Protein intake and amino acid supplementation regulate exercise recovery and performance through the modulation of mTOR, AMPK, FGF21, and immunity

Oyster (Ostrea Plicatula Gmelin) Peptides Improve Exercise Endurance Capacity via Activating AMPK and HO-1

OBJECTIVE

Previous studies have shown that oyster peptides (OPs) have antioxidant and anti-fatigue activities. This study aimed to investigate the effects of OPs on swimming endurance in mice and the underlying mechanisms.

METHODS

The mice were subjected to gavage with OPs and subjected to exercise training. After 14 days, various biochemical indicators in the blood and gastrocnemius muscle of mice were assessed, and real-time PCR was utilized to detect the level of signal pathway regulation by OPs in the gastrocnemius muscle. Molecular docking technology was employed to observe the potential active components in OPs that regulate signal pathways.

RESULTS

In this study, OPs supplementation combined with and without exercise significantly extended swimming time compared to the sedentary group. OPs supplementation with exercise also increased glycogen levels and decreased blood urea nitrogen, lactate dehydrogenase, and lactic acid levels. Additionally, mice in the exercise with OPs group exhibited higher activities of antioxidant enzymes. OPs can upregulate metabolic regulatory factors such as AMP-activated protein kinase, peroxisome proliferator-activated receptor gamma coactivator-1 alpha, peroxisome proliferator-activated receptor delta, and glucose transporter 4, thereby increasing energy supply during exercise. Additionally, OPs enhances the expression of heme oxygenase 1 and superoxide dismutase 2, thereby reducing oxidative stress during physical activity. Molecular docking analyses revealed that peptides found in OPs formed hydrogen bonds with AMPK and HO-1, indicating that they can exert bioactivity by activating target proteins such as AMPK and HO-1.

CONCLUSIONS

OPs supplementation improved energy reserves, modulated energy metabolism pathways, and coordinated antioxidative stress responses, ultimately enhancing swimming endurance. These findings suggest that OPs have the potential to improve exercise levels by promoting metabolism and improving energy utilization efficiency.

Effect of Spirulina Nigrita® Supplementation on Indices of Exercise-Induced Muscle Damage after Eccentric Protocol of Upper Limbs in Apparently Healthy Volunteers

Spirulina is a supplement with antioxidant and anti-inflammatory properties that may enhance performance and recovery after intense exercise. The present study aimed to investigate the effects of Spirulina Nigrita® on physical performance, and recovery markers after intense eccentric exercise in healthy moderately physically active volunteers. In a double-blind crossover design, participants were supplemented either with spirulina (42 mg Kg-1 BW per day) or a placebo for 15 days before conducting an eccentric exercise protocol using the non-dominant arm. A six-week washout period was required between conditions. Performance and mobility markers such as isometric peak torque (PTQ), ligament range of motion (ROM), and perceived muscle discomfort (VAS) were assessed and blood samples (CK, LDH) were obtained at 1, 24, 48, and 72 h post-exercise. No significant differences were noticed between the two conditions on any of the investigated markers, indicating that spirulina supplementation has no positive effect on isometric muscle performance or alleviation of exercise-induced muscle damage (EIMD) symptoms in the specific population.

Effect of a resistance exercise at acute moderate altitude on muscle health biomarkers

The intensification of the stress response during resistance training (RT) under hypoxia conditions could trigger unwanted effects that compromise muscle health and, therefore, the ability of the muscle to adapt to longer training periods. We examined the effect of acute moderate terrestrial hypoxia on metabolic, inflammation, antioxidant capacity and muscle atrophy biomarkers after a single RT session in a young male population. Twenty healthy volunteers allocated to the normoxia (N < 700 m asl) or moderate altitude (HH = 2320 m asl) group participated in this study. Before and throughout the 30 min following the RT session (3 × 10 reps, 90 s rest, 70% 1RM), venous blood samples were taken and analysed for circulating calcium, inorganic phosphate, cytokines (IL-6, IL-10 and TNF-α), total antioxidant capacity (TAC) and myostatin. Main results displayed a marked metabolic stress response after the RT in both conditions. A large to very large proportional increase in the adjusted to pre-exercise change of inflammatory and anti-inflammatory markers favoured HH (serum TNF-α [ES = 1.10; p = 0.024] and IL-10 [ES = 1.31; p = 0.009]). The exercise produced a similar moderate increment of myostatin in both groups, followed by a moderate non-significant reduction in HH throughout the recovery (ES =  - 0.72; p = 0.21). The RT slightly increased the antioxidant response regardless of the environmental condition. These results revealed no clear impact of RT under acute hypoxia on the metabolic, TAC and muscle atrophy biomarkers. However, a coordinated pro/anti-inflammatory response balances the potentiated effect of RT on systemic inflammation.

