Circulating MicroRNA-21 is Downregulated in Patients with Metabolic Syndrome.

The microRNA-21 (miR-21) is known to play a major role in cancer progression; however, its function in the cardiovascular system appears to be even more complex and conflicting. To characterize miR-21 expression in the plasma of individuals with or without metabolic syndrome (MetS), 58 MetS cases and 96 non-MetS controls were investigated. Expression levels of miR-21 were significantly decreased in the circulation of MetS subjects (OR=0.52, 95% CI: 0.29-0.92) compared with that of non-MetS subjects. Body mass index (BMI) and the number of MetS components had a negative correlation with the level of miR-21, whereas age was inversely related to the level of miR-21. No significant difference was detected in miR-21 levels between the sexes (P=0.056). MiR-21 might be a negative regulating factor in MetS.