Expression Profiles Of Six Circulating MicroRNAs Critical 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 are involved in atherosclerosis and dyslipidemia as gene regulators.Objective:To determine the expression profiles of six serum miRNAs critical to atherosclerosis in SCH patients and re-analyze the association between atherosclerosis and SCH from a new perspective.Outcomes, Design, and Participants:MicroRNAs 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:Serum TC, LDL-c and TG levels in SCH, SCH+ATH and ATH group were all significantly higher than that in NC group. In addition, Serum TC and LDL-c levels in SCH+ATH group were higher than in SCH group, whereas no differences of serum TC, LDL-c and TG levels were found between the SCH+ATH and ATH subjects.The relative expression of miR-21-5p showed significant up-regulation in SCH (1.842±0.221), SCH+ATH (2.447±0.102) and ATH (1.654±0.171) groups compared with NC (0.912±0.274), respectively, especially in SCH+ATH group. The increased miR-21-5p exceeded in ATH alone and SCH alone groups, respectively. MiR-210showed a slight but not significant stepwise elevation trend from NC (-8.809±0.303) to SCH (-8.337±0.255) then to SCH+ATH (-8.203±0.291) or ATH (-8.164±0.287) group. Both miR-125a-5p and miR-126-3p showed significant stepwise decrease trend from NC (0.053±0.234and1.125±0.211, respectively) to SCH (-0.732±0.206and-0.279±0.247, respectively) then to SCH+ATH (-1.895±0.220and-1.257±0.219, respectively) or ATH (-2.290±0.223and-1.232±0.289, respectively) group. No significant difference was found between the ATH and SCH+ATH subjects. Finally, both miR-221-3p and miR-222-3p were decreased in patients with atherosclerosis including SCH+ATH (-2.466±0.142and-2.636±0.128, respectively) and ATH groups (-2.323±0.197and-2.628±0.208, respectively) than in patients without atherosclerosis including NC (-1.276±0.160and-1.392±0.203, respectively) and SCH alone groups (-1.368±0.110and-1.563±0.125, respectively). No significant differences were found between NC and SCH subjects or between SCH+ATH and ATH group respectively.Spearman’s correlation analysis showed that TSH was positively correlated with TC and LDL-c. TC, TG, and LDL-c were each positively correlated with max-IMT and mean-IMT. With regard to relative expressions of6candidate miRNAs in our study, log2miR-21-5p was positively correlated with TSH and max-IMT, whereas no associations were found between log2miR-21-5p and blood lipid parameters as well as mean-IMT. All the other down-regulated miRNAs (log2miR-125a-5p, log2miR-126-3p, log2miR-221-3p and log2miR-222-3p) were negatively correlated with blood lipids (TC, LDL-c or TG) and CIMT. No correlations between log2miR-210and TSH, lipid profile as well as CIMT were observed. No correlations between6candidate miRNAs and clinical characteristics including age, sex, BMI were found (P>0.05).Hierachical clustering analysis based on the5differentially expressed serum miRNAs could separate a majority of subjects of each group. Sixteen of22NC subjects were clustered together; Fifteen of20SCH alone subjects were clustered together. Sixteen of21SCH+ATH subjects clustered together; Eighteen of22ATH subjects were clustered together.Receiver operating characteristic (ROC) curves were constructed to estimate the sensitivity and specificity of the6candidate serum miRNA for detection of all subclinical hypothyroidism patients and for detection of all atherosclerosis patients from all subjects. The areas under the ROC curves (AUCs) of the6miRNAs are displayed in Fig.4, respectively. MiR-21-5p (Fig.4A) had the largest AUC:0.762(95%CI,0.658-0.865) among the6candidate miRNAs for detection of all subclinical hypothyroidism patients including SCH and SCH+ATH groups from all subjects. MiR-126-3p had the largest AUC:0.888(95%CI,0.819-0.958) among the6candidate miRNAs for detection of all atherosclerosis patients including SCH+ATH and ATH subjects.Conclusions:(1) Serum microRNAs critical to atherosclerosis have abnormal expression and correlated with TC, TG, LDL-C, TSH and CIMT in subclinical hypothyroidism.(2) MiR-21-5p are up regulation both in patients with subclinical hypothyroidism (SCH and SCH+ATH groups) and with atherosclerosis(ATH group), and showed most specific expression patterns in all patients with subclinical hypothyroidism.(3) 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).