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Branched-chain amino acids (BCAAs) are essential amino acids that play a crucial role in regulating animal physiology and metabolism. The lack of sensitive, rapid, and portable methods for measuring BCAA concentrations in blood samples hinders precise and dynamic monitoring of nutritional status during swine production. In this work, a paper-based analytical device (PAD) was developed for quantifying BCAAs in blood samples. The device utilized a redox reaction between BCAAs and NAD+ catalyzed by leucine dehydrogenase, producing NADH that could be detected by NADH-responsive polymer dots with high selectivity, sensitivity, and accuracy. A separation membrane was incorporated in the PAD for spontaneous blood-plasma separation. The fluorescent images were captured by using a smartphone. It required only 20 μL of blood volume, and the entire assay could be completed in less than 5 minutes. The quantitation range spanned from 35 μM to 1000 μM, covering the normal BCAA concentration range in porcine bloods. The BCAA concentration measured with the PAD assay was in good agreement with those obtained with an ELISA kit. In sum, this PAD-based BCAA assay offers a point-of-care testing approach for monitoring BCAA levels in pig production, especially with a low-protein diet. • A portable paper-based analytical device was developed for BCAAs quantification. • The NADH-sensitive polymer dots were utilized as the ratiometric fluorescent probe. • A ratiometric fluorescent assay was achieved by using a smartphone. • Total BCAA level in pig blood was accurately determined. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel paper test strip platform was proposed for BCAAs detection. • A colorimetric analysis was achieved by using a smartphone. • The silver nanoparticles exhibited enhance the colorimetric detection. • The proposed assay was successfully applied to detect BCAAs in edible insects. • This paper test strip provided multiple advantages than traditional method. A novel strategy is presented for simple, sensitive and selective branched-chain amino acids (BCAAs) detection in edible insects on a paper test strip device readout with a smartphone. Silver nanoparticles (AgNPs) were applied, interacting with dye, which provided 1.5 times higher color intensity than the one without AgNPs. The proposed paper test strip exhibiting the detection limit of leucine, isoleucine and valine were 6.0, 6.2 and 7.2 mg/L, respectively. The linear dynamic ranges were 20–120 mg/L for leucine and 20–110 mg/L for isoleucine and valine detections. The proposed paper test strip was successfully applied for the detection of BCAAs in edible insects. The analytical results obtained using paper test strips were in good agreement with those obtained via a commercial test kit. This study shows the successful integration of the paper test strip and the smartphone to afford an easy-to-use, inexpensive and portable device alternative for BCAAs analysis. [ABSTRACT FROM AUTHOR]

Obesity and its related diseases, such as type 2 diabetes (T2DM), cardiovascular disease (CVD), and metabolic fatty liver disease (MAFLD), require new diagnostic markers for earlier detection and intervention. The aim of this study is to demonstrate the potential of metabolomics as a tool for identifying biomarkers associated with obesity and its comorbidities in every age group. The presented systematic review makes an important contribution to the understanding of the potential of metabolomics in identifying biomarkers of obesity and its complications, especially considering the influence of branched-chain amino acids (BCAAs), amino acids (AAs) and adipokines on the development of T2DM, MAFLD, and CVD. The unique element of this study is the combination of research results from the last decade in different age groups and a wide demographic range. The review was based on the PubMed and Science Direct databases, and the inclusion criterion was English-language original studies conducted in humans between 2014 and 2024 and focusing on the influence of BCAAs, AAs or adipokines on the above-mentioned obesity complications. Based on the PRISMA protocol, a total of 21 papers were qualified for the review and then assigned to a specific disease entity. The collected data reveal that elevated levels of BCAAs and some AAs strongly correlate with insulin resistance, leading to T2DM, MAFLD, and CVD and often preceding conventional clinical markers. Valine and tyrosine emerge as potential markers of MAFLD progression, while BCAAs are primarily associated with insulin resistance in various demographic groups. Adipokines, although less studied, offer hope for elucidating the metabolic consequences of obesity. The review showed that in the case of CVDs, there is still a lack of studies in children and adolescents, who are increasingly affected by these diseases. Moreover, despite the knowledge that adipokines play an important role in the pathogenesis of obesity, there are no precise findings regarding the correlation between individual adipokines and T2DM, MAFLD, or CVD. In order to be able to introduce metabolites into the basic diagnostics of obesity-related diseases, it is necessary to develop panels of biochemical tests that will combine them with classical markers of selected diseases. [ABSTRACT FROM AUTHOR]

