Taohe Chengqi decoction alleviated metabolic-associated fatty liver disease by boosting branched chain amino acids catabolism in the skeletal muscles of type 2 diabetes mellitus.

OBJECTIVE: Metabolic-associated fatty liver disease (MAFLD) is the most prevalent liver disease, whereas type 2 diabetes mellitus (T2DM) is considered an independent risk factor for MAFLD incidence. Taohe Chengqi decoction (THCQ) is clinically prescribed for T2DM treatment; however, the hepatoprotective effect of THCQ against MAFLD is still unknown. This study intended to elucidate the therapeutic effect of THCQ on T2DM-associated MAFLD and to investigate the underlying mechanisms. METHODS: THCQ lyophilized powder was prepared and analyzed by UHPLC-MS/MS. A stable T2DM mouse model was established by high-fat diet (HFD) feeding combined with streptozotocin (STZ) injection. The T2DM mice were administered THCQ (2.5 g/kg or 5 g/kg) to explore the pharmacological effects of THCQ on T2DM-associated MAFLD. Liver tissue transcriptome was analyzed and the participatory roles of PPARα/γ pathways were verified both in vivo and in vitro. Serum metabolome analysis was used to explore the metabolome changes and skeletal muscle branched chain amino acid (BCAA) catabolic enzymes were further detected. Moreover, an AAV carrying BCKDHA shRNA was intramuscularly injected to verify the impact of THCQ on skeletal muscle BCAA catabolism and the potential therapeutic outcome on hepatic steatosis. RESULTS: THCQ improved hepatic steatosis in MAFLD. RNA-sequencing analysis showed dysregulation in the hepatic PPARγ-related fatty acid synthesis, while PPARα-dependent fatty acid oxidation was elevated following THCQ treatment. Interestingly, in vitro analyses of these findings showed that THCQ had minor effects on fatty acid oxidation and/or synthesis. The metabolomic study revealed that THCQ accelerated BCAA catabolism in the skeletal muscles, in which knockdown of the BCAA catabolic enzyme BCKDHA diminished the THCQ therapeutic effect on hepatic steatosis. CONCLUSION: This study highlighted the potential therapeutic effect of THCQ on hepatic steatosis in MALFD. THCQ upregulated fatty acid oxidation and reduced its synthesis via restoration of PPARα/γ pathways in HFD/STZ-induced T2DM mice, which is mediated through augmenting BCKDH activity and accelerating BCAA catabolism in the skeletal muscles. Overall, this study provided in-depth clues for "skeletal muscles-liver communication" in the therapeutic effect of THCQ against hepatic steatosis. These findings suggested THCQ might be a potential candidate against T2DM-associated MAFLD.

Walking exercise through smartphone application plus branched-chain amino acid supplementation benefits skeletal muscle mass and strength in liver cirrhosis: A prospective control trial.

INTRODUCTION AND OBJECTIVES: Whether a combination of exercise and branched-chain amino acid (BCAA) supplementation was more beneficial than those given alone in sarcopenia related to liver cirrhosis (LC) is unknown. Widely used smartphone applications provide continuous and easily expandable management of chronic liver disease (CLD). This study is to investigate the effects of unsupervised walking exercise using WeChat combined with BCAA supplementation on skeletal muscle mass and strength in LC. MATERIALS AND METHODS: The 127 LC patients of Child-Pugh A/B were assigned to group A (BCAA supplements, n=42), group B (walking exercise, n=43) and group C (walking exercise plus BCAA supplements, n=42). Laboratory data, average daily steps, serum BCAA, skeletal muscle mass index (SMI) and grip strength were analyzed pre- and 3 months after interventions. RESULTS: Of the 124 patients who completed interventions, albumin and daily steps were significantly increased in all groups (p=0.0001). Post-intervention BCAA were significantly elevated in group A (A vs B, p=0.001) and C (C vs B, p=0.012;). While post-intervention daily steps in group B (B vs A, p=0.0001) and C (C vs A, p=0.0001) were higher. Grip strength (C vs A, p=0.020; C vs B, p=0.036) and SMI (C vs A, p=0.035; C vs B, p=0.012) were increased in group C. Prevalence of sarcopenia was significantly decreased in group C (p=0.015). CONCLUSIONS: A combination of unsupervised walking exercise using smartphone applications and BCAA supplementation might be an effective and safe treatment for cirrhosis patients with Child-Pugh A/B to improve skeletal muscle mass and strength or to prevent progress of sarcopenia.

The effects of arginine and branched-chain amino acid supplementation to reduced-protein diet on intestinal health, cecal short-chain fatty acid profiles, and immune response in broiler chickens challenged with Eimeria spp.

