Mixture Of Branched-chain Amino Acids Research Articles

Branched-chain amino acids regulate intracellular protein turnover in porcine mammary epithelial cells.

Dietary supplementation with branched-chain amino acids (BCAAs) to lactating sows has been reported to enhance their milk production, but the underlying mechanisms remain largely unknown. This study was conducted with porcine mammary epithelial cells (PMECs) to test the hypothesis that individual BCAAs or their mixture stimulates protein synthesis and inhibit proteolysis in PMECs. Cells were cultured at 37°C in customizedDulbecco's modified Eagle medium containing 5mmol/L D-glucose, 1mmol/L L-phenylalanine, L-[ring-2,4-3H]phenylalanine, 0.1 (control), 0.25, 0.5, 1, or 2mmol/L L-leucine, L-isoleucine or L-valine or an equimolar mixture of the three BCAAs. The culture medium also contained physiological concentrations of other amino acids found in the plasma of lactating sows. Proliferation, protein synthesis, proteolysis, β-casein production, the mechanistic target of rapamycin (mTOR) signaling, and the ubiquitin-proteasome pathway were determined for PMECs. Cell proliferation and abundances of phosphorylated mTOR, eukaryotic translation initiation factor 4E-binding protein 1, and ribosomal protein S6 kinase β-1 proteins increased (P < 0.05), but abundances of ubiquitinated protein and 20S proteasome decreased (P < 0.05) when extracellular concentrations of L-leucine, L-isoleucine, L-valine, or an equimolar mixture of BCAAs were increased from 0.1 to 2mmol/L. Compared with the control, 0.25, 0.5, 1 or 2mmol/L BCAAs enhanced (P < 0.01) protein (including β-casein) synthesis, while decreasing (P < 0.05) proteolysis in PMECs in a dose-dependent manner. Collectively, our results indicate that physiological concentrations of BCAAs regulate protein turnover in mammary epithelial cells to favor net protein synthesis through stimulating the mTOR signaling pathway and inhibiting the ubiquitin-proteasome pathway.

Changes in plasma concentration of kynurenine following intake of branched-chain amino acids are not caused by alterations in muscle kynurenine metabolism.

Administration of branched-chain amino acids (BCAA) has been suggested to enhance mitochondrial biogenesis, including levels of PGC-1α, which may, in turn, alter kynurenine metabolism. Ten healthy subjects performed 60 min of dynamic one-leg exercise at ∼70% of Wmax on two occasions. They were in random order supplied either a mixture of BCAA or flavored water (placebo) during the experiment. Blood samples were collected during exercise and recovery, and muscle biopsies were taken from both legs before, after, and 90 and 180 min following exercise. Ingestion of BCAA doubled their concentration in both plasma and muscle while causing a 30%-40% reduction (P < 0.05 vs. placebo) in levels of aromatic amino acids in both resting and exercising muscle during 3-h recovery period. The muscle concentration of kynurenine decreased by 25% (P < 0.05) during recovery, similar in both resting and exercising leg and with both supplements, although plasma concentration of kynurenine during recovery was 10% lower (P < 0.05) when BCAA were ingested. Ingestion of BCAA reduced the plasma concentration of kynurenic acid by 60% (P < 0.01) during exercise and recovery, whereas the level remained unchanged with placebo. Exercise induced a three- to fourfold increase (P < 0.05) in muscle content of PGC-1α1 mRNA after 90 min of recovery under both conditions, whereas levels of KAT4 mRNA and protein were unaffected by exercise or supplement. In conclusion, the reduction of plasma levels of kynurenine and kynurenic acid caused by BCAA were not associated with any changes in the level of muscle kynurenine, suggesting that kynurenine metabolism was altered in tissues other than muscle.

Excess branched-chain amino acids alter myotube metabolism and substrate preference which is worsened by concurrent insulin resistance.

