Background: Perivascular adipose tissue is implicated in vasoreactivity; however, its effect on atherosclerosis remains undefined.
Methods and results: We examined the effect of a high-cholesterol diet (HCD) on phenotypic alterations of the thoracic periaortic adipose tissue (tPAT) in apoE-deficient (apoE(-/-)) mice. Gene expression of the components of the renin angiotensin system and that of macrophage markers were significantly higher in apoE(-/-) mice fed an HCD than in those fed a chow diet (CD). These changes were absent both in angiotensin II (AngII) receptor blocker (ARB)-treated apoE(-/-) mice and in Ang II type 1 (AT1) receptor-deficient apoE(-/-) (Agtr1(-/-)/apoE(-/-)) mice. To evaluate their effect on atherosclerosis, we transplanted tPAT into apoE(-/-) mice alongside the distal abdominal aorta. Transplanted tPAT was harvested from apoE(-/-) and Agtr1(-/-)/apoE(-/-) mice fed a CD (tPAT-CD/apoE(-/-), tPAT-CD/Agtr1(-/-)/apoE(-/-)), HCD (tPAT-HCD/apoE(-/-), tPAT-HCD/Agtr1(-/-)/apoE(-/-)), or HCD in combination with ARB treatment (tPAT-HCD/ARB/apoE(-/-)). Four weeks after transplantation, a significantly increased oil red O-positive area was observed in the aorta of tPAT-HCD/apoE(-/-) mice than in tPAT-CD/apoE(-/-) mice. Such a change was absent in tPAT-HCD/ARB/apoE(-/-) and tPAT-HCD/Agtr1(-/-)/apoE(-/-) mice.
Conclusions: Our findings demonstrated that AT1 receptor plays a crucial role in HCD-induced phenotypic alterations of tPAT, modulation of which could exert beneficial effects on atherosclerosis.
Keywords: Thoracic periaortic adipose tissue; adipokines; atherosclerosis; macrophage; renin angiotensin system.
© The Author(s) 2014.