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Bentley RET, Hindmarch CCT, Archer SL. Using omics to breathe new life into our understanding of the ductus arteriosus oxygen response. Semin Perinatol 2023; 47:151715. [PMID: 36906478 DOI: 10.1016/j.semperi.2023.151715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
The ductus arteriosus (DA) connects the aorta to the pulmonary artery (PA), directing placentally oxygenated blood away from the developing lungs. High pulmonary vascular resistance and low systemic vascular resistance facilitate shunting of blood in utero from the pulmonary to the systemic circulation through the widely patent DA, thereby optimizing fetal oxygen (O2) delivery. With the transition from fetal (hypoxia) to neonatal (normoxia) oxygen conditions, the DA constricts while the PA dilates. This process often fails in prematurity, promoting congenital heart disease. Impaired O2-responsivness in the DA promotes persistent ductus arteriosus (PDA), the most common form of congenital heart disease. Knowledge of DA oxygen sensing has greatly advanced in the past few decades, however we still lack a complete understanding of the sensing mechanism. The genomic revolution of the past two decades has facilitated unprecedented discovery in every biological system. This review will demonstrate how multiomic integration of data generated from the DA can breathe new life into our understanding of the DA's oxygen response.
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Affiliation(s)
| | - Charles C T Hindmarch
- QCPU, Queen's Cardiopulmonary Unit, Translational Institute of Medicine (TIME), Department of Medicine, Queen's University, Canada; Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Stephen L Archer
- QCPU, Queen's Cardiopulmonary Unit, Translational Institute of Medicine (TIME), Department of Medicine, Queen's University, Canada; Department of Medicine, Queen's University, Kingston, Ontario, Canada.
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The Association between Hemodynamically Significant Patent Ductus Arteriosus and 25-Hydroxyvitamin D Levels in Preterm Infants ≤32 Weeks Gestational Age. Fetal Pediatr Pathol 2023. [PMID: 37477281 DOI: 10.1080/15513815.2023.2178866] [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] [Indexed: 02/24/2023]
Abstract
INTRODUCTION We investigated the relationship between 25-hydroxyvitamin D (25-OHD) levels and the development of hemodynamically significant patent ductus arteriosus (hsPDA) in preterm infants. METHODS Newborns having a gestational age (GA) of ≤32 weeks with hsPDA consisted the study group (n = 25, 20%), while newborns ≤32 weeks of GA without PDA/hsPDA were the control group (n = 97, 80%). RESULTS The study group had lower GA, birth weight (BW) and 25-OHD levels (p < 0.0001, p = 0.002 and p = 0.003, respectively). After adjusting for the effects of GA, BW and the presence of respiratory distress syndrome, multivariable logistic regression analyses demonstrated that preterm infants with low 25-OHD levels were 6.407 (95% CI: 1.656-24.788, p = 0.007) times more likely to experience hsPDA than preterm infants with normal 25-OHD levels. Every 1 ng/mL increase in 25-OHD levels decreased the probability of hsPDA (OR: 0.894, 95% CI: 0.816-0.98, p = 0.016). Conclusion: Low 25-OHD levels may have a role in the development of hsPDA.
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Nagaraj C, Li Y, Tang B, Bordag N, Guntur D, Enyedi P, Olschewski H, Olschewski A. Potassium Channels in the Transition from Fetal to the Neonatal Pulmonary Circulation. Int J Mol Sci 2022; 23:ijms23094681. [PMID: 35563072 PMCID: PMC9106051 DOI: 10.3390/ijms23094681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/12/2022] [Accepted: 04/20/2022] [Indexed: 12/10/2022] Open
Abstract
The transition from the fetal to the neonatal circulation includes dilatation of the pulmonary arteries (PA) and closure of the Ductus Arteriosus Botalli (DAB). The resting membrane potential and various potassium channel activities in smooth muscle cells (SMC) from fetal and neonatal PA and DAB obtained from the same species has not been systematically analyzed. The key issue addressed in this paper is how the resting membrane potential and the whole-cell potassium current (IK) change when PASMC or DABSMC are transitioned from hypoxia, reflecting the fetal state, to normoxia, reflecting the post-partal state. Patch-clamp measurements were employed to characterize whole-cell K+ channel activity in fetal and post-partal (newborn) PASMC and DABSMC. The main finding of this paper is that the SMC from both tissues use a similar set of K+ channels (voltage-dependent (Kv), calcium-sensitive (KCa), TASK-1 and probably also TASK-2 channels); however, their activity level depends on the cell type and the oxygen level. Furthermore, we provide the first evidence for pH-sensitive non-inactivating K+ current in newborn DABSMC and PASMC, suggesting physiologically relevant TASK-1 and TASK-2 channel activity, the latter particularly in the Ductus Arteriosus Botalli.
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Affiliation(s)
- Chandran Nagaraj
- Ludwig Boltzmann Institute for Lung Vascular Research, Neue Stiftingtalstraße 6, 8010 Graz, Austria; (C.N.); (N.B.)
| | - Yingji Li
- Experimental Anaesthesiology, Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria; (Y.L.); (B.T.); (D.G.)
| | - Bi Tang
- Experimental Anaesthesiology, Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria; (Y.L.); (B.T.); (D.G.)
| | - Natalie Bordag
- Ludwig Boltzmann Institute for Lung Vascular Research, Neue Stiftingtalstraße 6, 8010 Graz, Austria; (C.N.); (N.B.)
