MicroRNAs Modulation and Clinical Outcomes at 1 Year of Follow-Up After Excision of Subcutaneous Abdominal Fat in Overweight Patients with Pre-Diabetes Treated with Metformin vs. Placebo

Background: obese pre-diabetics have altered expression of cytokines, and sirtuin-1, that might influence myocardial function via microRNAs (miRs) expression. Objectives: to evaluate inflammatory/oxidative stress, miRs’ expression and cardiovascular function in obese pre-diabetics randomly assigned to metformin therapy vs. placebo vs. normo-glycemics at 12 months of follow-up. Materials and methods: eighty-three obese patients enrolled for abdominoplastic surgery, were divided in pre-diabetics (n 55), normo-glycemics (n 28), and assigned to hypocaloric diet. Pre-diabetics were randomly assigned to metformin (n 23) or to placebo (n 22) plus hypocaloric diet. Results: at enrollment, pre-diabetics obese vs. normo-glycemic presented higher values of glucose, insulin resistance (HOMA-IR), inflammatory/oxidative stress markers, miR-195 and miR-27, and lower values of sirtuin-1 (p<0.05). At 12 months of follow up, obese pre-diabetics with metformin vs. placebo experienced significant reduction of glucose values, HOMA-IR, and inflammatory/oxidative stress markers, with significant reduction of intima-media thickness (IMT), septum and posterior wall thickness, and left ventricle mass (LVM), (p <0.05). At 12 months of follow-up, obese pre-diabetics with placebo vs. normo-glycemics had higher values of inflammatory/oxidative stress markers, higher values of IMT, septum and posterior wall thickness, LVM, and myocardial performance index (MPI), (p<0.05). Obese pre-diabetics in metformin vs. placebo, and obese pre-diabetics with placebo vs. normoglycemics, had significant differences about IMT, MPI, and LVM (p<0.05). Obese pre-diabetics in metformin vs. placebo showed significant reduction of serum miR-195 and miR-27 (p<0.05). Obese pre-diabetics in metformin vs. normoglycemics showed higher expression of serum miR-195 and miR-27 ( p<0.05). Finally, we found inverse relation between IMT and insulin (R -0.351), HOMA-IR (R -0.340), miR-195 (R -0.355), miR-27 (R -0.181); between LVEF and Insulin (R -0.332), HOMA-IR (R -0.142), miR-195 (R -0.297) and miR-27 (R -0.163). We found inverse correlation between LVM and sirtuin-1 (R -0.272), Insulin (R -0.810), HOMA-IR (R-0.183), miR-195 (R -0.446) and miR-27 (R-0.433), and direct correlation with interleukin-6 (R 0.195). MPI inversely linked to miR-195 (R -0.260) and miR-27 (R -0.591). Conclusion: in obese pre-diabetics metformin therapy significantly reduces inflammation/oxidative stress, circulating miR-195 and miR-27, causing reduction of LVM, IMT and amelioration of cardiac performance.