Evidence of a Redox-Dependent Regulation of Immune Responses to Exercise-Induced Inflammation

The Effect of Protein Supplementation and Playing Time on Recovery Kinetics During a Congested Basketball Schedule

BACKGROUND/OBJECTIVES

Despite being widely promoted, protein supplementation's overall effectiveness during demanding basketball schedules remains unclear. This study investigated whether increased protein intake can accelerate recovery of muscle function during a 6-day congested basketball microcycle consisting of three consecutive games while accounting for the impact of playing time.

METHODS

In a randomized, two-trial, cross-over, double-blind repeated measures design, eighteen male basketball players were assigned to a high (High PT) or a moderate (Mod PT) playing time group and participated in two trials, receiving daily either milk protein (PRO trial) or an isoenergetic amount of carbohydrates. Each trial included three consecutive games (days 1-3) and a 72 h recovery period following Game 3 (days 4-6), during which players participated in low-load practice sessions. Isometric and isokinetic peak torque of knee extensors and flexors in the dominant limb, serum creatine kinase (CK) concentration, and erythrocyte glutathione (GSH) levels were assessed prior to each game and practice session.

RESULTS

CK increased (p < 0.01) on game days in both groups but recovered earlier in Mod PT compared to High PT. Both eccentric and concentric peak torque was impaired (p < 0.01) up to 24-48 h post-G3 in a velocity-dependent manner. Eccentric peak torque of knee flexors at 60°/s declined to a greater extent in High PT compared to Mod PT (p < 0.01). Protein supplementation resulted in higher erythrocyte GSH concentration at pre-G2 (p < 0.05) and pre-G3 (p < 0.05) compared to placebo in both groups but did not affect any of the study outcomes.

CONCLUSIONS

Increased protein intake during a congested basketball schedule increases erythrocyte GSH concentration but does not accelerate recovery of muscle function.

The impact of N-acetylcysteine on lactate, biomarkers of oxidative stress, immune response, and muscle damage: A systematic review and meta-analysis

N-acetylcysteine (NAC) is a compound whose mechanism of action is intricately linked to the provision of cysteine for glutathione synthesis. It has been used in medicine and has also made significant inroads into sports, as it can modify the levels of several biomarkers, including those of oxidative processes, inflammation and muscle damage after exercise. Because the effectiveness of NAC supplementation is unclear, the primary objective of the present study was to perform a meta-analysis elucidating how NAC supplementation alters the concentrations of GSH (glutathione), GSSG (glutathione disulfide), TBARS (thiobarbituric acid reactive substances), IL-6 (interleukin 6), TNF-α (tumour necrosis factor alpha), CK (creatine kinase), lactate, and muscle soreness after physical exertion. Suitable studies were searched for from February to September 2023, and the results of those included (n = 20) indicate that NAC supplementation significantly diminishes both muscle soreness (p = 0.03; the mean difference (MD) of NAC's effect was -0.43 with a 95% confidence interval (CI), -0.81, -0.04) and lactate concentrations after exercise (p = 0.03; the MD -0.56 mmol/L; 95% CI, -1.07, -0.06). A substantial decrease was observed in concentrations of IL-6 (p = 0.03; the standardized MD (SMD) was -1.71; 95% CI, -3.26, -0.16) and TBARS (p = 0.02; SMD was -1.03, 95% CI, -1.90, -0.15). Furthermore, an elevation in GSH concentration was observed following supplementation. However, we saw no significant effect of NAC on TNF-α, CK or GSSG concentrations. NAC supplementation holds promise for attenuating muscle soreness, lactate, TBARS and IL-6 concentrations and increasing GSH level following physical exertion.

Recovery kinetics following eccentric exercise is volume-dependent

The present study compared the effect of 75 vs 150 vs 300 intensity-matched eccentric contractions on muscle damage and performance recovery kinetics. Ten healthy males participated in a randomized, cross-over study consisted of 4 experimental trials (ECC75, ECC150, ECC300 and Control - no exercise) with a 4-week washout period in-between. Performance and muscle damage, inflammatory and oxidative stress markers were evaluated at baseline, post-exercise, 24, 48 and 192 hours following each exercise protocol. Concentric and eccentric peak torque decreased similarly in ECC150 and ECC300 during the first 48 h of recovery (p < 0.05) but remained unaffected in ECC75. Countermovement jump indices decreased post-exercise and at 24 h in ECC150 and ECC300, with ECC300 inducing a more pronounced reduction (p < 0.05). Creatine kinase increased until 48 h of recovery in all trials and remained elevated up to 192 h only in ECC300 (p < 0.05). Delayed onset of muscle soreness increased, and knee-joint range of motion decreased in a volume-dependent manner during the first 48 h (p < 0.05). Likewise, a volume-dependent decline of glutathione and a rise of protein carbonyls was observed during the first 48 h of recovery (p < 0.05). Collectively, our results indicate that muscle damage and performance recovery following eccentric exercise is volume dependent, at least in lower limbs.