Branched-chain amino acids (BCAA) have been shown to enhance several cellular signaling pathways including protein synthesis and mitochondrial biogenesis, yet population data demonstrate a correlation between circulating BCAA and severity of insulin resistance which has been hypothesized to be, in part, a byproduct of BCAA inhibition of mitochondrial function. The purpose of this study is to examine the effect of a BCAA mixture on muscle metabolism and related gene expression in vitro. C2C12 myotubes were treated with a BCAA mixture containing leucine:isoleucine:valine at a ratio of 2:1:1 at 0.2, 2, or 20 mM (based on leucine content) for 6 days. qRT-PCR was used to measure metabolic gene expression. Oxygen consumption and extracellular acidification were used to assess mitochondrial and glycolytic metabolism, respectively. Mitochondrial content was determined via mitochondrial-specific staining. Despite significantly elevated mitochondrial staining, 6-day BCAA treatment reduced basal mitochondrial metabolism at a supraphysiological concentration (20 mM) in both insulin sensitive and resistant cells. Peak mitochondrial capacity was also reduced in insulin-resistant (but not insulin sensitive) cells. Conversely, basal glycolytic metabolism was elevated following 20 mM BCAA treatment, regardless of insulin resistance. In addition, insulin-resistant cells treated with 20 mM BCAA exhibited reduced gene expression of Ppargc1a, Cytc, Atp5b, Glut4, and several glycolytic enzymes versus insulin sensitive cells treated with 20 mM BCAA. Collectively, these findings suggest BCAA at supraphysiologically high levels may negatively alter mitochondrial metabolism, and concurrent insulin resistance may also diminish peak mitochondrial capacity, as well as impede molecular adaptations that support a transition to a glycolytic preference/compensation.

Branched-chain amino acids at supraphysiological but not physiological levels reduce myotube insulin sensitivity.

Branched-chain amino acids (BCAA) are often emphasized in the diets of avid exercisers, yet population data demonstrates a correlation between circulating BCAA and insulin resistance. However, it is unclear if BCAA independently promote insulin resistance in otherwise healthy cells. The purpose of this study is to examine the effect of a BCAA mixture on muscle insulin signaling in vitro in both insulin resistant and sensitive cells. C2C12 myotubes were treated with a BCAA mixture containing leucine:isoleucine:valine at a ratio of 2:1:1 at 0.2, 2, or 20mM (based on leucine content) for either 30min, 1day, or 6days. Western blot was used to assess insulin sensitivity of cells treated with BCAA both with and without concurrent insulin resistance, and, with and without insulin stimulation. BCAA treatment for 1day significantly reduced basal, but not insulin-stimulated pAkt expression. BCAA treatment for 6days resulted in significantly reduced basal insulin signaling in healthy cells and insulin-stimulated insulin signaling in insulin resistant (but not insulin sensitive) cells. Similar to previous observations demonstrating BCAA may correlate with insulin resistance during metabolically stressed conditions, we demonstrate excessively high BCAA exposure can negatively influence basal insulin signaling, as well as insulin sensitivity in insulin resistant myotubes. However, given the intentionally high concentrations of BCAA used in this study, the extent to which these observations translate to in vivo models is unclear and warrants further investigation.

Ketoanalogue supplements reduce mortality in patients with pre-dialysis advanced diabetic kidney disease: A nationwide population-based study

Metabolism dysregulation and protein energy wasting occur in patients with chronic kidney disease (CKD) and are associated with poor survival, especially in patients prior to starting dialysis. Accumulating evidence indicates that dietary supplementation with ketoanalogues (KAs, a mixture of branched-chain amino acids) exerts a variety of beneficial effects for patients with CKD. However, the role of KAs in diabetic kidney disease (DKD), one of the major causes of CKD, is still controversial. The aim of this study was to explore the impact of KA supplements on survival in patients with stage 5 DKD who have not yet started dialysis (DKD-5-ND). We analyzed a nationwide cohort retrieved from the National Health Insurance Research Database in Taiwan to study the long-term impact of KA supplements in patients with DKD-5-ND. We enrolled 15,782 incident pre-dialysis DKD patients between January 1, 2004 and December 31, 2007. Landmark analysis was used to eliminate immortal bias, and overlap weighting was used to balance differences between the KA users and nonusers in the beginning. The primary study endpoint was all-cause mortality, and the occurrence of permanent dialysis (presenting the end-stage renal disease, ESRD) and major adverse cardiovascular events (MACEs) was also evaluated. All patients were followed for five years or until death. The prevalence of KA usage in the DKD-5-ND patients was 6.3%. The 5-year all-cause mortality rate in the KA users was lower than that in the nonusers (34.7% vs 42.7%). After adjusting for known covariates, the KA users still had a lower risk of mortality (adjusted hazard ratio [aHR]: 0.73, 95% confidence interval [CI]: 0.66-0.82). In addition, the incidence of ESRD was also slightly lower among the KA users (90.9% for users vs 91.2% for nonusers, adjusted cause-specific hazard ratio [aCSHR]: 0.65, 95% CI: 0.61-0.69), and the occurrence of MACEs was lower (adjusted incidence rate ratios [aIRR]: 0.76, 95% CI: 0.67-0.86). Although the all-cause mortality was higher among patientsolder than 70 years (60.5% for KA users vs 46.5% for nonusers) the risk reduction seemed prominent among older patients (aHR: 0.65, 95% CI: 0.56-0.76 for patients aged ≥70 years; aHR: 0.82, 95% CI: 0.71-0.96 for patients aged<70 years). The reduction in risks of mortality was consistent in subgroup analysis and sensitivity tests. The use of KA supplements seemed to be beneficial for patients with DKD-5-ND; further in-depth analysis of using KA for these patients is warranted.

