A role for phospholipase A2 in ARDS pathogenesis.

Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury that is characterized by arterial hypoxemia and noncardiogenic pulmonary oedema. One feature of ARDS is an alteration of pulmonary surfactant that increases surface tension at the air-liquid interface and results in alveolar collapse and the impairment of gas exchange. Type-II secretory phospholipase A2 (sPLA2-II) plays a major role in the hydrolysis of surfactant phospholipids and its expression is inhibited by surfactant. Here, we discuss the evidence that in pathological situations, such as ARDS, in which surfactant is altered, sPLA2-II production is exacerbated, leading to further surfactant alteration and the establishment of a vicious cycle.