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Kotsopoulou I, Vyas AK, Cory MJ, Chan CS, Jagarapu J, Gill S, Mudduluru M, Angelis D. Developmental changes of the fetal and neonatal thyroid gland and functional consequences on the cardiovascular system. J Perinatol 2022; 42:1576-1586. [PMID: 36376450 DOI: 10.1038/s41372-022-01559-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/29/2022] [Accepted: 11/01/2022] [Indexed: 11/16/2022]
Abstract
Thyroid hormones play an important role in the development and function of the cardiac myocyte. Dysregulation of the thyroid hormone milieu affects the fetal cardiac cells via complex molecular mechanisms, either by altering gene expression or directly by affecting post-translational processes. This review offers a comprehensive summary of the effects of thyroid hormones on the developing cardiovascular system and its adaptation. Furthermore, we will highlight the gaps in knowledge and provide suggestions for future research.
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Affiliation(s)
- Ioanna Kotsopoulou
- Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Arpita K Vyas
- Division of Pediatrics and Endocrinology, College of Medicine, California Northstate University, Elk Grove, CA, USA
| | - Melinda J Cory
- Division of Cardiology, Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Christina S Chan
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jawahar Jagarapu
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shamaila Gill
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Manjula Mudduluru
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Dimitrios Angelis
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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2
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Sirsat TS, Sirsat SKG, Price ER, Pineda M, Dzialowski EM. Manipulating plasma thyroid hormone levels alters development of endothermy and ventilation in nestling red-winged blackbirds. Front Physiol 2022; 13:1027257. [PMID: 36523554 PMCID: PMC9745037 DOI: 10.3389/fphys.2022.1027257] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/14/2022] [Indexed: 03/14/2024] Open
Abstract
Thyroid hormones are key regulators of development and metabolism in vertebrates. During the nestling period, young of altricial species transition from an ectothermic phenotype to an endothermic phenotype. Red-winged blackbirds are an altricial species that exhibit an increase in plasma 3,3', 5-triiodo-L-thyronine (T3) levels during the first 5 days post-hatch (dph), begin to develop endothermic metabolic responses by 7 dph, and fledge within 10 days of hatching. We propose that thyroid hormones play an important role in regulating development of endothermy during the nestling period in altricial birds. To better understand the effects of thyroid hormones on endothermic metabolic development in an altricial species, we treated nestling red-winged blackbirds on 2, 3, and 5 dph with either methimazole (MMI) to induce hypothyroidism or supplemental T3 to induce hyperthyroidism. We then measured on 5, 7, and 9 dph morphology and whole animal O2 consumption (V ˙ o 2 ) and ventilation in the thermal neutral zone and during gradual cooling. Treatment of nestlings with MMI resulted in lower plasma T3 levels on 5 dph that recovered by 7 dph, while supplementing with T3 did not affect plasma T3 levels on 5, 7 and 9 dph. Treatment with MMI resulted in smaller nestlings with smaller hearts and structural characters such as wing chord and femur length, but larger lungs and kidneys. Treatment with T3 produced smaller nestlings with smaller body masses and shorter femur and tarsus lengths. The development ofV ˙ o 2 and ventilation endothermic responses to gradual cooling in MMI treated nestlings were delayed when compared with control nestlings. In 9 dph nestlings, hypothyroidism resulted in alterations in the responses of ventilation frequency and tidal volume to cooling when compared with the control nestlings. Supplemental T3 had no effect on the development ofV ˙ o 2 and ventilation in the thermal neutral zone or in response to cooling. Our data suggest plasma thyroid hormone levels play an active role in the systemic development of endothermic capacity and the development of ventilatory control. In the nestling avian, multiple systems develop in concert to produce an endothermic phenotype, but reduced thyroid hormone delays maturation of endothermic capacity.
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Affiliation(s)
- Tushar S. Sirsat
- Department of Physician Assistant Studies, Clarkson University, Potsdam, NY, United States
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Sarah K. G. Sirsat
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
- Department of Biology, SUNY Potsdam, Potsdam, NY, United States
| | - Edwan R. Price
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
- Green Godwit Consulting, Cleveland, OH, United States
| | - Megan Pineda
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
- FUJIFILM Diosynth Biotechnologies Texas, College Station, TX, United States
| | - Edward M. Dzialowski
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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3
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Davies KL, Smith DJ, El-Bacha T, Stewart ME, Easwaran A, Wooding PFP, Forhead AJ, Murray AJ, Fowden AL, Camm EJ. Development of cerebral mitochondrial respiratory function is impaired by thyroid hormone deficiency before birth in a region-specific manner. FASEB J 2021; 35:e21591. [PMID: 33891344 DOI: 10.1096/fj.202100075r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/13/2021] [Accepted: 03/26/2021] [Indexed: 12/20/2022]
Abstract
Thyroid hormones regulate adult metabolism partly through actions on mitochondrial oxidative phosphorylation (OXPHOS). They also affect neurological development of the brain, but their role in cerebral OXPHOS before birth remains largely unknown, despite the increase in cerebral energy demand during the neonatal period. Thus, this study examined prepartum development of cerebral OXPHOS in hypothyroid fetal sheep. Using respirometry, Complex I (CI), Complex II (CII), and combined CI&CII OXPHOS capacity were measured in the fetal cerebellum and cortex at 128 and 142 days of gestational age (dGA) after surgical thyroidectomy or sham operation at 105 dGA (term ~145 dGA). Mitochondrial electron transfer system (ETS) complexes, mRNA transcripts related to mitochondrial biogenesis and ATP production, and mitochondrial density were quantified using molecular techniques. Cerebral morphology was assessed by immunohistochemistry and stereology. In the cortex, hypothyroidism reduced CI-linked respiration and CI abundance at 128 dGA and 142 dGA, respectively, and caused upregulation of PGC1α (regulator of mitochondrial biogenesis) and thyroid hormone receptor β at 128 dGA and 142 dGA, respectively. In contrast, in the cerebellum, hypothyroidism reduced CI&II- and CII-linked respiration at 128 dGA, with no significant effect on the ETS complexes. In addition, cerebellar glucocorticoid hormone receptor and adenine nucleotide translocase (ANT1) were downregulated at 128 dGA and 142 dGA, respectively. These alterations in mitochondrial function were accompanied by reduced myelination. The findings demonstrate the importance of thyroid hormones in the prepartum maturation of cerebral mitochondria and have implications for the etiology and treatment of the neurodevelopmental abnormalities associated with human prematurity and congenital hypothyroidism.
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Affiliation(s)
- Katie L Davies
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Danielle J Smith
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Tatiana El-Bacha
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Max E Stewart
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Akshay Easwaran
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Peter F P Wooding
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Alison J Forhead
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.,Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Abigail L Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Emily J Camm
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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Tampakakis E, Mahmoud AI. The role of hormones and neurons in cardiomyocyte maturation. Semin Cell Dev Biol 2021; 118:136-143. [PMID: 33931308 DOI: 10.1016/j.semcdb.2021.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/19/2021] [Accepted: 03/29/2021] [Indexed: 12/28/2022]
Abstract
The heart undergoes profound morphological and functional changes as it continues to mature postnatally. However, this phase of cardiac development remains understudied. More recently, cardiac maturation research has attracted a lot of interest due to the need for more mature stem cell-derived cardiomyocytes for disease modeling, drug screening and heart regeneration. Additionally, neonatal heart injury models have been utilized to study heart regeneration, and factors regulating postnatal heart development have been associated with adult cardiac disease. Critical components of cardiac maturation are systemic and local biochemical cues. Specifically, cardiac innervation and the concentration of various metabolic hormones appear to increase perinatally and they have striking effects on cardiomyocytes. Here, we first report some of the key parameters of mature cardiomyocytes and then discuss the specific effects of neurons and hormonal cues on cardiomyocyte maturation. We focus primarily on the structural, electrophysiologic, metabolic, hypertrophic and hyperplastic effects of each factor. This review highlights the significance of underappreciated regulators of cardiac maturation and underscores the need for further research in this exciting field.
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Affiliation(s)
- Emmanouil Tampakakis
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA.
| | - Ahmed I Mahmoud
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA.
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Ulmer BM, Eschenhagen T. Human pluripotent stem cell-derived cardiomyocytes for studying energy metabolism. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118471. [PMID: 30954570 PMCID: PMC7042711 DOI: 10.1016/j.bbamcr.2019.04.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/26/2019] [Accepted: 04/01/2019] [Indexed: 12/25/2022]
Abstract
Cardiomyocyte energy metabolism is altered in heart failure, and primary defects of metabolic pathways can cause heart failure. Studying cardiac energetics in rodent models has principal shortcomings, raising the question to which extent human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) can provide an alternative. As metabolic maturation of CM occurs mostly after birth during developmental hypertrophy, the immaturity of hiPSC-CM is an important limitation. Here we shortly review the physiological drivers of metabolic maturation and concentrate on methods to mature hiPSC-CM with the goal to benchmark the metabolic state of hiPSC-CM against in vivo data and to see how far known abnormalities in inherited metabolic disorders can be modeled in hiPSC-CM. The current data indicate that hiPSC-CM, despite their immature, approximately mid-fetal state of energy metabolism, faithfully recapitulate some basic metabolic disease mechanisms. Efforts to improve their metabolic maturity are underway and shall improve the validity of this model.
