Plasma Amino Acids as Markers of Liver Dysfunction in Cirrhotics

Abstract

To determine the role of liver dysfunction in the plasma amino acid profile of cirrhotic patients, we correlated basal plasma amino acids and several biochemical and functional hepatic variables in 29 cirrhotics with normal mental state or mild encephalopathy. Increased levels of aromatic amino acids and free tryptophan correlated positively with the extent of portosystemic shunt, as assessed by the ammonia tolerance test (r = 0.758 and r = 0.589, respectively). There was a negative correlation between these amino acids and liver function, as evaluated by the galactose elimination capacity test (r = −0.657 and r = −0.551), thus suggesting that phenylalanine, tyrosine, and free tryptophan may be considered indexes of liver dysfunction in non-comatose cirrhotics.

Key-words:

• Aromatic amino acids
• branched-chain amino acids
• cirrhosis
• liver function
• methionine
• portosyslemic shunt
• tryptophan