Clin Anat. 2010 Apr;23(3):297-303. doi: 10.1002/ca.20930.
Fetal development of the retrohepatic inferior vena cava and accessory hepatic veins: Re-evaluation of the Alexander Barry's hypothesis.
Jin ZW, Cho BH, Murakami G, Fujimiya M, Kimura W, Yu HC.
Dept. of Surgery, Chonbuk National University Medical School, Jeonju, South Korea.
Abstract
The retrohepatic inferior vena cava (IVC) is commonly considered to originate from the right vitelline or omphalomesenteric vein. In contrast, Alexander Barry hypothesized that one of the hepatic veins grows to merge with the subcardinal vein and develops into the retrohepatic IVC. We re-examined fetal development of the retrohepatic IVC and other related veins using serial histological sections of 20 human fetuses between 6 and 16 weeks of gestation. At 6-7 weeks, when a basic configuration of the portal-hepatic vein systems had just been established, one of hepatic veins (i.e., the posterocaudal vein in the present study) had grown caudally to reach the posterocaudal surface of the liver, and notably, extended into the primitive right adrenal gland (five of the eight early-staged fetuses). Because the inferior right hepatic vein (IRHV) and retrohepatic IVC appeared at the same developmental stage, it is likely that any peripheral remnants of the posterocaudal vein would continue to function as primary drainage territory for the IRHV. The caudate vein developed rapidly in accordance with marked caudal and leftward extension of Spiegel's lobe at 12-16 weeks. Thin accessory hepatic veins developed later than the caudate vein and IRHV. The present results supported Barry's hypothesis.
Showing posts with label Development. Show all posts
Showing posts with label Development. Show all posts
Saturday, December 15, 2012
Thursday, February 3, 2011
Bicuspid Aortic Valve: Two developmentally-distinct types!
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.
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Wednesday, November 3, 2010
Bicuspid Aortic Valve - Etiology and Associated Lesions
The following letter to the editor highlights other articles that deal with different etiologies for different morphologies of bicuspid aortic valve. Worth reading them all!
Alexander R. Opotowsky, MD, MPH* andMichael J. Landzberg, MD
We read with interest and appreciation 3 recent papers in the Journal on the bicuspid aortic valve (BAV).
| J Am Coll Cardiol, 2010; 56:1680, doi:10.1016/j.jacc.2010.03.073 Bicuspid Aortic Valve Morphology |
* Children's Hospital Boston, Boston Adult Congenital Heart Service, Department of Cardiology, 300 Longwood Avenue, Boston, Massachusetts 02115 (Email:alexander.opotowsky@childrens.harvard.edu).
We read with interest and appreciation 3 recent papers in the Journal on the bicuspid aortic valve (BAV).
Fernandez et al. (1) describe distinct developmental patterns for mice and hamsters with right-noncoronary and right-left coronary cusp fusion, respectively. Incredibly, William Osler anticipated, within the limitations of his era, these findings and their significance more than a century ago:
If it turns out to be correct ... that the affected valves are usually those behind ... the coronary arteries ... this would point to some error associated especially with the development of these cusps. It would appear from the observations of Tonge, that two of the segments are formed before the division of the primitive truncus arteriosus is complete, while the third arises laterafter the pulmonary artery and the aorta have divided. It is not at all improbable that we may have here a clew to an explanation of this anomaly, but this is conjectural until we have fullerdetails of the process of the development of the sigmoid valves in mammals (2).
As it becomes increasingly apparent that right-noncoronary and right-left coronary cusp fusion are distinct diseases, research reports on the BAV should make this distinction as Osler suggested: "This point [right-left coronary cusp fusion is the most common BAV morphology], previously overlooked, may prove of interest in the etiology, and should be carefully noted in future observations" (2).
Biner et al. (3) report evidence of a bicuspid aortopathy in first-degree relatives of BAV patients, but did not address the relationship of BAV morphology to aortic properties. We would be interested to know whether BAV morphology in the proband modifies the extent of aortic dilation and stiffness in first-degree relatives.
Tzemos et al. (4) provide data suggesting that the BAV is associated with endothelial dysfunction, at least in the presence of aortic dilation. The authors note that three-fourths of the patients in each BAV group had anteroposterior aortic leaflet orientation (presumably right-left coronary cusp fusion), but no data arepresented on the relationship between BAV morphology and the parameters studied. Does BAV morphology influence the relationship among aortic dilation, aortic stiffness, serum matrix metalloproteinaselevels, and endothelial function?
With deepening understanding of the developmental and physiologic aspects of the BAV and its associated diffuse vasculopathy, we believe that it is vital that data be reported to allow detailed inquiry into potential variation between morphologically and likely clinically and developmentally distinct categories of disease.
References:
1. Fernandez B, Duran AC, Fernandez-Gallego T, et al. Biscupid aortic valves with different spatial orientations of the leaflets are distinct etiological entities J Am Coll Cardiol 2009;54:2312-2318.
2. Osler W. The Bicuspid Condition of the Aortic Valves. . Transactions of the Association of American Physicians. Philadelphia: Wm. J. Dornan; 1886. pp. 185-192.
3. Biner S, Rafique AM, et al. Aortopathy is prevalent in relatives of bicuspid aortic valve patients J Am Coll Cardiol 2009;53:2288-2295.
4. Tzemos N, Lyseggen E, Silversides C, et al. Endothelial function, carotid-femoral stiffness, and plasma matrix metalloproteinase-2 in men with bicuspid aortic valve and dilated aorta J Am Coll Cardiol 2010;55:660-668.
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