Interleukin-37 elevation in patients with atrial fibrillation

BackgroundInflammation is closely related to atrial fibrillation (AF) pathogenesis, and interleukin-37 (IL-37) represents a new member of the anti-inflammatory cytokines. Hypothesis IL-37 might play an important role in AF development and act as a potential risk factor for AF diagnosis. MethodsThe mRNA level of IL-37 in peripheral blood mononuclear cells (PBMCs) and serum IL-37 levels in AF patients and healthy controls were measured by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). PBMCs from AF patients were stimulated with recombinant IL-37. Levels of pro-inflammatory cytokines IL-6 and C-reactive protein were determined by RT-PCR and ELISA. Results IL-37 mRNAs and serum protein levels were higher in patients with AF or lone AF compared with healthy controls. Patients with paroxysmal AF or persistent AF showed higher IL-37 mRNAs and serum protein levels compared with those with permanent AF as well as healthy controls. In vitro, IL-37 inhibited the production of IL-6 and C-reactive protein in PBMCs of patients with AF. Conclusions IL-37 is elevated in AF patients and its expression is closely associated with AF subgroups. Thus, IL-37 may provide a novel research target for the pathogenesis and therapy of AF. This study is the first to document elevated IL-37 in AF patients.