- Department of Dermatology and Venereology, Medical University of Graz, Auenbruggerplatz 8, 8036 Graz, Austria
| | - Divya Guntur
- Experimental Anaesthesiology, Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria; (Y.L.); (B.T.); (D.G.)
| | - Péter Enyedi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Tűzoltó utca 37-47, 1094 Budapest, Hungary;
| | - Horst Olschewski
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria;
| | - Andrea Olschewski
- Experimental Anaesthesiology, Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria; (Y.L.); (B.T.); (D.G.)
- Correspondence:
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Coceani F. Oxygen sensing in the ductus arteriosus-A unifying vision for two concepts. Br J Pharmacol 2022; 179:3325-3329. [PMID: 35302234 DOI: 10.1111/bph.15828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/03/2022] [Accepted: 02/16/2022] [Indexed: 11/28/2022] Open
Abstract
Closure of the ductus arteriosus at birth is known to be related to the physiological rise in blood oxygen tension. Two main schemes have been proposed to explain the peculiar contraction of the ductus to oxygen, and their function is based on distinct sensor-effector complexes. Specifically, these schemes comprise a cytochrome P450 monooxygenase-endothelin complex or, alternatively, a mitochondrial redox mechanism-voltage gated potassium channel complex. However, it is not clear how these systems may relate to the closure process. Here, it is proposed that they operate jointly within a single functional entity, with their combined activation being required for a full-fledged contraction of the vessel to oxygen. This arrangement is thought to ensure a smooth transition from the powerful relaxant mechanism that is evident through the early postnatal period. Validation of this concept would not only settle a central question in the operation of the ductus but may also afford a broader perspective in any future translational research.
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Affiliation(s)
- Flavio Coceani
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
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Cakir U, Tayman C, Buyuktiryaki M, Unsal H, Ozer Bekmez B. Do Calcium and Potassium Levels Influence Ductal Patency in Preterm Infants? Am J Perinatol 2020; 37:1123-1129. [PMID: 31167236 DOI: 10.1055/s-0039-1692389] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE We investigated the relationship of serum potassium (K+) and ionized calcium (iCa2+) levels with the persistence of ductus arteriosus. STUDY DESIGN This retrospective cohort study included infants with birth weight < 1,500 g and gestational age < 32 weeks. Serum K+ and iCa2+ levels at the 1st and 48th hour of life were measured from samples. The difference between the two levels was calculated for both serum K+ (ΔK+) and iCa2+ (ΔCa2+). These values were compared between hemodynamically significant patent ductus arteriosus (hsPDA) and non-hsPDA. RESULTS Of 1,322 hospitalized preterm nonates, 1,196 were included in the study. Mean serum K+ levels at the 1st and 48th hour were higher and iCa2+ levels at the 1st and 48th hour were lower in hsPDA and non-hsPDA, respectively (p < 0.001). Ionized ΔCa2+ (-0.06 ± 0.13 vs. -0.02 ± 0.12 mmol/L) was higher in hsPDA (p < 0.001). CONCLUSION We demonstrated that serum K+ and iCa2+ level might play a role in ductal constriction.
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Affiliation(s)
- Ufuk Cakir
- Division of Neonatology, Health Sciences University, Zekai Tahir Burak Maternity, Education and Research Hospital, Ankara, Turkey
| | - Cuneyt Tayman
- Division of Neonatology, Health Sciences University, Zekai Tahir Burak Maternity, Education and Research Hospital, Ankara, Turkey
| | - Mehmet Buyuktiryaki
- Division of Neonatology, Health Sciences University, Zekai Tahir Burak Maternity, Education and Research Hospital, Ankara, Turkey
| | - Handan Unsal
- Department of Pediatric Cardiology, Health Sciences University, Zekai Tahir Burak Maternity, Education, and Research Hospital, Ankara, Turkey
| | - Buse Ozer Bekmez
- Division of Neonatology, Health Sciences University, Zekai Tahir Burak Maternity, Education and Research Hospital, Ankara, Turkey
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Ovalı F. Molecular and Mechanical Mechanisms Regulating Ductus Arteriosus Closure in Preterm Infants. Front Pediatr 2020; 8:516. [PMID: 32984222 PMCID: PMC7477801 DOI: 10.3389/fped.2020.00516] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 07/21/2020] [Indexed: 12/14/2022] Open
Abstract
Failure of ductus arteriosus closure after preterm birth is associated with significant morbidities. Ductal closure requires and is regulated by a complex interplay of molecular and mechanical mechanisms with underlying genetic factors. In utero patency of the ductus is maintained by low oxygen tension, high levels of prostaglandins, nitric oxide and carbon monoxide. After birth, ductal closure occurs first by functional closure, followed by anatomical remodeling. High oxygen tension and decreased prostaglandin levels mediated by numerous factors including potassium channels, endothelin-1, isoprostanes lead to the contraction of the ductus. Bradykinin and corticosteroids also induce ductal constriction by attenuating the sensitivity of the ductus to PGE2. Smooth muscle cells of the ductus can sense oxygen through a mitochondrial network by the role of Rho-kinase pathway which ends up with increased intracellular calcium levels and contraction of myosin light chains. Anatomical closure of the ductus is also complex with various mechanisms such as migration and proliferation of smooth muscle cells, extracellular matrix production, endothelial cell proliferation which mediate cushion formation with the interaction of blood cells. Regulation of vessel walls is affected by retinoic acid, TGF-β1, notch signaling, hyaluronan, fibronectin, chondroitin sulfate, elastin, and vascular endothelial cell growth factor (VEGF). Formation of the platelet plug facilitates luminal remodeling by the obstruction of the constricted ductal lumen. Vasa vasorum are more pronounced in the term ductus but are less active in the preterm ductus. More than 100 genes are effective in the prostaglandin pathway or in vascular smooth muscle development and structure may affect the patency of ductus. Hemodynamic changes after birth including fluid load and flow characteristics as well as shear forces within the ductus also stimulate closure. Current pharmacological treatment for the closure of a patent ductus is based on the blockage of the prostaglandin pathway mainly through COX or POX inhibition, albeit with some limitations and side effects. Further research for new agents aiming ductal closure should focus on a clear understanding of vascular biology of the ductus.
