Interleukin‐37 and Dendritic Cells Treated With Interleukin‐37 Plus Troponin I Ameliorate Cardiac Remodeling After Myocardial Infarction

Background Excessive immune‐mediated inflammatory reactions play a deleterious role in postinfarction ventricular remodeling. Interleukin‐37 ( IL ‐37) emerges as an inhibitor of both innate and adaptive immunity. However, the exact role of IL ‐37 and IL ‐37 plus troponin I (TnI)–treated dendritic cells ( DC s) in ventricular remodeling after myocardial infarction ( MI ) remains elusive. Methods and Results MI was induced by permanent ligation of the left anterior descending artery. Our results showed that treatment with recombinant human IL ‐37 significantly ameliorated ventricular remodeling after MI , as demonstrated by decreased infarct size, better cardiac function, lower mortality, restricted inflammatory responses, decreased myocardial fibrosis, and inhibited cardiomyocyte apoptosis. In vitro, we examined the phenotype of IL ‐37 plus TnI–conditioned DC s of male C57 BL /6 mice and their capacity to influence the number of regulatory T cells. Our results revealed that IL ‐37 plus TnI–conditioned DC s obtained the characteristics of tolerogenic DCs ( tDC s) and expanded the number of regulatory T cells when co‐cultured with splenic CD 4 + T cells. Interestingly, we also found that adoptive transfer of these antigen‐loaded tDC s markedly increased the number of regulatory T cells in the spleen, attenuated the infiltration of inflammatory cells in the infarct hearts, decreased myocardial fibrosis, and improved cardiac function. Conclusions Our results reveal a beneficial role of IL ‐37 or tDC s treated with IL ‐37 plus TnI in post‐ MI remodeling that is possibly mediated by reestablishing a tolerogenic immune response, indicating that IL ‐37 or adoptive transfer of IL ‐37 plus TnI–treated tDC s may be a novel therapeutic strategy for ventricular remodeling after MI.