MOLECULAR BASIS OF THE PLATELET STORAGE LESION

血小板的收集和体外储存导致 磷脂酰丝氨酸（PS）的进行性运动， 磷脂酰乙醇胺（PE）从内到外小叶的 血小板质膜 这种正常质膜的丧失 磷脂（PL）不对称性与这些氨基磷脂的暴露 在血小板表面上，与凝血酶的形成有关， 补体激活，以及肝脾隔离， 输血后血小板的加速清除。 这个项目 旨在确定导致这种异常的机制 贮藏中质膜磷脂的跨双层运动 血小板，并推导出将保持正常的储存条件， 将PS和PE隔离到内小叶。 具体目标 包括：（1）判断PS的渐进运动是否与 在自体血浆中储存期间血小板的表面反映 通过机械剪切诱导的膜重组， 血小板质膜氨基磷脂转位酶的活性， 和/或血小板质膜的不适当活化 （2）确定磷脂酶的相对贡献， 改变细胞内Ca 2+、ATP和pH值，加速跨双层 血小板膜磷脂的运动;（3）为了确定如何 PL扰码酶或氨基磷脂的氧化变化 在细胞储存过程中的易位酶影响跨双层分布 （4）确定血浆中磷脂的作用 血小板浓缩物中所含的成分， 氨基磷脂向血小板表面的移动。 特别 感兴趣的是凝血酶，纤溶酶和C5 b-9组分的作用， 补充;（5）确定优化的储存条件，以保持 血小板质膜氨基磷脂的正常隔离。 这些条件被认为是最佳的，最大化的活动， 氨基磷脂移位酶和最小化的细胞内的 Ca 2+激活的PL扰码酶。

Collection and in vitro storage of blood platelets results in the progressive movement of phosphatidylserine (PS) and phosphatidylethanolamine (PE) from inner to outer leaflet of the platelet plasma membrane. This loss of normal plasma membrane phospholipid (PL) asymmetry with exposure of these aminophospholipids on the platelet surface is implicated in the formation of thrombin, in the activation of complement, and in hepato-splenic sequestration and accelerated clearance of platelets following transfusion. This Project aims to identify the mechanism(s) responsible for this abnormal transbilayer movement of plasma membrane phospholipids in stored platelets and to deduce conditions of storage that will preserve normal sequestration of PS and PE to the inner leaflet. The Specific Aims include: (1) To determine whether the progressive movement of PS to the surface of platelets during storage in autologous plasma reflects membrane reorganization induced through mechanical shear, a decrease in activity of the platelet plasma membrane aminophospholipid translocase, and/or inappropriate activation of the platelet plasma membrane phospholipid scramblase; (2) To determine the relative contributions of altered cytosolic Ca2+, ATP, and pH to the accelerated transbilayer movement of platelet plasma membrane phospholipids; (3) To determine how oxidative changes in either PL scramblase or aminophospholipid translocase during cell storage affect transbilayer distribution of plasma membrane phospholipids; (4) To determine the role of plasma components contained in platelet concentrates to the accelerated movement of aminophospholipids to the platelet surface. Of particular interest is the role of thrombin, plasmin and the C5b-9 components of complement; (5) To identify storage conditions optimized to maintain the normal sequestration of platelet plasma membrane aminophospholipids. Those conditions are considered optimal that maximize the activity of aminophospholipid traslocase and minimize that of the intracellular Ca2+-activated PL scramblase.