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Affiliation(s)
- Fahri Ovalı
- Division of Neonatology, Department of Pediatrics, Istanbul Medeniyet University, Istanbul, Turkey
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Villamor E, Moreno L, Mohammed R, Pérez-Vizcaíno F, Cogolludo A. Reactive oxygen species as mediators of oxygen signaling during fetal-to-neonatal circulatory transition. Free Radic Biol Med 2019; 142:82-96. [PMID: 30995535 DOI: 10.1016/j.freeradbiomed.2019.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/22/2019] [Accepted: 04/08/2019] [Indexed: 12/20/2022]
Abstract
Reactive oxygen species (ROS) are frequently seen as pathological agents of oxidative stress. However, ROS are not always deleterious and can also act as cell signaling molecules. Vascular oxygen sensing and signaling during fetal-to-neonatal circulatory transition is a remarkable example of the physiological regulatory actions of ROS. The fetal relative hypoxic environment induces hypoxic pulmonary vasoconstriction (HPV) and ductus arteriosus (DA) relaxation favoring the presence of high pulmonary vascular resistance and right-to-left ductal shunt. At birth, the increase in oxygen tension causes relaxation of pulmonary arteries (PAs) and normoxic DA vasoconstriction (NDAV), thus diverting blood flow to the lungs. Although the response to changes in oxygen tension is diametrically opposite, the mechanisms responsible for HPV and NDAV appear to be the result of a similar interaction between triggering and modulating factors that lead to an increase in cytosolic Ca2+ concentration and Ca2+ sensitization of the contractile apparatus. Growing evidence points to an increase in ROS (mitochondria- and/or NADPH-derived superoxide and/or H2O2), leading to inhibition of voltage-gated K+ channels, membrane depolarization, and activation of voltage-gated L-type Ca2+ channels as critical events in the signaling pathway of both HPV and NDAV. Several groups of investigators have completed this pathway adding other elements such as neutral sphingomyelinase-derived ceramide, the sarcoplasmic/endoplasmic reticulum (through ryanodine and inositol 1,4,5-trisphosphate receptors), Rho kinase-mediated Ca2+ sensitization, or transient receptor potential channels. The present review focus on the role of ROS as mediators of the homeostatic oxygen sensing system during fetal and neonatal life not only in the PAs and DA but also in systemic arteries.
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Affiliation(s)
- Eduardo Villamor
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Maastricht, the Netherlands.
| | - Laura Moreno
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Riazzudin Mohammed
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Maastricht, the Netherlands
| | - Francisco Pérez-Vizcaíno
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Angel Cogolludo
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
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Understanding the pathobiology in patent ductus arteriosus in prematurity-beyond prostaglandins and oxygen. Pediatr Res 2019; 86:28-38. [PMID: 30965358 DOI: 10.1038/s41390-019-0387-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/05/2019] [Accepted: 03/27/2019] [Indexed: 12/14/2022]
Abstract
The ductus arteriosus (DA) is probably the most intriguing vessel in postnatal hemodynamic transition. DA patency in utero is an active state, in which prostaglandin E2 (PGE2) and nitric monoxide (NO), play an important role. Since the DA gets programmed for postnatal closure as gestation advances, in preterm infants the DA frequently remains patent (PDA). PGE2 exposure programs functional postnatal closure by inducing gene expression of ion channels and phosphodiesterases and anatomical closure by inducing intimal thickening. Postnatally, oxygen inhibits potassium and activates calcium channels, which ultimately leads to a rise in intracellular calcium concentration consequently inducing phosphorylation of the myosin light chain and thereby vasoconstriction of the DA. Since ion channel expression is lower in preterm infants, oxygen induced functional vasoconstriction is attenuated in comparison with full term newborns. Furthermore, the preterm DA is more sensitive to both PGE2 and NO compared to the term DA pushing the balance toward less constriction. In this review we explain the physiology of DA patency in utero and subsequent postnatal functional closure. We will focus on the pathobiology of PDA in preterm infants and the (un)intended effect of antenatal exposure to medication on both fetal and neonatal DA vascular tone.
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Cogolludo A, Villamor E, Perez-Vizcaino F, Moreno L. Ceramide and Regulation of Vascular Tone. Int J Mol Sci 2019; 20:ijms20020411. [PMID: 30669371 PMCID: PMC6359388 DOI: 10.3390/ijms20020411] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/02/2019] [Accepted: 01/16/2019] [Indexed: 02/07/2023] Open
Abstract
In addition to playing a role as a structural component of cellular membranes, ceramide is now clearly recognized as a bioactive lipid implicated in a variety of physiological functions. This review aims to provide updated information on the role of ceramide in the regulation of vascular tone. Ceramide may induce vasodilator or vasoconstrictor effects by interacting with several signaling pathways in endothelial and smooth muscle cells. There is a clear, albeit complex, interaction between ceramide and redox signaling. In fact, reactive oxygen species (ROS) activate different ceramide generating pathways and, conversely, ceramide is known to increase ROS production. In recent years, ceramide has emerged as a novel key player in oxygen sensing in vascular cells and mediating vascular responses of crucial physiological relevance such as hypoxic pulmonary vasoconstriction (HPV) or normoxic ductus arteriosus constriction. Likewise, a growing body of evidence over the last years suggests that exaggerated production of vascular ceramide may have detrimental effects in a number of pathological processes including cardiovascular and lung diseases.
