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Heart Development (heart + development)
Kinds of Heart Development Selected AbstractsThe Effect of Vascular Endothelial Growth Factor on in vitro Embryonic Heart Development in RatsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2004H. Ülger Summary In vitro effects of vascular endothelial growth factor (VEGF) on heart development and total embryonic growth were investigated in 84 rat embryos (obtained from nine pregnant females) at 9.5 days of gestation that were cultured in whole rat serum (WRS), in <30 kDa + >50 kDa serum fractions [retenate (R)], and in R + VEGF. After 24-h culture, the embryos from each group were harvested and divided into two groups. One group was analysed morphologically and biochemically to obtain embryo protein content, the second group was serially sectioned and examined by light microscopy. Morphological score, embryo protein content, somite number and crown-rump length of embryos indicated that embryos cultured in R had significant embryonic retardation, whereas the addition of VEGF to R increased embryonic growth and development. The morphological scores for WRS, R and R + VEGF were 57.7 ± 0.87, 46.6 ± 1.90 and 52.1 ± 0.97, somite numbers were 26.5 ± 0.47, 20.1 ± 0.63 and 24.4 ± 0.46, crown-rump lengths were 3 ± 0.07, 2.4 ± 0.06 and 2.7 ± 0.06 mm, and embryo protein contents were 160.5 ± 7.41, 98.2 ± 4.81 and 141.1 ± 10.96 ,g per embryo, respectively. The results of histological examination of heart development were similar. The hearts of embryos grown in R were unseptated and tubular. The atrioventricular endocardial cushions were incompletely developed. The addition of VEGF to R improved heart development. There were no gross morphological differences in the cardiac development between embryos grown in WRS and R + VEGF. In both groups, development of the muscular interventricular septum had begun. Development of the atrioventricular cushions was also similar in both groups and had caused narrowing of the atrioventricular canals, but the atrial septation was not observed. [source] Cardiosulfa, a Small Molecule that Induces Abnormal Heart Development in Zebrafish, and Its Biological Implications,ANGEWANDTE CHEMIE, Issue 42 2009Sung-Kyun Ko Verändertes Herz: Die Titelverbindung Cardiosulfa wurde mithilfe eines chemogenetischen Phänotyp-zu-Genotyp-Ansatzes identifiziert. Zebrafisch-Embryos, die ihr ausgesetzt sind, haben ein enges, elongiertes Herz innerhalb eines vergrößerten Herzbeutels (siehe Bild; Herz markiert mit grün fluoreszierendem Protein). [source] Second chromosome genes required for heart development in Drosophila melanogasterGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 10 2007Ye Tao Abstract Heart development is an evolutionarily conserved process. The cardiac organ of Drosophila melanogaster is the dorsal vessel, a linear contractile tissue with cellular and morphogenetic similarities to the primitive heart tube formed at an early stage of vertebrate heart formation. Abundant evidence shows comparable intercellular signaling pathways and transcription factor networks are utilized in Drosophila and vertebrates, to specify cardiac progenitor cells and instruct their differentiation and function in forming the mature heart. With this proven conservation in mind, we screened the second chromosome of Drosophila for genetic intervals that harbor additional loci required for normal dorsal vessel morphogenesis. Our studies identified numerous regions, that when deleted, culminated in dorsal vessels with abnormal cell numbers and/or structural properties. Certain of the deficiency intervals were further characterized to identify individual genes essential for proper cardiac organ formation. Our analyses identified eight genes of diverse functions that are needed for dorsal vessel development. Several of these sequences have known vertebrate homologues, further supporting a conserved genetic basis for heart formation in Drosophila and higher eukaryotes. genesis 45:607,617, 2007. © 2007 Wiley-Liss, Inc. [source] Second lineage of heart forming region provides new understanding of conotruncal heart defectsCONGENITAL ANOMALIES, Issue 1 2010Yuji Nakajima ABSTRACT Abnormal heart development causes various congenital heart defects. Recent cardiovascular biology studies have elucidated the morphological mechanisms involved in normal and abnormal heart development. The primitive heart tube originates from the lateral-most part of the heart forming mesoderm and mainly gives rise to the left ventricle. Then, during the cardiac looping, the outflow tract is elongated by the addition of cardiogenic cells from the both pharyngeal and splanchnic mesoderm (corresponding to anterior and secondary heart field, respectively), which originate from the mediocaudal region of the heart forming mesoderm and are later located anteriorly (rostrally) to the dorsal region of the heart tube. Therefore, the heart progenitors that contribute to the outflow tract region are distinct from those that form the left ventricle. The knowledge that there are two different lineages of heart progenitors in the four-chambered heart provides new understanding of the morphological and molecular etiology of conotruncal heart defects. [source] Understanding heart development and congenital heart defects through developmental biology: A segmental approachCONGENITAL ANOMALIES, Issue 4 2005Masahide Sakabe ABSTRACT The heart is the first organ to form and function during development. In the pregastrula chick embryo, cells contributing to the heart