Evolutionary Aspects of Chamber Formation and Septation.

The formed hearts of vertebrates are widely different in anatomy and performance, yet their embryonic hearts are surprisingly similar. Developmental and molecular biology are making great advances in reconciling these differences by revealing an evolutionarily conserved building plan to the vertebrate heart. This suggests that perspectives from evolution may improve our understanding of the formation of the human heart.

Comment on "Exceptional preservation of organs in Devonian placoderms from the Gogo lagerstätte".

Trinajstic et al., (, 16 September 2022, p. 1311-1314) describe exceptionally well-preserved organs in fossilized Devonian placoderms to infer the early evolution of the vertebrate heart.

Equal force generation potential of trabecular and compact wall ventricular cardiomyocytes.

Trabecular myocardium makes up most of the ventricular wall of the human embryo. A process of compaction in the fetal period presumably changes ventricular wall morphology by converting ostensibly weaker trabecular myocardium into stronger compact myocardium. Using developmental series of embryonic and fetal humans, mice and chickens, we show ventricular morphogenesis is driven by differential rates of growth of trabecular and compact layers rather than a process of compaction.

Congenital systemic arteriovenous fistulas: Interventional strategies and embryological perspectives.

Background: Data on congenital systemic arteriovenous fistulas are largely based on individual case reports. A true systemic arteriovenous fistula needs to be differentiated from other vascular malformations like capillary or venous hemangiomas, which are far more common.

Objectives: We sought to identify the varied symptoms, diagnostic challenges, describe interventional treatment options, and postulate an embryological basis for this uncommonly described entity.

Virtual and augmented reality: New tools for visualizing, analyzing, and communicating complex morphology.

Virtual and augmented reality (VR/AR) are new technologies with the power to revolutionize the study of morphology. Modern imaging approaches such as computed tomography, laser scanning, and photogrammetry have opened up a new digital world, enabling researchers to share and analyze morphological data electronically and in great detail. Because this digital data exists on a computer screen, however, it can remain difficult to understand and unintuitive to interact with.

Quantified growth of the human embryonic heart.

The size and growth patterns of the components of the human embryonic heart have remained largely undefined. To provide these data, three-dimensional heart models were generated from immunohistochemically stained sections of ten human embryonic hearts ranging from Carnegie stage 10 to 23. Fifty-eight key structures were annotated and volumetrically assessed.

An Appreciation of Anatomy in the Molecular World.

Robert H. Anderson is one of the most important and accomplished cardiac anatomists of the last decades, having made major contributions to our understanding of the anatomy of normal hearts and the pathologies of acquired and congenital heart diseases. While cardiac anatomy as a research discipline has become largely subservient to molecular biology, anatomists like Professor Anderson demonstrate anatomy has much to offer.

Identification of the building blocks of ventricular septation in monitor lizards (Varanidae).

Among lizards, only monitor lizards (Varanidae) have a functionally divided cardiac ventricle. The division results from the combined function of three partial septa, which may be homologous to the ventricular septum of mammals and archosaurs. We show in developing monitors that two septa, the 'muscular ridge' and 'bulbuslamelle', express the evolutionarily conserved transcription factors , and , orthologues of which mark the mammalian ventricular septum.

Sinus venosus incorporation: contentious issues and operational criteria for developmental and evolutionary studies.

The sinus venosus is a cardiac chamber upstream of the right atrium that harbours the dominant cardiac pacemaker. During human heart development, the sinus venosus becomes incorporated into the right atrium. However, from the literature it is not possible to deduce the characteristics and importance of this process of incorporation, due to inconsistent terminology and definitions in the description of multiple lines of evidence.

Evolution and Development of the Atrial Septum.

The complete division of the atrial cavity by a septum, resulting in a left and right atrium, is found in many amphibians and all amniotes (reptiles, birds, and mammals). Surprisingly, it is only in eutherian, or placental, mammals that full atrial septation necessitates addition from a second septum. The high incidence of incomplete closure of the atrial septum in human, so-called probe patency, suggests this manner of closure is inefficient.

Morpho-functional characterization of the systemic venous pole of the reptile heart.