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Affiliation(s)
- Bärbel M Ulmer
- University Medical Center Hamburg-Eppendorf, Institute of Experimental Pharmacology and Toxicology, 20246 Hamburg, Germany; German Centre for Heart Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
| | - Thomas Eschenhagen
- University Medical Center Hamburg-Eppendorf, Institute of Experimental Pharmacology and Toxicology, 20246 Hamburg, Germany; German Centre for Heart Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
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6
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Chattergoon NN. Thyroid hormone signaling and consequences for cardiac development. J Endocrinol 2019; 242:T145-T160. [PMID: 31117055 PMCID: PMC6613780 DOI: 10.1530/joe-18-0704] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/20/2019] [Indexed: 01/10/2023]
Abstract
The fetal heart undergoes its own growth and maturation stages all while supplying blood and nutrients to the growing fetus and its organs. Immature contractile cardiomyocytes proliferate to rapidly increase and establish cardiomyocyte endowment in the perinatal period. Maturational changes in cellular maturation, size and biochemical capabilities occur, and require, a changing hormonal environment as the fetus prepares itself for the transition to extrauterine life. Thyroid hormone has long been known to be important for neuronal development, but also for fetal size and survival. Fetal circulating 3,5,3'-triiodothyronine (T3) levels surge near term in mammals and are responsible for maturation of several organ systems, including the heart. Growth factors like insulin-like growth factor-1 stimulate proliferation of fetal cardiomyocytes, while thyroid hormone has been shown to inhibit proliferation and drive maturation of the cells. Several cell signaling pathways appear to be involved in this complicated and coordinated process. The aim of this review was to discuss the foundational studies of thyroid hormone physiology and the mechanisms responsible for its actions as we speculate on potential fetal programming effects for cardiovascular health.
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Affiliation(s)
- Natasha N Chattergoon
- Center for Developmental Health, Oregon Health and Science University, Portland, Oregon, USA
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, USA
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Krishnamurthy G. Cardiopulmonary Bypass in Premature and Low Birth Weight Neonates - Implications for Postoperative Care From a Neonatologist/Intensivist Perspective. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 2019; 22:2-9. [PMID: 31027559 DOI: 10.1053/j.pcsu.2019.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 02/26/2019] [Indexed: 11/11/2022]
Abstract
Prematurity and low weight remain significant risk factors for mortality after neonatal cardiac surgery despite steady gains in survival. Newer and lower weight thresholds for operability are constantly generated as surgeons gather proficiency, technical mastery, and experience in performing complex procedures on extremely small infants. Relationship between birth weight and survival after cardiac surgery is nonlinear with 2 kg being an inflection point below which marked decline in survival occurs. If strides toward improved survival in this weight category are to be made, understanding the inherent vulnerabilities of the premature and low birth weight infant is important in addition to acknowledging the vulnerabilities of the system in which care is delivered.
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Affiliation(s)
- Ganga Krishnamurthy
- Division of Neonatology, Columbia University Medical Center, New York, New York.
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8
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Gill AW. Postnatal cardiovascular adaptation. Arch Dis Child Fetal Neonatal Ed 2019; 104:F220-F224. [PMID: 30049726 DOI: 10.1136/archdischild-2017-314453] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/12/2022]
Abstract
The heart undergoes rapid transformations in function during the transition to extrauterine life. Our understanding of the adaptive physiology underlying this process is able to inform the clinical management of infants who are struggling to complete this complex transition. Much of our knowledge of the cardiac transition is derived from the preterm infant in whom the preparative adaptations are incomplete and clinical sequelae all too common. This review will re-examine the cardiac transition highlighting the physiology that drives it and suggest appropriate clinical intervention to support the process.
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Affiliation(s)
- Andrew William Gill
- Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia
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9
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Abstract
Children are at increased risk of perioperative respiratory and cardiovascular complications because of their unique respiratory and cardiovascular physiology compared to adults. Anaesthesia can exaggerate respiratory deterioration in young children because of their inability to control respiration and inherent susceptibility to rapid desaturation, airway obstruction, early respiratory fatigue and lung atelectasis. Premature infants (less than 60 weeks of postconceptional age) can be exposed to the danger of prolonged apnoea and consequent worsening of respiratory function. The transitional phase of circulation is vulnerable to revert to persistent foetal circulation in neonates. Myocardium and autonomic control of the heart is immature and different in neonates and infants compared to older children and adults and are predisposed to inadvertent life-threatening haemodynamic changes during the perioperative period. In this review article, we discuss respiratory and cardiovascular physiology in neonates, infants and younger children and their differences with older children and adults. We mainly focus on transitional physiology of both respiratory and cardiovascular system in newborns and infants and the deleterious changes that may occur during anaesthesia or perioperatively.
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Affiliation(s)
- Diganta Saikia
- Department of Anaesthesiology and Critical Care Medicine, Tezpur Medical College and Hospital, Tezpur, Sonitpur, Assam, India
| | - Bandana Mahanta
- Department of Anaesthesiology and Critical Care Medicine, Tezpur Medical College and Hospital, Tezpur, Sonitpur, Assam, India
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Sofronova SI, Gaynullina DK, Shvetsova AA, Borzykh AA, Selivanova EK, Kostyunina DS, Sharova AP, Martyanov AA, Tarasova OS. Antenatal/early postnatal hypothyroidism alters arterial tone regulation in 2-week-old rats. J Endocrinol 2017; 235:137-151. [PMID: 28794003 DOI: 10.1530/joe-17-0225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 08/09/2017] [Indexed: 01/05/2023]
Abstract
The mechanisms of vascular alterations resulting from early thyroid hormones deficiency are poorly understood. We tested the hypothesis that antenatal/early postnatal hypothyroidism would alter the activity of endothelial NO pathway and Rho-kinase pathway, which are specific for developing vasculature. Dams were treated with propylthiouracil (PTU, 7 ppm) in drinking water during gestation and 2 weeks after delivery, and their progeny had normal body weight but markedly reduced blood levels of thyroid hormones (ELISA). Small arteries from 2-week-old male pups were studied using wire myography, qPCR and Western blotting. Mesenteric arteries of PTU pups, compared to controls, demonstrated smaller maximum response to α1-adrenergic agonist methoxamine and reduced mRNA contents of smooth muscle differentiation markers α-actin and SERCA2A. Inhibition of basal NO synthesis by l-NNA led to tonic contraction of mesenteric arteries and augmented their contractile responses to methoxamine; both l-NNA effects were impaired in PTU pups. PTU pups demonstrated lower blood level of NO metabolites compared to control group (Griess reaction). Rho-kinase inhibitor Y27632 strongly reduced mesenteric arteries responses to methoxamine in PTU pups, that was accompanied by elevated Rho-kinase content in their arteries in comparison to control ones. Unlike mesenteric, saphenous arteries of PTU pups, compared to controls, had no changes in α-actin and SERCA2A contents and in responses to l-NNA and Y27632. In conclusion, thyroid hormones deficiency suppresses the anticontractile effect of NO and potentiates the procontractile Rho-kinase effects in mesenteric arteries of 2-week-old pups. Such alterations disturb perinatal cardiovascular homeostasis and might lead to cardiovascular pathologies in adulthood.
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Affiliation(s)
- Svetlana I Sofronova
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
| | - Dina K Gaynullina
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
- Department of PhysiologyRussian National Research Medical University, Moscow, Russia
| | - Anastasia A Shvetsova
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
| | - Anna A Borzykh
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
| | - Ekaterina K Selivanova
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
| | - Daria S Kostyunina
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
| | - Anna P Sharova
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
| | - Andrey A Martyanov
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
| | - Olga S Tarasova
- Institute for Biomedical ProblemsRussian Academy of Sciences, Moscow, Russia
- Faculty of BiologyM.V. Lomonosov Moscow State University, Moscow, Russia
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11
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Abstract
The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are essential for normal growth and development of the fetus. Their bioavailability in utero depends on development of the fetal hypothalamic-pituitary-thyroid gland axis and the abundance of thyroid hormone transporters and deiodinases that influence tissue levels of bioactive hormone. Fetal T4 and T3 concentrations are also affected by gestational age, nutritional and endocrine conditions in utero, and placental permeability to maternal thyroid hormones, which varies among species with placental morphology. Thyroid hormones are required for the general accretion of fetal mass and to trigger discrete developmental events in the fetal brain and somatic tissues from early in gestation. They also promote terminal differentiation of fetal tissues closer to term and are important in mediating the prepartum maturational effects of the glucocorticoids that ensure neonatal viability. Thyroid hormones act directly through anabolic effects on fetal metabolism and the stimulation of fetal oxygen consumption. They also act indirectly by controlling the bioavailability and effectiveness of other hormones and growth factors that influence fetal development such as the catecholamines and insulin-like growth factors (IGFs). By regulating tissue accretion and differentiation near term, fetal thyroid hormones ensure activation of physiological processes essential for survival at birth such as pulmonary gas exchange, thermogenesis, hepatic glucogenesis, and cardiac adaptations. This review examines the developmental control of fetal T4 and T3 bioavailability and discusses the role of these hormones in fetal growth and development with particular emphasis on maturation of somatic tissues critical for survival immediately at birth.
