Effect Of Amino Acid Administration Research Articles

Protective effects of L‐cysteine against LPS‐induced liver injuries.

An activation of Kupffer cells (hepatic resident macrophages) and hepatic stellate cells (HSCs) plays an important role in lipopolysaccharide (LPS)‐induced liver injury. It is known that the upregulated production of ET‐1 by Kupffer cells in response to LPS stress activates HSCs and induces subsequent pathophysiological change in the liver. Recently, it has been reported that some amino acids exhibit anti‐inflammatory effects. In a preliminary experiment, using 20 amino acids, we investigated the effect of amino acid administration on ET‐1 production in the mouse macrophage cell lines (RAW 264.7). Among the amino acids, L‐cysteine, L‐glutamine, L‐leucine, L‐alanine, and Glycine suppressed LPS‐induced ET‐1 production in a dose‐dependent fashion. The effect was strongest by an administration of L‐cysteine. L‐cysteine also suppressed a ET‐1‐induced contraction of collagen gel lattices cultured with HSCs. Moreover, an increased [Ca2+]i in response to ET‐1 administration in HSCs measured with the fluorescent dye fura‐2 was strongly attenuated with the presence of L‐cysteine in a culture medium. In an in vivo experiment, Wister rats were pre‐treated with L‐cysteine or saline and received intravenous injection of LPS. Increased levels of liver function tests following LPS was attenuated by L‐cysteine treatment. These results indicated that L‐cysteine may lead to a beneficial effect in LPS‐induced liver injury.

Evaluation of the Effect of Amino Acid Administration on Hypothermia during General Anesthesia in Hypospadias Surgery on Children Aged 2 to 6 Years

Background: Hypothermia is an important complication during surgery, especially in children and is highly associated with serious adverse outcomes. One of the preventive methods is the intraoperative administration of amino acids, which can be effective through increasing thermogenesis and stimulating energy consumption. No studies have been conducted in this regard on children; therefore, we evaluated the preventive effect of intraoperative administration of amino acid on hypothermia in children. Methods: Forty children, aged 2 to 6 years, who were candidates for hypospadias surgery, were divided into two groups. In the case group, 10% amino acid (2 cc/kg/h) was administered two hours before the operation, and in the control group, normal saline was given as required. All patients underwent a similar method of anesthesia. body temperature was recorded before the anesthesia, immediately after it, and every ten minutes. Results: The mean age and weight had no difference between the groups. Duration of patients' awakening time was 13.60 ± 4.91 min, which in the case and control groups was reported as 11.90 ± 5.27 and 15.30 ± 3.96 min, respectively(p

Glutathione synthesis rates after amino acid administration directly after birth in preterm infants

BackgroundThe availability of glutathione, the main intracellular antioxidant, is compromised in preterm neonates. A possible explanation is the low availability of substrate for synthesis, because many neonatologists are reluctant to administer amino acids in the direct postnatal period for fear of intolerance. ObjectiveThe objective of the study was to determine the effects of amino acid administration directly after birth on glutathione synthesis rates and markers of oxidative stress. DesignPremature infants (<1500 g) received from birth onward either dextrose (control group; n = 10) or dextrose plus 2.4 g amino acids · kg − 1 · d−1 (intervention group; n = 10). On postnatal day 2, [1-13C]glycine was administered to determine glutathione fractional synthesis rates (FSRGSH) and absolute synthesis rates (ASRGSH) in erythrocytes. In plasma, advanced oxidized protein products and dityrosine, both markers of oxidative stress, were measured. The results are expressed as means ± SDs. ResultsThe FSRGSH was not different between groups: 44 ± 6 and 48 ± 9%/d in the control and intervention groups, respectively (P = 0.28). The concentration of erythrocyte glutathione was higher (P < 0.001) in the intervention group (2.28 ± 0.35 mmol/L) than in the control group (1.73 ± 0.37 mmol/L). ASRGSH values were 6.5 ± 1.5 and 11.3 ± 1.9 mg · kg−1 · d−1 in the control and intervention groups, respectively (P < 0.001). Advanced oxidized protein products and dityrosine concentrations were not significantly different between groups. ConclusionsAmino acid administration directly after birth increases ASRGSH in preterm infants. Our data are consistent, however, with higher glutathione concentrations rather than a higher FSRGSH. Greater availability of glutathione, nevertheless, did not decrease markers of oxidative stress.

