l-Leucine Increases Skeletal Muscle IGF-1 but Does Not Differentially Increase Akt/mTORC1 Signaling and Serum IGF-1 Compared to Ursolic Acid in Response to Resistance Exercise in Resistance-Trained Men

The Effects of Protein and Supplements on Sarcopenia in Human Clinical Studies: How Older Adults Should Consume Protein and Supplements

Sarcopenia is a condition in which muscle mass, strength, and performance decrease with age. It is associated with chronic diseases such as diabetes, cardiovascular disease, and hypertension, and contributes to an increase in mortality. Because managing sarcopenia is critical for maintaining good health and quality of life for the elderly, the condition has sparked concern among many researchers. To counteract sarcopenia, intake of protein is an important factor, while a lack of either protein or vitamin D is a major cause of sarcopenia. In addition, essential amino acids, leucine, β-hydroxy β-methylbutyrate (HMB), creatine, and citrulline are used as supplements for muscle health and are suggested as alternatives for controlling sarcopenia. There are many studies on such proteins and supplements, but it is necessary to actually organize the types, amounts, and methods by which proteins and supplements should be consumed to inhibit sarcopenia. In this study, the efficacy of proteins and supplements for controlling sarcopenia according to human clinical studies is summarized to provide suggestions about how the elderly may consume proteins, amino acids, and other supplements.

The Skeletal Muscle Microbiopsy Method in Exercise and Sports Science Research: A Narrative and Methodological Review

BACKGROUND

The skeletal muscle microbiopsy protocol was introduced to the Exercise and Sports Science (ESS) research field in 1999 and has been used as a protocol to directly examine muscular structural and biochemical changes. There is much variation in the reporting of the microbiopsy protocol and its related pre-and post-procedure for participant care and sample collection. The purpose of this narrative and methodological review is to compare the microbiopsy to the traditional Bergström protocol used in the ESS field, identify and summarize all related microbiopsy protocols used in previous ESS studies and determine the most frequently used microbiopsy protocols aspects and associated pre- and post-biopsy procedures; METHODS: A review of literature up to January, 2022 was used following the PRISMA and Cochrane Methodological Review Guide to determine frequently used methods that may facilitate optimal and potential recommendations for muscle microbiopsy needle gauge (G), concentration or dose (% or mL) and administration of local anesthetic, co-axial/cannula introducer gauge (G), muscle depth (cm), muscle sample size collected (mg), passes to collect samples, time points of muscle sampling, and promotion of participant compliance and minimization of adverse events; RESULTS: 85 articles were selected based on the inclusionary requirements related to the ESS field or methodological considerations. The most frequently reported aspects in previous research to suggest the location of the vastus lateralis is the midpoint between the patella and the greater trochanter of the femur or 1/3 or 2/3 the distance from the patella to anterior superior iliac spine, 14 G biopsy needle, subcutaneous injected lidocaine administration (2 mL; 1%), 13 G co-axial/cannula, 1-2 cm muscle depth, 10-20 mg of muscle sample, ~3-time points, 2-3 passes; DISCUSSION: There is much variation in the reporting of the microbiopsy protocol and its related pre-and post-biopsy procedures. Standardization in reporting may promote recommendations to optimize data integrity, participant safety, participant adherence to the study design, and increase reproducibility. Recommendations are made for the microbiopsy procedure based on frequently reported characteristics.

14-3-3β is essential for milk composition stimulated by Leu/IGF-1 via IGF1R signaling pathway in BMECs

The cell proliferation of bovine mammary epithelial cells (BMECs) and consequent milk synthesis are regulated by multiple factors. The purpose of this study was to examine the effect of 14-3-3β on cellular proliferation and milk fat/β-casein synthesis in BMECs and reveal its underlying mechanisms. In this study, we employed gene function analysis to explore the regulatory effect and molecular mechanisms of 14-3-3β on milk synthesis and proliferation in BMECs. We found that leucine and IGF-1 enhance cell proliferation and milk synthesis in a 14-3-3β-dependent manner and only exhibiting such effect in the presence of 14-3-3β. We further determined that 14-3-3β interacts with the IGF1R self-phosphorylation site and it additionally mediated leucine and IGF-1 to stimulate the synthesis of milk through the IGF1R-AKT-mTORC1 signaling pathway. In summary, our data indicated that 14-3-3β mediates the expression of milk fat and protein stimulated by leucine and IGF-1, leading to lactogenesis through IGF1R signaling pathway in BMECs.

