blood samples obtained before and after the intervention, and levels of proteins involved in the TLR2, TLR4, and myeloid differentiation primary response gene 88 (MyD88)-dependent and MyD88-independent pathways were analyzed. The inflammatory status was evaluated through messenger RNA (mRNA) and protein content of interleukin (IL)-10 and tumor necrosis factor alpha (TNF-α) and plasma levels of C-reactive protein (CRP). After the 8-week resistance training, TLR2 and TLR4 protein expression was reduced in TG. MyD88, p65, phospho-p38, TIR domain-containing adaptor inducing interferon (TRIF), IKKi/IKKε, phospho-interferon regulatory factor (IRF) 3, and phosho-IRF7 were also downregulated in TG after the intervention. The training program induced an increase of phospho-extracellular signal-regulated kinases 1 and 2 (ERK1/2) and Hsp70 and a reduction of Hsp60. While TNF-α mRNA and protein values remained unchanged in both TG and CG, IL-10 mRNA and protein content were upregulated in TG after the intervention. CRP values decreased in TG only. The increase in Hsp70 negatively correlated with TLR2 and TLR4 downregulation. These data suggest that resistance exercise may represent an effective tool to ameliorate the pro-inflammatory status of old participants through an attenuation of MyD88-dependent and MyD88-independent TLR2 and TLR4 signaling pathways.

Cardiac Damage Biomarkers Following a Triathlon in Elite and Non-elite Triathletes

The purpose of the present study was to investigate cardiac damage biomarkers after a triathlon race in elite and non-elite athlete groups. Fifteen healthy men participated in the study. Based on performance, they were divided into elite athlete group (EG: n=7) and non-elite athlete group (NEG: n=8). Participants' blood samples were obtained during four periods: before, immediately, 2 hours and 7 days after finishing the race. creatine kinase (CK), creatine kinase-myoglobin (CK-MB), myoglobin, and lactate dehydrogenase (LDH) were significantly increased in both groups immediately after, and 2 hours after finishing the race (p<.05). CK, CK-MB, and myoglobin were completely recovered after 7 days (p<.05). Hematocrit (Hct) was significantly decreased in both groups (p<.05) 7 days after the race. LDH was significantly decreased in the EG (p<.05) only 7 days after the race. Homoglobin (Hb) was significantly decreased in the NEG (p<.05) only 2 hours after the race. Although cardiac troponin T (cTnT) was significantly increased in the EG but not in the NEG 2hours after the race (p<.05), there was no group-by-time interaction. cTnT was completely recovered in both groups 7 days after the race. In conclusion, cardiac damage occurs during a triathlon race and, is greater in elite than in non-elite. However, all cardiac damage markers return to normal range within 1 week.

Direct measurement of cell-free DNA from serially collected capillary plasma during incremental exercise

To investigate the kinetics of cell-free DNA (cfDNA) due to exercise, we established a direct real-time PCR for the quantification of cfDNA from unpurified capillary plasma by amplification of a 90- and a 222-bp multilocus L1PA2 sequence. Twenty-six male athletes performed an incremental treadmill test. For cfDNA measurement, capillary samples were collected serially from the fingertip preexercise, during, and several times postexercise. Venous blood was drawn before and immediately after exercise to compare capillary and venous cfDNA values. To elucidate the strongest association of cfDNA accumulations with either cardiorespiratory or metabolic function during exercise, capillary cfDNA values were correlated with standard measures like heart rate, oxygen consumption, or lactate concentrations. The venous cfDNA concentrations were significantly higher compared with the capillary plasma, but in both fractions cfDNA increased 9.8-fold and the values correlated significantly ( r = 0.796). During incremental treadmill running, the capillary cfDNA concentrations increased nearly parallel to the lactate values. The values correlated best with heart rate and energy expenditure, followed by oxygen consumption, Borg values, and lactate levels (0.710 ≤ r ≥ 0.808). With this article, we present a sensitive procedure for the direct quantification of cfDNA in unpurified capillary plasma instead of purified venous plasma. Further studies should investigate the differences between capillary and venous cfDNA that might mirror different physiological mechanisms. Enhanced cardiorespiratory function during exercise might lead to the accumulation of cfDNA via the release of stress hormones that already increase at intensities below the anaerobic threshold. Furthermore, cfDNA might be released by neutrophil extracellular traps.

