Shed L-selectin (sCD62L) load in trauma patients

Biomarkers in Pediatric ARDS: Future Directions

Acute respiratory distress syndrome (ARDS) is common among mechanically ventilated children and accompanies up to 30% of all pediatric intensive care unit deaths. Though ARDS diagnosis is based on clinical criteria, biological markers of acute lung damage have been extensively studied in adults and children. Biomarkers of inflammation, alveolar epithelial and capillary endothelial disruption, disordered coagulation, and associated derangements measured in the circulation and other body fluids, such as bronchoalveolar lavage, have improved our understanding of pathobiology of ARDS. The biochemical signature of ARDS has been increasingly well described in adult populations, and this has led to the identification of molecular phenotypes to augment clinical classifications. However, there is a paucity of data from pediatric ARDS (pARDS) patients. Biomarkers and molecular phenotypes have the potential to identify patients at high risk of poor outcomes, and perhaps inform the development of targeted therapies for specific groups of patients. Additionally, because of the lower incidence of and mortality from ARDS in pediatric patients relative to adults and lack of robust clinical predictors of outcome, there is an ongoing interest in biological markers as surrogate outcome measures. The recent definition of pARDS provides additional impetus for the measurement of established and novel biomarkers in future pediatric studies in order to further characterize this disease process. This chapter will review the currently available literature and discuss potential future directions for investigation into biomarkers in ARDS among children.

Longitudinal course and clinical significance of TGF-beta1, sL- and sE-Selectins and sICAM-1 levels during severe acute stress in children

OBJECTIVES

To elucidate the potential role of circulating levels of transforming growth factor-beta1 (TGF-beta1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble L- and sE-Selectins (sL- and sE-Selectins) in children with sepsis, traumatic brain injury (TBI) or acute respiratory distress syndrome (ARDS).

DESIGN AND METHODS

Levels of TGF-beta1, sICAM-1, L- and sE-Selectins were determined using solid-phase sandwich enzyme-linked immunosorbent assay in plasma of 10 patients with sepsis, 10 patients with TBI, 10 patients with ARDS, compared to 10 ventilated controls with chronic illness but not in acute stress, on days 1, 3, 5, 7 and 10.

RESULTS

The highest values of sICAM-1 were observed in patients with TBI (p<0.001) and those of sE-Selectin in patients with sepsis (p=0.0001). Patients in the control group did not show an elevation of sE-Selectin and sICAM-1 levels longitudinally. Increased levels of measured molecules (TGF-beta1, p<0.02, sE-Selectin, p<0.02, sL-Selectin, p=0.06, sICAM-1, p<0.03) were demonstrated among survivors in the sepsis and ARDS groups of patients and were positively correlated with length of stay (p<0.04) and mechanical ventilation (p<0.001).

CONCLUSIONS

A sustained increase of adhesion molecules occurs during acute stress in children which may contribute to morbidity in patients with sepsis (sE-Selectin) or traumatic brain injury (sICAM-1). Suppression of the expected response of sE-Selectins, s-ICAM-1 and TGF-beta1 is associated with poor outcome.

Prognostic Value of an Early Soluble L-Selectin (sCD62L) Assay for Risk Assessment in Blunt Multiple Trauma: A Metaanalysis

Background: After severe trauma, decreased plasma concentrations of the soluble adhesion molecule L-selectin (sCD62L) have been linked to an increased incidence of lung failure and multiorgan dysfunction syndrome (MODS). Individual studies have had conflicting results, however. We examined multiple studies in an attempt to determine whether early sCD62L concentrations are predictive of major complications after severe trauma.

Methods: We performed a systematic review of six electronic databases and a manual search for clinical studies comparing outcomes of multiply injured patients (Injury Severity Score ≥16) depending on their early sCD62L blood concentrations. Because of various outcome definitions, acute lung injury (ALI) and adult respiratory distress syndrome (ARDS) were studied as a composite endpoint. Weighted mean differences (WMDs) in sCD62L concentrations were calculated between individuals with and without complications by fixed- and random-effects models.

Results: Altogether, 3370 citations were identified. Seven prospective studies including 350 patients were eligible for data synthesis. Published data showed the discriminatory features of sCD62L but did not allow for calculation of measures of test accuracy. Three of four studies showed lower early sCD62L concentrations among individuals progressing to ALI and ARDS (WMD = −229 μg/L; 95% confidence interval, −476 to 18 μg/L). No differences in sCD62L concentrations were noted among patients with or without later MODS. Nonsurvivors had significantly lower early sCD62L plasma concentrations (WMD = 121 μg/L; 95% confidence interval, 63–179 μg/L), but little information was available on potential confounders in this group.

Conclusions: Early decreased soluble L-selectin concentrations after multiple trauma may signal an increased likelihood of lung injury and ARDS. The findings of this metaanalysis warrant a large cohort study to develop selectin-based models targeting the risk of inflammatory complications.

The effect of anti-L-selectin (aselizumab) in multiple traumatized patients--results of a phase II clinical trial

OBJECTIVE

The objectives of this study were to evaluate safety (primary) and clinical efficacy (secondary) of the humanized monoclonal anti-L-selectin antibody aselizumab in severely injured patients.

DESIGN

Prospective phase II, parallel group, double-blind, randomized, placebo-controlled clinical trial.

SETTING

Fourteen medical intensive care units or trauma units in level I trauma centers in Belgium, Germany, and Poland.

PATIENTS

Eighty-four patients with a sustained trauma due to a blunt or penetrating injury and a total Injury Severity Scale score of > or =25.

INTERVENTIONS

Patients received either aselizumab at dosages of 0.5, 1, or 2 mg/kg or placebo within 6 hrs of the traumatic event and were followed for 6 wks.

MEASUREMENTS AND MAIN RESULTS

The number of expeditable adverse events increased dose dependently over the aselizumab groups compared with placebo. There were no statistically significant differences between all groups regarding leukopenia and risk of infection. No immunologic response following infusion of aselizumab was noted. The number of patients with multiple organ failure, defined as a median value of the total Goris Multiple Organ Failure score of > or =5 on > or =2 consecutive days within 14 days, was not significantly different for the 0.5 mg/kg, 1 mg/kg, 2 mg/kg, and placebo groups. There were no statistically significant differences in time of mechanical ventilation, length of stay in an intensive care unit, and total duration of hospitalization between treatment groups.

CONCLUSIONS

Aselizumab was associated with a higher rate of infections and leucopenia; however, this difference was not significantly different compared with placebo. For all efficacy variables, aselizumab presented no significant trends but only a few scattered statistically significant differences between groups.