Abstract 614: Anti-inflammatory Effect of Ang-(1-7) non-peptide mimetic (AVE 0991), on T Cell Infiltration in Perivascular Adipose Tissue in ApoE-/- Mice

Abstract

Angiotensin 1-7 (Ang 1-7) has anti-atherosclerotic effects, possibly through its anti-inflammatory properties. As perivascular inflammation is an important component of early atherosclerosis, we aimed to determine whether angiotensin-(1-7) non peptide mimetic (AVE0991) can modulate these inflammatory mechanisms in the early development of atherosclerosis. Twelve-week old ApoE-/- mice and controls (C57BL/6J) on chow diet were treated with placebo or AVE0991 (0.58μM/g/day, per os). Mice were analysed at 16, 20 and 24 weeks of age. The level of perivascular leukocyte and T cell infiltration was measured by flow cytometry. Atherosclerotic plaque area was assessed by Oil Red O staining of en-face aortic preparations. Endothelial dysfunction was measured by wire myography and ROS production in the aorta by lucigenin-enhanced chemiluminescence (5μM). RESULTS: Levels of endogenous Ang 1-7, measured by mass spectrometry in the perivascular adipose tissue were low in both WT and ApoE-/- (32.9±1.2 vs 31.1±1.1 pg/mg; p=0.1). AVE0991 significantly reduced plaque area in ApoE-/- mice at all time points (14.2±1.9% vs 7.25±1.3% at 24 weeks; p<0.05). During this early stage of atherosclerosis there was no evidence of endothelial dysfunction and no significant increase in ROS generation in ApoE-/- mice. However, there was significant perivascular inflammation in 16 week old ApoE mice: CD45+ leukocytes were 2 fold higher in ApoE-/- mice vs controls (3200±850 vs 1700±267 cells/mg; p<0.05) and the number of CD3+ T in ApoE-/- mice was higher than in C57Bl/6J (638±88 vs 310±64 cells/mg; p<0.05). With aging, the number of leukocytes and T cells further increased in ApoE-/- but not in C57BL/6J mice, an effect abrogated by AVE0991. Moreover in cell culture of SW872 preadipocytes, AVE 0991 preincubation abolished TNF-α induced increase of chemokine RANTES and IL-6 mRNA expression. CONCLUSION: Ang-(1-7) non-peptide mimetic (AVE 0991) effectively inhibits early perivascular inflammation during the development of atherosclerotic plaque. This occurs independently of changes in redox status or endothelial dysfunction.