CEREBAL ARTERIAL ADVENTITIA AND VASOSPASM

慢性脑血管痉挛是发病率和死亡率的主要原因 蛛网膜下腔出血的患者。血管痉挛的发病机制是 还没有完全理解，但现有的证据表明， 一氧化氮血管舒张功能受损是一个重要的 暴露于自体血液的动脉变窄的潜在机制。 我们推测，血管外膜一氧化氮生物合成的增加， 可能导致血管扩张， 血管痉挛 为了验证这一假设，我们过度表达了重组 血管外膜成纤维细胞内皮型一氧化氮合酶基因 脑动脉的腺病毒介导的基因转移。 该模型 提供了一个独特的机会， 从外膜释放调节血管反应性，以及 作为信号转导途径， eNOS蛋白。 例如，初步调查结果表明，在我们的 模型，假定的血管痉挛介质的血管收缩作用， 内皮素-1逆转为血管舒张。 这种逆转是 这显然是由于内皮素-1诱导的重组eNOS激活 外膜表达蛋白。我们建议研究表达和 重组内皮型一氧化氮合酶基因在脑动脉外膜的作用 免疫组化。eNOS酶活性的测量， 环鸟苷酸的放射免疫测定和体外和体内分析 血管的反应性。“双出血”犬 将使用脑血管痉挛模型来研究 重组eNOS基因对痉挛性动脉血管张力的影响 我们 预期在本申请中提出实验将确定 外膜中eNOS的过度表达是否可以作为一种替代 一氧化氮的来源，以及这种方法是否可以用来恢复 脑动脉壁一氧化氮生物合成。 我们的研究将 还扩大了有关血管生物学的知识基础， 外膜，及其作为转移和表达的靶点的作用， 治疗有益的重组蛋白。

Chronic cerebral vasospasm is a major cause of morbidity and mortality in patients with subarachnoid hemorrhage. Pathogenesis of vasospasm is not completely understood, but existing evidence suggests that impairment of nitric oxide vasodilator function is an important mechanism underlying narrowing of arteries exposed to autologous blood. We hypothesize that increased biosynthesis of nitric oxide in adventitia of cerebral arteries may cause vasodilatation and prevent development of vasospasm. To test this hypothesis, we over-expressed recombinant endothelial nitric oxide synthase (eNOS) gene in adventitial fibroblasts of cerebral arteries by adenoviral-mediated gene transfer. This model provides unique opportunity to characterize the effects of nitric oxide released from adventitia on regulation of vasomotor reactivity, as well as signal transduction pathways coupled to activation of recombinant eNOS protein. For instance, preliminary findings indicate that in our model, vasoconstrictor effect of a putative mediator of vasospasm, endothelin-1, is reversed to vasodilatation. This reversal is apparently due to endothelin-1-induced activation of recombinant eNOS protein expressed in adventitia. We propose to study expression and function of recombinant eNOS gene in adventitia of cerebral arteries by immunohistochemistry,. measurements of eNOS enzymatic activity, radioimmunoassay of cyclic GMP and in vitro and in vivo analysis of vasomotor reactivity of tansduced arteries."Double hemorrhage" canine model of cerebral vasospasm will be used to study effects of the recombinant eNOS gene on vascular tone of spastic arteries. We anticipate that experiments propose in this application will determine whether eNOS over-expression in the adventitia can serve as a substitute source of nitric oxide, and whether this approach can be used to restore nitric oxide biosynthesis in cerebral arterial wall. Our studies will also expand the knowledge base concerning the vascular biology of adventitia, and its role as a target for transfer and expression of therapeutically beneficial recombinant proteins.