We investigated the effects of supplementing arginine (Arg) and branched-chain amino acids (BCAA) in broilers fed reduced-protein diets and challenged with Eimeria spp. All birds were fed the same starter diet meeting Cobb 500 nutrient specifications from d 1 to 9. Four grower diets: positive control (PC) with 20.0% crude protein (CP); reduced-protein negative control (NC) with 17.5% CP; or NC supplemented with Arg or BCAA at 50% above recommendations (ARG or BCAA) were fed to the birds from d 9 to 28. Birds were allocated in a 2 × 4 factorial arrangement (4 diets, each with or without challenge), with 8 replicates per treatment. On d 14, the challenge groups were orally gavaged with mixed Eimeria spp. Intestinal permeability was higher (P < 0.05) in NC than PC, whereas the permeability of ARG and BCAA groups did not differ significantly from PC. On d 28, a significant interaction (P < 0.01) was observed in CD8+: CD4+ ratios in cecal tonsils (CT), Eimeria challenge increased the ratios in all groups except for the ARG group. On d 21, a significant interaction was found for CD4+CD25+ percentages in CT (P < 0.01) that Eimeria challenge increased the percentages only in PC and NC groups. On d 21 and 28, significant interactions (P < 0.01) were found for macrophage nitric oxide (NO) production. In nonchallenged birds, NO was higher in the ARG group than other groups, but in challenged birds, NO was higher in both ARG and BCAA groups. On d 21, a significant interaction was found for bile anticoccidial IgA concentrations (P < 0.05) that Eimeria challenge increased IgA only in NC and ARG groups. The results suggest that a reduced-protein diet exacerbates the impact of the Eimeria challenge on intestinal integrity, but this could be mitigated by Arg and BCAA supplementations. Arginine and BCAA supplementations in reduced-protein diets could be beneficial for broilers against Eimeria infection by enhancing the immune responses. The beneficial effects of Arg supplementation tended to be more pronounced compared to BCAA supplementation.

Comparison of an Antioxidant Source and Antioxidant Plus BCAA on Athletic Performance and Post Exercise Recovery of Horses.

Antioxidant supplementation decreases postexercise oxidative stress but could also decrease muscle protein synthesis. This study compared the effects of three diets: low antioxidant (control, CON), high antioxidant (AO), and branched-chain amino acid high antioxidant (BCAO) supplementation on postexercise protein synthesis and oxidative stress. We hypothesized that supplementing antioxidants with branched-chain amino acids(BCAA) would reduce oxidative stress without hindering muscle protein synthesis. Eighteen mixed-breed polo horses (11 mares and 7 geldings, with age range between 5 and 18 years, were on CON diet for 30 days (from day -45 until day 0) and then were assigned to one of the treatments after the first lactate threshold test (day 0, LT). LT were also conducted on days 15 and 30 of supplemenation. Oxidative stress was assessed by measuring blood glutathione peroxidase, superoxide dismutase, and malondialdehyde concentrations before 2 and 4 hours after each LT. Muscle biopsies were taken before and 4 hours after each LT and analyzed for gene expression of protein synthesis by RTqPCR. Data were analyzed by ANOVA and compared by least-square means. A reduction in oxidative stress occurred over time (P < .05), from day 0 to day 30. An up-regulation in the abundance of muscle protein mRNA transcripts was found for CD36, CPT1, PDK4, MYF5, and MYOG (P < .05) after all lactate threshold tests, without a treatment effect. A treatment-by-exercise effect was observed for MYOD1 (P = .0041). Transcript abundance was upregulated in AO samples post exercise compared to other treatments. MYF6 exhibited a time-by-treatment effect (P = .045), where abundance increased more in AO samples from day 0 to day 15 and 30 compared to other treatments. Transcript abundance for metabolic and myogenic genes was upregulated in post exercise muscle samples with no advantage from supplementation of antioxidants with branched-chain amino acids compared to antioxidants alone.

Omega-3 fatty acids enhance the beneficial effect of BCAA supplementation on muscle function following eccentric contractions.