Transcriptome-Based Identification of the Muscle Tissue-Specific Expression Gene CKM and Its Regulation of Proliferation, Apoptosis and Differentiation in Chicken Primary Myoblasts

Skeletal muscle is an essential tissue in meat-producing animals, and meat-producing traits have been a hot topic in chicken genetic breeding research. Current research shows that creatine kinase M-type-like (CKM) is one of the most abundant proteins in skeletal muscle and plays an important role in the growth and development of skeletal muscle, but its role in the development of chicken skeletal muscle is still unclear. Via RNA sequencing (RNA-seq), we found that CKM was highly expressed in chicken breast muscle tissue. In this study, the expression profile of CKM was examined by quantitative real-time PCR (qPCR), and overexpression and RNA interference techniques were used to explore the functions of CKM in the proliferation, apoptosis and differentiation of chicken primary myoblasts (CPMs). It was shown that CKM was specifically highly expressed in breast muscle and leg muscle and was highly expressed in stage 16 embryonic muscle, while CKM inhibited proliferation, promoted the apoptosis and differentiation of CPMs and was involved in regulating chicken myogenesis. Transcriptome sequencing was used to identify genes that were differentially expressed in CPMs after CKM disruption, and bioinformatics analysis showed that CKM was involved in regulating chicken myogenesis. In summary, CKM plays an important role in skeletal muscle development during chicken growth and development.

Skeletal muscle and erythrocyte redox status is associated with dietary cysteine intake and physical fitness in healthy young physically active men

PURPOSE

To investigate the association between redox status in erythrocytes and skeletal muscle with dietary nutrient intake and markers of physical fitness and habitual physical activity (PA).

METHODS

Forty-five young physically active men were assessed for body composition, dietary nutrient intake, muscle strength, cardiorespiratory capacity and habitual PA. Blood and muscle samples were collected to estimate selected redox biomarkers. Partial correlation analysis was used to evaluate the independent relationship of each factor with redox biomarkers.

RESULTS

Dietary cysteine intake was positively correlated (p < 0.001) with both erythrocyte (r = 0.697) and muscle GSH (0.654, p < 0.001), erythrocyte reduced/oxidized glutathione ratio (GSH/GSSG) (r = 0.530, p = 0.001) and glutathione reductase (GR) activity (r = 0.352, p = 0.030) and inversely correlated with erythrocyte protein carbonyls (PC) levels (r = - 0.325; p = 0.046). Knee extensors eccentric peak torque was positively correlated with GR activity (r = 0.355; p = 0.031) while, one-repetition maximum in back squat exercise was positively correlated with erythrocyte GSH/GSSG ratio (r = 0.401; p = 0.014) and inversely correlated with erythrocyte GSSG and PC (r = - 0.441, p = 0.006; r = - 0.413, p = 0.011 respectively). Glutathione peroxidase (GPx) activity was positively correlated with step count (r = 0.520; p < 0.001), light (r = 0.406; p = 0.008), moderate (r = 0.417; p = 0.006), moderate-to-vigorous (r = 0.475; p = 0.001), vigorous (r = 0.352; p = 0.022) and very vigorous (r = 0.326; p = 0.035) PA. Muscle GSSG inversely correlated with light PA (r = - 0.353; p = 0.022).

CONCLUSION

These results indicate that dietary cysteine intake may be a critical element for the regulation of glutathione metabolism and redox status in two different tissues pinpointing the independent significance of cysteine for optimal redox regulation. Musculoskeletal fitness and PA levels may be predictors of skeletal muscle, but not erythrocyte, antioxidant capacity.

TRIAL REGISTRATION

Registry: ClinicalTrials.gov, identifier: NCT03711838, date of registration: October 19, 2018.

Effect of Tribulus terrestris L. supplementation on Exercise-Induced Oxidative Stress and Delayed Onset Muscle Soreness Markers: A Pilot Study

