P6295Methotrexate reduces cardiac remodeling and improves left ventricle function in rats with Takotsubo cardiomyopathy

Abstract Introduction Takotsubo cardiomyopathy (TC) is characterized by cardiac disfunction and left ventricle (LV) remodeling caused, mainly, by physical or emotional stress. Previously, we have shown in atherosclerotic rabbits that methotrexate (MTX), an anti-inflammatory chemotherapeutic agent, is capable of reducing the inflammatory process and atherosclerotic lesions. Purpose To investigate the effect of MTX treatment in rats with TC. Methods TC was induced in Wistar rats with 2 injections of isoproterenol (85mg/kg) with a 24h interval. Animals were allocated in 3 experimental groups: CT: animals induced and treated with saline; TK: animal induced with isoproterenol and treated with saline; TK-MTX: animals induced with isoproterenol and treated with MTX (1mg/kg). Animals were treated every week for 4 weeks. After the treatment, echocardiography, morphometry and molecular analysis (Western blot) of the LV were performed. Results TK and TK-MTX groups did not show cardiac dilation or LV intraventricular septum and posterior wall thickening. However, compared to TK, the treatment with MTX improved both LV systolic and diastolic function. In addition, the treatment diminished myocytes diameter and subendocardial and interstitial fibrosis of the LV. Protein expression of pro-apoptotic factors (caspase 3 and BAX), pro-inflammatory cytokine TNF-α, metalloproteinase 2, transforming growth factor beta, collagen I and III and hypoxia-inducible factor 2 alfa were all decreased. Vascular endothelial growth factor (VEGF) and adenosine A1 receptor showed increased protein expression in TK-MTX group when compared to CT and TK. There was correlation of myocardial fibrosis (r2=-0.57), myocytes diameter (r2=-0.78) and VEGF expression (r2=0.58) with LV systolic disfunction. Also, myocardial fibrosis (r2=0.57) and VEGF expression (r2=-0.68) correlated with diastolic disfunction in the LV. Animals treated with MTX did not present any toxicity. Conclusion Treatment with MTX diminished apoptosis, the expression of TNF-α and metalloproteinases, cardiac hypertrophy and myocardial fibrosis. Besides that, the treatment increased angiogenesis and strongly improved cardiac function of the LV. MTX, possibly through an increase in the production of intracellular adenosine, could be considered as a feasible treatment for TC. Acknowledgement/Funding FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo)