Plasma BCAA concentrations during exercise of varied intensities in young healthy men-the impact of endurance training

The Hormetic Adaptative Capacity and Resilience to Oxidative Stress Is Strengthened by Exposome Enrichment with Air Cold Atmospheric Plasma: A Metabolome Targeted Follow-Up Approach

Background/Objectives: The exposome, encompassing all environmental influences on health, plays a pivotal role in oxidative stress-related diseases. Negative air ions (NAIs), generated via cold atmospheric plasma (CAP), have been proposed as potential modulators of oxidative resilience. This study aims to investigate the metabolic adaptations induced by prolonged exposure to an NAI-enriched environment in mice, focusing on its effects in oxidative stress markers and energy metabolism in liver and blood. Methods: Twenty male C57BL/6J mice were divided into four groups: two experimental groups exposed to NAI-enriched air generated by an Air Cold Atmospheric Plasma-Nanoparticle Removal (aCAP-NR) device for either 18 days (short-term, ST) or 28 days (long-term, LT), and two control groups without exposure. Targeted metabolomics was performed in whole blood and liver using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). Statistical and pathway analyses were conducted to assess metabolic alterations. Results: Metabolic profiling revealed significant shifts in oxidative stress-related pathways, including enhanced glutathione metabolism, reduced lipid peroxidation, and modulation of purine metabolism. Short-term exposure led to increased mitochondrial efficiency and energy homeostasis, while long-term exposure induced adaptive metabolic reprogramming, with higher inosine levels suggesting enhanced antioxidant and anti-inflammatory responses. No adverse effects on systemic or hepatic health markers were observed. Conclusions: NAI exposure via aCAP-NR elicits a hormetic response, enhancing metabolic efficiency and resilience to oxidative stress. These findings suggest that controlled environmental enrichment with NAIs may serve as a novel non-invasive strategy for mitigating oxidative damage and improving metabolic health, as hormetic adaptative capacity and resilience to oxidative stress, warranting further translational research.

Physical activity of moderate-intensity optimizes myocardial citrate cycle in a murine model of heart failure

Introduction

There is growing body of evidence that an enhanced concentration of branched-chain amino acids (BCAAs), as a consequence of an impaired myocardial oxidative metabolism, is involved in the occurrence and progression of heart failure (HF). The purpose of this study was to examine the effect of 8 weeks of spontaneous wheel running (8-sWR) (reflecting low-to-moderate intensity physical activity) on the myocardial [BCAAs] and mitochondrial oxidative metabolism markers, such as tricarboxylic acid (TCA) cycle intermediates (TCAi), mitochondrial electron transport chain (ETC) proteins and mitochondrial DNA copy number (mtDNA/nDNA) in a murine model of HF.

Methods

Adult heart failure (Tgαq*44) and wild-type (WT) mice were randomly assigned to either the sedentary or exercising group. Myocardial concentrations of [TCAi] and [BCAAs] were measured by LC-MS/MS, ETC proteins were determined by Western immunoblotting and mtDNA/nDNA was assessed by qPCR.

Results

Heart failure mice exhibited decreased exercise performance capacity as reflected by a lower total distance covered and time of running in wheels. This was accompanied by impaired TCA cycle, including higher citrate concentration and greater [BCAAs] in the heart of Tgαq*44 mice compared to their control counterparts. No impact of disease at its current stage i.e., in the transition phase from the compensated to decompensated stage of HF on the myocardial mitochondrial ETC, proteins content was observed, however the altered basal level of mitochondrial biogenesis (lower mtDNA/nDNA) in the heart of Tgαq*44 mice compared to their control counterparts was detected. Interestingly, 8-sWR significantly decreased myocardial citrate content in the presence of unchanged myocardial [BCAAs], ETC proteins content and mtDNA copy number.

Conclusion

Moderate-intensity physical activity, even of short duration, could be considered an effective intervention in heart failure. Our results suggest that central metabolic pathway - TCA cycle appears to be more sensitive to moderate-intensity physical activity (as reflected by the lowering of myocardial citrate concentration) than the mechanism(s) regulating the BCAAs turnover in the heart. This observation may have a particular importance in heart failure, since an improvement of impaired myocardial oxidative metabolism may contribute to the upgrading of the clinical status of patients.

