Whether Circulating miRNAs or miRNA-Carriers Serve as Biomarkers for Acute Myocardial Infarction

Circulating MicroRNA-145 is Associated with Acute Myocardial Infarction and Heart Failure

Background:

Recent studies show that microRNA-145 (miRNA-145) might be an attractive tumor biomarker of considerable prognostic value, but little is known about their relationship with acute myocardial infarction (AMI). This study investigated the correlation between the level of miR-145 and AMI.

Methods:

One-hundred patients were divided into three groups: no coronary artery disease (CAD) group, non-ST segment elevation myocardial infarction group, and ST segment elevation myocardial infarction group. The plasma levels of miR-145 were quantified using real-time quantitative polymerase chain reaction. Logarithmic transformation of miRNA-145 levels (Ln_miRNA-145) was used for statistical analysis due to the skewed data distribution.

Results:

Plasma levels of miR-145 were significantly lower in patients with AMI compared to patients in the non-CAD group (−6.38 ± 0.11 vs. −4.47 ± 0.17, P < 0.0001). Compared to those without heart failure, the levels of miR-145 were significantly lower in patients with heart failure (−6.91 ± 0.20 vs. −5.35 ± 0.13, P < 0.0001). We also found that the lower plasma levels of miRNA-145 significantly correlated with increased serum levels of B-type natriuretic peptide (Spearman ρ= −0.60, P < 0.0001), troponin T (Spearman ρ= −0.62, P < 0.0001), and decreased ejection fraction (Spearman ρ= 0.65, P < 0.0001). In a multivariable linear regression analysis, AMI and heart failure were independently associated with lower Ln_miRNA-145 (estimate −0.99, standard error [SE] 0.28; P = 0.001 and estimate −0.62, SE 0.21; P = 0.004).

Conclusions:

Our results suggest that decreased plasma levels of miR-145 are associated with AMI. Circulating miR-145 may be useful in prognosticating cardiac function and the risk of developing heart failure.

miR-103 Regulates Oxidative Stress by Targeting the BCL2/Adenovirus E1B 19 kDa Interacting Protein 3 in HUVECs

Oxidative stress plays a critical role in cardiovascular diseases. Salidroside, a glycoside from Rhodiola rosea, has been used as an antioxidative therapy for oxidative injury in cardiac diseases. However, the mechanism underlying its antioxidant effect needs to be elucidated. Treatment of HUVECs with H₂O₂ significantly decreased the expression of miR-103 in a dose- and time-dependent manner, whereas pretreatment with salidroside significantly inhibited this decrease. Subsequent analysis showed that overexpression of miR-103 abrogated cell activity and ROS production induced by H₂O₂. Bcl2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) was determined to be a novel miR-103 target in HUVECs. Interestingly, H₂O₂ treatment upregulated BNIP3 expression; in turn, this effect was inhibited by pretreatment with salidroside. Further studies confirmed that the knockdown of BNIP3 enhanced cell activity and suppressed the ROS production induced by H₂O₂. These results demonstrated for the first time that salidroside protects HUVECs in part by upregulating the expression of miR-103, which mediates BNIP3 downregulation and plays an important role in the cytoprotective actions.