The relationship between plasma taurine and other amino acid levels in human sepsis

Although reports of decreased plasma taurine in trauma, sepsis and critical illness are available, very little is known about the relationships among changes in plasma taurine, other amino acid levels and metabolic variables. We analyzed a large series of plasma amino acid profiles obtained in trauma patients with sepsis who were undergoing total parenteral nutrition. The correlations between plasma taurine, other amino acid levels, parenteral substrate doses and metabolic and cardiorespiratory variables were assessed by regression analysis. Post-traumatic hypotaurinemia was followed by partial recovery toward less abnormal values when sepsis developed. Levels of taurine were directly and significantly related to levels of glutamate, aspartate, beta-alanine and phosphoethanolamine (and unrelated to other amino acids). Levels of these amino acids increased simultaneously with increasing doses of leucine, isoleucine and valine in total parenteral nutrition. Decreasing taurine was associated with increasing lactate, arteriovenous O-2 concentration difference and respiratory index, and with decreasing cholesterol and cardiac index. These results characterize the relationships between plasma taurine and other amino acid levels in sepsis, provide evidence of amino acid interactions that may support taurine availability and show more severe decreases in plasma taurine with the worsening of metabolic and cardiorespiratory patterns.