Background: Abdominal aortic aneurysms (AAAs) are permanent dilations of the abdominal aorta with 4-5 times greater prevalence in males than in females. The aim of this study is to define whether Celastrol, a pentacyclic triterpene from the root extracts of Tripterygium wilfordii, supplementation influences angiotensin II (AngII)-induced AAAs in hypercholesterolemic mice.
Methods: Age-matched (8-12 weeks old) male and female low-density lipoprotein (Ldl) receptor-deficient mice were fed a fat-enriched diet supplemented with or without Celastrol (10 mg/kg/day) for five weeks. After one week of diet feeding, mice were infused with either saline (n = 5 per group) or AngII (500 or 1000 ng/kg/min, n = 12-15 per group) for 28 days.
Results: Dietary supplementation of Celastrol profoundly increased AngII-induced abdominal aortic luminal dilation and external aortic width in male mice as measured by ultrasonography and ex vivo measurement, with a significant increase in incidence compared to the control group. Celastrol supplementation in female mice resulted in significantly increased AngII-induced AAA formation and incidence. In addition, Celastrol supplementation significantly increased AngII-induced aortic medial elastin degradation accompanied by significant aortic MMP9 activation in both male and female mice compared to saline and AngII controls.
Conclusions: Celastrol supplementation to Ldl receptor-deficient mice ablates sexual dimorphism and promotes AngII-induced AAA formation, which is associated with increased MMP9 activation and aortic medial destruction.
Keywords: Celastrol; aneurysm; angiotensin II; elastin.