Aerobic exercise attenuates insulin resistance via restoring branched chain amino acids homeostasis in obese mice

Introduction

Emerging evidences suggests that the disrupted branched-chain amino acids (BCAAs) homeostasis and elevated BCAAs promote obesity-related insulin resistance (IR). Exercise improves insulin sensitivity. However, whether BCAAs plays a role in the exercise-attenuated IR remains to be fully investigated.

Methods

In this study, male C57BL/6J mice were induced to become diet-induced obese (DIO) and served as subjects. The initial investigation focused on the impact of exercise on IR and BCAAs. The DIO mice were randomly assigned to either a sedentary group (CON, n = 16) or an exercise group (EX, n = 16). The EX group underwent a 12-week aerobic exercise regimen on a treadmill. After 12-week, plasma BCAAs and branched-chain keto acids (BCKAs) were measured by liquid chromatography-mass spectrometry, glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed, and the expression and phosphorylation of BCAAs catabolic proteins, as well as AKT T308 in gastrocnemius muscle and liver tissues, were evaluated using western blotting. Subsequently, the study explored the role of BCAAs in enhancing IR through exercise. Mice were randomly allocated into 4 groups: sedentary group (CON, n = 8), sedentary with BCAAs supplementation group (CON+BCAA, n = 8), exercise group (EX, n = 16), and exercise with BCAAs supplementation group (EX+BCAA, n = 16). The exercise protocol was as above. Mice in the BCAAs supplemented groups received drinking water containing 2% BCAAs. After 12-week, plasma BCAAs and BCKAs were measured, GTT and ITT tests were performed, and the phosphorylation of AKT T308, as well as p70S6K T389 in gastrocnemius muscle and liver, were compared between the EX group and the EX+BCAA group. Additionally, the phosphorylation of AMPKα T172 in both tissues was measured across all four groups.

Results

12-week aerobic exercise improved insulin sensitivity in DIO mice while inducing BCAAs catabolic protein expression in skeletal muscle and liver, and reducing the plasma BCAAs level. Importantly, BCAAs supplementation elevated the plasma level of BCAAs and counteracted the exercise-attenuated IR. In skeletal muscle and liver tissues, BCAAs supplementation impaired the exercise-improved insulin signaling without enhancing mammalian target of rapamycin activity. AMPK activity was enhanced by aerobic exercise, which was abolished by BCAAs supplementation.

Conclusion

Aerobic exercise attenuated insulin resistance via restoring BCAAs homeostasis and AMPK activity. The impacts of BCAAs intake on the metabolic effects of exercise sheds light on the combined exercise and nutrition intervention strategy for diabetes management.

Elevated BCAA catabolism reverses the effect of branched-chain ketoacids on glucose transport in mTORC1-dependent manner in L6 myotubes

Plasma levels of branched-chain amino acids (BCAA) and their metabolites, branched-chain ketoacids (BCKA), are increased in insulin resistance. We previously showed that ketoisocaproic acid (KIC) suppressed insulin-stimulated glucose transport in L6 myotubes, especially in myotubes depleted of branched-chain ketoacid dehydrogenase (BCKD), the enzyme that decarboxylates BCKA. This suggests that upregulating BCKD activity might improve insulin sensitivity. We hypothesised that increasing BCAA catabolism would upregulate insulin-stimulated glucose transport and attenuate insulin resistance induced by BCKA. L6 myotubes were either depleted of BCKD kinase (BDK), the enzyme that inhibits BCKD activity, or treated with BT2, a BDK inhibitor. Myotubes were then treated with KIC (200 μM), leucine (150 μM), BCKA (200 μM), or BCAA (400 μM) and then treated with or without insulin (100 nM). BDK depletion/inhibition rescued the suppression of insulin-stimulated glucose transport by KIC/BCKA. This was consistent with the attenuation of IRS-1 (Ser612) and S6K1 (Thr389) phosphorylation but there was no effect on Akt (Ser473) phosphorylation. The effect of leucine or BCAA on these measures was not as pronounced and BT2 did not influence the effect. Induction of the mTORC1/IRS-1 (Ser612) axis abolished the attenuating effect of BT2 treatment on glucose transport in cells treated with KIC. Surprisingly, rapamycin co-treatment with BT2 and KIC further reduced glucose transport. Our data suggests that the suppression of insulin-stimulated glucose transport by KIC/BCKA in muscle is mediated by mTORC1/S6K1 signalling. This was attenuated by upregulating BCAA catabolic flux. Thus, interventions targeting BCAA metabolism may provide benefits against insulin resistance and its sequelae.

