TLR-4+ peripheral blood monocytes and cardiovascular events in patients with chronic kidney disease-a prospective follow-up study

Background. Atherosclerosis is an inflammatory process mediated by circulating immune cells, including monocytes. There is accumulating evidence for the involvement of Toll-like receptor 4 (TLR-4) as a mediator of atherogenesis. Methods. We evaluated the association between CD14+/TLR-4+ monocytes in peripheral blood (flow cytometry) and future cardiovascular events (CVE), e. g. myocardial infarction, percutaneous transluminal coronary angioplasty (including stenting), aortocoronary bypass, stroke and angiographically verified stenosis of peripheral arteries and cardiovascular (CV) death, in 191 patients with chronic kidney disease Stage V receiving hemodialysis therapy. Results. At baseline, CD14+/TLR-4+ monocytes correlated significantly with age (r = 0.2; P = 0.007), high-sensitivity C-reactive protein (r = 0.2; P = 0.008) and mean arterial pressure (r = -0.2; P = 0.02), but not with gender (P = 0.5), smoking (P = 0.6) and the presence of diabetes (P = 0.5). During a median follow-up period of 36 [1-54] months, 79 (41%) patients experienced a CVE. A total of 55 patients died during the follow-up period, 25 of those due to a confirmed CV cause. Log-rank test did not reveal statistical significance for TLR-4+ monocytes concerning incident CVE (P = 0.3), CV death (P = 0.85) and overall death (P = 0.8). In a multiple Cox-regression analysis, we identified age (P = 0.003) and smoking (P = 0.001) as the only independent variables associated with incident CVE. Conclusions. Unexpectedly, we could not detect an association between CD14+/TLR-4+ monocytes and incident CVE as well as CV death in stable hemodialysis patients. Further studies have to clarify the potential role of this cell population for CV outcome in this population.