Development of the inlet portion of the right ventricle in the embryonic rat heart: The basis for tricuspid valve development

Wenink, Arnold C. G.; Wisse, Bert; Groenendijk, P.M.

doi:10.1002/ar.1092390212

Cited by 12 publications

(8 citation statements)

References 21 publications

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“…Before day 14 of development the volume shows the greatest increase. This period corresponds with the time when the atrio-ventricular canal starts to direct the blood into both the inlet and proximal outlet segments Wenink et al, 1994). As is shown in Figures 8 and 10, the primary fold differs in growth rate from the growth rate of the inlet segment as well as the proximal outlet segment and the growth rate of the total myocardial volume.…”

Section: Primary Foldmentioning

confidence: 88%

“…If this change in growth rate is correlating to cardiovascular changes which reflect increasing blood volume and blood pressure, then typical differentiation processes in specific areas of the developing heart have to be hypothesized. It is remarkable that around day 14 the septation has been reported to have proceeded to such an extent that a separate right blood stream into the outlet is evolving (Wenink et al, 1994). Thus, systolic pressure increases at that time, especially in the ventricles (Van Mierop and Bertuch, 1967).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, in this stage of development the inlet segment is probably the main contraction compartment to supply the embryo with blood. From 13 days onwards the cushions of the atrioventricular canal direct also a part of the bloodflow into the proximal outlet segment through a developing groove from the atrio-ventricular canal into the proximal outlet segment (Wenink et al, 1994). From that time the proximal outlet segment, too, starts to function like a contraction compartment which directs the bloodflow to the distal outlet segment.…”

Section: Sinus Venosus and Sinu-atrial Junctionmentioning

confidence: 99%

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Growth of the myocardial volumes of the individual cardiac segments in the rat embryo

1995

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The timing of the septal volume increase fits with qualitative descriptions of ventricular septation. The atrio-ventricular canal and distal outlet segment have an important constrictive function in early stages, when valves are not yet present. Slow conduction and contraction patterns have been reported to be a characteristic feature of these portions of the embryonic heart. With development of valves these segments are loosing their mechanical function and, thus, their proportional volume declines.

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Section: Primary Foldmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Sinus Venosus and Sinu-atrial Junctionmentioning

confidence: 99%

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Growth of the myocardial volumes of the individual cardiac segments in the rat embryo

1995

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“…The development of the right-ventricular inlet from myocardium between the bundle of His medially and the right bundle branch or septomarginal trabeculation laterally has been hypothesized. 54,55 The present integration of the development of the atrioventricular canal with that of the inlet portion of the ventricles into a single morphogenetic process has made it clear that malformations such as double inlet left ventricle, atrioventricular septal defects, tricuspid atresia, and Ebstein's anomaly should be considered as the lasting consequences of a temporary arrest of normal development. 24,35,41,56 …”

Section: Lamers and Moorman Cardiac Septation 97mentioning

confidence: 99%

Cardiac Septation

Lamers

Moorman

2002

Circulation Research

122

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Heart morphogenesis comprises 2 major consecutive steps, viz. chamber formation followed by septation. Septation is the remodeling of the heart from a single-channel peristaltic pump to a dual-channel, synchronously contracting device with 1-way valves. In the human heart, septation occurs between 4 and 7 weeks of development. Cardiac looping and chamber formation bring the contributing structures into position to engage in septation. Cardiomyocytes that participate in chamber formation do not materially contribute to septation. The (re)discovery of the role of extracardiac mesenchymal tissue in atrioventricular septation, the appreciation that the formation of the right atrioventricular connection is more than a mere rightward expansion of the atrioventricular canal, the awareness that myocardium originating from the so-called anterior heart field regresses after its function as outflow-tract sphincter ceases, and the recent finding that the myocardialized proximal portion of the outflow-tract septum becomes the supraventricular crest have all significantly enhanced our understanding of the morphogenetic processes that contribute to septation. The bifurcation of the ventricular conduction system is the landmark that separates the contribution of the atrioventricular cushions and the outflow-tract ridges to septation and that divides the muscular ventricular septum in inlet, trabecular, and outlet portions.

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“…However, the two segments behave differently in that the distal outlet segment shows a rapid increase of myocyte number between days 13 and 15, whereas the atrio-ventricular canal shows a more gradual increase. This might be explained by the notion that the shift of the atrio-ventricular canal to the right starts already at 13 days (Wenink et al, 1994), whereas the differential growth process that transfers the aorta toward the left (Stalsberg, 1969;Pexieder, 1978) is seen somewhat later in development.…”

Section: Total Number Of Myocytesmentioning

confidence: 99%

Nuclear and cellular size of myocytes in different segments of the developing rat heart

1996

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Background In the embryonic heart, the individual cardiac segments show different growth rates. For the analysis of changing form in relation with changing function, data on number and shape of cardiomyocytes are necessary. Such data will give insight into the process of hypertrophy and/or hyperplasia as they may take place in the myocardium in the embryonic period. Methods We have measured the volumes of the nuclei and myocytes as well as the surface areas of the nuclear envelope and cellular membrane using stereological tools in rat embryos from 11 days postcoitum to 17 days postcoitum. From the data of the cellular volume of the myocytes and the myocardial volume of the individual segments, we have calculated the total number of myocytes during the developmental period. Results It is shown that the sinus venosus, sinu‐atrial junction, and atrium increase their cellular volume during development, whereas the other cardiac segments show no difference in cellular volume. Similarly, the surface area of the cell membrane of the sinus venosus and sinu‐atrial junction had increased during development. The nuclear volume and the surface area of the nuclear envelope did not differ during the period studied. The total number of myocytes showed a conspicuously smaller increase in the atrio‐ventricular canal and distal outlet segment than in the other segments. Conclusions The increase of the cellular volume in the segments sinus venosus and sinu‐atrial junction seems to be due to a late differentiation process. In general, however, the increase of the myocardial volume in the individual cardiac segments is caused by hyperplasia of the cardiomyocytes in these segments and not by hypertrophy. The surface area of cells has a fixed relationship with cell volume, indicating that no important changes take place in the developmental period studied. © 1996 Wiley‐Liss, Inc.

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Development of the inlet portion of the right ventricle in the embryonic rat heart: The basis for tricuspid valve development

Cited by 12 publications

References 21 publications

Growth of the myocardial volumes of the individual cardiac segments in the rat embryo

Growth of the myocardial volumes of the individual cardiac segments in the rat embryo

Cardiac Septation

Nuclear and cellular size of myocytes in different segments of the developing rat heart

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