01.05 Statins Reduce Thoracic Aortic Aneurysm Growth in Marfan Syndrome Mice

M. P. Fischbein1  1Stanford University,Cardiothoracic Surgery,Palo Alto, CA, USA

Introduction: Systematically dissect the prenylation pathway to better define the mechanism behind the beneficial effect of statins on aneurysm reduction in MFS and anticipate this will help elucidate the pathophysiology of aneurysm formation.  

Methods: Fbn1C1039G/+ mice (4 week old) were treated subcutaneously with either (a) Pravastatin (PS) (HMG-Co Reductase inhibitor) (100 mg/kg per day); (b) Manumycin A (MA) (FPT inhibitor) (2.5 mg/kg/every other day); (c) Perillyl Alcohol (PA) (GGPT-1 and -2 inhibitor) (5.0 mg/kg/every other day); or (d) vehicle control Fbn1C1039G/+ mice from age 4-8 weeks. Aortic dimensions were measured with transthoracic echo.

Results:  PS and MA significantly reduced aneurysm growth compared to vehicle control (PS:1.57 ± 0.03 mm; MA: 1.55 ± 0.06 mm; vehicle: 1.77 ± 0.05 mm, respectively: p < 0.05). There was no significant difference between PS and MA treated groups. In contrast, PA did not significantly decrease aneurysm size (PA: 1.81 ± 0.06 mm). Elastin staining illustrated reduced elastin breakdown in MA treated mice compared to vehicle control treated groups (MA: 2.2 ± 0.3, vehicle: 4.2 ± 0.6, respectively: p < 0.05). After identifying that the Ras pathway is important, we measured the relative expression of pRaf-1 and pErk1/2, downstream enzymes in transforming growth factor- β (TGF-β) signaling pathway with WES. Although elevated in control Marfan mice, both pRaf-1 and pErk 1/2 were significantly reduced in MA treated mice, corresponding with a reduction in aneurysm growth (pRaf-1: MA: 5.1 ± 1.3, vehicle: 8.8 ± 0.8, p = 0.08, pErk1/2: MA: 2.3 ± 0.1, vehicle: 3.2 ± 0.1, p < 0.05, respectively

Conclusion: Statins reduce aortic aneurysm growth in Fbn1C1039G/+ Marfan mice by decreasing both Ras activation and downstream ERK signaling