are found in the postero-lateral epiblast. During the pregastrula stages, interaction between the posterior epiblast and hypoblast is required for the anterior lateral plate mesoderm (ALM) to form, from which the heart will later develop. This tissue interaction is replaced by an Activin-like signal in culture. During gastrulation, the ALM is committed to the heart lineage by endoderm-secreted BMP and subsequently differentiates into cardiomyocyte. The right and left precardiac mesoderms migrate toward the ventral midline to form the beating primitive heart tube. Then, the heart tube generates a right-side bend, and the d-loop and presumptive heart segments begin to appear segmentally: outflow tract (OT), right ventricle, left ventricle, atrioventricular (AV) canal, atrium and sinus venosus. T-box transcription factors are involved in the formation of the heart segments: Tbx5 identifies the left ventricle and Tbx20 the right ventricle. After the formation of the heart segments, endothelial cells in the OT and AV regions transform into mesenchyme and generate valvuloseptal endocardial cushion tissue. This phenomenon is called endocardial EMT (epithelial-mesenchymal transformation) and is regulated mainly by BMP and TGF,. Finally, heart septa that have developed in the OT, ventricle, AV canal and atrium come into alignment and fuse, resulting in the completion of the four-chambered heart. Altered development seen in the cardiogenetic process is involved in the pathogenesis of congenital heart defects. Therefore, understanding the molecular nature regulating the ,nodal point' during heart development is important in order to understand the etiology of congenital heart defects, as well as normal heart development. [source] Activation of Tolloid-like 1 gene expression by the cardiac specific homeobox gene Nkx2,5DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 4 2009Inna Sabirzhanova Mammalian Tolloid-like 1 (Tll-1) is a pleiotropic metalloprotease that is expressed by a small subset of cells within the precardiac mesoderm and is necessary for proper heart development. Following heart tube formation Tll-1 is expressed by the endocardium and regions of myocardium overlying the region of the muscular interventricular septum. Mutations in Tll-1 lead to embryonic lethality due to cardiac defects. We demonstrate that the Tll-1 promoter contains Nkx2,5 binding sites and that the Tll-1 promoter is activated by and directly binds Nkx2,5. Tll-1 expression is ablated by a dominant negative Nkx2,5 or by mutation of the Nkx2,5 binding sites within the Tll-1 promoter. In vivo, Tll-1 expression is decreased in the hearts of Nkx2,5 knockout embryos when compared with hemizygous and wild-type embryos. These results show that Nkx2,5 is a direct activator of Tll-1 expression and provide insight into the mechanism of the defects found in both the Tll-1 and Nkx2,5 knockout mice. [source] Induction of initial heart ,-actin, smooth muscle ,-actin, in chick pregastrula epiblast: The role of hypoblast and fibroblast growth factor-8DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2008Hiroko Matsui During heart development at the gastrula stage, inhibition of bone morphogenetic protein (BMP) activity affects the heart specification but does not impair the expression of smooth muscle , -actin (SMA), which is first expressed in the heart mesoderm and recruited into initial heart myofibrils. Interaction of tissues between posterior epiblast and hypoblast at the early blastula stage is necessary to induce the expression of SMA, in which Nodal and Chordin are thought to be involved. Here we investigated the role of fibroblast growth factor-8 (FGF8) in the expression of SMA. In situ hybridization and reverse transcription,polymerase chain reaction showed that Fgf8b is expressed predominantly in the nascent hypoblast. Anti-FGF8b antibody inhibited the expression of SMA, cTNT, and Tbx5, which are BMP-independent heart mesoderm/early cardiomyocyte genes, but not Brachyury in cultured posterior blastoderm, and combined FGF8b and Nodal, but neither factor alone induced the expression of SMA in association with heart specific markers in cultured epiblast. Although FGF8b did not induce the upregulation of phospho-Smad2, anti-FGF8b properties suppressed phospho-Smad2 in cultured blastoderm. FGF8b was able to reverse the BMP-induced inhibition of cardiomyogenesis. The results suggest that FGF8b acts on the epiblast synergistically with Nodal at the pregastrula stage and may play a role in the expression of SMA during early cardiogenesis. [source] Platelet-derived growth factor is involved in the differentiation of second heart field-derived cardiac structures in chicken embryosDEVELOPMENTAL DYNAMICS, Issue 10 2009Noortje A.M. Bax Abstract For the establishment of a fully functional septated heart, addition of myocardium from second heart field-derived structures is important. Platelet-derived growth factors (PDGFs) are known for their role in cardiovascular development. In this study, we aim to elucidate this role of PDGF-A, PDGF-C, and their receptor PDGFR-,. We analyzed the expression patterns of PDGF-A, -C, and their receptor PDGFR-, during avian heart development. A spatiotemporal pattern of ligands was seen with colocalization of the PDGFR-,. This was found in second heart field-derived myocardium as well as the proepicardial organ (PEO) and epicardium. Mechanical inhibition of epicardial outgrowth as well as chemical disturbance of PDGFR-, support a functional role of the ligands and the receptor in cardiac development. Developmental