Fibroblast Growth Factor 21: A Fascinating Perspective on the Regulation of Muscle Metabolism

Fibroblast growth factor 21 (FGF21) plays a vital role in normal eukaryotic organism development and homeostatic metabolism under the influence of internal and external factors such as endogenous hormone changes and exogenous stimuli. Over the last few decades, comprehensive studies have revealed the key role of FGF21 in regulating many fundamental metabolic pathways, including the muscle stress response, insulin signaling transmission, and muscle development. By coordinating these metabolic pathways, FGF21 is thought to contribute to acclimating to a stressful environment and the subsequent recovery of cell and tissue homeostasis. With the emphasis on FGF21, we extensively reviewed the research findings on the production and regulation of FGF21 and its role in muscle metabolism. We also emphasize how the FGF21 metabolic networks mediate mitochondrial dysfunction, glycogen consumption, and myogenic development and investigate prospective directions for the functional exploitation of FGF21 and its downstream effectors, such as the mammalian target of rapamycin (mTOR).

Comparison of the effects of pea protein and whey protein on the metabolic profile of soccer athletes: a randomized, double-blind, crossover trial

Introduction

Pea protein (PP) concentrate is a plant-based alternative to animal protein sources, such as whey protein (WP). In addition to its valuable amino acid composition, PP has a low environmental impact, making it a sustainable, nutritious, and viable alternative for enhanced sports performance, such as in soccer. PP Therefore, this study aimed to evaluate the effects of PP and WP supplementation on biochemical and metabolic parameters in soccer players.

Methods

Twelve male under-20 soccer players were included in this double-blind, randomized crossover intervention study. For 10 consecutive days, each participant received either 0.5 g/kg of the PP or WP supplementation after training, starting 7 days before the test game, and continuing until 2 days after. After a 4-day washout period, the athletes switched groups and the intervention was restarted. Blood samples were collected before and after the game, as well as 24 h, 48 h, and 72 h intervals thereafter. Creatine kinase (CK), aspartate transaminase, alanine transaminase (ALT), lactate (LA), urea, creatinine, and uric acid were analyzed using commercial kits. Exploratory metabolic profiling of the serum samples was performed using nuclear magnetic resonance spectroscopy.

Results

A comparison of biochemical markers showed that the PP group had lower CK in the post-game moment, 24 h, and 48 h. Lower LA in the post-game moment, and lower ALT in the post-game moment and at 24 h. Of the 48 metabolites analyzed, 22 showed significant differences between the time points, such as amino acids, ketone bodies, and glucose metabolism. Glutamate and lactate levels significantly increased between the pre- and post-game moments in the WP group. After the game, the WP group exhibited reduced levels of metabolites such as arginine and taurine, whereas no such change was observed in the PP group. There was no difference in metabolites 72 h after the game.

Conclusions

Despite the slight advantage of the PP group in specific biochemical markers, these differences are not sufficient to justify the choice of a particular type of protein. However, the results highlight the viability of plant protein as a potential alternative to animal protein without compromising athletic performance or recovery.

Evaluation of pea/rice and amylopectin/chromium as an alternative protein source to improve muscle protein synthesis in rats

BACKGROUND

A preclinical study reported that the combination of an amylopectin/chromium complex (ACr) of branched-chain amino acids (BCAA) significantly enhanced muscle protein synthesis (MPS). This study was conducted to determine the effects of the addition of ACr complex to a pea/rice (PR) protein on MPS, insulin, muslin levels, and the mTOR pathway in exercised rats.

