Abstract 679: Modeling Thoracic Aortic Aneurysm of Bicuspid Aortic Valve Patients with Induced Pluripotent Stem Cells Reveals Distinct Phenotypes of Smooth Muscle Cells from Different LIneages

Ascending aortic aneurysm occurs in 35%-68% patients with bicuspid aortic valves (BAV), which is more frequently than it does in patients with normal trileaflet aortic valves (TAV). In contrast to recurrent aneurysms of the ascending aorta, descending aortic aneurysms is very rare in patients with BAV. Vascular Smooth Muscle Cells (SMCs) make up the media of the aortic walls, and their contractile properties help sustain vessel tone. Interestingly, ascending aorta is populated by SMCs arising from neural crest and descending aorta by SMCs from paraxial mesoderm. An intriguing hypothesis is that the distinct susceptibility of aneurysm in the ascending and descending aorta in patients with BAV is due in part to disparities in SMC embryonic origins. To prove our hypothesis, we used an induced Pluripotent Stem Cells (iPS) model system to generate SMCs from neural crest and paraxial mesoderm. Firstly, iPSCs were established from a patient with BAV and ascending thoracic aortic aneurysm (BAV/TAA) and two contro...