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PubMed2006

Effect of chronic supplementation with branched-chain amino acids on the performance and hepatic and muscle glycogen content in trained rats.

The objective of this study was to evaluate the effects of a diet supplemented with branched-chain amino acids (BCAA; 3.57% and 4.76%) on the performance and glycogen metabolism of trained rats. Thirty-six adult male Wistar rats received the control diet (AIN-93M) (n=12) and two diets supplemented with BCAA (S1: AIN-93M+3.57% BCAA, n=12, and S2: AIN-93M+4.76% BCAA, n=12) for 6 weeks. The training protocol consisted of bouts of swimming exercise (60 min day(-1)) for 6 weeks at intensities close to the lactate threshold. On the last day of the experiment, all groups were trained for 1 h (1H) or were submitted to the exhaustion test (EX). The time to exhaustion did not differ between groups. The groups submitted to the exhaustion test presented a reduction in plasma glucose and an increase in plasma ammonia and blood lactate concentrations compared to the 1H condition. In the 1H condition, hepatic glycogen concentration was significantly higher in group S2 compared to the control diet and S1 groups (132% and 44%, respectively). Group S2 in the 1H condition presented a higher muscle glycogen concentration (45%) compared to the control diet group. In the EX condition, a significantly higher hepatic glycogen concentration was observed for group S2 compared to the control diet and S1 groups (262% and 222%, respectively). Chronic supplementation with BCAA promoted a higher hepatic and muscle glycogen concentration in trained animals, with this effect being dose dependent.

Amino Acids, Branched-Chain↗
PubMed1997

The effects of dieting on plasma tryptophan concentration and food intake in healthy women.

Although many people diet, relatively few dieters are successful in maintaining weight loss. The extent to which dieting behavior might dampen satiety responses normally mediated by the neurotransmitter serotonin remains uncertain. This study tested the hypothesis that dieting behavior decreases the availability of plasma tryptophan (TRP) and the ratio of TRP to other branched-chain amino acids (BCAA) that compete for entry into the central nervous system (CNS). This effect could diminish the CNS concentration of TRP, the amino acid precursor for serotonin synthesis, thus interfering with serotonin-mediated influences on food intake. Using a fixed-order design, 15 healthy, normal-weight women were studied longitudinally during an ad lib dietary intake phase and subsequent reduced-calorie diet phase. Physiological and behavioral measures were collected at baseline, at the end of the ad lib-intake phase, and at the end of the 4-week study diet phase. Food intake was measured by a single-item test meal. Plasma TRP and TRP: sigma BCAA significantly decreased following the study diet compared to baseline (p < 0.05). Change in TRP and TRP: sigma BCAA significantly correlated with decrease in body weight (p < 0.01). No significant relationship was observed between postdiet change in TRP or TRP: sigma BCAA ratio and postdiet change in test meal food intake, with covariation for weight loss. The observed decreases in plasma TRP and TRP: sigma BCAA extend previous reports suggesting that dieting behavior may diminish central serotonin function through a reduction in precursor availability.

Adult↗
PubMed2000

Serotonergic markers and lowered plasma branched-chain-amino acid concentrations in fibromyalgia.

The aims of the present study were to examine serotonergic markers, i.e. [3H]paroxetine binding characteristics and the availability of plasma tryptophan, the precursor of serotonin (5-HT), and the plasma concentrations of the branched chain amino acids (BCAAs), valine, leucine and isoleucine, in fibromyalgia. The [3H]paroxetine binding characteristics, B(max) and K(d) values, and tryptophan and the competing amino acids (CAA), known to compete for the same cerebral uptake mechanism (i.e. valine, leucine, isoleucine, phenylalanine and tyrosine), were determined in fibromyalgia patients and normal controls. There were no significant differences in the [3H]paroxetine binding characteristics (B(max) and K(d)) between fibromyalgia and control subjects. There were no significant differences in plasma tryptophan or the tryptophan/CAA ratio between fibromyalgia patients and normal controls. In the fibromyalgia patients, there were no significant correlations between [3H]paroxetine binding characteristics or the availability of tryptophan and myalgic or depressive symptoms. Patients with fibromyalgia had significantly lower plasma concentrations of the three BCAAs (valine, leucine and isoleucine) and phenylalanine than normal controls. It is hypothesized that the relative deficiency in the BCAAs may play a role in the pathophysiology of fibromyalgia, since the BCAAs supply energy to the muscle and regulate protein synthesis in the muscles. A supplemental trial with BCAAs in fibromyalgia appears to be justified.

