Consensus Statement Immunonutrition and Exercise.

In this consensus statement on immunonutrition and exercise, a panel of knowledgeable contributors from across the globe provides a consensus of updated science, including the background, the aspects for which a consensus actually exists, the controversies and, when possible, suggested directions for future research

Global proteome changes in the rat diaphragm induced by endurance exercise training

Mechanical ventilation (MV) is a life-saving intervention for many critically ill patients. Unfor- tunately, prolonged MV results in the rapid development of diaphragmatic atrophy and weakness. Importantly, endurance exercise training results in a diaphragmatic phenotype that is protected against ventilator-induced diaphragmatic atrophy and weakness. The mechanisms responsible for this exercise-induced protection against ventilator-induced dia- phragmatic atrophy remain unknown. Therefore, to investigate exercise-induced changes in diaphragm muscle proteins, we compared the diaphragmatic proteome from sedentary and exercise-trained rats. Specifically, using label-free liquid chromatography-mass spectrome- try, we performed a proteomics analysis of both soluble proteins and mitochondrial proteins isolated from diaphragm muscle. The total number of diaphragm proteins profiled in the sol- uble protein fraction and mitochondrial protein fraction were 813 and 732, respectively. Endurance exercise training significantly (P<0.05, FDR <10%) altered the abundance of 70 proteins in the soluble diaphragm proteome and 25 proteins of the mitochondrial proteome. In particular, key cytoprotective proteins that increased in relative abundance following exer- cise training included mitochondrial fission process 1 (Mtfp1; MTP18), 3-mercaptopyruvate sulfurtransferase (3MPST), microsomal glutathione S-transferase 3 (Mgst3; GST-III), and heat shock protein 70 kDa protein 1A/1B (HSP70). While these proteins are known to be cytoprotective in several cell types, the cyto-protective roles of these proteins have yet to be fully elucidated in diaphragm muscle fibers. Based upon these important findings, future experiments can now determine which of these diaphragmatic proteins are sufficient and/or required to promote exercise-induced protection against inactivity-induced muscle atrophy

Increased Short-Term Variability of the QT Interval in Professional Soccer Players: Possible Implications for Arrhythmia Prediction

BACKGROUND: Sudden cardiac death in competitive athletes is rare but it is significantly more frequent than in the normal population. The exact cause is seldom established and is mostly attributed to ventricular fibrillation. Myocardial hypertrophy and slow heart rate, both characteristic changes in top athletes in response to physical conditioning, could be associated with increased propensity for ventricular arrhythmias. We investigated conventional ECG parameters and temporal short-term beat-to-beat variability of repolarization (STV(QT)), a presumptive novel parameter for arrhythmia prediction, in professional soccer players. METHODS: Five-minute 12-lead electrocardiograms were recorded from professional soccer players (n = 76, all males, age 22.0±0.61 years) and age-matched healthy volunteers who do not participate in competitive sports (n = 76, all males, age 22.0±0.54 years). The ECGs were digitized and evaluated off-line. The temporal instability of beat-to-beat heart rate and repolarization were characterized by the calculation of short-term variability of the RR and QT intervals. RESULTS: Heart rate was significantly lower in professional soccer players at rest (61±1.2 vs. 72±1.5/min in controls). The QT interval was prolonged in players at rest (419±3.1 vs. 390±3.6 in controls, p<0.001). QTc was significantly longer in players compared to controls calculated with Fridericia and Hodges correction formulas. Importantly, STV(QT) was significantly higher in players both at rest and immediately after the game compared to controls (4.8±0.14 and 4.3±0.14 vs. 3.5±0.10 ms, both p<0.001, respectively). CONCLUSIONS: STV(QT) is significantly higher in professional soccer players compared to age-matched controls, however, further studies are needed to relate this finding to increased arrhythmia propensity in this population

HIGH-INTENSITY INTERVAL TRAINING FOLLOWING SEVEN WEEKS OF RESISTANCE TRAINING ALTERS MUSCLE CALPAIN AND AUTOPHAGY MARKERS

