CLINICS

Clinics (Sao Paulo). 2011 May; 66(5): 895-901.
doi:10.1590/S1807-59322011000500029

Copyright © 2011 Hospital das Clínicas da FMUSP

Transforming growth factor-β in graft vessels: histology and immunohistochemistry

Shi-Min Yuan I , Yan-Qing Wang II , Yi Shen I , Hua Jing I

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.

Department of Cardiology, The 81 Hospital of Nanjing, No. 34, Biao 34, Yanggongjing, Nanjing 210002, Jiangsu Province, People's Republic of China.

E-mail: dr.jing@163.com Tel.: 0086 2580860075

received December 17, 2010; revised February 7, 2011; accepted February 14, 2011.

Abstract

OBJECTIVES:

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.

METHODS:

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.

RESULTS:

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.

CONCLUSION:

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.

Keywords: Blood Vessels, Coronary Artery Bypass, Immunohistochemistry, Signal Transduction, Transforming Growth Factor-β


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