Dynamics 238:2658,2669, 2009. © 2009 Wiley-Liss, Inc. [source] The lim domain only protein 7 is important in zebrafish heart developmentDEVELOPMENTAL DYNAMICS, Issue 12 2008Elisabeth B. Ott Abstract The LIM domain only protein 7 (LMO7), a member of the PDZ and LIM domain-containing protein family is a candidate gene with possible roles in embryonic development and breast cancer progression. LMO7 has been linked to actin cytoskeleton organization through nectin/afadin and to cell,cell adhesion by means of E-cadherin/catenin. In addition, LMO7 has been shown to regulate transcription of the nuclear membrane protein Emerin and other muscle relevant genes. In this study, we used in situ hybridization to investigate LMO7 expression during embryonic development in three widely used vertebrate model species: the zebrafish, the chicken and the mouse. Our temporal and spatial gene expression analysis revealed both common and distinct patterns between these species. In mouse and chicken embryos we found expression in the outflow tract, the inflow tract, the pro-epicardial organ and the second heart field, structures highly important in the developing heart. Furthermore, gene knockdown experiments in zebrafish embryos resulted in severe defects in heart development with effects on the conduction system and on heart localization. In summary, we present here the first developmental study of LMO7. We reveal the temporal and spatial expression patterns of this important gene during mouse, chicken and fish development and our findings suggest essential functions for LMO7 during vertebrate heart development. Developmental Dynamics 237:3940,3952, 2008. © 2008 Wiley-Liss, Inc. [source] Patterning the heart, a template for human cardiomyocyte developmentDEVELOPMENTAL DYNAMICS, Issue 7 2006Susana M. Chuva de Sousa Lopes Abstract Although in mice, the dynamics of gene expression during heart development is well characterized, information on humans is scarce due to the limited availability of material. Here, we analyzed the transcriptional distribution of Mlc-2a, Mlc-1v, Mlc-2v, and atrial natriuretic factor (ANF) in human embryonic hearts between 7 and 18 weeks of gestation and in healthy and hypertrophic adult hearts by in situ hybridization and compared expression with that in mice. Strikingly, Mlc-2a, Mlc-1v, and ANF, which are essentially chamber-restricted in mice by mid-gestation, showed a broader distribution in humans. On the other hand, Mlc-2v may prove to be an adequate ventricular marker in humans in contrast to mouse. This study emphasizes the importance of careful comparative human,animal analyses during embryonic development and adulthood, as avoiding erroneous extrapolations may be critical to develop new and successful myocardial replacement therapies. Development Dynamics 235:1994,2002, 2006. © 2006 Wiley-Liss, Inc. [source] Mechanics and function in heart morphogenesisDEVELOPMENTAL DYNAMICS, Issue 2 2005Thomas Bartman Abstract For years, biomechanical engineers have studied the physical forces involved in morphogenesis of the heart. In a parallel stream of research, molecular and developmental biologists have sought to identify the molecular pathways responsible for embryonic heart development. Recently, several studies have shown that these two avenues of research should be integrated to explain how genes expressed in the heart regulate early heart function and affect physical morphogenetic steps, as well as to conversely show how early heart function affects the expression of genes required for morphogenesis. This review combines the perspectives of biomechanical engineering and developmental biology to lay out an integrated view of the role of mechanical forces in heart development. Developmental Dynamics 233:373,381, 2005. © 2005 Wiley-Liss, Inc. [source] Gain of function of Tbx1 affects pharyngeal and heart development in the mouseGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 3 2009Francesca Vitelli Abstract Mammalian development is highly sensitive to Tbx1 gene dosage reduction. Gene function insights can also be learned from increased or ectopic expression. The authors generated a novel mouse transgenic line, named COET, which expresses Tbx1 upon Cre-mediated recombination. The authors crossed this transgenic line with Tbx1Cre animals to activate expression in the Tbx1 -expression domain. Compound mutant COET;Tbx1Cre/+ animals died after birth and showed heart enlargement. At E18.5, compound mutants showed ventricular septal defects and thymic abnormalities. The authors crossed compound mutants into a Tbx1 null background to understand whether this phenotype is caused by gene overdosage. Results showed that gene dosage reduction at the endogenous locus could not rescue heart and thymic defects, although the transgene rescued the loss of function phenotype. Thus, the transgenic phenotype appears to be due to gain of function. Resultant data demonstrate that Tbx1 expression must be tightly regulated to be compatible with normal embryonic development. genesis 47:188,195, 2009. © 2009 Wiley-Liss, Inc. [source] Second chromosome genes required for heart development in Drosophila melanogasterGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 10 2007Ye Tao Abstract Heart development is an evolutionarily conserved process. The cardiac organ of Drosophila melanogaster is the dorsal vessel, a linear contractile tissue with cellular and morphogenetic similarities to the primitive heart tube formed at an early stage of vertebrate heart formation. Abundant evidence shows comparable