APOE and aortic valve insufficiency: Aortic regurgitation was observed in the elderly (hypercholesterolemic and atherosclerotic) apoE-/- mouse but neither in the young (hypercholesterolemic) apoE-/- mouse nor in the elderly C57 control mouse (normocholesterolemic), indicating that this cardiac dysfunction is dependent on the concurrence of hypercholesterolemia and aging [61].