Branched-chain amino acid levels are inversely associated with incident and prevalent chronic kidney disease in people with type 2 diabetes

AIM

To investigate the association of plasma metabolites with incident and prevalent chronic kidney disease (CKD) in people with type 2 diabetes and establish whether this association is causal.

MATERIALS AND METHODS

The Hoorn Diabetes Care System cohort is a large prospective cohort consisting of individuals with type 2 diabetes from the northwest part of the Netherlands. In this cohort we assessed the association of baseline plasma levels of 172 metabolites with incident (Ntotal = 462/Ncase = 81) and prevalent (Ntotal = 1247/Ncase = 120) CKD using logistic regression. Additionally, replication in the UK Biobank, body mass index (BMI) mediation and causality of the association with Mendelian randomization was performed.

RESULTS

Elevated levels of total and individual branched-chain amino acids (BCAAs)-valine, leucine and isoleucine-were associated with an increased risk of incident CKD, but with reduced odds of prevalent CKD, where BMI was identified as an effect modifier. The observed inverse effects were replicated in the UK Biobank. Mendelian randomization analysis did not provide evidence for a causal relationship between BCAAs and prevalent CKD.

CONCLUSIONS

Our study shows the intricate relationship between plasma BCAA levels and CKD in individuals with type 2 diabetes. While an association exists, its manifestation varies based on disease status and BMI, with no definitive evidence supporting a causal link between BCAAs and prevalent CKD.

Effects of serum branched-chain amino acids on nonalcoholic fatty liver disease and subsequent cardiovascular disease

BACKGROUND

To reveal the role of branched-chain amino acids (BCAAs) in the development and progression of nonalcoholic fatty liver disease (NAFLD) and the effect on the incidence of subsequent cardiovascular disease.

METHODS

A total of 1302 subjects in the cohort study of the Huai'an Diabetes Prevention Program were divided into two groups according to whether NAFLD was present at baseline. The group without NAFLD at baseline was only followed up, and the group with NAFLD at baseline received diet and exercise interventions. Anthropometric and biochemical examinations were performed at baseline and at the end of 4 years for all subjects. Serum BCAA (leucine, isoleucine, and valine) levels were measured by hydrophilic interaction chromatography-tandem mass spectrometry. The associations of baseline serum BCAA levels with the risk for NAFLD, coronary heart disease (CHD), and cardiovascular events (CVEs) after 4 years were further evaluated.

RESULTS

(1) At baseline and after the 4-year follow-up, baseline serum leucine, valine, and total BCAAs in the NAFLD group were significantly higher than those in the non-NAFLD group (p < 0.05). (2) According to whether NAFLD was present at baseline and after follow-up, all subjects were divided into four groups, including the control group, new case group, improvement group, and unchanged group. There was no significant difference in baseline BCAAs levels between the new case group and the improvement group (p > 0.05). (3) Risk factors for the occurrence and development of NAFLD were analysed by a multiple logistic regression model according to whether NAFLD existed at baseline. Serum leucine (OR = 1.058, 95% CI 1.005-1.114, p = 0.033) and total BCAAs (OR = 1.023, 95% CI 1.001-1.046, p = 0.045) were independent risk factors for new-onset NAFLD. Serum valine (OR = 1.131, 95% CI 1.043-1.226, p = 0.003), and total BCAAs (OR = 1.040, 95% CI 1.003-1.078, p = 0.035) were independent risk factors showing that NAFLD could not be reversed. (4) The cross-table Chi-square test showed that the incidence of both CHD and CVEs was significantly highest in the new case group (p < 0.05). (5) After adjusting for confounding factors, baseline isoleucine, valine, and BCAA levels were independently associated with new-onset CHD in subjects with or without NAFLD at baseline (p < 0.05).

CONCLUSIONS

High BCAA levels exacerbate the risk of CHD and CVEs by influencing the occurrence and progression of NAFLD. However, lifestyle interventions could reverse the risk of NAFLD, CHD and CVEs associated with BCAAs.

Anti-fibrotic effects of branched-chain amino acids on hepatic stellate cells

BACKGROUND/AIMS

Patients with liver cirrhosis (LC) have low levels of branched-chain amino acids (BCAAs). There is accumulating evidence that BCAAs have anti- fibrotic effects in cirrhosis. This study is aimed to evaluate the effect of BCAAs on the function and phenotype of activated hepatic stellate cells (HSCs).

METHODS

LX-2, an immortalized human stellate cell line, was used in in vitro experiments. LX-2 cells were exposed to transforming growth factor β1 (TGF-β1) and BCAAs or to valine, leucine, and isoleucine, which are components of BCAAs. Activation of the TGF-β signaling pathway in LX-2 cells was observed using real-time quantitative polymerase chain reaction and Western blotting.

RESULTS

The increased expression of snail family transcriptional repressor 1 (SNAI1) was observed in LX-2 cells activated by TGF-β1. After BCAA treatment, its expression was significantly decreased at the mRNA level. The increased expression of Col1α1 and TIMP2 at the mRNA level and alpha smooth muscle actin at the protein level in activated LX-2 cells decreased after BCAA treatment. Among the BCAA components, leucine and valine significantly abrogated TGF-β-induced activation of LX-2 cells. BCAA treatment led to the decreased phosphorylation of Smad2 and p38 proteins, which are markers for Smad and Smad-independent p38 mitogen-activated protein kinase signaling pathways, respectively.

CONCLUSION

BCAA treatment can improve hepatic fibrosis by directly affecting the activated state of hepatic stellate cells through inhibition of the TGF-β signaling pathway. Among BCAA components, leucine and valine mainly abrogated TGF-β-induced activation of HSCs. Our results suggest that BCAA may be used to attenuate the progression of liver fibrosis.

Small Intestinal Bacterial Overgrowth Diagnosed by a Breath Test and Improved by Rifaximin in a Patient with Hepatic Encephalopathy and Alcoholic Liver Cirrhosis

A 66-year-old Japanese man was admitted to our hospital with grade 2 hepatic encephalopathy (HE). Abdominal computed tomography and laboratory examinations revealed decompensated liver cirrhosis. Intravenous administration of branched-chain amino acids immediately ameliorated the HE, and lactulose was initiated. However, a breath test revealed small intestinal bacterial overgrowth (SIBO); therefore, rifaximin was additionally initiated. The breath test was repeated after discharge, when no evidence of SIBO or overt HE was identified. This case suggested that a breath test is effective for the identification of SIBO and that the administration of a poorly absorbed antibiotic should be considered in SIBO-positive HE patients taking lactulose.

