Amino acid kinetics during the anhepatic phase of liver transplantation.
Alanine and glutamine are interorgan nitrogen/carbon carriers for ureagenesis and gluconeogenesis, which are mainly but not necessarily only hepatic. The liver is central to alanine and glutamine metabolism, but most organs can produce and use them. We studied amino acid kinetics after liver removal to depict initial events of liver failure and to provide a model to study extrahepatic gluconeogenesis and nitrogen disposal in humans. We measured amino acid kinetics with [5,5,5-(2)H(3)]leucine and [3-(13)C]alanine or [1,2-(13)C(2)]glutamine tracers in 21 subjects during and after the anhepatic phase of liver transplantation: 12 were at 7 months posttransplantation, and 7 were healthy control subjects. Anhepatic leucine kinetics, including proteolysis, was unchanged. Alanine plasma and whole-body contents increased 3x and 2x, with a halved metabolic clearance and a doubled production, 2% greater than disposal. Free whole-body glutamine decreased 25% but increased 50% in plasma. Glutamine clearance was halved, and the production decreased by 25%, still 2% greater than disposal. Liver replacement decreased alanine and glutamine concentrations, leaving leucine unchanged. Liver removal caused doubled alanine fluxes, minor changes in glutamine, and no changes in leucine. The initial events after liver removal are an accumulation of three-carbon compounds, an acceleration of alanine turnover, and limited nitrogen storage in alanine and glutamine.
Battezzati
Alberto
A
Università degli Studi di Milano, Milan, Italy. battezzati.alberto@hsr.it
Caumo
Andrea
A
Fattorini
Annalisa
A
Sereni
Lucia Piceni
LP
Coppa
Jorgelina
J
Romito
Raffaele
R
Ammatuna
Mario
M
Regalia
Enrico
E
Mazzaferro
Vincenzo
V
Luzi
Livio
L
D000409:Alanine / Q000097:blood / Q000378:metabolism; D000596:Amino Acids / Q000097:blood / Q000378:metabolism*; D001786:Blood Glucose / Q000032:analysis; D002245:Carbon Dioxide / Q000097:blood; D002247:Carbon Isotopes; D003903:Deuterium; D004573:Electrolytes / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005943:Gluconeogenesis; D005973:Glutamine / Q000097:blood / Q000378:metabolism; D005990:Glycerol / Q000097:blood; D006400:Hematocrit; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019344:Lactic Acid / Q000097:blood; D007930:Leucine / Q000097:blood / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D016031:Liver Transplantation; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009584:Nitrogen / Q000378:metabolism; D010100:Oxygen / Q000097:blood; D019289:Pyruvic Acid / Q000097:blood
D000596:Amino Acids; D001786:Blood Glucose; D002247:Carbon Isotopes; D004573:Electrolytes; D005230:Fatty Acids, Nonesterified; D005973:Glutamine; D002245:Carbon Dioxide; D019344:Lactic Acid; D019289:Pyruvic Acid; D003903:Deuterium; D007930:Leucine; D009584:Nitrogen; D000409:Alanine; D005990:Glycerol; D010100:Oxygen