Plasma amino acid profiles reveal metabolic signatures of mortality and infection in critically ill surgical patients requiring parenteral nutrition: A longitudinal analysis.

Authors

Lucia A Gonzalez Ramirez, Dean P Jones, Kirk A Easley, Donghai Liang, George A Cotsonis, John R Galloway, Mengyuan Ren, Daniel P Griffith, Nisha J Dave, Kenneth A Kudsk, Harry C Sax, Addison K May, Paul E Wischmeyer, Henry M Blumberg, Jessica A Alvarez, Thomas R Ziegler

Published in

Clinical nutrition (Edinburgh, Scotland). Volume 67. Pages 106819. Oct 12, 2026. Epub Oct 12, 2026.

Abstract

Surgical intensive care unit (SICU) patients experience high rates of adverse outcomes, underscoring the need for insights into pathophysiology. We aimed to evaluate associations between plasma amino acids (AAs), post-surgical mortality, and hospital-acquired infections in SICU patients requiring parenteral nutrition (PN).
Secondary analysis of a multicenter trial including 148 adults receiving glutamine-supplemented or standard PN after major surgery. Levels of plasma AAs were quantified at baseline, Day 3, and Day 7. Mortality and infections were monitored through day 28. Associations between AAs and outcomes were assessed via generalized linear models adjusted for clinical covariates. Machine learning models evaluated the classification performance of AAs.
At baseline, a four AA signature (plasma aspartate, histidine, leucine, and methionine concentrations) showed similar discrimination of 28-day mortality as the APACHE II score (AUC 0.88 vs. 0.78, DeLong test P = 0.28). Increased concentrations of these AA suggest impaired uptake and utilization. At baseline, BSI was best classified by a model that included decreased concentrations of alanine, cystine, glutamate, glutamine, and lysine (AUC 0.79), with glutamate elevated in cases. The best classification model for pneumonia at Day 7 included decreased cystine, lysine, ornithine, threonine, tyrosine, and valine concentrations (AUC 0.86). At baseline and Day 7, for any infections, the classification model included decreased glutamine, glycine, lysine, ornithine, proline, serine, threonine, and valine concentrations (AUC >0.79).
Elevated essential AA concentrations were associated with SICU mortality, while lower levels of both essential and non-essential AAs were linked to hospital-acquired infections.

PMID:
42933108
Bibliographic data and abstract were imported from PubMed on 27 Oct 2026.

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