A well-developed heart is essential for embryonic survival. There are constant interactions between cardiac tissue motion and blood flow, which determine the heart shape itself. Hemodynamic forces are a powerful stimulus for cardiac growth and differentiation. Therefore, it is particularly interesting to investigate how the blood flows through the heart and how hemodynamics is linked to a particular species and its development, including human. The appropriate patterns and magnitude of hemodynamic stresses are necessary for the proper formation of cardiac structures, and hemodynamic perturbations have been found to cause malformations via identifiable mechanobiological molecular pathways. There are significant differences in cardiac hemodynamics among vertebrate species, which go hand in hand with the presence of specific anatomical structures. However, strong similarities during development suggest a common pattern for cardiac hemodynamics in human adults. In the human fetal heart, hemodynamic abnormalities during gestation are known to progress to congenital heart malformations by birth. In this chapter, we discuss the current state of the knowledge of the prenatal cardiac hemodynamics, as discovered through small and large animal models, as well as from clinical investigations, with parallels gathered from the poikilotherm vertebrates that emulate some hemodynamically significant human congenital heart diseases.
- Klíčová slova
- Axolotl, Chick embryo, DORV, Developing myocardium, ET1, Embryogenesis, Endothelin 1, Fetal heart, Guinea pig, HLHS, Hemodynamics, Hyperplasia, Hypertrophy, Hypoplastic left heart syndrome, KLF2, Krüppel-like factor 2, Lamb, Mouse, NOS3, Nitric oxide synthase 3, Pressure overload, Rat, Reptile, VSD, Volume overload, Zebrafish,
- MeSH
- hemodynamika * fyziologie MeSH
- lidé MeSH
- srdce * růst a vývoj fyziologie MeSH
- vrozené srdeční vady patofyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Recent reports confirmed the notion that there exists a rudimentary cardiac conduction system (CCS) in the crocodylian heart, and development of its ventricular part is linked to septation. We thus analyzed myocardial development with the emphasis on the CCS components and vascularization in two different crocodylian species. RESULTS: Using optical mapping and HNK-1 immunostaining, pacemaker activity was localized to the right-sided sinus venosus. The atrioventricular conduction was restricted to dorsal part of the atrioventricular canal. Within the ventricle, the impulse was propagated from base-to-apex initially by the trabeculae, later by the ventricular septum, in which strands of HNK-1 positivity were temporarily observed. Completion of ventricular septation correlated with transition of ventricular epicardial activation pattern to mature apex-to-base direction from two periapical foci. Despite a gradual thickening of the ventricular wall, no morphological differentiation of the Purkinje network was observed. Thin-walled coronary vessels with endothelium positive for QH1 obtained a smooth muscle coat after septation. Intramyocardial vessels were abundant especially in the rapidly thickening left ventricular wall. CONCLUSIONS: Most of the CCS components present in the homeiotherm hearts can be identified in the developing crocodylian heart, with a notable exception of the Purkinje network distinct from the trabeculae carneae.
- Klíčová slova
- cardiac conduction system, crocodile embryo, heart, optical mapping, septation, vasculogenesis,
- MeSH
- myokard MeSH
- převodní systém srdeční * MeSH
- srdce * fyziologie MeSH
- srdeční komory MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The group Anguimorpha represents one of the most unified squamate clades in terms of body plan, ecomorphology, ecophysiology and evolution. On the other hand, the anguimorphs vary between different habitats and ecological niches. Therefore, we focused on the group Anguimorpha to test a possible correlation between heart morphology and ecological niche with respect to phylogenetic position in Squamata with Sphenodon, Salvator, and Pogona as the outgroups. The chosen lepidosaurian species were investigated by microCT. Generally, all lepidosaurs had two well-developed atria with complete interatrial septum and one ventricle divided by ventricular septa to three different areas. The ventricles of all lepidosaurians had a compact layer and abundant trabeculae. The compact layer and trabeculae were developed in accordance with particular ecological niche of the species, the trabeculae in nocturnal animals with low metabolism, such as Sphenodon, Heloderma or Lanthanotus were more massive. On the other hand athletic animals, such as varanids or Salvator, had ventricle compartmentalization divided by three incomplete septa. A difference between varanids and Salvator was found in compact layer thickness: thicker in monitor lizards and possibly linked to their mammalian-like high blood pressure, and the level of ventricular septation. In summary: heart morphology varied among clades in connection with the ecological niche of particular species and it reflects the phylogenetic position in model clade Anguimorpha. In the absence of fossil evidence, this is the closest approach how to understand heart evolution and septation in clade with different cardiac compartmentalization levels.
