Saturated high-fat diet-induced obesity increases adenylate cyclase of myocardial -adrenergic system and does not compromise cardiac function

Author(s):Show less -

Vileigas, Danielle F. ^[1] ; de Deus, Adriana F. ^[1] ; da Silva, Danielle C. T. ^[1] ; de Tomasi, Loreta C. ^[1] ; de Campos, Dijon H. S. ^[1] ; Adorni, Caroline S. ^[1] ; de Oliveira, Scarlet M. ^[1] ; Sant'Ana, Paula G. ^[1] ; Okoshi, Katashi ^[1] ; Padovani, Carlos R. ^[2] ; Cicogna, Antonio C. ^[1]

Affiliation

^[1] Sao Paulo State Univ Julio de Mesquita Filho, Sch Med, Dept Internal Med, Sao Paulo - Brazil

^[2] Sao Paulo State Univ Julio de Mesquita Filho, Biosci Inst, Dept Biostat, Sao Paulo - Brazil

• Document type: Journal article
• Source: PHYSIOLOGICAL REPORTS; v. 4, n. 17 SEP 2016.
• Web of Science Citations: 4

Abstract

Obesity is a worldwide pandemic associated with high incidence of cardiovascular disease. The mechanisms by which the obesity leads cardiac dysfunction are not fully elucidated and few studies have evaluated the relationship between obesity and proteins involved in myocardial -adrenergic (A) system. The purpose of this study was to evaluate the cardiac function and A pathway components in myocardium of obese rats. Male Wistar rats were distributed into two groups: control (n=17; standard diet) and obese (n=17; saturated high-fat diet) fed for 33weeks. Nutritional profile and comorbidities were assessed. Cardiac structure and function was evaluated by macroscopic postmortem, echocardiographic and isolated papillary muscle analyzes. Myocardial protein expression of (1)- and (2)-adrenergic receptors, Gs protein, adenylate cyclase (AC) and protein kinase A (PKA) was performed by Western blot. Cardiac cyclic adenosine monophosphate (cAMP) levels and PKA activity were assessed by ELISA. Obese rats showed increased adiposity index (P<0.001) and several comorbidities as hypertension, glucose intolerance, insulin resistance, and dyslipidemia compared with control rats. Echocardiographic assessment revealed increased left atrium diameter (C: 4.98 +/- 0.38 vs. Ob: 5.47 +/- 0.53, P=0.024) and posterior wall shortening velocity (C: 37.1 +/- 3.6 vs. Ob: 41.8 +/- 3.8, P=0.007) in obese group. Papillary muscle evaluation indicated that baseline data and myocardial responsiveness to isoproterenol stimulation were similar between the groups. Protein expression of myocardial AC was higher in obese group than in the control (C: 1.00 +/- 0.21 vs. Ob: 1.25 +/- 0.10, P=0.025), whereas the other components were unchanged. These results suggest that saturated high-fat diet-induced obesity was not effective in triggering cardiac dysfunction and impair the beta-adrenergic signaling. (AU)

• FAPESP's process: 12/20725-7 - Influence of saturated high-fat diet induced obesity on the behavior of myocardial beta-adrenergic pathway in Wistar rats
• Grantee: Danielle Fernandes Vileigas
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 12/16647-0 - Participation of adrenergic system in the myocardial dysfunction induced by obesity
• Grantee: Antonio Carlos Cicogna
• Support type: Regular Research Grants