Abstract 12710: The Role of Cellular Senescence in Aortic Dissection

Abstract

Background: Aortic dissection (AD) is a catastrophic disease with high mortality and serious complications, and its molecular pathogenesis is largely unknown. The importance of inflammation in AD has been reported. Recently we found that cell proliferation precedes the inflammatory response in AD. Cell proliferation causes cellular senescence that induces inflammatory response, however, role of cellular senescence in AD has not been elucidated. Objective: We investigated if cellular senescence contributes to AD pathogenesis in mouse AD model. Methods and Results: A mouse AD model was created by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII) for 14days. BAPN+AngII infusion induced senescence markers from day 3, before AD onset, and persisted until day14. Senescent cells, as demonstrated by the expression of senescence-associated beta-galactosidase, were evident in intimal endothelial cells, medial smooth muscle cells, adventitial macrophages, and fibroblasts. To examine role of cellular senescence in AD, we orally administrated ABT263 known as “senolytics” that eliminates senescent cells. ABT263 treatment reduced the expression of the senescence markers. The AD mortality of ABT263 group was 35%, which was lower than that of vehicle group(66.7%, P < 0.05 by log-rank test). The severity of AD, as assessed by the lesion length in vehicle group was 33.2 ± 3.1mm, whereas that in ABT263 group was 24.6 ± 1.8mm (P < 0.05). Transcriptome analysis revealed that ABT263 treatment suppressed the immune and inflammatory response in the aorta before AD onset. Quantitative RT-PCR confirmed that ABT263 treatment prevented the induction of p21Cip1, interleukin-6 and several chemokines. Bioplex analysis of mice’s serum showed that ABT263 decreased inflammatory molecules in mice’s serum compared to vehicle group. Moreover, aortic smooth muscle cells(SMCs)remained contractile phenotype in ABT263 group, whereas BAPN+AngII reduced the phenotype in vehicle group. Conclusions: Elimination of senescent cells prevented AD progression and death in mice. ABT263 suppressed the inflammatory response and contributed to retain the SMCs phenotype. Cellular senescence represents a potential predictor and a therapeutic target for AD.