ACTA ENDOCRINOLOGICA (BUC)

Context. MicroRNAs (miRNAs) are short noncoding RNAs involved in posttranscriptional regulation of gene expression that influence various cellular functions including glucose and lipid metabolism and adipocyte differentiation. Objective. The aim of this study was to evaluate the levels of miR-34a and miR-149 and their relationship with metabolic parameters in obese children and adolescents. Design. Seventy children and adolescents were enrolled in the study. Plasma levels of microRNAs were evaluated by real-time PCR using SYBR green and analyzed by ΔCt method. Plasma concentrations of visfatin and insulin were measured by ELISA method. Glucose and lipid profile were determined colorimetrically. HOMA-IR was calculated and used as an index of insulin resistance (IR). Results. miR-34a was significantly lower in subjects with insulin resistance compared to obese children with normal insulin sensitivity. There was an inverse relationship between miR-34a levels and both insulin and HOMA-IR. On the other hand, miR-149 was significantly correlated with visfatin. There was no significant difference in miR-34a and miR-149 between obese and normal weight subjects. Conclusions. miR-34a is associated with insulin and HOMA-IR and thus seems to be involved in IR. miR- 149 is inversely associated with visfatin levels which could be indicative of anti-inflammatory effect of this miRNA.