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Affiliation(s)
- A J Forhead
- Department of PhysiologyDevelopment and Neuroscience, University of Cambridge, Physiology Building, Downing Street, Cambridge CB2 3EG, UKDepartment of Biological and Medical SciencesOxford Brookes University, Oxford OX3 0BP, UKDepartment of PhysiologyDevelopment and Neuroscience, University of Cambridge, Physiology Building, Downing Street, Cambridge CB2 3EG, UKDepartment of Biological and Medical SciencesOxford Brookes University, Oxford OX3 0BP, UK
| | - A L Fowden
- Department of PhysiologyDevelopment and Neuroscience, University of Cambridge, Physiology Building, Downing Street, Cambridge CB2 3EG, UKDepartment of Biological and Medical SciencesOxford Brookes University, Oxford OX3 0BP, UK
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12
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Yang X, Rodriguez M, Pabon L, Fischer KA, Reinecke H, Regnier M, Sniadecki NJ, Ruohola-Baker H, Murry CE. Tri-iodo-l-thyronine promotes the maturation of human cardiomyocytes-derived from induced pluripotent stem cells. J Mol Cell Cardiol 2014; 72:296-304. [PMID: 24735830 DOI: 10.1016/j.yjmcc.2014.04.005] [Citation(s) in RCA: 307] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 03/15/2014] [Accepted: 04/05/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) have great potential as a cell source for therapeutic applications such as regenerative medicine, disease modeling, drug screening, and toxicity testing. This potential is limited, however, by the immature state of the cardiomyocytes acquired using current protocols. Tri-iodo-l-thyronine (T3) is a growth hormone that is essential for optimal heart growth. In this study, we investigated the effect of T3 on hiPSC-CM maturation. METHODS AND RESULTS A one-week treatment with T3 increased cardiomyocyte size, anisotropy, and sarcomere length. T3 treatment was associated with reduced cell cycle activity, manifest as reduced DNA synthesis and increased expression of the cyclin-dependent kinase inhibitor p21. Contractile force analyses were performed on individual cardiomyocytes using arrays of microposts, revealing an almost two-fold higher force per-beat after T3 treatment and also an enhancement in contractile kinetics. This improvement in force generation was accompanied by an increase in rates of calcium release and reuptake, along with a significant increase in sarcoendoplasmic reticulum ATPase expression. Finally, although mitochondrial genomes were not numerically increased, extracellular flux analysis showed a significant increase in maximal mitochondrial respiratory capacity and respiratory reserve capability after T3 treatment. CONCLUSIONS Using a broad spectrum of morphological, molecular, and functional parameters, we conclude that T3 is a driver for hiPSC-CM maturation. T3 treatment may enhance the utility of hiPSC-CMs for therapy, disease modeling, or drug/toxicity screens.
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Affiliation(s)
- Xiulan Yang
- Department of Pathology, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Marita Rodriguez
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98109, USA
| | - Lil Pabon
- Department of Pathology, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Karin A Fischer
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Hans Reinecke
- Department of Pathology, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Nathan J Sniadecki
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98109, USA; Department of Bioengineering, University of Washington, Seattle, WA 98109, USA
| | | | - Charles E Murry
- Department of Pathology, University of Washington, Seattle, WA 98109, USA; Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.
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13
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Tomat AL, Juriol LV, Gobetto MN, Veiras LC, Mendes Garrido Abregú F, Zilberman J, Fasoli H, Elesgaray R, Costa MÁ, Arranz CT. Morphological and functional effects on cardiac tissue induced by moderate zinc deficiency during prenatal and postnatal life in male and female rats. Am J Physiol Heart Circ Physiol 2013; 305:H1574-83. [DOI: 10.1152/ajpheart.00578.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The aim of this study was to evaluate whether moderate zinc restriction in rats throughout fetal life, lactation, and/or postweaning growth results in early changes in cardiac morphology predisposing the onset of cardiac dysfunction in adult life as well as sex-related differences in the adaptation to this nutritional injury. Female Wistar rats received low or control zinc diets from the beginning of pregnancy up to offspring weaning. After being weaned, offspring were fed either a low or control zinc diet until 81 days. Systolic blood pressure was measured. Echocardiographic and electrocardiographic examinations, morphological experiments, and apoptosis by TUNEL assay were performed in the left ventricle. In the early stages, zinc-deficient male and female offspring showed an increase in cardiomyocyte diameter, probably associated with an increase in cardiac apoptotic cells, but smaller myocyte diameters in adulthood. In adult males, this nutritional injury induced decreased contractility and dilatation of the left ventricle, not allowing the heart to compensate the higher levels of blood pressure, and hypertrophic remodeling of coronary arteries associated with increased blood pressure. Adequate zinc intake during postweaning life did not overcome blood pressure levels but reversed some of the detrimental effects of earlier zinc deficiency in cardiac morphology and function. Females were less sensitive to this deficiency, exhibiting normal levels of blood pressure and no structural or functional heart alterations in adult life. The present study demonstrates that the effects of zinc deficiency on blood pressure, cardiac morphology, and function differ between sexes, with males more predisposed to develop cardiovascular diseases in adulthood.
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Affiliation(s)
- Analia Lorena Tomat
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - Lorena Vanesa Juriol
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - María Natalia Gobetto
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - Luciana Cecilia Veiras
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - Facundo Mendes Garrido Abregú
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - Judith Zilberman
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - Héctor Fasoli
- Laboratorio de Química y Ciencia Ambiental, Facultad de Ciencias Fisicomatemáticas e Ingeniería, Universidad Católica Argentina, Buenos Aires, Argentina
| | - Rosana Elesgaray
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - María Ángeles Costa
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
| | - Cristina Teresa Arranz
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco-Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires, Argentina; and
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Krishnamurthy G, Ratner V, Bacha E. Neonatal cardiac care, a perspective. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 2013; 16:21-31. [PMID: 23561814 DOI: 10.1053/j.pcsu.2013.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Every year in the United States approximately 40,000 infants are born with congenital heart disease. Several of these infants require corrective or palliative surgery in the neonatal period. Mortality rates after cardiac surgery are highest amongst neonates, particularly those born prematurely. There are several reasons for the increased surgical mortality risk in neonates. This review outlines these risks, with particular emphasis on the relative immaturity of the organ systems in the term and preterm neonate.
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Affiliation(s)
- Ganga Krishnamurthy
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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15
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16
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Hillman N, Kallapur SG, Jobe A. Physiology of transition from intrauterine to extrauterine life. Clin Perinatol 2012; 39:769-83. [PMID: 23164177 PMCID: PMC3504352 DOI: 10.1016/j.clp.2012.09.009] [Citation(s) in RCA: 232] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The transition from fetus to newborn is the most complex adaptation that occurs in human experience. Lung adaptation requires coordinated clearance of fetal lung fluid, surfactant secretion, and onset of consistent breathing. The cardiovascular response requires striking changes in blood flow, pressures, and pulmonary vasodilation. Energy metabolism and thermoregulation must be quickly controlled. The primary mediators that prepare the fetus for birth and support the multiorgan transition are cortisol and catecholamine. Abnormalities in adaptation are frequently found following preterm birth or cesarean delivery at term, and many of these infants need delivery room resuscitation to assist in this transition.
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17
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Chattergoon NN, Giraud GD, Louey S, Stork P, Fowden AL, Thornburg KL. Thyroid hormone drives fetal cardiomyocyte maturation. FASEB J 2011; 26:397-408. [PMID: 21974928 DOI: 10.1096/fj.10-179895] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tri-iodo-l-thyronine (T(3)) suppresses the proliferation of near-term serum-stimulated fetal ovine cardiomyocytes in vitro. Thus, we hypothesized that T(3) is a major stimulant of cardiomyocyte maturation in vivo. We studied 3 groups of sheep fetuses on gestational days 125-130 (term ∼145 d): a T(3)-infusion group, to mimic fetal term levels (plasma T(3) levels increased from ∼0.1 to ∼1.0 ng/ml; t(1/2)∼24 h); a thyroidectomized group, to produce low thyroid hormone levels; and a vehicle-infusion group, to serve as intact controls. At 130 d of gestation, sections of left ventricular freewall were harvested, and the remaining myocardium was enzymatically dissociated. Proteins involved in cell cycle regulation (p21, cyclin D1), proliferation (ERK), and hypertrophy (mTOR) were measured in left ventricular tissue. Evidence that elevated T(3) augmented the maturation rate of cardiomyocytes included 14% increased width, 31% increase in binucleation, 39% reduction in proliferation, 150% reduction in cyclin D1 protein, and 500% increase in p21 protein. Increased expression of phospho-mTOR, ANP, and SERCA2a also suggests that T(3) promotes maturation and hypertrophy of fetal cardiomyocytes. Thyroidectomized fetuses had reduced cell cycle activity and binucleation. These findings support the hypothesis that T(3) is a prime driver of prenatal cardiomyocyte maturation.