Oral Amino Acid Administration Decreases Oxidative Stress and Improves Brachial Reactivity in Elderly Individuals

Atherosclerosis is a major cause of death in elderly individuals. Endothelial dysfunction is recognized as a key early event in atherogenesis. In the present study, we evaluated the possible beneficial effect of amino acid administration on endothelial regulation in elderly subjects. A total of 25 healthy elderly subjects were administered essential amino acids (EAA) for 4 months. Before and after EAA administration, each subject underwent brachial reactivity investigation with and without an intra-arterial infusion of 4 micromol/min of N(G)-monomethyl-l-arginine (L-NMMA), an inhibitor of nitric oxide (NO) synthase. At baseline, age correlated with free plasma insulin growth factor-1 IGF-1 (r = -0.48; P < .01), plasma Trolox equivalent antioxidant capacity (TEAC) (r = -0.40; P < .04), and thiobarbituric acid-reactive substances (TBARS) (r = 0.42, P < .04), and homeostasis model assessment (HOMA) index (r = 0.45, P < .03), as well as with changes in diameter (r = -0.49, P < .01) and flow (r = -0.43, P < .03). Administration of EAA was associated with a significant increase in plasma TEAC (P < .001) and decline in plasma TBARS (P < .001) and with improvement in changes in diameter (7.15 +/-1.10 v 8.98 +/-1.80, P < .001) and flow (5.6 +/-1.2 v 6.4 +/- 1.2, P < .03). These latter two associations were independent of changes in HOMA index (P < .04 for both correlations). The beneficial effects of EAA administration on brachial reactivity were partly attenuated by L-NMMA. Administration of EAA may improve brachial reactivity in elderly persons and may also protect against the development of atherosclerosis via the rise in plasma-free IGF-1 levels.

Effect of amino acid administration on uremic muscle metabolism: A 31P-spectroscopy study

The effect of a six-month peritoneal amino acid administration on muscle metabolism at rest and during exercise was examined in 12 patients (4 control and 8 amino acid treated) on continuous ambulatory peritoneal dialysis. 31P-magnetic resonance spectroscopy was used to measure several high-energy phosphates (PCr, Pi) in resting muscle and during exercise and recovery. At rest, no significant changes were detected between the non-treated (control) and the amino acid treated (experimental) group. Before the administration of amino acids, the exercise-induced fall in [PCr], the increase in [ADP] and [Pi] and the pH were not significantly different in the control and experimental group. The initial rate of PCr recovery and the calculated maximal rate of ATP-synthesis (Qmax) for the control subjects was not significantly different at the onset and the end of the study. In the treated group, however, the fall in [PCr] and increase in [ADP] after exercise were significantly lower after than before treatment, while [Pi] and pH were identical. The initial rate of PCr recovery and Qmax were also significantly improved. These changes indicate an improved oxidative phosphorylation under the treatment and suggest that the impaired oxidative metabolism of the dialysis patients could be the result of their bad nutritional state.

Effects of i.v. amino acids on human splanchnic and whole body oxygen consumption, blood flow, and blood temperatures.

The thermic effect of amino acid administration was examined in healthy subjects. Pulmonary and splanchnic oxygen uptake, cardiac output, splanchnic blood flow, and blood temperatures were measured in eight healthy men before and during 2.5 h of intravenous infusion of 600 kJ of a mixture of 19 amino acids. Indirect calorimetry and catheter techniques were used, including thermometry in arterial and a hepatic venous blood. During the infusion, pulmonary oxygen uptake rose progressively from a basal value of 269 +/- 6 to 321 +/- 8 ml/min after 2.5 h. The splanchnic oxygen consumption increased from a basal level of 64 +/- 4 to a peak value of 91 +/- 7 ml/min after 2 h of infusion. The 2.5 h average splanchnic proportion of the amino acid-induced whole body thermogenesis was 51 +/- 11%. Cardiac output increased from 6.2 +/- 0.3 in the basal state to 7.3 +/- 0.4 l/min, whereas the splanchnic blood flow remained unchanged during the infusion period. The arteriohepatic venous oxygen difference increased from 51 +/- 4 in the basal state to 65 +/- 5 ml/l after 2 h of amino acid infusion. The blood temperature rose by approximately 0.25 degrees C during the amino acid infusion, reflecting an increased heat accumulation in the body. It is concluded that the splanchnic tissues account for approximately one-half of the amino acid-induced whole body thermogenesis, that amino acid infusion augments blood flow in the extrasplanchnic but not in the splanchnic tissues, and stimulates the accumulation of heat in the body most likely via a resetting of the central thermosensors.

