Clinical research Understanding the expression of Toll-like receptors in Asian Indians predisposed to coronary artery disease Arindam Maitra1, Jayashree Shanker1, Debabrata Dash1, Prathima Arvind1, Vijay V. Kakkar1,2 1Thrombosis Research Institute, India 2Thrombosis Research Institute, London, United Kingdom Submitted: 5 May 2010 Accepted: 12 July 2010 Arch Med Sci 2011; 7, 5: 781-787 DOI: 10.5114/aoms.2011.25552 Copyright © 2011 Termedia & Banach A b s t r a c t Introduction: Toll-like receptors (TLRs) are an important link between innate and adaptive immunity. Material and methods: Expression of TLR-2, TLR-4, and TLR-9 genes was assessed in 60 coronary artery disease (CAD) patients and 79 controls by SYBR Green 1 based real time PCR assay. Results: Expression of the TLR-2 gene was found to be significantly elevated in cases (1.295 ±0.09) compared to the controls (1.033 ±0.08) (p = 0.015) whereas expression of the TLR-9 gene was significantly lower in cases (1.522 ±0.18) than in the controls (2.165 ±0.16) (p = 0.032). There was no difference in TLR-4 expression levels (p = 0.174). A significant correlation of TLR-2 was observed with TLR-4 (r = 0.803, p < 0.0001) and TLR-9 (r = 0.264, p = 0.003) as well as between TLR-4 and TLR-9 (r = 0.303, p = 0.001). A significant association was seen between TLR 2 (OR 3.94, 95% CI 1.73-8.99, p = 0.001) and TLR-9 (OR 0.297, 95% CI 0.131-0.672, p = 0.004) with CAD after adjustment for age and gender. Statins did not affect TLR gene expression. Conclusions: The TLR-2, TLR-4 and TLR-9 genes exhibit a differential pattern of expression between CAD patients and controls in this Asian Indian cohort. This observation warrants further investigation, keeping in mind the infectious and inflammatory elements in perspective, in order to understand the true implications of TLR in the aetiopathology of CAD and consequent therapeutic implications. Key words: Toll-like receptors, gene expression, coronary artery disease, Asian Indians. Introduction Atherosclerosis is considered to be an immunomodulatory disease, wherein infections by common pathogens and the ensuing inflammatory and immune response mechanisms play a significant role in the regulation of disease progression [1, 2]. Toll-like receptors (TLRs) are a family of pattern recognition receptors that serve as the first line of defence against invading microbes and/or tissue injury [3]. Endothelial cells, macrophages, adventitious fibroblasts and dendritic cells express TLRs in the atherosclerotic vessel wall. Twelve different families of TLRs have been discovered to date, of which TLR-1, TLR-2, TLR-4 and TLR-9 are key receptors implicated in the development and progression of coronary artery disease (CAD) [4, 5]. The TLRs recognize a variety of bacterial and fungal Corresponding author: Dr. Jayashree Shanker Thrombosis Research Institute 258/A, Bommasandra Industrial Area Anekal Taluk Bangalore 560099, India Phone: 91-80-27835303, 91-80-27835302 E-mail: jayashreeshanker@triindia.org.in