Modulation of phosphatidylinositol 3-kinase signaling reduces intimal hyperplasia in aortocoronary saphenous vein grafts
Modulation of phosphatidylinositol 3-kinase signaling reduces intimal hyperplasia in aortocoronary saphenous vein grafts
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DOI：
10.1016/j.jtcvs.2004.11.048
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发表时间：
2005-06-01
影响因子：
6
通讯作者：
Milano, CA
中科院分区：
文献类型：
--
作者：
Hata, JA;Petrofski, JA;Milano, CA
目标：50% 的人类主动脉冠状动脉隐静脉移植物在 10 年后发生闭塞。内膜增生是移植物闭塞的第一步，由血管平滑肌细胞增殖组成。磷脂酰肌醇 3-激酶及其下游调节剂肌醇 3-磷酸酶 PTEN（10 号染色体上删除的磷酸酶和张力蛋白同源物）是血管平滑肌细胞增殖、迁移和细胞死亡的重要调节剂。本研究测试主动脉冠状动脉隐静脉移植物中PTEN的过度表达是否可以减少内膜增生。方法：成年犬利用自体隐静脉对左前降支进行主动脉冠状动脉搭桥术。用磷酸盐缓冲盐水 (n = 9)、空腺病毒 (n = 8) 或编码 PTEN 的腺病毒 (n = 8) 处理大隐静脉移植物。 30 和 90 天时的动脉造影评估了隐静脉移植物的通畅性。一个子集接受了用标记物转基因（β-半乳糖苷酶，n = 3）、空腺病毒（n = 4）或编码 PTEN 的腺病毒（n = 4）处理的隐静脉移植物，并在术后第 3 天处死以确认表达。从感染编码PTEN的腺病毒的犬隐静脉中分离血管平滑肌细胞，并进行免疫印迹和增殖实验。结果：通过免疫组化、免疫印迹和聚合酶链反应证实大隐静脉移植物转基因表达。动脉造影显示所有隐静脉移植物均已通畅。与用空腺病毒和磷酸盐缓冲盐水处理的相比，用编码 PTEN 的腺病毒处理的大隐静脉移植物显示出内膜面积减少（1.39 +/- 0.11 vs 2.35 +/- 0.3 和 2.57 +/- 0.4 mm(2)，p < .05），并且用编码 PTEN 的腺病毒处理的大隐静脉移植物的内膜/中膜比率较低（0.50 +/- 0.05 与 1.43 +/- 0.18 和 1.11 +/- 0. 14，P < .005）。血管平滑肌细胞中 PTEN 的过度表达抑制血小板衍生生长因子诱导的 Akt 磷酸化，Akt 是磷脂酰肌醇 3-激酶的下游效应子。 PTEN 处理的血管平滑肌细胞表现出基础增殖、血小板衍生生长因子刺激增殖和血清刺激增殖的减少。结论：本研究表明，主动脉冠状隐静脉移植物中 PTEN 过度表达可减少内膜增生。这种血管平滑肌细胞抗增殖作用的机制可能是由于通过 Akt 抑制磷脂酰肌醇 3-激酶信号传导，从而导致血管平滑肌细胞生长和存活率下降。因此，通过 PTEN 过表达调节磷脂酰肌醇 3-激酶途径可能代表一种预防冠状动脉旁路移植术后隐静脉移植物内膜增生的新疗法。
Objectives: Fifty percent of human aortocoronary saphenous vein grafts are occluded after 10 years. Intimal hyperplasia is an initial step in graft occlusion and consists of vascular smooth muscle cell proliferation. Phosphatidylinositol 3-kinase and its downstream regulator, the inositol 3-phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome 10), are important regulators of vascular smooth muscle cell proliferation, migration, and cell death. This study tests whether overexpression of PTEN in aortocoronary saphenous vein grafts can reduce intimal hyperplasia.Methods: Adult dogs underwent aortocoronary bypass grafting to the left anterior descending artery by using the autologous saphenous vein. Saphenous vein grafts were treated with phosphate-buffered saline (n = 9), empty adenovirus (n = 8), or adenovirus encoding for PTEN (n = 8). Arteriography at 30 and 90 days assessed saphenous vein graft patency. A subset received saphenous vein grafts treated with a marker transgene (beta-galactosidase, n = 3), empty adenovirus (n = 4), or adenovirus encoding for PTEN (n = 4) and were killed on postoperative day 3 to confirm expression. Vascular smooth muscle cells were isolated from canine saphenous vein infected with adenovirus encoding for PTEN, and immunoblotting and proliferation assays were performed.Results: Saphenous vein graft transgene expression was confirmed by means of immunohistochemistry, immunoblotting, and polymerase chain reaction. Arteriograms revealed all saphenous vein grafts to be patent. Saphenous vein grafts treated with adenovirus encoding for PTEN demonstrated reduced intimal area compared with those treated with empty adenovirus and phosphate-buffered saline (1.39 +/- 0.11 vs 2.35 +/- 0.3 and 2.57 +/- 0.4 mm(2), p < .05), and the intima/media ratio was lower in saphenous vein grafts treated with adenovirus encoding for PTEN (0.50 +/- 0.05 vs 1.43 +/- 0.18 and 1.11 +/- 0. 14, P < .005). PTEN overexpression in vascular smooth muscle cells inhibited platelet-derived growth factor-induced phosphorylation of Akt, a downstream effector of phosphatidylinositol 3-kinase. PTEN-treated vascular smooth muscle cells demonstrated decreased basal, platelet-derived growth factor-stimulated, and serum-stimulated proliferation.Conclusion: This study demonstrates that PTEN overexpression in aortocoronary saphenous vein grafts reduces intimal hyperplasia. The mechanism of this antiproliferative effect in vascular smooth muscle cells is likely due to inhibition of phosphatidylinositol 3-kinase signaling through Akt, with resultant decreases in vascular smooth muscle cell growth and survival. Therefore modulation of the phosphatidylinositol 3-kinase pathway through PTEN overexpression might represent a novel therapy to prevent saphenous vein graft intimal hyperplasia after coronary artery bypass grafting.