Background: This study investigated the combined effect of branched-chain amino acids (BCAA) and fish oil (FO) on muscle damage caused by eccentric contractions (ECCs) of the elbow flexors, with a special focus on muscular function. Methods: Twenty-nine untrained male participants were enrolled in this double-blind, placebo-controlled, parallel study. The participants were randomly assigned to the placebo (PL) group (n = 9), BCAA supplement group (n = 10), and BCAA+FO supplement group (n = 10). The BCAA+FO group consumed eicosapentaenoic acid (EPA) 600 mg and docosahexaenoic acid (DHA) 260 mg per day for 8 weeks, while the BCAA and BCAA+FO groups consumed 9.6 g per day for 3 days prior to and until 5 days after ECCs. Participants performed six sets of 10 ECCs at 100% maximal voluntary contraction (MVC) using dumbbells. Changes in MVC torque, range of motion (ROM), muscle soreness using visual analog scales, upper circumference, muscle thickness, echo intensity, and serum creatine kinase (CK) were assessed before, immediately after, and 1, 2, 3, and 5 days after ECCs. Results: The MVC torque was significantly higher in the BCAA+FO group than in the PL group immediately after ECCs (p < 0.05) but not in the BCAA group. Both BCAA and BCAA+FO groups showed greater ROM and lower muscle soreness than the PL group (p < 0.05). CK was significantly lower in the BCAA group than in the PL group at 5 days after ECCs (p < 0.05). Conclusions: This study reveals that supplementation with BCAA and FO may favorably impact immediate recovery of peak torque production. Alternatively, in comparison to PL group, BCAA supplementation favorably reduces creatine kinase.

Neuroinflammatory responses following zinc or branched-chain amino acids supplementation in obese rats.

The excessive production of pro-inflammatory mediators, characteristic of obesity, leads to neuroinflammation. Zinc (Zn) and the branched-chain amino acids (BCAA) are supplements known for their immunomodulatory properties. Our goal was to evaluate if Zn or BCAA supplementation can affect long-term recognition memory and neuroinflammatory parameters of obese rats after a high-fat diet (HFD). Three-month-old Wistar rats were divided into six groups: Standard diet (SD) + vehicle; SD + Zn; SD + BCAA; High-fat diet (HFD) + vehicle; HFD + Zn; and HFD + BCAA. Diets were administrated for 19 weeks, Zn (1,2 mg/kg/day) or BCAA (750 mg/kg/day) supplementation was conducted in the last 4 weeks. Long-term recognition memory was evaluated by the novel object recognition test. IL-1ß immunoreactivity in the cortex and hippocampus, and IL-6 levels in the cortex tissue were assessed. Astrogliosis were evaluated through GFAP + cell count and morphological analysis (Sholl Method). Zn supplementation improved object recognition memory in HFD-fed rats, which was not observed following BCAA supplementation. The levels of IL-6 in the cerebral cortex were higher after HFD, which was not diminished after neither supplementation. Obesity also led to increased IL-1ß immunoreactivity in the cerebral cortex and hippocampus, which was reduced by Zn. BCAA supplementation also diminished IL-1ß immunoreactivity, but only in the hippocampus. We also showed that astrocyte reactivity caused by HFD is area-dependent, being the cerebral cortex more susceptible to the diet. Even though BCAA and Zn can affect IL-1ß immunoreactivity and astrocyte morphology, only Zn improved memory. Future studies are needed to clarify the pathways by which Zn improves cognition in obesity.

Protective Effect of Amino Acids on the Muscle Injury of Aerobics Athletes after Endurance Exercise Based on CT Images.

During the training process, the aerobics athletes gradually increase their technical movements, the appreciation of the movements has been gradually improved, and the injuries of the athletes themselves have also gradually become serious. Based on CT image analysis, we study the protective effect of amino acids on aerobics athletes' muscle injury after endurance exercise. There are three major substance metabolism disorders in patients with muscle sclerosis, which are mainly manifested as decreased glucose tolerance and insulin resistance. Some patients develop muscle-derived diabetes. At the same time, the synthesis of lipids such as cholesterol and apolipoproteins decreases, the production of ketone bodies increases and the body uses more ketones for energy. The BCAA/AAA factor refers to the branched-chain amino acid/aromatic amino acid (BCAA/AAA) value. In amino acid metabolism, plasma albumin decreased significantly, the ratio of amino acids was unbalanced, and BCAA/AAA decreased, which was more likely to induce muscular encephalopathy. Using computer tomography (CT) to study the protective effect of amino acids on muscle injury, 32 aerobics athletes were randomly divided into an intervention group (Ig) and a control group (CG), each with 16 people. After 64-slice spiral CT scanning of muscles and three-dimensional reconstruction, the intervention group and the control group participated in aerobic endurance training 3 weeks in advance to establish a muscle microinjury model. The intervention group took the preprepared BCAA, while the control group did not take it. After three weeks of training, there will be one hour and three hours of aerobics competition. We need to detect changes in blood glucose (BS), creatine kinase (SCK), lactate dehydrogenase (LD), alanine (ALA), and alanine aminotransferase (AA) before and after exercise and 1 hour after exercise and record AVS athletes' pain analysis table. We successfully established the muscle injury model, letting all athletes' VAS score in 6-8 points; after 1 hour of exercise, the measurement results were the same as those of 2 hours. Therefore, after endurance training, the blood glucose content of the intervention group gradually decreased and returned to the original level after 2 hours of exercise, while the control group was lower than the level of exercise after 2 hours of exercise; the content of alanine in the two groups decreased more after 2 hours of exercise; the results of serum creatine kinase in the intervention group were higher than those in the control group after exercise. In the intervention group, lactate dehydrogenase increased rapidly at 2 hours after exercise; the alanine aminotransferase in the intervention group increased after exercise, but there was no significant change in the control group. It is also concluded that the longer the exercise time and the more energy consumption, the more effective the branched-chain amino acids supplement will be. The obtained imaging data can provide a more intuitive and accurate basis for the scientific selection of athletes, and amino acids can promote the synthesis of hormones, accelerate the synthesis of proteins and other products, reduce the content of creatine kinase in the blood, and protect the rapid recovery of muscle damage.