Adult↗
PubMed1996

Hyperammonemia-induced depletion of glutamate and branched-chain amino acids in muscle and plasma.

BACKGROUND/AIMS: Exogenous hyperammonemia is known to decrease the plasma levels of branched-chain amino acids (BCAA). To investigate whether changes in intracellular amino acid concentrations of muscle are associated with and may, at least in part, mediate this effect, experiments were carried out on a total of 60 male Wistar rats. METHODS: Five groups were formed in a randomized manner. Group A: no treatment; groups B1 and B2: 2-hour and 6-hour continuous central-venous infusions, respectively, of sodium salts; groups C1 and C2: 2-hour and 6-hour infusions of ammonium salts. We obtained venous blood samples and muscle biopsies. Plasma ammonia, whole blood glucose, serum insulin, blood pH, and amino acids in plasma as well as in the intracellular water of muscle were measured. RESULTS: As compared with control group A, groups C1 and C2 displayed a 3.3- and a 4-fold increase, respectively, in the plasma ammonium concentration. Regarding insulin, the ammonium-infused rats were similar to group A but not to the sodium-infused B groups, which had significantly lower insulin concentrations. Administering ammonium brought about a decline in BCAA concentrations in plasma after 2 hours and in muscle after 6 hours. The ammonium-induced fall in intracellular BCAA values was preceded by an increase of glutamine as well as by a decrease of glutamate and alanine in both plasma and muscle. CONCLUSIONS: It is pointed out that the inter-group differences in serum insulin, although possibly accounting for some of the findings, can by no means explain the entire pattern of amino acid concentrations seen after the ammonium infusions. Instead, our results agree with the hypothesis that hyperammonemia indirectly lowers the plasma levels of BCAA by stimulating glutamine synthesis, thus reducing the intracellular glutamate pool, which is likely to be restored, at least in part, by an intensified BCAA transamination. Clarification is needed as to whether carbon skeletons derived from valine and isoleucine additionally contribute to replenishing the glutamate pool.

Alanine↗
PubMed1996

Effects of administration of oral branched-chain amino acids on anorexia and caloric intake in cancer patients.

In this double-blind prospective study, the authors examined the effect of an oral supplement consisting of a branched-chain amino acid (BCAA) mixture or an isonitrogenous placebo on food intake in anorexic cancer patients (n = 28). For all patients, biochemical indices of nutritional status were within the normal range before and after the study. BCAA supplement (3 times 4.8 g/d for 7 consecutive days) increased BCAA concentrations in plasma (+121% on day 7 vs day 0) and decreased the tryptophan/large neutral amino acids (LNAA) ratio by 40%. Meanwhile, incidence of anorexia decreased in the BCAA-treated group (100% prior vs. 45% at the end of the study) but not in the placebo group (84% at the end of the study). The authors conclude that oral BCAA supplement can be safely used in the treatment of cancer-induced anorexia.

Journal Article↗
PubMed1996

Immediately elevated postoperative serum branched-chain amino acids following effective GI decompression and enteral feeding.

