Department of Cardiothoracic Surgery, Jinling Hospital, School of Clinical Medicine, Nanjing University, No. 305 Zhongshan East Road, Nanjing 210002, Jiangsu Province, People's Republic of China.
Clinics (Sao Paulo). 2011;66(5):895-901. doi: 10.1590/s1807-59322011000500029.
The biological functions of transforming growth factor-β signaling that involves Smad proteins have not been previously investigated with respect to coronary artery bypass grafts. The aim of the present study was to observe the immunostaining of proteins that are related to this signaling pathway.
Fifteen remnants of coronary artery bypass grafts, including nine saphenous veins, three radial arteries and three mammary arteries, were collected from 12 patients who were undergoing coronary artery bypass. Hematoxylin and eosin, Masson's trichrome, and immunohistochemical staining of transforming growth factor-β1, type I receptor of transforming growth factor-β, Smad2/3, Smad4, and Smad7 were performed.
The saphenous veins showed more severe intimal degeneration, more severe smooth muscle cell proliferation and more collagen deposition than the arterial grafts, as evidenced by hematoxylin and eosin and Masson's trichrome stainings. Immunohistochemical assays demonstrated that the majority of the transforming growth factor-β1 signaling cytokines were primarily localized in the cytoplasm in the medial layers of all three types of grafts, whereas ectopic transforming growth factor-β1, type I receptor of transforming growth factor-β, and Smad7 overexpressions in the interstices were observed particularly in the saphenous vein and radial arterial grafts.
Enhanced transforming growth factor-β1 signal transduction with medial smooth muscle cell proliferation and ectopic transforming growth factor-β1, the presence of the type I receptor of transforming growth factor-β, and Smad7 overexpressions in the extracellular matrix may provide primary evidence for early or late graft failure.
转化生长因子-β信号转导涉及 Smad 蛋白的生物学功能，以前尚未在冠状动脉旁路移植术中进行过研究。本研究的目的是观察与该信号通路相关的蛋白质的免疫染色。
从 12 例行冠状动脉旁路手术的患者中收集了 15 个冠状动脉旁路移植术的残余物，包括 9 个大隐静脉、3 个桡动脉和 3 个乳内动脉。进行苏木精和伊红、马松三色染色以及转化生长因子-β1、转化生长因子-β1 型受体、Smad2/3、Smad4 和 Smad7 的免疫组织化学染色。
与动脉移植物相比，大隐静脉显示出更严重的内膜退变、更严重的平滑肌细胞增殖和更多的胶原沉积，这一点通过苏木精和伊红及马松三色染色得到证实。免疫组织化学检测显示，大多数转化生长因子-β1 信号细胞因子主要定位于三种移植物中膜层的细胞质中，而在大隐静脉和桡动脉移植物中观察到的异位转化生长因子-β1、转化生长因子-β1 型受体和 Smad7 过表达位于间隙中。
内侧平滑肌细胞增殖和异位转化生长因子-β1、转化生长因子-β1 型受体的存在以及细胞外基质中 Smad7 的过度表达增强了转化生长因子-β1 信号转导，可能为早期或晚期移植物失功提供了初步证据。
