Effect of Hydralazine on Angiotensin II-Induced Abdominal Aortic Aneurysm in Apolipoprotein E-Deficient Mice

The rupture of an abdominal aortic aneurysm (AAA) causes about 200,000 deaths worldwide each year. However, there are currently no effective drug therapies to prevent AAA formation or, when present, to decrease progression and rupture, highlighting an urgent need for more research in this field. Increased vascular inflammation and enhanced apoptosis of vascular smooth muscle cells (VSMCs) are implicated in AAA formation. Here, we investigated whether hydralazine, which has anti-inflammatory and anti-apoptotic properties, inhibited AAA formation and pathological hallmarks. In cultured VSMCs, hydralazine (100 mu M) inhibited the increase in inflammatory gene expression and apoptosis induced by acrolein and hydrogen peroxide, two oxidants that may play a role in AAA pathogenesis. The anti-apoptotic effect of hydralazine was associated with a decrease in caspase 8 gene expression. In a mouse model of AAA induced by subcutaneous angiotensin II infusion (1 mu g/kg body weight/min) for 28 days in apolipoprotein E-deficient mice, hydralazine treatment (24 mg/kg/day) significantly decreased AAA incidence from 80% to 20% and suprarenal aortic diameter by 32% from 2.26 mm to 1.53 mm. Hydralazine treatment also significantly increased the survival rate from 60% to 100%. In conclusion, hydralazine inhibited AAA formation and rupture in a mouse model, which was associated with its anti-inflammatory and anti-apoptotic properties.