Exercise-induced response of proteinogenic and non-proteinogenic plasma free amino acids is sport-specific: A comparison of sprint and endurance athletes

Circulating blood is an important plasma free amino acids (PFAAs) reservoir and a pivotal link between metabolic pathways. No comparisons are available between athletes with opposite training adaptations that include a broader spectrum of both proteinogenic and non-proteinogenic amino acids, and that take into account skeletal muscle mass. We hypothesized that the levels of the exercise-induced PFAAs concentration are related to the type of training-related metabolic adaptation. We compared highly trained endurance athletes (n = 11) and sprinters (n = 10) aged 20‒35 years who performed incremental exercise until exhaustion. Venous blood was collected before and during the test and 30-min recovery (12 samples). Forty-two PFAAs were assayed using LC-ESI-MS/MS technique. Skeletal muscle mass was estimated using dual X-ray absorptiometry method. Glutamine and alanine were dominant PFAAs throughout the whole exercise and recovery period (~350‒650 μmol∙L-1). Total, combined proteinogenic, non-essential, and non-proteinogenic PFAAs levels were significantly higher in endurance athletes than sprinters (ANOVA group effects: p = 0.007, η2 = 0.321; p = 0.011, η2 = 0.294; p = 0.003, η2 = 0.376; p = 0.001, η2 = 0.471, respectively). The exercise response was more pronounced in endurance athletes, especially for non-proteinogenic PFAAs (ANOVA interaction effect: p = 0.038, η2 = 0.123). Significant between-group differences were observed for 19 of 33 PFAAs detected, including 4 essential, 7 non-essential, and 8 non-proteinogenic ones. We demonstrated that the PFAAs response to incremental aerobic exercise is associated with the type of training-related metabolic adaptation. A greater turnover and availability of circulating PFAAs for skeletal muscles and other body tissues is observed in endurance- than in sprint-trained individuals. Non-proteinogenic PFAAs, despite low concentrations, also respond to exercise loads, indicating their important, though less understood role in exercise metabolism. Our study provides additional insight into the exercise-induced physiological response of PFAAs, and may also provide a rationale in discussions regarding dietary amino acid requirements in high-performance athletes with respect to sports specialization.

Changes in Plasma Free Amino Acid Profile in Endurance Athletes over a 9-Month Training Cycle

We aimed to evaluate long-term changes in proteinogenic and non-proteinogenic plasma free amino acids (PFAA). Eleven male endurance triathletes participated in a 9-month study. Blood was collected at rest, immediately after exhaustive exercise, and during 30-min recovery, in four consecutive training phases: transition, general, specific, and competition. Twenty proteinogenic and 22 non-proteinogenic PFAAs were assayed using the LC-ESI-MS/MS technique. The structured training modified the patterns of exercise-induced PFAA response, with the competition phase being the most distinct from the others. Branched-chain amino acids (p = 0.002; η2 = 0.216), phenylalanine (p = 0.015; η2 = 0.153), methionine (p = 0.002; η2 = 0.206), and lysine (p = 0.006; η2 = 0.196) declined more rapidly between rest and exhaustion in the competition phase. Glutamine (p = 0.008; η2 = 0.255), glutamate (p = 0.006; η2 = 0.265), tyrosine (p = 0.001; η2 = 0.195), cystine (p = 0.042; η2 = 0.183), and serine (p < 0.001; η2 = 0.346) levels were reduced in the competition phase. Arginine (p = 0.046; η2 = 0.138) and aspartate (p = 0.011; η2 = 0.171) levels were highest during exercise in the transition phase. During the competition phase, α-aminoadipic acid (p = 0.023; η2 = 0.145), β-aminoisobutyric acid (p = 0.007; η2 = 0.167), β-alanine (p < 0.001; η2 = 0.473), and sarcosine (p = 0.017; η2 = 0.150) levels increased, whereas phosphoethanolamine (p = 0.037; η2 = 0.189) and taurine (p = 0.008; η2 = 0.251) concentrations decreased. Overtraining indicators were not elevated. The altered PFAA profile suggests adaptations within energy metabolic pathways such as the tricarboxylic acid cycle, oxidative phosphorylation, ammonia neutralization, the purine nucleotide cycle, and buffering of intracellular H+ ions. The changes seem to reflect normal adaptations.

