Prognostic value of Toll-like receptor 4 on human monocyte subsets combined with computed tomography-adapted Leaman score assessing coronary artery disease

Abstract

Background Upregulation of Toll-like receptor 4 (TLR-4) is associated with coronary plaque vulnerability assessed by coronary computed tomography angiography (CCTA). Computed tomography-adapted Leaman score (CT-LeSc) is an independent long-term predictor of cardiac events. The relationship between the TLR-4 expression of CD14++CD16+ monocytes and future cardiac events is unknown. We investigated this relationship using CT-LeSc in patients with coronary artery disease (CAD). Methods We analyzed 61 patients with CAD who underwent CCTA. Three monocyte subsets (CD14++CD16−, CD14++CD16+, and CD14+CD16+) and the expression of TLR-4 were measured by flow cytometry. We divided the patients into two groups according to the best cutoff value of the TLR-4 expression on CD14+CD16+ which could predict future cardiac events. Results CT-LeSc was significantly greater in the high TLR-4 group than the low TLR-4 group [9.61 (6.70–13.67) vs. 6.34 (4.27–9.09), P < 0.01]. The expression of TLR-4 on CD14++CD16+ monocytes was significantly correlated with CT-LeSc (R 2 = 0.13, P < 0.01). The expression of TLR-4 on CD14++CD16+ monocytes was significantly higher in patients who had future cardiac events than in those who did not [6.8 (4.5–9.1) % vs. 4.2 (2.4–7.6) %, P = 0.04]. High TLR-4 expression on CD14++CD16+ monocytes was an independent predictor for future cardiac events (P = 0.01). Conclusion An increase in the TLR-4 expression on CD14++CD16+ monocytes is related to the development of future cardiac events.