Acquirement of the Ischemic Cardioprotection and ecto-5'-nucleotidase : Investigation of the Receptor Activation and Subsequent Signal Transduction

我们已经完成了ecto-5‘-核苷酸酶高表达小鼠的制备。缺血30min再灌流2小时的在体模型脑梗塞面积(24%)明显小于对照组(49%)。在缺血期早期，胞外5‘-核苷酸酶被迅速激活，导致腺苷产量增加。在健康的Beagle犬模型中，缺血预适应可显著缩小缺血90分钟和再灌流6小时所提供的心肌梗死面积，这一作用可被1)PKC抑制，2)胞外5‘-核苷酸酶抑制，3)腺苷A1受体阻断和4)p38MAPK抑制，或被肌膜或线粒体KATP通道阻断部分减弱。此外，抑制p70S6激酶可取消第二窗口…缺血预适应48小时后更具保护作用。这些数据表明即时和第二窗口预适应保护心肌的机制不同。现在我们正在建立犬cDNA微阵列系统，该系统可以同时分析多达10000个基因表达模式的变化。在这个过程中，我们准备了一个试点系统，可以一次分析100个已知的mRNA。使用该系统，我们测试了3小时低流量缺血对100mRNA表达模式的影响，发现其中约15种mRNA发生了显著变化。在临床上，我们正在进行一些开放或双盲随机病例对照多中心试验，在伦理委员会的批准下，检查ATP衍生物、KATP通道开放剂和人HAMP衍生物对急性心肌梗死的影响(Coat和J-Wind研究)和潘生丁对稳定的轻度慢性心力衰竭的影响(ROAD研究)。COAT研究现在显示，使用ATP衍生物的急性期治疗在1年后结果更好。有趣的是，现在的ROAD研究表明，双嘧达莫的慢性治疗导致ADL增加，血浆BNP和醛固酮水平下降。这些研究现在正在进一步进行，以期得出最终结果。较少

We had completed in preparing the ecto-5'-nucleotidase overexpression mice. The infarct size in the in vivo model afforded by 30-min ischemia and 2-hour reperfusion was significantly smaller (24 %) than that in the control (49 %). The ecto-5'-nucleotidase was rapidly activated early in the ischemic phase, which resulted in the increase in adenosine production. We also examined using these mice the changes in mRNA expression pattern by micro-array system, which revealed that adenosine in the ischemic phase plays cardioprotective roles.In healthy beagle dog model, ischemic preconditioning caused marked reduction in infarct size afforded by 90-min ischemia and 6-hour reperfusion, which was blunted by 1)PKC inhibition, 2) ecto-5'-nucleotidase inhibition, 3)adenosine A1 receptor blockade and 4)p38MAPK inhibition during preconditioning period, or partially attenuated by either sarcolemmal or mitochondrial KATP channel blockade. Furthermore, p70S6 kinase inhibition abolished the second-window … More protection after 48 hours of the preconditioning ischemia. These data indicate that the immediate and second-window preconditioning protect myocardium by different mechanisms.Now we are establishing the cDNA micro-array system in dogs, which can analyze the changes in as much as 10000 mRNA expression patterns at once. On this process, we prepared a pilot system that can analyze 100 known mRNA at once. Using this system, we tested the effect of 3-hour low flow ischemia on the 100 mRNA expression patterns and found that about 15 kinds of mRNA among them showed significant changes.In clinical settings, we are now operating some open or double-blind randomized case-control multi-center trials to examine the effect of an ATP derivative, a KATP channel opener, and a human hAMP derivative on acute myocardial infarction (COAT and J-WIND studies) and the effect of dipyridamol on stable mild chronic heart failure (ROAD study), under the approval of the ethical committee. COAT study now revealed that the acute phase treatment with ATP derivative resulted in better outcome 1-year later. Interestingly, ROAD study now showed that the chronic treatment with dipyridamol resulted in the increase in ADL, reduction in plasma BNP and aldosterone levels. These studies are now going on further toward the final results. Less