Endotoxemia-induced inflammation and the effect on the human brain.
BACKGROUND
Effects of systemic inflammation on cerebral function are not clear, as both inflammation-induced encephalopathy as well as stress-hormone mediated alertness have been described.


METHODS
Experimental endotoxemia (2 ng/kg Escherichia coli lipopolysaccharide [LPS]) was induced in 15 subjects, whereas 10 served as controls. Cytokines (TNF-alpha, IL-6, IL1-RA and IL-10), cortisol, brain specific proteins (BSP), electroencephalography (EEG) and cognitive function tests (CFTs) were determined.


RESULTS
Following LPS infusion, circulating pro- and anti-inflammatory cytokines, and cortisol increased (P < 0.0001). BSP changes stayed within the normal range, in which neuron specific enolase (NSE) and S100-beta changed significantly. Except in one subject with a mild encephalopathic episode, without cognitive dysfunction, endotoxemia induced no clinically relevant EEG changes. Quantitative EEG analysis showed a higher state of alertness detected by changes in the central region, and peak frequency in the occipital region. Improved CFTs during endotoxemia was found to be due to a practice effect as CFTs improved to the same extent in the reference group. Cortisol significantly correlated with a higher state of alertness detected on the EEG. Increased IL-10 and the decreased NSE both correlated with improvement of working memory and with psychomotor speed capacity. No other significant correlations between cytokines, cortisol, EEG, CFT and BSP were found.


CONCLUSIONS
Short-term systemic inflammation does not provoke or explain the occurrence of septic encephalopathy, but primarily results in an inflammation-mediated increase in cortisol and alertness.


BACKGROUND
NCT00513110.
van den Boogaard
Mark
M
Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, Nijmegen 6500HB, the Netherlands. m.vandenboogaard@ic.umcn.nl
Ramakers
Bart P
BP
van Alfen
Nens
N
van der Werf
Sieberen P
SP
Fick
Wilhelmina F
WF
Hoedemaekers
Cornelia W
CW
Verbeek
Marcel M
MM
Schoonhoven
Lisette
L
van der Hoeven
Johannes G
JG
Pickkers
Peter
P
D000328:Adult; D001921:Brain / Q000276:immunology* / Q000378:metabolism; D001927:Brain Diseases / Q000276:immunology; D002986:Clinical Trials as Topic; D003071:Cognition / Q000502:physiology; D016207:Cytokines / Q000097:blood / Q000187:drug effects; D004569:Electroencephalography; D019446:Endotoxemia / Q000150:complications / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007249:Inflammation; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000276:immunology / Q000378:metabolism; D008297:Male; D055815:Young Adult
D016207:Cytokines; D008070:Lipopolysaccharides; D006854:Hydrocortisone
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