AIMS: Leptin resistance has been associated with cardiac lipotoxicity; however, whether leptin resistance is a risk factor associated with cardiac lipotoxicity at different time points in diet-induced obesity is unclear. The objective of this study was to evaluate this relationship. MAIN METHODS: Male Wistar rats were fed a normal chow diet (12% from fat) or a high-fat diet (49% from fat) for 15 and 45 weeks, respectively. The adiposity index, body weight and co-morbidities were evaluated. Heart lipotoxicity was assessed by analyzing cardiac function and morphological changes as well as cardiac triglyceride, ceramide and lipid hydroperoxide accumulations. Cardiac apoptosis was examined using the TUNEL method. Leptin function was determined by examining plasma leptin levels, cardiac leptin receptors (OB-R) and related phosphorylations of AMP-activated kinase protein (AMPK) and Acetyl CoA carboxylase (ACC). KEY FINDINGS: The diet-induced obesity was characterized by an elevated adiposity index, body weight and leptin levels at both 15 and 45 weeks. There was no difference between groups in the cardiac triglyceride or lipid hydroperoxide levels. Interestingly, ceramide levels decreased in obese animals in both experimental periods. The cardiac morphological and functional parameters were not altered. Although down-regulation of OB-R has occurred in chronic obesity, it did not adversely affect AMPK or ACC phosphorylation. SIGNIFICANCE: The development of obesity via long-term feeding of a high-fat diet to rats does not result in cardiac lipotoxicity but promotes the down-regulation of OB-R. However, this does not result in altered levels of AMPK or ACC phosphorylations in this animal model.
AIMS: Leptin resistance has been associated with cardiac lipotoxicity; however, whether leptin resistance is a risk factor associated with cardiac lipotoxicity at different time points in diet-induced obesity is unclear. The objective of this study was to evaluate this relationship. MAIN METHODS: Male Wistar rats were fed a normal chow diet (12% from fat) or a high-fat diet (49% from fat) for 15 and 45 weeks, respectively. The adiposity index, body weight and co-morbidities were evaluated. Heart lipotoxicity was assessed by analyzing cardiac function and morphological changes as well as cardiac triglyceride, ceramide and lipid hydroperoxide accumulations. Cardiac apoptosis was examined using the TUNEL method. Leptin function was determined by examining plasma leptin levels, cardiac leptin receptors (OB-R) and related phosphorylations of AMP-activated kinase protein (AMPK) and Acetyl CoA carboxylase (ACC). KEY FINDINGS: The diet-induced obesity was characterized by an elevated adiposity index, body weight and leptin levels at both 15 and 45 weeks. There was no difference between groups in the cardiac triglyceride or lipid hydroperoxide levels. Interestingly, ceramide levels decreased in obese animals in both experimental periods. The cardiac morphological and functional parameters were not altered. Although down-regulation of OB-R has occurred in chronic obesity, it did not adversely affect AMPK or ACC phosphorylation. SIGNIFICANCE: The development of obesity via long-term feeding of a high-fat diet to rats does not result in cardiac lipotoxicity but promotes the down-regulation of OB-R. However, this does not result in altered levels of AMPK or ACC phosphorylations in this animal model.
Authors: Ana Paula Lima-Leopoldo; André S Leopoldo; Danielle C T da Silva; André F do Nascimento; Dijon H S de Campos; Renata A M Luvizotto; Adriana F de Deus; Paula P Freire; Alessandra Medeiros; Katashi Okoshi; Antonio C Cicogna Journal: J Appl Physiol (1985) Date: 2014-06-26
Authors: Renata de Azevedo Melo Luvizotto; André Ferreira do Nascimento; Maria Teresa de Síbio; Regiane Marques Castro Olímpio; Sandro José Conde; Ana Paula Lima-Leopoldo; André Soares Leopoldo; Antonio Carlos Cicogna; Célia Regina Nogueira Journal: ScientificWorldJournal Date: 2012-05-03
Authors: Danielle Cristina Tomaz da Silva; Ana Paula Lima-Leopoldo; André Soares Leopoldo; Dijon Henrique Salomé de Campos; André Ferreira do Nascimento; Silvio Assis de Oliveira Junior; Carlos Roberto Padovani; Antonio Carlos Cicogna Journal: Arq Bras Cardiol Date: 2013-11-09 Impact factor: 2.000
Authors: Maria Teresa De Sibio; Renata Azevedo Melo Luvizotto; Regiane Marques Castro Olimpio; Camila Renata Corrêa; Juliana Marino; Miriane de Oliveira; Sandro José Conde; Ana Lúcia dos Anjos Ferreira; Carlos Roberto Padovani; Célia Regina Nogueira Journal: PLoS One Date: 2013-02-28 Impact factor: 3.240
Authors: Silvio A Oliveira Junior; Carlos R Padovani; Sergio A Rodrigues; Nilza R Silva; Paula F Martinez; Dijon Hs Campos; Marina P Okoshi; Katashi Okoshi; Maeli Dal-Pai; Antonio C Cicogna Journal: Cardiovasc Diabetol Date: 2013-04-15 Impact factor: 9.951