Postoperative patients are hypercatabolic. They also suffer a degree of gastrointestinal (GI) dysfunction impairing nutritional intake. Safe enteral absorption had been limited to a maximum of 500 kcal provided over the initial 24 h in all previously reported regimens. Several days of negative nitrogen balance and diminution of serum branched-chain amino acids (BCAA) result. Some data suggest an association with suboptimal wound healing, and immune competence. We tested the hypothesis that immediate exploitation of more effectively preserved GI function could prevent this depressed serum concentration within hours of surgery. Our study group consisted of 34 consecutive elective "open" cholecystectomy patients who had terminal esophageal, gastric, and proximal duodenal decompression. Simultaneous distal duodenal feeding of elemental diet began immediately in the Recovery Room at 300 mL/h for 8-16 h, providing 2,400-4,800 kcal and 100-200 g amino acids. We found that each serum BCAA concentration rose above basal by one hour. The differences reached statistical significance (p < or = 0.05) within 2 h after surgery, when leucine had risen above basal levels by 70%, isoleucine by 63%, and valine by 26%. Elevations in these BCAA serum concentrations persisted for the duration of feeding. GI function can be maintained and successfully utilized in the immediate postoperative period for absorption of 300 kcal/h. Postoperative depression of serum BCAA concentrations are prevented. The serum BCAA rise of these GI protected and immediately fed postoperative patients contrasts with the 48-72 h decline universally reported with conventional protein- and calorie-deficient regimens. The optimum nutritional regimen for achievement of clinically significant enhanced wound healing, sepsis resistance, and muscle sparing, remains to be determined.

Adult↗
PubMed1996

The effect of branched-chain amino acid-enriched parenteral nutrition on gut permeability.

In situations of catabolic stress, the gut becomes atrophic and has a diminished barrier function as evidenced by an increased permeability to a variety of molecules. It is known that the parenteral administration of branched-chain amino acids (BCAA) reduce gut atrophy. The aim of this study was to examine the effect of BCAA-enriched solutions of parenteral nutrients on gut permeability. A secondary aim was to observe the association between gut permeability and variables that have been used to assess jejunal atrophy. Central venous lines were inserted into 30 rats before randomization to receive nutritional support with: (1) a conventional parenteral solution (CPN), (2) A 2.0% BCAA-enriched solution (BCAA), or (3) rat food ad lib (Rat Food). The rats were assessed after 7 d for nutritional status, gut morphology, and gut permeability ratio (ratio of the permeability to 14C raffinose and 3H mannitol). We found that rats in the Rat Food Group lost the least amount of weight, had the least amount of jejunal atrophy, and had better preservation of barrier function as determined by gut permeability. When compared with the CPN Group, the BCAA Group had better preservation of jejunal morphology and protein content (p < 0.05), but a similar gut permeability. A cross-correlation matrix demonstrated a significant negative correlation between permeability to mannitol and mucosal weight, mucosal protein content and mucosal DNA content. Branched-chain amino acid-enriched parenteral nutrition reduced gut atrophy but not the gut permeability associated with parenteral nutrition. In the parenterally nourished rat model, atrophy of the jejunum is associated with increased permeability to small molecules.

Amino Acids, Branched-Chain↗
PubMed1999

Attenuation of the protein wasting associated with bed rest by branched-chain amino acids.

Bed rest is generally accepted as being an appropriate ground-based model for human spaceflight. The objectives of this study were to test the hypothesis that increasing the amount of branched-chain amino acids (BCAAs) in the diet could attenuate the protein loss associated with bed rest. Nineteen healthy subjects were randomized into two groups according to diet. During the 6 d of bed rest, the diets were supplemented with either 30 mmol/d each of three non-essential amino acids, glycine, serine, and alanine (control group), or with 30 mmol/d each of the BCAAs, leucine, isoleucine, and valine (BCAA group). Nutrition was supplied as a commercially available defined formula diet at a rate of 1.3 x REE. Nitrogen (N) balance and urinary 3-MeH excretion were determined for the 6 d. In our results, the urine-based estimate of N balance was 22.2 +/- 14.4 (n = 9) mg N.kg-1.d-1 and 60.5 +/- 10.1 mg (n = 8) N.kg-1.d-1 for the control and BCAA-supplemented groups, respectively (P < 0.05). Urinary 3-MeH excretion was unchanged in both groups with bed rest. We conclude that BCAA supplementation attenuates the N loss during short-term bed rest.

Adult↗
PubMed2003

Effect of oral supplementation with branched-chain amino acid granules on serum albumin level in the early stage of cirrhosis: a randomized pilot trial.

