Intrahepatic synthesis of tumor necrosis factor-alpha related to cardiac surgery is inhibited by interleukin-10 via the Janus kinase (Jak)/signal transducers and activator of transcription (STAT) pathway.
OBJECTIVES To identify the signaling pathways involved in the anti-inflammatory shift of the cytokine balance due to hypothermia during cardiopulmonary bypass. DESIGN Experimental animal study. SETTING Department of experimental surgery of a university hospital. SUBJECTS Young pigs. INTERVENTIONS Animals underwent normothermic (37 degrees C) or hypothermic (28 degrees C) cardiopulmonary bypass (n = 6 each). Samples of liver tissue were taken before and 6 hrs after cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS Intrahepatic expression of tumor necrosis factor-alpha, interleukin-10, inducible nitric oxide synthase, and suppressor of cytokine signaling-3 was detected by reverse transcriptase polymerase chain reaction and/or Western blotting. Concentrations of the inhibitory protein of nuclear factor-kappaB, IkappaB, and of the signal transducer and activator of transcription (STAT)-3 were measured by Western blotting. The DNA-binding activity of nuclear factor-kappaB and STAT-3 was assessed by electrophoretic mobility shift and supershift assays. Liver cell necrosis and apoptosis were assessed by histology and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, respectively. Pigs operated on in hypothermia showed significantly higher intrahepatic concentrations of interleukin-10 and lower concentrations of tumor necrosis factor-alpha than the others. They also showed a lower percentage of hepatic cell necrosis but not of apoptosis. This anti-inflammatory reaction observed in the hypothermic group was associated with a higher expression of suppressor of cytokine signaling-3 and with increased activation of STAT-3. Activation of nuclear factor-kappaB and expression of inducible nitric oxide synthase, however, were not significantly different between both groups. CONCLUSION Our results show that hypothermia during cardiopulmonary bypass up-regulates interleukin-10 via STAT-3 activation, which in turn leads to the attenuation of tumor necrosis factor-alpha expression and to hepatic protection.
Qing
Ma
M
German Heart Center Munich, Technical University, Munich, Germany. ma@dhm.mhn.de
Nimmesgern
Ariane
A
Heinrich
Peter C
PC
Schumacher
Kathrin
K
Vazquez-Jimenez
Jaime F
JF
Hess
John
J
von Bernuth
Götz
G
Seghaye
Marie-Christine
MC
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D004195:Disease Models, Animal; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D007036:Hypothermia, Induced; D020287:In Situ Nick-End Labeling; D007249:Inflammation; D016753:Interleukin-10 / Q000032:analysis / Q000502:physiology*; D053613:Janus Kinase 1; D008099:Liver / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000032:analysis / Q000502:physiology; D009336:Necrosis; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000502:physiology*; D011506:Proteins / Q000032:analysis / Q000502:physiology*; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D015854:Up-Regulation
D016328:NF-kappa B; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D011505:Protein-Tyrosine Kinases; D053613:Janus Kinase 1