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Affiliation(s)
- Angel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, 28040 Madrid, Spain.
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain.
| | - Eduardo Villamor
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), 6202 AZ Maastricht, The Netherlands.
| | - Francisco Perez-Vizcaino
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, 28040 Madrid, Spain.
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain.
| | - Laura Moreno
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, 28040 Madrid, Spain.
- Ciber Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain.
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Hsieh ML, Liu PY, Wu JM, Liao JK, Wang JN. Interventional Transcatheter Closure Ameliorates the Leukocyte Rho Kinase Activities among Patients with Patent Ductus Arteriosus. ACTA CARDIOLOGICA SINICA 2016; 31:494-9. [PMID: 27122913 DOI: 10.6515/acs20150424d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Patent ductus arteriosus (PDA) causes increased pulmonary blood flow, which can lead to pulmonary arterial hypertension (PAH). Rho-associated coiled-coil containing protein kinase (ROCK) may play an important pathophysiological role in PAH. We hypothesized that the increased pulmonary artery (PA) flow from PDA could activate ROCK. METHODS Patients who received a PDA transcatheter closure in our hospital were consecutively enrolled in this study. Basic demographics and clinical hemodynamic data of the study participants were recorded. Then, ROCK activity was measured before and after the PDA occlusion procedure. ROCK activity was defined as the phosphorylation ratio of myosin-binding subunit by Western blot measurement. We also sub-divided patients into the coil group and occluder group based on the occlusion device used in each patient's procedure. RESULTS From January 2009 to December 2011, 25 patients with a median age of 2.3 years, ranging from 10 months to 72 years were enrolled. The mean PDA size was 0.31 ± 0.14 cm, the mean Qp/Qs shunt was 1.54 ± 0.41, and the mean systolic pulmonary artery pressure was 26.9 ± 10.3 mmHg. There were 10 patients (one boy and nine girls) in the coil group and 15 patients (four boys and eleven girls) in the occluder group. Following the closure of the PDA, ROCK activity significantly decreased (1.78 ± 2.25 vs. 0.77 ± 0.69, p < 0.01). There was a strong correlation between the leukocyte ROCK activity with the systolic PA pressure (y = 5.4608x + 22.54, R2 = 0.5539, p < 0.05), but not the Qp/Qs value. Both subgroups showed significant changes of ROCK activity after the procedure. Interestingly, when comparing the coil group with the occluder group, the decrease in ROCK activity was more apparent in the occluder group. CONCLUSIONS The findings of this study indicated that ROCK activity is higher in patients with PDA and correlates with PA pressure. The decrease in ROCK activity following the device closure suggests that ROCK may be an important biomarker for PDA patency. KEY WORDS Patent ductus arteriosus (PDA); Pulmonary arterial pressure; Rho kinase; Transcatheter closure.
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Affiliation(s)
| | - Ping-Yen Liu
- Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; ; Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | | | - James K Liao
- Division of Cardiology, University of Chicago, Chicago, IL, USA
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Aoki R, Yokoyama U, Ichikawa Y, Taguri M, Kumagaya S, Ishiwata R, Yanai C, Fujita S, Umemura M, Fujita T, Okumura S, Sato M, Minamisawa S, Asou T, Masuda M, Iwasaki S, Nishimaki S, Seki K, Yokota S, Ishikawa Y. Decreased serum osmolality promotes ductus arteriosus constriction. Cardiovasc Res 2014; 104:326-36. [PMID: 25190043 DOI: 10.1093/cvr/cvu199] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
AIMS At birth, dynamic changes occur in serum components and haemodynamics, such as closure of the ductus arteriosus (DA). A previous study demonstrated that, in full-term human neonates, serum osmolality decreased transiently after birth, but recovered over the next few days. However, the significance of this transient decrease in osmolality has never been addressed. The objective of the present study was to examine the role of changes in serum osmolality after birth in DA closure. METHODS AND RESULTS We found that rats exhibited a similar transient hypoosmolality after birth. Hypotonic stimulation induced constriction of DA rings and increased Ca(2+) transient in DA smooth muscle cells, but not in the aorta. The hypoosmotic sensor transient receptor potential melastatin 3 (TRPM3) was highly expressed in the rat DA, and TRPM3 silencing abolished the Ca(2+) response to hypoosmolality. Pregnenolone sulfate stimulation of TRPM3 induced rat DA constriction ex vivo and in vivo. Furthermore, hypertonic fluid injection impaired rat DA closure. In humans, neonatal serum hypoosmolality was observed in relatively mature preterm infants (≥28 weeks). In extremely preterm infants (<28 weeks), however, this hypoosmolality was absent. Instead, a rapid increase in osmolality occurred thereafter. Such an increase was greater, in particular, among patent DA (PDA) patients. CONCLUSIONS A transient decrease in serum osmolality may promote DA closure during the first few days of life. Adjusting serum osmolality to proper levels might help to prevent the onset of PDA, improving the therapeutic outcome in extremely preterm infants.