Effects of branched-chain amino acids on immune status of young racing horses.

High-intensity exercise and competition are associated with depressed immune function. Young horses, which participate in high-intensity exercise and competitions, are at increased risk for the development of infectious disease due to depression of immune function. The effects of branched-chain amino acid (BCAA) supplementation on the immune status of young racing horses were evaluated, determining whether BCAA might help to avoid or reduce immune suppression during exercise and competitions. Twenty horses (10 male and 10 female) were treated with BCAA supplementation; another twenty untreated horses (10 male and 10 female) constituted control group. Peripheral blood was collected from each animal and evaluated for lymphocyte subsets, phagocytosis analysis of monocytes and granulocytes, lymphocyte proliferative response, and expression of cytokine-encoding messenger ribonucleic acids (mRNAs). The numbers of CD4+, CD8+, and major histocompatibility complex (MHC) class II+ cells in females of the treated group were significantly higher than those in females of the control group. The lymphocyte proliferative response in female of the treated group also was significantly higher than that in females of the control group. In addition, expression of mRNAs encoding interleukin-1ß (IL-1ß) and interferon-γ (IFN-γ) in females of the treated group was significantly higher than that in females of the control group. There were no significant differences between males of the treated and control groups. The results of this study indicated the positive effects of BCAA supplementation in counteracting immunosuppression in young female racing horses during and following high-intensity exercise.

Does Branched-Chain Amino Acids (BCAAs) Supplementation Attenuate Muscle Damage Markers and Soreness after Resistance Exercise in Trained Males? A Meta-Analysis of Randomized Controlled Trials.

Previous studies have reported the positive effects of branched-chain amino acids (BCAAs) supplementation on lowering plasma markers of muscle damage and subjective soreness after resistance exercise. However, a variety of factors can potentially moderate its efficacy. This meta-analysis aimed to summarize the evidence regarding the effect of BCAAs supplementation on plasma muscle damage markers and soreness after resistance exercise in only trained males, by considering the plasma lactate dehydrogenase (LDH) and creatine kinase (CK). Randomized controlled trials were identified through a computerized literature search for the period 2010-2020. The pooled data were analyzed with the random-effects model and heterogeneity using I2. Cochrane Collaboration tools was used for the assessment of risk of bias. Nine studies met the inclusion criteria. A positive effect was found for CK at <24, 24, and 48 h after exercise and for muscle soreness at <24 h only. However, the positive effect was not evident for plasma LDH at any follow-up time. Different outcomes for post-exercise responses may suggest that BCAAs supplementation can attenuate muscle damage and ameliorate muscle soreness after resistance exercise in trained males.

Leucine, but not isoleucine or valine, affects serum lipid profiles and browning of WAT in mice.

Branched chain amino acids (BCAA), especially leucine (Leu), have been reported to decrease fat deposition. However, opposite effects of BCAA on lipid metabolism have been observed. To determine the role of BCAA in lipid metabolism, an amino acid-defined diet was formulated and C57BL/6J mice were assigned into the following groups: amino acid-defined control diet and control diet supplemented with Leu, isoleucine, or valine. Nitrogen was balanced by proportionally mixed amino acids except BCAA. Results showed that dietary Leu supplementation significantly increased the levels of serum triglycerides, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and urea nitrogen. Metabolomics showed that biosynthesis of unsaturated fatty acids was altered by Leu supplementation. Leu treatment up-regulated the expression of genes related to fat synthesis and down-regulated the expression of genes related to fatty acid synthesis. Furthermore, the genes and proteins of selective markers involved in browning of white adipose tissue (WAT) were up-regulated by dietary supplementation with Leu. This study indicated that dietary supplementation with Leu, but not isoleucine or valine, significantly affected lipid metabolism by regulating lipid metabolism-related genes and serum fatty acid concentration, providing a new tool in the management of obesity and metabolic disorders.

