J Am Coll Cardiol, 2009; 54:2312-2318
Bicuspid Aortic Valves With Different Spatial Orientations of the Leaflets Are Distinct Etiological Entities
Bicuspid Aortic Valves With Different Spatial Orientations of the Leaflets Are Distinct Etiological Entities
Borja Fernández, PhD*,*, Ana C. Durán, PhD*, Teresa Fernández-Gallego, BSc*, M. Carmen Fernández, BSc*, Miguel Such, MD, Josep M. Arqué, MD and Valentín Sans-Coma, PhD*
* Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain Department of Cardiovascular Surgery, University Hospital Virgen de la Victoria, Málaga, Spain Department of Cardiovascular Surgery, University Hospital Carlos Haya, Málaga, Spain
Objectives: The aim of this study was to decide whether bicuspid aortic valves (BAVs) with fused right and noncoronary leaflets (R-N) and BAVs with fused right and left leaflets (R-L) have different etiologies or are the product of a single diathesis.
Background: The BAV is the most common congenital cardiac malformation. The R-N and R-L BAVs are the most frequent BAV subtypes.
Methods: The study was carried out in adult and embryonic hearts of endothelium nitric oxide synthase knock-out mice and inbred Syrian hamsters with a high incidence of R-N and R-L BAVs, respectively. The techniques used were histochemistry, immunohistochemistry, and scanning electron microscopy.
Results: The R-N BAVs result from a defective development of the cardiac outflow tract (OT) endocardial cushions that generates a morphologically anomalous right leaflet. The left leaflet develops normally ("Vertical Orifice" seen in PSSAx echo view). The R-L BAVs are the outcome of an extrafusion of the septal and parietal OT ridges that thereby engenders a sole anterior leaflet. The noncoronary leaflet forms normally ("Horizontal Orifice" seen in PSSAx echo view...more common).
Conclusions: The R-N and R-L BAVs are different etiological entities. The R-N BAVs are the product of a morphogenetic defect that happens before the OT septation and that probably relies on an exacerbated nitric oxide–dependent epithelial-to-mesenchymal transformation. The R-L BAVs result from the anomalous septation of the proximal portion of the OT, likely caused by a distorted behavior of neural crest cells. Care should be taken in further work on BAV genetics because R-N and R-L BAVs might rely on different genotypes. Detailed screening for R-N and R-L BAVs should be performed for a better understanding of the relationships between these BAV morphologic phenotypes and other heart disease.
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* Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain Department of Cardiovascular Surgery, University Hospital Virgen de la Victoria, Málaga, Spain Department of Cardiovascular Surgery, University Hospital Carlos Haya, Málaga, Spain
Objectives: The aim of this study was to decide whether bicuspid aortic valves (BAVs) with fused right and noncoronary leaflets (R-N) and BAVs with fused right and left leaflets (R-L) have different etiologies or are the product of a single diathesis.
Background: The BAV is the most common congenital cardiac malformation. The R-N and R-L BAVs are the most frequent BAV subtypes.
Methods: The study was carried out in adult and embryonic hearts of endothelium nitric oxide synthase knock-out mice and inbred Syrian hamsters with a high incidence of R-N and R-L BAVs, respectively. The techniques used were histochemistry, immunohistochemistry, and scanning electron microscopy.
Results: The R-N BAVs result from a defective development of the cardiac outflow tract (OT) endocardial cushions that generates a morphologically anomalous right leaflet. The left leaflet develops normally ("Vertical Orifice" seen in PSSAx echo view). The R-L BAVs are the outcome of an extrafusion of the septal and parietal OT ridges that thereby engenders a sole anterior leaflet. The noncoronary leaflet forms normally ("Horizontal Orifice" seen in PSSAx echo view...more common).
Conclusions: The R-N and R-L BAVs are different etiological entities. The R-N BAVs are the product of a morphogenetic defect that happens before the OT septation and that probably relies on an exacerbated nitric oxide–dependent epithelial-to-mesenchymal transformation. The R-L BAVs result from the anomalous septation of the proximal portion of the OT, likely caused by a distorted behavior of neural crest cells. Care should be taken in further work on BAV genetics because R-N and R-L BAVs might rely on different genotypes. Detailed screening for R-N and R-L BAVs should be performed for a better understanding of the relationships between these BAV morphologic phenotypes and other heart disease.
More postings on this subject
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