Daniel L. Plotkin1, J. Max Michel1, Joshua S. Godwin1, Paulo H.C. Mesquita1, Bradley A. Ruple1, Mason C. McIntosh1, Cleiton A. Libardi2, Andreas N. Kavazis1, Michael D. Roberts1,3. 1Auburn University, Auburn, AL. 2Federal University of Sao Carlos, Sao Carlos. 3Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL. BACKGROUND: While the dynamics of muscle protein balance have been explored in the context of many exercise modalities, they have not been studied in a resistance training followed by endurance training (ET) paradigm. Our laboratory recently determined that seven weeks of resistance training (RT) increases vastus lateralis (VL) muscle thickness, and seven weeks of treadmill high-intensity interval training (HIIT) following the RT period reduces VL muscle thickness. Thus, the purpose of this study was to examine calpain and autophagy activity markers after the 7-week RT and HIIT periods. METHODS: Vastus lateralis biopsies and muscle thickness (MT) measures were collected from 11 untrained college-aged males at baseline (PRE), after 7 weeks of RT (MID) and after a subsequent 7 weeks of HIIT (POST). Proteins associated with autophagy and calpain activities were assessed via immunoblotting, and calpain activity was assessed via a commercially available plate-based assay. Data were checked for normality using Shapiro-Wilk tests and analyzed via one-way ANOVAs. RESULTS: Tukey’s Multiple comparisons test showed a significant increase in MT from PRE to MID [2.3 mm, CI95% = (1.1 mm, 3.5 mm), p= 0.001], a significant decrease from MID to POST [1.2 mm, CI95% = (0.30 mm, 2.1 mm), p= 0.012],and a non-significant increase from PRE to POST [1.1 mm, CI95% = (2.1 mm, 2.9 mm), p= 0.213]. Microtubule-associated proteins 1A/1B light chain 3B (LC3 II/I), phosphorylated AMP-kinase (p-AMPKα, Thr172) / pan-AMPKα, and calpain-1 protein abundance did not reach overall ANOVA significance with respective p-values of 0.854, 0.330, 0.365. Phosphorylated-Unc-51 like autophagy activating kinase 1 (p-ULK, Ser555) / pan-ULK protein abundance was not significant between time points. Beclin-1 protein abundance increased from PRE to MID (p= 0.012) and PRE to POST (p = 0.005). Calpain-2 increased from PRE to MID (p = 0.001) and PRE to POST (p = 0.003). Finally, calpain-activity normalized to Calpain-1/2 protein content decreased from PRE to MID (p = 0.001), albeit with no significant differences from PRE to POST and MID to POST. CONCLUSION: These data suggest that an elevation in calpain activity markers (rather than autophagy markers) during seven weeks of HIIT may have been partially responsible for mid-thigh muscle size decreases following a seven-week period of RT

THE UBIQUITIN-PROTEASOME SYSTEM: IMPLICATED IN HIIT INDUCED MUSCLE ATROPHY FOLLOWING SEVEN WEEKS OF RESISTANCE TRAINING

J. Max Michel1, Daniel L. Plotkin1, Joshua S. Godwin1, Paulo H.C. Mesquita1, Bradley A. Ruple1, Mason C. McIntosh1, Cleiton A. Libardi2, Andreas N. Kavazis1, Michael D. Roberts3,1. 1Auburn University, Auburn, AL. 2Federal University of Sao Carlos, Sao Carlos, Brazil. 3Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL. BACKGROUND: Skeletal muscle is a highly plastic tissue that uniquely responds to different external stimuli. While resistance training (RT) induces skeletal muscle hypertrophy, the effects of high-intensity interval training (HIIT) are less clear, with certain evidence indicating mild hypertrophy and other evidence suggesting no change in measurable outcomes. Our laboratory recently observed an increase in vastus lateralis thickness after seven weeks of RT (2 d/wk), with values returning to pre-training levels following seven weeks of treadmill HIIT (3 d/wk). Given that proteolytic mechanisms were not previously investigated, the purpose of this study was to examine the effects of the aforementioned exercise paradigm on markers of the ubiquitin-proteasome system (UPS). METHODS: Vastus lateralis biopsies were collected from 11 untrained college-aged males at baseline (PRE), after seven weeks of RT (MID) and after a subsequent seven weeks of HIIT (POST). Tissue was analyzed for atrogene mRNA expression, proteins associated with the UPS, and 20S proteasome activity. Data were checked for normality using Shapiro-Wilk tests and analyzed via one-way ANOVAs. RESULTS: Muscle really interesting new gene (RING) finger 1 (MuRF1), Atrogin-1, and forkhead box O3a (FOXO3a) all achieved significance at the overall ANOVA level (p≤0.0129). These mRNAs were all significantly upregulated at POST as compared to both PRE (p≤0.0315), and MID (p≤0.0315). Poly-ubiquitinated proteins achieved overall ANOVA significance (p=0.0185) and trended toward a significant increase at both MID (p=0.0694) and POST (p=0.0529). Protein abundance of the 20S proteasome core demonstrated overall ANOVA significance (p=0.0096) and showed increases at POST as compared to both PRE (p=0.0311) and MID (p=0.0485). Finally, 20S proteasome activity demonstrated overall ANOVA significance (p=0.0031) and showed increases from PRE at both MID (p=0.0011) and POST (p=0.0040). CONCLUSIONS: Markers of the UPS were upregulated at POST at the mRNA, protein, and activity level suggesting that the UPS played a role in the HIIT-induced atrophy that occurred following a prior seven-week RT program

