Novel Insights of Secretory Phospholipase A₂ Action in Cardiology

Phospholipase A₂s (PLA₂s) produce free fatty acid and lysophospholipid from membrane phospholipid, and these products can be converted into various types of proinflammatory lipid mediators by specific enzymes. Among several types of PLA₂, secretory PLA₂s (sPLA₂s) have crucial roles in the development of cardiovascular diseases. Circulating sPLA₂ is increasing in patients with coronary artery disease (CAD), and it can be a risk factor for CAD and a prognostic factor in those patients. Secretory PLA₂s amplify the inflammatory responses in myocardial ischemia/reperfusion injury and fetal acute respiratory distress. In some animal experiments, sPLA₂s can hydrolyze low-density lipoprotein and high-density lipoprotein and lead to progress of atherosclerotic plaques. Some inhibitor studies for sPLA₂ revealed that inhibition of sPLA₂ reduced the myocardial impairment after ischemia/reperfusion injury and progression of atherosclerotic plaque areas in animal models. Secretory PLA₂s might be a new target for cardiovascular medicine.