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18
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Cardiac PPARalpha Protein Expression is Constant as Alternate Nuclear Receptors and PGC-1 Coordinately Increase During the Postnatal Metabolic Transition. PPAR Res 2011; 2008:279531. [PMID: 18288283 PMCID: PMC2233871 DOI: 10.1155/2008/279531] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 07/22/2007] [Indexed: 12/25/2022] Open
Abstract
Gene expression data obtained in mouse heart indicate that increased expression for the nuclear receptor, peroxisomal proliferator activated receptor alpha (PPARalpha), prompts the postnatal transition from predominantly carbohydrate to fatty acid oxidation preference. However, no phenotypic or proteomic data are available to confirm downstream signaling and metabolic transition in mice. We studied the hypothesis that shifts in nuclear receptor expression trigger the newborn metabolic switch in a newborn sheep. This species is well characterized with regards to developmental changes in substrate oxidative metabolism. Heart tissues from fetal (130 days gestation), newborn </=24 hours, and 30-day old lambs were evaluated for protein expression from multiple enzymes controlling oxidative metabolism as well as principal nuclear receptors and coactivators. Although muscle and liver type carnitine palmitoyl transferases I showed no significant changes to correspond to the metabolic transition, hexokinase II protein content showed a profound transient drop, and pyruvate dehydrogenase kinase steadily increased. PPARalpha showed no increases preceding or during the transition, while peroxisomal proliferator activated receptor gamma coactivator-1 (PGC-1) increased approximately 20-fold transiently in newborn heart in conjunction with significant increases in thyroid hormone receptor alpha1 and retinoid-activated receptor alpha. These data challenge the paradigm that increases in PPARalpha prompt the postnatal metabolic switch, and suggest that other nuclear receptors play a major role. As thyroid hormone (TH) modulates PGC-1 expression in sheep during development, these data further suggest that well-characterized perinatal TH surge in sheep contributes to this metabolic switch.
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Bal MP, de Vries WB, Steendijk P, Homoet-van der Kraak P, van der Leij FR, Baan J, van Oosterhout MFM, van Bel F. Histopathological changes of the heart after neonatal dexamethasone treatment: studies in 4-, 8-, and 50-week-old rats. Pediatr Res 2009; 66:74-9. [PMID: 19287345 DOI: 10.1203/pdr.0b013e3181a283a0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Dexamethasone (Dex), for prevention of chronic lung disease in preterm infants, showed potential negative long-term effects. Studies regarding long-term cardiovascular effects are lacking. We investigated possible histopathological myocardial changes after neonatal Dex in the young and adult rat heart. Rats were treated with Dex on d 1, 2, and 3 (0.5, 0.3, and 0.1 mg/kg) of life. Control-pups received saline. At 4, 8, and 50 wk after birth rats were killed and anatomic data collected. Heart tissue was stained with hematoxylin and eosin, Cadherin-periodic acid schiff, and sirius red for cardiomyocyte morphometry and collagen determination. Presence of macrophages and mast cells was analyzed. Cardiomyocyte length of the Dex-treated rats was increased in all three age groups, whereas ventricular weight was reduced. Cardiomyocyte volumes were increased at 50 wk indicating cellular hypertrophy. Collagen content gradually increased with age and was 62% higher in Dex rats at 50 wk. Macrophage focus score and mast cell count were also higher. Neonatal Dex affects normal heart growth resulting in cellular hypertrophy and increased collagen deposition in the adult rat heart. Because previous studies in rats showed premature death, suggesting cardiac failure, cardiovascular follow-up of preterm infants treated with glucocorticoids should be considered.
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Affiliation(s)
- Miriam P Bal
- Department of Neonatology, University Medical Center Utrecht, Utrecht, The Netherlands
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20
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Abstract
Thyroid hormone plays an important role in regulating cardiovascular function during the transition to extrauterine physiology. Multiple mechanisms participate, ranging from transcriptional to more immediate nongenomic modes of regulation.
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de Vries WB, Bal MP, Homoet-van der Kraak P, Kamphuis PJGH, van der Leij FR, Baan J, Steendijk P, de Weger RA, van Bel F, van Oosterhout MFM. Suppression of physiological cardiomyocyte proliferation in the rat pup after neonatal glucocorticosteroid treatment. Basic Res Cardiol 2005; 101:36-42. [PMID: 16283594 DOI: 10.1007/s00395-005-0557-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 09/01/2005] [Accepted: 09/21/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Glucocorticosteroids (mostly dexamethasone) are widely used to prevent chronic lung disease in premature infants. Neonatal rats treated with dexamethasone have been shown to have reduced cardiac mass and cardiomyocyte hypertrophy, suggesting a lower number of cardiomyocytes at adult age, and a severely reduced life expectancy. In the present study we tested the hypothesis that a lower number of cardiomyocytes in later life is caused by a reduced cardiomyocyte proliferation and/or by early cell death (apoptosis). METHODS AND RESULTS Rat pups received dexamethasone or saline control on day 1, 2 and 3 and were sacrificed at day 0, 2, 4, 7 and 21. The cardiomyocytes of dexamethasone treated pups showed a reduced proliferation as indicated by a lower mitotic index and reduced number of Ki-67 positive cardiomyocytes on day 2 and 4 as compared to day 0 and day 7 and also as compared to the age-matched saline pups. On day 7 and day 21 the mitotic index was not different between groups. From day 2 onward up to day 21 dexamethasone treated pups showed a lower number of cardiomyocytes. The cardiomyocytes showed no signs (<<1%) of apoptosis (Caspase-3 and cleaved-PARP) in any group. CONCLUSION The temporary suppression of cardiomyocyte hyperplasia found in dexamethasone treated pups eventually leads to a reduced number and hypertrophy of cardiomyocytes during adult life.
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Affiliation(s)
- Willem B de Vries
- Department of Neonatology, University Medical Center Utrecht, Wilhelmina Children's Hospital Roomnr. KE.04.123.1, 85090, 3508 AB, Utrecht, The Netherlands
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22
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Tan T, Mizobe N, Sugiyama H, Maeda Y, Naitou A, Kodera K, Sato T, Nakazawa S. Supplemental nitrogen inhalation therapy in very low-birth-weight infants with patent ductus arteriosus. Pediatr Cardiol 2005; 26:801-4. [PMID: 16132276 DOI: 10.1007/s00246-005-0947-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Very low-birth weight infants with patent ductus arteriosus (PDA) accompanied by severe heart failure do not respond to indomethacine therapy. It is essential to stabilize the general condition of these infants until surgical intervention. We tried to regulate the pulmonary blood flow to control congestive heart failure by administering supplemental nitrogen inhalation therapy to six very low-birth-weight infants with PDA. After the inhalation of supplemental nitrogen gas was begun, the arterial oxygen saturation and partial oxygen pressure immediately decreased. Furthermore, the blood pH, systolic pressure, and urine output significantly increased. The infants were well stabilized. Furthermore, there were no complications related to nitrogen gas inhalation. Supplemental nitrogen inhalation therapy is an effective and feasible therapy for severe congestive heart failure in very low-birth-weight infants with PDA.
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Affiliation(s)
- T Tan
- Division of Neonatology, Perinatal Center, Yamanashi Prefectural Central Hospital, Yamanashi, 409-3898, Japan.
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Chen K, Carey LC, Valego NK, Liu J, Rose JC. Thyroid hormone modulates renin and ANG II receptor expression in fetal sheep. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1006-14. [PMID: 15919736 DOI: 10.1152/ajpregu.00046.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal renin-angiotensin system (RAS) activity is developmentally regulated, increasing in late gestation toward term. At the same time, fetal hemodynamic parameters change, with blood pressure increasing and heart rate decreasing. During this period, fetal plasma thyroid hormone concentrations also increase significantly. In this study we utilized the technique of thyroidectomy (TX), which removes thyroid hormone from the circulation, to investigate the importance of thyroid hormone on the developmental changes in the RAS (in plasma, kidney, heart, and lung) and hemodynamic regulation in fetal sheep. TX was performed at 120 days of gestational age (dGA), and control fetuses were sham operated. Immediately before necropsy (∼137 dGA), fetuses were infused with isoproterenol and the hemodynamic responses were noted. TX significantly decreased plasma thyroid hormone concentrations and renal renin mRNA and renal active renin levels but did not change fetal plasma active renin levels. TX decreased both angiotensin II receptor subtype 1 (AT1) mRNA and protein levels in kidney and lung but not in the left ventricle. TX also was associated with increased ANG II receptor subtype 2 (AT2) mRNA and protein at the 44-kDa band in kidney, whereas AT2 protein was decreased at the 78-kDa level in kidney and lung tissue only. TX fetuses had significantly lower basal mean arterial blood pressures (MAP) and heart rates than controls. Isoproterenol infusion decreased MAP in TX fetuses. These findings support the hypothesis that thyroid hormone is important in modulating maturation of RAS and cardiovascular function in the late-gestation fetal sheep.
