Growth-arrest-specific 6 (GAS6) protein in ARDS patients: determination of plasma levels and influence of PEEP setting.

BACKGROUND: Growth-arrest-specific protein 6 (GAS6) is a vitamin K-dependent protein expressed by endothelial cells and leukocytes participating in cell survival, migration and proliferation and involved in many pathological situations. The aim of our study was to assess its implication in ARDS and its variation according to PEEP setting, considering that different cyclic stresses could alter GAS6 plasma levels. METHODS: Our subjects were enrolled in the ExPress study comparing a minimal alveolar distention (low-PEEP) ventilatory strategy to a maximal alveolar recruitment (high-PEEP) strategy in ARDS. Plasma GAS6, interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) levels were measured at day 0 and day 3 by enzyme-linked immunosorbent assay in blood samples prospectively collected during the study for a subset of 52 subjects included in 8 centers during year 2005. RESULTS: We found that GAS6 plasma level was elevated in the whole population at day 0: median 106 ng/mL IQR 77-139 ng/mL, with significant correlations with IL-8, the Simplified Acute Physiology Score II and the Organ Dysfunction and Infection scores. Statistically significant decreases in GAS6 and IL-8 plasma levels were observed between day 0 and day 3 in the high-PEEP group (P = .02); while there were no differences between day 0 and day 3 in the low-PEEP group. CONCLUSIONS: GAS6 plasma level is elevated in ARDS patients. The high-PEEP strategy is associated with a decrease in GAS6 and IL-8 plasma levels at day 3, without significant differences in day 28 mortality between the 2 groups. (Clinicaltrials.gov NCT00188058).