Expression Profiles of Six Circulating MicroRNAs Critical to Atherosclerosis in Patients with Subclinical Hypothyroidism: a Clinical Study

Context: Increasing evidence shows that subclinical hypothyroidism (SCH) is associated with atherosclerosis (ATH), but the association remains controversial. MicroRNAs (miRNAs) have been proved to be involved in atherosclerosis and dyslipidemia as gene regulators.

Objective: The objective of the study was to determine the expression profiles of six serum miRNAs critical to atherosclerosis in SCH patients and reanalyze the association between atherosclerosis and SCH from a new perspective. OUTCOMES, DESIGN, AND PARTICIPANTS: MicroRNA profiling analysis was performed by real-time PCR in normal control subjects (NC; n = 22); patients with subclinical hypothyroidism alone (SCH; n = 20); SCH patients plus atherosclerosis (SCH+ATH; n = 21); and patients with atherosclerosis but without subclinical hypothyroidism (ATH; n = 22).

Results: MiR-21-5p was up-regulated in SCH, SCH+ATH, and ATH groups than in the NC group. In addition, expression levels of miR-21-5p in SCH+ATH group were higher than in SCH alone and ATH alone groups, respectively. Both miR-125a-5p and miR-126-3p showed a decreased trend from NC to SCH and then to SCH+ATH or ATH subjects. MiR-221-3p and miR-222-3p were decreased in the SCH+ATH and ATH groups compared with either the NC or SCH groups. No differences were found in the levels of miR125a-5p, miR126-3p, miR221-3p, and miR222-3p between the ATH and SCH+ATH group.

Conclusions: MiR-21-5p showed the most specific expression patterns in all patients with subclinical hypothyroidism (SCH and SCH+ATH groups). Down-regulation of miR-125a-5p, miR-126-3p, miR-221-3p, and miR-222-3p may be a manifestation of atherosclerosis either in SCH+ATH or in ATH-alone patients. MiR-126-3p has the most specific expression patterns in all atherosclerosis patients (SCH+ATH and ATH groups).