intercellular signaling pathways and transcription factor networks are utilized in Drosophila and vertebrates, to specify cardiac progenitor cells and instruct their differentiation and function in forming the mature heart. With this proven conservation in mind, we screened the second chromosome of Drosophila for genetic intervals that harbor additional loci required for normal dorsal vessel morphogenesis. Our studies identified numerous regions, that when deleted, culminated in dorsal vessels with abnormal cell numbers and/or structural properties. Certain of the deficiency intervals were further characterized to identify individual genes essential for proper cardiac organ formation. Our analyses identified eight genes of diverse functions that are needed for dorsal vessel development. Several of these sequences have known vertebrate homologues, further supporting a conserved genetic basis for heart formation in Drosophila and higher eukaryotes. genesis 45:607,617, 2007. © 2007 Wiley-Liss, Inc. [source] A novel mutation in the GATA4 gene in patients with Tetralogy of Fallot,,HUMAN MUTATION, Issue 3 2006Georges Nemer Abstract In vertebrates, heart formation which integrates different structures and cell types is a complex process that involves a network of genes regulated by transcription factors. Proper spatiotemporal expression of these factors ensure the highly needed tight control of each step in organogenesis. A mistake at any step from cell-commitment to valve formation will have a major impact on heart morphogenesis and function leading to congenital heart disease (CHD). Cardiac abnormalities occur with an incidence of one per 100 live births and represent 25% of all congenital malformations. As an alternative approach to linkage-analysis of familial cases of CHD, we started screening familial and sporadic cases of CHDs in a highly consanguineous population for mutations in genes encoding cardiac-enriched transcription factors. The evolutionarily conserved role of these proteins in cardiac development suggested a role in CHD. In this study, we report a mutation in the gene encoding GATA4, one of the earliest markers of heart development. This mutation was found in two out of 26 patients with Tetralogy of Fallot (TOF), and in none of the 94 patients with different phenotypes included in the study, nor in 223 healthy individuals. The heterozygous mutation results in an amino acid substitution in the first zinc finger of GATA4 that reduced its transcriptional activation of downstream target genes, without affecting GATA4 ability to bind DNA, nor its interaction with ZFPM2. © 2006 Wiley-Liss, Inc. [source] Developmental expression and differential cellular localization of obscurin and obscurin-associated kinase in cardiac muscle cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2008Andrei B. Borisov Abstract Obscurin and obscurin-associated kinase are two products of the obscurin transcriptional unit that encodes a recently identified giant muscle-specific protein obscurin. In this study, we characterized the developmental expression and cellular localization of obscurin and obscurin-associated kinase in cardiac muscle cells. We cloned murine obscurin-associated kinase and found that it is abundantly expressed in the heart as two isotypes encoded by 2.2 and 4.9 kb sequences. The 2.2 kb isotype of the kinase was more prominently expressed than the 4.9 kb isotype. Both obscurin and the kinase-like domains were progressively upregulated since the early stages of cardiac development. Obscurin-associated kinase was expressed at higher levels than obscurin at early stages of cardiomyogenesis. Increasing intensity of obscurin expression in the developing heart positively correlated with progressive cell differentiation and was higher in the ventricles compared to the atria. These data were supported by the results of experiments with primary cardiac cell cultures. Obscurin localization changed from a weakly immunopositive diffuse pattern in poorly differentiated cells to an intensely immunolabeled cross-striated distribution at the level of mid-A-bands and Z-disks during the assembly of the myofibrillar contractile apparatus. In dividing myocytes, unlike the interphase cells, obscurin translocated from disassembling myofibrils into a diffuse granulated pattern segregated separately from ,-actinin-immunopositive aggregates. Obscurin-associated kinase was localized mainly to cell nuclei with increasing incorporation into the Z-disks during differentiation. Our results suggest that these two novel proteins are involved in the progression of cardiac myogenesis during the transition to advanced stages of heart development. J. Cell. Biochem. 103: 1621,1635, 2008. © 2007 Wiley-Liss, Inc. [source] Molecular and immunohistochemical analyses of cardiac troponin T during cardiac development in the Mexican axolotl, Ambystoma mexicanumJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2007C. Zhang Abstract The Mexican axolotl, Ambystoma mexicanum, is an excellent animal model for studying heart development because it carries a naturally occurring recessive genetic mutation, designated gene c, for cardiac nonfunction. The double recessive mutants (c/c) fail to form organized myofibrils in the cardiac myoblasts resulting in hearts that fail to beat. Tropomyosin expression patterns have been studied in detail and show dramatically decreased expression in the hearts of homozygous mutant embryos. Because of the direct interaction between tropomyosin and troponin T (TnT), and the crucial functions of TnT in the regulation of striated muscle contraction, we have expanded our studies on this animal model to characterize the expression of the TnT gene in cardiac muscle throughout normal axolotl development as well as in mutant axolotls. In addition, we have succeeded in cloning the full-length cardiac troponin T (cTnT) cDNA from axolotl hearts. Confocal microscopy has shown a substantial, but reduced, expression of TnT protein in the mutant hearts when compared to normal during embryonic development. J. Cell. Biochem. 