Isolated Leucine and Branched-Chain Amino Acid Supplementation for Enhancing Muscular Strength and Hypertrophy: A Narrative Review.

Branched-chain amino acids (BCAA) are one of the most popular sports supplements, marketed under the premise that they enhance muscular adaptations. Despite their prevalent consumption among athletes and the general public, the efficacy of BCAA has been an ongoing source of controversy in the sports nutrition field. Early support for BCAA supplementation was derived from extrapolation of mechanistic data on their role in muscle protein metabolism. Of the three BCAA, leucine has received the most attention because of its ability to stimulate the initial acute anabolic response. However, a substantial body of both acute and longitudinal research has now accumulated on the topic, affording the ability to scrutinize the effects of BCAA and leucine from a practical standpoint. This article aims to critically review the current literature and draw evidence-based conclusions about the putative benefits of BCAA or leucine supplementation on muscle strength and hypertrophy as well as illuminate gaps in the literature that warrant future study.

Effects of different branched-chain amino acids supplementation protocols on the inflammatory response of LPS-stimulated RAW 264.7 macrophages.

Although branched-chain amino acids (BCAA) are commonly used as a strategy to recover nutritional status of critically ill patients, recent findings on their role as immunonutrients have been associated with unfavorable outcomes, especially in obese patients. The present study aimed to explore the effects of different BCAA supplementation protocols in the inflammatory response of LPS-stimulated RAW 264.7 macrophages. Cell cultures were divided into five groups, with and without BCAA supplementation, (2 mmol/L of each amino acid). Then, cell cultures followed three different treatment protocols, consisting of a pretreatment (PT), an acute treatment (AT), and a chronic treatment (CT) with BCAA and LPS stimulation (1 µg/mL). Cell viability was analyzed by MTT assay, NO production was assessed by the Griess reaction and IL-6, IL-10, TNF-α and PGE2 synthesis, was evaluated by ELISA. BCAA significantly increased cell viability in AT and CT protocols, and NO and IL-10 synthesis in all treatment protocols. IL-6 synthesis was only increased in PT and CT protocols. TNF-α and PGE2 synthesis were not altered in any of the protocols and groups. BCAA supplementation was able to increase both pro and anti-inflammatory mediators synthesis by RAW 264.7 macrophages, which was influenced by the protocol applied. Moreover, these parameters were significantly increased by isoleucine supplementation, highlighting a potential research field for future studies.

Excessive ROS production and enhanced autophagy contribute to myocardial injury induced by branched-chain amino acids: Roles for the AMPK-ULK1 signaling pathway and α7nAChR.

BACKGROUNDS AND AIMS: Leucine, isoleucine, and valine are diet derived and essential amino acids that are termed branched-chain amino acids (BCAA). BCAA are widely used as dietary supplements to boost muscle growth and enhance exercise performance. However, the effects of BCAA on myocardial function are largely unknown. This study was designed to investigate whether BCAA affect heart function and, if so, to further explore the underlying molecular basis for the observed effects. METHODS AND RESULTS: C57BL/6J mice were randomly divided into two groups, the control group received solvent (water) and the BCAA group received 2% BCAA dissolved in water, for a successive period of 12 weeks. Compared with control, BCAA treatment significantly increased water consumption without changing body weight or diet consumption; heart tissue BCAA levels were increased, markers representative of myocardial injury in heart tissue including c-reactive protein and cardiac muscle troponin were increased ; and creatine kinase, creatine kinase-MB, and lactate dehydrogenase were increased in serum; severe myocardial fibrosis was observed by Masson staining, which was accompanied by increased reactive oxygen species (ROS) production and decreased superoxide dismutase activity in heart tissue; both p-AMPK and p-ULK1 were significantly increased as was autophagy, judged by the presence of LC3 by western blotting and immunofluorescence, increased numbers of autophagosomes were found by transmission electron microscopy in the BCAA group. In vitro, 20 mmol/L BCAA significantly decreased cell viability and increased the production of ROS, as well as the expression of p-AMPK/AMPK and p-ULK1/ULK1 in cultured H9C2 cells. Treatment with the ROS scavenger N-acetyl-L-cysteine (NAC) improved cell viability and reversed ROS changes. Decreased H9C2 cell viability induced with 20 mmol/L BCAA was reversed by either blocking AMPK or inhibition of ULK1. Furthermore, blocking AMPK significantly decreased p-ULK1/ULK1, while inhibition of ULK1 reversed the enhanced expression of LC3-II/LC3-I induced by BCAA. Excessive ROS production and decreased cell viability induced by BCAA were further confirmed in primary cultured murine cardiomyocytes. Pharmacological activation of α7nAChR with PNU-282987 attenuated BCAA-induced injury in primary murine cardiomyocytes. However, this compound failed to suppress BCAA activation of AMPK and autophagy (LC3-II/I ratio). CONCLUSION: These results provide the first evidence that treatment of mice with BCAA induced myocardial injury by triggering excessive ROS production and by enhancing AMPK-ULK1 pathway-dependent autophagy. These findings suggested that inhibition of either ROS production or autophagy may alleviate myocardial injury induced by BCAA.

