434-P: Possible Mechanisms of Cardioprotective Effects of Metformin in Patients with Type 2 Diabetes and Chronic Heart Failure

Background and Aims: Metformin (MET) treatment in patients with type 2 diabetes (T2D) and chronic heart failure (HF) is associated with better cardiovascular outcomes. Possible mechanism of cardioprotective effect of metformin may be a reduction of dicarbonyl and oxidative stress. In particular, a reduction of methylglyoxal levels (MG). The aim of our study was to evaluate the effect of MET on cardiac structure, cardiac function and exercise capacity in patients with T2D and HF. Materials and Methods: A randomized, double-blind, placebo-controlled, crossover study in a total time of six months testing the effect of 3- month usage of MET (2 g/day) vs. placebo. A group of 44 treatment naive patients with T2D and HF were included. At the beginning and at the end of each intervention period various metabolic tests were done including echocardiography, spiroergometry, and parameters of dicarbonyl stress like MG, Glutathione (GSH), glutathione disulfide (GSSG), and the activity of Glyoxalase1 (GLO-1). Results: MET treatment led to a decrease in HbA1c levels (∆ MET vs. placebo: -3.39 ± 5.33mmol/mol, p = 0.00007), and fasting plasma glucose levels (∆MET vs. placebo: -0.381 ± 1.1mmol/l; p = 0.00145). MET had no effect on oxygen consumption at the maximum tolerated load during spiroergometry (VOmax) (∆MET vs. placebo: -0.142 ± 1.18ml/kg/min; p = 0.64). MET did not affect left ventricular ejection fraction (∆MET vs. placebo: -0.789 ± 6.32%; p = 0.53). The levels of MG didn’t change after MET (∆ MET vs. placebo: 0.0306 ± 0.13nmol/ml; p = 0.19). The activity of GLO-1 was not affected too (∆ MET vs. placebo: 0.0073 ± 0.017 mmol/min/mg Hb; p = 0.22). Conclusion: MET treatment is safe in patients with severe heart failure. Our results do not support the evidence that one of the cardioprotective pathways of metformin is through reducing dicarbonyl stress. Disclosure E. Hošková: None. J. Kopecky: None. J. Veleba: None. H. Malinska: None. K. Velebova: None. V. Melenovsky: None. T. Pelikanova: None. Funding Institute for Clinical and Experimental Medicine 00023001)