- Klíčová slova
- Lanthanotus, Salvator, Sphenodon, Varanus, evolutionary traits, septation, ventricle,
- Publikační typ
- časopisecké články MeSH
BACKGROUND: During amphibian metamorphosis, the crucial moment lies in the rearrangement of the heart, reflecting the changes in circulatory demands. However, little is known about the exact shifts linked with this rearrangement. Here, we demonstrate such myocardial changes in axolotl (Ambystoma mexicanum) from the morphological and physiological point of view. RESULTS: Micro-CT and histological analysis showed changes in ventricular trabeculae organization, completion of the atrial septum and its connection to the atrioventricular valve. Based on Myosin Heavy Chain and Smooth Muscle Actin expression we distinguished metamorphosis-induced changes in myocardial differentiation at the ventricular trabeculae and atrioventricular canal. Using optical mapping, faster speed of conduction through the atrioventricular canal was demonstrated in metamorphic animals. No differences between the groups were observed in the heart rates, ventricular activation times, and activation patterns. CONCLUSIONS: Transition from aquatic to terrestrial life-style is reflected in the heart morphology and function. Rebuilding of the axolotl heart during metamorphosis was connected with reorganization of ventricular trabeculae, completion of the atrial septum and its connection to the atrioventricular valve, and acceleration of AV conduction.
- Klíčová slova
- atrial septation, metamorphosis, micro-CT, optical mapping, trabeculae, ventricular septation,
- MeSH
- Ambystoma mexicanum * fyziologie MeSH
- biologická evoluce MeSH
- biologická proměna fyziologie MeSH
- myokard MeSH
- srdce * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Tissue imaging in 3D using visible light is limited and various clearing techniques were developed to increase imaging depth, but none provides universal solution for all tissues at all developmental stages. In this review, we focus on different tissue clearing methods for 3D imaging of heart and vasculature, based on chemical composition (solvent-based, simple immersion, hyperhydration, and hydrogel embedding techniques). We discuss in detail compatibility of various tissue clearing techniques with visualization methods: fluorescence preservation, immunohistochemistry, nuclear staining, and fluorescent dyes vascular perfusion. We also discuss myocardium visualization using autofluorescence, tissue shrinking, and expansion. Then we overview imaging methods used to study cardiovascular system and live imaging. We discuss heart and vessels segmentation methods and image analysis. The review covers the whole process of cardiovascular system 3D imaging, starting from tissue clearing and its compatibility with various visualization methods to the types of imaging methods and resulting image analysis.
- Klíčová slova
- Biology Experimental Methods, Imaging Methods in Chemistry, Optical Imaging,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The mammalian ventricular myocardium forms a functional syncytium due to flow of electrical current mediated in part by gap junctions localized within intercalated disks. The connexin (Cx) subunit of gap junctions have direct and indirect roles in conduction of electrical impulse from the cardiac pacemaker via the cardiac conduction system (CCS) to working myocytes. Cx43 is the dominant isoform in these channels. We have studied the distribution of Cx43 junctions between the CCS and working myocytes in a transgenic mouse model, which had the His-Purkinje portion of the CCS labeled with green fluorescence protein. The highest number of such connections was found in a region about one-third of ventricular length above the apex, and it correlated with the peak proportion of Purkinje fibers (PFs) to the ventricular myocardium. At this location, on the septal surface of the left ventricle, the insulated left bundle branch split into the uninsulated network of PFs that continued to the free wall anteriorly and posteriorly. The second peak of PF abundance was present in the ventricular apex. Epicardial activation maps correspondingly placed the site of the first activation in the apical region, while some hearts presented more highly located breakthrough sites. Taken together, these results increase our understanding of the physiological pattern of ventricular activation and its morphological underpinning through detailed CCS anatomy and distribution of its gap junctional coupling to the working myocardium.
- Klíčová slova
- cardiac conduction system, connexin, immunohistochemistry, myocardium, optical mapping,
- MeSH
- konexin 43 fyziologie MeSH
- mezerový spoj fyziologie MeSH
- mezibuněčná komunikace * MeSH
- myši MeSH
- perikard cytologie fyziologie MeSH
- Purkyňova vlákna cytologie fyziologie MeSH
- srdeční komory patologie MeSH
- svalové buňky cytologie fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- GJA1 protein, mouse MeSH Prohlížeč
- konexin 43 MeSH
During development, the ventricles of mammals and birds acquire a specialized pattern of electrical activation with the formation of the atrioventricular conduction system (AVCS), which coincides with the completion of ventricular septation. We investigated whether AVCS formation coincides with ventricular septation in developing Siamese crocodiles (Crocodylus siamensis). Comparisons were made with Amazon toadhead turtle (Mesoclemmys heliostemma) with a partial septum only and no AVCS (negative control) and with chicken (Gallus gallus) (septum and AVCS, positive control). Optical mapping of the electrical impulse in the crocodile and chicken showed a similar developmental specialization that coincided with full ventricular septation, whereas in the turtle the ventricular activation remained primitive. Co-localization of neural marker human natural killer-1 (HNK-1) and cardiomyocyte marker anti-myosin heavy chain (MF20) identified the AVCS on top of the ventricular septum in the crocodile and chicken only. AVCS formation is correlated with ventricular septation in both evolution and development.
