Circulating MiR-146a May be a Potential Biomarker of Coronary Heart Disease in Patients with Subclinical Hypothyroidism.

Background/Aims: Subclinical hypothyroidism (SCH) plays a crucial role in the development and progression of coronary heart disease (CHD). However, any associated changes in the circulating microRNAs (miRNAs) levels and slightly elevated thyroid stimulating hormone (TSH) levels in CHD patients are unknown. miR-146a is a well known miRNA associated with inflammatory autoimmune diseases. Here, we evaluated miR-146a expression in patients, with the goal of re-evaluating the effect of SCH on CHD. Methods: A total of 192 study subjects who underwent coronary angiography for either suspected or confirmed CHD were enrolled in 3 groups: CHD with SCH, CHD alone, and healthy controls. The circulating levels of miR146a were quantified using qRT-PCR. Results: Levels of miR-146a were positively correlated with CHD severity, as indicated by the Gensini score (r=0.354). The relative expression of miR-146a in the CHD+SCH, CHD and healthy control groups was 2.223 +/- 0.827, 1.588 +/- 0.726 and 0.632 +/- 0.309, respectively. Plasma TSH levels were positively correlated with miR-146a levels (r=0.321). According to multivariate logistic regression analyses, miR-146a levels were associated with the incidence of CHD in patients with SCH. For diagnosing CHD, the area under the ROC curve (AUC) of miR-146a and TSH was 0.779 and 0.752, respectively. When the TSH and miR-146a levels were combined to form a composite panel, the AUC of the panel was 0.858. Conclusion: Plasma miR-146a levels correlated with the severity of coronary atherosclerosis and increased with TSH slightly elevated in patients with CHD. Thus, miR-146a may have good predictive value for CHD among individuals with elevated TSH levels. (C) 2018 The Author(s) Published by S. Karger AG, Basel