Delayed administration of human inter-alpha inhibitor proteins reduces mortality in sepsis.

OBJECTIVE: We have recently shown that administration of human inter-alpha inhibitor proteins (IalphaIp) very early after the onset of sepsis maintains cardiovascular stability and reduced mortality. However, it remains unknown whether injection of IalphaIp at later time points of sepsis has any beneficial effects. We therefore hypothesized that IalphaIp and its active component bikunin are reduced in sepsis and that the delayed administration of IalphaIp also improves survival rate. DESIGN: : Prospective, controlled, and randomized animal study. SETTING: A research institute laboratory. SUBJECTS: : Male adult Sprague-Dawley rats. INTERVENTIONS: Rats were subjected either to polymicrobial sepsis by cecal ligation and puncture (CLP) or to sham operation followed by the administration of normal saline solution (i.e., fluid resuscitation). MEASUREMENTS AND MAIN RESULTS: : Bikunin gene expression in the liver was measured by reverse transcription polymerase chain reaction. Plasma concentrations of IalphaIp were determined by Western blot at 5 and 20 hrs after CLP. IalphaIp clearance was assessed by injecting radioactive IalphaIp at 12 hrs post-CLP, and the half-life was determined. In addition, IalphaIp (30 mg/kg of body weight) or vehicle was administered at 1, 5, or 10 hrs (single treatment) or at both 10 and 20 hrs (double treatment) post-CLP. The necrotic cecum was excised at 20 hrs post-CLP, and 10-day survival was recorded. The results indicate that bikunin gene expression decreased significantly at 20 hrs post-CLP. Moreover, IalphaIp concentrations decreased significantly at 5 and 20 hrs post-CLP, and its half-life increased from 5.6 +/- 0.3 hrs to 11.8 +/- 2.7 hrs (p <.05), suggesting down-regulation of IalphaIp in sepsis despite the decreased clearance. Administration of IalphaIp at 1 hr post-CLP improved the survival rate from 50% to 92% (p <.05), whereas there was no significant improvement when IalphaIp was administrated at 5 or 10 hrs post-CLP. However, double injection of IalphaIp at 10 and 20 hrs post-CLP (i.e., severe sepsis) increased the survival rate from 44% to 81% (p <.05). CONCLUSION: Since delayed but repeated administration of human IalphaIp improves survival after CLP, this compound appears to be a useful agent for the treatment of severe sepsis.

Correlation between mortality and the levels of inter-alpha inhibitors in the plasma of patients with severe sepsis.

Inter-alpha inhibitor protein (IalphaIp) is an endogenous serine protease inhibitor in human plasma. Circulating IalphaIp levels were lower in 51 patients with severe sepsis than in healthy volunteers. Mean levels were 688+/-295 mg/L in patients with severe sepsis who survived (n=32), 486+/-193 mg/L in patients with sepsis who died (n=19), and 872+/-234 mg/L in control subjects (n=25). IalphaIp levels were lower in patients with shock versus those without (540+/-246 [n=33] vs. 746+/-290 [n=18] mg/L; P=.0102). IalphaIp levels were inversely correlated with 28-day mortality rates and Acute Physiology and Chronic Health Evaluation II scores and directly correlated with antithrombin III, protein C, and protein S levels. The administration of IalphaIp (30 mg/kg body weight intravenously) increased the 50% lethal dose in mice by 100-fold after an intravenous challenge of Escherichia coli. Thus, human IalphaIp may be a useful predictive marker and potential therapeutic agent in sepsis.