METHODS

Twenty-four rats were divided into three groups: (i) exercise (Ex); (ii) Ex + PR 1:1 blend (0.465 g/kg BW); (iii) Ex + PR + ACr (0.155 g/kg BW). On the day of single-dose administration, after the animals were exercised at 26/m/min for 2 h, the supplement was given by oral gavage. The rats were injected with a bolus dose (250 mg/kg BW, 25 g/L) of deuterium-labeled phenylalanine to determine the protein fractional synthesis rate (FSR) one h after consuming the study product.

RESULTS

The combination of PR and ACr enhanced MPS by 42.55% compared to the Ex group, while Ex + PR alone increased MPS by 30.2% over the Ex group (p < 0.0001) in exercised rats. Ex + PR plus ACr significantly enhanced phosphorylation of mTOR and S6K1 (p < 0.0001), and 4E-BP1 (p < 0.001) compared to the Ex (p < 0.0001). PR to ACr also significantly increased insulin and musclin levels (p < 0.0001) in exercised rats. Additionally, compared to Ex + PR alone, Ex + PR + ACr enhanced mTOR (p < 0.0001) and S6K1 (p < 0.0001) levels.

CONCLUSION

These data suggested that PR + ACr may provide an alternative to animal proteins for remodeling and repairing muscle by stimulating MPS and mTOR signaling pathways in post-exercised rats. More preclinical and clinical human studies on combining pea/rice and amylopectin/chromium complex are required.

Effect of Aerobic Exercise on Intestinal Microbiota with Amino Acids and Short-Chain Fatty Acids in Methamphetamine-Induced Mice

This study aimed to investigate the changes in intestinal homeostasis and metabolism in mice after methamphetamine (MA) administration and exercise intervention. In this study, male C57BL/B6J mice were selected to establish a model of methamphetamine-induced addiction, and the gut microbiota composition, short-chain fatty acids (SCFAs), and amino acid levels were assessed by 16S rRNA, liquid chromatography–tandem mass spectrometry, and gas chromatography–tandem mass spectrometry, respectively. The results showed that 23 dominant microbiota, 12 amino acids, and 1 SCFA were remarkably higher and 9 amino acids and 6 SCFAs were remarkably lower in the exercise model group than in the control group. Among the top 10 markers with opposite trends between the exercise intervention group and model group, the differential microbiomes included Oscillibacter, Alloprevotella, Colidextribacter, Faecalibaculum, Uncultured, Muribaculaceae, and Negativibacillus; amino acids included proline; and SCFAs included isovaleric acid and pentanoic acid. Proline was negatively correlated with Negativibacillus and positively correlated with pentanoic acid. The results suggested that moderate-intensity aerobic exercise may modulate changes in the composition of the gut microbiota and the levels of amino acids and SCFAs induced by MA administration.

Aorta- and liver-generated TMAO enhances trained immunity for increased inflammation via ER stress/mitochondrial ROS/glycolysis pathways

We determined whether gut microbiota-produced trimethylamine (TMA) is oxidized into trimethylamine N-oxide (TMAO) in nonliver tissues and whether TMAO promotes inflammation via trained immunity (TI). We found that endoplasmic reticulum (ER) stress genes were coupregulated with MitoCarta genes in chronic kidney diseases (CKD); TMAO upregulated 190 genes in human aortic endothelial cells (HAECs); TMAO synthesis enzyme flavin-containing monooxygenase 3 (FMO3) was expressed in human and mouse aortas; TMAO transdifferentiated HAECs into innate immune cells; TMAO phosphorylated 12 kinases in cytosol via its receptor PERK and CREB, and integrated with PERK pathways; and PERK inhibitors suppressed TMAO-induced ICAM-1. TMAO upregulated 3 mitochondrial genes, downregulated inflammation inhibitor DARS2, and induced mitoROS, and mitoTEMPO inhibited TMAO-induced ICAM-1. β-Glucan priming, followed by TMAO restimulation, upregulated TNF-α by inducing metabolic reprogramming, and glycolysis inhibitor suppressed TMAO-induced ICAM-1. Our results have provided potentially novel insights regarding TMAO roles in inducing EC activation and innate immune transdifferentiation and inducing metabolic reprogramming and TI for enhanced vascular inflammation, and they have provided new therapeutic targets for treating cardiovascular diseases (CVD), CKD-promoted CVD, inflammation, transplantation, aging, and cancer.