Despite the emergence of many therapies aimed at combating cancer, the disease provides an overwhelming global concern. Recently, the metabolism of cancer cells has been identified as an essential factor in cancer progression. The metabolism of cancer is regulated through specific dietary interventions. Further, oxidative stress plays a key role in the initiation and progression of cancer, and its impact can be influenced by tumor metabolism remodeling. Branched-chain amino acids (BCAAs), which have been shown to have functions beyond protein synthesis and energy production, are now recognized as critical regulators of oxidative stress in tumor cells. In this paper, we aim to discuss the role of BCAAs in regulating oxidative stress in tumor cells. Our study involved using prostate and renal cancer cell lines to assess the expression of anti-oxidative stress enzymes after supplementing different amino acids. Our study's results suggest that amino acids' effect on oxidative stress and signaling activation depends on the cell line and type of cancer. Our findings highlight the importance of using nutrient therapy and dietary interventions with a tailored approach and explicit reference to which kind of cancer is being treated. [ABSTRACT FROM AUTHOR]

Branched-chain amino acids (BCAAs)—leucine (Leu), isoleucine (Ile), and valine (Val)—are essential nutrients with significant roles in protein synthesis, metabolic regulation, and energy production. This review paper offers a detailed examination of the physico-chemical properties of BCAAs, their industrial synthesis, and their critical functions in various biological processes. The unique isomerism of BCAAs is presented, focusing on analytical challenges in their separation and quantification as well as their solubility characteristics, which are crucial for formulation and purification applications. The industrial synthesis of BCAAs, particularly using bacterial strains like Corynebacterium glutamicum, is explored, alongside methods such as genetic engineering aimed at enhancing production, detailing the enzymatic processes and specific precursors. The dietary uptake, distribution, and catabolism of BCAAs are reviewed as fundamental components of their physiological functions. Ultimately, their multifaceted impact on signaling pathways, immune function, and disease progression is discussed, providing insights into their profound influence on muscle protein synthesis and metabolic health. This comprehensive analysis serves as a resource for understanding both the basic and complex roles of BCAAs in biological systems and their industrial application. [ABSTRACT FROM AUTHOR]

Branched-chain amino acid aminotransferases, widely present in natural organisms, catalyze bidirectional amino transfer between branched-chain amino acids and branched-chain a-ketoacids in cells. Branched-chain amino acid aminotransferases play an important role in the metabolism of branchedchain amino acids. In this paper, the interspecific evolution and biological characteristics of branched-chain amino acid aminotransferases are introduced, the related research of branched-chain amino acid aminotransferases in animals, plants, microorganisms and humans is summarized and the molecular mechanism of branched-chain amino acid aminotransferase is analyzed. It has been found that branched-chain amino acid metabolism disorders are closely related to various diseases in humans and animals and plants, such as diabetes, cardiovascular diseases, brain diseases, neurological diseases and cancer. In particular, branched-chain amino acid aminotransferases play an important role in the development of various tumors. Branched-chain amino acid aminotransferases have been used as potential targets for various cancers. This article reviews the research on branched-chain amino acid aminotransferases, aiming to provide a reference for clinical research on targeted therapy for various diseases and different cancers. [ABSTRACT FROM AUTHOR]

