CDP-choline: Mechanisms in Cerebral Ischemia

CDP-胆碱：脑缺血的机制

• 批准号: 6890254
• 负责人: RAO M ADIBHATLA
• 金额: $ 27.65万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6890254
• 关键词: arachidonate; cardiolipins; cerebral ischemia /hypoxia; choline; cytosine nucleotides; enzyme activity; enzyme mechanism; gerbil /jird; glutathione; histopathology; immunocytochemistry; pharmacokinetics; phosphatidylcholines; phosphodiesterases; phospholipase A2; phospholipids; reperfusion; sphingomyelin phosphodiesterase; sphingomyelins; spontaneous hypertensive rat; western blottings

DESCRIPTION (provided by applicant): Significance and goal: CDP-choline (citicoline) stroke clinical trials in Europe and Japan showed significant improvement, while US studies provided ambiguous results. The route of administration (oral in USA vs iv in non-USA) and 24-hr time window may have hindered its effectiveness in the USA trials. It has now been realized that oral administration in USA trials was inappropriate and new Phase III trials will soon be undertaken. Our studies show that CDP-choline treatment delayed by 3-hr did not offer any neuroprotection. CDP-choline mode of action has not been clearly identified, and understanding its mechanism(s) should lead to more effective treatment of ischemic brain injury. The efficacy of CDP-choline in stroke therapy might still be achieved. Rationale: Phospholipid degradation is a significant promoter of neuronal death after transient cerebral ischemia. CDP-choline neuroprotection is thought to be due to increased phosphatidyl-choline (PtdCho) synthesis in the injured brain, although the evidence is limited. We showed in gerbil transient forebrain ischemia that CDP-choline: (a) provided significant neuroprotection (b) significantly restored PtdCho, cardioliPin and sphingomyelin, (c) attenuated arachidonic acid release and metabolism, and (d) increased glutathione levels. Our preliminary results show that CDP-choline affects activation of membrane and mitochondrial phospholipase A2 (PLA2) that is raM-Ca 2+ dependent (characteristic of secretory PLA2; sPLA2), supporting the hypothesis and Aim 1. In vitro, CDP-choline and its components (cytidine and choline) did not inhibit PLA2 activity, and thus as such CDP-choline is not a "direct PLA2 inhibitor". Instead CDP-choline in vivo likely affects PLA2 activation. Hypothesis: CDP-choline attenuates phospholipid hydrolysis by preventing activation of PLA2. To test this hypothesis in transient cerebral ischemia, we propose the following specific aims: Aim 1: Determine whether CDP-choline inhibits PLA2 activation and protein expression. Since this aim is central to our hypothesis, it will be tested both in gerbil transient forebrain ischemia and transient focal cerebral ischemia of spontaneously hypertensive rat. Aim 2: Determine whether CDP-choline alters cytidine triphosphate phosphocholine cytidylyltransferase (PCCT) and sphingomyelinase activities mediated through PLA2. PCCT makes endogenous CDP-choline and is the rate-limiting enzyme in PtdCho synthesis. Exogenous CDP-choline is hydrolyzed, absorbed as cytidine and choline, and has to be re-synthesized by PCCT. PtdCho hydrolysis by PLA2 results in lyso-PtdCho and arachidonic acid. Lyso-PtdCho inhibits PCCT activity resulting in impaired PtdCho synthesis. Arachidonic acid activates neutral sphingomyelinase, resulting in membrane disintegration. PCCT activity was stimulated by exogenous CDP-choline. Aim 2 will be tested in gerbil transient forebrain ischemia.

描述（由申请人提供）：重要性和目标：欧洲和日本的CDP-胆碱（Citicoline）中风临床试验显示出显着改善，而美国的研究则提供了模棱两可的结果。给药途径（美国的口头与非美国的IV）和24小时的时间窗口可能会阻碍其在美国试验中的有效性。现在已经意识到，美国试验中的口头管理是不适当的，新的III期试验将很快进行。我们的研究表明，3小时延迟的CDP-胆碱治疗没有提供任何神经保护。 CDP-胆碱的作用方式尚未清楚地识别出来，了解其机制应导致对缺血性脑损伤的更有效治疗。 CDP-胆碱在中风疗法中的功效仍然可以实现。 理由：磷脂降解是瞬时脑缺血后神经元死亡的重要启动子。 CDP-胆碱神经保护被认为是由于受伤的大脑中磷脂酰胆碱（PTDCHO）的增加引起的，尽管证据是有限的。我们在沙鼠短暂的前脑缺血中表明，CDP-胆碱：（a）提供了显着的神经保护（b）显着恢复了PTDCHO，Cardiolipin和Sphingomyelin，（c）减弱的花生四烯酸释放和代谢，以及（d）增加了粘液性水平。我们的初步结果表明，CDP-胆碱会影响膜和线粒体磷脂酶A2（PLA2）的激活，而RAM-CA 2+（分泌PLA2; SPLA2的特征）（spla2; spla2的特征）支持假设并瞄准1. inter，cdp-胆碱和其成分（CDP-胆碱和芯片），以及cytide（cytiD），以及cytine and cytidine and cytine and in Cytine and Cytine（cytidine and Cytide），intive in Cytine and cytine and in Cytif in Cytine（ CDP-胆碱不是“直接PLA2抑制剂”。相反，体内CDP-胆碱可能会影响PLA2激活。 假设：CDP-胆碱通过预防PLA2的激活来减轻磷脂水解。为了检验瞬态脑缺血中的这一假设，我们提出以下特定目的：目标1：确定CDP-胆碱是否抑制PLA2激活和蛋白质表达。由于此目的是我们假设的核心，因此将在Gerbil瞬态前脑缺血和瞬态局灶性脑缺血中进行测试。 AIM 2：确定CDP-胆碱是否会改变三磷酸磷酸磷酸化胆碱细胞替糖苷转移酶（PCCT）和通过PLA2介导的鞘磷脂酶活性。 PCCT生产内源性CDP-胆碱，是PTDCHO合成中的速率限制酶。外源CDP-胆碱被水解，吸收为胞苷和胆碱，必须通过PCCT重新合成。 PLA2通过PTDCHO水解导致溶血-ptdcho和蛛网膜酸。 Lyso-Ptdcho抑制PCCT活性，导致PTDCHO合成受损。蛛网膜酸激活中性鞘磷脂酶，从而导致膜分解。外源CDP-胆碱刺激PCCT活性。 AIM 2将在Gerbil瞬态前脑缺血中进行测试。