Synergistic Effect of Increased Total Protein Intake and Strength Training on Muscle Strength: A Dose-Response Meta-analysis of Randomized Controlled Trials

Background

Protein supplementation augments muscle strength gain during resistance training. Although some studies focus on the dose-response relationship of total protein intake to muscle mass or strength, the detailed dose-response relationship between total protein intake and muscle strength increase is yet to be clarified, especially in the absence of resistance training.

Objective

We aimed to assess the detailed dose-response relationship between protein supplementation and muscle strength, with and without resistance training.

Design

Systematic review with meta-analysis.

Data Sources

PubMed and Ichushi-Web (last accessed on March 23, 2022).

Eligibility Criteria

Randomized controlled trials investigating the effects of protein intake on muscle strength.

Synthesis Methods

A random-effects model and a spline model.

Results

A total of 82 articles were obtained for meta-analyses, and data from 69 articles were used to create spline curves. Muscle strength increase was significantly augmented only with resistance training (MD 2.01%, 95% CI 1.09–2.93) and was not augmented if resistance training was absent (MD 0.13%, 95% CI − 1.53 to 1.79). In the dose-response analysis using a spline model, muscle strength increase with resistance training showed a dose-dependent positive association with total protein intake, which is 0.72% (95% CI 0.40–1.04%) increase in muscle strength per 0.1 g/kg body weight [BW]/d increase in total protein intake up to 1.5 g/kg BW/d, but no further gains were observed thereafter.

Conclusion

Concurrent use of resistance training is essential for protein supplementation to improve muscle strength. This study indicates that 1.5 g/kg BW/d may be the most appropriate amount of total protein intake for maintaining and augmenting muscle strength along with resistance training.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00508-w.

Effect of the BCAT2 polymorphism (rs11548193) on plasma branched-chain amino acid concentrations after dietary intervention in subjects with obesity and insulin resistance

Branched-chain amino acids (BCAA) are considered markers of insulin resistance (IR) in subjects with obesity. In this study, we evaluated whether the presence of the SNP of the branched-chain aminotransferase 2 (BCAT2) gene can modify the effect of a dietary intervention (DI) on the plasma concentration of BCAA in subjects with obesity and IR. A prospective cohort study of adult subjects with obesity, BMI ≥ 30 kg/m², homeostatic model assessment-insulin resistance (HOMA-IR ≥ 2·5) no diagnosed chronic disease, underwent a DI with an energy restriction of 3140 kJ/d and nutritional education for 1 month. Anthropometric measurements, body composition, blood pressure, resting energy expenditure, oral glucose tolerance test results, serum biochemical parameters and the plasma amino acid profile were evaluated before and after the DI. SNP were assessed by the TaqMan SNP genotyping assay. A total of eighty-two subjects were included, and fifteen subjects with a BCAT2 SNP had a greater reduction in leucine, isoleucine, valine and the sum of BCAA. Those subjects also had a greater reduction in skeletal muscle mass, fat-free mass, total body water, blood pressure, muscle strength and biochemical parameters after 1 month of the DI and adjusting for age and sex. This study demonstrated that the presence of the BCAT2 SNP promotes a greater reduction in plasma BCAA concentration after adjusting for age and sex, in subjects with obesity and IR after a 1-month energy-restricted DI.

Intensified training in adolescent female athletes: a crossover study of Greek yogurt effects on indices of recovery

Background

During a period of intensified exercise (e.g. training/identification camps), often undertaken by competitive youth athletes, the maintenance of muscle function and peak performance can become challenging due to an accumulation of fatigue. The provision of post-exercise dairy protein in adults has been previously shown to accelerate recovery; however, its efficacy in youth athletes is currently unknown. Therefore, the purpose of this study was to examine the effects of increased dairy protein consumption with plain Greek yogurt (GY) on performance and recovery indices during an intensified soccer training camp in adolescent female soccer players.