Consumption of a Branched-Chain Amino Acid (BCAA) during Days 2-10 of Pregnancy Causes Abnormal Fetal and Placental Growth: Implications for BCAA Supplementation in Humans

A relatively large branched-chain amino acid (BCAA) supplement, consumed for more than 10 days, appears to be especially effective at alleviating muscle damage and soreness during intense human training. However, perturbations in amino acid and protein consumption could have unwanted transgenerational effects on male and female reproduction. This paper hypothesizes that isoleucine consumption by female mice from days 2 to 10 of pregnancy will alter fetal and placental growth later in gestation. Mice that had received 118 mM isoleucine in their drinking water delivered pups on day 19 of pregnancy that were 9% larger than normal, whereas the reverse was true for pups born on day 20. Moreover, the inverse correlation between birth weight and litter size was lost in mice that previously consumed excess isoleucine. Similarly, the normal correlations between fetal and placental weights were lost by day 18 of pregnancy in mice that had consumed excess isoleucine. Mice that consumed excess isoleucine had placentas smaller than, and fetuses larger than normal on day 18 of pregnancy, but the reverse was true on day 15. Other unintended and unexpected effects of BCAA consumption should be studied more thoroughly due to the increasing use of BCAAs to alleviate muscle damage and soreness in athletes.

Animal Protein Intake Is Associated with General Adiposity in Adolescents: The Teen Food and Development Study

Protein plays a crucial role in the growth and development of adolescents. However, being a secondary energy source, protein’s role in obesity has been sidelined. We examined whether intake of protein (total, animal, plant), branched-chain (BCAAs), and sulfur-containing (SCAAs) amino acids are associated with general body and central obesity and body composition in a cross-sectional study among healthy adolescents. Students aged 12–18 years old (n = 601) in schools near two major Adventist universities in California and Michigan provided dietary data via a validated web-based food frequency questionnaire (FFQ) and anthropometric data during school visits. Intakes of total, animal, and plant proteins, and BCAAs and SCAAs were derived from FFQ data. We defined general body obesity with body-mass-index-for-age (BMIz) z-scores and central obesity with waist-to-height ratios (WHtR). After full adjustment for covariates, multiple regression analyses showed significant positive associations between intakes of total protein (β = 0.101, 95% CI: 0.041, 0.161), animal protein (β = 0.118, 95% CI: 0.057, 0.178), BCAAs (β = 0.056, 95% CI: 0.025, 0.087), and SCAAs (β = 0.025, 95% CI: 0.012, 0.038) with general body adiposity. Animal protein (β = 0.017, 95% CI: 0.001, 0.033) and SCAAs (β = 0.004, 95% CI: 0.000, 0.008) were also associated with central obesity. Total and animal protein and BCAA and SCAA were also significantly associated with fat mass. Our findings suggest that high protein intake may pose a possible detriment to adolescent health. Longitudinal and safety evaluation studies are recommended.

Dietary Intake of Branched-Chain Amino Acids and Risk of Colorectal Cancer

Branched-chain amino acids (BCAA) are essential amino acids, and emerging evidence suggests that BCAAs may mediate pathways related to cancer progression, possibly due to their involvement in insulin metabolism. We investigated the association between dietary intake of BCAAs with colorectal cancer risk in three prospective cohorts: the Nurses' Health Study I [(NHS), number of participants (n) at baseline = 77,017], NHS II (n = 92,984), and the Health Professionals Follow-up Study [(HPFS) n = 47,255]. Validated food frequency questionnaires were administered every 4 years and follow-up questionnaires on lifestyle biennially. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression models. Pooled HRs were obtained using random effect models. After up to 28 years of follow-up, 1,660 cases were observed in NHS, 306 in NHS II, and 1,343 in HPFS. In multivariable adjusted models, we observed a weak inverse association between BCAA intake and colorectal cancer [highest vs. lowest quintile, pooled HR including all three cohorts (95% CI): 0.89 (0.80-1.00), P _trend = 0.06, HR per standard deviation (SD) increment 0.95 (0.92-0.99)]. However, after including dairy calcium to the models, BCAA intake was no longer associated with risk of colorectal cancer [HR 0.96 (0.85-1.08), P _trend = 0.50, HR per SD increment 0.97 (0.93-1.01)]. We did not find evidence that higher dietary BCAA intake is associated with higher risk of colorectal cancer. As this is the first prospective study to examine the association between BCAA intake and colorectal cancer, our findings warrant investigation in other cohorts.

Dietary Intakes of Branched Chain Amino Acids and the Incidence of Hypertension: A Population-Based Prospective Cohort Study

BACKGROUND

Dietary amino acids have been associated with blood pressure (BP) in previous studies; we conducted this study to examine the association between dietary branched chain amino acids (BCAAs) and the incidence of hypertension among participants of the Tehran Lipid and Glucose Study (TLGS).

METHODS

Analyses were conducted on 4,288 participants aged 20-70 years, who were free of hypertension at baseline (2008- 2011) and were followed for 3 years (2011-2014) to ascertain incident hypertension. Dietary intakes of BCAAs including, valine, leucine, and isoleucine were collected at baseline using the food frequency questionnaire (FFQ). Odds ratio (OR) of hypertension were determined by logistic regression across quartiles of BCAAs, adjusted for sex, age, smoking status, physical activity, body mass index (BMI), diabetes, and some dietary factors.

RESULTS

The mean ± standard deviation for age and BMI of participants (41.9% men) were 39.7 ± 12.8 years and 26.9 ± 4.6 kg/ m2 , respectively. The median intakes of total BCAAs, valine, leucine, and isoleucine was 17.9, 5.5, 7.8, and 4.5 percentage of total amino acids intake, respectively. We documented 429 (10%) hypertension incident cases. The multivariable adjusted OR for the highest vs lowest quartiles of BCAAs was 1.54 (95% confidence interval (CI):1.03-2.32; P for trend = 0.05); furthermore, the OR (95% CI) of hypertension for the highest vs the lowest quartile of valine was 1.61 (1.10-2.36; P for trend = 0.009) in the fully adjusted model. However, we found no significant association between leucine and isoleucine with incidence of hypertension.

CONCLUSION

Findings indicated that higher BCAA intake, in particular valine, is associated with higher risk of incident hypertension.

Long-Term Effects of Dietary Protein and Branched-Chain Amino Acids on Metabolism and Inflammation in Mice

Aging is the main factor involved in the onset of degenerative diseases. Dietary protein restriction has been shown to increase the lifespan of rodents and improve metabolic phenotype. Branched-chain amino acids (BCAA) can act as nutrient signals that increase the lifespan of mice after prolonged supplementation. It remains unclear whether the combination of protein restriction and BCAA supplementation improves metabolic and immunological profiles during aging. Here, we investigated how dietary protein levels and BCAA supplementation impact metabolism and immune profile during a 12-month intervention in adult male C57BL/6J mice. We found that protein restriction improved insulin tolerance and increased hepatic fibroblast growth factor 21 mRNA, circulating interleukin (IL)-5 concentration, and thermogenic uncoupling protein 1 in subcutaneous white fat. Surprisingly, BCAA supplementation conditionally increased body weight, lean mass, and fat mass, and deteriorated insulin intolerance during protein restriction, but not during protein sufficiency. BCAA also induced pro-inflammatory gene expression in visceral adipose tissue under both normal and low protein conditions. These results suggest that dietary protein levels and BCAA supplementation coordinate a complex regulation of metabolism and tissue inflammation during prolonged feeding.

