Arindam Maitra, Jayashree Shanker, Debabrata Dash, Prathima Arvind, Vijay V. Kakkar p = 0.010 p = 0.017 2.5 n2.0 o i s s rep1.5 x e e n eeg1.0 v i t a l eR0.5 0 p = 0.038 p = 0.357 TLR-2 TLR-4 TLR-9 TLR-2 TLR-4 TLR-9 Control Case Figure 1. Relative gene expression in TLR-2, TLR-4 and TLR-9 between cases and controls before adjusting for conventional risk factors p = 0.672 p = 0.195 p = 0.955 TLR-2 TLR-4 TLR-9 On statins Not on statins Figure 3. Effect of statin usage on fold changes in TLR gene expression in CAD patients adjusting for age, gender, diabetes, hypertension and smoking. There was a significant association of 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. The predictive probability of the TLRs to accurately classify the CAD cases and controls based on the ROC analysis (AUC value) was 0.69 (p < 0.000) (Figure 3) with overall classification of 62.6% of the cohort. A comparison of the TLR gene expression profile between the study participants on statin therapy and those who were not on the lipid-lowering drug revealed that there was no significant difference in the relative expression profile for all the three TLR genes (Figure 3). Discussion Given the high global prevalence of CVD and its co-morbidities, there is an urgent need to identify novel ways of predicting and managing cardio- vascular risk. It is common knowledge that 2.5 n2.0 o i s s rep1.5 x e e n eeg1.0 v i t a l eR0.5 0 1.8 1.6 n1.4 o isse1.2 r xep1.0 e egn0.8 ive0.6 t a leR0.4 0.2 0 784 Arch Med Sci 5, October / 2011 p = 0.596 p = 0.048 Control Case Figure 2. Relative gene expression in TLR-2, TLR-4 and TLR-9 between cases and controls after adjusting for age, gender, hypertension, diabetes and smoking conventional risk factors account for only 50% of the disease prevalence and existing modalities for addressing this risk are primarily through life style interventions and/or through use of the limited choice of medications available in the market today. Based on the clinico-epidemiological and experi- mental studies, there is a growing understanding that infection may play a significant role in the initiation and progression of atherosclerotic disease [20-22]. Therefore, novel therapies such as modulation of the immune system have opened up unique opportunities to redress the growing concern of CVD burden. In this connection, the TLRs play a critical role in bridging the gap between immune response and cardiovascular disease progression. Lessons learnt from knock out mouse models (apoE –/–, double knock outs such as apoE –/– and TLR-4 –/– or apoE –/– and CD14 –/–) have provided strong mechanistic evidence that TLRs are responsible for the exacerbation of atherosclerotic disease [23]. Mechanisms of TLR action are manifold – ability to directly interfere with cholesterol metabolism in the macrophages by serving as a ligand for minimally modified LDL, a proatherogenic and proinflammatory lipoprotein [24], interaction on the endothelial cell surface resulting in the enhanced secretion of IL-18, a potent proinflammatory cytokine [25], and cross reaction between bacterial and human heat shock protein 60 (HSP60) through molecular mimicry. The signalling here is mediated through TLR-2 and/or TLR-4, leading to the activation of NFκB dependent proinflammatory gene targets [26-28] and consequent accumulation of lipids and leukocytes in the atheroma [3]. Pathological changes that occur during the atherosclerotic disease process release endogenous inflammatory molecules and oxidatively modified lipids that serve as ligands that engage the TLRs and activate their expression [29].