Gene Expression Patterns in Peripheral Blood Correlate with the Extent of Coronary Artery Disease Peter R. Sinnaeve 1,3 *, Mark P. Donahue 1 , Peter Grass 2 , David Seo 1 , Jacky Vonderscher 2 , Salah-Dine Chibout 2 , William E. Kraus 1 , Michael Sketch, Jr. 1 , Charlotte Nelson 1 , Geoffrey S. Ginsburg 1 , Pascal J. Goldschmidt-Clermont 1 , Christopher B. Granger 1 1 Duke University Medical Center and Duke Clinical Research Institute, Duke University, Durham, North Carolina, United States of America, 2 Novartis Institute for Biomedical Research, Cambridge, Boston, United States of America, 3 UZ Leuven Gasthuisberg, University of Leuven, Leuven, Belgium Abstract Systemic and local inflammation plays a prominent role in the pathogenesis of atherosclerotic coronary artery disease, but the relationship of whole blood gene expression changes with coronary disease remains unclear. We have investigated whether gene expression patterns in peripheral blood correlate with the severity of coronary disease and whether these patterns correlate with the extent of atherosclerosis in the vascular wall. Patients were selected according to their coronary artery disease index (CADi), a validated angiographical measure of the extent of coronary atherosclerosis that correlates with outcome. RNA was extracted from blood of 120 patients with at least a stenosis greater than 50% (CADi$23) and from 121 controls without evidence of coronary stenosis (CADi = 0). 160 individual genes were found to correlate with CADi (rho.0.2, P,0.003). Prominent differential expression was observed especially in genes involved in cell growth, apoptosis and inflammation. Using these 160 genes, a partial least squares multivariate regression model resulted in a highly predictive model (r 2 = 0.776, P,0.0001). The expression pattern of these 160 genes in aortic tissue also predicted the severity of atherosclerosis in human aortas, showing that peripheral blood gene expression associated with coronary atherosclerosis mirrors gene expression changes in atherosclerotic arteries. In conclusion, the simultaneous expression pattern of 160 genes in whole blood correlates with the severity of coronary artery disease and mirrors expression changes in the atherosclerotic vascular wall. Citation: Sinnaeve PR, Donahue MP, Grass P, Seo D, Vonderscher J, et al. (2009) Gene Expression Patterns in Peripheral Blood Correlate with the Extent of Coronary Artery Disease. PLoS ONE 4(9): e7037. doi:10.1371/journal.pone.0007037 Editor: Pieter H. Reitsma, Leiden University Medical Center, Netherlands Received September 22, 2008; Accepted August 9, 2009; Published September 14, 2009 Copyright: ß 2009 Sinnaeve et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The study was funded by Novartis. Drs Grass, Chibout and Vonderscher are full-time employees of Novartis, and participated in the study design and data collection and analysis, but had no influence in the decision to publish. Competing Interests: Drs Grass, Chibout and Vonderscher are full-time employees of Novartis. * E-mail: peter.sinnaeve@uzleuven.be Introduction Coronary artery disease, a multifactorial chronic disease, is the leading cause of death in Western countries. Despite considerable advances in the prevention and treatment of coronary artery disease and its complications, morbidity and mortality remains high. In half of patients with coronary artery disease, the first manifestation is death [1]. Consequently, substantial efforts are being put into the development of new strategies for accurate noninvasive diagnosis of coronary artery disease and the identification of novel treatment targets [2]. Systemic and local inflammation has been shown to play a prominent pathologic role in atherosclerotic coronary artery disease [3]. Adhesion of leukocytes to activated endothelial cells and their migration into the arterial wall are thought to initiate, propagate, and destabilize coronary plaques. All types of blood constituents appear to play a role in plaque formation, although the majority of inflammatory lesions in atherosclerotic vascular tissue consist of foam cell macrophages and activated T-cells [4]. Several studies have found distinct gene expression patterns in atherosclerotic arteries [5–8]. While other pathways are likely also important, a consistent feature has been differential expression of inflammatory genes and genes involved in cell cycle control [9–12]. Microarray analysis of peripheral blood cells is a practical approach to study gene expression changes that may reflect not only genetic predisposition but also presence and activity of disease, environmental modifier effects, and treatment responses [13]. Total peripheral leukocyte count correlates with the severity of coronary atherosclerosis and is a strong predictor of cardiovascular outcome [14], but little is known about the role of phenotypic changes in circulating blood cells of patients with coronary atherosclerosis. In a recent micro-array analysis, 526 genes were found to be differentially expressed in isolated mononuclear cells from 41 patients [15]. Gene expression patterns of 50 of these genes together with 56 genes selected from the literature were subsequently shown to be associated with the presence of coronary artery disease in two independent cohorts. The aim of the present study was 1) to identify distinct genomic markers in peripheral whole blood that correlate with the severity of coronary artery disease using micro-array analysis and 2) to investigate to what extent gene expression patterns in peripheral blood mirror those in atherosclerotic arteries. PLoS ONE | www.plosone.org 1 September 2009 | Volume 4 | Issue 9 | e7037