Background: Abdominal obesity (AO) is linked to reduced health status and mortality. While it is known that AO is prevalent in chronic obstructive pulmonary disease (AO-COPD), the specific metabolic and functional consequences associated with AO-COPD remain understudied. Methods: We studied 199 older adults with COPD and 168 control subjects with and without AO and assessed visceral adipose tissue (VAT) by dual-energy X-ray absorptiometry. VAT > 70th percentile of the control group qualified a subject as AO in a sex specific manner. We measured plasma concentrations and whole body production (WBP) rates of multiple amino acids to assess the metabolic profile. We assessed medical history, body composition by Dual-Energy X-ray Absorptiometry, muscle strength, and cognitive function. We performed statistics by analysis of covariance (p) and FDR (q) for multiple comparisons. Results: AO-COPD subjects had 27% more VAT (q < 0.01) than AO-Control subjects despite correction for BMI. Branched-chain amino acid concentrations and WBP rates were generally elevated in AO-COPD but whole body clearance rate was only elevated in COPD. Metabolic syndrome comorbidities (p < 0.01) and systemic inflammation (P < 0.05) were most prevalent in the AO-COPD group. Muscle strength was reduced in COPD subjects (p < 0.001), but partially preserved when combined with AO. Cognitive dysfunction and mood disturbances were present in COPD subjects (p < 0.001) with worst performers in AO-COPD (q < 0.05). Conclusion: The presence of AO is associated with specific metabolic and functional phenotypes in COPD. Clinical trial registry Trial registration ClinicalTrials.gov. In the present paper, we report an analysis of the baseline measurements of COPD subjects and healthy controls from the study numbers: NCT01787682, NCT01787682, NCT02157844, NCT02082418, NCT02065141, NCT02770092, NCT02908425, NCT03159390, NCT02780219, NCT03327181, NCT03796455, NCT04928872, NCT04461236, NCT01173354, NCT01154400. [ABSTRACT FROM AUTHOR]

Branched‐chain amino acids (BCAAs), leucine, isoleucine and valine have an enormous functional significance because of their involvement in fish physiology. Branched‐chain amino acids are not limited to act as substrates of protein synthesis but are also part of the protein synthesis regulation. BCAAs regulate various key signalling pathways. Leucine has a pivotal role in mTOR activation, while isoleucine and valine have a predominant energy and glucose metabolism action. Research over the years has highlighted the importance of dietary BCAAs levels on the growth and development of fish. The available data suggest that fish require slightly higher amounts of BCAAs at the initial stage than at the latter stages of life. BCAAs requirements of different fish species have indicated wide variations: 11.5 to 91.0 g leucine/kg dietary protein, 15.4 to 42.3 g isoleucine/kg dietary protein and 17.7 to 46.91 g valine/kg dietary protein. This review paper covers the dietary BCAA requirements of various fish species and the modulation action of BCAAs on vital functions, as protein synthesis, metabolic pathway, glucose transportation and immune response. [ABSTRACT FROM AUTHOR]