Coordinated Metabolic Responses Facilitate Cardiac Growth in Pregnancy and Exercise

PURPOSE OF REVIEW

Pregnancy and exercise are systemic stressors that promote physiological growth of the heart in response to repetitive volume overload and maintenance of cardiac output. This type of remodeling is distinct from pathological hypertrophy and involves different metabolic mechanisms that facilitate growth; however, it remains unclear how metabolic changes in the heart facilitate growth and if these processes are similar in both pregnancy- and exercise-induced cardiac growth.

RECENT FINDINGS

The ability of the heart to metabolize a myriad of substrates balances cardiac demands for energy provision and anabolism. During pregnancy, coordination of hormonal status with cardiac reductions in glucose oxidation appears important for physiological growth. During exercise, a reduction in cardiac glucose oxidation also appears important for physiological growth, which could facilitate shuttling of glucose-derived carbons into biosynthetic pathways for growth. Understanding the metabolic underpinnings of physiological cardiac growth could provide insight to optimize cardiovascular health and prevent deleterious remodeling, such as that which occurs from postpartum cardiomyopathy and heart failure. This short review highlights the metabolic mechanisms known to facilitate pregnancy-induced and exercise-induced cardiac growth, both of which require changes in cardiac glucose metabolism for the promotion of growth. In addition, we mention important similarities and differences of physiological cardiac growth in these models as well as discuss current limitations in our understanding of metabolic changes that facilitate growth.

Exercise-regulated white adipocyte differentitation: An insight into its role and mechanism

White adipocytes play a key role in the regulation of fat mass amount and energy balance. An appropriate level of white adipocyte differentiation is important for maintaining metabolic homeostasis. Exercise, an important way to improve metabolic health, can regulate white adipocyte differentiation. In this review, the effect of exercise on the differentiation of white adipocytes is summarized. Exercise could regulate adipocyte differentiation in multiple ways, such as exerkines, metabolites, microRNAs, and so on. The potential mechanism underlying the role of exercise in adipocyte differentiation is also reviewed and discussed. In-depth investigation of the role and mechanism of exercise in white adipocyte differentiation would provide new insights into exercise-mediated improvement of metabolism and facilitate the application of exercise-based strategy against obesity.

Exploring the association of physical activity with the plasma and urine metabolome in adolescents and young adults

BACKGROUND

Regular physical activity elicits many health benefits. However, the underlying molecular mechanisms through which physical activity influences overall health are less understood. Untargeted metabolomics enables system-wide mapping of molecular perturbations which may lend insights into physiological responses to regular physical activity. In this study, we investigated the associations of habitual physical activity with plasma and urine metabolome in adolescents and young adults.

METHODS

This cross-sectional study included participants from the DONALD (DOrtmund Nutritional and Anthropometric Longitudinally Designed) study with plasma samples n = 365 (median age: 18.4 (18.1, 25.0) years, 58% females) and 24 h urine samples n = 215 (median age: 18.1 (17.1, 18.2) years, 51% females). Habitual physical activity was assessed using a validated Adolescent Physical Activity Recall Questionnaire. Plasma and urine metabolite concentrations were determined using ultra-high-performance liquid chromatography-tandem mass spectroscopy (UPLC-MS/MS) methods. In a sex-stratified analysis, we conducted principal component analysis (PCA) to reduce the dimensionality of metabolite data and to create metabolite patterns. Multivariable linear regression models were then applied to assess the associations between self-reported physical activity (metabolic equivalent of task (MET)-hours per week) with single metabolites and metabolite patterns, adjusted for potential confounders and controlling the false discovery rate (FDR) at 5% for each set of regressions.

