Bicuspid aortic valve aortopathy is characterized by embryonic epithelial to mesenchymal transition and endothelial instability.

David Freiholtz, Otto Bergman, Karin Lång, Flore-Anne Poujade, Valentina Paloschi, Carl Granath, Jan H N Lindeman, Christian Olsson, Anders Franco-Cereceda, Per Eriksson, Hanna M Björck

Journal of molecular medicine (Berlin, Germany) 2023 Jul

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Bicuspid aortic valve (BAV) is the most common congenital heart malformation frequently associated with ascending aortic aneurysm (AscAA). Epithelial to mesenchymal transition (EMT) may play a role in BAV-associated AscAA. The aim of the study was to investigate the type of EMT associated with BAV aortopathy using patients with a tricuspid aortic valve (TAV) as a reference. The state of the endothelium was further evaluated. Aortic biopsies were taken from patients undergoing open-heart surgery. Aortic intima/media miRNA and gene expression was analyzed using Affymetrix human transcriptomic array. Histological staining assessed structure, localization, and protein expression. Migration/proliferation was assessed using ORIS migration assay. We show different EMT types associated with BAV and TAV AscAA. Specifically, in BAV-associated aortopathy, EMT genes related to endocardial cushion formation were enriched. Further, BAV vascular smooth muscle cells were less proliferative and migratory. In contrast, TAV aneurysmal aortas displayed a fibrotic EMT phenotype with medial degenerative insults. Further, non-dilated BAV aortas showed a lower miRNA-200c-associated endothelial basement membrane LAMC1 expression and lower CD31 expression, accompanied by increased endothelial permeability indicated by increased albumin infiltration. Embryonic EMT is a characteristic of BAV aortopathy, associated with endothelial instability and vascular permeability of the non-dilated aortic wall. KEY MESSAGES: Embryonic EMT is a feature of BAV-associated aortopathy. Endothelial integrity is compromised in BAV aortas prior to dilatation. Non-dilated BAV ascending aortas are more permeable than aortas of tricuspid aortic valve patients. © 2023. The Author(s).

Citation

David Freiholtz, Otto Bergman, Karin Lång, Flore-Anne Poujade, Valentina Paloschi, Carl Granath, Jan H N Lindeman, Christian Olsson, Anders Franco-Cereceda, Per Eriksson, Hanna M Björck. Bicuspid aortic valve aortopathy is characterized by embryonic epithelial to mesenchymal transition and endothelial instability. Journal of molecular medicine (Berlin, Germany). 2023 Jul;101(7):801-811