INFLUENCE OF ACUTE SUPPLEMENTATION WITH MITOCHONDRIAL ANTIOXIDANT MITOQ ON VASCULAR FUNCTION IN HEALTHY ADULTS

Zach J. Hutchison, McKenna A. Tharpe, Alex M. Barnett, Braxton A. Linder, Meral N. Culver, Michael D. Brown, FACSM, Andreas N. Kavazis, FACSM, Austin T. Robinson. Auburn University, Auburn, AL. Background: Cardiovascular disease (CVD) is characterized by endothelial dysfunction and heightened oxidative stress. Additionally, there are well documented racial disparities in endothelial function and CVD. MitoQ, a mitochondrial specific antioxidant, improves vascular function in rodents and healthy older adults by scavenging excess reactive oxygen species (ROS). However, the role of MitoQ in attenuating racial disparities in vascular function is unknown. Therefore, as part of an ongoing clinical trial (NCT04334135), we evaluated endothelial function and ROS in healthy adults pre- and post-acute MitoQ (or placebo) supplementation and performed a preliminary racial comparison. Methods: Seventeen participants (eight males, age: 28±10 years, BMI 25±4 kg/m2, BP 110±12/66±6 mmHg, Mean±SD) were randomly assigned to placebo or MitoQ (100-160mg, depending on body mass). Participants reported as White, Black, or biracial based on parental race. Using a cross design, experimental sessions were separated by a ≥72-hour washout period. Measures were performed before and 60 minutes after ingestion of MitoQ or placebo capsules. We assessed brachial blood pressure (oscillometric) and brachial artery flow mediated dilation (FMD) via ultrasound. We placed an intravenous catheter to assess whole blood ROS levels via electronic paramagnetic resonance. To investigate treatment x time interactions, we performed 2-way ANOVA and ANCOVA. Results: Irrespective of treatment, systolic blood pressure decreased with time (p\u3c0.01). We did not find treatment x time interactions for brachial FMD % (pre placebo: 7.1±4% to post placebo: 6.4±4% vs pre MitoQ: 6.0±4% to post MitoQ: 6.9±4%, p=0.61), brachial shear stress area under the curve (AUC) during reactive hyperemia (p=0.30), or brachial FMD normalized to shear AUC (p=0.46). Additionally, there was not a treatment x time interaction for blood ROS (p=0.67). We identified a trend for a treatment x race interaction (p=0.058) for [post-pre] ∆FMD whereby MitoQ resulted in a negative ∆FMD only in White adults. However, when we included pre-treatment FMD as a covariate for ∆FMD, this trend was attenuated (p=0.193). Conclusion: While additional data are needed, our preliminary findings indicate that acute MitoQ supplementation does not influence vascular function or oxidative stress in healthy adults

Crosstalk between autophagy and oxidative stress regulates proteolysis in the diaphragm during mechanical ventilation.

Mechanical ventilation (MV) results in the rapid development of ventilator-induced diaphragm dysfunction (VIDD). While the mechanisms responsible for VIDD are not fully understood, recent data reveal that prolonged MV activates autophagy in the diaphragm, which may occur as a result of increased cellular reactive oxygen species (ROS) production. Therefore, we tested the hypothesis that (1) accelerated autophagy is a key contributor to VIDD; and that (2) oxidative stress is required to increase the expression of autophagy genes in the diaphragm. Our findings reveal that targeted inhibition of autophagy in the rat diaphragm prevented MV-induced muscle atrophy and contractile dysfunction. Attenuation of VIDD in these animals occurred as a result of increased diaphragm concentration of the antioxidant catalase and reduced mitochondrial ROS emission, which corresponded to reductions in the activity of calpain and caspase-3. To determine if increased ROS production is required for the upregulation of autophagy biomarkers in the diaphragm, rats that were administered the mitochondrial-targeted peptide SS-31 during MV. Results from this study demonstrated that mitochondrial ROS production in the diaphragm during MV is required for the increased expression of key autophagy genes (i.e. LC3, Atg7, Atg12, Beclin1 and p62), as well as for increased activity of cathepsin L. Together, these data reveal that autophagy is required for VIDD, and that autophagy inhibition reduces MV-induced diaphragm ROS production and prevents a positive feedback loop whereby increased autophagy is stimulated by oxidative stress, resulting in further increases in ROS and autophagy