Methods

Thirteen players (14.3 ± 1.3 years) participated in a randomized, double blinded, crossover design study where they received 3 servings/day of either GY (~115 kcal, 17 g protein, ~11.5 g carbohydrates) or an isoenergetic carbohydrate control (CHO, ~115 kcal, 0.04 g protein, ~28.6 g carbohydrates) during two 5-day soccer-specific training camps. Performance was assessed before and after each training camp. Fasted, morning, creatine kinase (CK), insulin-like growth factor-1 (IGF-1), C-reactive protein (CRP), interleukin 6 (IL6), interleukin 10 (IL10) and tumor necrosis factor-α (TNFα) were measured in plasma pre- and post-training.

Results

Training led to decrements in counter-movement jump (p = 0.01), broad jump (p = 0.04) and aerobic capacity (p = 0.006), with no effect of GY. A significant increase in anti-inflammatory cytokine IL10 was observed from pre- to post-training in GY (+26% [p = 0.008]) but not in CHO (p = 0.89). CRP and CK increased (+65% [p = 0.005] and +119% [p ≤ 0.001], respectively), while IGF-1 decreased (−34% [p ≤ 0.001]) from pre- to post-training with no difference between conditions.

Conclusions

These results demonstrate that consumption of GY did not offer any added recovery benefit with respect to measures of performance and in the attenuation of exercise-induced muscle damage above that achieved with energy-matched carbohydrate in this group of young female soccer players. However, regular consumption of GY may assist with the acute anti-inflammatory response during periods of intensified training in adolescent athletes.

Puerarin attenuates LPS-induced inflammatory injury in gastric epithelial cells by repressing NLRP3 inflammasome-mediated apoptosis

The NLRP3 inflammasome plays a crucial role in microbially induced gastric epithelial injury, but the underlying mechanisms remain unclear. Here, we aimed to assess the impacts of puerarin on LPS-induced inflammatory damage and the involvement of the AMPK/SIRT1/NLRP3 signaling pathways in this process in GES-1 cells. Cell viability and cytotoxicity were determined using CCK-8 and lactate dehydrogenase assay kits. Apoptosis was measured using annexin staining followed by flow cytometry. Cytokine levels were detected by ELISA, and protein expression was analyzed using western blotting. Protein overexpression was achieved by transfection with relevant pcDNA3.1 vectors, and protein knockdown was achieved by transfection with relevant siRNAs. Puerarin ameliorated LPS-induced cytotoxicity and apoptosis, while repressing LPS-stimulated NLRP3 inflammasome-mediated pyroptosis in GES-1 cells, as evidenced by significantly decreased expression of NLRP3, ASC, cleaved caspase-1, IL-1β and IL-18. NLRP3 knockdown efficiently repressed LPS-induced inflammatory injury in GES-1 cells. Puerarin activated the AMPK/SIRT1 pathway in LPS-treated GES-1 cells, and knockdown of both AMPK and SIRT1 reversed the protective effects of puerarin against LPS-induced inflammatory damage. AMPK overexpression strengthened, while AMPK knockdown weakened, the ability of puerarin to inhibit NLRP3-mediated inflammatory injury in LPS-treated GES-1 cells. Our findings suggest that puerarin may ameliorate LPS-induced inflammatory injury in GES-1 cells by activating the AMPK/SIRT1 signaling pathway and thereby repressing NLRP3 inflammasome-mediated apoptosis.

Mild hyperbaric oxygen for the early improvement of mood disturbance induced by high-intensity exercise

BACKGROUND

Excessive training stress can result in decreased performance and deep fatigue due to hormonal changes. There are few available data on recovery methods for mood disturbance, especially fatigue, after high-intensity training. This study, therefore, aimed to examine the effects of mild hyperbaric oxygen at 1.3 atmospheres absolute with 31% oxygen on mood disturbance induced by high-intensity exercises.

METHODS

Ten healthy adult men participated in and completed 2 trials: the control (CON) trial and the mild hyperbaric oxygen (MHO) trial. In a randomized crossover design, each subject cycled for 60 min at the physical work capacity at 75% of their maximal heart rate and were subsequently exposed to the CON and MHO conditions for 60 min as the recovery period.

RESULTS

During the 20 to 40 min recovery time points, the average change ratio of heart rates was lower in the MHO trial than in CON (p < 0.05). We observed that the fatigue-inertia, tension-anxiety, and total mood disturbance Profile of Mood States (POMS) scores decreased 60 min post-exercise in the MHO trial, but no differences of these score were observed in the CON trial. There were no differences in oxidative stress, derived-reactive oxygen metabolites, and biological antioxidant potential between both trials. These results suggest that impaired mood states induced by high-intensity exercise can be improved early by MHO without any changes in oxidative stress. This improvement may be associated with decreased heart rate secondary to MHO exposure after the high intensity exercise.

CONCLUSIONS

We conclude that MHO can improve mood disturbances, especially in the fatigue-inertia and tension-anxiety domains, after high-intensity exercise. This study suggest that MHO is potentially an effective recovery method for mood states after high-intensity training.

Intake of branched chain amino acids favors post-exercise muscle recovery and may improve muscle function: optimal dosage regimens and consumption conditions

INTRODUCTION

Numerous sportspeople consume nutritional ergogenic aids, including branched chain amino acids (BCAA), considered to favor post-exercise muscle recovery. The purpose of this study was to assess the effect of BCAA on recovery from muscle damage produced by high-intensity exercise and muscle function. This allowed to define the optimal dosage regimen and consumption conditions taking into account the combination of BCAA with other products.

EVIDENCE ACQUISITION

A systematic review of the scientific literature published over the past 15 years using the PubMed/MEDLINE, Scopus and Web of Science databases was carried out. Nineteen articles were selected.

EVIDENCE SYNTHESIS

The most optimal regimen for post-exercise muscle recovery and/or muscle function after high-intensity resistance exercise was 2-10 g BCAA/day (leucine: isoleucine: valine at 2:1:1), consumed as a supplement alone or combined with arginine and carbohydrates, 3 previous days before exercise, immediately before and after exercise, regardless of training level. This treatment can improve perceived muscle damage, fatigue, circumference of arm/leg, counter movement jump, maximum muscle strength and maximum voluntary contraction, and reduce creatine kinase and lactate dehydrogenase levels, mainly in young males.

CONCLUSIONS

Intake of BCAA favors post-exercise muscle recovery and may improve muscle function. The present review can serve as a guidance for high intensity endurance athletes who need to reduce post-exercise muscle damage and maintain or improve muscle function, especially in training periods and competition events planned with short rest periods.

Effects of melatonin on insulin signaling and inflammatory pathways of rats with apical periodontitis

AIM

To verify the effects of melatonin supplementation on insulin sensitivity, plasma concentrations of inflammatory cytokines, insulin signalling and inflammatory pathways in the soleus (SM) and extensor digitorum longus (EDL) muscles of rats with apical periodontitis (AP).

METHODOLOGY

Seventy-two Wistar rats were distributed into 4 groups: (a) control (C), (b) control supplemented with melatonin (M), (c) AP (AP), and (d) AP supplemented with melatonin (AP + M). AP was induced by pulp exposure of the maxillary and mandibular right first and second molars to the oral environment. After AP induction, oral supplementation with 5 mg kg^-1 melatonin (diluted in drinking water) for 60 days was initiated. At the end of the treatment, the following were analysed: (1) plasma concentrations of insulin and inflammatory cytokines (TNF-α, IL-6, IL-1β and IL-10) using ELISA kits; (2) glycaemia using enzymatic assay; (3) insulin resistance using homoeostasis model assessment of insulin resistance (HOMA-IR) index; and (4) phosphorylation status of pp185 tyrosine, Akt serine, IKKα/β, and JNK in SM and EDL using Western blot. Analysis of variance of two or three factors was performed, followed by the Bonferroni test. P values < 0.05 were considered statistically significant.

RESULTS

AP promoted insulin resistance, significantly increased (P < 0.05) plasma concentrations of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), significantly decreased (P < 0.05) the concentration of anti-inflammatory cytokine IL-10, impaired insulin signalling in SM, and increased IKKα/β phosphorylation status in SM and EDL. Melatonin supplementation in rats with AP improved insulin sensitivity, significantly decreased (P < 0.05) TNF-α and IL-1β, significantly increased (P < 0.05) IL-10 plasma concentrations, and changed the insulin signalling in soleus muscle and IKKα/β phosphorylation status in SM and EDL muscles.

