Expression patterns of serum MicroRNAs related to endothelial dysfunction in patients with subclinical hypothyroidism

Abstract

Background: Increasing evidence has shown that elevated Thyroid stimulating hormone (TSH) levels are positively correlated with atherosclerosis (ATH) in patients with subclinical hypothyroidism (SCH). Some researchers found that the dysfunction of Endothelial Cells (ECs) in SCH plays an important role in the pathogenesis of ATH in SCH, but the association remains controversial.

Objectives: To determine the expression profiles of serum microRNAs critical to the function of Endothelial cells (ECs) may help reanalyze the possible mechanism underlying ATH in SCH and the association between ATH and SCH.

Methods: We used qRT-PCR to perform microRNA profiling and analysis in normal control subjects (NC), patients with SCH alone (SCH), patients with SCH and ATH (SCH+ATH), and patients with ATH without SCH (ATH).

Results: Both miR-221-3p and miR-222-3p showed a decreasing expression trend between the SCH and SCH+ATH groups. In addition, miR-126-3p and miR-150-5p showed a stepwise decrease from the NC to SCH groups and then to the SCH+ATH or ATH group. miR-21-5p was unregulated in the SCH, SCH+ATH, and ATH groups. Furthermore, elevated levels of miR-21-5p in SCH+ATH group were higher than SCH and ATH group. No differences were found in the levels of miR-150, miR-126, miR-221 and miR-222 between the ATH and the SCH+ATH subjects.

Conclusions: miR-21-5p may be involved in the atherosclerosis process in patients with SCH (SCH and SCH+ATH groups). miR-150-5p may be sensitive risk markers for predicting endothelial dysfunction in patients with ATH (ATH and SCH+ATH groups).

Keywords: atherosclerosis; circulating microRNAs; differentially expressed miRNAs; endothelial dysfunction; subclinical hypothyroidism.

Figure 1

Flow chart in the study protocol.

Figure 2

(A–G). Multiple comparisons of baseline characteristics among NC, SCH, SCH+ATH and ATH subjects. *P< 0.05, **P< 0.01, ***P< 0.001, ****P< 0.0001, NS means no significance. (H) The six miRNAs and cel-miR-39 served as the spike-in control all showed reliable threshold cycle (Ct) values in all subjects. The horizontal lines indicate the mean. (I) The total RNA concentration among the four group were discovered no differences significantly. NS means no significance.

Figure 3

The relative expression levels of 6 candidate serum miRNAs (shown in log2 scale) among all subjects. Cel-miR-39 is a synthetic C. elegans miR-39 miRNA mimic. The horizontal lines indicate the mean. The dotted lines indicate the zero. P value was generated by one-way ANOVA test followed by the LSD post hoc multiple comparisons test. *P< 0.05, **P< 0.01, ***P< 0.001, ****P< 0.0001, NS means no significance.

Figure 4

The variable parameters of affecting atherosclerosis. The horizontal lines indicate the OR (Odds Ratio). The dotted lines indicate the variable parameter value. P< 0.05 was defined significant. OR, Odds Ratio; 95% CI, 95% confidence interval.

Figure 5

The different expression of five miRNAs could be agglomerated in hierarchical agglomerative clustering analysis.

Figure 6

(A) Roc curves for six circulating miRNAs to distinguish the all SCH patients (SCH+ATH and SCH) from the (NC and ATH) subject. (B) Roc curves for six circulating miRNAs to distinguish the all ATH patients (SCH+ATH and ATH) from the (NC and SCH) subject. AUC, area under curve; CI, confidence interval.