Associations between microRNA (miR-21, 126, 155 and 221), albuminuria and heavy metals in Hong Kong Chinese adolescents

Background and aim: Pathogenetic mechanisms underlying albuminuria are not completely understood. Heavy metals might lead to atherosclerosis and kidney damage. miR-21, 126, 155 and 221 regulated endothelial function and might contribute to the development of albuminuria. To date, no clinical trial has explored the relationship between miRNAs, microalbuminuria and heavy metals in human. In this study, we aimed to examine the association between microalbuminuria, miRNAs and heavy metals in adolescents.

Materials and methods: From a cross-sectional, population-recruited study, we identified 60 school children aged 12-19 years with microalbuminuria (defined as spot urine albumin-creatinine ratio >3.5 mg/mmol). We compared the urine heavy metals (arsenic, mercury, cadmium and lead) and miRNAs levels (miR-21,126, 155 and 221) with another 60 age-and sex-matched normoalbuminuric adolescents as control.

Results: Mean age of the study cohort was 15.5±2.1 years. 43% were boys. Among the four miRNAs tested, only miR-21 was associated with microalbuminuria (p=0.02). Urinary arsenic and lead levels had a negative association with both miR-21 and miR-221. No significant association was found between heavy metals examined and microalbuminuria.

Conclusion: The results of our study suggest an association between microalbuminuria, miR-21 and heavy metals (arsenic and lead). This might imply that miR-21 is involved in the pathogenetic mechanisms linking heavy metals exposure and albuminuria.