7-day longitudinal proteomics of critically ill patients: a pilot study

Area of Science:

• Proteomics
• Clinical Biochemistry
• Intensive Care Medicine

Background:

• Adult health parameters exhibit stability, typically with <20% variability, barring circadian rhythms.
• Understanding proteome stability is crucial for interpreting biomarker fluctuations in critical care.

Purpose of the Study:

• To investigate the stability of the plasma proteome in intensive care unit (ICU) patients.
• To assess short-term proteome dynamics in relation to clinical parameter heterogeneity.

Main Methods:

• Prospective, observational pilot study involving bottom-up proteomics of blood plasma from adult ICU patients.
• Analysis of 8 week-long batches from 7 patients using MaxQuant software and custom R/Python scripts.
• Statistical analysis including random-effects modeling and Z-score-based hierarchical clustering.

Main Results:

• 218 proteins identified, with 68 consistently detected across all patient samples.
• Most proteins exhibited within-patient variance <30%, with time effects on variance <5%.
• Hierarchical clustering demonstrated patient-specific proteome profiles that remained stable over the observation period.

Conclusions:

• The plasma proteome of ICU patients exhibits individual characteristics and stability over a seven-day period.
• Short-term proteome dynamics were not evident in this pilot cohort, suggesting limited value for daily proteome analysis in this context.