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Affiliation(s)
- Rika Aoki
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan Department of Pediatrics, Yokohama City University, Yokohama, Japan
| | - Utako Yokoyama
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
| | - Yasuhiro Ichikawa
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan Department of Pediatrics, Yokohama City University, Yokohama, Japan
| | - Masataka Taguri
- Department of Biostatistics and Epidemiology, Yokohama City University, Yokohama, Japan
| | - Shun Kumagaya
- Department of Life Science and Medical Bioscience, Waseda University Graduate School of Advanced Science and Engineering, Tokyo, Japan
| | - Ryo Ishiwata
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
| | - Chiharu Yanai
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
| | - Shujiro Fujita
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan Department of Pediatrics, Yokohama City University, Yokohama, Japan
| | - Masanari Umemura
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
| | - Takayuki Fujita
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
| | - Satoshi Okumura
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Motohiko Sato
- Department of Physiology, Aichi Medical University, Nagakute, Japan
| | - Susumu Minamisawa
- Department of Life Science and Medical Bioscience, Waseda University Graduate School of Advanced Science and Engineering, Tokyo, Japan Department of Cell Physiology, Jikei University School of Medicine, Tokyo, Japan
| | - Toshihide Asou
- Department of Cardiovascular Surgery, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Munetaka Masuda
- Department of Surgery, Yokohama City University, Yokohama, Japan
| | - Shiho Iwasaki
- Department of Pediatrics, Yokohama City University, Yokohama, Japan
| | | | - Kazuo Seki
- Department of Pediatrics, Yokohama City University, Yokohama, Japan
| | - Shumpei Yokota
- Department of Pediatrics, Yokohama City University, Yokohama, Japan
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
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Hong Z, Cabrera JA, Mahapatra S, Kutty S, Weir EK, Archer SL. Activation of the EGFR/p38/JNK pathway by mitochondrial-derived hydrogen peroxide contributes to oxygen-induced contraction of ductus arteriosus. J Mol Med (Berl) 2014; 92:995-1007. [PMID: 24906456 DOI: 10.1007/s00109-014-1162-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/25/2014] [Accepted: 04/29/2014] [Indexed: 12/17/2022]
Abstract
UNLABELLED Oxygen-induced contraction of the ductus arteriosus (DA) involves a mitochondrial oxygen sensor, which signals pO2 in the DA smooth muscle cell (DASMC) by increasing production of diffusible hydrogen peroxide (H2O2). H2O2 stimulates vasoconstriction by regulating ion channels and Rho kinase, leading to calcium influx and calcium sensitization. Because epidermal growth factor receptor (EGFR) signaling is also redox regulated and participates in oxygen sensing and vasoconstriction in other systems, we explored the role of the EGFR and its signaling cascade (p38 and c-Jun N-amino-terminal kinase (JNK)) in DA contraction. Experiments were performed in DA rings isolated from full-term New Zealand white rabbits and human DASMC. In human DASMCs, increasing pO2 from hypoxia to normoxia (40 to 100 mmHg) significantly increased cytosolic calcium, p < 0.01. This normoxic rise in intracellular calcium was mimicked by EGF and inhibited by EGFR siRNA. In DA rings, EGF caused contraction while the specific EGFR inhibitor (AG1478) and the tyrosine kinase inhibitors (genistein or tyrphostin A23) selectively attenuated oxygen-induced contraction (p < 0.01). Conversely, orthovanadate, a tyrosine phosphatase inhibitor known to activate EGFR signaling, caused dose-dependent contraction of hypoxic DA and superimposed increases in oxygen caused minimal additional contraction. Anisomycin, an activator of EGFR's downstream kinases, p38 and JNK, caused DA contraction; conversely, oxygen-induced DA contraction was blocked by inhibitors of p38 mitogen-activated protein kinases (MAPK) (SB203580) or JNK (JNK inhibitor II). O2-induced phosphorylation of EGFR occurred within 5 min of increasing pO2 and was inhibited by mitochondrial-targeted overexpression of catalase. AG1478 prevented the oxygen-induced p38 and JNK phosphorylation. In conclusion, O2-induced EGFR transactivation initiates p38/JNK-mediated increases in cytosolic calcium and contributes to DA contraction. The EGFR/p38/JNK pathway is regulated by mitochondrial redox signaling and is a promising therapeutic target for modulation of the patent ductus arteriosus. KEY MESSAGES Oxygen activates epidermal growth factor receptor (EGFR) in ductus arteriosus (DA) smooth muscle cells. EGFR inhibition selectively attenuates O2-induced DA constriction. pO2-induced EGFR activation is mediated by mitochondrial-derived hydrogen peroxide. p38 MAPK and JNK mediated EGFR's effects on oxygen-induced DA contraction. Tyrosine kinases and phosphatases participate in oxygen sensing in the DA. The EGFR pathway offers new therapeutic targets to modulate patency of the ductus arteriosus.
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Affiliation(s)
- Zhigang Hong
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St., Kingston, Ontario, K7L 3 N6, Canada
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13
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Abstract
Successful transition from intrauterine to extrauterine life involves significant physiologic changes. The majority of these changes occur relatively quickly during those first moments following delivery; however, transition for the extremely preterm infant occurs over a longer period of time. Careful assessment and perceptive interventions on the part of neonatal care providers is essential as the extremely preterm infant adjusts to life outside the womb. This article will focus on respiratory, cardiovascular, gastrointestinal, and neurologic transitional events experienced by the extremely premature infant.