100: 1,15, 2007. © 2006 Wiley-Liss, Inc. [source] Regulation of dHAND protein expression by all- trans retinoic acid through ET-1/ETAR signaling in H9c2 cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2006Weixin Li Abstract dHAND is thought to be a cardiac-restricted transcription factor during embryonic development. Vertebrate heart development involves many transcription factors such as Nkx2.5, GATA, and tbx5. All- trans retinoic acid (AtRA), the oxidative metabolite of vitamin A, can regulate the expression of these factors to affect embryonic heart development. However, the action of atRA on the expression of dHAND is rarely reported. To clarify whether atRA regulate the dHAND expression, we exposed cultured H9c2 cells (rat embryonic cardiomyocytes) to atRA and detected the protein expression of dHAND by Western blot analysis. We observed atRA can regulate the dHAND expression in a dose- and time-dependent manner. AtRA also inhibited endothelin-1 (ET-1) expression in a time-dependent manner. Further studies revealed that pretreatment with 10 µM BQ-123, a selective endothelin-1 receptor (ETAR) antagonist, for 2 h can significantly counteract the inhibition of 5 µM atRA treatment for 2 h of dHAND mRNA and protein expression. Taken together, these results suggest that atRA regulates dHAND expression by ET-1/ETAR signal transduction pathway in H9c2 cells. The mechanism of ET-1/ETAR signaling in controlling the level of dHAND protein is to reduce the levels of dHAND mRNA. It is possible for atRA to exert its cardiac teratogenesis during vertebrate embryonic development in this way. J. Cell. Biochem. 99: 478,484, 2006. © 2006 Wiley-Liss, Inc. [source] Transient Expression of NMDA Receptor Subunit NR2B in the Developing Rat HeartJOURNAL OF NEUROCHEMISTRY, Issue 6 2000Silke Seeber Abstract: NMDA receptors represent a subtype of the ionotropicglutamate receptor family, comprising three classes of subunits (NR1, NR2A-D,NR3), which exhibit distinct patterns of regional and developmental expressionin the CNS. Recently, some NMDA receptor subunits have also been described inadult extraneuronal tissues and keratinocytes. However, their developmentalexpression patterns are currently unknown. With use of RT-PCR and western blotanalysis, the expression of NMDA receptor subunit NR2B was investigated in thedeveloping rat heart. NR2B mRNA and protein were detected in heart tissue ofrats from embryonic day 14 until postnatal day 21 but disappeared 10 weeksafter birth. In contrast, no NMDA receptor subunit NR1,,-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor subunitGluR2, or anchoring postsynaptic density protein-95 could be detected in ratheart at any developmental stage. Confocal microscopy of cultured cardiacmyocytes (CMs) from neonatal rats revealed distinct NR2B staining mainly ofintracellular structures. However, no functional NMDA receptor could bedetected on CMs by whole-cell recordings. In conclusion, high concentrationsof NR2B protein can be detected in early rat heart development, but itsfunction still remains elusive. [source] Structural and Functional Effects of Developmental Exposure to Ethanol on the Zebrafish HeartALCOHOLISM, Issue 6 2010Cynthia A. Dlugos Background:, Fetal alcohol exposure during development results in a host of cardiac abnormalities including atrial and ventricular septal defects, teratology of Fallot, d-transposition of the great arteries, truncus arteriosus communis, and aortico-pulmonary window. The mechanisms behind these ethanol-induced deficits are unknown. The purpose of this study was to determine whether the zebrafish, a simple model in which heart development and the sequence of gene expression is well elucidated and comparable to that in higher vertebrates, is sensitive to developmental exposure of pharmacologically relevant concentrations of ethanol. Methods:, Zebrafish eggs of the AB strain were raised in egg water or in 0.5% (v/v) ethanol solution for either 54 hpf (hours postfertilization) or 72 hpf. Heart pathology and volumes were evaluated on the latter group at 5 dpf (days postfertilization) on tissue sections from fixed larvae embedded in glycolmethacrylate. Heart rates were determined in embryos of 54 hpf and larvae of 5 dpf. The functional maturity of the heart's conducting system was measured by determining the response of ethanol-treated and control embryos and larvae to the adrenergic agonist, isoproterenol, and the cholinergic agonist, carbachol. Results:, Ethanol-induced alterations occurred in heart morphology and heart volume. A developmental lag in the isoproterenol response and the absence of carbachol-mediated bradycardia were also observed following ethanol treatment. Conclusions:, These results show that exposure of the zebrafish to ethanol during development results in structural and functional changes in the heart that mimic malformations that occur in patients with fetal alcohol syndrome (FAS). These findings promote the zebrafish heart as a future model for investigating the mechanisms responsible for ethanol's adverse effects on