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Affiliation(s)
- Kai Chen
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1066, USA
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McClure TD, Young ME, Taegtmeyer H, Ning XH, Buroker NE, López-Guisa J, Portman MA. Thyroid hormone interacts with PPARalpha and PGC-1 during mitochondrial maturation in sheep heart. Am J Physiol Heart Circ Physiol 2005; 289:H2258-64. [PMID: 16024569 DOI: 10.1152/ajpheart.00473.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thyroid hormone (TH) promotes cardiac mitochondrial maturation and substrate metabolism after birth. This regulation involves ligand-dependent binding of nuclear TH receptors to target gene elements. TH also putatively controls genes indirectly by modulating transcription and/or translation of other nuclear steroid receptors and coactivators, such as peroxisome proliferator-activated receptor-alpha (PPARalpha) and peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1). We tested the hypothesis that TH influences PPARalpha and PGC-1 regulation of metabolic genes during postnatal maturation in sheep heart in vivo. We measured their mRNAs and/or protein levels and downstream targets in left ventricle from lambs: fetal (F), 30-day-old after postnatal thyroidectomy (THY), and 30-day-old euthyroid (Con). Both PPARalpha and PGC-1 mRNA expression decreased from F to Con, while PGC-1 protein increased substantially and PPARalpha did not change. THY limited this mRNA response and attenuated the paradoxical postnatal PGC-1 protein elevation but did not alter mRNA levels for PPARalpha, nuclear respiratory factor-1 and hypoxia-inducible factor-1alpha. THY promotion in PPARalpha mRNA did not change PPARalpha protein or mRNA for PPARalpha target genes, pyruvate-dehydrogenase kinase 4 (PDK4) and muscle type carnitine palmitoyltransferase I (mCPTI). THY reduction in PGC-1 protein occurred, while reducing cytochrome c oxidase and cytochrome c content and decreasing cardiac maximal inherent respiratory capacity. These data imply that TH modulates mitochondrial maturation partly through posttranscriptional control of PGC-1, while any important regulation of PDK4 and mCPTI by change in PPARalpha protein expression remains doubtful. Also, the paradoxical expression pattern between mRNA and protein, particularly for PGC-1, suggests a feedback control mechanism.
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Affiliation(s)
- Timothy D McClure
- University of Washington, School of Medicine, and Children's Hospital and Regional Medical Center W4841, 4800 Sand Point Way NE, Seattle, WA 98105, USA
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Firat A, Ozpinar A, Serpek B, Haliloğlu S. Comparisons of Serum Somatotropin, 3,5,3′-Triiodothyronine, Thyroxine, Total Protein and Free Fatty Acid Levels in Newborn Sakiz Lambs Separated from or Suckling Their Dams. ANNALS OF NUTRITION AND METABOLISM 2005; 49:88-94. [PMID: 15802903 DOI: 10.1159/000084741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Accepted: 10/08/2004] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To determine the effects on serum somatotropin, 3,5,3'-triiodothyronine (T(3)), thyroxine (T(4)), free fatty acids (FFAs) and total protein levels of different feedings and age in Sakiz sheep that have a high twin-bearing rate supported by estrous synchronization. METHODS 20 newborn lambs were used in the study. Lambs were divided into 2 equal groups. The lambs in 1 group were separated from their dams following parturition, and those in other group were kept together with their dams. Separated lambs were fed commercial cow's milk for 2.5 weeks. After that, they were fed a milk substitute, hay and concentrated supplement for 2 months, and from the end of the 2 months they were fed hay and concentrated supplement. The lambs in other group were kept together with their dams only during the day and in addition were fed hay and concentrated supplement. After 2 months, they were maintained feeding only on hay and concentrated supplement. Blood samples were taken from vena jugularis of lambs at 12 and 24-48 h, and 14, 28, 42 and 56-90 days after parturition. Serum samples were analyzed for somatotropin by enzyme immunoassay, for T(3) and T(4) by radioimmunoassay, and for total protein and FFA by a spectrophotometric method. RESULTS Serum somatotropin levels were insignificantly different between the lambs with and without their dams. Serum T(3) levels were generally lower in the separated lambs than those in other group. Serum T(4) levels were significantly lower in the separated lambs 48 h and 90 days after parturition than those in other group. Serum FFAs were insignificantly different between 2 groups. Serum total protein concentrations were lower in the separated lambs than lambs kept together with their dams (significantly at 12 and 48 h and 14 days). CONCLUSION Ingestion of colostrum and dam milk markedly affected serum total protein levels, but body weight and serum somatotropin levels were insignificantly affected. Also serum T(3) and T(4) levels markedly decreased with advancing age. Serum FFA levels were not affected by the trial.
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Affiliation(s)
- Ayşen Firat
- Department of Biochemistry, Faculty of Veterinary Medicine, Istanbul University, Avcilar, Istanbul, Turkey.
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Portman MA, Qian K, Krueger J, Ning XH. Direct action of T3 on phosphorylation potential in the sheep heart in vivo. Am J Physiol Heart Circ Physiol 2005; 288:H2484-90. [PMID: 15637117 DOI: 10.1152/ajpheart.00848.2004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thyroid acting through ligand binding to nuclear receptors modifies myocardial respiratory kinetics and oxidative phosphorylation in the heart. Direct nongenomic action of thyroid hormone on high-energy phosphate concentrations and respiratory kinetics has never been proven in vivo but might be responsible for observed changes in oxygen utilization efficiency immediately after triiodothyronine (T3) administration. We tested the hypothesis that T3 directly and rapidly modifies myocardial high-energy phosphate concentrations and phosphorylation potential in vivo. Anesthetized sheep (age 28-40 days) thyroidectomized shortly after birth (Thy) and euthyroid age-matched controls (Con) underwent median sternotomy and received T3 infusion (0.8 microg/kg), followed by epinephrine infusion to increase myocardial oxygen consumption (MVo2). 31P magnetic resonance spectra were monitored via a surface coil over the left ventricle. T3 increased phosphocreatine (PCr)/ATP and decreased ADP in Thy animals without causing a change in MVo2. T3 produced no changes in high-energy phosphates in Con animals. T3 did not modify the PCr/ATP or ADP response to epinephrine and elevation in MVo2 in either group. Cardiac mitochondria isolated from Thy and Con animals showed no change in respiratory rate or ADP/ATP exchange efficiency after T3 incubation. T3 infusion in a hypothyroid state decreases ADP concentration, thereby altering the equilibrium between phosphorylation potential and myocardial respiratory rate. These T3-induced effects are not due to changes in ADP/ATP exchange efficiency through action at the adenine nucleotide translocator but may be due to T3 mediation of substrate utilization, confirmed in other models.
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Affiliation(s)
- Michael A Portman
- Division of Cardiology, Department of Pediatrics, University of Washington School of Medicine, Seattle, Wahington 98105, USA.
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27
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Abstract
Dr Abraham Rudolph is one of the most distinguished pediatric cardiologists in the world. He entered pediatric cardiology (almost by accident) when the subject was still in its infancy and was present at--and indeed contributed to--most of its advances. He is best known for his studies on the pathophysiology of congenital heart diseases and for imaginative studies of fetal cardiovascular development and the transition to postnatal life.
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Affiliation(s)
- Julien I E Hoffman
- Department of Pediatrics (Emeritus) and Cardiovascular Research Institute, University of California, San Francisco, California 94143, USA.
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28
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Thuett KA, Roots EH, Mitchell LP, Gentles BA, Anderson TA, Smith EE. In utero and lactational exposure to ammonium perchlorate in drinking water: effects on developing deer mice at postnatal day 21. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2002; 65:1061-1076. [PMID: 12167219 DOI: 10.1080/152873902760125228] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of in utero and lactational exposure to ammonium perchlorate (AP), a component of rocket fuel and a thyroid toxicant, on developing deer mice (Peromyscus maniculatus) were evaluated. Breeding pairs were dosed continuously with 0, 1 nM, 1 micro M, or 1 mM AP in drinking water, from cohabitation until pups were euthanized at postnatal day (PND) 21. Pups from the second litter were used for evaluation in this study. No significant differences were observed in any analysis performed when litter means were used in statistical analysis. All reported significant differences occurred when statistical analysis was performed on individual pup data. Body weights were significantly different between treatments at PND 5 and PND 20, with the 1- micro M body weights being lower than that of controls. Body weight and liver weight in the 1-mM group were significantly higher than the 1- micro M weights at PND 21 when analyzed by analysis of variance (ANOVA). However, there were no significant differences in liver weights when analyzed with body weight as the covariate. Heart weights were significantly different between males and females. Male heart weights in the 1- microM and 1-mM groups were significantly lower than in controls when analyzed by analysis of covariance (ANCOVA) with body weight as the covariate. Litter size and survival percentage were not significantly different among treatments. Although significant differences were observed only when the individual pup was used as the experimental unit, these data suggest that AP exposure at different concentrations may variably alter body weight and male heart weight during mammalian development.
