Response by Borges et al to Editorial Regarding Article, "Role of Adiponectin in Coronary Heart Disease Risk: A Mendelian Randomization Study"

Causal Relationship between Adiponectin and Diabetic Retinopathy: A Mendelian Randomization Study in an Asian Population

Adiponectin (APN) is suggested to be a potential biomarker for predicting diabetic retinopathy (DR) risk, but the association between APN and DR has been inconsistent in observational studies. We used a Mendelian randomization (MR) analysis to evaluate if circulating APN levels result in DR. We applied three different genetic risk scores (GRS): GRS_All combined all 47 single nucleotide polymorphisms (SNPs), which from a genome-wide association study (GWAS) database-catalog reach significance level; GRS_Limited comprised 16 GRS_All-SNPs with a rigorous threshold (p < 5.0 × 10^-8 for GWAS), and GRS_APN combined 5 SNPs significantly associated with APN level. The MR-inverse-variance weighted method analysis showed that for each 1-SD increase in genetically induced increase in plasma APN, the OR of having DR was β = 0.20 (95% CI: -0.46-0.85, p = 0.553) for GRS_APN, 0.61 (95% CI: 0.10-1.13, p = 0.020) for GRS_All, and 0.57 (95% CI: -0.06 to 1.20, p = 0.078) for GRS_Limited. Sensitivity analysis, including MR-egger regression and the weighted-median approach, did not provide evidence of the pleiotropic effect of IVs. Limited evidence for the causal role of APN in DR risk among Taiwanese diabetic patients was shown based on MR analysis in the present study.

MicroRNA-7b attenuates ischemia/reperfusion-induced H9C2 cardiomyocyte apoptosis via the hypoxia inducible factor-1/p-p38 pathway

OBJECTIVE

MicroRNAs (miRNAs) have been shown to play crucial roles in the occurrence, development, and treatment of many cardiovascular diseases. Coronary heart disease (CAD)-related miRNAs are still a growing research area. miR-7b was reported to be downregulated in acute myocardial infarction (AMI) myocardium tissues. However, it remains largely unknown whether miR-7b is involved in the pathogenesis and progression of the AMI ischemia/reperfusion (I/R) injury.

METHODS

Male C57BL/6 J mice and H9C2 cells were used as models in this study. Masson staining, real-time polymerase chain reaction, Western blot analysis, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling immunofluorescence staining assays were performed to detect the related indicators in the study. SPSS 17.0 software was used to calculate the experimental data.

RESULTS

The results showed that miR-7b expression is downregulated after I/R in mice, and miR-7b could inhibit apoptosis in I/R-induced H9C2 cells via upregulating hypoxia-inducible factor 1a (HIF1a). The inhibitory effect of miR-7b on I/R-induced apoptosis in H9C2 cells was blocked by HIF1a silencing. In addition, our data suggested that the p-P38 pathway may be involved in the role of miR-7 in I/R-induced H9C2 cell apoptosis.

CONCLUSION

We confirmed that the overexpression of miR-7b inhibits I/R-induced apoptosis in H9C2 cells by targeting the HIF1a/p-P38 pathway. Our findings not only demonstrate the potential role of miR-7b in attenuating I/R-induced apoptosis but also provide a new insight into the better prevention of the I/R injury by mediating HIF-1 and p-P38.