vertebrate heart development. [source] Expression of brain natriuretic peptide in the rat heart studies during heart growth and in relation to sympathectomyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2004Magnus Hansson Abstract Brain natriuretic peptide (BNP) might be of importance during heart development and is described to be increasingly expressed in congestive heart failure and to affect the progress of this condition. However, details in the normal expression of BNP are still unclear in various parts of the adult and growing heart, including the conduction system. In this study, we investigated the expression of BNP in relation to that of atrial natriuretic peptide (ANP) in the growing as well as in the adult rat heart. The effects of chemical sympathectomy in adult rats were also examined. Contrary to previous BNP immunohistochemical studies, the BNP antiserum was preabsorbed with an excess of ANP before staining to abolish the crossreactivity with ANP. There was a pronounced BNP immunoreaction in the auricles, the trabeculated ventricular walls, and the peripheral parts of the conduction system at 0,1 days postnatally. The degree of immunoreaction gradually decreased with increasing age. A similar developmental pattern was seen concerning ANP expression, but the magnitude of the latter clearly exceeded that for BNP. Immunoreaction for BNP was never detected in the atrioventricular (AV) node and AV bundle at any stage. In contrast to the situation for ANP previously observed, no obvious changes in BNP immunoreaction patterns were observed in response to sympathectomy. This is the first study to thoroughly demonstrate the expression of BNP in the various regions of the rat heart during growth and in the normal and sympathectomized adult stage. The observations are related to possible functions of natriuretic peptides in the growing and adult heart. Microsc. Res. Tech. 64:30,42, 2004. © 2004 Wiley-Liss, Inc. [source] Cell death and differentiation in the development of the endocardial cushion of the embryonic heartMICROSCOPY RESEARCH AND TECHNIQUE, Issue 5 2002Eltyeb Abdelwahid Abstract The transformation of the endocardial cushion into valves and septa is a critical step in cardiac morphogenesis as it initiates the development of the four-chambered heart. This transformation results from a region-specific balance between cellular proliferation, apoptosis, and differentiation. The development of the form and structure of the endocardial cushion is accompanied by precise patterns of abundant cell death having the morphological features of programmed cell death (apoptosis), which plays an important role in the elimination of redundant cells and in changes of phenotypic composition during histogenesis. Apoptosis is an essential process in morphogenesis as it balances mitosis in renewing tissues. It is controlled by one or more genetic programs that kill the targeted cell. However, the causes, role, and regulation of apoptosis in the developing endocardial cushion still remain to be determined. The clarification of the role of the apoptosis regulatory genes constitutes a major task in future studies of cell death in the developing heart. This new molecular histology of heart development awaits further experiments to clarify the interactive mechanisms that act to ensure the sculpting of the endocardial cushion into valves and septa by determining the size of the cushion cell populations. The relation between the expression of different factors and the modifications of the cushion region during cardiac development are reviewed. In addition, we review and summarize information on molecules identified in our experiments that imply the activity of a number of essential genes coinciding with the key steps in generating the overall architecture of the heart. We correlate their temporal and spatial expression with their proposed roles. Microsc. Res. Tech. 58:395,403, 2002. © 2002 Wiley-Liss, Inc. [source] Non-invasive tracking of avian development in vivo by MRINMR IN BIOMEDICINE, Issue 4 2009Bianca Hogers Abstract Conventional microscopic techniques, to study embryonic development, require large numbers of embryos and are invasive, making follow-up impossible. We explored the use of in vivo MRI to study embryonic development, in general, and cardiovascular development in particular, over time. Wild-type quail embryos (n,=,11) were imaged at embryonic days 3, 5, 7, 9, and 11, covering the main time course of embryonic heart development. On each imaging day cardiac morphology was evaluated and embryonic length was measured. MRI-embryos as well as control embryos (n,=,11) were sacrificed at day 11 and scored for external malformations, while embryonic wet weight and stage were determined. In addition, venous clipped embryos (n,=,4), known to develop cardiovascular malformations, were scanned at regular intervals and sacrificed at day 9 for histological analysis ex vivo. We were able to follow heart development of individual quail embryos inside their shell non-invasively over time, with sufficient detail to study cardiac morphology in vivo. We did not find any adverse effect of the repeated MRI examinations on morphology, length, or weight. Prenatally diagnosed malformations, like ventricular septal defects and aortic arch interruptions were confirmed by histology. In conclusion, micro-MRI can be used to evaluate in vivo early embryonic development and to diagnose cardiovascular malformations prenatally. Copyright © 2008 John Wiley & Sons, Ltd. [source] Expression pattern of neuronal and skeletal