Diabetes and branched-chain amino acids: What is the link?

Branched-chain amino acids (BCAA) have increasingly been studied as playing a role in diabetes, with the PubMed search string "diabetes" AND "branched chain amino acids" showing particular growth in studies of the topic over the past decade (Fig. ). In the Young Finn's Study, BCAA and, to a lesser extent, the aromatic amino acids phenylalanine and tyrosine were associated with insulin resistance (IR) in men but not in women, whereas the gluconeogenic amino acids alanine, glutamine, or glycine, and several other amino acids (i.e. histidine, arginine, and tryptophan) did not show an association with IR. Obesity may track more strongly than metabolic syndrome and diabetes with elevated BCAA. In a study of 1302 people aged 40-79; higher levels of BCAA tracked with older age, male sex, and metabolic syndrome, as well as with obesity, cardiovascular risk, dyslipidemia, hypertension, and uric acid. Medium- and long-chain acylcarnitines, by-products of mitochondrial catabolism of BCAAs, as well as branched-chain keto acids and the BCAA themselves distinguished obese people having versus not having features of IR, and in a study of 898 patients with essential hypertension, the BCAA and tyrosine and phenylalanine were associated with metabolic syndrome and impaired fasting glucose. In a meta-analysis of three genome-wide association studies, elevations in BCAA and, to a lesser extent, in alanine tracked with IR, whereas higher levels of glutamine and glycine were associated with lesser likelihood of IR. Given these associations with IR, it is not surprising that a number of studies have shown higher BCAA levels in people with and prior to development of type 2 diabetes (T2D), although this has particularly been shown in Caucasian and Asian ethnic groups while not appearing to occur in African Americans. Similarly, higher BCAA levels track with cardiovascular disease. [Figure: see text] The metabolism of BCAA involves two processes: (i) a reversible process catalysed by a branched-chain aminotransferase (BCAT), either cytosolic or mitochondrial, requiring pyridoxal to function as an amino group carrier, by which the BCAA with 2-ketoglutarate produce a branched-chain keto acid plus glutamate; and (ii) the irreversible mitochondrial process catalysed by branched-chain keto acid dehydrogenase (BCKDH) leading to formation of acetyl-coenzyme A (CoA), propionyl-CoA, and 2-methylbutyryl-CoA from leucine, valine, and isoleucine, respectively, which enter the tricarboxylic acid (Krebs) cycle as acetyl-CoA, propionyl-CoA, and 2-methylbutyryl-CoA, respectively, leading to ATP formation. The BCAA stimulate secretion of both insulin and glucagon and, when given orally, of both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), with oral administration leading to greater and more prolonged insulin and glucagon secretion. Insulin may particularly reduce BCAA turnover to a greater extent than that of other amino acids, and decreases the appearance and increases the uptake of amino acids. However, older studies of the effect of glucose or insulin on BCAA concentrations and rates of leucine appearance and oxidation showed no reduction in T2D, although the higher baseline levels of BCAA in obesity have long been recognized. Impaired function of BCAT and BCKDH has been posited, either as a primary genetic abnormality or due to effects of elevated fatty acids, proinflammatory cytokines, or insulin levels with consequent accumulation of branched-chain keto acids and metabolites such as diacylglycerol and ceramide, potentially contributing to the development of further insulin resistance, and decreased skeletal muscle BCAT and BCKDH expression has been shown in people with diabetes, supporting this concept. A Mendelian randomization study used measured variation in genes involved in BCAA metabolism to test the hypothesis of a causal effect of modifiable exposure on IR, showing that variants in protein phosphatase, Mg²⁺ /Mn²⁺ dependent 1K (PPM1K), a gene encoding the mitochondrial phosphatase activating the BCKDH complex, are associated with T2D, but another such study suggested that genetic variations associated with IR are causally related to higher BCAA levels. Another hypothesis involves the mammalian target of rapamycin complex 1 (mTORC1), which is activated by BCAA, as well as by insulin and glucose via cellular ATP availability. If this is the relevant pathway, BCAA overload may cause insulin resistance by activation of mammalian target of rapamycin (mTOR), as well as by leading to increases in acylcarnitines, with mTOR seen in this scenario as a central signal of cross-talk between the BCAA and insulin. At this point, whether whole-body or tissue-specific BCAA metabolism is increased or decreased in states of insulin-resistant obesity and T2D is uncertain. Insulin action in the hypothalamus induces but overfeeding decreases hepatic BCKDH, leading to the concept that hypothalamic insulin resistance impairs BCAA metabolism in obesity and diabetes, so that plasma BCAAs may be markers of hypothalamic insulin action rather than direct mediators of changes in IR. A way to address this may be to understand the effects of changes in diet and other interventions on BCAA, as well as on IR and T2D. In an animal model, lowering dietary BCAA increased energy expenditure and improved insulin sensitivity. Two large human population studies showed an association of estimated dietary BCAA intake with T2D risk, although another population study showed higher dietary BCAA to be associated with lower T2D risk. Ethnic differences, reflecting underlying differences in genetic variants, may be responsible for such differences. In the study of Asghari et al. in the current issue of the Journal of Diabetes, BCAA intake was associated with the development of subsequent IR. Studies of bariatric surgery suggest lower basal and post-insulin infusion BCAA levels are associated with greater insulin sensitivity, with reductions in BCAA not seen with weight loss per se with gastric band procedures, but occurring after Roux-en-Y gastric bypass, an intervention that may have metabolic benefits over and above those from reduction in body weight. The gut microbiota may be important for the supply of the BCAA to mammalian hosts, either by de novo biosynthesis or by modifying nutrient absorption. A final fascinating preliminary set of observations is that of the effects of empagliflozin on metabolomics; evidence of increased Krebs cycle activation and of higher levels of BCAA metabolites, such as acylcarnitines, suggests that sodium-glucose cotransporter 2 (SGLT2) inhibition may, to some extent, involve BCAA metabolism. Certainly, we do not yet have a full understanding of these complex associations. However, the suggestion of multiple roles of BCAA in the development of IR promises to be important and to lead to the development of novel effective T2D therapies.

High dietary intake of branched-chain amino acids is associated with an increased risk of insulin resistance in adults

BACKGROUND

The aim of this study was to investigate the association between branched-chain amino acid (BCAA) intake and markers of insulin metabolism in adults.

METHODS

This cohort study was conducted within the framework of the Tehran Lipid and Glucose Study on 1205 subjects, aged ≥20 years, who were followed-up for a mean of 2.3 years. Dietary intake of BCAAs, including valine, leucine, and isoleucine, was determined using a valid and reliable food frequency questionnaire. Hyperinsulinemia, β-cell dysfunction, insulin resistance (IR), and insulin insensitivity were determined according to optimal cut-off values. Logistic regression was to estimate the occurrence of IR across tertiles of BCAA intake.

