Does hemodialysis increase protein breakdown? Dissociation between whole-body amino acid turnover and regional muscle kinetics

Hemodialysis (HD) is a protein catabolic procedure. Whole-body amino acid turnover studies identify dialysate amino acid loss and reduced protein synthesis as the catabolic events; proteolysis is not increased. Regional amino acid kinetics, however, document enhanced muscle protein breakdown as the...

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Bibliographic Details
Published in:Journal of the American Society of Nephrology 2005-04, Vol.16 (4), p.862-868
Main Authors: LIM, Victoria S, IKIZLER, T. Alp, RAJ, Dominic S. C, FLANIGAN, Michael J
Format: Article
Language:English
Subjects:
Amino Acids - metabolism
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
Biological and medical sciences
Emergency and intensive care: renal failure. Dialysis management
Humans
Intensive care medicine
Kinetics
Medical sciences
Muscle Proteins - metabolism
Muscles - metabolism
Nephrology. Urinary tract diseases
Renal Dialysis
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Summary:Hemodialysis (HD) is a protein catabolic procedure. Whole-body amino acid turnover studies identify dialysate amino acid loss and reduced protein synthesis as the catabolic events; proteolysis is not increased. Regional amino acid kinetics, however, document enhanced muscle protein breakdown as the cause of the catabolism; muscle protein synthesis also increased but to a lesser magnitude than the increment in protein breakdown. This discordance between whole-body and regional kinetics is best explained by the contrasting physiology between the muscle and the liver. During HD, muscle releases amino acids, which then are taken up by the liver for de novo protein synthesis. There seems to be a somatic to visceral recycling of amino acids. Evidence supporting this concept includes the increased fractional synthesis of albumin and fibrinogen during HD. It should be emphasized that region- or organ-specific kinetics vary, and whole-body turnover is a composite of all of the visceral and somatic compartments taken together. Reduced whole-body protein synthesis may be a compensatory adaptation to dialysate amino acid loss with a consequent reduction in plasma amino acid concentration. Notwithstanding the protein catabolic nature of HD, evidence is accumulating that intradialytic nutritional supplementation may blunt its catabolic effect.
ISSN:1046-6673
1533-3450
DOI:10.1681/asn.2004080624