muscle voltage-gated Na+ channels in the developing mouse heartTHE JOURNAL OF PHYSIOLOGY, Issue 3 2005Volker Haufe In the mammalian heart, a variety of voltage-gated Na+ channel transcripts and proteins have been detected. However, little quantitative information is available on the abundance of each transcript during development, or the contribution of TTX-sensitive Na+ channels to the cardiac sodium current (INa). Using competitive and real-time RT-PCR we investigated the transcription of six Na+ channels (Nav1.1,Nav1.6) and the ,1 subunit during mouse heart development. Nav1.5 was predominantly expressed in the adult heart, whereas the splice variant Nav1.5a was the major Na+ channel isoform in embryonic hearts. The TTX-resistant Na+ channel transcripts (Nav1.5 and Nav1.5a) increased 1.7-fold during postnatal development. Transcripts encoding TTX-sensitive Na+ channels (Nav1.1,Nav1.4) and the ,1 subunit gradually increased up to fourfold from postnatal day (P)1 to P126, while the Nav1.6 transcript level remained low and constant over the same period. In adults, TTX-sensitive channel mRNA accounted for 30,40% of the channel pool in whole-heart preparations (Nav1.3 > Nav1.4 > Nav1.2 , Nav1.1 , Nav1.6), and 16% in mRNA from isolated cardiomyocytes (Nav1.4 > Nav1.3 > Nav1.2 > Nav1.1 > Nav1.6). Confocal immunofluorescence on ventricular myocytes suggested that Nav1.1 and Nav1.2 were localized at the intercalated disks and in the t tubules. Nav1.3 labelling predominantly produced a diffuse but strong intracellular signal. Nav1.6 fluorescence was detected only along the Z lines. Electrophysiological recordings showed that TTX-sensitive and TTX-resistant Na+ channels, respectively, accounted for 8% and 92% of the INa in adult ventricular cardiomyocytes. Our data suggest that neuronal and skeletal muscle Na+ channels contribute to the action potential of cardiomyocytes in the adult mammalian heart. [source] The Effect of Vascular Endothelial Growth Factor on in vitro Embryonic Heart Development in RatsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2004H. Ülger Summary In vitro effects of vascular endothelial growth factor (VEGF) on heart development and total embryonic growth were investigated in 84 rat embryos (obtained from nine pregnant females) at 9.5 days of gestation that were cultured in whole rat serum (WRS), in <30 kDa + >50 kDa serum fractions [retenate (R)], and in R + VEGF. After 24-h culture, the embryos from each group were harvested and divided into two groups. One group was analysed morphologically and biochemically to obtain embryo protein content, the second group was serially sectioned and examined by light microscopy. Morphological score, embryo protein content, somite number and crown-rump length of embryos indicated that embryos cultured in R had significant embryonic retardation, whereas the addition of VEGF to R increased embryonic growth and development. The morphological scores for WRS, R and R + VEGF were 57.7 ± 0.87, 46.6 ± 1.90 and 52.1 ± 0.97, somite numbers were 26.5 ± 0.47, 20.1 ± 0.63 and 24.4 ± 0.46, crown-rump lengths were 3 ± 0.07, 2.4 ± 0.06 and 2.7 ± 0.06 mm, and embryo protein contents were 160.5 ± 7.41, 98.2 ± 4.81 and 141.1 ± 10.96 ,g per embryo, respectively. The results of histological examination of heart development were similar. The hearts of embryos grown in R were unseptated and tubular. The atrioventricular endocardial cushions were incompletely developed. The addition of VEGF to R improved heart development. There were no gross morphological differences in the cardiac development between embryos grown in WRS and R + VEGF. In both groups, development of the muscular interventricular septum had begun. Development of the atrioventricular cushions was also similar in both groups and had caused narrowing of the atrioventricular canals, but the atrial septation was not observed. [source] Evidence by Expression Analysis of Candidate Genes for Congenital Heart Defects in the NF1 Microdeletion IntervalANNALS OF HUMAN GENETICS, Issue 5 2005M. Venturin Summary It was recently reported that congenital heart disease is significantly more frequent in patients with NF1 microdeletion syndrome than in those with classical NF1. The outcome of congenital heart disease in this subset of patients is likely caused by the haploinsufficiency of gene/s in the deletion interval. Following in silico analysis of the deleted region, we found two genes known to be expressed in adult heart, the Joined to JAZF1 (SUZ12) and the Centaurin-alpha 2 (CENTA2) genes, and seven other genes with poorly defined patterns of expression and function. With the aim of defining their expression profiles in human fetal tissues (15th,21st weeks of gestation), expression analysis by RT-PCR and Northern blotting was performed. C17orf40, SUZ12 and CENTA2 were found to be mainly expressed in fetal heart, and following RT-PCR on mouse embryos and embryonic heart and brain at different stages of development, we found that the orthologous genes C17orf40, Suz12 and Centa2 are also expressed in early stages of development, before and during the formation of the four heart chambers. The presence of binding sites for Nkx2-5, a transcription factor expressed early in heart development, in all three mouse orthologous genes was predicted by bioinformatics, thus reinforcing the hypothesis that these genes might be involved in heart development and may be plausible candidates for congenital heart disease. [source] Periconceptional nutrient intakes and risks of conotruncal heart defects,BIRTH DEFECTS RESEARCH, Issue 