Ursolic acid does not change the cytokine levels following resistance training in healthy men: A pilot balanced, double-blind and placebo-controlled clinical trial

Ursolic acid (UA) is a natural compound that shows anti-inflammatory actions. However, no human studies have investigated the cytokine profile during the RT and UA consumption. The purpose of this study was to verify if UA is able to potentiate the anti-inflammatory activity after RT, reflecting in the reduction of blood inflammatory markers in healthy men. Twenty-seven participants were allocated to two groups: control (CON) (n = 13) and UA (n = 14). For 8weeks, each group performed RT and consumed capsules containing a placebo (400 mg/day) or UA (400 mg/day). Serum cytokine concentrations were evaluated before and after the training period. There was no difference in the serum cytokine concentrations of TNF-α, IL-10 and IL-6 (p > 0.05). In conclusion, UA supplementation for 8weeks was not able to change the blood TNF-α, IL-10, and IL-6 concentrations in healthy men undergoing RT. However, further studies are warranted to investigate other inflammatory markers.

Beneficial Effects of Ursolic Acid and Its Derivatives-Focus on Potential Biochemical Mechanisms in Cardiovascular Conditions

Ursolic acid (UA) is a natural pentacyclic triterpenoid found in a number of plants such as apples, thyme, oregano, hawthorn and others. Several in vitro and in vivo studies have presented its anti-inflammatory and anti-apoptotic properties. The inhibition of NF-κB-mediated inflammatory pathways and the increased scavenging of reactive oxygen species (ROS) in numerous ways seem to be the most beneficial effects of UA. In mice and rats, administration of UA appears to slow down the development of cardiovascular diseases (CVDs), especially atherosclerosis and cardiac fibrosis. Upregulation of endothelial-type nitric oxide synthase (eNOS) and cystathionine-λ-lyase (CSE) by UA may suggest its vasorelaxant property. Inhibition of metalloproteinases activity by UA may contribute to better outcomes in aneurysms management. UA influence on lipid and glucose metabolism remains inconsistent, and additional studies are essential to verify its efficacy. Furthermore, UA derivatives appear to have a beneficial impact on the cardiovascular system. This review aims to summarize recent findings on beneficial effects of UA that may make it a promising candidate for clinical trials for the management of CVDs.

Regulation of GH and GH Signaling by Nutrients

Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.

Ursolic acid has no additional effect on muscle strength and mass in active men undergoing a high-protein diet and resistance training: A double-blind and placebo-controlled trial

BACKGROUND

Ursolic acid (UA) is thought to have an anabolic effect on muscle mass in humans. This study sought to compare the effects of UA and a placebo on muscle strength and mass in young men undergoing resistance training (RT) and consuming a high-protein diet.

METHODS

A clinical, double-blind, placebo-controlled trial was conducted for 8 weeks. The Control + RT group (CON n = 12) received 400 mg/d of placebo, and the UA + RT group (UA n = 10) received 400 mg/d of UA. Both groups ingested ~1.6 g/kg of protein and performed the same RT program. Pre- and post-intervention, both groups were evaluated for anthropometric measures, body composition, food intake and muscle strength.

RESULTS

Food intake remained unchanged throughout the study. Both groups showed significant increases in body weight (CON Δ: 2.12 ± 0.47 kg, p = 0.001 vs. UA Δ: 2.24 ± 0.67 kg, p = 0.009), body mass index (BMI) (CON Δ: 0.69 ± 0.15 kg/m2, p = 0.001 vs. UA Δ: 0.75 ± 0.23, p = 0.011) and thigh circumference (CON Δ: 1.50 ± 0.36, p = 0.002 vs. UA Δ: 2.46 ± 0.50 cm, p = 0.003 vs. UA 1.84 ± 0.82 cm, p = 0.001), with differences between them. There was no difference in the arm, waist and hip circumferences. Both groups showed increases in muscle mass (CON Δ: 1.12 ± 0.26, p = 0.001 vs. UA Δ: 1.08 ± 0.28 kg, p = 0.004), but there was no significant difference between them. Additionally, there were significant increases in the one repetition maximum test in the bench press and in the 10-repetition maximum test in the knee extension (CON Δ: 5.00 ± 2.09, p = 0.036 vs. UA Δ: 7.8 ± 1.87, p = 0.340 and CON Δ: 3.58 ± 1.15, p = 0.010 vs. UA Δ: 1.20 ± 0.72, p = 0.133), respectively, with no difference between them.

