F-18 FDG Pet/CT Can Reflect The Synthetic Vascular Smooth Muscle Cell Activity In The Atherosclerotic Carotid Artery Of Rat

Abstract

Background and Aims: Synthetic vascular smooth muscle cells (VSMCs) have critical functions in vascular remodeling disorders including atherosclerosis, stent-related stenosis, arteriovenous fistula and transplanted organ failure. This study aimed to demonstrate the synthetic VSMC activities in the atherosclerotic carotid artery using F-18 FDG PET/CT.

Methods: Atherosclerosis was induced in Sprague-Dawley rats by partial ligation of the right carotid artery coupled with an atherogenic diet and vitamin D injections (2 consecutive days, 600,000 I.U./day). 28 days later, rats undertook F-18 FDG PET/CT. Harvested vessels were subjected to autoradiography, H&E staining, and immunohistochemistry. Antibodies against α-smooth muscle-actin (α-SMA), smooth muscle myosin heavy chain (SM-MHC), CD68, myeloperoxidase (MPO), collagen type-III, cyclophilin A (CypA), matrix metallopeptidase-9 (MMP-9), and glucose tranporter-1 (GLUT-1) were used.

Results: The atherosclerotic right carotid arteries presented profound luminal narrowing with neointimal hyperplasia. The neointimal hyperplasia areas were made up of α-SMA positive cells with the scanty expressions of SM-MHC. Surrogate markers of synthetic VSMCs such as collagen type III, CypA, and MMP-9 were richly expressed in neointima region. However, neither CD68-immunopositive macrophages nor MPO-immunopositive neutrophils were observed in regions with neointimal hyperplasia. F-18 FDG PET/CT imaging with subsequent autoradiography showed increased FDG tracer uptake into the atherosclerotic carotid artery. Consistently, the expression of GLUT-1 was markedly increased in neointimal hyperplasia area.

Conclusions: F-18 FDG PET/CT is a potentially useful tool for evaluating syntheticVSMC activities in vascular remodeling disorders.