Activation and functional significance of the renin-angiotensin system in mice with cardiac restricted overexpression of tumor necrosis factor

Markus Flesch, Anje Höper, Louis Dell'Italia, Kenda Evans, Richard Bond, Ronald M Peshock, Abhinav Diwan, Theresa A. Brinsa, Chih Chang Wei, Natarajan Sivasubramanian, Francis G. Spinale, Douglas L. Mann

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)598-604
Number of pages7
JournalCirculation
Volume108
Issue number5
DOIs
StatePublished - Aug 5 2003

Keywords

  • Apoptosis
  • Genes
  • Heart failure
  • Hypertrophy
  • Remodeling

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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