title: Antagonism of AT2 receptors augments angiotensin II-induced abdominal aortic aneurysms and atherosclerosis.
abstract: 1. We have recently demonstrated that chronic infusion of Angiotensin II into apoE-/- mice promotes the development of abdominal aortic aneurysms. To determine the involvement of specific Angiotensin II receptors in this response, we co-infused Angiotensin II (1000 ng kg(-1) min(-1) for 28 days) with losartan (30 mg kg(-1) day(-1)) or PD123319 (3 mg kg(-1) day(-1)) to antagonize AT1 and AT2 receptors, respectively. 2. Infusion of Angiotensin II promoted the development of abdominal aortic aneurysms in 70% of mature female apoE-/- mice. The formation of aortic aneurysms was totally inhibited by co-infusion of Angiotensin II with losartan (30 mg kg(-1) day(-1); P=0.003). In contrast, the co-infusion of Angiotensin II with PD123319 resulted in a marked increase in the incidence and severity of aortic aneurysms. 3. To determine whether AT2 antagonism also promoted Angiotensin II-induced atherosclerosis, Angiotensin II was infused into young female apoE-/- mice that had little spontaneous atherosclerosis. In these mice, co-infusion of PD123319 led to a dramatic increase in the extent of atherosclerosis. This increase was associated with no change in plasma lipid concentrations and only transient and modest increases in blood pressure during co-infusion with PD123319. 4. While antagonism of AT1 receptors totally prevented the formation of aneurysms, antagonism of AT2 receptors promoted a large increase in the severity of Angiotensin II-induced vascular pathology.
authors.affiliation: Division of Cardiovascular Medicine, Gill Heart Institute, University of Kentucky, Lexington, Kentucky, KY 40536 USA. adaugh@uky.edu
authors.forename: A
authors.initials: A
authors.lastname: Daugherty
authors.forename: M W
authors.initials: MW
authors.lastname: Manning
authors.forename: L A
authors.initials: LA
authors.lastname: Cassis
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000139:chemically induced* / Q000473:pathology; D001057:Apolipoproteins E / Q000235:genetics; D001161:Arteriosclerosis / Q000139:chemically induced* / Q000473:pathology; D004357:Drug Synergism; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D019808:Losartan / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011725:Pyridines / Q000494:pharmacology; D012720:Severity of Illness Index
chemical_list: D001057:Apolipoproteins E; D007093:Imidazoles; D011725:Pyridines; D000804:Angiotensin II; C073402:PD 123319; D019808:Losartan