Determining Ideal Balance Among Branched-Chain Amino Acids (BCAA) as a Proof of Concept Study in Healthy Children

Abstract Objectives Medical foods for children with in-born errors of metabolism (propionic academia, PROP) are formulated with imbalanced mixture of the BCAA (high leucine, to minimal or no valine and isoleucine), and therefore their use is controversial. The objective of the current study was to determine an ideal BCAA ratio at which total body protein synthesis is optimized in healthy children using the indicator amino acid oxidation (IAAO) method. Methods The study design was based on the oxidation of the stable isotope L-[1–,13C] phenylalanine to ,13CO2 to compare protein synthesis among seven different BCAA ratios. Leucine intake was gradually reduced from current high doses in medical foods; isoleucine and valine were kept constant. This study was done as a proof of concept in healthy children, to allow characterization of the metabolic responses to wide range of leucine test intakes, to help design narrow BCAA ratio range to test in children with PROP. Results A total of 8 healthy children were studied, completing 42 study days. ANOVA showed significant differences in F13CO2 with different BCAA ratios; P value &amp;lt;0.001. A BCAA ratio of (leucine: Isoleucine: Valine = 1:0:0) was associated with the highest F13CO2 compared to other ratios (p value &amp;lt;0.001), indicating low total body protein synthesis. By reducing leucine intake, with BCAA ratio between (1: 0.26: 0.28 to 1:0.35:0.4) protein synthesis was optimized. Conclusions Using the IAAO method in healthy children, we tested for the first time the effect of different BCAA ratios on protein synthesis. Results from this study confirmed that the BCAA ratio of (leucine: Isoleucine: Valine = 1:0:0), which is similar to the ratio in medical foods, limited total body protein synthesis. Furthermore, a balanced BCAA ratio that optimized protein synthesis was found to be between (1: 0.26: 0.28) and (1: 0.35:0.4). Thus, we propose reformulating the BCAA mixture in medical foods, by reducing leucine content by 50%. Future research in children with PROP with our proposed BCAA ratio is necessary to confirm improved patient growth outcomes. Funding Sources Faculty of Applied Medical Sciences, Department of Clinical Nutrition, King Abdulaziz University and BC Children's Hospital Research Institute.

Branched-Chain Amino Acids and Seizures: A Systematic Review of the Literature.

Up to 40% of patients with epilepsy experience seizures despite treatment with antiepileptic drugs; however, branched-chain amino acid (BCAA) supplementation has shown promise in treating refractory epilepsy. The purpose of this systematic review was to evaluate all published studies that investigated the effects of BCAAs on seizures, emphasizing therapeutic efficacy and possible underlying mechanisms. On 31 January, 2017, the following databases were searched for relevant studies: MEDLINE (OvidSP), EMBASE (OvidSP), Scopus (Elsevier), the Cochrane Library, and the unindexed material in PubMed (National Library of Medicine/National Institutes of Health). The searches were repeated in all databases on 18 February, 2019. We only included full-length preclinical and clinical studies that were published in the English language that examined the effects of BCAA administration on seizures. Eleven of 2045 studies met our inclusion criteria: ten studies were conducted in animal models and one study in human subjects. Seven seizure models were investigated: the strychnine (one study), pentylenetetrazole (two studies), flurothyl (one study), picrotoxin (two studies), genetic absence epilepsy in rats (one study), kainic acid (two studies), and methionine sulfoximine (one study) paradigms. Three studies investigated the effect of a BCAA mixture whereas the other studies explored the effects of individual BCAAs on seizures. In most animal models and in humans, BCAAs had potent anti-seizure effects. However, in the methionine sulfoximine model, long-term BCAA supplementation worsened seizure propagation and caused neuron loss, and in the genetic absence epilepsy in rats model, BCAAs exhibited pro-seizure effects. The contradictory effects of BCAAs on seizure activity likely reflect differences in the complex mechanisms that underlie seizure disorders. Some of these mechanisms are likely mediated by BCAA's effects on glucose, glutamate, glutamine, and ammonia metabolism, activation of the mechanistic target of rapamycin signaling pathway, and their effects on aromatic amino acid transport and neurotransmitter synthesis. We propose that a better understanding of mechanisms by which BCAAs affect seizures and neuronal viability is needed to advance the field of BCAA supplementation in epilepsy.

