Valve cardiaque

Résumé

Une valve cardiaque est un élément du cœur séparant les différentes cavités et empêchant le sang de refluer dans le mauvais sens. Chez les mammifères dont le cœur est composé de quatre cavités, le cœur contient quatre valves :

la valve mitrale entre l'atrium (ou oreillette) gauche et le ventricule gauche ;
la valve tricuspide entre l'atrium (ou oreillette) droit et le ventricule droit ;
la valve aortique entre le ventricule gauche et l'aorte ;
la valve pulmonaire entre le ventricule droit et l'artère pulmonaire.

En cas de dysfonction de l'une de ces valves, peut être mis en place une valve artificielle cardiaque, soit de type mécanique, soit de type bioprothèse. Terminologie Dans le Trésor de la langue française informatisé, il est préconisé l'emploi du mot « valvule », la « valve » étant un composé de cette dernière. La plupart des traités de médecine emploie cependant le terme « valve ». Les dictionnaires spécialisés en médecine préconisent également le terme «

Source officielle

https://fr.wikipedia.org/wiki/Valve_cardiaque

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Publications associées (3)

An extracellular matrix protein microarray to study endothelial to mesenchymal transformation in mitral valve endothelial cells

Blaise Calpe

In the developing heart, a subset of endothelial cells (ECs) undergo a process of endothelial to mesenchymal transformation (EMT) that leads to the remodeling of the cardiac cushions and the formation of the cardiac valves. Understanding how microenvironmental cues regulate EMT has important implication for the treatment of congenital heart valve diseases and for heart valve tissue engineering. Here a set of extracellular matrix (ECM) proteins and growth factors (GF) were tested to determine the extent of regulation of EMT in adult ovine mitral valve endothelial cells (MVECs). Traditional cell culture dishes present limitations on large scale screening of cells-microenvironments interactions. To address this problem, a high throughput cellular microarray platform was developed. Using a contact printer, 84 different combinations of ECM proteins and GF were microarrayed on a modified glass slide. The slides were seeded with MVECs and immunostained against EMT maker alpha smooth muscle actin ([alpha]-SMA). Fluorescence images of each spot of the microarray were taken with a microscope equipped with an automated stage. These images were analyzed with a custom image processing routine developed with CellProfiler to assess the percentage of cells expressing [alpha]-SMA on each ECM combination.

2011

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Partitioning and sorting particles, including molecules, cells and organisms, is an essential prerequisite for a diverse range of applications. Here, we describe a very economical microfluidic platform (built from parts costing about U.S.

6800 for a stand-alone system or U.S.

3700, when mounted on an existing fluorescence microscope connected to a computer) to sort droplets, cells and embryos, based on imaging data. Valves operated by a Braille display are used to open and close microfluidic channels, enabling sorting at rates of >2 Hz. Furthermore, we show microfluidic 8-way sorting for the first time, facilitating the simultaneous separation and collection of objects with diverse characteristics/phenotypes. Due to the high flexibility in the size of objects that can be sorted, the low cost, and the many possibilities enabled by imaging technology, we believe that our approach nicely complements existing FACS and μFACS technology.

2018

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Endothelial Notch1 Is Required for Proper Development of the Semilunar Valves and Cardiac Outflow Tract

Freddy Radtke

Background-Congenital heart disease is the most common type of birth defect, affecting approximate to 2% of the population. Malformations involving the cardiac outflow tract and semilunar valves account for >50% of these cases predominantly because of a bicuspid aortic valve, which has an estimated prevalence of 1% in the population. We previously reported that mutations in NOTCH1 were a cause of bicuspid aortic valve in nonsyndromic autosomal-dominant human pedigrees. Subsequently, we described a highly penetrant mouse model of aortic valve disease, consisting of a bicuspid aortic valve with thickened cusps and associated stenosis and regurgitation, in Notch1-haploinsufficient adult mice backcrossed into a Nos3-null background. Methods and Results-Here, we described the congenital cardiac abnormalities in Notch1(+/-); Nos3(-/-) embryos that led to approximate to 65% lethality by postnatal day 10. Although expected Mendelian ratios of Notch1(+/-); Nos3(-/-) embryos were found at embryonic day 18.5, histological examination revealed thickened, malformed semilunar valve leaflets accompanied by additional anomalies of the cardiac outflow tract including ventricular septal defects and overriding aorta. The aortic valve leaflets of Notch1(+/-); Nos3(-/-) embryos at embryonic day 15.5 were significantly thicker than controls, consistent with a defect in remodeling of the semilunar valve cushions. In addition, we generated mice haploinsufficient for Notch1 specifically in endothelial and endothelial-derived cells in a Nos3-null background and found that Notch1(fl/+); Tie2-Cre(+/-); Nos3(-/-) mice recapitulate the congenital cardiac phenotype of Notch1(+/-); Nos3(-/-) embryos. Conclusions-Our data demonstrate the role of endothelial Notch1 in the proper development of the semilunar valves and cardiac outflow tract.

Wiley-Blackwell2016

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6800 for a stand-alone system or U.S.

2018