A meta-analysis was conducted to evaluate the effects of branched-chain amino acids (BCAA), their interactions, and interactions with large neutral amino acids (LNAA) to develop prediction equations for growth performance of pigs. Data from 25 papers, published from 1995 to 2018, for a total of 44 trials and 210 observations were recorded in a database. Diets were reformulated using the NRC (2012) loading values to estimate nutrient concentrations. The response variables were average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). The predictor variables tested included average body weight (BW), crude protein, neutral detergent fiber, Ile:Lys, Leu:Lys, Val:Lys, BCAA:Lys, Ile:Leu, Val:Leu, Ile:Val, (Ile+Val):Leu, Trp:Lys, Leu:Trp, Ile:Trp, Val:Trp, BCAA:Trp, Met:Lys, Leu:Met, Ile:Met, Val:Met, BCAA:Met, His:Lys, Leu:His, Ile:His, Val:His, BCAA:His, Thr:Lys, Leu:Thr, Ile:Thr, Val:Thr, BCAA:Thr, (Phe+Tyr):Lys, Leu:(Phe+Tyr), Ile:(Phe+Tyr), Val:(Phe+Tyr), BCAA:(Phe+Tyr), LNAA:Lys, Leu:LNAA, Ile:LNAA, Val:LNAA, and BCAA:LNAA. Amino acids were expressed on standardized ileal digestible basis. The MIXED procedure of SAS (SAS Institute Inc. Cary, NC) was used to develop the equations. The inverse of squared SEM was used to account for heterogeneous errors using the WEIGHT statement. Models were selected with a step-wise manual forward selection. In order to be included in the final model, predictor variables had to be statistically significant (P < 0.05) and provide an improvement of at least 2 points in Bayesian information criterion. The optimum equations were: ADG, g = – 985.94 + (15.2499 × average BW (kg)) – (0.08885 × average BW × average BW) + (1.063 × Leu:Lys) + (20.2659 × Ile:Lys) – (0.1479 × Ile:Lys × Ile:Lys) + (9.2243 × (Ile+Val):Leu) – (0.03321 × (Ile+Val):Leu × (Ile+Val):Leu) – (0.4413 × Ile:Trp); G:F, g/kg = 648.3 – (6.2974 × average BW (kg)) + (0.02051 × average BW × average BW) + (0.5396 × Ile:Lys) + (1.7284 × Val:Lys) – (0.00795 × Val:Lys × Val:Lys) – (1.7594 × Met:Lys); and ADFI, kg = predicted ADG/predicted G:F. Overall, the prediction equations suggest that increasing Leu:Lys negatively impacts ADG due to a reduction in G:F and ADFI caused by insufficient levels of other BCAA and LNAA relative to Leu. According to the model, the addition of Val, Ile, and Trp, alone or in combination, has the potential to counteract the negative effects of high dietary Leu concentrations on growth performance. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to examine the acute effects of branched-chain amino acids (BCAAs)-containing electrolyte beverage (AE) on water–electrolyte balance, muscle damage, time to finish the final 5 km, and muscle strength compared to a standard commercially available carbohydrate–electrolyte sports beverage (CE), pure water (W), and no rehydration (N). Methods: Fourteen trained male participants (20 ± 2 years old) completed four randomized 21 km running trials. The participants were instructed to consume their drink (150 mL W, 150 mL CE, or 150 mL AE) or no rehydration (N) at 5 km, 10 km, and 15 km. Body mass and muscle strength were assessed, and blood samples were collected before and after exercise. Perceptual scales were administered during and after running. Blood electrolyte levels (sodium, potassium, and chloride) and creatine kinase (CK) concentration were analyzed. Results: The change in plasma volume with AE was significantly smaller than that with N (p < 0.05). Consuming AE maintained the best potassium balance (p < 0.05). Twenty-four hours after exercise, serum CK concentrations significantly elevated in N, W, and CE (p < 0.05), but did not reach statistical significance in the AE group (p > 0.05). Compared to N, consuming AE resulted in significantly less soreness 24 h after exercise (p < 0.05). There was no difference in time to finish the final 5 km (p > 0.05). Maximal voluntary isometric force output was significantly lower after exercise with N and W (p < 0.05) but not with CE or AE (p > 0.05). Conclusions: Consuming a BCAAs-containing sports beverage during a 21 km run can help reduce dehydration, maintain potassium balance, lower muscle damage, and prevent the decline in lower limb strength after 21 km running. [ABSTRACT FROM AUTHOR]

