Am. J. Respir. Crit. Care Med.,
Volume 158, Number 1, July 1998, 92-98
Differential Effects of Anti-cytokine Treatment
on Bronchoalveolar Hemostasis in
Endotoxemic Chimpanzees
MARCEL
LEVI,
TOM
van der POLL,
HUGO
ten CATE,
BART
KUIPERS,
BART J.
BIEMOND,
HENK M.
JANSEN,
and
JAN WOUTER
ten CATE
Center for Hemostasis, Thrombosis, Atherosclerosis and Inflammation Research, Laboratory of Experimental Medicine, and Department of
Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
Activation and inhibition of coagulation and fibrinolysis was analyzed in bronchoalveolar lavage
(BAL) fluids obtained from endotoxin-challenged chimpanzees. The mediatory role of tumor necrosis
factor-alpha (TNF-
) and interleukin-6 (IL-6) on endotoxin-induced changes in bronchoalveolar coagulation and fibrinolysis was investigated in experiments in which the infusion of endotoxin was combined with the administration of monoclonal anti-TNF-
or anti-IL-6 antibodies. Endotoxin infusion
elicited a marked increase in bronchoalveolar thrombin generation as measured by levels of prothrombin activation fragment F1+2 and thrombin-antithrombin complexes. Markers for intrinsic
pathway activation were not detectable, suggesting that the thrombin generation was mediated by
the tissue factor-dependent route. Levels of antithrombin were low before the injection of endotoxin
and not detectable hereafter. The administration of anti-IL-6 antibody completely abolished the endotoxin-induced activation of bronchoalveolar coagulation, whereas treatment with anti-TNF-
antibody only partly inhibited this effect. Bronchoalveolar fibrinolytic activity, due to urokinase-type plasminogen activator (u-PA), was significantly depressed after endotoxin injection, mainly due to a
striking increase in plasminogen activator inhibitor-2 levels in BAL fluid. The endotoxin-induced effects on bronchoalveolar fibrinolysis could be blocked by the simultaneous administration of anti-
TNF-
antibodies. We conclude that endotoxemia results in the activation of bronchoalveolar coagulation, which is apparently mediated by the tissue factor route of coagulation activation and which
may be amplified by consumption of antithrombin III. Bronchoalveolar fibrinolytic activity is significantly abolished by increased levels of mainly PAI-2 after the injection of endotoxin. The endotoxin-induced effects on bronchoalveolar coagulation appears to be mediated by IL-6, whereas TNF-
seems to be the pivotal mediator of the endotoxin-induced depression of bronchoalveolar fibrinolysis.