CONCLUSIONS

Ursolic acid had no synergic effect on muscle strength and mass in response to RT in physically active men consuming a high-protein diet.

BRAZILIAN CLINICAL TRIALS REGISTRY (REBEC)

RBR-76tbqs.

Effects of branched-chain amino acid supplementation and resistance training in postmenopausal women

BACKGROUND

The age-related loss in muscular function is typically accelerated after menopause. Resistance training (RT) has been shown to increase muscle mass and strength in postmenopausal women. Branched-chain amino acid (BCAA) supplementation acutely increases myofibrillar protein synthesis (MPS) and decreases muscle soreness following RT. However, the combined effects of BCAA supplementation and RT on muscle mass, strength, and regulatory factors on postmenopausal cohorts are currently unknown. The purpose of this study was to explore the combined effects of BCAA supplementation and RT on muscle mass, strength, and regulatory factors in postmenopausal women.

METHODS

Thirty postmenopausal women were randomly assigned to one of three conditions: RT and placebo (PLA; n = 10), RT and BCAA (BCAA; 9 g/day; n = 10), or control (CON; n = 10). Muscle mass, strength, and serum concentrations of muscle regulatory factors (myostatin, follistatin, and insulin-like growth factor-1 [IGF-1]) were assessed before and following 8 weeks of whole-body supervised RT (3×/week, 3-4 sets using 60-75% 1-repetition maximum [1-RM]).

RESULTS

There were significant increases (P < 0.05) in muscle mass and strength in both the PLA and BCAA conditions. Additionally, myostatin significantly (P < 0.05) decreased, while IGF-1 (P < 0.05) increased following PLA and BCAA. However, follistatin significantly increased in the BCAA condition. There were no differences between RT conditions over time. Furthermore, there were no changes in any variable after CON.

CONCLUSIONS

Short-term (8 weeks) RT is an effective intervention for improving muscle mass, strength, and muscle regulatory factors in postmenopausal women. The addition of BCAA supplementation to RT failed to augment these physiological changes.

Essential Amino Acids and Protein Synthesis: Insights into Maximizing the Muscle and Whole-Body Response to Feeding

Ingesting protein-containing supplements and foods provides essential amino acids (EAA) necessary to increase muscle and whole-body protein synthesis (WBPS). Large variations exist in the EAA composition of supplements and foods, ranging from free-form amino acids to whole protein foods. We sought to investigate how changes in peripheral EAA after ingesting various protein and free amino acid formats altered muscle and whole-body protein synthesis. Data were compiled from four previous studies that used primed, constant infusions of L-(ring-2H5)-phenylalanine and L-(3,3-2H2)-tyrosine to determine fractional synthetic rate of muscle protein (FSR), WBPS, and circulating EAA concentrations. Stepwise regression indicated that max EAA concentration (EAACmax; R2 = 0.524, p < 0.001), EAACmax (R2 = 0.341, p < 0.001), and change in EAA concentration (ΔEAA; R = 0.345, p < 0.001) were the strongest predictors for postprandial FSR, Δ (change from post absorptive to postprandial) FSR, and ΔWBPS, respectively. Within our dataset, the stepwise regression equation indicated that a 100% increase in peripheral EAA concentrations increases FSR by ~34%. Further, we observed significant (p < 0.05) positive (R = 0.420-0.724) correlations between the plasma EAA area under the curve above baseline, EAACmax, ΔEAA, and rate to EAACmax to postprandial FSR, ΔFSR, and ΔWBPS. Taken together our results indicate that across a large variety of EAA/protein-containing formats and food, large increases in peripheral EAA concentrations are required to drive a robust increase in muscle and whole-body protein synthesis.

Promotion of epithelial hyperplasia by interleukin-8-CXCR axis in human prostate

BACKGROUND

The clinical manifestation of benign prostatic hyperplasia (BPH) is causally linked to the inflammatory microenvironment and proliferation of epithelial and stromal cells in the prostate transitional zone. The CXC-chemokine interleukin-8 (IL-8) contributes to inflammation. We evaluated the expression of inflammatory cytokines in clinical specimens, primary cultures, and prostatic lineage cell lines. We investigated whether IL-8 via its receptor system (IL-8 axis) promotes BPH.

METHODS

The messenger RNA and protein expression of chemokines, including components of the IL-8 axis, were measured in normal prostate (NP; n = 7) and BPH (n = 21), urine (n = 24) specimens, primary cultures, prostatic lineage epithelial cell lines (NHPrE1, BHPrE1, BPH-1), and normal prostate cells (RWPE-1). The functional role of the IL-8 axis in prostate epithelial cell growth was evaluated by CRISPR/Cas9 gene editing. The effect of a combination with two natural compounds, oleanolic acid (OA) and ursolic acid (UA), was evaluated on the expression of the IL-8 axis and epithelial cell growth.

RESULTS

Among the 19 inflammatory chemokines and chemokine receptors we analyzed, levels of IL-8 and its receptors (CXCR1, CXCR2), as well as, of CXCR7, a receptor for CXCL12, were 5- to 25-fold elevated in BPH tissues when compared to NP tissues (P ≤ .001). Urinary IL-8 levels were threefold to sixfold elevated in BPH patients, but not in asymptomatic males and females with lower urinary tract symptoms (P ≤ .004). The expression of the IL-8 axis components was confined to the prostate luminal epithelial cells in both normal and BPH tissues. However, these components were elevated in BPH-1 and primary explant cultures as compared to RWPE-1, NHPrE1, and BHPrE1 cells. Knockout of CXCR7 reduced IL-8, and CXCR1 expression by 4- to 10-fold and caused greater than or equal to 50% growth inhibition in BPH-1 cells. Low-dose OA + UA combination synergistically inhibited the growth of BPH-1 and BPH primary cultures. In the combination, the drug reduction indices for UA and OA were 16.4 and 7852, respectively, demonstrating that the combination was effective in inhibiting BPH-1 growth at significantly reduced doses of UA or OA alone.

CONCLUSION

The IL-8 axis is a promotor of BPH pathogenesis. Low-dose OA + UA combination inhibits BPH cell growth by inducing autophagy and reducing IL-8 axis expression in BPH-epithelial cells.

Amino Acids in Health and Endocrine Function

Dietary amino acids play an important role in maintaining health. Branched chain amino acids can adversely increase blood pressure whereas arginine and citrulline can reduce it. D-amino acids play important roles in several cell types including testis, the nervous system and adrenal glands. Several amino acids also can have dramatic effects on diabetes; branched chain amino acids, phenylalanine and tyrosine have been implicated while others, namely arginine and citrulline can improve outcomes. Leucine has been shown to play important roles in muscle primarily through the mTOR pathway though this effect does not translate across every population. Glutamine, arginine and D-aspartate also exert their muscle effects through mTOR. Relationships between amino acids and endocrine function include that of glucocorticoids, thyroid function, glucagon-like peptide 1 (GLP-1), ghrelin, insulin-like growth factor-1 (IGF-1) and leptin. Leucine, for example, can alleviate the effect of dexamethasone on muscle protein accretion. Interestingly, amino acid transporters play an important role in thyroid function. Several amino acids have been shown to increase GLP-1 levels in non-diabetics when administered orally. Similarly, several amino acids increase ghrelin levels in different species while cysteine can decrease it in mice. There is evidence to suggest that the arginine/NO pathway may be involved in modulating some of the effects of ghrelin on cells. In regard to IGF-1, branched chain amino acids can increase levels in adults while tryptophan and phenylalanine have been shown to increase levels in infants. Finally, leptin levels can be elevated by branched chain amino acids while restricting leucine in high fat diets can increase leptin sensitivity.

Effects of dietary supplementation in sport and exercise: a review of evidence on milk proteins and amino acids

Dietary supplements, especially protein, are used by athletes to achieve the exercise and training daily demands, and have been receiving research focus on their role regarding recovery and performance. Protein supplements are preferred over traditional protein sources because of their ease of availability and use. In addition to consuming a complete protein supplement, such as whey protein, the ingestion of a supplement containing only amino acids has been of interest for promoting skeletal muscle anabolism and high-quality weight loss. The aim of this study was to review the existing evidence on the effects of protein and amino acid supplementation on exercise. The preponderance of evidence suggests that protein supplementation, especially milk proteins, potentiate muscle protein synthesis, lean mass and exercise recovery. Unlike proteins, amino acids supplementation (branched-chain amino acids, glutamine or leucine) results from research are equivocal and are not warranted.

