Influence of zinc supplementation on cardiac remodeling after myocardial infarction

Author(s)

Andréa de Freitas Gonçalves

• Document type: Doctoral Thesis
• Press: Botucatu. 2016-10-05.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina. Botucatu
• Defense date: 2016-08-08
• Advisor: Leonardo Antonio Mamede Zornoff; Fernanda Chiuso Minicucci

Abstract

The process of cardiac remodeling after myocardial infarction is associated with poor outcome. In the acute phase, remodeling promotes the formation of the aneurysm and predisposes to ventricular rupture. Chronically, it is associated with higher prevalence of malignant arrhythmias and ventricular dysfunction, because the non infarcted region undergoes genetic, structural and biochemical changes which will result in impairment of functional capacity of the heart and death. Therefore, strategies to attenuate remodeling result in improved prognosis after myocardial infarction. Thus, the role of zinc has been studied as an important factor. In our protocol, we assessed the effects of zinc supplementation in cardiac morphological and functional changes after acute myocardial infarction in rats, through the study of some of the main mechanisms involved in cardiac remodeling process: hypertrophy and changes in ventricular geometry, functional changes, collagen amount, oxidative stress and inflammation. In our results, we found that animals that received zinc (infarcted and sham) decreased the left ventricular systolic and diastolic area. In the assessment of systolic function, zinc attenuated the decrease in the posterior wall shortening velocity in infracted rats. In functional variables obtained by tissue echocardiography, infarction induced diastolic dysfunction (estimated by the E/ E') was attenuated by zinc. In the study of isolated heart, infarcted animals had lower systolic blood pressure and lower values of positive and negative derivative of pressure without influence of zinc. Additionally, zinc induced a decrease of IFN-γ, TNF-α and superoxide dismutase activity associated with increased catalase, glutathione peroxidase, IL-10 and total lymphocytes. There was no change with zinc supplementation in the evaluations of regulatory T lymphocytes in the spleen, activity of metalloproteinases 2 and 9 and Nrf-2 values. Thus, we conclude that zinc attenuated variables associated with infarction induced cardiac remodeling in rats, by modulation changes in oxidative stress and inflammation. (AU)

• FAPESP's process: 13/06862-4 - Influence of zinc supplementation on cardiac remodeling after myocardial infarction
• Grantee: Andréa de Freitas Gonçalves Della Ripa
• Support Opportunities: Scholarships in Brazil - Doctorate