BRANCHED CHAIN AMINO ACIDS AND THEIR IMPORTANCE IN NUTRITION

Branched chain amino acids (BCAA) - leucine, isoleucine and valine are essential amino acids which are metabolized directly in muscles and offer energy fuel to performance of the work. There is lot of evidences supporting the positive effect of BCAA supplementation on muscle growth. The main importance is attached particularly to leucine. There was observed that leucine supplementation increased protein synthesis in skeletal muscles after resistance exercise in young people and in elderly people suffered by sarcopenia as well. There is not exactly clear, what is the reason for the positive effect of BCAA to increase protein synthesis in muscles. Besides the positive effect of BCAA on muscle growth, there was observed their positive effect against fatigue and on a production of endogenous glucose, which is necessary to maintain the glucose balance in body during adaptation to stress. The minimum and maximum dose of BCAA is not established, but the daily recommended amount of leucine : isoleucine : valine is in a ratio 40:20:20 mg.kg body weight -1. It is recommended to use the mixture of BCAA rather than leucine individual, because of depletion other BCAA in body. There was observed no toxicity of BCAA even at high doses. The present review describes the metabolism of action and effect of BCAA on protein synthesis and physiological functions in human.

Effects of dietary branched-chain amino acid supplementation on growth and skeletal muscle cellularity in Japanese amberjack Seriola quinqueradiata

The present study investigated a determination method for skeletal muscle fiber diameters in Japanese amberjack Seriola quinqueradiata. We also investigated the effects of two supplements, a mixture of branched-chain amino acids (BCAAs) and valine alone, on body growth and skeletal muscle cellularity. The minor distances between two points on randomly selected individual fibers were measured and termed fiber diameters. Using growing fish (ranging from 4.8 g to 194.0 g in body weight), body weights and median fiber diameters were significantly correlated. A BCAA-supplemented diet (valine:leucine:isoleucine, 1:2:1) significantly increased the body weight after 105 days. The distribution frequency of fiber diameters between 61 and 81 μm was significantly higher in the 1 % BCAA group (P < 0.05) than in the control. However, dietary valine supplementation (1 %) had no effect on growth or skeletal muscle cellularity. These results indicated that hypertrophic growth occurred in the skeletal muscle of Japanese amberjack and was affected by dietary supplementation with a BCAA mixture.

The effect of a late-evening protein-containing snack on nitrogen balance in cirrhotic patients

PurposeThe aim of the study was to evaluate the effect of a late-evening protein-containing snack on nitrogen balance in cirrhotic patients.Patients and methodsThirty cirrhotic patients were divided into the following groups: group I, comprising 15 patients who received a late-evening 300-cal, 15-g protein-containing snack daily for 15 days; and group II, comprising 15 patients who received a late-evening supplement of amino acids (branched and essential) containing 22-g protein daily for 15 days. All patients were subjected to full history taking, clinical examination, and pelviabdominal ultrasound. Liver function tests, complete blood picture analysis, and estimation of blood urea and serum creatinine, urinary nitrogen loss, urea concentration in both serum and urine, and nitrogen balance were performed for all patients.ResultsThere was a significant increase in the mean level of serum albumin and red blood cell counts. The mean nitrogen balance significantly increased in both groups but more in patients who received branched chain amino acid (BCAA) supplementation. The mean serum ammonia significantly decreased in group II patients who received a late-evening BCAA supplementation, but not in patients of group I who received a late-evening protein-containing snack. There was no statistically significant difference in the levels of serum bilirubin or fasting blood glucose in either group.ConclusionThe results of the present study suggest that late-evening snacking with either a small protein-containing meal or a BCAA supplement improves the level of alanine transaminase, aspartate aminotransferase, serum albumin, nitrogen balance, ammonia, urea, and the general condition of the patient. The patients receiving BCAAs respond better than the snack group. A BCAA mixture as a late-evening snack is a favorable nutritional intervention for liver cirrhosis patients to repair hypercatabolism and sarcopenia and improve their nutritional status, such as nitrogen balance and serum albumin. These results need to be further confirmed in a larger number of patients and for a longer period of time.