Humid heat exposure induced oxidative stress and apoptosis in cardiomyocytes through the angiotensin II signaling pathway

Exposure to humid heat stress leads to the initiation of serious physiological dysfunction that may result in heat-related diseases, including heat stroke, heat cramp, heat exhaustion, and even death. Increasing evidences have shown that the humid heat stress-induced dysfunction of the cardiovascular system was accompanied with severe cardiomyocyte injury; however, the precise mechanism of heat stress-induced injury of cardiomyocyte remains unknown. In the present study, we hypothesized that humid heat stress promoted oxidative stress through the activation of angiotensin II (Ang II) in cardiomyocytes. To test our hypothesis, we established mouse models of humid heat stress. Using the animal models, we found that Ang II levels in serum were significantly up-regulated and that the Ang II receptor AT1 was increased in cardiomyocytes. The antioxidant ability in plasma and heart tissues which was detected by the ferric reducing/antioxidant power assay was also decreased with the increased ROS production under humid heat stress, as was the expression of antioxidant genes (SOD2, HO-1, GPx). Furthermore, we demonstrated that the Ang II receptor antagonist, valsartan, effectively relieved oxidative stress, blocked Ang II signaling pathway and suppressed cardiomyocyte apoptosis induced by humid heat stress. In addition, overexpression of antioxidant genes reversed cardiomyocyte apoptosis induced by Ang II. Overall, these results implied that humid heat stress increased oxidative stress and caused apoptosis of cardiomyocytes through the Ang II signaling pathway. Thus, targeting the Ang II signaling pathway may provide a promising approach for the prevention and treatment of cardiovascular diseases caused by humid heat stress.

Sex differences in heat shock protein 72 expression in peripheral blood mononuclear cells to acute exercise in the heat

BACKGROUND

Heat shock protein 72 (Hsp72) is responsible for maintaining critical cellular function during heat stress. Hsp72 confers thermotolerance and may play a role in heat acclimation. Animal research suggests a difference between sexes in Hsp72 expression in response to exercise, however, human data is lacking.

OBJECTIVES

To determine sex differences in intracellular heat shock protein 72 (Hsp72) following exercise in the heat.

PATIENTS AND METHODS

Nine non-heat acclimated women with normal menstrual cycles (VO2pk 58 ± 5 mL.kgFFM(-1).min(-1)) and nine non-heat acclimated men (VO2pk 60 ± 7 ml.kgFFM(-1).min(-1)) completed 2 treadmill bouts at 60% VO2pk for 60 min in a 42°C, 20% RH environment. Women were tested in follicular (fol) and luteal (lut) phases. The duplicate trials were separated by 12 days for men and women. Blood samples were drawn pre, immediately post, 1, and 4 hrs post-exercise.

RESULTS

Men and women differed in their Hsp72 response after exercise (time X sex X trial interaction; P < 0.05). Men increased Hsp72 after exercise more than women. Both men and women produced less Hsp72 during trial 2 compared to trial 1. Estrogen (r = 0.24; P > 0.05) and progesterone (r = 0.27, P > 0.05) concentrations were not correlated with Hsp72.

CONCLUSION

Our findings suggest that men and women differ in their cellular stress response. Men up-regulated Hsp72 after a single bout of exercise in the heat, which persists for 12 days, suggesting an accumulation of Hsp72 which may lead to acquired cellular thermotolerance.

Leukocyte chemotactic cytokine and leukocyte subset responses during ultra-marathon running

PURPOSE

The aim of this study was to assess leukocyte chemotactic cytokine and leukocyte subset responses during ultra-marathon running. Leukocyte chemokines such as interleukin (IL)-8, interferon gamma-induced protein-10 (IP-10), regulated upon activation, normal T-cell expressed and secreted (RANTES), and eotaxin are involved in leukocyte recruitment.

METHODS

Among 60 male amateur endurance runner volunteers, 18 finished the course (a 308 km continuous race from Kanghwado to Kangneung, South Korea). Their average age, height, and body mass were 52.8 ± 5.0 years, 167.6 ± 5.2 cm, and 64.5 ± 1.2 kg, respectively. Blood samples were collected at 0, 100, 200, and 308 km during the race for analysis of white blood cells and serum concentrations of IL-8, IP-10, RANTES, eotaxin, IL-6, creatine kinase (CK), and C-reactive protein (CRP).

RESULTS

Muscle and liver damage indicators (IL-6, CK, and CRP) were maximally elevated as a result of marathon running. Total leukocytes, neutrophils, and monocytes increased significantly during the event (leukocytosis, neutrophilia, and monocytosis, respectively). However, lymphocytes and eosinophils decreased significantly during the event (lymphopenia and eosinopenia, respectively). Serum levels of the neutrophil chemokine IL-8 increased maximally at 100 km and were maintained. Monocyte-lymphocyte chemokine IP-10 concentration decreased during the latter part of the race. The eosinophil chemokine eotaxin decreased gradually during the race, and no difference was observed in eosinophil chemokine RANTES levels.

CONCLUSION

These observations indicate that prolonged endurance ultra-marathon running was associated with significant systemic inflammation and perturbation in leukocyte subsets. Leukocyte chemotactic cytokines such as IL-8, IP-10, eotaxin showed similar patterns of responses in related leukocyte subsets, but RANTES did not.

Circulating cell-free DNA: an up-coming molecular marker in exercise physiology

The phenomenon of circulating cell-free DNA (cfDNA) concentrations is of importance for many biomedical disciplines including the field of exercise physiology. Increases of cfDNA due to exercise are described to be a potential hallmark for the overtraining syndrome and might be related to, or trigger adaptations of, immune function induced by strenuous exercise. At the same time, exercise provides a practicable model for studying the phenomenon of cfDNA that is described to be of pathophysiological relevance for different topics in clinical medicine like autoimmune diseases and cancer. In this review, we are summarizing the current knowledge of exercise-based acute and chronic alterations in cfDNA levels and their physiological significance. The effects of acute exercise on cfDNA concentrations have been investigated in resistance exercises and in continuous, stepwise and interval endurance exercises of different durations. cfDNA concentrations peaked immediately after acute exercise and showed a rapid return to baseline levels. Typical markers of skeletal muscle damage (creatine kinase, uric acid, C-reactive protein) show delayed kinetics compared with the cfDNA peak response. Exercise parameters such as intensity, duration or average energy expenditure do not explain the extent of increasing cfDNA concentrations after strenuous exercise. This could be due to complex processes inside the human organism during and after physical activity. Therefore, we hypothesize composite effects of different physiological stress parameters that come along with exercise to be responsible for increasing cfDNA concentrations. We suggest that due to acute stress, cfDNA levels increase rapidly by a spontaneous active or passive release mechanism that is not yet known. As a result of the rapid and parallel increase of cfDNA and lactate in an incremental treadmill test leading to exhaustion within 15-20 minutes, it is unlikely that cfDNA is released into the plasma by typical necrosis or apoptosis of cells in acute exercise settings. Recently, rapid DNA release mechanisms of activated immune-competent cells like NETosis (pathogen-induced cell death including the release of neutrophil extracellular traps [NETs]) have been discovered. cfDNA accumulations might comprise a similar kind of cell death including trap formation or an active release of cfDNA. Just like chronic diseases, chronic high-intensity resistance training protocols induced persistent increases of cfDNA levels. Chronic, strenuous exercise protocols, either long-duration endurance exercise or regular high-intensity workouts, induce chronic inflammation that might lead to a slow, constant release of DNA. This could be due to mechanisms of cell death like apoptosis or necrosis. Yet, it has neither been implicated nor proven sufficiently whether cfDNA can serve as a marker for overtraining. The relevance of cfDNA with regard to overtraining status, performance level, and the degree of physical exhaustion still remains unclear. Longitudinal studies are required that take into account standardized and controlled exercise, serial blood sampling, and large and homogeneous cohorts of different athletic achievement. Furthermore, it is important to establish standardized laboratory procedures for the measurement of genomic cfDNA concentrations by quantitative real-time polymerase chain reaction (PCR). We introduce a new hypothesis based on acute exercise and chronic exposure to stress, and rapid active and passive chronic release of cfDNA fragments into the circulation.

The intersection of inflammation, insulin resistance and ageing: implications for the study of molecular signalling pathways in horses

Inflammation-associated insulin resistance contributes to chronic disease in humans and other long-lived species, such as horses. Insulin resistance arises due to an imbalance among molecular signalling mediators in response to pro-inflammatory cytokines in the aged and obese. The mammalian heat shock protein response has received much attention as an avenue for attenuating inflammatory mediator signalling and for contributing to preservation and restoration of insulin signalling in metabolically important tissues. Data on heat shock proteins and inflammatory signalling mediators in untrained and aged horses are lacking, and horses represent an untapped resource for studying the mediator imbalance contributing to insulin resistance in a comparative model.