Tribulus terrestris L. contains compounds with antioxidant and anti-inflammatory properties, but its effects on exercise-induced oxidative stress and inflammatory responses are unclear. The aim of this study was to examine whether Tribulus terrestris L. supplementation can attenuate oxidative stress and inflammatory responses to acute aerobic exercise and improve DOMS. In a randomized, double-blind, crossover design study, thirteen healthy men received either a daily supplement of Tribulus terrestris L. or a placebo for 4 weeks (2-week wash-out period between trials). Before and after the supplementation periods, participants performed an exercise test to exhaustion (75% VO2max). DOMS, thigh girth, and knee joint range of motion (KJRM) were assessed before and after the exercise (2, 24, and 48 h). Blood samples were analyzed for reduced (GSH) and oxidized (GSSG) glutathione, GSH/GSSG ratio, protein carbonyls, total antioxidant capacity, creatine kinase activity, white blood cell count, and TBARS. Acute exercise to exhaustion induced inflammatory responses and changed the blood redox status in both Tribulus and Placebo groups (p < 0.050). Tribulus terrestris L. improved GSH fall (p = 0.005), GSSG rise (p = 0.001) and maintained a higher level of GSH/GSSG ratio at the 2 h point (p = 0.034). TBARS were lowered, protein carbonyls, creatine kinase activity, and white blood cell count elevation diminished significantly (p < 0.050). Tribulus terrestris L. administration did not affect DOMS, thigh girth, or KJRM (p > 0.050). 4-weeks of Tribulus terrestris L. supplementation effectively attenuates oxidative stress responses but cannot improve DOMS.

The effects of N-acetylcysteine on recovery biomarkers: A systematic review and meta-analysis of controlled trials

N-acetylcysteine (NAC) is one of the antioxidant supplements which is thought to improve recovery. Existing studies regarding NAC and recovery presented conflicting results. This systematic review and meta-analysis evaluated the existing trials and determined the efficacy of acute and chronic NAC administration on recovery biomarkers. PubMed, Web of Science, and Scopus were searched up to July 2021. The random effects or fixed effects model was applied in the meta-analysis. Sensitivity and subgroup analyses were performed. In case of the presence of publication bias, standard methods were applied. The meta-analysis comprised 37 papers (1,388 participants). All included studies were in English language. Acute NAC administration indicated no significant effects on lactate, pH, VO₂ , and CPK-MB ([SMD = -0.06 mmol/L; 95% CI: -0.40, 0.28; p = .714], [SMD = 0.17; 95% CI: -0.28, 0.62; p = .454], [SMD = -0.11 L/min; 95% CI: -0.63, 0.41; p = .686], and [SMD = -0.19 units/L; 95% CI: -0.62, 0.24; p = .395]). Additionally, no evidence of significant influence of chronic NAC administration on lactate, pH, VO₂ , and CK was revealed ([SMD = 0.01 mmol/L; 95% CI: -0.25, 0.27; p = .950], [SMD = -0.51; 95% CI: -1.73, 0.70; p = .424], [SMD = -0.18 L/min; 95% CI: -0.56, 0.20; p = .361], and [SMD = -0.04 units/L; 95% CI: -0.36, 0.29; p = .821]). No considerable effect of NAC on recovery was found. PRACTICAL APPLICATIONS: Previous studies on the influence of NAC administration on recovery biomarkers have presented conflicting results. This systematic review and meta-analysis offers a broad range of detailed information on the influence of chronic and acute NAC supplementation outcomes regarding recovery biomarkers. Overall, the results support that NAC supplementation may not be effective in improving recovery biomarkers. However, subgroup analyses based on NAC dosage indicated the meaningful effect of NAC on CK-MB at the dosage of ≥100 mg/kg.

Exercise Training Induces a Shift in Extracellular Redox Status with Alterations in the Pulmonary and Systemic Redox Landscape in Asthma

Redox dysregulation and oxidative stress have been implicated in asthma pathogenesis. Exercise interventions improve symptoms and reduce inflammation in asthma patients, but the underlying mechanisms remain unclear. We hypothesized that a personalised exercise intervention would improve asthma control by reducing lung inflammation through modulation of local and systemic reactive species interactions, thereby increasing antioxidant capacity. We combined deep redox metabolomic profiling with clinical assessment in an exploratory cohort of six female patients with symptomatic asthma and studied their responses to a metabolically targeted exercise intervention over 12 weeks. Plasma antioxidant capacity and circulating nitrite levels increased following the intervention (p = 0.028) and lowered the ratio of reduced to oxidised glutathione (p = 0.029); this was accompanied by improvements in physical fitness (p = 0.046), symptoms scores (p = 0.020), quality of life (p = 0.046), lung function (p = 0.028), airway hyperreactivity (p = 0.043), and eosinophilic inflammation (p = 0.007). Increased physical fitness correlated with improved plasma antioxidant capacity (p = 0.019), peak oxygen uptake and nitrite changes (p = 0.005), the latter also associated with reductions in peripheral blood eosinophil counts (p = 0.038). Thus, increases in “redox resilience” may underpin the clinical benefits of exercise in asthma. An improved understanding of exercise-induced alterations in redox regulation offers opportunities for greater treatment personalisation and identification of new treatment targets.