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Affiliation(s)
- Kerry A Thuett
- Texas Tech University, Institute of Environmental and Human Health, Lubbock, Texas 79409, USA
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29
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Silverman NH, Silverman H. Abraham Morris Rudolph. Cardiol Young 2002; 12:393-400. [PMID: 12206565 DOI: 10.1017/s1047951100013020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Székely M, Pétervári E, Andrews J. Thermal and nutritional status and the development of postnatal rise in minimum metabolic rate of the rabbit. J Therm Biol 2001. [DOI: 10.1016/s0306-4565(01)00061-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Asami T, Suzuki H, Yazaki S, Sato S, Uchiyama M. Effects of thyroid hormone deficiency on electrocardiogram findings of congenitally hypothyroid neonates. Thyroid 2001; 11:765-8. [PMID: 11525269 DOI: 10.1089/10507250152484600] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hypothyroid status is believed to cause various metabolic changes in infants. However, it is interesting that even severely hypothyroid neonates, detected during mass neonatal screening, rarely show bradycardia, hypothermia, or inactivity. To study cardiac functions of screen-detected neonates with congenital hypothyroidism (CH), we recorded the electrocardiograms (ECG) of 53 screen-detected CH neonates before levothyroxine (LT4) replacement therapy, and 15 age-matched normal neonates for controls. The 53 CH neonates were divided into two groups according to initial serum thyroid hormone levels: a mildly hypothyroid group (n = 37), serum thyroid-stimulating hormone (TSH) less than 100 microIU/mL and free thyroxine (FT4) 0.6 ng/dl or more; and a severely hypothyroid group (n = 16), TSH 100 microIU/mL or more and FT4 less than 0.6 ng/dL. TSH, FT4, and other blood chemicals were measured on an autoanalyzer (Hitachi 7170). After blood sampling, the ECG was recorded during induced sleep by oral administration of triclofos sodium syrup. ECG parameters, including HR, PR, QRS, QT time and corrected QT time (QTc) were automatically obtained, using an auto-ECG analyzing system. The following results were obtained. No CH patients showed abnormal ECG findings. There was no significant difference of the mean heart rates (HRs) between the mildly hypothyroid (147.5 +/- 16.3 beats per minute) and the control group (148.3 +/- 12.1 beats per minute). The mean HR in the severely hypothyroid group (134.0 +/- 17.9 beats per minute, p = 0.007) was significantly low compared with the normal control group. However, all values were within normal ranges. QTc in the severely hypothyroid group (0.414 +/- 0.015, p = 0.033) was significantly shorter than in the control group (0.440 +/- 0.052). No statistical differences of PR, QRS, and QT time were noted among the three groups. All ECG parameters were within normal ranges. HR positively correlated with FT4 and log (FT4), and negatively with TSH and log (TSH). From these results we conclude that the deficiency of thyroid hormones does not affect ECG findings of congenitally hypothyroid neonates. This may be consistent with the unexpectedly mild signs and symptoms of screen-detected hypothyroid neonates.
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Affiliation(s)
- T Asami
- Department of Pediatrics, School of Medicine, Niigata University, Japan.
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Senzaki H, Naito C, Kobayashi T, Sasaki N, Kyo S, Yokote Y, Ishizawa A. Influence of age (body size) on the Fontan circulation--analysis by a theoretical model. JAPANESE CIRCULATION JOURNAL 2000; 64:943-8. [PMID: 11194288 DOI: 10.1253/jcj.64.943] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Among the original selection criteria for the Fontan operation, the recommended age at the time of surgery has been 4 years or older, but recent clinical data have indicated the feasibility of this procedure in younger patients. Because age may influence the properties of the systemic vascular bed, changes in systemic vascular resistance (Rs) and systemic vascular compliance (Cs) associated with physical development were quantified in 86 pediatric patients without known abnormalities of the systemic circulation, and the effects of age (body size) on Fontan circulation were then analyzed using an analytical model of the cardiovascular system. As the body surface area (BSA) of the patient decreased, Cs also decreased significantly (r=0.81, p<0.001). Based upon this relationship between BSA and Cs, the analytical model showed that the impedance (ventricular afterload) of the Fontan circulation significantly increased as Cs decreased with the decrease in BSA. Moreover, the increase in impedance in response to changes in heart rate or Rs was inversely proportional to the BSA. However, these findings were significant only when the BSA was below 0.3 m2. Small BSA, or a lower age, has minimal effects on the Fontan circulation until it comes close to the infant value, and thus the Fontan procedure may be feasible much earlier than formerly recommended when the hemodynamics are otherwise acceptable.
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Affiliation(s)
- H Senzaki
- Department of Pediatrics and Pediatric Cardiology, Saitama Heart Institutes, Saitama Medical School Hospital, Iruma-Gun, Japan.
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Portman MA, Xiao Y, Qian K, Tucker RL, Parish SM, Ning XH. Thyroid hormone coordinates respiratory control maturation and adenine nucleotide translocator expression in heart in vivo. Circulation 2000; 102:1323-9. [PMID: 10982550 DOI: 10.1161/01.cir.102.11.1323] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The signal transduction mechanism linking mitochondrial ATP synthesis with cytosolic ATP utilization in heart changes during postnatal development in vivo. This maturational process occurs in parallel with accumulation of mitochondrial adenine nucleotide translocator (ANT), which provides a possible site for respiratory control. We postulated that thyroid hormone regulates these maturational processes. METHODS AND RESULTS We used (31)P MR spectroscopy to determine the relationship between myocardial high-energy phosphates, phosphocreatine, and ADP and oxygen consumption (MVO(2)) during epinephrine stimulation in 32- to 40-day-old lambs thyroidectomized after birth (THY) and age-matched controls. Steady-state protein and mRNA levels for ANT isoforms and beta-F(1)-ATPase were assessed from left ventricular tissues by Western and Northern blotting. With greater doses of epinephrine, THY attained lower peak MVO(2) than controls (P:<0.05). Controls maintained high-energy phosphate levels, unlike THY, which demonstrated significantly decreased phosphocreatine/ATP and increased cytosolic ADP despite lower peak MVO(2). No significant differences in beta-F(1)-ATPase protein or mRNA occurred between groups. However, ANT isoform mRNA levels were 2-fold greater and protein levels 4-fold greater in control hearts. CONCLUSIONS These data imply that the maturational shift away from ADP-mediated respiratory control is regulated by thyroid hormone in vivo. Specific thyroid-modulated increases in ANT mRNA and protein imply that this regulation occurs in part at a pretranslational level.
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Affiliation(s)
- M A Portman
- Division of Cardiology, Department of Pediatrics, University of Washington School of Medicine, and Children's Hospital and Regional Medical Center, Seattle, WA 98105-0371, USA.
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Abstract
Myocardial growth during fetal life is accomplished by proliferation of the number of myocytes (hyperplasia). Shortly after birth, normal growth of the heart is predominantly due to increase in cell size (hypertrophy), and myocytes largely lose the capability to replicate. This change is characterized by a decrease in myocardial DNA concentration and an increase in protein/DNA concentration ratio. Among many of the events associated with birth is an increase in plasma cortisol concentrations in the few days before delivery of the fetus. To determine the possible role of cortisol in the postnatal change in myocardial growth, we measured DNA and protein concentrations in the free walls of the left (LV) and right (RV) ventricles in normal fetal lambs, normal newborn lambs, and in fetal lambs in which cortisone was infused for 72-80 h into the left coronary artery, which we showed does not perfuse the RV free wall. Normally, fetal RV DNA is higher than LV DNA concentration, and DNA/protein ratio is lower in RV than in LV. It is suggested that this could be related to the greater load on the RV. Postnatally, protein concentrations increase progressively, but DNA remains the same in both ventricles, and protein/DNA ratios increase. Cortisol, infused to achieve normal prenatal levels in LV myocardium, markedly decreases LV DNA without affecting RV DNA concentrations. The present study indicates that cortisol inhibits myocyte replication and that cortisol simulates the change in myocardial growth pattern normally occurring after birth. It raises concerns regarding prenatal administration of glucocorticoids to mothers to mature the fetal lungs before preterm delivery.
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Affiliation(s)
- A M Rudolph
- Department of Pediatrics and Cardiovascular Research Institute, University of California, San Francisco 94143, USA
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Portman MA, Xiao Y, Song Y, Ning XH. Expression of adenine nucleotide translocator parallels maturation of respiratory control in heart in vivo. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:H1977-83. [PMID: 9362269 DOI: 10.1152/ajpheart.1997.273.4.h1977] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Changes in the relationship between myocardial high-energy phosphates and oxygen consumption in vivo occur during development, implying that the mode of respiratory control undergoes maturation. We hypothesized that these maturational changes in sheep heart are paralleled by alterations in the adenine nucleotide translocator (ANT), which are in turn related to changes in the expression of this gene. Increases in myocardial oxygen consumption (MVO2) were induced by epinephrine infusion in newborn (0-32 h, n = 6) and mature sheep (30-32 days, n = 6), and high-energy phosphates were monitored with 31P nuclear magnetic resonance. Western blot analyses for the ANT1 and the beta-subunit of F1-adenosinetriphosphatase (ATPase) were performed in these hearts and additional (n = 9 total per group) as well as in fetal hearts (130-132 days of gestation, n = 5). Northern blot analyses were performed to assess for changes in steady-state RNA transcripts for these two genes. Kinetic analyses for the 31P spectra data revealed that the ADP-MVO2 relationship for the newborns conformed to a Michaelis-Menten model but that the mature data did not conform to first- or second-order kinetic control of respiration through ANT. Maturation from fetal to mature was accompanied by a 2.5-fold increase in ANT protein (by Western blot), with no detectable change in beta-F1-ATPase. Northern blot data show that steady-state mRNA levels for ANT and beta-F1-ATPase increased approximately 2.5-fold from fetal to mature. These data indicate that 1) respiratory control pattern in the newborn is consistent with a kinetic type regulation through ANT, 2) maturational decreases in control through ANT are paralleled by specific increases in ANT content, and 3) regulation of these changes in ANT may be related to increases in steady-state transcript levels for its gene.
