Angiotensin-(1-7) improves cardiac remodeling and inhibits growth-promoting pathways in the heart of fructose-fed rats.
The present study examined whether chronic treatment with angiotensin (ANG)-(1-7) reduces cardiac remodeling and inhibits growth-promoting signaling pathways in the heart of fructose-fed rats (FFR), an animal model of insulin resistance. Sprague-Dawley rats were fed either normal rat chow (control) or the same diet plus 10% fructose in drinking water. For the last 2 wk of a 6-wk period of the corresponding diet, control and FFR were implanted with osmotic pumps that delivered ANG-(1-7) (100 ng.kg(-1).min(-1)). A subgroup of each group of animals (control or FFR) underwent a sham surgery. We determined heart weight, myocyte diameter, interstitial fibrosis, and perivascular collagen type III deposition as well as the phosphorylation degree of ERK1/2, JNK1/2, and p38MAPK. FFR showed a mild hypertension that was significantly reduced after ANG-(1-7) treatment. Also, FFR displayed higher ANG II circulating and local levels in the heart that remained unaltered after chronic ANG-(1-7) infusion. An increased heart-to-body weight ratio, myocyte diameter, as well as left ventricular fibrosis and perivascular collagen type III deposition were detected in the heart of FFR. Interestingly, significant improvements in these cardiac alterations were obtained after ANG-(1-7) treatment. Finally, FFR that received ANG-(1-7) chronically displayed significantly lower phosphorylation levels of ERK1/2, JNK1/2, and p38MAPK. The beneficial effects obtained by ANG-(1-7) were associated with normal values of Src-homology 2-containing protein-tyrosine phosphatase-1 (SHP-1) activity in the heart. In conclusion, chronic ANG-(1-7) treatment ameliorated cardiac hypertrophy and fibrosis and attenuated the growth-promoting pathways in the heart. These findings show an important protective role of ANG-(1-7) in the heart of insulin-resistant rats.
Giani
Jorge F
JF
Instituto de Química y Fisicoquímica Biológicas, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas of Argentina, Argentina.
Muñoz
Marina C
MC
Mayer
Marcos A
MA
Veiras
Luciana C
LC
Arranz
Cristina
C
Taira
Carlos A
CA
Turyn
Daniel
D
Toblli
Jorge E
JE
Dominici
Fernando P
FP
D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000502:physiology; D004040:Dietary Carbohydrates / Q000009:adverse effects; D004195:Disease Models, Animal; D005632:Fructose / Q000009:adverse effects*; D006973:Hypertension / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020257:Ventricular Remodeling / Q000187:drug effects*
D000959:Antihypertensive Agents; D004040:Dietary Carbohydrates; D007328:Insulin; D010446:Peptide Fragments; D000804:Angiotensin II; D005632:Fructose; D000803:Angiotensin I; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C509250:Ptpn6 protein, rat; C118790:angiotensin I (1-7)