Serum exosomal miR-122-5p is a new biomarker for both acute coronary syndrome and underlying coronary artery stenosis

Purpose Acute coronary syndrome presents as unstable angina (UA) or acute myocardial infarction (AMI). We explored the use of exosomal miR-122-5p as a biomarker for UA and AMI and determined whether its expression level is positively correlated with the severity of coronary stenosis.Methods This study enrolled 34 patients with AMI, 31 patients with UA, and 22 control subjects. qPCR was used to detect the expression levels of serum exosomal miR-122-5p.Results The expression of serum exosomal miR-122-5p in UA and AMI patients was significantly higher than that in the control group, and expression levels differed between UA and AMI patients. Receiver operating characteristic analysis demonstrated that serum exosomal miR-122-5p might be used as a diagnostic biomarker for AMI and UA. In addition, we also found that serum exosomal miR-122-5p was positively correlated with the severity of coronary artery stenosis for UA patients based on the Gensini score. Serum exosomal miR-122-5p was highly expressed in patients with a coronary artery stenosis severity greater than 80% during acute coronary syndrome.Conclusion Serum exosomal miR-122-5p might be useful as a diagnostic biomarker for AMI and UA, and increased serum exosomal miR-122-5p levels could be useful to predict the severity of coronary lesions.