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Affiliation(s)
- M A Portman
- Department of Pediatrics, University of Washington School of Medicine and Children's Hospital and Medical Center, Seattle 98195-6320, USA
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Reuss ML, Paneth N, Lorenz JM, Susser M. Correlates of low thyroxine values at newborn screening among infants born before 32 weeks gestation. Early Hum Dev 1997; 47:223-33. [PMID: 9039970 DOI: 10.1016/s0378-3782(96)01843-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We assessed the relation of perinatal factors to severe hypothyroxinemia of prematurity, defined as thyroxine value more than 2.6 standard deviations below the mean for newborns. The 365 survivors of birth before 32 weeks gestation were enrolled in a population-based study of the correlates of neonatal brain injury. In this historical cohort study, mothers were interviewed; perinatal data were abstracted from medical records and neonatal data were collected prospectively. Neonatal thyroxine screening values were retrieved from the New Jersey State Department of Health. Associated with severe hypothyroxinemia were: gestational age 23-27 weeks vs. 31 weeks (OR = 5.1, 95% CI 1.7, 15.2), later age at thyroxine test (OR = 1.6 per day, 95% CI 1.2, 2.1), fraction inspired oxygen at age 24 h > 40% (OR = 3.2, 95% CI 1.1, 8.8), mechanical ventilation (OR = 5.1, 95% CI 1.3, 19.4), diastolic blood pressure < 20 mmHg (OR = 2.3, 95% CI 1.2, 4.3), and > 12 years of maternal education (OR = 0.4, 95% CI 0.22, 1.0). Infants with severe hypothyroxinemia had higher mortality, more days of oxygen supplementation, ventilation and hospitalization and were 11 times more likely to require oxygen supplementation at the postnatal age equivalent to 36 weeks gestational age (odds ratio 10.6, 95% CI 2.3, 48.8). In preterm infants, neonatal thyroxine levels obtained at newborn screening in the first week of life may convey important prognostic information about mortality, morbidity, and the risk for bronchopulmonary dysplasia.
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Affiliation(s)
- M L Reuss
- Bellevue Research Foundation, Bellevue Woman's Hospital, New York, USA
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38
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Abstract
The perspective from which the developing heart is viewed can lead to differing conclusions about the effects of development on cardiac function. The hearts of the embryo, fetus and adult, viewed from a global perspective, sustain the circulation through the same basic mechanisms of developing pressure and ejecting blood. The failure of the embryonic heart to perform these tasks results in growth failure, edema, and embryonic death, just as in the infant and adult such failure results in premature death. Furthermore, from the viewpoint of gross anatomy, following embryonic morphogenesis, the developing and adult hearts appear in general to be structurally similar, differing only in size and mass. However, a closer view shows, in the molecular and structural makeup of the myocardium, richly complex changes that can modulate the basic physiological properties of the cardiac myocyte. This article focuses on how these changes and the effects of birth and development alter ventricular function.
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Affiliation(s)
- P A Anderson
- Department of Pediatric Cardiology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
The rapid initiation of thermogenesis is crucial for the survival of newborn infants. At birth the fetus must adapt to cooling, increased oxygenation and separation from the placenta. An experimental approach in the chronically instrumental fetal sheep of 'simulated birth in utero' allowed the evaluation of each of these stimuli sequentially. Cooling stimulated shivering, cardiovascular and endocrine responses but not nonshivering thermogenesis (NST). Ventilation of the cooled fetus with oxygen caused only modest NST which was not altered by an infusion of triiodothyronine. Occluding the umbilical cord was followed by a rapid substantial rise in NST which was maintained until the placental circulation was re-established. Thus the placenta is secreting factors into the fetal circulation which inhibit the ability of the brown adipose tissue to respond to either hormonal or neural stimuli. Placental prostaglandin E2 and probably adenosine are tonic inhibitors of thermogenesis in utero. Effective thermogenesis after birth requires the combination of separation from the placental inhibitors of lipolysis, increased oxygenation from breathing and the stimulation of cutaneous cold receptors.
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Affiliation(s)
- T R Gunn
- Department of Paediatrics, School of Medicine, University of Auckland, New Zealand
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Tseng YT, Tucker MA, Kashiwai KT, Waschek JA, Padbury JF. Regulation of beta 1-adrenoceptors by glucocorticoids and thyroid hormones in fetal sheep. Eur J Pharmacol 1995; 289:353-9. [PMID: 7621909 DOI: 10.1016/0922-4106(95)90113-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of betamethasone alone or in combination with thyroxine (T4) on ovine fetal beta-adrenoceptors were investigated at the molecular level. Ovine fetuses (126 days gestation; term = 150 days) were treated with a single ultrasound-guided intramuscular injection of 0.5 mg/kg betamethasone, betamethasone + 50 micrograms/kg T4, or saline. Forty-eight h after injection, lambs were delivered by cesarean section and evaluated three h for postnatal adaptation. Myocardial beta-adrenoceptor equilibrium dissociation constant (Kd) and maximal receptor density (Bmax), as assessed by [3H]dihydroalprenolol binding, were not significantly different in drug-treated groups compared to the control group. Northern hybridization and RNase protection assays of myocardial total RNA probed with a sheep beta 1-adrenoceptor riboprobe confirmed no changes in expression at the level of the gene. Levels of beta 1-adrenoceptor mRNA in the lung and brain were also unaffected by the treatments. Because other genes are responsive to glucocorticoids and thyroid hormones at this stage, the absence of up-regulation of beta-adrenoceptor number and steady-state levels of mRNA coding for beta 1-adrenoceptor following fetal corticosteroid and thyroid hormone treatment may indicate a specific, developmentally regulated repressor mechanism.
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Affiliation(s)
- Y T Tseng
- Department of Pediatrics, UCLA School of Medicine, Harbor-UCLA Medical Center, Torrance 90502, USA
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Stein HM, Martinez A, Blount L, Oyama K, Padbury JF. The effects of corticosteroids and thyrotropin-releasing hormone on newborn adaptation and sympathoadrenal mechanisms in preterm sheep. Am J Obstet Gynecol 1994; 171:17-24. [PMID: 8030694 DOI: 10.1016/s0002-9378(94)70071-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES We examined the effect of prenatal corticosteroids and thyrotropin-releasing hormone on postnatal adaptation and sympathoadrenal function in preterm lambs. STUDY DESIGN Catheterized fetal lambs received saline solution (n = 6), corticosteroids alone (n = 8), or corticosteroids plus thyrotropin-releasing hormone (n = 6) for 60 hours. The lambs were delivered by cesarean section at a gestational age of 130 +/- 1 days. Ventilatory, cardiovascular, and metabolic responses and plasma catecholamine concentrations were measured for 2 hours after birth. Statistical analysis was performed by use of independent t tests or analysis of variance. RESULTS Ventilatory function and cardiac contractility were significantly improved in both corticosteroid and corticosteroid plus thyrotropin-releasing hormone animals. Lambs treated with corticosteroid plus thyrotropin-releasing hormone had significantly higher aortic pressure and left ventricular blood pressure than either of the other groups. The postnatal norepinephrine and epinephrine surge was blunted in response to corticosteroid and corticosteroid plus thyrotropin-releasing hormone treatment. There were no differences in metabolic responses among the three groups. CONCLUSIONS In premature lambs prenatal exposure to corticosteroids and thyrotropin-releasing hormone improves postnatal cardiovascular adaptation more than corticosteroids alone.
