Serum lipopolysaccharide-binding protein concentrations in trauma victims

Background: In low concentrations, lipopolysaccharide-binding protein (LBP), an acute-phase protein recognizing lipopolysaccharide (LPS), catalyzes its transfer to the cellular receptor consisting of CD14 and Toll-like receptor-4. Previous studies have documented increased serum LBP concentrations in patients with sepsis, systemic inflammatory response syndrome (SIRS), or acute pancreatitis and after cardiopulmonary bypass. No prior studies have examined LBP expression in trauma victims. We hypothesized that admission LBP plasma concentrations are predictive of outcome (mortality) in trauma. This study assessed time-dependent changes in serum LBP concentrations in trauma patients soon after injury. Methods: A prospective, single-institution, observational cohort study of 121 adult trauma patients (age ≥17 years) with moderate to severe injury who required hospitalization. The trauma patients were male in 79.6% of the cases and had a mean age of 43.0 ± 20.6 years. The mean injury severity score (ISS) was 23 ± 12, and the crystalloid resuscitation volume given in the first 24 h averaged 6,640 ± 3,729 mL. Informed consent was obtained on admission, and blood samples were drawn on admission and at 24 h postadmission. Prospective data were collected for daily SIRS score, multiple organ dysfunction score (MODS), and sequential organ failure assessment (SOFA) score, complications, and outcomes. Plasma concentrations of LBP were measured by enzyme-linked immunosorbent assay. Results: Sixty patients (48.8% of the study cohort) required emergency surgical intervention and sustained a substantial intraoperative blood loss (mean 1,404 ± 2,757 mL). The hospital mortality rate was 16.3% (20 patients). The mean intensive care unit stay was 8.9 ± 16.4 days, and the hospital stay was 14.8 ± 19.6 days. The patients had a significantly higher serum concentrations of LBP on admission (mean 28.0 ± 25.3 mg/L; range 2-100 mg/L) than did control subjects (mean 6.2 ± 2.1 mg/L; range 1.3-12.8 mg/L; p < 0.01), similar to the plasma concentrations previously reported in septic patients. A significant increase in LBP concentration was noted at 24 h (mean 72.3 ± 45.7 mg/L; range 8-210 mg/L; p < 0.05). The admission LBP concentration was significantly greater in nonsurvivors than in survivors. However, after controlling for age and ISS, the admission LBP concentration did not predict death. Conclusions: In this prospective study of trauma patients, LBP concentrations were significantly increased early post-injury (on admission), and higher concentrations were associated with a higher mortality rate. However, the independent prognostic value of admission LBP was not incremental to clinical outcome predictors (age and ISS) in logistic regression analysis. Additional studies are necessary to determine the peak and nadir LBP concentrations. The serum concentration of LBP in trauma victims soon after injury may have prognostic importance, and further studies are warranted.