Cholestatic liver injury increases circulating TNF-alpha and IL-6 and mortality after Escherichia coli endotoxemia.
We employed a bile duct ligation (BDL) model of cholestatic liver injury to test the hypothesis that this form of preexisting hepatic dysfunction alters the kinetics of circulating TNF-alpha and IL-6 after Escherichia coli endotoxemia, thereby augmenting mortality and lung injury by a TNF-alpha:leukotriene (LT) axis of inflammation. Male rats were catheterized 13 d after BDL or sham surgery and studied while awake 18 to 24 h later. Cholestasis after BDL was confirmed by baseline serum bilirubin (BDL = 7.34 +/- 0.72 mg/dl, mean +/- SEM, n = 17 versus Sham = 0.25 +/- 0.07, n = 20; p < 0.005) and histopathology. Sham and BDL animals received E. coli lipopolysaccharide serotype O55:B5 (LPS, 5 mg/kg i.v.) or 0.9% NaCl (NS) ending at t = 0 and were monitored over 24 h for vital signs and hemodynamics. In parallel studies, lipoxygenase inhibition was performed using diethylcarbamazine or the 5-lipoxygenase activating-protein inhibitor MK-886. Blood was collected at baseline and at t = 1.5, 3.5, and 24 h for formed elements and for serum endotoxin, TNF-alpha, IL-6, bilirubin, and alanine aminotransferase (ALT). Organs were evaluated at 24 h for histopathology, including neutrophil (PMN) densities and wet/dry weight (W/D) ratios. Cholestasis reduced survival after otherwise nonlethal endotoxemia, with seven of 11 BDL + LPS rats dying within 24 h versus no deaths in BDL + NS (n = 6), Sham + LPS (n = 14), or Sham + NS (n = 6) animals (p < 0.01). Despite equivalent serum endotoxin between groups, circulating TNF-alpha was 8-fold higher in BDL + LPS than in Sham + LPS rats at 1.5 and 3.5 h (p < 0.001), whereas serum TNF-alpha did not differ between BDL + NS and Sham + NS rats. IL-6 likewise was increased differentially by 1.5 h in BDL + LPS animals (11.98 +/- 2.42 ng/ml) versus Sham + LPS rats (3.05 +/- 0.58 ng/ml, p < 0.05). Hypothermia, bradycardic hypotension, and leukopenia were most severe and prolonged in BDL + LPS rats, which also had significantly higher ALT values, W/D ratios, and organ PMN counts. LT inhibition failed to reduce BDL-related differences in serum cytokines or survival after endotoxemia. Thus, cholestasis augments inflammatory responses to gram-negative endotoxemia, sensitizing the host to enhanced fluid flux in multiple organs and to mortality by a LT-independent mechanism.
Lechner
A J
AJ
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, Missouri 63104-1028, USA. lechnera@wpogate.slu.edu
Velasquez
A
A
Knudsen
K R
KR
Johanns
C A
CA
Tracy
T F
TF
Matuschak
G M
GM
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001663:Bilirubin / Q000097:blood; D002779:Cholestasis / Q000150:complications*; D003135:Common Bile Duct; D019446:Endotoxemia / Q000097:blood* / Q000150:complications / Q000401:mortality / Q000473:pathology; D004927:Escherichia coli Infections / Q000097:blood* / Q000150:complications / Q000401:mortality / Q000473:pathology; D015850:Interleukin-6 / Q000097:blood*; D008026:Ligation; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D008099:Liver / Q000473:pathology; D008107:Liver Diseases / Q000150:complications* / Q000209:etiology / Q000473:pathology; D008168:Lung / Q000473:pathology; D008297:Male; D009504:Neutrophils / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
D015850:Interleukin-6; D016859:Lipoxygenase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D000410:Alanine Transaminase; D001663:Bilirubin