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 不完全理解，但现有证据表明 一氧化氮血管扩张剂功能受损是重要的 暴露在自体血液中的动脉狭窄的机制。 我们假设外膜中一氧化氮的生物合成增加 大脑动脉的闭塞可能会导致血管扩张并阻止发育 血管痉挛的症状。为了验证这一假设，我们过量表达了重组 外膜成纤维细胞内皮型一氧化氮合酶基因的表达 通过腺病毒介导的基因转移来治疗脑血管疾病。这款车 提供了独特的机会来描述一氧化氮的影响 从外膜释放对血管运动反应性的调节 作为信号转导通路偶联激活重组人 ENOS蛋白。例如，初步调查结果表明，在我们的 模型，一种可能的血管痉挛介质的血管收缩作用， 内皮素-1被逆转为血管扩张。这一逆转是 显然是由于内皮素-1诱导的重组eNOS的激活 外膜表达的蛋白质。我们建议研究表达和 重组eNOS基因在脑动脉外膜中的作用 免疫组织化学、。ENOS酶活性的测定， 环状GMP的放射免疫测定及体内外分析 转移性动脉的血管收缩反应性。“二次失血”犬 脑血管痉挛模型将被用于研究脑血管痉挛的作用。 重组eNOS基因对痉挛动脉血管张力的影响。我们 预计本申请中提出实验将确定 ENOS在外膜的过度表达是否可以替代 一氧化氮的来源，以及这种方法是否可以用于恢复 脑动脉壁中一氧化氮的生物合成。我们的研究将 也扩展了关于血管生物学的知识库 外膜及其作为转移和表达靶点的作用 有益于治疗的重组蛋白。

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.