RESULTS

Habitual physical activity was positively associated with the "lipid, amino acids and xenometabolite" pattern in the plasma samples of male participants only (β = 1.02; 95% CI: 1.01, 1.04, p = 0.001, adjusted p = 0.042). In both sexes, no association of physical activity with single metabolites in plasma and urine and metabolite patterns in urine was found (all adjusted p > 0.05).

CONCLUSIONS

Our explorative study suggests that habitual physical activity is associated with alterations of a group of metabolites reflected in the plasma metabolite pattern in males. These perturbations may lend insights into some of underlying mechanisms that modulate effects of physical activity.

Intertwined Relationship of Mitochondrial Metabolism, Gut Microbiome and Exercise Potential

The microbiome has emerged as a key player contributing significantly to the human physiology over the past decades. The potential microbial niche is largely unexplored in the context of exercise enhancing capacity and the related mitochondrial functions. Physical exercise can influence the gut microbiota composition and diversity, whereas a sedentary lifestyle in association with dysbiosis can lead to reduced well-being and diseases. Here, we have elucidated the importance of diverse microbiota, which is associated with an individual's fitness, and moreover, its connection with the organelle, the mitochondria, which is the hub of energy production, signaling, and cellular homeostasis. Microbial by-products, such as short-chain fatty acids, are produced during regular exercise that can enhance the mitochondrial capacity. Therefore, exercise can be employed as a therapeutic intervention to circumvent or subside various metabolic and mitochondria-related diseases. Alternatively, the microbiome-mitochondria axis can be targeted to enhance exercise performance. This review furthers our understanding about the influence of microbiome on the functional capacity of the mitochondria and exercise performance, and the interplay between them.

Branched chain amino acids-friend or foe in the control of energy substrate turnover and insulin sensitivity?

Branched chain amino acids (BCAA) and their derivatives are bioactive molecules with pleiotropic functions in the human body. Elevated fasting blood BCAA concentrations are considered as a metabolic hallmark of obesity, insulin resistance, dyslipidaemia, nonalcoholic fatty liver disease, type 2 diabetes and cardiovascular disease. However, since increased BCAA amount is observed both in metabolically healthy and obese subjects, a question whether BCAA are mechanistic drivers of insulin resistance and its morbidities or only markers of metabolic dysregulation, still remains open. The beneficial effects of BCAA on body weight and composition, aerobic capacity, insulin secretion and sensitivity demand high catabolic potential toward amino acids and/or adequate BCAA intake. On the opposite, BCAA-related inhibition of lipogenesis and lipolysis enhancement may preclude impairment in insulin sensitivity. Thereby, the following review addresses various strategies pertaining to the modulation of BCAA catabolism and the possible roles of BCAA in energy homeostasis. We also aim to elucidate mechanisms behind the heterogeneity of ramifications associated with BCAA modulation.

Classical homocystinuria, is it safe to exercise?

Background Cystationine β-synthase (CBS) deficiency is a genetic disorder characterized by severe hyperhomocysteinemia and thrombotic complications. In healthy individuals, physical exercise may result in a transient increase in plasma total homocysteine (tHcy) raising the possibility that exercise might be detrimental in CBS deficiency. Our main objective was to determine plasma tHcy kinetics in response to physical exercise in homocystinuria patients. Methods Six adult patients (2 males, 4 females) with homocystinuria and 6 age- and gender-matched controls completed a 30-min aerobic exercise of moderate-intensity with fixed power output (50 W for women and 100 W for men). Blood samples were drawn before, immediately, 180 min and 24 h after exercise. tHcy levels were determined by standard procedures; substrate oxidation and energy expenditure were measured using indirect calorimetry. Results Acute exercise was well tolerated and safe in patients and controls. During the exercise bout, heart rate and energy expenditure increased equally in both groups. tHcy levels were higher in patients compared to controls at all time points (p < 0.05). There was no significant effect of exercise on tHcy levels at any time point (p = 0.36). Although two patients with partial pyridoxine responsiveness presented higher homocysteine responses, their highest value remained below 55 μmol/l. Conclusions Overall metabolic responses to acute exercise were similar between homocystinuria patients and controls; specifically, exercise did not significantly change tHcy concentrations. Moderate physical exercise was well tolerated without any adverse event in our cohort of patients. Further studies are needed to identify the effects of different intensities and modes of exercise in larger cohorts of CBS patients with different levels of pyridoxine responsiveness.