Decreased circulatory microRNA-4478 as a specific biomarker for diagnosing non-ST-segment elevation myocardial infarction (NSTEMI) and its association with soluble leptin receptor.

Objective: This study aimed to assess the usefulness of circulatory microRNA-4478 (miR-4478) and soluble leptin receptor (sLEPR) in prognosis and diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) and to introduce miR-4478 as a new biomarker for NSTEMI disease. This study aimed also to examine correlation between miR-4478 and soluble leptin receptor and effects of miR-4478 on leptin receptor concentration.

Background: MicroRNAs could be used as predictive biomarkers for diseases.

Methods: We collected sera of 80 angiographically confirmed NSTEMI patients and 80 healthy individuals and performed RNA extraction, cDNA synthesis, measurement of microRNAs, sLEPR and other chemistries. Statistical analyses were done using excel, XLSAT, and SPSS. Quality control analysis was done triplicated for 7 serial dilution of stock cDNA solution.

Results: The patients with NSTEMI had higher serum levels of miR-4478, sLEPR, cTnI, CKMB, Urea, creatinine, glucose, cholesterol, TG, and ALP but lower levels of ALT compared with the normal healthy individuals. We detected decrease in expression of miR-4478 (2^-∆∆Cq = 0.161 ± 0.211) along with increase in sLEPR levels (F = 3.645, p < 0.001) in the NSTEMI group compared with normal individuals. Pearson's correlation tests indicated positive correlation of miR-4478 and sLEPR (p < 0.001, R² = 0.698). There was sensitivity and specificity of 87.5% and 98.8% for miR-4478 and 92.5% and 87.5% for sLEPR.

Conclusion: Circulatory miR-4478 and sLEPR may be used as predictors of NSTEMI. miR-4478 may also be used as a new biomarker for NSTEMI disease (Tab. 3, Fig. 6, Ref. 30).