Correlation of circulating miRNA-33a and miRNA-122 with lipid metabolism among Egyptian patients with metabolic syndrome

BACKGROUND: Metabolic syndrome is defined as a group of interrelated biochemical, clinical, and metabolic factors that directly increase the risk of cardiovascular disease, obesity, and type 2 diabetes mellitus. MicroRNA-33a (miR-33a) and MicroRNA-122 (miR-122) play a crucial role in various biological processes by regulating the gene expression level through post-transcriptional mechanisms, and alterations of their levels are associated with lipid and glucose metabolic disorders. In the present study, we aimed to investigate the correlation of miR-33a and miR-122 with obesity indices and glycemic parameters in a cohort of Egyptian patients. Quantitative real-time polymerase chain reaction (RT-PCR) using TaqMan assay was carried out to estimate the expression levels of miR-33a and miR-122 in serum samples of 100 patients diagnosed as having metabolic syndrome and 50 healthy controls. All patients (100%) had type 2 diabetes (by both history and laboratory assessment) and 70% were obese (BMI ≥ 30 kg/m(2)). RESULTS: Compared to controls, patients had significantly higher serum expression level of miR-33a (p value < 0.001) and miR-122 (p value = 0.0016). miR-33a was less expressed (downregulation expression) with 0.8 fold change in the patient group (obese and diabetic) compared to healthy controls, while miR-122 was highly expressed (upregulation expression) in the patient group of patients with 1.9 fold change. Clinical parameters as body mass index (BMI), wrist circumference (Wc), weight (Wt), and height (Ht) (all p < 0.001); total cholesterol (TC) (p = 0.0115); and triglyceride (TG) (p = 0.0286), all were significantly higher in patients compared to the healthy group. Both miRNAs show statistically significant correlations with clinical and biochemical parameters (p < 0.001). CONCLUSIONS: Circulating miR-33a and miR-122 might be convincing as possible biomarkers for the diagnosis of metabolic syndrome.