Leucine Improved Growth Performance, Muscle Growth, and Muscle Protein Deposition Through AKT/TOR and AKT/FOXO3a Signaling Pathways in Hybrid Catfish Pelteobagrus vachelli × Leiocassis longirostris

(1) Background: l-leucine (Leu) plays a positive role in regulating protein turnover in skeletal muscle in mammal. However, the molecular mechanism for the effects of Leu on muscle growth and protein deposition is not clearly demonstrated in fish. This study investigated the effects of dietary Leu on growth performance and muscle growth, protein synthesis, and degradation-related signaling pathways of hybrid catfish (Pelteobagrus vachelli♀ × Leiocassis longirostris♂). (2) Methods: A total of 630 hybrid catfish (23.19 ± 0.20 g) were fed 6 different experimental diets containing graded levels of Leu at 10.0 (control), 15.0, 20.0, 25.0, 30.0, 35.0, and 40.0 g Leu kg^-1 for 8 weeks. (3) Results: Results showed that dietary Leu increased percent weight gain (PWG), specific growth rate (SGR), FI (feed intake), feed efficiency (FE), protein efficiency ratio (PER), muscle fibers diameter, and muscle fibers density; up-regulated insulin-like growth factor I (IGF-I), insulin-like growth factor I receptor (IGF-IR), proliferating cell nuclear antigen (PCNA), myogenic regulation factors (MyoD, Myf5, MyoG, and Mrf4), and MyHC mRNA levels; increased muscle protein synthesis via regulating the AKT/TOR signaling pathway; and attenuated protein degradation via regulating the AKT/FOXO3a signaling pathway. (4) Conclusions: These results suggest that Leu has potential role to improve muscle growth and protein deposition in fish, which might be due to the regulation of IGF mRNA expression, muscle growth related gene, and protein synthesis and degradation-related signaling pathways. Based on the broken-line model, the Leu requirement of hybrid catfish (23.19-54.55 g) for PWG was estimated to be 28.10 g kg^-1 of the diet (73.04 g kg^-1 of dietary protein). These results will improve our understanding of the mechanisms responsible for muscle growth and protein deposition effects of Leu in fish.

Supplements with purported effects on muscle mass and strength

PURPOSE

Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear.

METHODS

This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength.

RESULTS

Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, β-Hydroxy-β-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid).

CONCLUSION

 In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.

Concurrent treatment with ursolic acid and low-intensity treadmill exercise improves muscle atrophy and related outcomes in rats

The objective of this study was to analyze the concurrent treatment effects of ursolic acid (UA) and low-intensity treadmill exercise and to confirm the effectiveness of UA as an exercise mimetic to safely improve muscle atrophy-related diseases using Sprague-Dawley (SD) rats with skeletal muscle atrophy. Significant muscle atrophy was induced in male SD rats through hind limb immobilization using casting for 10 days. The muscle atrophy-induced SD rats were group into four: SED, sedentary; UA, daily intraperitoneal UA injection, 5 mg/kg; EX, low-intensity (10–12 m/min, 0° grade) treadmill exercise; and UEX, daily intraperitoneal UA injection, 5 mg/kg, and low-intensity (10–12 m/min, 0° grade) treadmill exercise. After 8 weeks of treatment, endurance capacity was analyzed using a treadmill, and tissues were extracted for analysis of visceral fat mass, body weight, muscle mass, expression of muscle atrophy- and hypertrophy-related genes, and endurance capacity. Although the effects of body weight gain control, muscle mass increase, and endurance capacity improvement were inadequate in the UA group, significant results were confirmed in the UEX group. The UEX group had significantly reduced body weight and visceral fat, significantly improved mass of tibialis anterior and gastrocnemius muscles, and significantly decreased atrophy-related gene expression of MuRF1 and atrogin-1, but did not have significant change in hypertrophy-related gene expression of Akt and mTOR. The endurance capacity was significantly improved in the EX and UEX groups. These data suggest that concurrent treatment with low-intensity exercise and UA is effective for atrophy-related physical dysfunctions.

