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Methohexital affects neutrophil (PMN) dynamic free amino acid pool and immune functions in vitro
J Mühling1, M Fuchs, A Sablotzki
1Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University, Giessen, Germany.
Background And Objective:
The objective of this study was to determine the dose as well as the duration of exposure-dependent effects of methohexital on neutrophil [polymorphonuclear leucocyte (PMN)] free amino acid profiles and, in a parallel study, on PMN immune functions.
Methods:
Whole blood samples were taken from 20 volunteers and incubated with methohexital [0 (control), 3.6, 26, 130 and 260 microg mL-1] for 10, 30, 60 or 120 min. PMN amino acid profiles were documented using advanced PMN separation and high-performance liquid chromatography procedures. Superoxide anion (O2-) and hydrogen peroxide production (H2O2), and activity of released myeloperoxidase (MPO), were determined photometrically.
Results:
After methohexital, significant dose (> or = 26 microg mL-1) as well as duration of exposure-dependent (> or = 30 min) increases in histidine, isoleucine, leucine, valine, methionine, serine, glycine, threonine, and decreases in glutamine, glutamate, aspartate, asparagine, arginine, ornithine, citrulline, alanine and taurine were observed (P < or = 0.05). Concerning PMN immune functions, methohexital significantly decreased O2-, H2O2 formation and MPO (> or = 26 microg mL-1, > or = 30 min, P < or = 0.05).
Conclusions:
Altogether, there is significant relevance to the pharmacological regimens which enhance the supply of methohexital in whole blood. In regards to our results, we suggest that considerable changes in PMN 'dynamic free amino acid pool', for example induced by methohexital, may be one of the determinants in cell nutrition adversely affecting PMN metabolism. It is partially through its effect on the PMN free amino acid pool that maleficent pharmacological stress may have an unintentional influence on PMN immune functions.
Insights
Methohexital alters neutrophil amino acid profiles and impairs immune functions in a dose- and time-dependent manner. These changes in the free amino acid pool may negatively impact neutrophil metabolism and immune responses.
Area of Science:
- Immunology
- Pharmacology
- Biochemistry
Background:
- Neutrophils (polymorphonuclear leucocytes, PMNs) play a critical role in the immune system.
- Methohexital is an anesthetic agent with potential immunomodulatory effects.
- Understanding methohexital's impact on PMNs is crucial for patient safety and therapeutic strategies.
Purpose of the Study:
- To investigate the dose- and duration-dependent effects of methohexital on neutrophil free amino acid profiles.
- To evaluate the impact of methohexital on key neutrophil immune functions.
Main Methods:
- Whole blood from 20 volunteers was incubated with varying concentrations of methohexital for different durations.
- Neutrophil separation and high-performance liquid chromatography were used to analyze amino acid profiles.
- Photometric assays measured superoxide anion and hydrogen peroxide production, and myeloperoxidase activity.
Main Results:
- Methohexital significantly altered neutrophil amino acid profiles, increasing some (e.g., histidine, leucine) and decreasing others (e.g., glutamine, arginine) in a dose- and time-dependent manner.
- Methohexital significantly reduced superoxide anion and hydrogen peroxide production, and myeloperoxidase activity in neutrophils.
- Observed effects were significant at concentrations of 26 microg mL-1 and exposure durations of 30 minutes or longer.
Conclusions:
- Methohexital significantly impacts the dynamic free amino acid pool within neutrophils.
- These alterations in amino acid profiles may adversely affect neutrophil metabolism and function.
- Pharmacological strategies involving methohexital should consider its unintended influence on neutrophil immune functions.