Abstract
BackgroundThe composition of a diet can influence myocardial metabolism and development of left ventricular hypertrophy (LVH). The impact of a high-fat diet in chronic left ventricular volume overload (VO) causing eccentric LVH is unknown. This study examined the effects of chronic ingestion of a high-fat diet in rats with chronic VO caused by severe aortic valve regurgitation (AR) on LVH, function and on myocardial energetics and survival.MethodsMale Wistar rats were divided in four groups: Shams on control or high-fat (HF) diet (15 rats/group) and AR rats fed with the same diets (ARC (n = 56) and ARHF (n = 32)). HF diet was started one week before AR induction and the protocol was stopped 30 weeks later.ResultsAs expected, AR caused significant LV dilation and hypertrophy and this was exacerbated in the ARHF group. Moreover, survival in the ARHF group was significantly decreased compared the ARC group. Although the sham animals on HF also developed significant obesity compared to those on control diet, this was not associated with heart hypertrophy. The HF diet in AR rats partially countered the expected shift in myocardial energy substrate preference usually observed in heart hypertrophy (from fatty acids towards glucose). Systolic function was decreased in AR rats but HF diet had no impact on this parameter. The response to HF diet of different fatty acid oxidation markers as well as the increase in glucose transporter-4 translocation to the plasma membrane compared to ARC was blunted in AR animals compared to those on control diet.ConclusionsHF diet for 30 weeks decreased survival of AR rats and worsened eccentric hypertrophy without affecting systolic function. The expected adaptation of myocardial energetics to volume-overload left ventricle hypertrophy in AR animals seemed to be impaired by the high-fat diet suggesting less metabolic flexibility.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2261-14-123) contains supplementary material, which is available to authorized users.
Highlights
The composition of a diet can influence myocardial metabolism and development of left ventricular hypertrophy (LVH)
Clinical data and animal characteristics All animals were alive at the end of the 8-week protocol with the exception of two deaths in the ARHF group
Cardiac metabolism We have previously showed that eccentric LVH caused by severe aortic valve regurgitation (AR) was associated with a shift in energy substrates preference from fatty acids to glucose [14,15,21]
Summary
The composition of a diet can influence myocardial metabolism and development of left ventricular hypertrophy (LVH). The impact of a high-fat diet in chronic left ventricular volume overload (VO) causing eccentric LVH is unknown. The direct cardiac toxicity of dietary sugar overabundance has been documented in animal models [1,2,3] but the effects of HF diets on the heart are still controversial [4]. This is probably due to the variability of the HF diets that have been studied in rodent models of heart diseases. The impact of a HF diet on dilated cardiomyopathy and eccentric LVH resulting from chronic LV volume overload (VO) has never been studied
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