Distinct effects of leucine or a mixture of the branched-chain amino acids (leucine, isoleucine, and valine) supplementation on resistance to fatigue, and muscle and liver-glycogen degradation, in trained rats

ObjectiveThe aim of this study was to evaluate the effects of the mixture of branched-chain amino acids (BCAAs) supplementation compared with leucine administered orally on muscle biochemical parameters of trained rats submitted to an exercise-induced protocol of glycogen depletion. MethodsAfter 6 wk of swimming exercise, 8 wk-old (250 g, adult) male Wistar rats were randomly divided into three experimental groups (n = 8 per group): the mixture of BCAAs (BCAAs), leucine (LEU), and placebo (PLA). All groups were submitted to swimming exercise for 6 wk and supplemented with either the mixture of BCAAs, leucine, or placebo during the last week of training. At week 7 of the protocol, the rats were submitted to an intermittent, progressive swimming test until exhaustion and sacrificed. Muscle gastrocnemius and liver were depicted to determine total glycogen, tricarboxylic acid cycle (TCA) intermediates, and enzymatic activities. Statistical evaluation was performed by one-way analysis of variance with Tukey post hoc test. ResultsBoth muscle and liver glycogen degradation ratio were significantly higher in the mixture of BCAAs group compared to the PLA group (P < 0.05) and the LEU group presented decreased liver glycogen degradation ratio compared with the mixture of BCAAs group (P < 0.05). Both muscle and liver glycogen content were significantly spared in the mixture of BCAAs and LEU groups compared to the PLA group (P < 0.01). A performance test demonstrated that LEU supplementation enhanced resistance to exhaustion compared to the mixture of BCAAs (P < 0.001), however, no difference was found when LEU supplementation was compared to PLA (P > 0.05) Muscle citrate content was significantly higher in the mixture of BCAAs group compared with the PLA group (P < 0.001). Muscle malate content was significantly elevated in the mixture of BCAAs group compared with both the PLA (P < 0.001) and LEU groups (P < 0.001). BCAT activity was significantly reduced in the mixture of BCAAs supplementation group compared with the LEU group (P < 0.001). ConclusionLeucine supplementation improved performance compared with the mixture of BCAAs supplementation, sparing muscle glycogen stores despite the augmentation of some TCA intermediate concentrations on the left side of the TCA cycle.

Appropriate amino acid mixtures for tryptophan depletion and tyrosine/phenylalanine depletion and the safety of long-term amino acid depletion in humans

AbbreviationsATD Acute tryptophan depletionAPTD Acute tyrosine/phenylalanine depletionGMP GlycomacropeptideTrp TryptophanTyr TyrosinePhe PhenylalanineDOPA dihydroxyphenylalanineDear Editor,In a recent review in this journal, Badawy ( 2013) discussedthe appropriate composition of amino acid mixtures for acutetryptophan depletion (ATD) and acute phenylalanine/tyrosinedepletion(APTD)studiesandsuggestedthatglycomacropeptide(GMP), which contains no aromatic amino acids, may be asuitable protein to use in acute depletion studies and long-termATD and APTD treatments of patients with mania and schizo-phrenia. The review raises a number of interesting issues but hasaspects that are problematic.1. The review suggests that GMP may be an effective nutri-tionaltherapyformanicand psychoticdisorders.Howev-er,thereviewdoesnotraisetheissueofwhetheraproteinwill necessarily be free of adverse effects. GMP lacksaromatic amino acids and, if given chronically, wouldcause the intake of amino acids to be imbalanced. Aspointed out by Young (2008), the extensive animal liter-ature on the effects of imbalanced amino acid diets indi-cates adverse effects including reductions in food intake,growth retardation, and the development of fatty liver.Furthermore, tyrosine (Tyr) and tryptophan (Trp) areessentialaminoacids,anddepletingthemmayhavesubtleeffectsonproteinsynthesis.Thepossibleimplicationsforbrain function of long-term mild disturbances of proteinsynthesisarenotknown.Rulingoutanyadverseeffectsoflong-term ATD or APTD in humans would be difficult,andanylong-termdepletionstudyinhumans,usingeitheramino acid mixtures or a protein such as GMP, would behard to justify ethically.2. The review mentions that GMP is lacking in histidine.This means that GMP would be expected to depletehistidine levels, but the implications of this are not men-tioned. In rats, histidine levels influence brain histaminelevels more than Trp levels influence brain serotoninlevels, and acute histidine depletion in humans, using ahistidine-deficient amino acid mixture, has behavioral ef-fects (van Ruitenbeek et al. 2009). Therefore, if GMP isused for acute ATD or APTD studies, histidine should beaddedtotheGMPinbothdepletionandcontrolconditionsto avoid a study on the combined effects of low histamineand low serotonin or low histamine and low dopamine.3. The review suggests that GMP may be useful for treatingmania by depleting dopamine. This is based on the studyof Scarna et al. (2003) who found a therapeutic effect,relativeto placebo, of giving a mixture of branchedchainamino acids (BCAA) to manic patients everyday for7 days. The effect was attributed to lowered dopamine,as the BCAA will inhibit the uptake of phenylalanine(Phe) and Tyr into the brain. However, the BCAA willalso inhibit the uptake of Trp into the brain. Two studiessuggest that depletion of Trp may have played a moreimportant role than depletion of Phe and Tyr in the ther-apeutic effect of the BCAA. Firstly, the Tyr hydroxylaseinhibitor α-methylparatyrosine had no consistent effecton the symptoms of manic patients (Bunney et al. 1971).Secondly,ATDimprovedthesymptomsofmanicpatientsmore than treatment with a placebo (Applebaum et al.2007). Therefore, if GMP has an effect on manic