Diabetic neuropathic pain (DNP), one of the most common complications of diabetes, is characterized by bilateral symmetrical distal limb pain and substantial morbidity. To compare the differences is aimed at serum metabolite levels between 81 DNP and 73 T2DM patients without neuropathy and found that the levels of branched‐chain amino acids (BCAA) are significantly lower in DNP patients than in T2DM patients. In high‐fat diet/low‐dose streptozotocin (HFD/STZ)‐induced T2DM and leptin receptor‐deficient diabetic (db/db) mouse models, it is verified that BCAA deficiency aggravated, whereas BCAA supplementation alleviated DNP symptoms. Mechanistically, using a combination of RNA sequencing of mouse dorsal root ganglion (DRG) tissues and label‐free quantitative proteomic analysis of cultured cells, it is found that BCAA deficiency activated the expression of L‐type amino acid transporter 1 (LAT1) through ATF4, which is reversed by BCAA supplementation. Abnormally upregulated LAT1 reduced Kv1.2 localization to the cell membrane, and inhibited Kv1.2 channels, thereby increasing neuronal excitability and causing neuropathy. Furthermore, intraperitoneal injection of the LAT1 inhibitor, BCH, alleviated DNP symptoms in mice, confirming that BCAA‐deficiency‐induced LAT1 activation contributes to the onset of DNP. These findings provide fresh insights into the metabolic differences between DNP and T2DM, and the development of approaches for the management of DNP. [ABSTRACT FROM AUTHOR]

Several studies have linked branched-chain amino acid (BCAA) metabolism disorders with autism spectrum disorder (ASD), but the results have been inconsistent. The purpose of this study was to explore the association between BCAA concentrations and the risk of ASD. A total of 313 participants were recruited from two tertiary referral hospitals from May 2018 to July 2021. Concentrations of BCAAs in dried blood spots were analyzed using liquid chromatography-tandem mass spectrometry-based analysis. Multivariate analyses and restricted cubic spline models were used to identify the association between BCAAs and the risk of ASD, and a nomogram was developed by using multivariate logistic regression and the risk was determined by receiver operating characteristic curve analysis and calibration curve analysis. Concentrations of total BCAA, valine, and leucine/isoleucine were higher in the ASD group, and all of them were positively and non-linearly associated with the risk of ASD even after adjusting for potential confounding factors such as age, gender, body mass index, and concentrations of BCAAs (P < 0.05). The nomogram integrating total BCAA and valine showed a good discriminant AUC value of 0.756 (95% CI 0.676–0.835). The model could yield net benefits across a reasonable range of risk thresholds. In the stratified analysis, the diagnostic ability of the model was more pronounced in children older than 3 years. We provide evidence that increased levels of BCAAs are associated with the risk of ASD, and the nomogram model of BCAAs presented here can serve as a marker for the early diagnosis of ASD. [ABSTRACT FROM AUTHOR]

Introduction: During aging, sarcopenia and decline in physiological processes lead to partial loss of muscle strength, atrophy, and increased fatigability. Muscle changes may be related to a reduced intake of essential amino acids playing a role in proteostasis. We have recently shown that branched-chain amino acid (BCAA) supplements improve atrophy and weakness in models of muscle disuse and aging. Considering the key roles that the alteration of Ca2+-related homeostasis and store-operated calcium entry (SOCE) play in several muscle dysfunctions, this study has been aimed at gaining insight into the potential ability of BCAAbased dietary formulations in aged mice on various players of Ca2+ dyshomeostasis. Methods: Seventeen-month-old male C57BL/6J mice received a 12-week supplementation with BCAAs alone or boosted with two equivalents of L-alanine (2-Ala) or with dipeptide L-alanyl-L-alanine (Di-Ala) in drinking water. Outcomes were evaluated on ex vivo skeletal muscles indices vs. adult 3-month-old male C57BL/6J mice. Results: Ca2+ imaging confirmed a decrease in SOCE and an increase of resting Ca2+ concentration in aged vs. adult mice without alteration in the canonical components of SOCE. Aged muscles vs. adult muscles were characterized by a decrease in the expression of ryanodine receptor 1 (RyR1), the SarcoEndoplasmic Reticulum Calcium ATPase (SERCA) pump, and sarcalumenin together with an alteration of the expression of mitsugumin 29 and mitsugumin 53, two recently recognized players in the SOCE mechanism. BCAAs, particularly the formulation BCAAs+2-Ala, were able to ameliorate all these alterations. Discussion: These results provide evidence that Ca2+ homeostasis dysfunction plays a role in the functional deficit observed in aged muscle and supports the interest of dietary BCAA supplementation in counteracting sarcopenia-related SOCE dysregulation. [ABSTRACT FROM AUTHOR]

