TFF2 and acute respiratory distress syndrome: Respiratory epithelium markers include surfactant proteins (SP); Krebs von den Lungen-6 (KL-6) protein, vascular endothelial growth factor (VEGF) and soluble receptor for advanced glycation end-products (sRAGE)Surfactant proteins (SP) are generally increased in ARDS, and SP-B can cross damaged alveolocapillary membranes [16, 17].