Effects of Branched-Chain Amino Acid Supplementation on Plasma Concentrations of Free Amino Acids, Insulin, and Energy Substrates in Young Men

The present study was conducted to examine alterations in the concentrations of plasma free amino acids, glucose, insulin, free fatty acids (FFAs), and urea nitrogen induced by branched-chain amino acid (BCAA) supplementation in young men. Overnight-fasted subjects ingested drinks containing 1 or 5 g of a BCAA mixture (weight ratio of 1 : 2.3 : 1.2 for isoleucine : leucine : valine), and blood was intermittently collected for 3 h after ingestion. Ingestion of the BCAA mixture resulted in significant increases in the plasma concentrations of individual BCAAs, corresponding to the amounts of amino acids ingested. On the other hand, plasma concentrations of methionine and aromatic amino acids tended to decrease in the trial with 5 g BCAAs, suggesting that BCAA ingestion affects the metabolism of these amino acids. The ingestion of BCAAs temporarily increased plasma insulin levels and affected plasma concentrations of FFAs, but had almost no effect on glucose or urea nitrogen.

Influence of supplementation with branched-chain amino acids in combination with resistance exercise on p70S6 kinase phosphorylation in resting and exercising human skeletal muscle

Skeletal muscle growth is thought to be regulated by the mammalian target of rapamycin (mTOR) pathway, which can be activated by resistance exercise and branched-chain amino acids (BCAA). The major aim of the present study was to distinguish between the influence of resistance exercise and BCAA on key enzymes considered to be involved in the regulation of protein synthesis, including p70(S6) kinase (p70(S6k)). Nine healthy subjects (four men and five women) performed unilateral resistance exercise on two occasions separated by 1 month. Subjects were randomly supplied either a mixture of BCAA or flavoured water. Muscle biopsies were taken from both resting and exercising muscle before, after and 1 h after exercise. Phosphorylation of Akt was unaltered by either resistance exercise and/or BCAA supplementation whereas mTOR phosphorylation was enhanced (P<0.05) to a similar extent in both exercising and resting muscle following exercise in the absence (70-90%) and presence of BCAA supplementation (80-130%). Phosphorylation of p70(S6k) was unaffected by resistance exercise alone; however, BCAA intake increased (P<0.05) this phosphorylation in both legs following exercise. In resting muscle, a 5- and 16-fold increase in p70(S6k) was observed immediately after and 1 h after exercise, respectively, as compared to 11- and 30-fold increases in the exercising muscle. Phosphorylation of eukaryotic elongation factor 2 was attenuated 1 h after exercise (P<0.05) in both resting (10-40%) and exercising muscle (30-50%) under both conditions. The present findings indicate that resistance exercise and BCAA exert both separate and combined effects on the p70(S6k) phosphorylation in an Akt-independent manner.