l -Valine, l -isoleucine, and l -leucine are three key proteinogenic amino acids, and they are also the essential amino acids required for mammalian growth, possessing important and to some extent, special physiological and biological functions. Because of the branched structures in their carbon chains, they are also named as branched-chain amino acids (BCAAs). This review will highlight the advance in studies of the enzymes involved in the biosynthetic pathway of BCAAs, concentrating on their chemical mechanisms and applications in screening herbicides and antibacterial agents. The uses of some of these enzymes in lab scale organic synthesis are also discussed. The enzymes involved in the biosynthetic pathway of the branched-chain amino acids are reviewed in this paper, focusing on their chemical mechanisms and applications. [Display omitted] • Enzymes involved in the biosynthetic pathway of BCAAs are reviewed. • Chemical mechanisms of these enzymes are discussed. • Applications of the enzymes in screening herbicides and antibacterials are involved. • Utilization of parts of these enzymes in organic synthesis are included. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD), also known as metabolically associated fatty liver disease (MAFLD), is a systemic metabolic disease characterized by lipid accumulation in the liver, lipid toxicity, insulin resistance, intestinal dysbiosis, and inflammation that can progress from simple steatosis to nonalcoholic steatohepatitis (NASH) and even cirrhosis or cancer. It is the most prevalent illness threatening world health. Currently, there are almost no approved drug interventions for MAFLD, mainly dietary changes and exercise to control weight and regulate metabolic disorders. Meanwhile, the metabolic pathway involved in amino acid metabolism also influences the onset and development of MAFLD in the body, and most amino acid metabolism takes place in the liver. Essential amino acids are those amino acids that must be supplemented from outside the diet and that cannot be synthesized in the body or cannot be synthesized at a rate sufficient to meet the body's needs, including leucine, isoleucine, valine (collectively known as branched-chain amino acids), tryptophan, phenylalanine (which are aromatic amino acids), histidine, methionine, threonine and lysine. The metabolic balance of the body is closely linked to these essential amino acids, and essential amino acids are closely linked to the pathophysiological process of MAFLD. In this paper, we will focus on the metabolism of essential amino acids in the body and further explore the therapeutic strategies for MAFLD based on the studies conducted in recent years. [ABSTRACT FROM AUTHOR]

Prevention/management of cachexia remains a critical issue in muscle wasting conditions. The branched-chain amino acids (BCAA) have anabolic properties in skeletal muscle, but their use in treating cachexia has minimal benefits. This may be related to altered BCAA metabolism consequent to the use of chemotherapy, a main cancer treatment. Since this topic is minimally studied, we investigated the effect of chemotherapy on BCAA concentrations, transporter expression, and their metabolism. L6 myotubes were treated with vehicle (1.4 μL/mL DMSO) or a chemotherapy drug cocktail, FOLFIRI [CPT-11 (20 μg/mL), leucovorin (10 μg/mL), and 5-fluorouracil (50 μg/mL)] for 24-48 h. Chemotherapy reduced myotube diameter (~43%), myofibrillar protein content (~50%), and phosphorylation of the mechanistic target of rapamycin complex 1 (mTORC1) substrate S6K1thr389 (~80%). Drugtreated myotubes exhibited decreased BCAA concentrations (~52%) and expression of their transporter, L-type amino acid transporter 1 (LAT1; ~67%). BCAA transaminase BCAT2 level was increased, but there was a reduction in PP2CM (~54%), along with increased inhibitory phosphorylation of BCKD-E1aser293 (þ98%), corresponding with decreased BCKD enzyme activity (~23%) in chemotherapy-treated myotubes. Decreases in BCAA concentrations were a later response, preceded by decreases in LAT1 and BCKD activity. Although supplementation with the BCAA restored myotube BCAA levels, it had minimal effects on preventing the loss of myofibrillar proteins. However, RNAi-mediated depletion of neural precursor cell-expressed developmentally downregulated gene 4 (NEdd4), the protein ligase responsible for ubiquitin-dependent degradation of LAT1, attenuated the effects of chemotherapy on BCAA concentrations, anabolic signaling, protein synthesis, and myofibrillar protein abundance. Thus, if our findings are validated in preclinical models, interventions regulating muscle amino acid transporters might represent a promising strategy to treat cachexia. [ABSTRACT FROM AUTHOR]