Intragastric administration of leucine and isoleucine does not reduce the glycaemic response to, or slow gastric emptying of, a carbohydrate-containing drink in type 2 diabetes.

AIMS: In healthy individuals, intragastric administration of the branched-chain amino acids, leucine and isoleucine, diminishes the glycaemic response to a mixed-nutrient drink, apparently by stimulating insulin and slowing gastric emptying, respectively. This study aimed to evaluate the effects of leucine and isoleucine on postprandial glycaemia and gastric emptying in type-2 diabetes mellitus (T2D). METHODS: 14 males with T2D received, on 3 separate occasions, in double-blind, randomised fashion, either 10 g leucine, 10 g isoleucine or control, intragastrically 30 min before a mixed-nutrient drink (500 kcal; 74 g carbohydrates, 18 g protein, 15 g fat). Plasma glucose, insulin and glucagon were measured from 30 min pre- until 120 min post-drink. Gastric emptying of the drink was also measured. RESULTS: Leucine and isoleucine stimulated insulin, both before and after the drink (all P < 0.05; peak (mU/L): control: 70 ± 15; leucine: 88 ± 17; isoleucine: 74 ± 15). Isoleucine stimulated (P < 0.05), and leucine tended to stimulate (P = 0.078), glucagon before the drink, and isoleucine stimulated glucagon post-drink (P = 0.031; peak (pg/mL): control: 62 ± 5; leucine: 70 ± 9; isoleucine: 69 ± 6). Neither amino acid affected gastric emptying or plasma glucose (peak (mmol/L): control: 12.0 ± 0.5; leucine: 12.5 ± 0.7; isoleucine: 12.0 ± 0.6). CONCLUSIONS: In contrast to health, in T2D, leucine and isoleucine, administered intragastrically in a dose of 10 g, do not lower the glycaemic response to a mixed-nutrient drink. This finding argues against a role for 'preloads' of either leucine or isoleucine in the management of T2D.

Short-term branched-chain amino acid supplementation does not enhance vertical jump in professional volleyball players. A double-blind, controlled, randomized study.

INTRODUCTION: To the best of the authors' knowledge, no previous studies have described the effect of branched-chain amino acids (BCAA) on vertical performance during a week in professional volleyball players. This study assessed BCAA supplementation for a week, aiming to improve vertical jump performance in male professional volleyball players. Twelve male volleyballers were randomly assigned to a BCAA group (n = 6) or a control group (n = 6). The BCAA group ingested 21 g over a week, 7 g per day on Monday, Wednesday, and Friday, before a volleyball training session, while the control group drank a placebo drink. Participants performed 8 maximal countermovement jumps (CMJ); the 3 CMJs on Monday and Wednesday were evaluated after warm-up, after plyometric training, and at the end of the training session; and the 2 CMJs on Friday were evaluated after warm-up, and at the end of the training session. Compared with baseline, no significant differences in CMJ over the week were observed in BCAA or control group, neither between groups. The results indicated that 21 g of BCAA supplementation over a week did not improve vertical jump performance in professional volleyball players.

INTRODUCCIÓN: Hasta donde los autores saben, no se han descrito estudios previos sobre el efecto de los aminoácidos ramificados (BCAA) en el rendimiento vertical durante una semana en jugadores de voleibol profesionales. Este artículo estudió la suplementación de BCAA durante una semana con el objeto de mejorar el rendimiento del salto vertical en jugadores de voleibol profesionales masculinos. Doce jugadores de voleibol masculinos se asignaron aleatoriamente a un grupo con BCAA (n = 6) o a un grupo de control (n = 6). El grupo con BCAA ingirió 21 g en una semana, 7 g por día los lunes, miércoles y viernes antes de la sesión de entrenamiento de voleibol, mientras que el grupo de control bebió una bebida placebo. Los participantes realizaron 8 saltos máximos de contramovimiento (CMJ); los 3 CMJ de lunes y miércoles se evaluaron después del calentamiento y del entrenamiento pliométrico, y al final de la sesión de entrenamiento; los 2 CMJ del viernes se evaluaron después del calentamiento y al final de la sesión de entrenamiento. En comparación con el valor inicial, no se observaron diferencias significativas en los CMJ a lo largo de la semana, ni en el grupo BCAA ni en el grupo control, tampoco hubo diferencias entre grupos. Los resultados indicaron que 21 g de BCAA administrados durante una semana no mejoraron el rendimiento del salto vertical en jugadores de voleibol profesionales.

