The Association between Inflammatory Cytokines and miRNAs with Slow Coronary Flow Phenomenon

Slow coronary flow (SCF) is a coronary artery disorder. Several inflammatory mediators have been reported to be associated with vascular homeostasis and endothelial dysfunction. The aim of this study was to investigate the association between cytokines and miRNAs in patients with SCF compared to the controls. In this regard, blood samples were acquired from 45 SCF patients and 45 age- and sex-matched healthy control subjects. Serum and peripheral blood mononuclear cells (PBMCs) were separated. Expression levels of miRNAs and cytokines in PBMCs were measured by real-time PCR. As a final point, serum levels of cytokines were quantified by ELISA. Expression levels of miR-1, miR-133, miR-208a, miR-206, miR-17, miR-29, miR-223, miR-326, and miR-155 as considerable indicators of inflammatory function significantly increased in SCF patients while the expression levels of miR-15a, miR-21, miR-25, miR-126, miR-17, miR-16 and miR- 18a as considerable indicators of anti-inflammatory function significantly decreased in patients with SCF compared to the control group. Additionally, serum IL-1β, IL‐8, and TNF-α concentrations were significantly higher in the SCF group than controls. However, no significant differences were observed in IL-10 production in SCF patients compared to the controls. This study provided the potential role of miRNAs as biomarkers for SCF diagnosis as well as suitable markers for monitoring coronary artery disease (CAD) development in these patients. More investigations are still necessary to unravel the detailed essential mechanisms of circulating miRNA levels in patients with heart failure and SCF.