RESULTS

The mean (± SD) age and BCAA intake of participants (43% male) at baseline were 42.7 ± 13.1 years and 13.8 ± 5.1 g/day, respectively. The incidence of hyperinsulinemia, β-cell dysfunction, insulin insensitivity, and IR was 19.5%, 24.0%, 28.0%, and 12.5%, respectively. After adjustment for confounding variables, subjects in the highest tertile for total BCAAs (odds ratio [OR] 1.67; 95% confidence interval [CI] 1.03-2.71), leucine (OR 1.75; 95% CI 1.09-2.82), and valine (OR 1.61; 95% CI 1.01-2.60) intake had a greater risk of incident IR than subjects in the lowest tertile. A higher intake of isoleucine was not associated with risk of incident IR. There was no association of total BCAAs, leucine, isoleucine, and valine intake with the risk of hyperinsulinemia, insulin insensitivity, or β-cell dysfunction.

CONCLUSION

The findings of this study support the hypothesis that higher intakes of BCAAs may have adverse effects on the development of IR.

Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review

Amino acids and more precisely, branched-chain amino acids (BCAAs), are usually consumed as nutritional supplements by many athletes and people involved in regular and moderate physical activities regardless of their practice level. BCAAs have been initially shown to increase muscle mass and have also been implicated in the limitation of structural and metabolic alterations associated with exercise damage. This systematic review provides a comprehensive analysis of the literature regarding the beneficial effects of BCAAs supplementation within the context of exercise-induced muscle damage or muscle injury. The potential benefit of a BCAAs supplementation was also analyzed according to the supplementation strategy-amount of BCAAs, frequency and duration of the supplementation-and the extent of muscle damage. The review protocol was registered prospectively with Prospective Register for Systematic Reviews (registration number CRD42017073006) and followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Literature search was performed from the date of commencement until August 2017 using four online databases (Medline, Cochrane library, Web of science and ScienceDirect). Original research articles: (i) written in English; (ii) describing experiments performed in Humans who received at least one oral BCAAs supplementation composed of leucine, isoleucine and valine mixture only as a nutritional strategy and (iii) reporting a follow-up of at least one day after exercise-induced muscle damage, were included in the systematic review analysis. Quality assessment was undertaken independently using the Quality Criteria Checklist for Primary Research. Changes in indirect markers of muscle damage were considered as primary outcome measures. Secondary outcome measures were the extent of change in indirect markers of muscle damage. In total, 11 studies were included in the analysis. A high heterogeneity was found regarding the different outcomes of these studies. The risk of bias was moderate considering the quality ratings were positive for six and neutral for three. Although a small number of studies were included, BCAAs supplementation can be efficacious on outcomes of exercise-induced muscle damage, as long as the extent of muscle damage was low-to-moderate, the supplementation strategy combined a high daily BCAAs intake (>200 mg kg^-1 day^-1) for a long period of time (>10 days); it was especially effective if taken prior to the damaging exercise.

Branched-chain amino acids for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a brain dysfunction with neurological and psychiatric changes associated with liver insufficiency or portal-systemic shunting. The severity ranges from minor symptoms to coma. A Cochrane systematic review including 11 randomised clinical trials on branched-chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy.

SEARCH METHODS

We identified trials through manual and electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded and Conference Proceedings Citation Index - Science, and LILACS (May 2017).

SELECTION CRITERIA

We included randomised clinical trials, irrespective of the bias control, language, or publication status.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data based on published reports and collected data from the primary investigators. We changed our primary outcomes in this update of the review to include mortality (all cause), hepatic encephalopathy (number of people without improved manifestations of hepatic encephalopathy), and adverse events. The analyses included random-effects and fixed-effect meta-analyses. We performed subgroup, sensitivity, regression, and trial sequential analyses to evaluate sources of heterogeneity (including intervention, and participant and trial characteristics), bias (using The Cochrane Hepato-Biliary Group method), small-study effects, and the robustness of the results after adjusting for sparse data and multiplicity. We graded the quality of the evidence using the GRADE approach.

MAIN RESULTS

We found 16 randomised clinical trials including 827 participants with hepatic encephalopathy classed as overt (12 trials) or minimal (four trials). Eight trials assessed oral BCAA supplements and seven trials assessed intravenous BCAA. The control groups received placebo/no intervention (two trials), diets (10 trials), lactulose (two trials), or neomycin (two trials). In 15 trials, all participants had cirrhosis. We classed seven trials as low risk of bias and nine trials as high risk of bias (mainly due to lack of blinding or for-profit funding). In a random-effects meta-analysis of mortality, we found no difference between BCAA and controls (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.69 to 1.11; 760 participants; 15 trials; moderate quality of evidence). We found no evidence of small-study effects. Sensitivity analyses of trials with a low risk of bias found no beneficial or detrimental effect of BCAA on mortality. Trial sequential analysis showed that the required information size was not reached, suggesting that additional evidence was needed. BCAA had a beneficial effect on hepatic encephalopathy (RR 0.73, 95% CI 0.61 to 0.88; 827 participants; 16 trials; high quality of evidence). We found no small-study effects and confirmed the beneficial effect of BCAA in a sensitivity analysis that only included trials with a low risk of bias (RR 0.71, 95% CI 0.52 to 0.96). The trial sequential analysis showed that firm evidence was reached. In a fixed-effect meta-analysis, we found that BCAA increased the risk of nausea and vomiting (RR 5.56; 2.93 to 10.55; moderate quality of evidence). We found no beneficial or detrimental effects of BCAA on nausea or vomiting in a random-effects meta-analysis or on quality of life or nutritional parameters. We did not identify predictors of the intervention effect in the subgroup, sensitivity, or meta-regression analyses. In sensitivity analyses that excluded trials with a lactulose or neomycin control, BCAA had a beneficial effect on hepatic encephalopathy (RR 0.76, 95% CI 0.63 to 0.92). Additional sensitivity analyses found no difference between BCAA and lactulose or neomycin (RR 0.66, 95% CI 0.34 to 1.30).

AUTHORS' CONCLUSIONS

In this updated review, we included five additional trials. The analyses showed that BCAA had a beneficial effect on hepatic encephalopathy. We found no effect on mortality, quality of life, or nutritional parameters, but we need additional trials to evaluate these outcomes. Likewise, we need additional randomised clinical trials to determine the effect of BCAA compared with interventions such as non-absorbable disaccharides, rifaximin, or other antibiotics.

Branched-chain amino acids for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a brain dysfunction with neurological and psychiatric changes associated with liver insufficiency or portal-systemic shunting. The severity ranges from minor symptoms to coma. A Cochrane systematic review including 11 randomised clinical trials on branched-chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy.

SEARCH METHODS

We identified trials through manual and electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index (August 2015).

