Whole blood leukocyte mitogen activated protein kinases activation differentiates intensive care unit patients with systemic inflammatory response syndrome and sepsis.
BACKGROUND
We sought to determine whether leukocytes from intensive care unit (ICU) patients have altered ERK and p38 kinase activation and specifically if septic patients manifest changes of endotoxin (lipopolysaccharide [LPS]) tolerance. In vitro pretreatment of monocytes (Mono) with LPS induces LPS tolerance with impaired cytokine release and inhibition of ERK and p38 activation after LPS rechallenge.


OBJECTIVE
We hypothesized that macrophage dysregulation, similar to that seen with in vitro LPS tolerance, occurs in critically ill patients with severe sepsis.


METHODS
Heparinized whole blood from 16 surgical ICU patients and 16 healthy controls was incubated for 15 minutes +/- 10 ng/mL LPS at 37 degrees C. Mono and neutrophil (polymorphonuclear leukocytes [PMN]) diphospho (active) ERK and p38 kinase activation were determined using flow cytometry with monoclonal antibodies. Results are expressed as mean +/- SEM of basal and percentage change (delta %) in positive cells (delta = LPS stimulated - basal). Chi2 test was used for statistics.


RESULTS
Basal ERK was seen in Mono from all groups, but delta % positive only increased in healthy subjects and systemic inflammatory response syndrome (SIRS) patients. No basal Mono or PMN p38 was seen in healthy controls, but LPS significantly activated p38 in both cell types. Mono from patients with sepsis, but not SIRS, had impaired ERK activation. Both PMN and Mono from patients with SIRS had low basal but high LPS-stimulated p38, whereas p38 activation was impaired in patients with sepsis.


CONCLUSIONS
Alterations in mitogen activated protein kinases (MAPK) activation are seen in ICU patients. Leukocytes of septic patients, but not those with SIRS, showed characteristics of LPS tolerance. Assessment of leukocyte MAPK activation may identify and differentiate patients with sepsis from those with SIRS.
West
Michael A
MA
Department of Surgery, Feinberg School of Medicine, Northwestern University, IL 60611, USA. mwest@northwestern.edu
Koons
Ann
A
Crandall
Marie
M
Skinner
Ruby
R
Worley
Marcie
M
Shapiro
Michael B
MB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007362:Intensive Care Units; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects; D010865:Pilot Projects; D015398:Signal Transduction / Q000187:drug effects*; D018746:Systemic Inflammatory Response Syndrome / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*
D008070:Lipopolysaccharides; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases