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AT1Receptor Blockade Improves Myocardial Functional Performance in Obesity
Silvio Assis de Oliveira-Junior1, Nayara de Araújo Muzili1, Marianna Rabelo de Carvalho1
1Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil.
Arquivos Brasileiros De Cardiologia
|May 14, 2020
Summary
Losartan treatment improved heart muscle function in obese rats. Blocking the angiotensin-II receptor type 1 (AT1 receptor) with losartan countered negative effects of a high-fat diet on cardiac performance.
Area of Science:
- Cardiology
- Obesity Research
- Pharmacology
Background:
- Obesity is linked to chronic renin-angiotensin-aldosterone system activation.
- Obesity significantly alters cardiac performance.
- High-fat diet-induced obesity in rats serves as a model for studying cardiovascular changes.
Purpose of the Study:
- To investigate the impact of blocking the angiotensin-II receptor type 1 (AT1 receptor) on cardiac morphology and function.
- To assess the effects of losartan in rats with diet-induced obesity.
Main Methods:
- Wistar rats were fed either a control or high-fat diet for 20 weeks.
- Groups included Control (CO), Obese (OB), Control Losartan (CL), and Obese Losartan (OL).
- Losartan was administered for the final four weeks; body composition, blood pressure, and echocardiography were analyzed.
- Papillary muscle function was assessed under various conditions, including calcium concentration changes and beta-adrenergic stimulation.
Main Results:
- Obesity was associated with cardiac hypertrophy and increased left ventricle posterior wall shortening velocity.
- Losartan treatment (OL group) demonstrated improved myocardial contractility, evidenced by higher -dT/dt and +dT/dt values compared to obese (OB) and control losartan (CL) groups.
- Papillary muscle function, particularly under elevated calcium concentrations, showed enhanced performance in the losartan-treated obese group (OL).
Conclusions:
- Losartan effectively improves myocardial functional performance in the context of high-fat diet-induced obesity.
- AT1 receptor blockade with losartan mitigates detrimental cardiac effects associated with obesity.
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