We designed a randomized pilot trial to examine whether increase or preservation of serum albumin levels was attained with earlier administration of branched-chain amino acid (BCAA) granules for cirrhosis in grade A according to Child-Pugh classification using branched-chain tyrosine ratio (BTR) as an indicator. Forty patients with HCV-related cirrhosis in grade A with serum albumin level between 3.5 and 3.9 g/dl were enrolled in this study. Half of the patients were randomly assigned to receive 14.3 g/day of BCAA granules orally, and half were assigned to a control. Patients were evaluated at entry and at 1-year interval for at least 2 years. For patients whose BTR was less than 4.0, mean change in serum albumin in the BCAA group was significantly higher than that in the control group after 1 and 2 years of treatment. However, for patients whose BTR was more than 4.0, mean change in serum albumin in the BCAA group was not significantly higher than that in the control group after 1 and 2 years of treatment. In conclusion, early oral supplementation of BCAA for HCV-related cirrhosis with serum albumin level between 3.5 and 3.9 g/dl and BTR less than 4.0, improves serum albumin levels and thus might improve prognosis.

Journal Article↗
PubMed2003

Beneficial effects of branched-chain amino acids on altered protein and amino acid metabolism in liver cirrhosis: evaluation in a model of liver cirrhosis induced in rats with carbon tetrachloride.

The effect of branched-chain amino acids (BCAA) on the metabolism of protein, amino acids and ammonia was examined in rats with cirrhosis, with a special emphasis on the efficacy of early administration of BCAA. Liver cirrhosis was induced in rats by intraperitoneal injections of carbon tetrachloride (CCl(4)). The rats were divided into three groups: early-, late- and untreated. The early- and late-treated groups were given BCAA rich food from the early and late stage of liver cirrhosis, while the untreated group was given standard food throughout. Concentrations of amino acids and ammonia in the plasma and the ornithine carbamyl transferase (OCT) activity in the liver were evaluated, and compared with control group after 15 weeks maintenance. Ammonia was significantly higher in the late- and untreated groups, but not in the early-treated group. BCAA, tyrosine, and methionine were significantly lower in the untreated and late-treated groups. Glutamine increased significantly in the un-, late- and early-treated groups. However, no significant differences were found among three groups. A significant difference was found in 3-methyl histidine (3-MH) between the early- and late-treated groups. This study suggests that the administration of BCAA from early stage of liver cirrhosis inhibits breakdown of protein and improves metabolism of protein, amino acids and ammonia.

Journal Article↗
PubMed2003

Amino acid ratios in plasma and tissues in a rat model of liver cirrhosis before and after exercise.

In human liver cirrhosis (LC), the Fischer ratio (branched-chain amino acid (BCAA)/aromatic amino acid (AAA)) is used as a marker of hepatic encephalopathy. Similarly, the plasma BCAA levels decrease while AAA levels increase in LC rats. However the BCAA and AAA ratio and the influence of exercise on this ratio remains to be clarified in various tissues of the LC rat model. Normal and LC rats received 2-weekly injections of olive oil or CCl(4) for 10 weeks, respectively, and half of the rats from each group were subjected to one time exercise on a treadmill. BCAA, AAA, glutamate (GLU) and glutamine (GLN) concentrations were measured in plasma, liver, brain, heart and skeletal muscles. Decreased BCAA and increased AAA concentrations in brain and heart were also observed in LC rats and these changes were significantly amplified by exercise. The Fischer ratio in the LC group with and without exercise was decreased in skeletal muscles, while it remained unchanged in the liver. Decreased GLU and increased GLN concentrations were shown in most LC samples following exercise. In conclusion, specific alterations of the amino acid patterns were observed in various tissues in the LC group. These alterations were further emphasized by exercise.

Journal Article↗
PubMed2006

Impaired growth and neurological abnormalities in branched-chain alpha-keto acid dehydrogenase kinase-deficient mice.

The BCKDH (branched-chain alpha-keto acid dehydrogenase complex) catalyses the rate-limiting step in the oxidation of BCAAs (branched-chain amino acids). Activity of the complex is regulated by a specific kinase, BDK (BCKDH kinase), which causes inactivation, and a phosphatase, BDP (BCKDH phosphatase), which causes activation. In the present study, the effect of the disruption of the BDK gene on growth and development of mice was investigated. BCKDH activity was much greater in most tissues of BDK-/- mice. This occurred in part because the E1 component of the complex cannot be phosphorylated due to the absence of BDK and also because greater than normal amounts of the E1 component were present in tissues of BDK-/- mice. Lack of control of BCKDH activity resulted in markedly lower blood and tissue levels of the BCAAs in BDK-/- mice. At 12 weeks of age, BDK-/- mice were 15% smaller than wild-type mice and their fur lacked normal lustre. Brain, muscle and adipose tissue weights were reduced, whereas weights of the liver and kidney were greater. Neurological abnormalities were apparent by hind limb flexion throughout life and epileptic seizures after 6-7 months of age. Inhibition of protein synthesis in the brain due to hyperphosphorylation of eIF2alpha (eukaryotic translation initiation factor 2alpha) might contribute to the neurological abnormalities seen in BDK-/- mice. BDK-/- mice show significant improvement in growth and appearance when fed a high protein diet, suggesting that higher amounts of dietary BCAA can partially compensate for increased oxidation in BDK-/- mice. Disruption of the BDK gene establishes that regulation of BCKDH by phosphorylation is critically important for the regulation of oxidative disposal of BCAAs. The phenotype of the BDK-/- mice demonstrates the importance of tight regulation of oxidative disposal of BCAAs for normal growth and neurological function.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1998

The altered plasma amino acid pattern is responsible for the paradoxical growth hormone response to the oral glucose tolerance test in liver cirrhosis.

OBJECTIVE: An increased basal growth hormone (GH) secretion and a parodoxical GH response to the oral glucose tolerance test (OGTT) have been reported in patients with liver cirrhosis. It has been suggested that the ratio between branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) (BCAA/ AAA ratio) may determine in part the brain concentration of the AAAs, since the BCAAs compete with the AAAs for entry across the blood-brain barrier, leading to the accumulation of false neurotransmitters such as octopamine and phenylethanolamine, which are able to stimulate GH secretion (via alpha 2-adrenergic stimulation). In this study we investigated the role of amino acids, particularly the BCAA/AAA ratio, in the paradoxical response of GH to the OGTT in patients with liver cirrhosis. PATIENTS AND DESIGN: Twelve non-diabetic patients with biopsy-proven cirrhosis of the liver underwent an OGTT. Three of the five patients with a paradoxical response of GH to the OGTT underwent a second oral glucose administration associated with an infusion of BCAA solution from -30 min until 180 min. RESULTS: During the OGTT, glucose and insulin levels increased from 4.8 +/- 0.2 to 9.6 +/- 0.7 mmol/l (P < 0.001) and from 18.8 +/- 2.6 to 104.4 +/- 13.8 mU/l (P < 0.005), respectively. GH levels increased from 8.6 +/- 2.6 to 22.4 +/- 10.8 mU/l although not significantly. Five patients had a paradoxical GH response to the OGTT. A negative correlation between serum GH values and BCAA/AAA ratio in the plasma at every time point of the OGTT was found. After co-administration of glucose and BCAA in three patients the BCAA/AAAs ratio increased, abolishing the paradoxical GH secretion. CONCLUSIONS: Our data suggest that in liver cirrhosis the altered BCAA/AAA ratio may influence the altered basal GH secretion and the paradoxical GH response to the OGTT, probably by an increase of adrenergic mediators in the brain. Moreover, the increase of BCAA/AAA ratio seems to be able to abolish the GH paradoxical response to the OGTT.

Adult↗
PubMed2001

Pleiotropic transcriptional repressor CodY senses the intracellular pool of branched-chain amino acids in Lactococcus lactis.