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Affiliation(s)
- H M Stein
- Department of Pediatrics, UCLA School of Medicine, Harbor-UCLA Medical Center, Torrance 90502
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42
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Affiliation(s)
- D A Fisher
- UCLA School of Medicine, Harbor UCLA Medical Center, Torrance 90509
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43
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Stein HM, Oyama K, Martinez A, Chappell BA, Buhl E, Blount L, Padbury JF. Effects of corticosteroids in preterm sheep on adaptation and sympathoadrenal mechanisms at birth. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 264:E763-9. [PMID: 8388639 DOI: 10.1152/ajpendo.1993.264.5.e763] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study investigates the effects of prenatal corticosteroid administration on newborn sympathoadrenal mechanisms involved in postnatal adaptation. Randomly assigned preterm (122-125 days) fetal sheep were treated with hydrocortisone or saline for 60 h and delivered by cesarean section. We examined postnatal physiological adaptation, sympathoadrenal responses, cardiac beta-receptor density, and the receptor-cyclase system. We observed increased ventilatory, cardiovascular, and metabolic responses function in the corticosteroid-treated animals despite a marked attenuation in the anticipated surge of plasma catecholamine concentrations and a decrease in epinephrine secretion rate, which is normally seen at birth. Myocardial beta-adrenergic receptor density and affinity states were comparable in both groups. Basal and agonist-mediated adenylyl cyclase activity in myocardial tissue was increased in the corticosteroid-treated animals. We speculate that the increase in myocardial adenylyl cyclase activity may be accompanied by similar changes in other organ systems and that this could account for the augmentation in respiratory, cardiovascular, and metabolic responses in the corticosteroid-treated animals.
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Affiliation(s)
- H M Stein
- Department of Pediatrics, Harbor-University of California, Los Angeles School of Medicine, Torrance 90502
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Smolich JJ, Soust M, Berger PJ, Walker AM. Indirect relation between rises in oxygen consumption and left ventricular output at birth in lambs. Circ Res 1992; 71:443-50. [PMID: 1628399 DOI: 10.1161/01.res.71.2.443] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To examine the relation between increased newborn oxygen requirements and the postnatal rise in cardiac output, we measured left ventricular (LV) output, organ blood flows, and whole-body oxygen consumption using radioactive microspheres in late-gestation sheep fetuses and in the same animals 1 and 4 hours after cesarean section delivery. LV output rose from 264 +/- 23 ml.min-1.kg body wt-1 in fetuses to 444 +/- 33 ml.min-1.kg body wt-1 in lambs at 1 hour after delivery (p less than 0.005) and was unchanged at 4 hours after delivery. This rise in LV output was associated with a more than fourfold increase in the LV flow contribution to tissues situated distal to the ductus arteriosus (fetus, 51 +/- 9 ml.min-1.kg body wt-1; lamb, 226 +/- 22 ml.min-1.kg body wt-1; p less than 0.005), which were mainly perfused by the right ventricle in utero. However, average blood flow to body tissues was similar in fetuses (37 +/- 4 ml.min-1.100 g tissue-1), 1-hour lambs (39 +/- 4 ml.min-1.100 g tissue-1), and 4-hour lambs (40 +/- 5 ml.min-1.100 g tissue-1). Oxygen consumption increased by 58%, from 7.84 +/- 0.43 ml.min-1.kg body wt-1 in fetuses to 12.38 +/- 2.4 ml.min-1.kg body wt-1 in 1-hour lambs (p less than 0.01), and was unchanged in 4-hour lambs.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J J Smolich
- Centre for Early Human Development, Monash Medical Centre, Clayton, Australia
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45
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de Zegher F, Spitz B, Devlieger H. Prenatal treatment with thyrotrophin releasing hormone to prevent neonatal respiratory distress. Arch Dis Child 1992; 67:450-4. [PMID: 1316739 PMCID: PMC1590494 DOI: 10.1136/adc.67.4_spec_no.450] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- F de Zegher
- Department of Paediatrics, University Hospital Gasthuisberg, Leuven, Belgium
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Adamson SL, Whiteley KJ, Langille BL. Pulsatile pressure-flow relations and pulse-wave propagation in the umbilical circulation of fetal sheep. Circ Res 1992; 70:761-72. [PMID: 1551202 DOI: 10.1161/01.res.70.4.761] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The relations between pulsatile pressures and flows in the umbilico-placental circulation have been investigated using chronically instrumented fetal sheep. Under resting conditions, mean arterial pressure fell by 30 +/- 6%, from 44 +/- 2 to 31 +/- 2 mm Hg between the aortic termination and the arteries feeding the cotyledons, and pressure waves were substantially damped during propagation between the two recording sites. This high flow resistance and wave attenuation are attributed to the very thick walls and extreme length of the umbilical arteries. Unique relations between pulsatile components of pressure and flow, characterized as vascular impedance spectra, were also observed. At rest, impedance to pulsatile flow was only slightly below resistance to steady flow, and impedance phase was positive at low frequencies. Pulse-wave reflections had more modest effects in this bed than others. Thus, oscillations in impedance spectra and percent wave transmission with increasing frequency, which are widely accepted manifestations of wave reflections, were relatively small. Positive impedance phases at low frequencies indicated that novel mechanisms influence phase relations between pressure and flow. A significant vascular compliance residing in the peripheral vascular beds could account for this findings. The vasodilator nitroprusside enhanced wave-reflection effects, whereas the vasoconstrictor angiotensin II reduced these effects. These changes were opposite to the effects of vasoactive substances in other systems, probably because these drugs act predominantly on the supply (umbilical) arteries rather than on the peripheral placental vasculature. When peripheral vascular resistance was selectively elevated by infusing 50-microns microspheres, reflection effects were enhanced: the pressure pulse in the umbilical artery was transmitted without attenuation, or was amplified, and impedance spectra more closely resembled patterns typical of other vascular beds. Specifically, impedance modulus fell sharply with increasing frequency, and impedance phase was negative at low frequency. In addition, we observed coordinated oscillations in impedance modulus and phase that are characteristic of beds that exhibit wave-reflection effects. These findings indicate that the specialized anatomy and control mechanisms observed in the umbilical circulation result in unique hemodynamic function, in which wave-propagation effects exert influences not readily predictable from studies on other systems.
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Affiliation(s)
- S L Adamson
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada
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47
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Abstract
The aim of this study was to observe the sequential effects of oxygenation, umbilical cord occlusion, and finally cooling on circulating catecholamines and nonshivering thermogenesis in fetal sheep. We studied five fetal sheep at 132 +/- 3 days' gestation. The fetuses were first ventilated with oxygen; PaO2 levels were maintained above 150 mm Hg, and by 60 minutes there was a significant rise in both plasma glycerol and free fatty acid levels. After umbilical cord occlusion there was a peak in plasma catecholamine and triiodothyronine levels but no significant increase in lipolysis. Cooling, by circulating cold water through a coil around the fetus, induced maximum lipolysis and temperature difference between brown fat and body core, when plasma catecholamine levels were falling. During this study the changes in plasma catecholamine levels did not correlate with the onset of nonshivering thermogenesis. Cutaneous cooling, which causes neurally mediated sympathetic stimulation of brown adipose tissue, is the major signal for the initiation of nonshivering thermogenesis and thus neonatal adaptation.
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Fisher DA. Thyroid system ontogeny in the sheep: a model for precocial mammalian species. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 299:11-26. [PMID: 1810131 DOI: 10.1007/978-1-4684-5973-9_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There is now extensive data in two animal models to characterize the events of thyroid system maturation in mammalian species. Data from the rat have contributed importantly to our understanding of thyroid development in the altricial species while studies in the sheep have characterized thyroid ontogenesis in precocial mammals. More limited data are available from human studies and this information, with the animal data, indicate that the major features of thyroid system development are qualitatively similar in all three species. The combined data has provided an important overview of mammalian thyroid ontogenesis. However the picture remains unfinished. We have limited insights into the maturation of the molecular events of hypothalamic pituitary control, the maturation of TSH and thyroid nuclear receptors and postreceptor events, and the mechanisms of the thyroid effects on brain maturation. We can look forward to continuing contributions in these areas.
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Affiliation(s)
- D A Fisher
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance 90509
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49
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Van Hare GF, Hawkins JA, Schmidt KG, Rudolph AM. The effects of increasing mean arterial pressure on left ventricular output in newborn lambs. Circ Res 1990; 67:78-83. [PMID: 2364497 DOI: 10.1161/01.res.67.1.78] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We developed a preparation in which the mean arterial pressure of the newborn lamb is varied with little change in left ventricular preload. Seven lambs underwent balloon atrial septostomy and were instrumented with vascular catheters, an electromagnetic flow transducer on the aorta, and a balloon occluder on the aorta. Four different preload conditions were established by volume infusion or withdrawal. Aortic flow was measured continuously during gradual occlusion of the aorta. Curves relating mean left atrial pressure to stroke volume before balloon inflation showed a plateau, with little increase in stroke volume with increases in atrial pressure above 7 mm Hg. With balloon inflation, stroke volume decreased linearly with increases in mean arterial pressure. Curves relating left atrial pressure to stroke volume constructed at constant mean atrial pressure showed no plateau but showed continued increases in stroke volume as left atrial pressure was increased to 10 mmHg. When mean arterial pressure is constant, the Starling mechanism is operative in newborn left ventricles. The plateau in newborn lamb function curves is due to increases in mean arterial pressure that accompany volume infusion.
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Affiliation(s)
- G F Van Hare
- Cardiovascular Research Institute, University of California, San Francisco 94143
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50
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Birk E, Iwamoto HS, Heymann MA. Hormonal effects on circulatory changes during the perinatal period. BAILLIERE'S CLINICAL ENDOCRINOLOGY AND METABOLISM 1989; 3:795-815. [PMID: 2698156 DOI: 10.1016/s0950-351x(89)80054-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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