SELECTION CRITERIA

We included randomised clinical trials, irrespective of the bias control, language, or publication status.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data based on published reports and collected data from the primary investigators. We changed our primary outcomes in this update of the review to include mortality (all cause), hepatic encephalopathy (number of people without improved manifestations of hepatic encephalopathy), and adverse events. The analyses included random-effects and fixed-effect meta-analyses. We performed subgroup, sensitivity, regression, and trial sequential analyses to evaluate sources of heterogeneity (including intervention, and participant and trial characteristics), bias (using The Cochrane Hepato-Biliary Group method), small-study effects, and the robustness of the results after adjusting for sparse data and multiplicity. We graded the quality of the evidence using the GRADE approach.

MAIN RESULTS

We found 16 randomised clinical trials including 827 participants with hepatic encephalopathy classed as overt (12 trials) or minimal (four trials). Eight trials assessed oral BCAA supplements and seven trials assessed intravenous BCAA. The control groups received placebo/no intervention (two trials), diets (10 trials), lactulose (two trials), or neomycin (two trials). In 15 trials, all participants had cirrhosis. We classed seven trials as low risk of bias and nine trials as high risk of bias (mainly due to lack of blinding or for-profit funding). In a random-effects meta-analysis of mortality, we found no difference between BCAA and controls (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.69 to 1.11; 760 participants; 15 trials; moderate quality of evidence). We found no evidence of small-study effects. Sensitivity analyses of trials with a low risk of bias found no beneficial or detrimental effect of BCAA on mortality. Trial sequential analysis showed that the required information size was not reached, suggesting that additional evidence was needed. BCAA had a beneficial effect on hepatic encephalopathy (RR 0.73, 95% CI 0.61 to 0.88; 827 participants; 16 trials; high quality of evidence). We found no small-study effects and confirmed the beneficial effect of BCAA in a sensitivity analysis that only included trials with a low risk of bias (RR 0.71, 95% CI 0.52 to 0.96). The trial sequential analysis showed that firm evidence was reached. In a fixed-effect meta-analysis, we found that BCAA increased the risk of nausea and vomiting (RR 5.56; 2.93 to 10.55; moderate quality of evidence). We found no beneficial or detrimental effects of BCAA on nausea or vomiting in a random-effects meta-analysis or on quality of life or nutritional parameters. We did not identify predictors of the intervention effect in the subgroup, sensitivity, or meta-regression analyses. In sensitivity analyses that excluded trials with a lactulose or neomycin control, BCAA had a beneficial effect on hepatic encephalopathy (RR 0.76, 95% CI 0.63 to 0.92). Additional sensitivity analyses found no difference between BCAA and lactulose or neomycin (RR 0.66, 95% CI 0.34 to 1.30).

AUTHORS' CONCLUSIONS

In this updated review, we included five additional trials. The analyses showed that BCAA had a beneficial effect on hepatic encephalopathy. We found no effect on mortality, quality of life, or nutritional parameters, but we need additional trials to evaluate these outcomes. Likewise, we need additional randomised clinical trials to determine the effect of BCAA compared with interventions such as non-absorbable disaccharides, rifaximin, or other antibiotics.

Branched-chain amino acids for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a brain dysfunction with neurological and psychiatric changes associated with liver insufficiency or portal-systemic shunting. The severity ranges from minor symptoms to coma. A Cochrane systematic review including 11 randomised clinical trials on branched-chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy.

SEARCH METHODS

We identified trials through manual and electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index on 2 October 2014.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of the bias control, language, or publication status.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data based on published reports and collected data from the primary investigators. We changed our primary outcomes in this update of the review to include mortality (all cause), hepatic encephalopathy (number of people without improved manifestations of hepatic encephalopathy), and adverse events. The analyses included random-effects and fixed-effect meta-analyses. We performed subgroup, sensitivity, regression, and trial sequential analyses to evaluate sources of heterogeneity (including intervention, and participant and trial characteristics), bias (using The Cochrane Hepato-Biliary Group method), small-study effects, and the robustness of the results after adjusting for sparse data and multiplicity. We graded the quality of the evidence using the GRADE approach.

MAIN RESULTS

We found 16 randomised clinical trials including 827 participants with hepatic encephalopathy classed as overt (12 trials) or minimal (four trials). Eight trials assessed oral BCAA supplements and seven trials assessed intravenous BCAA. The control groups received placebo/no intervention (two trials), diets (10 trials), lactulose (two trials), or neomycin (two trials). In 15 trials, all participants had cirrhosis. Based on the combined Cochrane Hepato-Biliary Group score, we classed seven trials as low risk of bias and nine trials as high risk of bias (mainly due to lack of blinding or for-profit funding). In a random-effects meta-analysis of mortality, we found no difference between BCAA and controls (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.69 to 1.11; 760 participants; 15 trials; moderate quality of evidence). We found no evidence of small-study effects. Sensitivity analyses of trials with a low risk of bias found no beneficial or detrimental effect of BCAA on mortality. Trial sequential analysis showed that the required information size was not reached, suggesting that additional evidence was needed. BCAA had a beneficial effect on hepatic encephalopathy (RR 0.73, 95% CI 0.61 to 0.88; 827 participants; 16 trials; high quality of evidence). We found no small-study effects and confirmed the beneficial effect of BCAA in a sensitivity analysis that only included trials with a low risk of bias (RR 0.71, 95% CI 0.52 to 0.96). The trial sequential analysis showed that firm evidence was reached. In a fixed-effect meta-analysis, we found that BCAA increased the risk of nausea and vomiting (RR 5.56; 2.93 to 10.55; moderate quality of evidence). We found no beneficial or detrimental effects of BCAA on nausea or vomiting in a random-effects meta-analysis or on quality of life or nutritional parameters. We did not identify predictors of the intervention effect in the subgroup, sensitivity, or meta-regression analyses. In sensitivity analyses that excluded trials with a lactulose or neomycin control, BCAA had a beneficial effect on hepatic encephalopathy (RR 0.76, 95% CI 0.63 to 0.92). Additional sensitivity analyses found no difference between BCAA and lactulose or neomycin (RR 0.66, 95% CI 0.34 to 1.30).

AUTHORS' CONCLUSIONS

In this updated review, we included five additional trials. The analyses showed that BCAA had a beneficial effect on hepatic encephalopathy. We found no effect on mortality, quality of life, or nutritional parameters, but we need additional trials to evaluate these outcomes. Likewise, we need additional randomised clinical trials to determine the effect of BCAA compared with interventions such as non-absorbable disaccharides, rifaximin, or other antibiotics.

