Muscle wasting in emphysema

1988 ◽  
Vol 75 (4) ◽  
pp. 415-420 ◽  
Author(s):  
W. L. Morrison ◽  
J. N. A. Gibson ◽  
C. Scrimgeour ◽  
M. J. Rennie
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Protein Breakdown ◽  
Body Protein ◽  
Net Protein

1. We have investigated arteriovenous exchanges of tyrosine and 3-methylhistidine across leg tissue in the postabsorptive state as specific indicators of net protein balance and myofibrillar protein breakdown, respectively, in eight patients with emphysema and in 11 healthy controls. Whole-body protein turnover was measured using l-[1-13C]leucine. 2. Leg efflux of tyrosine was increased by 47% in emphysematous patients compared with normal control subjects, but 3-methylhistidine efflux was not significantly altered. 3. In emphysema, whole-body leucine flux was normal, whole-body leucine oxidation was increased, and whole-body protein synthesis was depressed. 4. These results indicate that the predominant mechanism of muscle wasting in emphysema is a fall in muscle protein synthesis, which is accompanied by an overall fall in whole-body protein turnover.

Skeletal muscle and whole-body protein turnover in cirrhosis

1990 ◽  
Vol 78 (6) ◽  
pp. 613-619 ◽  
Author(s):  
W. L. Morrison ◽  
I. A. D. Bouchier ◽  
J. N. A. Gibson ◽  
M. J. Rennie
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Body Protein ◽  
Control Subjects ◽  
Healthy Control ◽  
Cirrhotic Patients ◽  
Net Protein

1. We investigated arteriovenous exchanges of tyrosine and 3-methylhistidine across leg tissue in the postabsorptive state as specific indices of net protein balance and myofibrillar protein breakdown, respectively, in eight patients with cirrhosis and in 11 healthy control subjects. Whole-body protein turnover was also measured using l-[1-13C]leucine. 2. Leg efflux of tyrosine was 45% greater in cirrhotic patients than in normal control subjects [−6.5(1.4 to −19.1) vs −4.2 (−2.2 to −7.7) μmol min−1 100 mg−1 of leg, median (range), P <0.025]. 3-Methylhistidine efflux was not significantly altered. 3. In cirrhosis, whole-body leucine flux was normal but whole-body leucine oxidation was elevated so that whole-body protein synthesis was depressed by 17%. 4. The results indicate the predominant mechanism of muscle wasting in cirrhosis to be a fall in muscle protein synthesis, which is accompanied by an overall fall in whole-body protein turnover.

scholarly journals Muscle Protein Synthesis and Whole-Body Protein Turnover Responses to Ingesting Essential Amino Acids, Intact Protein, and Protein-Containing Mixed Meals with Considerations for Energy Deficit

Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2457 ◽  
Author(s):  
Jess A. Gwin ◽  
David D. Church ◽  
Robert R. Wolfe ◽  
Arny A. Ferrando ◽  
Stefan M. Pasiakos
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Energy Deficit ◽  
Whole Body ◽  
Intact Protein ◽  
Body Protein ◽  
Protein Feeding

Protein intake recommendations to optimally stimulate muscle protein synthesis (MPS) are derived from dose-response studies examining the stimulatory effects of isolated intact proteins (e.g., whey, egg) on MPS in healthy individuals during energy balance. Those recommendations may not be adequate during periods of physiological stress, specifically the catabolic stress induced by energy deficit. Providing supplemental intact protein (20–25 g whey protein, 0.25–0.3 g protein/kg per meal) during strenuous military operations that elicit severe energy deficit does not stimulate MPS-associated anabolic signaling or attenuate lean mass loss. This occurs likely because a greater proportion of the dietary amino acids consumed are targeted for energy-yielding pathways, whole-body protein synthesis, and other whole-body essential amino acid (EAA)-requiring processes than the proportion targeted for MPS. Protein feeding formats that provide sufficient energy to offset whole-body energy and protein-requiring demands during energy deficit and leverage EAA content, digestion, and absorption kinetics may optimize MPS under these conditions. Understanding the effects of protein feeding format-driven alterations in EAA availability and subsequent changes in MPS and whole-body protein turnover is required to design feeding strategies that mitigate the catabolic effects of energy deficit. In this manuscript, we review the effects, advantages, disadvantages, and knowledge gaps pertaining to supplemental free-form EAA, intact protein, and protein-containing mixed meal ingestion on MPS. We discuss the fundamental role of whole-body protein balance and highlight the importance of comprehensively assessing whole-body and muscle protein kinetics when evaluating the anabolic potential of varying protein feeding formats during energy deficit.