Complete neural stem cell (NSC) neuronal differentiation requires a branched chain amino acids-induced persistent metabolic shift towards energy metabolism.

Neural stem cell (NSC) neuronal differentiation requires a metabolic shift towards oxidative phosphorylation. We now show that a branched-chain amino acids-driven, persistent metabolic shift toward energy metabolism is required for full neuronal maturation. We increased energy metabolism of differentiating neurons derived both from murine NSCs and human induced pluripotent stem cells (iPSCs) by supplementing the cell culture medium with a mixture composed of branched-chain amino acids, essential amino acids, TCA cycle precursors and co-factors. We found that treated differentiating neuronal cells with enhanced energy metabolism increased: i) total dendritic length; ii) the mean number of branches and iii) the number and maturation of the dendritic spines. Furthermore, neuronal spines in treated neurons appeared more stable with stubby and mushroom phenotype and with increased expression of molecules involved in synapse formation. Treated neurons modified their mitochondrial dynamics increasing the mitochondrial fusion and, consistently with the increase of cellular ATP content, they activated cellular mTORC1 dependent p70S6 K1 anabolism. Global transcriptomic analysis further revealed that treated neurons induce Nrf2 mediated gene expression. This was correlated with a functional increase in the Reactive Oxygen Species (ROS) scavenging mechanisms. In conclusion, persistent branched-chain amino acids-driven metabolic shift toward energy metabolism enhanced neuronal differentiation and antioxidant defences. These findings offer new opportunities to pharmacologically modulate NSC neuronal differentiation and to develop effective strategies for treating neurodegenerative diseases.

Branched-Chain Amino Acids Exacerbate Obesity-Related Hepatic Glucose and Lipid Metabolic Disorders via Attenuating Akt2 Signaling.

Branched chain amino acids (BCAAs) are associated with the progression of obesity-related metabolic disorders, including type 2 diabetes and nonalcoholic fatty liver disease. However, whether BCAAs disrupt the homeostasis of hepatic glucose and lipid metabolism remains unknown. In this study, we observed that BCAAs supplementation significantly reduced high-fat (HF) diet-induced hepatic lipid accumulation while increasing the plasma lipid levels and promoting muscular and renal lipid accumulation. Further studies demonstrated that BCAAs supplementation significantly increased hepatic gluconeogenesis and suppressed hepatic lipogenesis in HF diet-induced obese (DIO) mice. These phenotypes resulted from severe attenuation of Akt2 signaling via mTORC1- and mTORC2-dependent pathways. BCAAs/branched-chain α-keto acids (BCKAs) chronically suppressed Akt2 activation through mTORC1 and mTORC2 signaling and promoted Akt2 ubiquitin-proteasome-dependent degradation through the mTORC2 pathway. Moreover, the E3 ligase Mul1 played an essential role in BCAAs/BCKAs-mTORC2-induced Akt2 ubiquitin-dependent degradation. We also demonstrated that BCAAs inhibited hepatic lipogenesis by blocking Akt2/SREBP1/INSIG2a signaling and increased hepatic glycogenesis by regulating Akt2/Foxo1 signaling. Collectively, these data demonstrate that in DIO mice, BCAAs supplementation resulted in serious hepatic metabolic disorder and severe liver insulin resistance: insulin failed to not only suppress gluconeogenesis but also activate lipogenesis. Intervening BCAA metabolism is a potential therapeutic target for severe insulin-resistant disease.

Effects of a commercially available branched-chain amino acid-alanine-carbohydrate-based sports supplement on perceived exertion and performance in high intensity endurance cycling tests.