Proteolysis is essential for supplying Lactococcus lactis with amino acids during growth in milk. Expression of the major components of the L. lactis proteolytic system, including the cell wall proteinase (PrtP), the oligopeptide transport system (Opp) and at least four intracellular peptidases (PepO1, PepN, PepC, PepDA2), was shown previously to be controlled negatively by a rich nitrogen source. The transcription of prtP, opp-pepO1, pepN and pepC genes is regulated by dipeptides in the medium. Random insertion mutants derepressed for nitrogen control in the expression of the oligopeptide transport system were isolated using an opp-lacZ fusion. A third of the mutants were targeted in the same locus. The product of the inactivated gene shared 48% identity with CodY from Bacillus subtilis, a pleiotropic repressor of the dipeptide permease operon (dpp) and several genes including genes involved in amino acid degradation and competence induction. The signal controlling CodY-dependent repression was searched for by analysing the response of the opp-lux fusion to the addition of 67 dipeptides with different amino acid compositions. Full correlation was found between the dipeptide content in branched-chain amino acids (BCAA; isoleucine, leucine or valine) and their ability to mediate the repression of opp-pepO1 expression. The repressive effect resulting from specific regulatory dipeptides was abolished in L. lactis mutants affected in terms of their transport or degradation into amino acids, showing that the signal was dependent on the BCAA pool in the cell. Lastly, the repression of opp-pepO1 expression was stronger in a mutant unable to degrade BCAAs, underlining the central role of BCAAs as a signal for CodY activity. This pattern of regulation suggests that, in L. lactis and possibly other Gram-positive bacteria, CodY is a pleiotropic repressor sensing nutritional supply as a function of the BCAA pool in the cell.

ATP-Binding Cassette Transporters↗
PubMed2000

Effect of branched-chain amino acids on the composition and cytolytic activity of liver-associated lymphocytes in rats.

BACKGROUND: Although branched-chain aminoacids (BCAA) are reported to be effective in prolongation of the mean survival time of patients with liver cirrhosis, it is not clear whether BCAA could influence the immune function in those patients. METHODS: Branched-chain amino acids were given as a supplement to carbon tetrachloride-induced cirrhotic rats, and an aminogram of the liver and kinetics of liver-associated lymphocytes (LAL) were then analysed. RESULTS: Liver cirrhosis was established at the 12th week, and glutathione S-transferase placental form (GST-P)-positive lesions, which are known to be pre-neoplastic lesions, occupied 1.72+/-0.84% of the liver at the 16th week in the controls. At this time the LAL showed an increase in the number of CD5-, CD8- and CD18-positive cells and augmentation of lectin-dependent cellular cytotoxicity (LDCC) activity. Furthermore, supplementation of BCAA increased the number of LAL, especially CD8-positive cells and natural killer cells, and augmented LDCC activity of LAL at the 16th week. The number of LAL was positively correlated with the valine concentration in the plasma and liver, and the area of GST-P-positive lesions tended to be decreased in the BCAA group. CONCLUSION: These findings suggest that BCAA administration has stimulatory effects on the local immune systems of the liver, which may have a potential to inhibit hepatocarcinogenesis. Moreover, among all amino acids valine might be an important amino acid for enhancing the immune function of LAL.

Amino Acids, Branched-Chain↗
PubMed1996

Neuronal metabolism of branched-chain amino acids: flux through the aminotransferase pathway in synaptosomes.