Branched-chain amino acids alter neurobehavioral function in rats

Recently, we have described a strong association of branched-chain amino acids (BCAA) and aromatic amino acids (AAA) with obesity and insulin resistance. In the current study, we have investigated the potential impact of BCAA on behavioral functions. We demonstrate that supplementation of either a high-sucrose or a high-fat diet with BCAA induces anxiety-like behavior in rats compared with control groups fed on unsupplemented diets. These behavioral changes are associated with a significant decrease in the concentration of tryptophan (Trp) in brain tissues and a consequent decrease in serotonin but no difference in indices of serotonin synaptic function. The anxiety-like behaviors and decreased levels of Trp in the brain of BCAA-fed rats were reversed by supplementation of Trp in the drinking water but not by administration of fluoxetine, a selective serotonin reuptake inhibitor, suggesting that the behavioral changes are independent of the serotonergic pathway of Trp metabolism. Instead, BCAA supplementation lowers the brain levels of another Trp-derived metabolite, kynurenic acid, and these levels are normalized by Trp supplementation. We conclude that supplementation of high-energy diets with BCAA causes neurobehavioral impairment. Since BCAA are elevated spontaneously in human obesity, our studies suggest a potential mechanism for explaining the strong association of obesity and mood disorders.

The effects of 8 weeks of heavy resistance training and branched-chain amino acid supplementation on body composition and muscle performance

PURPOSE

This study determined the effects of 8 weeks of heavy resistance training combined with branched-chain amino acid (BCAA) supplementation on body composition and muscle performance.

METHODS

Resistance training was performed by 19 non-resistance-trained males (three sets of 8-10 repetitions) four times/week, for 8 weeks, while also ingesting 9 g/day of BCAA or 9 g/day of placebo (PLAC) on the exercise days only (one-half of total dose 30 min before and after exercise). Data were analyzed with separate 2 × 2 analysis of variance (ANOVA) (p < 0.05).

RESULTS

For total body mass, neither group significantly increased with training (p = 0.593) and also, there were no significant changes in total body water (p = 0.517). In addition, no training- or supplement-induced (p = 0.783) changes occurred with fat mass or fat-free mass (p = 0.907). Upper-body (p = 0.047) and lower-body strength (p = 0.044) and upper- (p = 0.001) and lower-body muscle endurance (p = 0.013) increased with training; however, these increases were not different between the groups (p > 0.05).

CONCLUSION

When combined with heavy resistance training for 8 weeks, supplementation with 9 g/day of BCAA 30 min before and after exercise had no preferential effects on body composition and muscle performance.

DNA damage in an animal model of maple syrup urine disease

Maple syrup urine disease is an inborn error of metabolism caused by a severe deficiency of the branched chain alpha-ketoacid dehydrogenase complex. Neurological dysfunction is a common finding in patients with maple syrup urine disease. However, the mechanisms underlying the neuropathology of brain damage in this disorder are poorly understood. In this study, we investigated whether acute or chronic administration of a branched chain amino acid pool (leucine, isoleucine and valine) causes transient DNA damage, as determined by the alkaline comet assay, in the brain and blood of rats during development and whether antioxidant treatment prevented the alterations induced by branched chain amino acids. Our results showed that the acute administration of branched chain amino acids increased the DNA damage frequency and damage index in the hippocampus. However, the chronic administration of branched chain amino acids increased the DNA damage frequency and damage index in both the hippocampus and the striatum, and the antioxidant treatment was able to prevent DNA damage in the hippocampus and striatum. The present study demonstrated that metabolite accumulation in MSUD induces DNA damage in the hippocampus and striatum and that it may be implicated in the neuropathology observed in the affected patients. We demonstrated that the effect of antioxidant treatment (N-acetylcysteine plus deferoxamine) prevented DNA damage, suggesting the involvement of oxidative stress in DNA damage.

[Sport's medicalization]

Medicalization (abuse of sport drinks, supplements and drugs) involves more and more of the sport world, casting doubt on the credibility of results. causes and responsibilities are individuated. Characteristics of two commonly used supplements (creatine, branched-chain amino acids) are analyzed in order to show risks and ambiguities for athletes and the way to come out of it.

Role of branched-chain amino acids in liver disease: the evidence for and against

PURPOSE OF REVIEW

There is ample evidence that patients with liver disease have an ongoing energy and protein catabolism. Nutritional management in these patients must receive high priority. The administration of branched-chain amino acids to patients with liver disease has been a controversial subject. This review is an update on the data available from various studies involving branched-chain amino acids supplementation in patients with chronic liver disease and associated complications.

RECENT FINDINGS

This review summarizes the results of nutritional interventions involving branched-chain amino acids supplementation carried out in different centres around the world. It is interesting to note that no toxic effects of branched-chain amino acids supplementation have been reported in any of these trials.

SUMMARY

Administration of branched-chain amino acids stimulates hepatic protein synthesis in patients with chronic liver disease and this could contribute significantly to improving their nutritional status, and result in a better quality of life. The beneficial role of branched-chain amino acids supplementation in patients with chronic hepatic encephalopathy has been clearly documented in some studies but the exact mechanism of action is still not clear.

Markers associated with inborn errors of metabolism of branched-chain amino acids and their relevance to upper levels of intake in healthy people: an implication from clinical and molecular investigations on maple syrup urine disease

Maple syrup urine disease (MSUD) is caused by a deficiency in the branched-chain alpha-ketoacid dehydrogenase complex. Accumulations of branched-chain amino acids (BCAAs) and branched-chain alpha-ketoacids (BCKAs) in patients with MSUD induce ketoacidosis, neurological disorders, and developmental disturbance. BCAAs and BCKAs influence on the nervous system can be estimated by analyzing these patients. According to clinical investigations on MSUD patients, leucine levels over 400 micromol/L apparently can cause any clinical problem derived from impaired function of the central nervous system. Damage to neuronal cells found in MSUD patients are presumably because of higher concentrations of both blood BCAAs or BCKAs, especially alpha-ketoisocapronic acids. These clinical data from MSUD patients provide a valuable basis on understanding leucine toxicity in the normal subject.

Tolerance for branched-chain amino acids in experimental animals and humans

There is no good evidence for establishing branched-chain amino acid (BCAA) tolerance levels for humans. With pigs, chicks, and rats, data are available concerning excessive intake levels of BCAA, but most of the information is for growing animals instead of for adults. Estimates of maintenance requirements for (high-quality) protein and BCAA in pigs weighing between 43 and 140 kg are 350 mg . kg(-1) . d(-1) for protein and 28.7 mg . kg(-1) . d(-1) for total BCAA. In contrast, human adult maintenance requirement estimates are much higher, i.e., 660 mg . kg(-1) . d(-1) for good quality protein and a range of 68 to 144 mg . kg(-1) . d(-1) for total BCAA. The human maintenance BCAA requirement estimates range from 10.3 to 22% of the maintenance protein requirement. Whole-body protein of 45-kg pigs contains 14.2 g BCAA/100 g protein, but the maintenance requirement (based on nitrogen balance) for total BCAA is only 8.2% of the total maintenance protein requirement. Conversely, sulfur amino acid (methionine + cysteine), threonine, and tryptophan maintenance requirements of pigs as a percentage of the maintenance protein requirement are much higher than whole-body protein levels of these amino acids. This suggests that the efficiency of using absorbed amino acids of dietary origin or of reusing endogenous amino acids arising from body protein catabolism may vary considerably among the indispensable amino acids. Additionally, work with pigs points to the conclusion that whole-body amino acid concentrations are poor predictors of both maintenance requirements and ideal amino acid profiles. Based on studies with young experimental animals, a rather large dietary excess (above requirement) of an individual BCAA is well tolerated when consumed in diets containing surfeit levels of protein and the other 2 BCAA.