Ursolic acid in health and disease

Ursolic acid (UA) is a natural triterpene compound found in various fruits and vegetables. There is a growing interest in UA because of its beneficial effects, which include anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-carcinogenic effects. It exerts these effects in various tissues and organs: by suppressing nuclear factor-kappa B signaling in cancer cells, improving insulin signaling in adipose tissues, reducing the expression of markers of cardiac damage in the heart, decreasing inflammation and increasing the level of anti-oxidants in the brain, reducing apoptotic signaling and the level of oxidants in the liver, and reducing atrophy and increasing the expression levels of adenosine monophosphate-activated protein kinase and irisin in skeletal muscles. Moreover, UA can be used as an alternative medicine for the treatment and prevention of cancer, obesity/diabetes, cardiovascular disease, brain disease, liver disease, and muscle wasting (sarcopenia). In this review, we have summarized recent data on the beneficial effects and possible uses of UA in health and disease managements.

"Nutraceuticals" in relation to human skeletal muscle and exercise

Skeletal muscles have a fundamental role in locomotion and whole body metabolism, with muscle mass and quality being linked to improved health and even lifespan. Optimizing nutrition in combination with exercise is considered an established, effective ergogenic practice for athletic performance. Importantly, exercise and nutritional approaches also remain arguably the most effective countermeasure for muscle dysfunction associated with aging and numerous clinical conditions, e.g., cancer cachexia, COPD, and organ failure, via engendering favorable adaptations such as increased muscle mass and oxidative capacity. Therefore, it is important to consider the effects of established and novel effectors of muscle mass, function, and metabolism in relation to nutrition and exercise. To address this gap, in this review, we detail existing evidence surrounding the efficacy of a nonexhaustive list of macronutrient, micronutrient, and "nutraceutical" compounds alone and in combination with exercise in relation to skeletal muscle mass, metabolism (protein and fuel), and exercise performance (i.e., strength and endurance capacity). It has long been established that macronutrients have specific roles and impact upon protein metabolism and exercise performance, (i.e., protein positively influences muscle mass and protein metabolism), whereas carbohydrate and fat intakes can influence fuel metabolism and exercise performance. Regarding novel nutraceuticals, we show that the following ones in particular may have effects in relation to 1) muscle mass/protein metabolism: leucine, hydroxyl β-methylbutyrate, creatine, vitamin-D, ursolic acid, and phosphatidic acid; and 2) exercise performance: (i.e., strength or endurance capacity): hydroxyl β-methylbutyrate, carnitine, creatine, nitrates, and β-alanine.

Exercise increases mTOR signaling in brain regions involved in cognition and emotional behavior

Exercise can enhance learning and memory and produce resistance against stress-related psychiatric disorders such as depression and anxiety. In rats, these beneficial effects of exercise occur regardless of exercise controllability: both voluntary and forced wheel running produce stress-protective effects. The mechanisms underlying these beneficial effects of exercise remain unknown. The mammalian target of rapamycin (mTOR) is a translation regulator important for cell growth, proliferation, and survival. mTOR has been implicated in enhancing learning and memory as well as antidepressant effects. Moreover, mTOR is sensitive to exercise signals such as metabolic factors. The effects of exercise on mTOR signaling, however, remain unknown. The goal of the present study was to test the hypothesis that exercise, regardless of controllability, increases levels of phosphorylated mTOR (p-mTOR) in brain regions important for learning and emotional behavior. Rats were exposed to 6 weeks of either sedentary (locked wheel), voluntary, or forced wheel running conditions. At 6 weeks, rats were sacrificed during peak running and levels of p-mTOR were measured using immunohistochemistry. Overall, both voluntary and forced exercise increased p-mTOR-positive neurons in the medial prefrontal cortex, striatum, hippocampus, hypothalamus, and amygdala compared to locked wheel controls. Exercise, regardless of controllability, also increased numbers of p-mTOR-positive glia in the striatum, hippocampus, and amygdala. For both neurons and glia, the largest increase in p-mTOR positive cells was observed after voluntary running, with forced exercise causing a more modest increase. Interestingly, voluntary exercise preferentially increased p-mTOR in astrocytes (GFAP+), while forced running increased p-mTOR in microglia (CD11+) in the inferior dentate gyrus. Results suggest that mTOR signaling is sensitive to exercise, but subtle differences exist depending on exercise controllability. Increases in mTOR signaling could contribute to the beneficial effects of exercise on cognitive function and mental health.