Interleukin-10 blunts the human inflammatory response to lipopolysaccharide without affecting the cardiovascular response.

Abstract

The objective of this study was to assess the efficacy of variations in dose and timing of administration of recombinant human IL-10 (rhIL-10) on inflammatory and cardiovascular responses in a human endotoxemia model of sepsis. The authors conducted a randomized, placebo-controlled, double-blind trial. The study was conducted in a procedure room of an intensive-care unit. The study comprised 24 healthy male volunteers. Interventions consisted of intravenous administration of rhIL-10 at 1, 10, or 25 microg/kg either 2 mins or 2 hrs before Escherichia coli lipopolysaccharide (4 ng/kg) or placebo. The placebo group receiving lipopolysaccharide alone demonstrated significant, time-dependent changes in vital signs, white blood cell counts, inflammatory cytokine/cortisol levels, and hemodynamic/cardiovascular (including echocardiographic) parameters over the duration of the study. rhIL-10, administered immediately before (concurrent) lipopolysaccharide resulted in decreased temperature and heart rate responses as well as decreased serum levels of proinflammatory cytokines (tumor necrosis factor-alpha, IL-6), IL-1 receptor antagonist, cortisol, and total leukocytes/neutrophils compared with lipopolysaccharide alone. Dose-dependent effects were absent. In contrast, rhIL-10 administration 2 hrs before endotoxin augmented the endotoxin-induced IL-beta and IL-1 receptor antagonist response. rhIL-10 failed to modulate major cardiovascular responses (cardiac output, stroke volume index, ejection fraction, peak systolic pressure/end-systolic volume ratio) to endotoxin in both study groups as assessed by echocardiography. Concurrent administration of rhIL-10 suppresses the human inflammatory/stress response but has no effect on the hemodynamic/cardiovascular response to endotoxin. Early administration of rhIL-10 can potentially augment elements of the cytokine inflammatory response to lipopolysaccharide. These findings suggest significant limitations of rhIL-10 as a potential immunomodulatory therapy for sepsis.