Proteins and amino acid supplementation in sports: are they truly necessary?

Although dietary protein supplementation is commonly used by both athletes and people engaged in recreational sports, the data supporting its wide use are still limited. Some evidence supports the use of creatine and possibly HMB as ergogenic aids in specific situations [8], however this is also based on limited data. The use of supplements for the healthy, non-competitive adult engaged in recreational sports is usually not warranted.

Suppression of the bitterness of enteral nutrients using increased particle sizes of branched-chain amino acids (BCAAs) and various flavours: a taste sensor study

An improved formulation of the enteral nutrient Aminoleban EN (Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan), has been commercially available since Spring 2004. Like the previous formulation, the improved product contains branched-chain amino acids (BCAAs) L-isoleucine (L-Ile), L-leucine (L-Leu), and L-valine (L-Val), but the average particle size of these amino acids has been increased to 180 to 250 microm in the improved formulation, compared with 40 to 90 microm in the old product. The improved formulation has a significantly lower bitterness intensity score than the older formulation, as evaluated both in human gustatory tests and using the artificial taste sensor. We propose that this improved taste masking is due to the larger particle size of the BCAA crystals, due to which their release rates are reduced. The addition of improved flavours has also helped to reduce the bitterness of the improved Aminoleban EN formulation significantly. Analysis of the taste sensor data suggests that the sourness and sweetness of the added flavours were critical in diminishing the bitterness of Aminoleban EN.

Exercise promotes BCAA catabolism: effects of BCAA supplementation on skeletal muscle during exercise

Branched-chain amino acids (BCAAs) are essential amino acids that can be oxidized in skeletal muscle. It is known that BCAA oxidation is promoted by exercise. The mechanism responsible for this phenomenon is attributed to activation of the branched-chain alpha-keto acid dehydrogenase (BCKDH) complex, which catalyzes the second-step reaction of the BCAA catabolic pathway and is the rate-limiting enzyme in the pathway. This enzyme complex is regulated by a phosphorylation-dephosphorylation cycle. The BCKDH kinase is responsible for inactivation of the complex by phosphorylation, and the activity of the kinase is inversely correlated with the activity state of the BCKDH complex, which suggests that the kinase is the primary regulator of the complex. We found recently that administration of ligands for peroxisome proliferator-activated receptor-alpha (PPARalpha) in rats caused activation of the hepatic BCKDH complex in association with a decrease in the kinase activity, which suggests that promotion of fatty acid oxidation upregulates the BCAA catabolism. Long-chain fatty acids are ligands for PPARalpha, and the fatty acid oxidation is promoted by several physiological conditions including exercise. These findings suggest that fatty acids may be one of the regulators of BCAA catabolism and that the BCAA requirement is increased by exercise. Furthermore, BCAA supplementation before and after exercise has beneficial effects for decreasing exercise-induced muscle damage and promoting muscle-protein synthesis; this suggests the possibility that BCAAs are a useful supplement in relation to exercise and sports.

Double-blind crossover study of branched-chain amino acid therapy in patients with spinocerebellar degeneration

To determine whether treatment with branched-chain amino acids (BCAA) can improve the condition of patients with ataxia, a double-blind crossover study of BCAA therapy was performed in 16 patients with spinocerebellar degeneration (SCD). The patients were treated with BCAA in oral doses of 1.5, 3.0, or 6.0 g or with placebo daily for 4 weeks in each study phase. The order of treatment phases (placebo or BCAA) was assigned randomly. An International Cooperative Ataxia Rating Scale (ICARS) was used to quantify the severity of symptoms of SCD. The mean ICARS score improved significantly with BCAA treatment compared with the mean pretreatment score (p<0.01). In addition, the improvement in the mean global ICARS score was significant in the middle-dose group compared with that in the placebo group (p<0.02). The estimated improvement in kinetic functions compared with pretreatment (p<0.01) was significant after treatment with BCAA, 1.5 and 3.0 g. All of the responders manifested predominantly cerebellar symptoms, especially those with spinocerebellar ataxia type 6 (SCA6). Thus, treatment with BCAA may be effective in patients with the cerebellar form of SCD.

Oral supplementation of branched-chain amino acid improves nutritional status in elderly patients on chronic haemodialysis

BACKGROUND

Anorexia may be associated with decreased plasma levels of branched-chain amino acids (BCAA). In malnourished elderly haemodialysis (HD) patients, oral BCAA supplementation may improve anorexia, resulting in improved nutritional status.

METHODS

Among 44 elderly (age >70 years) patients on chronic HD, 28 patients with low plasma albumin concentration (<3.5 g/dl) were classified as the malnourished group; they also suffered from anorexia. The other 16 patients did not complain of anorexia and were classified as the well-nourished group. We performed a 12-month, placebo-controlled, double-blind study on the malnourished group. Fourteen patients each received daily oral BCAA supplementation (12 g/day) or a placebo in random order in a crossover trial for 6 months. Body fat percentage, lean body mass, plasma albumin concentration, dietary protein and caloric intakes, and plasma amino acid profiles were monitored.

RESULTS

Lower plasma levels of BCAA and lower protein and caloric intakes were found in the malnourished group as compared to the well-nourished group. In BCAA-treated malnourished patients, anorexia and poor oral protein and caloric intakes improved within a month concomitant with the improvement in plasma BCAA levels over the values in well-nourished patients. After 6 months of BCAA supplementation, anthropometric indices showed a statistically significant increase and mean plasma albumin concentration increased from 3.31 g/dl to 3.93 g/dl. After exchanging BCAA for a placebo, spontaneous oral food intake decreased, but the favourable nutritional status persisted for the next 6 months. In 14 patients initially treated with a placebo, no significant changes in nutritional parameters were observed during the first 6 months. However, positive results were obtained by BCAA supplementation during the subsequent 6 months, and mean plasma albumin concentration increased from 3.27 g/dl to 3.81 g/dl.

CONCLUSIONS

Normalization of low plasma levels of BCAA by oral supplementation can reduce anorexia and significantly improve overall nutritional status in elderly malnourished HD patients.

Short-term effects of branched-chain amino acids on liver function tests in cirrhotic patients

A randomized study was conducted in 29 ambulatory cirrhotic patients to determine the short-term effects of branched-chain amino acids (BCAA) on nutritional status, biochemical liver function tests and caffeine clearance. Each patient received a 4-week period of isonitrogenous and isocaloric regimens, either a standardized diet contained 40 g protein with supplementation of BCAA 150 g daily (group I) or only a standardized diet contained 80 g protein daily (group II). At the end of treatment, only group I showed significant improvements in transaminase levels as well as the caffeine clearance test compared with those of the pre-treatment levels. Nonetheless, significant improvements in nutritional parameters and additional liver function tests were not yet detected. We conclude that the short-term nutritional supplementation of BCAA is well tolerated and leads to improvement in hepatic metabolic capacity assessed by the caffeine clearance test.

