CXCL12 and acute respiratory distress syndrome: In comparison with the ARDS group, the iNO group showed an elevation in the plasma VEGF (256±81.1 vs. 478±63.3 ng/l, p<0.05, respectively) and SDF-1 (4.3±1.3 vs. 6.0±1.2 μg/l, p<0.05, respectively) at 72 h.