Amino Acid Derangements in Plasma and Erythrocytes of Patients with Sepsis

Chang, Soon Hee; Cho, Kyung Ja; Chang, Yoon Jong; Song, Kyung Eun; Lee, Won Kil; Kim, Jay Sik

Abstract

BACKGROUND: Sepsis is a major insult leading to increased muscle breakdown and oxidation of amino acids. Disturbed plasma and brain amino acid levels may be important in the altered mental status observed in patients with infections and alteration in mental status due to sepsis has been associated with an increased mortality rate. Erythrocytes have been suggested as transport cells for amino acids and may be better than plasma for utilization and storage of amino acids in the body. Several reports suggested that amino acid alterations in plasma and erythrocytes have had an important role in sepsis. So we investigated the association between severity and prognosis of sepsis and amino acid levels in plasma and erythrocytes.
METHODS
Heparinized plasma and erythrocytes were taken from 25 healthy controls, 10 infected patients and 15 septic patients. The amino acid levels were determined using high performance liquid chromatography after deproteinization with sulfosalicylic acid.
RESULTS
Plasma amino acid pattern showed elevated levels of the aromatic amino acids (tyrosine and phenylalanine) and sulfur-containing amino acid (cystine) but decreased level of branched chain amino acid (isoleucine) in septic patients compared with healthy controls or infected patients. Patients with septic encephalopathy had higher levels of tyrosine, phenylalanine and sulfur-containing amino acid (methionine) than patients without septic encephalopathy. The ratios of erythrocytes to plasma showed no significant decrease in septic patients compared with healthy controls or infected patients. However, in patients with septic encephalopathy, methionine, leucine and phenylalanine levels were lower than in patients without septic encephalopathy.
CONCLUSIONS
The results showed a characteristic pattern of amino acid derangements in plasma and erythrocytes of septic patients. This pattern was more prominent in severe sepsis. It was suggested that the severity and prognosis of septic patients could be predicted by measuring the amino acid levels of plasma and erythrocytes.