Branched-chain Amino Acids and Alleviation of Muscle Damage and Fatigue in the Hyper-running Rat Model

Oral administration of a mixture of amino acids during exercise reduced muscle damage and abolished post-exercise fatigue in the hyper-running rat model utilizing the stimulation of the ventromedial nucleus of the hypothalamus (VMH) (Okada et al., 2006 ACSM abstract). However, it has been suggested that branched-chain amino acids (BCAA) alone exert beneficial effects against exercise-induced muscle damage. PURPOSE: To determine effects and an optimum dose of BCAA alone on muscle damage and fatigue in hyper-running rat. METHODS: The BCAA mixture was given at doses of 0 (control), 0.5, 1.0,2.0, and 4.0 g/kg BW in a 0.5 % of carboxymethylcellulose solution. The BCAA mixture was composed of leucine, isoleucine, and valine at the ratio of 2: 1: 1 by weight. Hyper-running was induced by microinjection of bicuculine into the VMH via an implanted stainless steel guide cannula. Blood samples were collected at pre-running, immediately after the running, and up to 48 hours thereafter to determine creatine phosphokinase (CPK) activity and concentrations of lactic acid, ammonia, urea, and free amino acids. Food intake was measured before and after the running. RESULTS: The distance of running was not different among all groups. After the running, the CPK activity was elevated in all groups, having the highest CPK activity in the control and less than half as much in 0.5, 1.0, and 4.0 g/kg groups. In the control, the elevated CPK activity did not return to the basal level in 6 hours. At 2-hour post-running, CPK activities in 0.5, 1.0, and 4.0 g/kg groups were significantly lower than in the control. Blood lactic acid rose in all groups after the running, however, the rise was significantly less in 0.5, 1.0, and 4.0 g/kg groups than in the control. Plasma ammonia was increased in the control and the 4.0 g/kg groups 2 hours after the running. Plasma urea was elevated in 2.0 and 4.0 g/kg group than in other groups 6 hours after the running. Food intake was significantly reduced by 20 % in all but the 1.0 g/kg group after the running. CONCLUSIONS: Oral administration of the BCAA mixture alleviated muscle damage and blocked the onset of fatigue resulting from hyper-running at the optimum dose of 1.0 g/kg BW.

BCAA-enriched snack improves nutritional state of cirrhosis

Objective A late evening snack improves the catabolic state in patients with advanced liver cirrhosis. We tested whether long-term (3 mo) late evening snacking that included a branched-chain amino acid (BCAA)–enriched nutrient mixture produces a better nutritional state and better quality of life than ordinary food in patients with hepatitis C virus–positive liver cirrhosis. Methods In a multicenter, randomized study, 48 patients with liver cirrhosis received late-evening supplementation with the BCAA-enriched nutrient mixture or ordinary food, such as a rice ball or bread, for 3 mo. During the study period, each patient was instructed on energy and protein intake. Blood biochemical data, nitrogen balance, respiratory quotient, and health-related quality of life (Short Form 36 questionnaire) were evaluated at baseline and at the end of the study. Results Total and late-evening energy intakes were similar in the two groups at 3 mo. Serum albumin level, nitrogen balance, and respiratory quotient were significantly improved by the BCAA mixture but not by ordinary food. The parameters of the Short Form 36 did not statistically significantly improve over 3 mo in either group. Conclusion Long-term oral supplementation with a BCAA mixture is better than ordinary food in a late evening snack at improving the serum albumin level and the energy metabolism in patients with cirrhosis.

Emotion-based decision-making in healthy subjects: short-term effects of reducing dopamine levels.

Converging evidences from animal and human studies suggest that addiction is associated with dopaminergic dysfunction in brain reward circuits. So far, it is unclear what aspects of addictive behaviors are related to a dopaminergic dysfunction. We hypothesize that a decrease in dopaminergic activity impairs emotion-based decision-making. To demonstrate this hypothesis, we investigated the effects of a decrease in dopaminergic activity on the performance of an emotion-based decision-making task, the Iowa gambling task (IGT), in 11 healthy human subjects. We used a double-blind, placebo-controlled, within-subject design to examine the effect of a mixture containing the branched-chain amino acids (BCAA) valine, isoleucine and leucine on prolactin, IGT performance, perceptual competency and visual aspects of visuospatial working memory, visual attention and working memory, and verbal memory. The expectancy-valence model was used to determine the relative contributions of distinct IGT components (attention to past outcomes, relative weight of wins and losses, and choice strategies) in the decision-making process. Compared to placebo, the BCAA mixture increased prolactin levels and impaired IGT performance. BCAA administration interfered with a particular component process of decision-making related to attention to more recent events as compared to more distant events. There were no differences between placebo and BCAA conditions for other aspects of cognition. Our results suggest a direct link between a reduced dopaminergic activity and poor emotion-based decision-making characterized by shortsightedness, and thus difficulties resisting short-term reward, despite long-term negative consequences. These findings have implications for behavioral and pharmacological interventions targeting impaired emotion-based decision-making in addictive disorders.