Mammals evolved from reptile-like ancestors, and while the mammalian heart is driven by a distinct sinus node, a sinus node is not apparent in reptiles. We characterized the myocardial systemic venous pole, the sinus venosus, in reptiles to identify the dominant pacemaker and to assess whether the sinus venosus remodels and adopts an atrium-like phenotype as observed in mammals. Anolis lizards had an extensive sinus venosus of myocardium expressing Tbx18.

An interactive three-dimensional digital atlas and quantitative database of human development.

Current knowledge about human development is based on the description of a limited number of embryonic specimens published in original articles and textbooks, often more than 100 years ago. It is exceedingly difficult to verify this knowledge, given the restricted availability of human embryos. We created a three-dimensional digital atlas and database spanning the first 2 months of human development, based on analysis of nearly 15,000 histological sections of the renowned Carnegie Collection of human embryonic specimens.

Excessive trabeculations in noncompaction do not have the embryonic identity.

Background: Ventricular noncompaction is characterized by excessive trabeculations and is associated with heart failure. The lesion is hypothesized to result from failed compaction and thus retention of embryonic trabeculations. Here, we assess for the first time the identity of trabeculations in noncompaction to test whether noncompacted hearts show retention of embryonic trabeculations.

The hypertrabeculated (noncompacted) left ventricle is different from the ventricle of embryos and ectothermic vertebrates.

Ventricular hypertrabeculation (noncompaction) is a poorly characterized condition associated with heart failure. The condition is widely assumed to be the retention of the trabeculated ventricular design of the embryo and ectothermic (cold-blooded) vertebrates. This assumption appears simplistic and counterfactual.

Structure and function of the hearts of lizards and snakes.

With approximately 7000 species, snakes and lizards, collectively known as squamates, are by far the most species-rich group of reptiles. It was from reptile-like ancestors that mammals and birds evolved and squamates can be viewed as phylogenetically positioned between them and fishes. Hence, their hearts have been studied for more than a century yielding insights into the group itself and into the independent evolution of the fully divided four-chambered hearts of mammals and birds.

Association between C677T polymorphism of methylene tetrahydrofolate reductase and congenital heart disease: meta-analysis of 7697 cases and 13,125 controls.

Background: Association between the C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene and congenital heart disease (CHD) is contentious.

Methods And Results: We compared genotypes between CHD cases and controls and between mothers of CHD cases and controls. We placed our results in context by conducting meta-analyses of previously published studies.

Development of the hearts of lizards and snakes and perspectives to cardiac evolution.

Birds and mammals both developed high performance hearts from a heart that must have been reptile-like and the hearts of extant reptiles have an unmatched variability in design. Yet, studies on cardiac development in reptiles are largely old and further studies are much needed as reptiles are starting to become used in molecular studies. We studied the growth of cardiac compartments and changes in morphology principally in the model organism corn snake (Pantherophis guttatus), but also in the genotyped anole (Anolis carolinenis and A.

Genome-wide association study of multiple congenital heart disease phenotypes identifies a susceptibility locus for atrial septal defect at chromosome 4p16.

We carried out a genome-wide association study (GWAS) of congenital heart disease (CHD). Our discovery cohort comprised 1,995 CHD cases and 5,159 controls and included affected individuals from each of the 3 major clinical CHD categories (with septal, obstructive and cyanotic defects). When all CHD phenotypes were considered together, no region achieved genome-wide significant association.

Development of the human heart.

Molecular and genetic studies around the turn of this century have revolutionized the field of cardiac development. We now know that the primary heart tube, as seen in the early embryo contains little more than the precursors for the left ventricle, whereas the precursor cells for the remainder of the cardiac components are continuously added, to both the venous and arterial pole of the heart tube, from a single center of growth outside the heart. While the primary heart tube is growing by addition of cells, it does not show significant cell proliferation, until chamber differentiation and expansion starts locally in the tube, by which the chambers balloon from the primary heart tube.

Development of the human aortic arch system captured in an interactive three-dimensional reference model.

Variations and mutations in the human genome, such as 22q11.2 microdeletion, can increase the risk for congenital defects, including aortic arch malformations. Animal models are increasingly expanding our molecular and genetic insights into aortic arch development.