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Bökenkamp R, van Brempt R, van Munsteren JC, van den Wijngaert I, de Hoogt R, Finos L, Goeman J, Groot ACGD, Poelmann RE, Blom NA, DeRuiter MC. Dlx1 and Rgs5 in the ductus arteriosus: vessel-specific genes identified by transcriptional profiling of laser-capture microdissected endothelial and smooth muscle cells. PLoS One 2014; 9:e86892. [PMID: 24489801 PMCID: PMC3904938 DOI: 10.1371/journal.pone.0086892] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 12/17/2013] [Indexed: 12/31/2022] Open
Abstract
Closure of the ductus arteriosus (DA) is a crucial step in the transition from fetal to postnatal life. Patent DA is one of the most common cardiovascular anomalies in children with significant clinical consequences especially in premature infants. We aimed to identify genes that specify the DA in the fetus and differentiate it from the aorta. Comparative microarray analysis of laser-captured microdissected endothelial (ECs) and vascular smooth muscle cells (SMCs) from the DA and aorta of fetal rats (embryonic day 18 and 21) identified vessel-specific transcriptional profiles. We found a strong age-dependency of gene expression. Among the genes that were upregulated in the DA the regulator of the G-protein coupled receptor 5 (Rgs5) and the transcription factor distal-less homeobox 1 (Dlx1) exhibited the highest and most significant level of differential expression. The aorta showed a significant preferential expression of the Purkinje cell protein 4 (Pcp4) gene. The results of the microarray analysis were validated by real-time quantitative PCR and immunohistochemistry. Our study confirms vessel-specific transcriptional profiles in ECs and SMCs of rat DA and aorta. Rgs5 and Dlx1 represent novel molecular targets for the regulation of DA maturation and closure.
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Affiliation(s)
- Regina Bökenkamp
- Department of Pediatric Cardiology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
| | - Ronald van Brempt
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands
- Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | | | | | - Ronald de Hoogt
- Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - Livio Finos
- Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jelle Goeman
- Biostatistics, Department for Health Evidence, Radboud University Medical Center, Nimegen, The Netherlands
| | - Adriana Cornelia Gittenberger-de Groot
- Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert Eugen Poelmann
- Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Nicolaas Andreas Blom
- Department of Pediatric Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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15
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Moreno L, Moral-Sanz J, Morales-Cano D, Barreira B, Moreno E, Ferrarini A, Pandolfi R, Ruperez FJ, Cortijo J, Sanchez-Luna M, Villamor E, Perez-Vizcaino F, Cogolludo A. Ceramide mediates acute oxygen sensing in vascular tissues. Antioxid Redox Signal 2014; 20:1-14. [PMID: 23725018 PMCID: PMC3880904 DOI: 10.1089/ars.2012.4752] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIMS A variety of vessels, such as resistance pulmonary arteries (PA) and fetoplacental arteries and the ductus arteriosus (DA) are specialized in sensing and responding to changes in oxygen tension. Despite opposite stimuli, normoxic DA contraction and hypoxic fetoplacental and PA vasoconstriction share some mechanistic features. Activation of neutral sphingomyelinase (nSMase) and subsequent ceramide production has been involved in hypoxic pulmonary vasoconstriction (HPV). Herein we aimed to study the possible role of nSMase-derived ceramide as a common factor in the acute oxygen-sensing function of specialized vascular tissues. RESULTS The nSMase inhibitor GW4869 and an anticeramide antibody reduced the hypoxic vasoconstriction in chicken PA and chorioallantoic arteries (CA) and the normoxic contraction of chicken DA. Incubation with interference RNA targeted to SMPD3 also inhibited HPV. Moreover, ceramide and reactive oxygen species production were increased by hypoxia in PA and by normoxia in DA. Either bacterial sphingomyelinase or ceramide mimicked the contractile responses of hypoxia in PA and CA and those of normoxia in the DA. Furthermore, ceramide inhibited voltage-gated potassium currents present in smooth muscle cells from PA and DA. Finally, the role of nSMase in acute oxygen sensing was also observed in human PA and DA. INNOVATION These data provide evidence for the proposal that nSMase-derived ceramide is a critical player in acute oxygen-sensing in specialized vascular tissues. CONCLUSION Our results indicate that an increase in ceramide generation is involved in the vasoconstrictor responses induced by two opposite stimuli, such as hypoxia (in PA and CA) and normoxia (in DA).
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Affiliation(s)
- Laura Moreno
- 1 Department of Pharmacology, School of Medicine, Universidad Complutense Madrid , Madrid, Spain
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16
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Sharp WW, Fang YH, Han M, Zhang HJ, Hong Z, Banathy A, Morrow E, Ryan JJ, Archer SL. Dynamin-related protein 1 (Drp1)-mediated diastolic dysfunction in myocardial ischemia-reperfusion injury: therapeutic benefits of Drp1 inhibition to reduce mitochondrial fission. FASEB J 2013; 28:316-26. [PMID: 24076965 DOI: 10.1096/fj.12-226225] [Citation(s) in RCA: 273] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mitochondrial fission, regulated by dynamin-related protein-1 (Drp1), is a newly recognized determinant of mitochondrial function, but its contribution to left ventricular (LV) impairment following ischemia-reperfusion (IR) injury is unknown. We report that Drp1 activation during IR results in LV dysfunction and that Drp1 inhibition is beneficial. In both isolated neonatal murine cardiomyocytes and adult rat hearts (Langendorff preparation) mitochondrial fragmentation and swelling occurred within 30 min of IR. Drp1-S637 (serine 637) dephosphorylation resulted in Drp1 mitochondrial translocation and increased mitochondrial fission. The Drp1 inhibitor Mdivi-1 preserved mitochondrial morphology, reduced cytosolic calcium, and prevented cell death. Drp1 siRNA similarly preserved mitochondrial morphology. In Langendorff hearts, Mdivi-1 reduced mitochondrial reactive oxygen species, improved LV developed pressure (92±5 vs. 28±10 mmHg, P<0.001), and lowered LV end diastolic pressure (10±1 vs. 86±13 mmHg, P<0.001) following IR. Mdivi-1 was protective if administered prior to or following ischemia. Because Drp1-S637 dephosphorylation is calcineurin sensitive, we assessed the effects of a calcineurin inhibitor, FK506. FK506 treatment prior to IR prevented Drp1-S637 dephosphorylation and preserved cardiac function. Likewise, therapeutic hypothermia (30°C) inhibited Drp1-S637 dephosphorylation and preserved mitochondrial morphology and myocardial function. Drp1 inhibition is a novel strategy to improve myocardial function following IR.