3 2010Gary M. Shaw Abstract BACKGROUND Few inquiries into periconceptional nutrition, other than folate, and risk of heart defects exist. We investigated the observed association between conotruncal heart defects and periconceptional vitamin use, as well as potential associations with other dietary nutrients. METHODS Data derived from a population-based, case-control study of fetuses and liveborn infants among California births between July 1999 and June 2004; 76% of eligible case mothers and 77% of eligible control mothers were interviewed. Cases included 140 with d-transposition of great arteries (dTGA), and 163 with tetralogy of Fallot (TOF). Total number of controls was 698. Use of vitamins was elicited by questionnaire for the periconceptional period. Dietary nutrient intake was elicited by a well-known food frequency questionnaire. RESULTS The odds ratio for dTGA associated with supplemental vitamin use was 1.0 (95% confidence interval [CI], 0.7,1.5) and for TOF was 0.9 (95% CI, 0.6,1.3). We observed increased risks associated with lower dietary intakes of linoleic acid, total carbohydrate, and fructose for dTGA, whereas decreased risks were observed for lower intakes of total protein and methionine for TOF. Lower dietary intake of several micronutrients,namely folate, niacin, riboflavin, and vitamins B12, A, and E, even after simultaneous adjustment for other studied nutrients,was associated with increased risk of dTGA but not TOF. These associations were observed among women who did not use vitamin supplements periconceptionally. Analytic consideration of several potential confounders did not reveal alternative interpretations of the results. CONCLUSION Evidence continues to accumulate to show that nutrients, particularly folate, influence risks of structural birth defects. Our results extend observations that other nutrients may also be important in heart development. Birth Defects Research (Part A), 2010. © 2010 Wiley-Liss, Inc. [source] Hypoglycemia induced changes in cell death and cell proliferation in the organogenesis stage embryonic mouse heartBIRTH DEFECTS RESEARCH, Issue 3 2004Gautam S. Ghatnekar Abstract BACKGROUND Hypoglycemia is a side effect of diabetes therapy and causes abnormal heart development. Embryonic heart cells are largely resistant to teratogen-induced apoptosis. METHODS Hypoglycemia was tested for effects on cell death and cell proliferation in embryonic heart cells by exposing mouse embryos on embryonic day (E) 9.5 (plug = E0.5) to hypoglycemia (30,50 mg/dl glucose) in vivo or in vitro for 24 hr. Long-term effects of in vivo exposure on conceptus viability were evaluated at E18.5. Cell death was evaluated on E10.5 by: 1) two TUNEL assays in sectioned embryos to demonstrate DNA fragmentation; 2) confocal microscopy in whole embryos stained with Lysotracker; 3) flow cytometry in dispersed heart cells stained for TUNEL and myosin heavy chain (MHC) to quantify and characterize cell type susceptibility; and 4) immunohistochemistry (IHC) and Western analysis in sectioned embryos to evaluate potential involvement of caspase-3 active subunit and p53. Effects on cell proliferation were evaluated by IHC and Western analysis of proliferating cell nuclear antigen (PCNA). RESULTS In vivo hypoglycemic exposure on E9.5 reduced viability in conceptuses examined on E18.5. Hearts examined on E10.5 demonstrated increased TUNEL and Lysotracker staining. In hearts of embryos exposed to hypoglycemia, flow cytometry demonstrated increased TUNEL-positive cells and cells dual-labeled for TUNEL and MHC. Protein expression of caspase-3 active subunit and p53 was increased and PCNA was markedly reduced in hearts of embryos exposed to hypoglycemia. CONCLUSIONS Hypoglycemia reduces embryonic viability, induces significant cell death, and reduces cell proliferation in the E9.5 mouse heart, and these processes may involve active caspase-3 and p53. Birth Defects Research (Part A), 2004. © 2004 Wiley-Liss, Inc. [source] Heparin-binding epidermal growth factor-like growth factor as a novel targeting molecule for cancer therapyCANCER SCIENCE, Issue 5 2006Shingo Miyamoto HB-EGF, a member of the EGF family of growth factors, exerts its biological activity through activation of the EGFR and other ErbB receptors. HB-EGF participates in diverse biological processes, including heart development and maintenance, skin wound healing, eyelid formation, blastocyst implantation, progression of atherosclerosis and tumor formation, through the activation of signaling molecules downstream of ErbB receptors and interactions with molecules associated with HB-EGF. Recent studies have indicated that HB-EGF gene expression is significantly elevated in many human cancers and its expression level in a number of cancer-derived cell lines is much higher than those of other EGFR ligands. Several lines of evidence have indicated that HB-EGF plays a key role in the acquisition of malignant phenotypes, such as tumorigenicity, invasion, metastasis and resistance to chemotherapy. Studies in vitro and in vivo have indicated that HB-EGF expression is essential for tumor formation of cancer-derived cell lines. CRM197, a specific inhibitor of HB-EGF, and an antibody against HB-EGF are both able to inhibit tumor growth in nude mice. These results indicate that HB-EGF is a promising target for cancer therapy, and that the development of targeting tools against HB-EGF could represent a novel type of therapeutic strategy, as an alternative to targeting ErbB receptors. (Cancer Sci 2006; 97: 341,347) [source] | |||||||||||||||||||||||||