The potential role of miR-450a-1-3p in chromium-associated heart rate variability reduction

Chromium (Cr) exposure has been reported to be associated with heart rate variability (HRV) decline, whereas the underlying mechanism remains unknown. In present study, a cross-sectional study was conducted in Chinese urban adults to explore the potential role of microRNAs (miRNAs) in the relationship between urinary chromium and HRV decline. In the discovery stage, 20 Cr-related miRNAs were screened out by high-throughput sequencing. Both generalized linear model and differential expression analysis were conducted and miR-450a-1-3p was chosen for further analyses. Then, the quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to measure the concentration of plasma miR-450a-1-3p and generalized linear model was used to estimate the association between urinary chromium, plasma miR-450a-1-3p and HRV indices and further to explore the potential role of miR-450a-1-3p in chromium-induced HRV reduction. Precisely, a positive association of chromium exposure with plasma miR-450a-1-3p was observed and HRV indices were negatively related to urinary chromium or plasma miR-450a-1-3p concentrations elevating (all P < 0.05). Furthermore, plasma miR-450a-1-3p significantly mediated and affected the relationship between chromium exposure and HRV reduction. Finally, we used KEGG analysis to study the potential pathway of miR-450a-1-3p and inferred the arrhythmogenic right ventricular cardiomyopathy and calcium signaling pathway were involved in the chromium-induced HRV reduction.