Expression of toll like receptors 4 in patients with different types of coronary artery disease and its correlation with risk factors of in-stent restenosis after percutaneous coronary intervention

Objective To analyze the expression of toll like receptors 4 (TLR4) in patients with different types of coronary artery disease (CAD), and to explore association between TLR4 and in-stent restenosis (ISR) after percutaneous coronary intervention (PCI). Methods A total of 342 patients who underwent coronary angiography (CAG) because of chest pain were enrolled. According to the angiographic results, patients were divided into control group (n=44) and coronary artery disease (CAD) group (n=298), including 48 cases with stable angina pectoris (SAP) and 250 cases with acute coronary syndrome (ACS). TLR4 level was compared between SAP group and ACS group. All the ACS patients were further divided into unstable angina (UA) group (n=68), non-ST-segment elevation myocardial infarction (NSTEMI) group (n=85) and ST-segment elevation myocardial infarction (STEMI) group (n=97). TLR4 levels were compared between the three groups. Outcome was set as ISR after PCI during follow up. The influence factors were analyzed between intra-stent restenosis (ISR) group and non-ISR group. And the association between TLR4 and ISR was explored. Results There were significant differences in gender, age, course of disease, smoking history, hypertension, glucose, triglycerides (TG), and low density lipoprotein cholesterol (LDL-C) between control group and CAD group (all P<0.05). Compared with SAP group, TLR4 level was significantly increased in ACS group [(137.88±12.43)ng/ml vs. (97.34±9.78)ng/ml, t=2.35, P=0.02]. The TLR4 levels in NSTEMI group and STEMI group were (147.78±15.32)ng/ml and (152.12±13.77)ng/ml, respectively, which were significantly higher than those in UA group [(112.37±11.38)ng/ml, t=2.23, P=0.03; t=2.74, P<0.01]. A total of 18 patients had ISR after PCI, and the ISR rate was 11.4%. TLR4 level in ISR group was significantly higher than in non-ISR group [(149.94±11.43)ng/ml vs. (95.45±10.78)ng/ml, t=7.13, P<0.01]. Logistic analysis indicated that glucose higher than 11.1 mmol/L (OR=2.67, 95%CI: 1.22-3.93, P=0.022), post-operative smoking (OR=8.65, 95%CI: 4.39-14.71, P=0.020), post-operative aspirin termination more than 1 year (OR=10.12, 95%CI: 6.34-16.28, P=0.016), and LDL-C higher than 4.14 mmol/L (OR=19.35, 95%CI: 13.46-28.39, P=0.005) were risk factors for ISR after PCI. TLR4 was positively correlated with glucose, aspirin termination and LDL-C (r=0.685, P=0.02; r=0.557, P=0.03; r=0.473, P=0.04). Conclusions TLR4 level is higher in ACS patients than in SAP patients. Glucose higher than 11.1 mmol/L, post-operative smoking, post-operative aspirin termination more than 1 year and LDL-C higher than 4.14 mmol/L may be the risk factors for ISR after PCI. Glucose, aspirin termination, and LDL-C are positively correlated with TLR4. Key words: Toll-like receptor 4; Coronary artery disease; Angioplasty, transluminal, percutaneous coronary; Risk factors