- Klíčová slova
- Chicken, Crocodile, Embryo, Heart, Turtle,
- MeSH
- aligátoři a krokodýli * MeSH
- kardiomyocyty MeSH
- mezikomorová přepážka * MeSH
- převodní systém srdeční MeSH
- srdeční komory MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The atrial septum enables efficient oxygen transport by separating the systemic and pulmonary venous blood returning to the heart. Only in placental mammals will the atrial septum form by the coming-together of the septum primum and the septum secundum. In up to one of four placental mammals, this complex morphogenesis is incomplete and yields patent foramen ovale. The incidence of incomplete atrial septum is unknown for groups with the septum primum only, such as birds and reptiles. We found a low incidence of incomplete atrial septum in 11 species of bird (0% of specimens) and 13 species of reptiles (3% of specimens). In reptiles, there was a trabecular interface between the atrial septum and the atrial epicardium which was without a clear boundary between left and right atrial cavities. In developing reptiles (four squamates and one crocodylian), the septum primum initiated as a sheet that acquired perforations and the trabecular interface developed late. We conclude that atrial septation from the septum primum only results in a low incidence of incompleteness. In reptiles, the atrial septum and atrial wall develop a trabecular interface, but previous studies on atrial hemodynamics suggest this interface has a very limited capacity for shunting.
- Klíčová slova
- evolution, heart, patent foramen ovale, septation,
- MeSH
- defekty septa síní epidemiologie etiologie MeSH
- incidence MeSH
- plazi abnormality MeSH
- ptáci abnormality MeSH
- síňová přepážka embryologie růst a vývoj patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: In mammals, odontogenesis is regulated by transient signaling centers known as enamel knots (EKs), which drive the dental epithelium shaping. However, the developmental mechanisms contributing to formation of complex tooth shape in reptiles are not fully understood. Here, we aim to elucidate whether signaling organizers similar to EKs appear during reptilian odontogenesis and how enamel ridges are formed. RESULTS: Morphological structures resembling the mammalian EK were found during reptile odontogenesis. Similar to mammalian primary EKs, they exhibit the presence of apoptotic cells and no proliferating cells. Moreover, expression of mammalian EK-specific molecules (SHH, FGF4, and ST14) and GLI2-negative cells were found in reptilian EK-like areas. 3D analysis of the nucleus shape revealed distinct rearrangement of the cells associated with enamel groove formation. This process was associated with ultrastructural changes and lipid droplet accumulation in the cells directly above the forming ridge, accompanied by alteration of membranous molecule expression (Na/K-ATPase) and cytoskeletal rearrangement (F-actin). CONCLUSIONS: The final complex shape of reptilian teeth is orchestrated by a combination of changes in cell signaling, cell shape, and cell rearrangement. All these factors contribute to asymmetry in the inner enamel epithelium development, enamel deposition, ultimately leading to the formation of characteristic enamel ridges.
- Klíčová slova
- Na,K-ATPase, SHH, chameleon, crocodile, enamel ridge, gecko, matriptase, nuclei shape, tooth shape,
- MeSH
- aktiny metabolismus MeSH
- lipidová tělíska metabolismus MeSH
- odontogeneze fyziologie MeSH
- plazi anatomie a histologie růst a vývoj metabolismus MeSH
- transmisní elektronová mikroskopie MeSH
- vývojová regulace genové exprese fyziologie MeSH
- zubní sklovina cytologie metabolismus ultrastruktura MeSH
- zuby MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aktiny MeSH
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 Tbx5, Irx1 and Irx2, orthologues of which mark the mammalian ventricular septum. Compaction of embryonic trabeculae contributes to the formation of these septa. The septa are positioned, however, to the right of the atrioventricular junction and they do not participate in the separation of incoming atrial blood streams. That separation is accomplished by the 'vertical septum', which expresses Tbx3 and Tbx5 and orchestrates the formation of the electrical conduction axis embedded in the ventricular septum. These expression patterns are more pronounced in monitors than in other lizards, and are associated with a deep electrical activation near the vertical septum, in contrast to the primitive base-to-apex activation of other lizards. We conclude that evolutionarily conserved transcriptional programmes may underlie the formation of the ventricular septa of monitors.
- Klíčová slova
- Evolution, Heart, Lizard, Ventricular septum,
- MeSH
- časosběrné zobrazování MeSH
- echokardiografie veterinární MeSH
- embryo nesavčí MeSH
- homeodoménové proteiny genetika fyziologie MeSH
- ještěři embryologie genetika MeSH
- mezikomorová přepážka diagnostické zobrazování embryologie MeSH
- molekulární evoluce MeSH
- proteiny T-boxu genetika fyziologie MeSH
- srdeční komory diagnostické zobrazování embryologie MeSH
- srdeční síně diagnostické zobrazování embryologie MeSH
- těžké řetězce myosinu genetika metabolismus MeSH
- vývojová regulace genové exprese MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- audiovizuální média MeSH
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- homeodoménové proteiny MeSH
- proteiny T-boxu MeSH
- T-box transcription factor 5 MeSH Prohlížeč
- těžké řetězce myosinu MeSH