Long-term oral administration of branched chain amino acids after curative resection of hepatocellular carcinoma: a prospective randomized trial. The San-in Group of Liver Surgery

BACKGROUND

Live cirrhosis is a state of protein calorie malnutrition which may induce various complications. This study aimed to elucidate if long-term nutritional support with branched chain amino acids (BCAAs) is effective after hepatic resection for hepatocellular carcinoma (HCC).

METHODS

Between 2 and 3 weeks after operation, 75 patients were randomized to receive oral BCAAs (Aminoleban EN) 100 g per day for 1 year, and another 75 patients were assigned to a control group. Mean follow-up times were 35.8 months and 36.0 months respectively.

RESULTS

Flapping tremor was less common, body-weight was greater and performance status was better in the BCAA-treated group throughout the 1-year period. BCAA treatment significantly increased red blood cell and serum albumin level in patients with Child grade B and C disease. Substantially similar effects were observed in those with major hepatic resection. Higher Fischer molar ratios were maintained in the treated group. However, there were no differences in cumulative tumour recurrence and survival rates.

CONCLUSION

Long-term oral nutritional support with BCAAs after resection of HCC is beneficial in improving clinical features and laboratory data without increasing the rate of tumour recurrence, particularly in patients with advanced cirrhosis or after major hepatic resection.

Branched-chain amino acids and amyotrophic lateral sclerosis: a treatment failure? The Italian ALS Study Group

We initiated a double-blind, placebo-controlled trial to test the efficacy and safety of branched-chain amino acids (BCAA) (L-leucine 12 g, L-isoleucine 6 g, and L-valine 6 g daily) in amyotrophic lateral sclerosis (ALS) patients. There was an excess mortality in subjects randomized to active treatment (24 BCAA, 13 placebo) when a total of 126 ALS patients had been recruited. This finding, associated with the lack of efficacy of BCAA (measured by comparing the disability scales in the two treatment groups), led the Data Monitoring Committee to require cessation of the trial.

[Glucose utilization and risk of hyperglycemia during simultaneous administration of branched-chain amino acids and fat emulsions in healthy persons]

In order to evaluate the effect of substrate competition on glucose utilization, we studied 8 healthy volunteers under three different conditions: 1. Hyperinsulinemic (75 a 550 microU/ml) euglycemic (5 mmol/1) clamp (HEC). 2. HEC with Nutramin VLI infusion given at a rate of 2 ml/kg.h. 3. HEC with infusion of Nutramin VLI (2 ml/kg.h) and Intralipid (0.15 g of fat/kg.h). Glucose utilization was evaluated as the glucose disposal rate during HEC. We have found, that Nutramin VLI given alone or with Intralipid does not significantly decrease glucose utilization at insulinemia of about 75 and 550 microU/ml. We conclude that simultaneous administration of substrates during parenteral nutrition at standard rates does not raise the risk of hyperglycemia in healthy men.

Hyperkalaemia during infusion of hyperosmolar amino acid solutions enriched with branched chain amino acids. Report of two cases

We report two cases of unexplained hyperkalaemia during infusion of amino acid solutions enriched with branched chain amino acids. The increase in potassium levels developed 24 hours after starting infusion and normalization was obtained within 24 hours after stopping infusion. Acidosis, acute renal failure, concomitant cell destruction and haemolysis were excluded; antialdosteronic diuretics were not given. The authors hypothesize that hyperkalaemia could be due to a sudden increase in plasmatic osmolality caused by the hyperosmolarity (900 mOsm/l) of the solution, not counterbalanced by adequate ADH release owing to malfunctioning of hypothalamic osmoreceptors. At present this hypothesis is lacking in experimental proofs.

[Adverse effects of branched chain amino acid transfusion on type-II citrullinemia--report of an adult case]

A 24-year-old man was admitted to our hospital, because two days before the admission he had abruptly lost consciousness following generalized convulsive seizures. He had a past history of transient amnesia and a favor for peanuts. His grandparents had a record of consanguinity. On admission, he was comatose and flaccid with his four extremities. Laboratory examination revealed the followings; mild degree of abnormal liver function, slight elevation of blood ammonia, irregular theta basic rhythm on EEG, marked brain edema on CT and a normal liver ultrasonography. From the second hospital day, in addition to antiepileptic drugs and adrenocorticosteroids, branched chain amino acid was administered to reactivate damaged brain functions. Thereafter, the concentration of blood ammonia increased to more than 3,000 micrograms/dl, and as a result he fell into status epilepticus. On the fourth hospital day, the levels of citrulline in the plasma and urine taken on the first hospital day were found to have increased by 20 and 100 times, respectively. Although the transfusion of branched chain amino acid was stopped, he died while in coma on the 12th hospital day. Enzymatic analyses of necropsied liver specimens revealed that the quantitative activity of argininosuccinate synthetase had decreased to less than 10% in his urea cycle. In this patient, it was noted that, after transfusion of branched chain amino acid, his brain activities turned worse and blood ammonia was markedly elevated. There is a possibility that intravenous administration of branched chain amino acid may interrupt the urea cycle balance in an adult patient of citrullinemia with dysfunction of the brain, kidney and muscle, especially with brain edema.(ABSTRACT TRUNCATED AT 250 WORDS)

[2 cases of metabolic acidosis during therapy of portosystemic encephalopathy with branched-chain amino acids]

Two patients known to be suffering from liver cirrhosis were admitted to hospital in a state of coma. The apparent ineffectiveness of treatment with branched chain amino acids was found in reality to be due to the onset of metabolic acidosis. The suspension of treatment and balancing of the metabolic imbalance with an infusion of bicarbonate solutions led to lessening of the neurological symptomatology.

Use of a branched chain amino acid enriched solution in patients under metabolic stress

The metabolic response to stress results in proteolysis, increased gluconeogenesis, and negative nitrogen balance. Infusion of BCAA has been shown experimentally to decrease protein degradation and stimulate protein synthesis. Such infusion may modify the response of patients to metabolic stress. An amino acid solution containing 45 percent BCAA as a component of central vein parenteral nutrition was infused into 20 moderately to severely stressed postoperative patients in a prospective, nonrandomized fashion. Infusion was begun within 24 hours postoperatively and continued for 7 to 14 days. Patients received 1.6 g protein equivalents per kg body weight daily and 30 kcal/kg body weight daily. Nutritional indexes as measured by albumin and transferrin values were maintained during the study period. Nitrogen balance became increasingly positive over the period of infusion without an increase in the urinary excretion of 3-methylhistidine. There were no serious clinical or biochemical side effects of the BCAA infusion, although a statistically significant increase in alkaline phosphatase was observed. These results suggest that central vein parenteral nutrition utilizing a 45 percent BCAA enriched solution can promote nitrogen retention without serious side effects in moderately to severely stressed patients.