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Affiliation(s)
- Willard W Sharp
- 1Section of Emergency Medicine, Department of Medicine, 5841 S. Maryland Ave., MC 5068, Chicago, IL 60637, USA.
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17
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Hong Z, Kutty S, Toth PT, Marsboom G, Hammel JM, Chamberlain C, Ryan JJ, Zhang HJ, Sharp WW, Morrow E, Trivedi K, Weir EK, Archer SL. Role of dynamin-related protein 1 (Drp1)-mediated mitochondrial fission in oxygen sensing and constriction of the ductus arteriosus. Circ Res 2013; 112:802-15. [PMID: 23334860 DOI: 10.1161/circresaha.111.300285] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
RATIONALE Closure of the ductus arteriosus (DA) is essential for the transition from fetal to neonatal patterns of circulation. Initial PO2-dependent vasoconstriction causes functional DA closure within minutes. Within days a fibrogenic, proliferative mechanism causes anatomic closure. Though modulated by endothelial-derived vasodilators and constrictors, O2 sensing is intrinsic to ductal smooth muscle cells and oxygen-induced DA constriction persists in the absence of endothelium, endothelin, and cyclooxygenase mediators. O2 increases mitochondrial-derived H2O2, which constricts ductal smooth muscle cells by raising intracellular calcium and activating rho kinase. However, the mechanism by which oxygen changes mitochondrial function is unknown. OBJECTIVE The purpose of this study was to determine whether mitochondrial fission is crucial for O2-induced DA constriction and closure. METHODS AND RESULTS Using DA harvested from 30 term infants during correction of congenital heart disease, as well as DA from term rabbits, we demonstrate that mitochondrial fission is crucial for O2-induced constriction and closure. O2 rapidly (<5 minutes) causes mitochondrial fission by a cyclin-dependent kinase- mediated phosphorylation of dynamin-related protein 1 (Drp1) at serine 616. Fission triggers a metabolic shift in the ductal smooth muscle cells that activates pyruvate dehydrogenase and increases mitochondrial H2O2 production. Subsequently, fission increases complex I activity. Mitochondrial-targeted catalase overexpression eliminates PO2-induced increases in mitochondrial-derived H2O2 and cytosolic calcium. The small molecule Drp1 inhibitor, Mdivi-1, and siDRP1 yield concordant results, inhibiting O2-induced constriction (without altering the response to phenylephrine or KCl) and preventing O2-induced increases in oxidative metabolism, cytosolic calcium, and ductal smooth muscle cells proliferation. Prolonged Drp1 inhibition reduces DA closure in a tissue culture model. CONCLUSIONS Mitochondrial fission is an obligatory, early step in mammalian O2 sensing and offers a promising target for modulating DA patency.
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Affiliation(s)
- Zhigang Hong
- Department of Medicine, Queen's University, 94 Stuart St, Kingston, Ontario, Canada
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18
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Antenatal calcium channel blocker exposure and subsequent patent ductus arteriosus in extremely low-birth-weight infants. Pediatr Cardiol 2012; 33:60-4. [PMID: 21861146 DOI: 10.1007/s00246-011-0082-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 07/26/2011] [Indexed: 10/17/2022]
Abstract
This study aimed to assess whether tocolytic fetal exposure to antenatal calcium channel blockers (aCCB) increases the risk for hemodynamically significant patent ductus arteriosus (hsPDA) in extremely low-birth-weight (ELBW) infants. This case-control study investigated ELBW infants (<1,000 g) without cardiac defects in a level 3 neonatal intensive care unit who had survived at least 7 days. Nifedipine was the only aCCB used for this study population. The measurements included the history of aCCB exposure, selected maternal data, hsPDA diagnosis, gestational age at birth, birth weight, mode of delivery, sex, maternal race, location of birth, Apgar scores, and selected neonatal morbidities. The end point of the study was hsPDA, defined as an echocardiographically confirmed PDA with clinical symptoms. A total of 180 infants met the study criteria. The diagnosis was hsPDA for 56% of these patients, 20% of whom had aCCB exposure. Of the infants without hsPDA, 11% had aCCB exposure (p = 0.09). No statistically significant associations were found between aCCB exposure and hsPDA after adjustment for gestational age (odds ratio [OR], 1.5; 95% confidence interval [CI], 0.6-3.7) or for gestational age and cumulative aCCB exposure of 100 mg or more (OR, 2.0; 95% CI, 0.6-6.5). A history of aCCB exposure does not appear to increase hsPDA risk in ELBW infants. Studies using neonatal serum nifedipine concentrations after antenatal exposure should be performed to confirm this conclusion.