BACKGROUND: Sports nutritional supplements containing branched-chain amino acids (BCAA) have been widely reported to improve psychological and biological aspects connected to central fatigue and performance in endurance exercise, although the topic is still open to debate. The aim of the present study was to determine whether the intake of a commercially available BCAA-based supplement, taken according to the manufacturer's recommendations, could affect the rating of perceived exertion (RPE) and performance indexes at the beginning (1d) and end of a 9-week (9w) scheduled high intensity interval training program, with an experimental approach integrating the determination of psychometric, performance, metabolic and blood biochemical parameters. METHODS: This was a randomized double-blind placebo-controlled study. Thirty-two untrained, healthy young adults (20 males and 12 female) were enrolled. A high-intensity endurance cycling (HIEC) test was used to induce fatigue in the participants: HIEC consisted in ten 90 s sprints interspersed by ten 3 min recovery phases and followed by a final step time to exhaustion was used. In parallel with RPE, haematological values (creatine kinase, alanine, BCAA, tryptophan, ammonia and glucose levels), and performance indexes (maximal oxygen consumption - VO2max, power associated with lactate thresholds - WLT1, WLT2 and time to exhaustion - TTE) were assessed. All subject took the supplement (13.2 g of carbohydrates; 3.2 g of BCAA and 1.6 g of L-alanine per dose) or placebo before each test and training session. Dietary habits and training load were monitored during the entire training period. RESULTS: The administration of the supplement (SU) at 1d reduced RPE by 9% during the recovery phase, as compared to the placebo (PL); at 9w the RPE scores were reduced by 13 and 21% during the sprint and recovery phase, respectively; at 9w, prolonged supplement intake also improved TTE and TRIMP. SU intake invariably promoted a rapid increase (within 1 h) of BCAA serum blood levels and prevented the post-HIEC tryptophan: BCAA ratio increase found in the PL group, at both 1d and 9w. There was no difference in dietary habits between groups and those habits did not change over time; no difference in glycemia was found between SU and PL. VO2max, WLT1 and WLT2 values improved over time, but were unaffected by supplement intake. CONCLUSIONS: On the whole, these results suggest that i) the intake of the BCAA-based commercially available supplement used in this study reduces RPE as a likely consequence of an improvement in the serum tryptophan: BCAA ratio; ii) over time, reduced RPE allows subjects to sustain higher workloads, leading to increased TRIMP and TTE.

Effects of Citrulline Supplementation on Exercise Performance in Humans: A Review of the Current Literature.

Gonzalez, AM and Trexler, ET. Effects of citrulline supplementation on exercise performance in humans: A review of the current literature. J Strength Cond Res 34(5): 1480-1495, 2020-L-citrulline, a nonessential amino acid found primarily in watermelon, has recently garnered much attention for its potential to augment L-arginine bioavailability, nitric oxide production, and exercise performance. Over the past decade, L-citrulline has received considerable scientific attention examining potentially ergogenic properties for both aerobic and anaerobic exercise performance. Thus, the purpose of this article is to summarize the theoretical rationale behind L-citrulline supplementation and to comprehensively review the available scientific evidence assessing the potential ergogenic value of L-citrulline supplementation on vascular function and exercise performance in humans. In addition, research that has investigated the potential synergistic effects of L-citrulline with other dietary ingredients (e.g., arginine, antioxidants, nitrates, and branched-chain amino acids) is reviewed. Oral L-citrulline and citrulline malate supplementation have shown to increase plasma citrulline and arginine concentrations, along with total nitrate and nitrite concentrations. Although blood flow enhancement is a proposed mechanism for the ergogenic potential of L-citrulline, evidence supporting acute improvements in vasodilation and skeletal muscle tissue perfusion after supplementation is scarce and inconsistent. Nevertheless, several studies have reported that L-citrulline supplementation can enhance exercise performance and recovery. Given the positive effects observed from some investigations, future studies should continue to investigate the effects of both acute and chronic supplementation with L-citrulline and citrulline malate on markers of blood flow and exercise performance and should seek to elucidate the mechanism underlying such effects.

Changes in human gut microbiota composition are linked to the energy metabolic switch during 10 d of Buchinger fasting.

Fasting is increasingly popular to manage metabolic and inflammatory diseases. Despite the role that the human gut microbiota plays in health and diseases, little is known about its composition and functional capacity during prolonged fasting when the external nutrient supply is reduced or suppressed. We analysed the effects of a 10-d periodic fasting on the faecal microbiota of fifteen healthy men. Participants fasted according to the peer-reviewed Buchinger fasting guidelines, which involve a daily energy intake of about 1046 kJ (250 kcal) and an enema every 2 d. Serum biochemistry confirmed the metabolic switch from carbohydrates to fatty acids and ketones. Emotional and physical well-being were enhanced. Faecal 16S rRNA gene amplicon sequencing showed that fasting caused a decrease in the abundance of bacteria known to degrade dietary polysaccharides such as Lachnospiraceae and Ruminococcaceae. There was a concomitant increase in Bacteroidetes and Proteobacteria (Escherichia coli and Bilophila wadsworthia), known to use host-derived energy substrates. Changes in taxa abundance were associated with serum glucose and faecal branched-chain amino acids (BCAA), suggesting that fasting-induced changes in the gut microbiota are associated with host energy metabolism. These effects were reversed after 3 months. SCFA levels were unchanged at the end of the fasting. We also monitored intestinal permeability and inflammatory status. IL-6, IL-10, interferon γ and TNFα levels increased when food was reintroduced, suggesting a reactivation of the postprandial immune response. We suggest that changes in the gut microbiota are part of the physiological adaptations to a 10-d periodic fasting, potentially influencing its beneficial health effects.