Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats

Although obesity is an independent risk factor for heart failure and even mild-to-moderate forms of obesity are associated with myocardial systolic dysfunction the mechanisms of the myocardial dysfunction have not been identified. We assessed whether dietary-induced obesity is associated with an inc...

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Autores principales:	Leanda Vengethasamy, Olebogeng H.I. Majane, Eugene F. du Toit, Gavin R. Norton, Angela J. Woodiwiss
Formato:	article
Lenguaje:	EN
Publicado:	South African Heart Association 2017
Materias:	obesity heart failure cardiomyocyte apoptosis Diseases of the circulatory (Cardiovascular) system RC666-701
Acceso en línea:	https://doaj.org/article/d7fd4aa7ca054bb3814cdbabedb2a5c4
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spelling	oai:doaj.org-article:d7fd4aa7ca054bb3814cdbabedb2a5c42021-11-22T08:23:46ZImpact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats10.24170/6-3-19841996-67412071-4602https://doaj.org/article/d7fd4aa7ca054bb3814cdbabedb2a5c42017-04-01T00:00:00Zhttps://www.journals.ac.za/index.php/SAHJ/article/view/1984https://doaj.org/toc/1996-6741https://doaj.org/toc/2071-4602Although obesity is an independent risk factor for heart failure and even mild-to-moderate forms of obesity are associated with myocardial systolic dysfunction the mechanisms of the myocardial dysfunction have not been identified. We assessed whether dietary-induced obesity is associated with an increased sensitivity of the myocardium to ß-adrenergic-induced cardiomyocyte apoptosis or fibrosis. To induce obesity, rats were fed a diet that promotes an increased caloric intake. Adrenergic-induced cardiomyocyte apoptosis was determined by injecting rats for 5 days with isoproterenol (0.01 mg/kg/day for 3 days and 0.02 mg/kg/day for 2 days) and then studying the degree of cardiomyocyte damage using a TUNEL assay and assessing the pathological score. Five months of feeding rats a diet that promoted the development of an increased body weight (Control=481±4.3 g, Diet=550±7.8 g, p‹0.001) and visceral fat content (Control=19.6±0.8 g, Diet=33.0±1.2 g, p‹0.0001), did not alter baseline cardiomyocyte apoptosis. However, 5 days of ß-adrenergic activation resulted in an enhanced cardiomyocyte apoptosis in rats receiving the experimental diet as compared to rats receiving a normal diet (p‹0.01). No changes in the myocardial pathological score (fibrosis) were noted. The enhanced adrenergic-induced cardiomyocyte apoptosis in obese rats could not be explained by dietary-induced increases in baseline left ventricular internal diameters, decreases in systolic function (endocardial or midwall fractional shortening) or differences in the response of the heart to adrenergic-induced increases in inotropic or chronotropic function. In conclusion, the present study suggests that obesity may contribute to myocardial dysfunction by increasing the sensitivity of the myocardium to adrenergic-induced cardiomyocyte damage.Leanda VengethasamyOlebogeng H.I. MajaneEugene F. du ToitGavin R. NortonAngela J. WoodiwissSouth African Heart Associationarticleobesityheart failurecardiomyocyte apoptosisDiseases of the circulatory (Cardiovascular) systemRC666-701ENSA Heart Journal, Vol 6, Iss 3, Pp 154-160 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	obesity heart failure cardiomyocyte apoptosis Diseases of the circulatory (Cardiovascular) system RC666-701
spellingShingle	obesity heart failure cardiomyocyte apoptosis Diseases of the circulatory (Cardiovascular) system RC666-701 Leanda Vengethasamy Olebogeng H.I. Majane Eugene F. du Toit Gavin R. Norton Angela J. Woodiwiss Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
description	Although obesity is an independent risk factor for heart failure and even mild-to-moderate forms of obesity are associated with myocardial systolic dysfunction the mechanisms of the myocardial dysfunction have not been identified. We assessed whether dietary-induced obesity is associated with an increased sensitivity of the myocardium to ß-adrenergic-induced cardiomyocyte apoptosis or fibrosis. To induce obesity, rats were fed a diet that promotes an increased caloric intake. Adrenergic-induced cardiomyocyte apoptosis was determined by injecting rats for 5 days with isoproterenol (0.01 mg/kg/day for 3 days and 0.02 mg/kg/day for 2 days) and then studying the degree of cardiomyocyte damage using a TUNEL assay and assessing the pathological score. Five months of feeding rats a diet that promoted the development of an increased body weight (Control=481±4.3 g, Diet=550±7.8 g, p‹0.001) and visceral fat content (Control=19.6±0.8 g, Diet=33.0±1.2 g, p‹0.0001), did not alter baseline cardiomyocyte apoptosis. However, 5 days of ß-adrenergic activation resulted in an enhanced cardiomyocyte apoptosis in rats receiving the experimental diet as compared to rats receiving a normal diet (p‹0.01). No changes in the myocardial pathological score (fibrosis) were noted. The enhanced adrenergic-induced cardiomyocyte apoptosis in obese rats could not be explained by dietary-induced increases in baseline left ventricular internal diameters, decreases in systolic function (endocardial or midwall fractional shortening) or differences in the response of the heart to adrenergic-induced increases in inotropic or chronotropic function. In conclusion, the present study suggests that obesity may contribute to myocardial dysfunction by increasing the sensitivity of the myocardium to adrenergic-induced cardiomyocyte damage.
format	article
author	Leanda Vengethasamy Olebogeng H.I. Majane Eugene F. du Toit Gavin R. Norton Angela J. Woodiwiss
author_facet	Leanda Vengethasamy Olebogeng H.I. Majane Eugene F. du Toit Gavin R. Norton Angela J. Woodiwiss
author_sort	Leanda Vengethasamy
title	Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
title_short	Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
title_full	Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
title_fullStr	Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
title_full_unstemmed	Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
title_sort	impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats
publisher	South African Heart Association
publishDate	2017
url	https://doaj.org/article/d7fd4aa7ca054bb3814cdbabedb2a5c4
work_keys_str_mv	AT leandavengethasamy impactofdietaryinducedobesityonadrenergicinducedcardiomyocytedamageinrats AT olebogenghimajane impactofdietaryinducedobesityonadrenergicinducedcardiomyocytedamageinrats AT eugenefdutoit impactofdietaryinducedobesityonadrenergicinducedcardiomyocytedamageinrats AT gavinrnorton impactofdietaryinducedobesityonadrenergicinducedcardiomyocytedamageinrats AT angelajwoodiwiss impactofdietaryinducedobesityonadrenergicinducedcardiomyocytedamageinrats
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Impact of dietary-induced obesity on adrenergic-induced cardiomyocyte damage in rats

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