Hydrogen-rich water suppresses the reduction in blood total antioxidant capacity induced by 3 consecutive days of severe exercise in physically active males

Repeated sprint exercise can interfere with intramuscular redox balance and cause systemic oxidative stress and muscle damage. There is growing evidence that molecular hydrogen counteracts oxidative and/or inflammatory responses. Therefore, we investigated the effects of molecular hydrogen-rich water (HW) on muscle performance and oxidative stress markers induced by strenuous exercise. A single-blind, crossover, randomized controlled trial has been designed. Eight male volunteers completed two 3-day consecutive exercise tests under two conditions: HW and placebo water (PW). The exercise test included a countermovement jump, maximal voluntary isometric contraction of knee extensors, and sprint cycling. The sprint cycling exercise was comprised three repetitions of 10-second maximal pedaling against a resistance of 7.5% body mass and 110-second active rest (no-load pedaling). Before and after the exercise test, participants drank the 500 mL of HW (5.14 ± 0.03 ppm in H₂ concentration) or PW (0.00 ± 0.00 ppm). At 7 hours before the first exercise test (Day 1), as baseline, and 16 hours after the exercise test on each day, blood samples were obtained. Exercise performances in both conditions were not significantly different over 3 consecutive days. In PW trial, relative changes in biological antioxidant potential/diacron-reactive oxygen metabolites, as an index of systemic antioxidant potential, from baseline gradually decreased as the day passed. However, HW suppressed the reduction in biological antioxidant potential/diacron-reactive oxygen metabolites observed in PW. Drinking HW contributed to the maintenance of the redox status during consecutive days of strenuous exercise and might help prevent accumulative muscular fatigue. The study was approved by the Human Research Ethics Committee of the University of Yamanashi, Japan (approval No. H26-008) on December 17, 2014.

How N-Acetylcysteine Supplementation Affects Redox Regulation, Especially at Mitohormesis and Sarcohormesis Level: Current Perspective

Exercise frequently alters the metabolic processes of oxidative metabolism in athletes, including exposure to extreme reactive oxygen species impairing exercise performance. Therefore, both researchers and athletes have been consistently investigating the possible strategies to improve metabolic adaptations to exercise-induced oxidative stress. N-acetylcysteine (NAC) has been applied as a therapeutic agent in treating many diseases in humans due to its precursory role in the production of hepatic glutathione, a natural antioxidant. Several studies have investigated NAC’s possible therapeutic role in oxidative metabolism and adaptive response to exercise in the athletic population. However, still conflicting questions regarding NAC supplementation need to be clarified. This narrative review aims to re-evaluate the metabolic effects of NAC on exercise-induced oxidative stress and adaptive response developed by athletes against the exercise, especially mitohormetic and sarcohormetic response.

Can Exercise-Induced Muscle Damage Be a Good Model for the Investigation of the Anti-Inflammatory Properties of Diet in Humans?

Subclinical, low-grade, inflammation is one of the main pathophysiological mechanisms underlying the majority of chronic and non-communicable diseases. Several methodological approaches have been applied for the assessment of the anti-inflammatory properties of nutrition, however, their impact in human body remains uncertain, because of the fact that the majority of the studies reporting anti-inflammatory effect of dietary patterns, have been performed under laboratory settings and/or in animal models. Thus, the extrapolation of these results to humans is risky. It is therefore obvious that the development of an inflammatory model in humans, by which we could induce inflammatory responses to humans in a regulated, specific, and non-harmful way, could greatly facilitate the estimation of the anti-inflammatory properties of diet in a more physiological way and mechanistically relevant way. We believe that exercise-induced muscle damage (EIMD) could serve as such a model, either in studies investigating the homeostatic responses of individuals under inflammatory stimuli or for the estimation of the anti-inflammatory or pro-inflammatory potential of dietary patterns, foods, supplements, nutrients, or phytochemicals. Thus, in this review we discuss the possibility of exercise-induced muscle damage being an inflammation model suitable for the assessment of the anti-inflammatory properties of diet in humans.