CONCLUSIONS

Melatonin is a potent adjuvant treatment for improving apical periodontitis-associated changes in insulin sensitivity, insulin signalling and inflammatory pathways. In addition, the negative impact of AP on general health was also demonstrated.

Self-Eating for Muscle Fitness: Autophagy in the Control of Energy Metabolism

Cellular processes that sense and transmit metabolic changes are crucial for adaptation to external signals. In this regard, autophagy provides energy upon nutrient deprivation and represents a quality control mechanism that eliminates damaged organelles or proteins. Here, we review recent findings on the metabolic pathways controlling autophagy in skeletal muscle, a plastic tissue that undergoes major changes in energy demands. We also analyze the implications of autophagy in the regulation of energy metabolism in muscle and how alterations in this process affect energy homeostasis at the whole-body level and the development of metabolic diseases and aging.

Effects of Post-Exercise Whey Protein Consumption on Recovery Indices in Adolescent Swimmers

Purpose: This study examined the effect of whey protein consumption following high-intensity interval swimming (HIIS) on muscle damage, inflammatory cytokines and performance in adolescent swimmers. Methods: Fifty-four swimmers (11-17 years-old) were stratified by age, sex and body mass to a whey protein (PRO), isoenergetic carbohydrate (CHO) or a water/placebo (H₂O) group. Following baseline blood samples (06:00 h) and a standardised breakfast, participants performed a maximal 200 m swim, followed by HIIS. A total of two post-exercise boluses were consumed following HIIS and ~5 h post-baseline. Blood and 200 m performance measurements were repeated at 5 h, 8 h and 24 h from baseline. Muscle soreness was assessed at 24 h. Creatine kinase (CK), interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α) were measured in plasma. Results: No difference in 200 m swim performance was observed between groups. CK activity was elevated at 5 h compared to baseline and 24 h and at 8 h compared to all other timepoints, with no differences between groups. Muscle soreness was lower in PRO compared to H₂O (p = 0.04). Anti-inflammatory IL-10 increased at 8 h in PRO, while it decreased in CHO and H₂O. Conclusions: Post-exercise consumption of whey protein appears to have no additional benefit on recovery indices following HIIS compared to isoenergetic amounts of carbohydrate in adolescent swimmers. However, it may assist with the acute-inflammatory response.

Hydrolyzed peptides from purple perilla (Perilla frutescens L. Britt.) seeds improve muscle synthesis and exercise performance in mice

The purple perilla (Perilla frutescens L. Britt.) seed peptides (PPSP) were obtained and their improvement of muscle synthesis and exercise performance was investigated in this work. Results showed that the weight-average molecular weight of the PPSP was 869 Dalton. The PPSP were rich in branched-chain amino acids (18.82 g/100 g) and anti-fatigue amino acids, including glutamate (Glu), aspartic acid (Asp), and arginine (Arg). After the administration of PPSP at 1.2 g kg^-1  day^-1 for 4 weeks, the muscle coefficient and muscle fiber thickness in mice displayed a distinct (p < .05) increase via the upregulation of myogenic differentiation (MyoD) and myogenin (MyoG). The improved muscle strength and exercise tolerance were also observed. Simultaneously, the levels of the biochemical blood markers associated with fatigue and the glycogen degradation in liver and muscle were significantly (p < .05) suppressed. These results suggested that PPSP could effectively promote muscle synthesis and ameliorate exercise fatigue. PRACTICAL APPLICATIONS: Purple perilla is an annual herbal plant and widely grown in Asian countries as an important crop and food. It is believed that the protein content of purple perilla seeds can reach 23.7%, and the protein is rich in essential amino acids. However, the information about the beneficial effects of their proteins or peptides on muscle synthesis and anti-exercise fatigue were still limited. The present results discovered that the PPSP can effectively promote the growth of muscle tissue and improve exercise tolerance. It is indicated that PPSP may have a potential application value in partly or completely replacing animal proteins such as whey protein.