Shears L L, Kibbe M R, Murdock A D, Billiar T R, Lizonova A, Kovesdi I, Watkins S C, Tzeng E
University of Pittsburgh, Department of Surgery, PA 15261, USA.
J Am Coll Surg. 1998 Sep;187(3):295-306. doi: 10.1016/s1072-7515(98)00163-x.
Inadequate nitric oxide (NO) availability may underlie vascular smooth muscle overgrowth that contributes to vascular occlusive diseases including atherosclerosis and restenosis. NO possesses a number of properties that should inhibit this hyperplastic healing response, such as promoting reendothelialization, preventing platelet and leukocyte adherence, and inhibiting cellular proliferation.
We proposed that shortterm but sustained increases in NO synthesis achieved with inducible NO synthase (iNOS) gene transfer at sites of vascular injury would prevent intimal hyperplasia. We constructed an adenoviral vector, AdiNOS, carrying the human iNOS cDNA and used it to express iNOS at sites of arterial injury in vivo.
AdiNOS-treated cultured vascular smooth muscle cells produced up to 100-fold more NO than control cells. In vivo iNOS gene transfer, using low concentrations of AdiNOS (2 x 10(6) plaque forming units [PFU]/rat) to injured rat carotid arteries, resulted in a near complete (>95%) reduction in neointima formation even when followed longterm out to 6 weeks post-injury. This protective effect was reversed by the continuous administration of an iNOS selective inhibitor L-N6-(1-iminoethyl)-lysine. However, iNOS gene transfer did not lead to regression of preestablished neointimal lesions. In an animal model more relevant to human vascular healing, iNOS gene transfer (5 x 10(8) PFU/pig) to injured porcine iliac arteries in vivo was also efficacious, reducing intimal hyperplasia by 51.8%.
These results indicate that shortterm overexpression of the iNOS gene initiated at the time of vascular injury is an effective method of locally increasing NO levels to prevent intimal hyperplasia.
一氧化氮（NO）生成不足可能是血管平滑肌过度生长的原因，而血管平滑肌过度生长会导致包括动脉粥样硬化和再狭窄在内的血管闭塞性疾病。NO具有许多应能抑制这种增生性愈合反应的特性，如促进内皮再形成、防止血小板和白细胞黏附以及抑制细胞增殖。
我们提出，通过在血管损伤部位进行诱导型一氧化氮合酶（iNOS）基因转移实现短期内NO合成的持续增加，可预防内膜增生。我们构建了携带人iNOS cDNA的腺病毒载体AdiNOS，并将其用于在体内动脉损伤部位表达iNOS。
用AdiNOS处理的培养血管平滑肌细胞产生的NO比对照细胞多100倍。在体内，将低浓度的AdiNOS（2×10⁶ 空斑形成单位[PFU]/大鼠）用于损伤的大鼠颈动脉进行iNOS基因转移，即使在损伤后长期观察至6周，也能使新生内膜形成几乎完全减少（>95%）。持续给予iNOS选择性抑制剂L-N⁶-（1-亚氨基乙基）-赖氨酸可逆转这种保护作用。然而，iNOS基因转移并未导致已形成的新生内膜病变消退。在一个与人类血管愈合更相关的动物模型中，在体内将iNOS基因转移（5×10⁸ PFU/猪）至损伤的猪髂动脉也有效，可使内膜增生减少51.8%。
这些结果表明，在血管损伤时启动iNOS基因的短期过表达是局部增加NO水平以预防内膜增生的有效方法。
