TY - JOUR
T1 - Activation and functional significance of the renin-angiotensin system in mice with cardiac restricted overexpression of tumor necrosis factor
AU - Flesch, Markus
AU - Höper, Anje
AU - Dell'Italia, Louis
AU - Evans, Kenda
AU - Bond, Richard
AU - Peshock, Ronald
AU - Diwan, Abhinav
AU - Brinsa, Theresa A.
AU - Wei, Chih Chang
AU - Sivasubramanian, Natarajan
AU - Spinale, Francis G.
AU - Mann, Douglas L.
PY - 2003/8/5
Y1 - 2003/8/5
N2 - Background - The functional significance of cross-regulation between the renin-angiotensin system (RAS) and tumor necrosis factor (TNF) has been established in nonmyocyte cell types; however, the degree and functional significance of the interaction between RAS and TNF has not been characterized in the heart. Methods and Results - We examined the expression of components of the RAS in a line of transgenic mice (MHCsTNF) with cardiac restricted overexpression of TNF. When examined at 4, 8, and 12 weeks of age, the MHCsTNF mice had increased activation of myocardial RAS, as shown by an increase in ACE mRNA level and ACE activity and increased angiotensin II peptide levels. Furthermore, myocardial angiotensin receptor mRNA and protein levels were reduced in the MHCsTNF mice, consistent with homologous desensitization of the receptors. However, expression of renin and angiotensinogen was not increased in MHCsTNF mice compared with littermate controls. To determine the functional significance of RAS activation in the MHCsTNF mice, we treated the mice with an angiotensin type I receptor antagonist, losartan (30 mg/kg), or diluent from 4 to 8 weeks of age. Analysis of cardiac structure with MRI showed that treatment with losartan normalized left ventricular mass and wall thickness. Furthermore, treatment with losartan reduced myocardial collagen content and reduced the incidence of myocyte apoptosis. Conclusions - Taken together, these results show that there are functionally significant interactions between RAS and TNF in the heart and that these interactions play an important role in the development and progression of left ventricular remodeling.
AB - Background - The functional significance of cross-regulation between the renin-angiotensin system (RAS) and tumor necrosis factor (TNF) has been established in nonmyocyte cell types; however, the degree and functional significance of the interaction between RAS and TNF has not been characterized in the heart. Methods and Results - We examined the expression of components of the RAS in a line of transgenic mice (MHCsTNF) with cardiac restricted overexpression of TNF. When examined at 4, 8, and 12 weeks of age, the MHCsTNF mice had increased activation of myocardial RAS, as shown by an increase in ACE mRNA level and ACE activity and increased angiotensin II peptide levels. Furthermore, myocardial angiotensin receptor mRNA and protein levels were reduced in the MHCsTNF mice, consistent with homologous desensitization of the receptors. However, expression of renin and angiotensinogen was not increased in MHCsTNF mice compared with littermate controls. To determine the functional significance of RAS activation in the MHCsTNF mice, we treated the mice with an angiotensin type I receptor antagonist, losartan (30 mg/kg), or diluent from 4 to 8 weeks of age. Analysis of cardiac structure with MRI showed that treatment with losartan normalized left ventricular mass and wall thickness. Furthermore, treatment with losartan reduced myocardial collagen content and reduced the incidence of myocyte apoptosis. Conclusions - Taken together, these results show that there are functionally significant interactions between RAS and TNF in the heart and that these interactions play an important role in the development and progression of left ventricular remodeling.
KW - Apoptosis
KW - Genes
KW - Heart failure
KW - Hypertrophy
KW - Remodeling
UR - http://www.scopus.com/inward/record.url?scp=0042074072&partnerID=8YFLogxK
U2 - 10.1161/01.CIR.0000081768.13378.BF
DO - 10.1161/01.CIR.0000081768.13378.BF
M3 - Article
C2 - 12874189
AN - SCOPUS:0042074072
SN - 0009-7322
VL - 108
SP - 598
EP - 604
JO - Circulation
JF - Circulation
IS - 5
ER -