P81Changes on right ventricle induced by a high caloric diet and a left ventricle model of pressure overload

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Abstract

Purpose: Two major cardiovascular risk factors are hypertension and metabolic syndrome. This study aimed to evaluate the influence of a high-caloric diet, left ventricle (LV) chronic pressure overload, and their combination on right ventricle (RV) structure and function. Methods: Wistar rats (60-80g) were subjected to ascending aorta constriction (Ba) or sham procedure (Sh). After 2 weeks the animals were randomly divided and fed with a regular diet (Rd,2.9kcal) or with a western-type diet rich in carbohydrates, fat and salt(Hd,5.4kcal), resulting in 4 groups: Sh+Rd, Sh+Hd, Ba+Rd, Ba+Hd. After 8weeks of protocol RV function was assessed by pressure-volume catheters and samples obtained for morpho-histological and molecular analysis. Data presented as mean ±SEM. α vs. Sh+Rd, β vs. Ba+Rd, δ vs. Sh+Hd. p<0.05. Results: The administration of a western-type diet resulted in increased fat depots, visceral adipocyte hypertrophy, cardiomyocyte cross sectional area (CSA) and collagen III overexpression, in both Hd groups (Img1). These structural changes reflected in RV function by increased Pmax, dP/dtmax as well as impaired relaxation seen by the constant t. Constriction of ascending aorta for 8weeks resulted in increased heart/tibial length (TL) ratio, RV Pmax as well as RV cardiomyocyte hypertrophy together with BNP overexpression (Ba+Rd).The concomitant presence of these two cardiovascular risk factors in Ba+Hd animals led to a significant heart and RV cardiomyocyte hypertrophy as well as collagen I overexpression. Conclusions: This study demonstrates that both Western diet consumption and LV chronic pressure overload induce RV structural and functional changes and that the combination of these factors further promotes hypertrophy and extracellular matrix changes in the non-overloaded ventricle.

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