Exercise-induced dehydration with and without environmental heat stress results in increased oxidative stress

While in vitro work has revealed that dehydration and hyperthermia can elicit increased cellular and oxidative stress, in vivo research linking dehydration, hyperthermia, and oxidative stress is limited. The purpose of this study was to investigate the effects of exercise-induced dehydration with and without hyperthermia on oxidative stress. Seven healthy male, trained cyclists (power output (W) at lactate threshold (LT): 199 ± 19 W) completed 90 min of cycling exercise at 95% LT followed by a 5-km time trial (TT) in 4 trials: (i) euhydration in a warm environment (EU-W, control), (ii) dehydration in a warm environment (DE-W), (iii) euhydration in a thermoneutral environment (EU-T), and (iv) dehydration in a thermoneutral environment (DE-T) (W: 33.9 ± 0.9 °C; T: 23.0 ± 1.0 °C). Oxidized glutathione (GSSG) increased significantly postexercise in dehydration trials only (DE-W: p < 0.01, DE-T: p = 0.03), and while not significant, total glutathione (TGSH) and thiobarbituric acid reactive substances (TBARS) tended to increase postexercise in dehydration trials (p = 0.08 for both). Monocyte heat shock protein 72 (HSP72) concentration was increased (p = 0.01) while lymphocyte HSP32 concentration was decreased for all trials (p = 0.02). Exercise-induced dehydration led to an increase in GSSG concentration while maintenance of euhydration attenuated these increases regardless of environmental condition. Additionally, we found evidence of increased cellular stress (measured via HSP) during all trials independent of hydration status and environment. Finally, both 90-min and 5-km TT performances were reduced during only the DE-W trial, likely a result of combined cellular stress, hyperthermia, and dehydration. These findings highlight the importance of fluid consumption during exercise to attenuate thermal and oxidative stress during prolonged exercise in the heat.

Passing the anaerobic threshold is associated with substantial changes in the gene expression profile in white blood cells

High and moderate intensity endurance exercise alters gene expression in human white blood cells (WBCs), but the understanding of how this effect occurs is limited. To increase our knowledge of the nature of this process, we investigated the effects of passing the anaerobic threshold (AnT) on the gene expression profile in WBCs of athletes. Nineteen highly trained skiers participated in a treadmill test with an incremental step protocol until exhaustion (ramp test to exhaustion, RTE). The average total time to exhaustion was 14:40 min and time after AnT was 4:50 min. Two weeks later, seven of these skiers participated in a moderate treadmill test (MT) at 80% peak O(2) uptake for 30 min, which was slightly below their AnTs. Blood samples were obtained before and immediately after both tests. RTE was associated with substantially greater leukocytosis and acidosis than MT. Gene expression in WBCs was measured using whole genome microarray expression analysis before and immediately after each test. A total of 310 upregulated genes were found after RTE, and 69 genes after MT of which 64 were identical to RTE. Both tests influenced a variety of known gene pathways related to inflammation, stress response, signal transduction and apoptosis. A large group of differentially expressed previously unknown small nucleolar RNA and small Cajal body RNA was found. In conclusion, a 15-min test to exhaustion was associated with substantially greater changes of gene expression than a 30-min test just below the AnT.

Pre-exercise alkalosis attenuates the heat shock protein 72 response to a single-bout of anaerobic exercise

The heat shock protein 72 (HSP72) response following exercise is well documented, however, little is known on whether the expression may be mediated by the ingestion of ergogenic aids prior to performance. The purpose of this research was to investigate the effect of sodium bicarbonate (NaHCO(3)) ingestion on monocyte and lymphocyte expressed HSP72 and oxidative stress for 4-h post exercise. Seven active males (22.3 ± 2.9 years, 181.6 ± 4.5 cm, 78.1 ± 8.1 kg) performed a 4-min 'all-out' cycle test following a dose of 0.3 g kg(-1) body mass of NaHCO(3), or an equimolar placebo dose of sodium chloride. HSP72 was measured by flow cytometry and oxidative stress was determined via plasma thiobarbituric acid substances (TBARS) analysis. The NaHCO(3) ingestion significantly increased blood pH (p<0.001), bicarbonate (p<0.001) and base excess (p<0.001) pre-exercise. Despite this there was no evidence of a significantly improved exercise performance when compared with the placebo trials (p ≥ 0.26) (means ± SD; average power 292 ± 43 W vs. 291 ± 50 W; peak power 770 ± 218 W vs. 775 ± 211 W; work completed 71 ± 10 kJ vs. 68 ± 10 kJ). Monocyte expressed HSP72 was significantly lower under experimental conditions during the 4-h post-exercise (p=0.013), as was plasma TBARS (p<0.001). These findings suggest that pre-exercise alkalosis can attenuate the stress response to a single bout of anaerobic exercise.