Dependency of the O2 consumption/O2 transport relationship on amino acid supply in sepsis

In sepsis tissue O2 uptake may be abnormally limited because of a depressed O2 consumption/O2 transport relationship. This study has been performed to assess patterns of O2 consumption, CO2 production and O2 transport in septic patients undergoing total parenteral nutrition; more in particular, this study has investigated the interdependence between the patterns of blood O2 uptake and simultaneous CO2 release, and the availability of substrates (amino acids, glucose and fat). It has been shown that the O2 consumption/O2 transport relationship is significantly influenced by the exogenous amino acid load, which tends to increase O2 uptake and O2 consumption at any given O2 transport, thus suggesting a favourable effect of amino acid administration on energy metabolism. The data on CO2 production and CO2 release, in addition to reconfirming the results of previous studies, have shown that the changes in O2 uptake and in CO2 production mediated by substrate doses have a quantifiable impact on blood O2-CO2 exchange interactions.

Peripheral tissue energy metabolism during recovery from hypothermia after cardiopulmonary bypass: effect of amino-acid infusions

We studied the effects of amino-acid administration on the leg exchange of energy substrates and amino-acids during recovery from hypothermia after open heart surgery. Glucose (G, n = 5), glucose and conventional amino-acids (CA, n = 5) or glucose and branched chain amino-acids (BC, n = 5) were infused during recovery from hypothermia after open heart surgery. The leg exchange of energy substrates and amino-acids were measured after arrival at the intensive care unit, after rewarming, and 2h and 4h after rewarming during increasing amino-acid intake. Despite a normal stress response to surgery, reflected by increased energy expenditure and increased concentrations of insulin and catabolic hormones, amino-acids had no effect on the leg exchange of branched chain amino-acids, glutamine, alanine and energy substrates. This suggests that the transport of amino-acids and energy substrates into the cell are impaired after hypothermic cardiopulmonary bypass and intracellular substrates are utilised for the increased demand for energy during rewarming.

Responses of the pancreatic digestive enzyme secretion to various combinations of amino acids and cholecystokinin in chicks ( Gallus domesticus)

1. 1. Effect of amino acid administration on pancreatic secretion of digestive enzymes, amylase, trypsinogen and chymotrypsinogen was studied after wing vein injection of an amino acid (AAs) mixture (Thr, Lys, Phe, Leu, Ile, Glu, Val, His, and Met) or combinations of selected amino acids, i.e. Thr + Phe + Ile, Thr + Phe, Thr + Ile or Phe + Ile, in the presence of cholecystokinin (CCK) in chicks. 2. 2. Time course changes of enzyme output were similar in all treatment groups having a peak within 10–30 min, except for Phe + Ile that resulted in delayed induction of the enzyme release as shown by significant increases in the last 20 min compared with those in the rest. 3. 3. When increases in enzyme outputs for the first 30 min were compared, it was shown that the three enzyme responses brought about by the administration of the AAs mixture was almost entirely accounted for by the combined injection of Thr + Phe. 4. 4. Neither Thr + Ile nor Phe + Ile was as effective as Thr + Phe in inducing the output of these pancreatic enzymes. 5. 5. The present results suggest that Thr and Phe may have a specific regulatory role in the secretion of pancreatic digestive enzymes in chicks when administered simultaneously.

The effect of amino acid administration on skeletal muscle blood flow

A protein meal increases renal and splanchnic blood flow and this study was undertaken to assess the effect of amino acids on skeletal muscle blood flow. In one group of ten subjects oral water was compared with oral amino acids and in a second group intravenous saline was compared with intravenous amino acids. Oral water produced no change in muscle blood flow while oral amino acids produced a significant increase. Neither intravenous saline nor intravenous amino acids had any significant effect. It is postulated that the increase in tissue blood flow is in all instances due to glomerulopressin, a substance produced in the liver during amino acid metabolism.

The effect of pancreatectomy upon blood sugar and serum amino acid concentration following the administration of amino acids.

T HE ingestion or the infusion of hydrolyzed casein causes the blood sugar concentration to fall.ll 2 One possible explanat,ion for this phenomenon is to assume that an elevation of the serum amino acid level evokes the secretion of insulin. When the opportunity presented itself, therefore, it seemed worthwhiIe to observe the effects of amino acid administration in pancreatectomized individuals,