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Infect. Immun., Jun 1997, 2136-2144, Vol 65, No. 6
M Thiel, K Holzer, U Kreimeier, S Moritz, K Peter and K Messmer
Endotoxin-activated polymorphonuclear leukocytes (PMNL) adhere to the
vascular endothelium and cause damage by the release of toxic superoxide
anions (O2-). Because adenosine is a potent inhibitor of PMNL in vitro, the
present study investigates the effects of this nucleoside on the functions
of circulating PMNL in a standardized porcine model of hyperdynamic
endotoxemia. Ten anesthesized pigs received an intravenous (i.v.) 330-min
infusion of endotoxin (5 microg/kg of body weight per h). Another 10 pigs
were also infused with endotoxin plus adenosine (150 microg/kg/min [i.v.]);
this treatment was begun 30 min prior to the beginning of endotoxin
treatment. Control groups (five animals per group) received either
adenosine or physiological saline. Infusion of endotoxin caused severe
neutropenia, shedding of L-selectin, upregulation of beta2-integrins,
increased binding of C3-coated zymosan particles, and subsequent
phagocytosis by PMNL. While phagocytosis-induced production of oxygen
radicals appeared to decrease, extracellular release of superoxide anions
was strongly enhanced. Infusion of adenosine during endotoxemia had no
effect on neutropenia, expression of adhesion molecules, C3-induced
adhesion, phagocytosis, or intracellular production of oxygen radicals,
whereas extracellular release of O2- was strongly inhibited. Thus, i.v.
infusion of adenosine during endotoxemia could be useful in protecting from
O2(-)-mediated tissue injury without compromising the bactericidal
mechanisms of PMNL.
Copyright © 1997, American Society for Microbiology
Effects of adenosine on the functions of circulating polymorphonuclear leukocytes during hyperdynamic endotoxemia
Institute for Surgical Research and Department of Anesthesiology, Klinikum Grosshadern, Ludwig-Maximilians-University Munich, Germany.
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