Abstract
Major surgery such as coronary artery bypass grafting (CABG) is associated with an increased post-operative risk of atherosclerotic cardiovascular events. Cells of the innate immune system can adopt a long-lasting pro-inflammatory and atherogenic phenotype after brief exposure to exogenous or endogenous inflammatory stimuli, a process called “trained immunity”. We hypothesized that the surgery-induced inflammation leads to sustained alterations in monocyte function, which promote the subsequent occurrence of cardiovascular events. Blood from 13 patients undergoing elective CABG was obtained before, 3–7 days (median 4) after, and 6–8 weeks (median 6) weeks after surgery. At 3–7 days postoperatively, circulating C-reactive protein (CRP) concentration, leukocyte counts and ex vivo Peripheral Blood Mononuclear Cell (PBMC) IL-6, TNFα and IL-1Ra production after stimulation (with various inflammatory stimuli) were significantly increased. Simultaneously, there was a reduction in monocyte HLA-DR expression. 6–8 weeks after CABG there was an ongoing systemic pro-inflammatory state with higher CRP concentrations, increased stimulated ex vivo PBMC IL-6 production, changes in monocytes subsets, and a higher expression of CCR2 on monocytes compared to baseline. In conclusion, CABG induces a persistent systemic inflammatory reaction with a sustained activated monocyte phenotype. This might contribute to the increased atherosclerotic cardiovascular event risk observed in cardiac surgery patients.
Published Version
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