Altered trafficking of CD8+ memory T cells after implantation of rapamycin-eluting stents in patients with coronary artery disease

Aim of this study was to investigate the effects of implantation of different coronary drug-eluting stents on trafficking of central (TCM) or effector (TEM) memory T cells in the coronary sinus of patients with coronary artery disease (CAD) undergoing percutaneous coronary revascularization. Thirty-two patients presenting with stable coronary disease and angiographically proven stenosis of left descending coronary artery were randomly assigned to treatment with rapamycin-eluting, paclitaxel-eluting or bare metal stents. Heparinized blood samples were obtained from the coronary sinus either before or 20 min after stent implantation. Mononuclear cells were stained with mAbs specific for CD3, CD4, CD8, CD45R0, and CD27 molecules. Analysis of surface phenotype was performed by four-color flow cytometry and data on both CD4+ and CD8+ TCM and TEM cells were expressed either as absolute cell numbers/μL of blood or as percentages relative to the corresponding total memory T cell populations in the individual patients. We found that the number of CD8+ TEM, as defined by CD3+CD45R0+CD8+CD27− phenotype, was significantly reduced in patients receiving a rapamycin-eluting stent as compared with basal values. Conversely, the number of CD8+ TCM (CD3+CD45R0+CD8+CD27+) was increased in the same treatment group after the revascularization procedure. No changes in the absolute number of CD4+ and CD8+ total (TCM plus TEM) memory T cells before and after the procedure were observed. These findings suggest that rapamycin eluted from medicated coronary stents rapidly induce a redistribution of memory CD8+ T lymphocyte subsets, with a significant decrease of TEM and a corresponding increase of TCM increase circulating within the coronary sinus. This anti-inflammatory effect could partially explain the reduction of coronary in-stent restenosis rate associated with the clinical use of this type of device.