The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30–35 kg) were prepared with arterial catheters. After recovery, they received for 7 d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16 h postabsorptive) and after the morning meal (4 h postprandial). The animals were then divided into three groups and received for a further 7 d a methionine-limiting diet (80 % of requirement) (1) without any amino acid excess; (2) with excess leucine (50 % over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50 % over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0·05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0·05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0·05) increased by excesses of leucine or all BCAA. [ABSTRACT FROM PUBLISHER]

In recent decades, following the spread of obesity, metabolic dysfunction has come to represent the leading cause of liver disease. The classical clinical presentation of the cirrhotic patient has, therefore, greatly changed, with a dramatic increase in subjects who appear overweight or obese. Due to an obesogenic lifestyle (lack of physical activity and overall malnutrition, with an excess of caloric intake together with a deficit of proteins and micronutrients), these patients frequently develop a complex clinical condition defined as sarcopenic obesity (SO). The interplay between cirrhosis and SO lies in the sharing of multiple pathogenetic mechanisms, including malnutrition/malabsorption, chronic inflammation, hyperammonemia and insulin resistance. The presence of SO worsens the outcome of cirrhotic patients, affecting overall morbidity and mortality. International nutrition and liver diseases societies strongly agree on recommending the use of food as an integral part of the healing process in the comprehensive management of these patients, including a reduction in caloric intake, protein and micronutrient supplementation and sodium restriction. Based on the pathophysiological paths shared by cirrhosis and SO, this narrative review aims to highlight the nutritional interventions currently advocated by international guidelines, as well as to provide hints on the possible role of micronutrients and nutraceuticals in the treatment of this multifaceted clinical condition. [ABSTRACT FROM AUTHOR]

This paper presents the first purification of the mitochondrial branched‐chain amino acid aminotransferase (BCATm) from sheep placenta. It is a homodimer with an apparent subunit molecular mass of 41 kDa. The enzyme differs from those of the rat and human as it appears to form at least one intermolecular disulfide bond. The sheep BCATm cDNA (1.4 kb) encodes a mature polypeptide of 366 amino acids with a calculated molecular mass of 41 329 Da and a partial mitochondrial targeting sequence of seven amino acids. The sheep BCATm sequence shares higher identity with other mammalian BCATm isoenzymes (82–85%) than with the cytosolic isoenzymes (60%). By Northern blot analysis, a message of 1.7 kb was detected in sheep placenta and skeletal muscle. Measurements of BCAT activity, mRNA and BCATm protein in sheep placenta and skeletal muscle revealed that BCATm is the sole BCAT isoenzyme expressed in placenta, whereas it contributes 57 and 71% of the BCAT activity in tensor fascia latae and masseter muscles from weaned lambs respectively. Skeletal muscle, the main site of branched‐chain amino acid transamination, exhibits significantly lower BCAT activity in sheep than in rat. Our results suggest that the low BCATm mRNA level probably accounts for the low BCAT activity in sheep skeletal muscle, and that the metabolic scheme for branched‐chain amino acid catabolism is specific to each species. [ABSTRACT FROM AUTHOR]