Elevated IL-37 levels in the plasma of patients with severe coronary arterycalcification

Background Coronary artery calcification （CAC） is a predictor of cardiovascular events and plaque burden and is closely associatedwith chronic inflammation. Intedeukin （IL）-37 is a newly discovered member of the IL-1 family and is considered an anti-inflammatorycytokine. Our recent study on mice indicated that IL-37 could attenuate atherosclerosis and vascular calcification, which suggests that IL-37could be associated with the development of atherosclerosis and related diseases. The aim of this study was to investigate if IL-37 plays arole in the progression of CAC in patients. Methods Two hundred participants with suspected cardiovascular disease were recruited. Thelevels of plasma IL-37, osteoprotegerin （OPG）, hypersensitive C-reactive protein （hsCRP） together with other biochemical parameters weremeasured, and a coronary calcium assessment was carried out by multi-detector row CT. A score of 〈 10 AU （Agatston units） denotes anabsence of CAC, a score of 11-100 AU denotes mild CAC, 101-400 denotes moderate CAC, and 〉 400 AU denotes severe CAC. ResultsOur initial data showed that there were no apparent differences in plasma IL-37 levels among patients with or without mild or moderate CAC.However, IL-37 levels were significantly increased in patients with severe CAC （P 〈 0.001）. Similar results were observed for plasma OPGand hsCRP levels. When IL-37 levels in patients with severe calcification were compared with that in all of the other non-severe CAC groups,it became apparent that there was a significant positive correlation between IL-37 level and severe CAC （r = 0.360, P 〈 0.001; OR = 1.033）using Spearrnan＇s correlation and binary logistic regression analysis. Conclusions This study demonstrates that the anti-inflammatory cy-tokine IL-37 is associated with high coronary calcium levels, suggesting that IL-37 expression may be caused by the activation ofinf/amma-tion and that IL-37 might become a predictor of severe CAC in the future, which requires further investigation.