Technical match actions and plasma stress markers in elite female football players during an official FIFA Tournament

This study analyzed the impact of performing four consecutive football matches separated by 48-72 hours during a FIFA tournament on physical load, technical performance and plasma markers of redox state, muscle damage and inflammation in elite female players. Forty-eight players from three national teams were evaluated at seven time points: before (baseline) and throughout the tournament (after each match and before two training sessions). Only data from players who played all matches were included in the analyses (N = 13). The players were divided into high-rank (N = 6) and low-rank (N = 7) team players according to FIFA standards. Plasma creatine kinase (CK), C-reactive protein (CRP), total antioxidant status (TAS), and uric acid (UA) were analyzed at the selected time points. Technical performance and physical load were also quantified according to team rank. Players from low-rank teams played significantly more time than high-rank players (85 ± 10 vs 67 ± 15 minutes; P = .02; d = 1.51). Low-rank team players presented higher values in technical performance actions than the high-rank team players, but most of the differences were explained by the longer match time played. UA content differed across the matches, increasing from baseline (F_(4,40)  = 3.90; P = .01) and more in the high-rank team players (F_(1,10)  = 20.46; P = .001), while CRP only differed across the matches (F_(4,36)  = 2.66; P = .05), also increasing from baseline. A large time effect was shown for UA only in the high-rank players (η² _p  = 0.50; P = .02). Four consecutive matches did not result in considerable alterations in plasma stress markers, physical load, and technical performance in elite female football players from distinct rank levels.

Redox-dependent regulation of satellite cells following aseptic muscle trauma: Implications for sports performance and nutrition

Skeletal muscle satellite cells (SCs) are indispensable for tissue regeneration, remodeling and growth. Following myotrauma, SCs are activated, and assist in tissue repair. Exercise-induced muscle damage (EIMD) is characterized by a pronounced inflammatory response and the production of reactive oxygen species (ROS). Experimental evidence suggests that SCs kinetics (the propagation from a quiescent to an activated/proliferative state) following EIMD is redox-dependent and interconnected with changes in the SCs microenvironment (niche). Animal studies have shown that following aseptic myotrauma, antioxidant and/or anti-inflammatory supplementation leads to an improved recovery and skeletal muscle regeneration through enhanced SCs kinetics, suggesting a redox-dependent molecular mechanism. Although evidence suggests that antioxidant/anti-inflammatory compounds may prevent performance deterioration and enhance recovery, there is lack of information regarding the redox-dependent regulation of SCs responses following EIMD in humans. In this review, SCs kinetics following aseptic myotrauma, as well as the intrinsic redox-sensitive molecular mechanisms responsible for SCs responses are discussed. The role of redox status on SCs function should be further investigated in the future with human clinical trials in an attempt to elucidate the molecular pathways responsible for muscle recovery and provide information for potential nutritional strategies aiming at performance recovery.

The effects of N-Acetylcysteine on serum level of inflammatory biomarkers in adults. Findings from a systematic review and meta-analysis of randomized clinical trials

PURPOSE

Randomized Clinical Trials (RCTs) have provided varied and conflicting findings regarding the effect of N-acetylcysteine (NAC) on inflammatory biomarkers. This study was conducted to review existing literature to determine whether NAC supplementation can affect inflammatory biomarkers in adults.

METHODS

Bibliographic databases of Scopus, and PubMed were used for relevant papers published until October 2019. Results were reported as weighted mean differences (WMD) with 95% confidence intervals (CI) using multi-level models. Cochrane's Q and I-squared (I2) tests were used to determine heterogeneity among studies.

RESULTS

Twenty-four RCTs which include 1057 sample size were entered to analysis. NAC doses and intervention duration ranged from 400 to 2000 mg/d, and 1 to 80 weeks, respectively. Oral supplementation of NAC reduced serum level of C-reactive protein (CRP) [WMD: -0.61 mg/L, 95% CI: -1.18 to -0.03, P = 0.039, I2 = 79.6%], and interleukin-6 (IL-6) [WMD: -0.43 pg/mL, 95% CI: -0.69 to -0.17, P = 0.001, I2 = 89.3%]. However, the effect of oral NAC supplementation on other inflammatory biomarkers was nonsignificant. Dose-response investigation showed a non-linear association between oral NAC supplementation with CRP.

CONCLUSION

Oral NAC supplementation reduced serum level of CRP and IL-6, but did not affect other inflammatory biomarkers. Nevertheless, more RCTs seems to be required to explore how NAC in different dosage and different routes of administration can affect inflammatory biomarkers.

Impact of hydrogen-rich gas mixture inhalation through nasal cannula during post-exercise recovery period on subsequent oxidative stress, muscle damage, and exercise performances in men

Molecular hydrogen has been suggested to have a cytoprotective effect on the whole body and to enhance exercise performances. However, the effect of hydrogen-rich gas mixture (HG) inhalation on physiological responses has been poorly investigated. We examined the impact of acute HG inhalation on subsequent oxidative stress, muscle damage, and exercise performances during the recovery period after a strenuous exercise. This is a two-trial, double-blind, crossover, repeated measures study. Eight physically active male volunteers inhaled HG (estimated fraction of inspired oxygen and hydrogen were 21.57 and 4.08% at most, respectively) or normal gas (placebo, ambient air 400 m above sea level) during a 60-minute recovery phase after oxidative stress-inducing exercise) completion comprising 30-minute treadmill running at an intensity corresponding to 75% of maximal oxygen uptake and squat jumps (5 sets × 10 repetitions). Before oxidative stress-inducing exercise and 10 minutes after the post-exercise gas inhalation, blood and urine samples were obtained and exercise performances (jumping ability; pedaling power output; muscle strength) were evaluated. Post-exercise HG inhalation attenuated the increase in urinary 8-hydroxydeoxyguanosine excretion rate (P < 0.05), a DNA oxidation marker, and the reduction in the countermovement jump height (P < 0.05), compared with Placebo inhalation. Other exercise performances and blood oxidative stress and muscle damage markers did not differ between HG and Placebo inhalation. Moreover, the increase in urinary 8-hydroxydeoxyguanosine excretion rate was significantly associated with countermovement jump performance reduction (r = -0.78, P < 0.01). These findings suggested that HG inhalation during post-exercise recovery period might improve exercise performance via reducing systemic oxidative damage. The study was approved by the Human Research Ethics Committee of the University of Yamanashi (approval No. H29-006) on June 28, 2017.

Redox Changes in Amateur Race Car Drivers Before and After Racing

Despite the unique opportunity race car driving provides to study exercise in extreme conditions, the sport of racing is under-represented. A better understanding of how racing changes physiological measures combined with driver demographics may help reduce driver risks and expand the field of driver science. This study charted the changes in heart rate, body temperature, blood pressure, static oxidation reduction potential (sORP), and antioxidant capacity in drivers before and after racing (n=23). The interaction between racing and driver characteristics on physiological variables were evaluated. Heart rate, body temperature, and sORP were elevated after racing (P<0.05). Age, cockpit temperature, experience, and speed did not correlate with physiological or oxidative measures (P>0.05). Elevated post-race sORP values were associated with higher pre-race systolic blood pressure and lower antioxidant capacity (P<0.05). We conclude that racing alters the redox response in drivers and that drivers' pre-race systolic blood pressure and antioxidant capacity can further alter it. A better understanding of the physical and oxidative changes which result from racing may help minimize the unique risks.

Preliminary evidence of reductive stress in human cytotoxic T cells following exercise

This study investigated immunophenotypic differences in intracellular thiol redox state of peripheral blood mononuclear cells (PBMCs) isolated from trained [ n = 9, means ± SD: age 28 ± 5 yr; (body mass index) BMI 23.2 ± 2.6 kg/m2; V̇o2max (maximal oxygen intake)56.9 ± 6.1 ml·kg−1·min−1] and recreationally active (RA, n = 11, means ± SD: age 27 ± 6 yr; BMI 24.2 ± 3.7 kg/m2; V̇o2max 45.1 ± 6.4 ml·kg−1·min−1) participants before and after a maximal aerobic exercise tolerance test. Blood samples were taken before (Pre), during (sample acquired at 70% maximum heart rate), immediately after (Post + 0), and 15 min postexercise (Post + 15). PBMCs were isolated, and reduced thiol analysis [fluorescein-5 maleimide (F5M)] by immunophenotype [cluster of differentiation (CD)3+, CD4+, and CD8+] was performed using flow cytometry. A significant increase in cellular F5M fluorescence was observed in CD3+ T cells at Post + 0, with changes driven to a greater extent by CD8+ T cells (fold change in both groups CD4: +2.3, CD8: +2.8; P < 0.05). Further analysis revealed a population of highly reduced CD8+ T cells (CD8+T-reduced+) that significantly increased from Pre to Post + 0 in RA participants only (RA: +272 cell/µl, P < 0.05). To understand these results further, CD8+T-reduced+ and CD8+T-reduced− cells were analyzed for immunophenotype in response to the same exercise protocol ( n = 6, means ± SD: age 24 ± 5 yr; BMI 25.7 ± 4.1 kg·m−2; V̇o2max 41.33 ± 7.63 ml·kg−1·min−1). CD8+T-reduced+ had significantly less lymphoid homing potential (chemokine receptor type 7) Post + 0 compared with Pre. This study is the first, to our knowledge, to demonstrate that lymphocyte populations become more reductive in response to acute exercise.

NEW & NOTEWORTHY The study presented provides the first evidence to suggest that cytotoxic T cells become transiently reductive in healthy individuals following a single bout of cycling. Detection of these cells was enabled via the use of a flow cytometric assay that incorporates the thiol reactive probe fluorescein-5 maleimide. Using this method, transient reductive stress in viable T cells is permissible and provides the basis for further research in the area of exercise immunology.

