Hypothermia prolongs activation of NF-kappaB and augments generation of inflammatory cytokines.
Am J Physiol Cell Physiol
; 287(2): C422-31, 2004 Aug.
Article
em En
| MEDLINE
| ID: mdl-15070815
ABSTRACT
While moderate hypothermia is protective against ischemic cardiac and brain injury, it is associated with much higher mortality in patients with sepsis. We previously showed that in vitro exposure to moderate hypothermia (32 degrees C) delays the induction and prolongs the duration of TNF-alpha and IL-1beta secretion by lipopolysaccharide (LPS)-stimulated human mononuclear phagocytes. In the present study, we extended these observations by showing that moderate hypothermia exerts effects on TNF-alpha and IL-1beta generation in the human THP-1 monocyte cell line that are similar to those that we previously found in primary cultured monocytes; that hypothermia causes comparable changes in cytokine generation stimulated by zymosan, toxic shock syndrome toxin-1, and LPS; and that hypothermia causes similar changes in TNF-alpha and IL-1beta mRNA accumulation. TNF-alpha mRNA half-life, determined after transcriptional arrest with actinomycin D, was not significantly prolonged by lowering incubation temperature from 37 to 32 degrees C, suggesting that hypothermia modifies TNF-alpha gene transcription. This finding was further supported by reporter gene studies showing a threefold increase in activity of the human TNF-alpha promoter at 32 vs. 37 degrees C. Electrophoretic mobility shift assay revealed that hypothermia prolonged NF-kappaBeta activation, identifying a potential role for this transcription factor in mediating the effects of hypothermia on TNF-alpha and IL-1beta production. Delayed reexpression of the inhibitor IkappaBalpha, shown by Northern blotting and immunoblotting, may account in part for the prolonged NF-kappaBeta activation at 32 degrees C. Augmentation of NF-kappaBeta-dependent gene expression during prolonged exposure to hypothermia may be a common mechanism leading to increased lethality in sepsis, late-onset systemic inflammatory response syndrome after accidental hypothermia, and neuroprotection after ischemia.
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Base de dados:
MEDLINE
Assunto principal:
Monócitos
/
NF-kappa B
/
Interleucina-1
/
Fator de Necrose Tumoral alfa
/
Hipotermia Induzida
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Am J Physiol Cell Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Estados Unidos