Prolonged bed rest decreases skeletal muscle and whole body protein synthesis

1996 ◽  
Vol 270 (4) ◽  
pp. E627-E633 ◽  
Author(s):  
A. A. Ferrando ◽  
H. W. Lane ◽  
C. A. Stuart ◽  
J. Davis-Street ◽  
R. R. Wolfe
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Bed Rest ◽  
Whole Body ◽  
Protein Breakdown ◽  
Skeletal Muscle Protein ◽  
Model Calculations ◽  
Body Protein

We sought to determine the extent to which the loss of lean body mass and nitrogen during inactivity was due to alterations in skeletal muscle protein metabolism. Six male subjects were studied during 7 days of diet stabilization and after 14 days of stimulated microgravity (-6 degrees bed rest). Nitrogen balance became more negative (P < 0.03) during the 2nd wk of bed rest. Leg and whole body lean mass decreased after bed rest (P < 0.05). Serum cortisol, insulin, insulin-like growth factor I, and testosterone values did not change. Arteriovenous model calculations based on the infusion of L-[ring-13C6]-phenylalanine in five subjects revealed a 50% decrease in muscle protein synthesis (PS; P < 0.03). Fractional PS by tracer incorporation into muscle protein also decreased by 46% (P < 0.05). The decrease in PS was related to a corresponding decrease in the sum of intracellular amino acid appearance from protein breakdown and inward transport. Whole body protein synthesis determined by [15N]alanine ingestion on six subjects also revealed a 14% decrease (P < 0.01). Neither model-derived nor whole body values for protein breakdown change significantly. These results indicate that the loss of body protein with inactivity is predominantly due to a decrease in muscle PS and that this decrease is reflected in both whole body and skeletal muscle measures.

Muscle protein metabolism in female swimmers after a combination of resistance and endurance exercise

1996 ◽  
Vol 81 (5) ◽  
pp. 2034-2038 ◽  
Author(s):  
Kevin D. Tipton ◽  
Arny A. Ferrando ◽  
Bradley D. Williams ◽  
Robert R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Endurance Exercise ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Protein Breakdown ◽  
Body Protein ◽  
Muscle Protein Metabolism

Tipton, Kevin D., Arny A. Ferrando, Bradley D. Williams, and Robert R. Wolfe. Muscle protein metabolism in female swimmers after a combination of resistance and endurance exercise. J. Appl. Physiol. 81(5): 2034–2038, 1996.—There is little known about the responses of muscle protein metabolism in women to exercise. Furthermore, the effect of adding resistance training to an endurance training regimen on net protein anabolism has not been established in either men or women. The purpose of this study was to quantify the acute effects of combined swimming and resistance training on protein metabolism in female swimmers by the direct measurement of muscle protein synthesis and whole body protein degradation. Seven collegiate female swimmers were each studied on four separate occasions with a primed constant infusion of ring-[13C6]phenylalanine (Phe) to measure the fractional synthetic rate (FSR) of the posterior deltoid and whole body protein breakdown. Measurements were made over a 5-h period at rest and after each of three randomly ordered workouts: 1) 4,600 m of intense interval swimming (SW); 2) a whole body resistance-training workout with no swimming on that day (RW); and 3) swimming and resistance training combined (SR). Whole body protein breakdown was similar for all treatments (0.75 ± 0.04, 0.69 ± 0.03, 0.69 ± 0.02, and 0.71 ± 0.04 μmol ⋅ min−1 ⋅ kg−1for rest, RW, SW, and SR, respectively). The FSR of the posterior deltoid was significantly greater ( P< 0.05) after SR (0.082 ± 0.015%/h) than at rest (0.045 ± 0.006%/h). There was no significant difference in the FSR after RW (0.048 ± 0.004%/h) or SW (0.064 ± 0.008%/h) from rest or from SR. These data indicate that the combination of swimming and resistance exercise stimulates net muscle protein synthesis above resting levels in female swimmers.