Strength Training Session Induces Important Changes on Physiological, Immunological, and Inflammatory Biomarkers

Strength exercise is a strategy applied in sports and physical training processes. It may induce skeletal muscle hypertrophy. The hypertrophy is dependent on the eccentric muscle actions and on the inflammatory response. Here, we evaluate the physiological, immunological, and inflammatory responses induced by a session of strength training with a focus on predominance of the eccentric muscle actions. Twenty volunteers were separated into two groups: the untrained group (UTG) and the trained group (TG). Both groups hold 4 sets of leg press, knee extensor, and leg curl at 65% of personal one-repetition maximum (1RM), 90 s of recovery, and 2^″conc/3^″eccen of duration of execution in each repetition. Blood samples were collected immediately before and after, 2 hours after, and 24 h after the end of the exercise session. The single session of strength training elevated the heart rate (HR), rating of perceived exertion (RPE), visual analog scale (VAS), and lactate blood level in UTG and TG. Creatine kinase (CK) levels were higher at 2 and 24 h after the end of the exercise in UTG and, in TG, only at 24 h. The number of white blood cells (WBC) and neutrophils increased in UTG and TG, post and 2 h after exercise. Lymphocytes increased postexercise but reduced 2 h after exercise in both groups, while the number of monocytes increased only immediately after the exercise session in UTG and TG. The strength training session elevated the levels of apelin and fatty acid-binding proteins-3 (FABP3) in both groups and brain-derived neurotrophic factor (BDNF) in TG. The single exercise session was capable of inducing elevated HR, RPE, lactate level, and CK levels. This protocol changed the count/total number of circulating immune cells in both groups (UTG and TG) and also increased the level of plasmatic apelin, BDNF, and FLTS1 only in TG and FABP3 myokines in both groups.

Post-Game High Protein Intake May Improve Recovery of Football-Specific Performance during a Congested Game Fixture: Results from the PRO-FOOTBALL Study

The effects of protein supplementation on performance recovery and inflammatory responses during a simulated one-week in-season microcycle with two games (G1, G2) performed three days apart were examined. Twenty football players participated in two trials, receiving either milk protein concentrate (1.15 and 0.26 g/kg on game and training days, respectively) (PRO) or an energy-matched placebo (1.37 and 0.31 g/kg of carbohydrate on game and training days, respectively) (PLA) according to a randomized, repeated-measures, crossover, double-blind design. Each trial included two games and four daily practices. Speed, jump height, isokinetic peak torque, and muscle soreness of knee flexors (KF) and extensors (KE) were measured before G1 and daily thereafter for six days. Blood was drawn before G1 and daily thereafter. Football-specific locomotor activity and heart rate were monitored using GPS technology during games and practices. The two games resulted in reduced speed (by 3–17%), strength of knee flexors (by 12–23%), and jumping performance (by 3–10%) throughout recovery, in both trials. Average heart rate and total distance covered during games remained unchanged in PRO but not in PLA. Moreover, PRO resulted in a change of smaller magnitude in high-intensity running at the end of G2 (75–90 min vs. 0–15 min) compared to PLA (P = 0.012). KE concentric strength demonstrated a more prolonged decline in PLA (days 1 and 2 after G1, P = 0.014–0.018; days 1, 2 and 3 after G2, P = 0.016–0.037) compared to PRO (days 1 after G1, P = 0.013; days 1 and 2 after G2, P = 0.014–0.033) following both games. KF eccentric strength decreased throughout recovery after G1 (PLA: P=0.001–0.047—PRO: P =0.004–0.22) in both trials, whereas after G2 it declined throughout recovery in PLA (P = 0.000–0.013) but only during the first two days (P = 0.000–0.014) in PRO. No treatment effect was observed for delayed onset of muscle soreness, leukocyte counts, and creatine kinase activity. PRO resulted in a faster recovery of protein and lipid peroxidation markers after both games. Reduced glutathione demonstrated a more short-lived reduction after G2 in PRO compared to PLA. In summary, these results provide evidence that protein feeding may more efficiently restore football-specific performance and strength and provide antioxidant protection during a congested game fixture.

Acute Strenuous Exercise Induces an Imbalance on Histone H4 Acetylation/Histone Deacetylase 2 and Increases the Proinflammatory Profile of PBMC of Obese Individuals

