Cardiac, mandibular and thymic phenotypical association indicates that cranial neural crest underlies bicuspid aortic valve formation in hamsters

• Published in: PloS one 2017-09, Vol.12 (9), p.e0183556-e0183556
• Main Authors: Martínez-Vargas, Jessica, Ventura, Jacint, Machuca, Ángela, Muñoz-Muñoz, Francesc, Fernández, María Carmen, Soto-Navarrete, María Teresa, Durán, Ana Carmen, Fernández, Borja
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Aorta; Aortic valve; Aortic Valve - abnormalities; Aortic Valve - growth & development; Bicuspid Aortic Valve Disease; Biology and Life Sciences; Birth defects; Congenital defects; Congenital diseases; Congenital heart defects; Coronary vessels; Cricetinae; Development and progression; Differentiation; Embryogenesis; Embryonic growth stage; Evolution & development; Genetic aspects; Hamsters; Heart; Heart - physiology; Heart diseases; Heart Valve Diseases; Inbreeding; Mammals; Mandible; Mandible - physiology; Medicine and Health Sciences; Mesocricetus; Morphology; Neural crest; Neural Crest - physiology; Phenotype; Phenotypic variations; Physiological aspects; Quantitative genetics; Risk factors; Skull; Skull - physiology; Thymus; Thymus Gland - physiology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0183556

Bicuspid aortic valve (BAV) is the most prevalent human congenital cardiac malformation. It may appear isolated, associated with other cardiovascular malformations, or forming part of syndromes. Cranial neural crest (NC) defects are supposed to be the cause of the spectrum of disorders associated with syndromic BAV. Experimental studies with an inbred hamster model of isolated BAV showed that alterations in the migration or differentiation of the cardiac NC cells in the embryonic cardiac outflow tract are most probably responsible for the development of this congenital valvular defect. We hypothesize that isolated BAV is not the result of local, but of early alterations in the behavior of the NC cells, thus also affecting other cranial NC-derived structures. Therefore, we tested whether morphological variation of the aortic valve is linked to phenotypic variation of the mandible and the thymus in the hamster model of isolated BAV, compared to a control strain. Our results show significant differences in the size and shape of the mandible as well as in the cellular composition of the thymus between the two strains, and in mandible shape regarding the morphology of the aortic valve. Given that both the mandible and the thymus are cranial NC derivatives, and that the cardiac NC belongs to the cephalic domain, we propose that the causal defect leading to isolated BAV during embryonic development is not restricted to local alterations of the cardiac NC cells in the cardiac outflow tract, but it is of pleiotropic or polytopic nature. Our results suggest that isolated BAV may be the forme fruste of a polytopic syndrome involving the cranial NC in the hamster model and in a proportion of affected patients.