Effect of glycogen availability on human skeletal muscle protein turnover during exercise and recovery

2010 ◽  
Vol 109 (2) ◽  
pp. 431-438 ◽  
Author(s):  
Krista R. Howarth ◽  
Stuart M. Phillips ◽  
Maureen J. MacDonald ◽  
Douglas Richards ◽  
Natalie A. Moreau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Whole Body ◽  
Skeletal Muscle Protein ◽  
Protein Balance ◽  
Body Protein ◽  
Muscle Protein Turnover ◽  
Net Protein

We examined the effect of carbohydrate (CHO) availability on whole body and skeletal muscle protein utilization at rest, during exercise, and during recovery in humans. Six men cycled at ∼75% peak O2 uptake (V̇o2peak) to exhaustion to reduce body CHO stores and then consumed either a high-CHO (H-CHO; 71 ± 3% CHO) or low-CHO (L-CHO; 11 ± 1% CHO) diet for 2 days before the trial in random order. After each dietary intervention, subjects received a primed constant infusion of [1-13C]leucine and l-[ring-2H5]phenylalanine for measurements of the whole body net protein balance and skeletal muscle protein turnover. Muscle, breath, and arterial and venous blood samples were obtained at rest, during 2 h of two-legged kicking exercise at ∼45% of kicking V̇o2peak, and during 1 h of recovery. Biopsy samples confirmed that the muscle glycogen concentration was lower in the L-CHO group versus the H-CHO group at rest, after exercise, and after recovery. The net leg protein balance was decreased in the L-CHO group compared with at rest and compared with the H-CHO condition, which was primarily due to an increase in protein degradation (area under the curve of the phenylalanine rate of appearance: 1,331 ± 162 μmol in the L-CHO group vs. 786 ± 51 μmol in the H-CHO group, P < 0.05) but also due to a decrease in protein synthesis late in exercise. There were no changes during exercise in the rate of appearance compared with rest in the H-CHO group. Whole body leucine oxidation increased above rest in the L-CHO group only and was higher than in the H-CHO group. The whole body net protein balance was reduced in the L-CHO group, largely due to a decrease in whole body protein synthesis. These data extend previous findings by others and demonstrate, using contemporary stable isotope methodology, that CHO availability influences the rates of skeletal muscle and whole body protein synthesis, degradation, and net balance during prolonged exercise in humans.

Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise

2006 ◽  
Vol 31 (5) ◽  
pp. 518-529 ◽  
Author(s):  
Sarah B. Wilkinson ◽  
Paul L. Kim ◽  
David Armstrong ◽  
Stuart M. Phillips
Keyword(s):  
Protein Synthesis ◽  
Muscle Glycogen ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Breakdown Rate ◽  
Body Protein ◽  
Post Exercise ◽  
Glycogen Resynthesis

We examined the effect of a post-exercise oral carbohydrate (CHO, 1 g·kg–1·h–1) and essential amino acid (EAA, 9.25 g) solution containing glutamine (0.3 g/kg BW; GLN trial) versus an isoenergetic CHO–EAA solution without glutamine (control, CON trial) on muscle glycogen resynthesis and whole-body protein turnover following 90 min of cycling at 65% VO2 peak. Over the course of 3 h of recovery, muscle biopsies were taken to measure glycogen resynthesis and mixed muscle protein synthesis (MPS), by incorporation of [ring-2H5] phenylalanine. Infusion of [1-13C] leucine was used to measure whole-body protein turnover. Exercise resulted in a significant decrease in muscle glycogen (p < 0.05) with similar declines in each trial. Glycogen resynthesis following 3 h of recovery indicated no difference in total accumulation or rate of repletion. Leucine oxidation increased 2.5 fold (p < 0.05) during exercise, returned to resting levels immediately post-exercise,and was again elevated at 3 h post-exercise (p < 0.05). Leucine flux, an index of whole-body protein breakdown rate, was reduced during exercise, but increased to resting levels immediately post-exercise, and was further increased at 3 h post-exercise (p < 0.05), but only during the CON trial. Exercise resulted in a marked suppression of whole-body protein synthesis (50% of rest; p < 0.05), which was restored post-exercise; however, the addition of glutamine did not affect whole-body protein synthesis post-exercise. The rate of MPS was not different between trials. The addition of glutamine to a CHO + EAA beverage had no effect on post-exercise muscle glycogen resynthesis or muscle protein synthesis, but may suppress a rise in whole-body proteolysis during the later stages of recovery.

Rapid measurement of whole body and forearm protein turnover using a [2H5]phenylalanine model

1989 ◽  
Vol 256 (5) ◽  
pp. E631-E639 ◽  
Author(s):  
G. N. Thompson ◽  
P. J. Pacy ◽  
H. Merritt ◽  
G. C. Ford ◽  
M. A. Read ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Rapid Assessment ◽  
Whole Body ◽  
Co2 Production ◽  
Constant Infusion ◽  
Body Protein ◽  
Normal Adults

Whole body protein turnover was measured in six normal adults using a model based on a primed constant infusion of [2H5]phenylalanine and, independently, by an established method of a primed constant infusion of [1-13C]leucine. Isotopic plateau in plasma was achieved within 2 h for [2H5]phenylalanine and, in four of the subjects who received a priming dose of [2H4]tyrosine, for [2H4]tyrosine. In all subjects whole body protein turnover measured with the phenylalanine model (mean protein synthesis, 2.65 +/- (SD) 0.16 g.kg-1.24 h-1; catabolism, 3.58 +/- 0.26 g.kg-1.24 h-1) was similar to that measured using the leucine model (synthesis, 3.09 +/- 0.27 g.kg-1.24 h-1; catabolism, 3.70 +/- 0.35 g.kg-1.24 h-1). Mean forearm fractional muscle protein synthesis calculated by the phenylalanine model was 0.06 +/- 0.03%/h, which compares closely with literature values derived by other methods. The phenylalanine model allows the rapid assessment of whole body and muscle protein turnover from plasma samples alone, obviating the need for measurement of expired air CO2 production or enrichment.

Short-term growth hormone treatment does not increase muscle protein synthesis in experienced weight lifters

1993 ◽  
Vol 74 (6) ◽  
pp. 3073-3076 ◽  
Author(s):  
K. E. Yarasheski ◽  
J. J. Zachweija ◽  
T. J. Angelopoulos ◽  
D. M. Bier
Keyword(s):  
Growth Hormone ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Protein Breakdown ◽  
Short Term ◽  
Body Protein ◽  
Fractional Rate ◽  
Weight Lifters

The purpose of this study was to determine whether recombinant human growth hormone (GH) administration enhances muscle protein anabolism in experienced weight lifters. The fractional rate of skeletal muscle protein synthesis and the whole body rate of protein breakdown were determined during a constant intravenous infusion of [13C]leucine in 7 young (23 +/- 2 yr; 86.2 +/- 4.6 kg) healthy experienced male weight lifters before and at the end of 14 days of subcutaneous GH administration (40 microgram.kg-1 x day-1). GH administration increased fasting serum insulin-like growth factor-I (from 224 +/- 20 to 589 +/- 80 ng/ml, P = 0.002) but did not increase the fractional rate of muscle protein synthesis (from 0.034 +/- 0.004 to 0.034 +/- 0.002%/h) or reduce the rate of whole body protein breakdown (from 103 +/- 4 to 108 +/- 5 mumol.kg-1 x h-1). These findings suggest that short-term GH treatment does not increase the rate of muscle protein synthesis or reduce the rate of whole body protein breakdown, metabolic alterations that would promote muscle protein anabolism in experienced weight lifters attempting to further increase muscle mass.

The 1987 Borden Award Lecture.: Protein metabolism in premature human infants

1988 ◽  
Vol 66 (9) ◽  
pp. 1247-1252 ◽  
Author(s):  
Paul B. Pencharz
Keyword(s):  
Protein Synthesis ◽  
Premature Infants ◽  
Protein Metabolism ◽  
Protein Turnover ◽  
Very Low Birth Weight ◽  
Muscle Protein ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Body Protein ◽  
Positive Balance

Our studies have focused on the regulation of whole body and skeletal muscle protein metabolism in premature infants. Net deposition of protein is the result of a positive balance between protein synthesis and breakdown. To measure protein metabolism we have employed end-product studies with [15N]glycine and 13[C]leucine. Myofibrillar protein degradation was estimated by measuring the excretion of N-t-methylhistidine in urine. Energy expenditure and substrate utilization were also measured. Premature infants have high rates of protein synthesis (12 g∙kg−1∙d−1), twice those measured in children and four times those found in adults. Intrauterine malnourished babies have increased rates of protein turnover. Very low birth weight infants (< 1500 g) have higher myofibrillar protein turnover than larger babies. Intravenous feeding decreases whole body protein turnover, and we estimate visceral protein synthesis to be approximately 4 g∙kg−1∙d−1. Suboptimal energy intake worsens nitrogen utilization by reducing the reutilization of endogenous amino acids for protein synthesis. We have also examined the effects of varying the source of nonprotein energy (i.e., glucose only versus glucose plus lipid) at requirement levels and have shown there is no effect on protein metabolism. Recent improvements in technology have opened the way to detailed study of individual amino acid metabolism in neonates in the future.

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