The metabolism of branched-chain amino acids (BCAAs) was studied in cortical synaptosomes. With [15N]leucine (1 mM) as precursor, the cumulative appearance of 15N in [15N]glutamate and [15N]aspartate was 0.2 nmol/min/mg of protein without supplemental alpha-ketoglutarate and 0.3 nmol/min/mg of protein in the presence of alpha-ketoglutarate (0.5 mM). The BCAA amino-transferase reaction also proceeded in the "reverse" direction [alpha-ketoisocaproate (KIC) + glutamate-->leucine + alpha-ketoglutarate]. This was documented by incubating synaptosomes with [15N]glutamate and measuring the formation of [15N]leucine. Without KIC in the medium, the rate of [15N]leucine production was 0.13 nmol/min/mg of protein. In the presence of 25 microM KIC the rate was 0.79 nmol/min/mg of protein and even greater (1.0 nmol/ min/mg of protein) in the presence of 500 microM KIC. The reamination of KIC was two- to threefold faster with [2-15N]glutamine as precursor compared with [15N]-glutamate. The ketoacid of valine, alpha-ketoisovalerate (KIV), was reaminated to [15N]valine at a rate comparable to that observed with respect to KIC. The BCAA transaminase mediated not only the bidrectional transfer of amino groups between leucine or valine and glutamate, but also the direct transfer of nitrogen between leucine and valine. This was ascertained in studies in which the incubation medium was supplemented with either [15N]leucine and KIV or [15N]valine and KIC (amino acids at 1 mM and ketoacids at 25 or 500 microM). The rate was faster in the direction of leucine formation at both the lower (6.1-fold) and higher (1.7-fold) KIC concentration. It is suggested that in synaptosomes the BCAA transaminase (a) functions predominantly in the direction of leucine formation and (b) maintains a constant ratio of BCAAs and ketoacids to one other.

Amino Acids, Branched-Chain↗
PubMed1996

Effect of a 6-week endurance training programme and branched-chain amino acid supplementation on histomorphometric characteristics of aged human muscle.

The effects of a 6-week endurance training programme and a branched-chain amino acid (BCAA) supplementation were investigated on skeletal muscle histomorphometric characteristics of elderly men. Seventeen elderly men, age (63 +/- 5 years), height (173 +/- 5 cm) and weight (75 +/- 8 kg) were included in the study. One group (n = 9) received an oral BCAA supplementation for 6 weeks (16, 2 and 2 g per day of leucine, isoleucine and valine, respectively), while another group (n = 8) received a placebo. During these 6 weeks, subjects trained on a Monark cycle ergometer at 75 +/- 9% of their maximal heart rate for 1 h/day, 4 days/week. Muscle biopsy samples taken at rest before and after endurance training were analyzed for capillarization, fibre type distribution and fibre area. As a result of endurance training, maximal oxygen uptake was significantly increased by about 5% in control and BCAA supplemented groups (P < 0.01). The number of capillaries per fibre and in contact with type I fibres was significantly increased (P < 0.05), this effect being similar in control and BCAA supplemented groups. The percentage distribution and area of type I, type IIa and type IIb fibres did not differ between the two groups and remained unchanged with endurance training. It is concluded that skeletal muscle of elderly men can adapt to a 6-week endurance training programme and that a BCAA supplementation does not further enhance the induced histomorphometric changes.

Aged↗
PubMed1992

Brief communication: clinical experience with high branched-chain parenteral nutrition.

Patients who appear to respond best to high branched-chain amino acid (BCAA) solutions have been previously described by objective measurements such as total urinary nitrogen (TUN) excretion, oxygen consumption index (O2Cl), plasma lactate, plasma pyruvate, plasma glucose (PG) and urinary 3-methylhistidine. Use of these measurements in assessing possible candidates for high BCAA solutions may not be convenient for some institutions. The purpose of this study is to describe our clinical practice experience with patients receiving high BCAA parenteral nutrition (PN) and how we apply the criteria previously developed. Forty critically ill adult patients (19 males, 21 females; 50 +/- 19 years) who received BCAA-enriched PN were prospectively monitored for demographic information as well as objective biochemical measurements and current clinical status within a time window of 72 hours before or after beginning the high BCAA solution. Patients demonstrated marked elevations in O2Cl (168 +/- 44 ml/min/m2), TUN (18 +/- 6 g/day), and PG (157 +/- 63 mg/dl), and decreased serum albumin (2.4 +/- 0.6 g/dl) and transferrin (123 +/- 50 mg/dl). Patients were categorized according to primary diagnosis: malignant tumor (n = 10), organ transplant (n = 12), trauma (n = 1), chronic or acute disease (n = 1, n = 3), and chronic or acute disease requiring surgery (n = 7, n = 6). Clinical statuses within the 72-hour time window were as follows: infection (n = 26), renal dysfunction (n = 15), pulmonary dysfunction (n = 22), liver dysfunction (n = 14), and multiple organ failures (n = 14).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