Localization of Latent Transforming Growth Factor-β Binding Protein-1 in Human Coronary Atherosclerotic Plaques

Abstract

Background: Transforming growth factor-β (TGFβ) and its receptors have been detected by immunohistochemistry in the normal vessel wall and in atherosclerotic lesions of human coronary arteries. However, TGFβ is normally secreted as an inactive complex associated with a latent TGFβ-binding protein (LTBP). Therefore, detection of TGFβ antigen only in the arterial wall does not imply the activated form of the growth factor. Methods and Results: In situ hybridization and immunohistochemistry demonstrated LTBP1 mRNA and protein expression throughout the media and intima of early coronary artery lesions, with the highest levels of protein at the luminal surface. In advanced lesions, LTBP1 mRNA and protein were detected mainly in regions of high cell density, such as the fibrous cap. Conclusions: Assays of the TGFβ signalling pathway will be required to determine the activity associated with TGFβ antigen in the vessel wall.