The Effect of Supplementation with Branched-Chain Amino Acids on Cognitive Function in Active Dogs

A previous study has shown that human athletes given branched-chain amino acids (BCAA) in the form of a drink before and during exercise performed better on complex cognitive tests following exercise (1). The athletes were given a mixture of BCAA (40% valine, 35% leucine, and 25% isoleucine) in a 7% carbohydrate solution. The total amount of BCAA supplied to the subjects was 5.3 g. The athletes were taking part in a 30-km cross-country race and were asked to perform a variety of cognitive tasks and also to give blood samples before and after the race. The blood samples were necessary for measuring plasma free-tryptophan and plasma glucose concentrations. It is suggested that exercise increases the plasma concentration of tryptophan, which competes with BCAA for a common transport mechanism for entry to the brain. This increased concentration ratio would be expected to lead to an increased rate of transport of tryptophan into the brain, increased brain concentration, and hence increased serotonin (5-hydroxytrptamine, 5-HT). Studies with rats have shown that an increase in the concentration of 5-HT in the brain is associated with sleep as well as reduced levels of aggression (2). If BCAA can provide cognitive improvement in active dogs, then there could be numerous potential benefits for the dog and owner. The particular types of dogs that might benefit are: assistance, show, agility, working, and obedience dogs. Potentially, BCAA could be added in appropriate amounts to commercial diets, but more impact could be achieved if BCAA were provided in a snack or treat that the dog could eat just before an extra boost of energy and cognitive performance is required; similar to the way energy bars are used by humans.

Exercise-Dependent Preference for a Mixture of Branched-Chain Amino Acids and Homeostatic Control of Brain Serotonin in Exercising Rats

In this article we discuss studies showing that rats are able to regulate their intake of BCAA depending on the level of exercise, and that they will choose a solution of BCAA over water during times of intense exercise. We found that the voluntary intake of a solution made of BCAA, L-arginine and L-glutamine positively correlated with the timing and volume of exercise during the dark (active) period of the circadian rhythm. In the second behavioral protocol in which rats were fed BCAA fortified diet (2.0%, wt:wt), we observed voluntarily increased volume of physical activity beginning from d 4 of feeding on. In the second, neuro-behavioral, part of the study we measured the brain content of 5-hydroxytryptamine (5-HT) as well as plasma amino acid profiles in well-trained exercising rats to test a hypothesis that BCAA may alleviate central aspects of fatigue. A solution made of BCAA, L-arginine, and L-glutamine applied before running elevated the BCAA/tryptophan plasma ratio at the end of and after running, and decreased 5-HT release in the lateral hypothalamus and amygdala after running, when compared with the controls. The exercise-related shift in the fluid preference toward a BCAA-based solution suggests an ergogenic benefit. The forced-running study shows the lateral hypothalamus and possibly amygdala might be the critical brain regions implied in the central effects of a BCAA-based solution.

Oral administration of branched-chain amino acids activates the mTOR signal in cirrhotic rat liver

BCAA granules (a mixture of branched-chain amino acids) have been used to reverse the hypoalbuminemia of decompensated liver cirrhotic patients in Japan. Our previous studies showed that BCAA promoted albumin secretion through the mTOR signal transduction pathway in rat primary hepatocyte culture [Ijichi C, Matsumura T, Tsuji T, Eto Y. Branched-chain amino acids promote albumin synthesis in rat primary hepatocytes through the mTOR signal transduction system. Biochem Biophys Res Commun 2003;303:59-64]. However, the mTOR-activating effect of BCAA in the experimental cirrhotic animals presenting with hypoalbuminemia has not yet been examined. The purpose of this study is to assess whether oral administration of BCAA induces mTOR activity in the livers of normal rats and CCl(4)-induced cirrhotic rats (CCl(4) rats). Biochemical analysis of liver extracts isolated from several rats showed that oral administration of BCAA (0.75g/kg body weight (BW)) induced phosphorylation of 4E-BP1 and stimulated the enzymatic activity of p70 S6K. Both of these molecules act downstream of mTOR. From the results, we conclude that orally administrated BCAA augments albumin synthesis in the liver, not only by supplementation of material substrates for protein synthesis, but also by induction of an mTOR signal that is critical for translational initiation. Furthermore, we conclude that induction of mTOR signaling is one of the major pharmacological mechanisms by which BCAA granules reverse the hypoalbuminemia of cirrhotic patients.