This study evaluated the response of global histone H4 acetylation (H4ac), histone deacetylase 2 (HDAC2) activity, as well as the production of proinflammatory cytokines and monocyte phenotypes of lean and obese males after exercise. Ten lean and ten obese sedentary men were submitted to one session of strenuous exercise, and peripheral blood mononuclear cells (PBMC) were stimulated in vitro with lipopolysaccharide (LPS). Global H4ac levels, HDAC2 activity in PBMC, and IL-6, IL-8, and TNF-α production were analyzed. Monocyte phenotype was determined in accordance with the expression of CD14 and CD16. At rest, obese individuals presented higher frequency of proinflammatory CD14⁺CD16⁺ monocytes. LPS induced a significant augment in global H4ac and in the production of IL-6, IL-8, and TNF-α mainly in obese individuals. After exercise, the increased production of IL-8 and TNF-α and peripheral frequency of CD14⁺CD16⁺ were observed in both groups. In addition, exercise also induced a significant hyperacetylation of histone H4 and decreased HDAC2 activity in both nonstimulated and LPS-stimulated PBMC of obese individuals. Our data indicate that the obesity impacts on H4ac levels and that strenuous exercise leads to an enhanced chronic low-grade inflammation profile in obesity via an imbalance on H4ac/HDAC2.

Iron Supplementation Effects on Redox Status following Aseptic Skeletal Muscle Trauma in Adults and Children

Exercise-induced skeletal muscle microtrauma is characterized by loss of muscle cell integrity, marked aseptic inflammatory response, and oxidative stress. We examined if iron supplementation would alter redox status after eccentric exercise. In a randomized, double blind crossover study, that was conducted in two cycles, healthy adults (n = 14) and children (n = 11) received daily either 37 mg of elemental iron or placebo for 3 weeks prior to and up to 72 h after an acute eccentric exercise bout. Blood was drawn at baseline, before exercise, and 72 h after exercise for the assessment of iron status, creatine kinase activity (CK), and redox status. Iron supplementation at rest increased iron concentration and transferrin saturation (p < 0.01). In adults, CK activity increased at 72 h after exercise, while no changes occurred in children. Iron supplementation increased TBARS at 72 h after exercise in both adults and children; no changes occurred under placebo condition. Eccentric exercise decreased bilirubin concentration at 72 h in all groups. Iron supplementation can alter redox responses after muscle-damaging exercise in both adults and children. This could be of great importance not only for healthy exercising individuals, but also in clinical conditions which are characterized by skeletal muscle injury and inflammation, yet iron supplementation is crucial for maintaining iron homeostasis. This study was registered at Clinicaltrials.gov Identifier: NCT02374619.

Exercise-Induced Oxidative Stress Responses in the Pediatric Population

Adults demonstrate an upregulation of their pro- and anti-oxidant mechanisms in response to acute exercise while systematic exercise training enhances their antioxidant capacity, thereby leading to a reduced generation of free radicals both at rest and in response to exercise stress. However, less information exists regarding oxidative stress responses and the underlying mechanisms in the pediatric population. Evidence suggests that exercise-induced redox perturbations may be valuable in order to monitor exercise-induced inflammatory responses and as such training overload in children and adolescents as well as monitor optimal growth and development. The purpose of this review was to provide an update on oxidative stress responses to acute and chronic exercise in youth. It has been documented that acute exercise induces age-specific transient alterations in both oxidant and antioxidant markers in children and adolescents. However, these responses seem to be affected by factors such as training phase, training load, fitness level, mode of exercise etc. In relation to chronic adaptation, the role of training on oxidative stress adaptation has not been adequately investigated. The two studies performed so far indicate that children and adolescents exhibit positive adaptations of their antioxidant system, as adults do. More studies are needed in order to shed light on oxidative stress and antioxidant responses, following acute exercise and training adaptations in youth. Available evidence suggests that small amounts of oxidative stress may be necessary for growth whereas the transition to adolescence from childhood may promote maturation of pro- and anti-oxidant mechanisms. Available evidence also suggests that obesity may negatively affect basal and exercise-related antioxidant responses in the peripubertal period during pre- and early-puberty.

Aberrant control of NF-κB in cancer permits transcriptional and phenotypic plasticity, to curtail dependence on host tissue: molecular mode

The role of the transcription factor NF-κB in shaping the cancer microenvironment is becoming increasingly clear. Inflammation alters the activity of enzymes that modulate NF-κB function, and causes extensive changes in genomic chromatin that ultimately drastically alter cell-specific gene expression. NF-κB regulates the expression of cytokines and adhesion factors that control interactions among adjacent cells. As such, NF-κB fine tunes tissue cellular composition, as well as tissues' interactions with the immune system. Therefore, NF-κB changes the cell response to hormones and to contact with neighboring cells. Activating NF-κB confers transcriptional and phenotypic plasticity to a cell and thereby enables profound local changes in tissue function and composition. Research suggests that the regulation of NF-κB target genes is specifically altered in cancer. Such alterations occur not only due to mutations of NF-κB regulatory proteins, but also because of changes in the activity of specific proteostatic modules and metabolic pathways. This article describes the molecular mode of NF-κB regulation with a few characteristic examples of target genes.