Comparison between cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) in short-term skeletal muscle recovery after high-intensity exercise in athletes--preliminary results

In the last years, phototherapy has becoming a promising tool to improve skeletal muscle recovery after exercise, however, it was not compared with other modalities commonly used with this aim. In the present study we compared the short-term effects of cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) with placebo LEDT on biochemical markers related to skeletal muscle recovery after high-intensity exercise. A randomized double-blind placebo-controlled crossover trial was performed with six male young futsal athletes. They were treated with CWIT (5°C of temperature [SD ±1°]), active LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW of output power, 30 s of irradiation time per point, and 41.7 J of total energy irradiated per point, total of ten points irradiated) or an identical placebo LEDT 5 min after each of three Wingate cycle tests. Pre-exercise, post-exercise, and post-treatment measurements were taken of blood lactate levels, creatine kinase (CK) activity, and C-reactive protein (CRP) levels. There were no significant differences in the work performed during the three Wingate tests (p > 0.05). All biochemical parameters increased from baseline values (p < 0.05) after the three exercise tests, but only active LEDT decreased blood lactate levels (p = 0.0065) and CK activity (p = 0.0044) significantly after treatment. There were no significant differences in CRP values after treatments. We concluded that treating the leg muscles with LEDT 5 min after the Wingate cycle test seemed to inhibit the expected post-exercise increase in blood lactate levels and CK activity. This suggests that LEDT has better potential than 5 min of CWIT for improving short-term post-exercise recovery.

Acute in vitro hypoxia and high-altitude (4,559 m) exposure decreases leukocyte oxygen consumption

Hypoxia impairs metabolic functions by decreasing activity and expression of ATP-consuming processes. To separate hypoxia from systemic effects, we tested whether hypoxia at high altitude affects basal and PMA-stimulated leukocyte metabolism and how this compares to acute (15 min) and 24 h of in vitro hypoxia. Leukocytes were prepared at low altitude and ∼24 h after arrival at 4559 m. Mitochondrial oxygen consumption (JO₂) was measured by respirometry, oxygen radicals by electron spin resonance spectroscopy, both at a Po₂ = 100 mmHg (JO₂,₁₀₀) and 20 mmHg (JO₂,₂₀). Acute hypoxia of leukocytes decreased JO₂ at low altitude. Exposure to high altitude decreased JO₂,₁₀₀, whereas JO₂,₂₀ was not affected. Acute hypoxia of low-altitude samples decreased the activity of complexes I, II, and III. At high altitude, activity of complexes I and III were decreased when measured in normoxia. Stimulation of leukocytes with PMA increased JO₂,₁₀₀ at low (twofold) and high altitude (five-fold). At both locations, PMA-stimulated JO₂ was decreased by acute hypoxia. Basal and PMA-stimulated reactive oxygen species (ROS) production were unchanged at high altitude. Separate in vitro experiments performed at low altitude show that ∼75% of PMA-induced increase in JO₂ was due to increased extra-mitochondrial JO₂ (JO₂(,res); in the presence of rotenone and antimycin A). JO₂(,res) was doubled by PMA. Acute hypoxia decreased basal JO₂(,res) by ∼70% and PMA-stimulated JO₂(,res) by about 50% in cells cultured in normoxia and hypoxia (1.5% O₂; 24 h). Conversely, 24 h in vitro hypoxia decreased mitochondrial JO₂,₁₀₀ and JO₂,₂₀, extra-mitochondrial, basal, and PMA-stimulated JO₂ were not affected. These results show that 24 h of high altitude but not 24 h in vitro hypoxia decreased basal leukocyte metabolism, whereas PMA-induced JO₂ and ROS formation were not affected, indicating that prolonged high-altitude hypoxia impairs mitochondrial metabolism but does not impair respiratory burst. In contrast, acute hypoxia impairs respiratory burst at either altitude.