Everolimus-Eluting Stents Reduce Monocyte Expression of Toll-Like Receptor 4.

Purpose: Toll-like receptors (TLR) are well known components of the innate immune system. Among them, TLR4 is related to the inflammatory processes involved in atherosclerotic plaque formation. Our purpose was to compare the monocytic expression of TLR4 following implantation of drug-eluting (DES) and bare stents (BMS).

Methods: In this study, patients with chronic stable angina undergoing elective percutaneous coronary intervention (PCI) in ShahidMadani Heart Hospital, Tabriz, Iran were included. Ninety-five patients receiving DES and 95 patients receiving BMS were selected between 2012 and 2014.Everolimus eluting stents were implanted for DES group. Both groups received similar medications and procedure. Blood samples were taken before PCI, 2 hours and 4 hours after termination of PCI. Expression of TLR4 on monocytes was measured using flowcytometry. Patients were matched for age, sex and coronary artery disease risk factors, but not for TLR4 expression rate before PCI.

Results: A significant difference was seen between DES and BMS in TLR4 expression before (21.3±2.8% vs. 15.5±2.7%; P< 0.05) and four hours after PCI (30.1 ± 3.3% vs 39.2 ± 3.2%, P< 0.05). Due to the unmatched rate of TLR4+ expression before PCI, we measured the percentage of increase in TLR4 expression between groups. DES compared to BMS significantlycaused less increase in the TLR4 expression (50.23%±10.03% vs. 446.35%±70.58%, p<0.001).

Conclusion: Our findings suggest thateverolimuseluted from the stents can decrease PCI induced increase in the TLR4 expression on the surface of monocytes.