Laboratory of Biochemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.
Curr Pharm Des. 2011 Nov;17(33):3656-61. doi: 10.2174/138161211798220936.
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a calcium-independent phospholipase A2 that circulates in plasma in association with lipoprotein particles, whereas in atherosclerotic plaques it is co-localized with macrophages. Lp-PLA2 generates two proinflammatory mediators, lysophosphatidylcholine and oxidized nonesterified fatty acids, which play a role in the development of atherosclerotic lesions and formation of a necrotic core, leading to more vulnerable plaques. Epidemiologic studies demonstrate that increased circulating levels of Lp-PLA2 predict an increased risk of myocardial infarction, stroke and cardiovascular mortality. Furthermore, histologic examination of diseased human coronary arteries reveals intense presence of the enzyme in atherosclerotic plaques that are prone to rupture. These considerations suggest Lp-PLA2 as a promising therapeutic target in cardiovascular disease. Plasma levels of Lp-PLA2 are increased in various types of hyperlipidemias, while hypolipidemic drugs reduce plasma Lp-PLA2 activity and mass along with the improvement of plasma lipid profile. A selective inhibitor of Lp-PLA2 activity, darapladib, has been developed and studies in animal models and humans have shown that it effectively and safely reduces Lp-PLA2 activity in plasma and in atherosclerotic plaques. Furthermore, in animal models darapladib decreases plaque area and necrotic core area whereas in humans it prevents the expansion of necrotic core volume. Whether the results obtained from the use of darapladib in studies in vitro, as well as in preclinical and clinical studies would translate into benefits on cardiovascular event outcomes, awaits to be proved in 2 ongoing phase 3 trials.
脂蛋白相关磷脂酶 A2(Lp-PLA2)是一种钙非依赖性磷脂酶 A2,与脂蛋白颗粒一起在血浆中循环,而在动脉粥样硬化斑块中与巨噬细胞共存。Lp-PLA2 生成两种促炎介质,溶血磷脂酰胆碱和氧化非酯化脂肪酸,它们在动脉粥样硬化病变的发展和坏死核心的形成中发挥作用,导致更脆弱的斑块。 流行病学研究表明,循环 Lp-PLA2 水平升高预示着心肌梗死、中风和心血管死亡率增加的风险增加。此外,对患病人类冠状动脉的组织学检查显示,在易破裂的动脉粥样硬化斑块中存在强烈的酶活性。这些考虑表明 Lp-PLA2 是心血管疾病有前途的治疗靶点。 各种类型的高脂血症会增加血浆 Lp-PLA2 水平,而降脂药物可降低血浆 Lp-PLA2 活性和质量,并改善血脂谱。Lp-PLA2 活性的选择性抑制剂 darapladib 已被开发出来,动物模型和人类的研究表明,它可有效和安全地降低血浆和动脉粥样硬化斑块中的 Lp-PLA2 活性。此外,在动物模型中,darapladib 可减少斑块面积和坏死核心面积,而在人类中可防止坏死核心体积的扩大。在体外研究、临床前和临床研究中使用 darapladib 获得的结果是否会转化为心血管事件结局的益处,尚有待在 2 项正在进行的 3 期试验中得到证明。