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Stoller JZ, Demauro SB, Dagle JM, Reese J. Current Perspectives on Pathobiology of the Ductus Arteriosus. ACTA ACUST UNITED AC 2012; 8. [PMID: 23519783 DOI: 10.4172/2155-9880.s8-001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The ductus arteriosus (DA) shunts blood away from the lungs during fetal life, but at birth this shunt is no longer needed and the vessel rapidly constricts. Postnatal persistence of the DA, patent ductus arteriosus (PDA), is predominantly a detrimental condition for preterm infants but is simultaneously a condition required to maintain systemic blood flow for infants born with certain severe congenital heart defects. Although PDA in preterm infants is associated with significant morbidities, there is controversy regarding whether PDA is truly causative. Despite advances in our understanding of the pathobiology of PDA, the optimal treatment strategy for PDA in preterm infants is unclear. Here we review recent studies that have continued to elucidate the fundamental mechanisms of DA development and pathogenesis.
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Affiliation(s)
- Jason Z Stoller
- Department of Pediatrics, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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20
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Goswami SK, Das DK. Oxygen Sensing, Cardiac Ischemia, HIF-1α and Some Emerging Concepts. Curr Cardiol Rev 2011; 6:265-73. [PMID: 22043202 PMCID: PMC3083807 DOI: 10.2174/157340310793566136] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 09/03/2010] [Accepted: 09/15/2010] [Indexed: 11/22/2022] Open
Abstract
Oxygen plays a critical role in the perpetuation and propagation of almost all forms of life. The primary site of cellular oxygen consumption is the mitochondrial electron transport chain and in addition, oxygen is also used as a substrate for various enzymes involved in cellular homeostasis. Although our knowledge of the biochemistry and physiology of oxygen transport is century old, recent development of sophisticated tools of biophysical chemistry revealed that tissue oxygenation and oxygen sensing is a highly evolved process, especially in mammals. Perturbation of normal oxygen supply is associated with diseases like tumorigenesis, myocardial infarction and stroke. Available information suggests that when tissue oxygen supply is limited, mitochondria emanate signals involving reactive oxygen species generation which in turn stabilizes oxygen sensing transcription factor HIF-1. Upon stabilization, HIF-1 elicits necessary genetic response to cope with the diminished oxygen level. In view of such critical role of HIF-1 in cellular oxygen sensing, recently there has been a heightened interest in understanding the biology of HIF-1 in the context of cardiovascular system. The following review describes some of the recent advances in this regard.
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Affiliation(s)
- Shyamal K Goswami
- Cardiovascular Research Center, University of Connecticut School of Medicine, Farmington, Connecticut, CT 06030- 1110, USA
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21
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Koos BJ. Adenosine A₂a receptors and O₂ sensing in development. Am J Physiol Regul Integr Comp Physiol 2011; 301:R601-22. [PMID: 21677265 DOI: 10.1152/ajpregu.00664.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Reduced mitochondrial oxidative phosphorylation, via activation of adenylate kinase and the resulting exponential rise in the cellular AMP/ATP ratio, appears to be a critical factor underlying O₂ sensing in many chemoreceptive tissues in mammals. The elevated AMP/ATP ratio, in turn, activates key enzymes that are involved in physiologic adjustments that tend to balance ATP supply and demand. An example is the conversion of AMP to adenosine via 5'-nucleotidase and the resulting activation of adenosine A(₂A) receptors, which are involved in acute oxygen sensing by both carotid bodies and the brain. In fetal sheep, A(₂A) receptors associated with carotid bodies trigger hypoxic cardiovascular chemoreflexes, while central A(₂A) receptors mediate hypoxic inhibition of breathing and rapid eye movements. A(₂A) receptors are also involved in hypoxic regulation of fetal endocrine systems, metabolism, and vascular tone. In developing lambs, A(₂A) receptors play virtually no role in O₂ sensing by the carotid bodies, but brain A(₂A) receptors remain critically involved in the roll-off ventilatory response to hypoxia. In adult mammals, A(₂A) receptors have been implicated in O₂ sensing by carotid glomus cells, while central A(₂A) receptors likely blunt hypoxic hyperventilation. In conclusion, A(₂A) receptors are crucially involved in the transduction mechanisms of O₂ sensing in fetal carotid bodies and brains. Postnatally, central A(₂A) receptors remain key mediators of hypoxic respiratory depression, but they are less critical for O₂ sensing in carotid chemoreceptors, particularly in developing lambs.
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Affiliation(s)
- Brian J Koos
- Department of Obstetrics and Gynecology; Brain Research Institute, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA.
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22
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Waleh N, Hodnick R, Jhaveri N, McConaghy S, Dagle J, Seidner S, McCurnin D, Murray JC, Ohls R, Clyman RI. Patterns of gene expression in the ductus arteriosus are related to environmental and genetic risk factors for persistent ductus patency. Pediatr Res 2010; 68:292-7. [PMID: 20581741 PMCID: PMC2940964 DOI: 10.1203/pdr.0b013e3181ed8609] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Three independent risk factors (immature gestation, absence of antenatal glucocorticoid exposure, and presence of the rs2817399(A) allele of the gene TFAP2B) are associated with patent ductus arteriosus (PDAs) that fail to close during prostaglandin inhibition. We hypothesized that these three factors may affect a common set of genes that increase the risk of persistent PDA after birth. We studied baboon ductus from term, preterm, and glucocorticoid-treated preterm fetuses and found that both immature gestation and absence of antenatal glucocorticoid exposure decreased RNA expression of calcium- and potassium-channel genes involved in oxygen-induced constriction, and phosphodiesterase genes (that modulate cAMP/cGMP signaling). Ductus obtained from second trimester human pregnancies were genotyped for TFAP2B polymorphisms. When present, the rs2817399(A) allele also was associated with decreased expression of calcium- and potassium-channel genes. In contrast, alleles of two other TFAP2B polymorphisms, rs2817419(G) and rs2635727(T), which are not related to the incidence of PDA after birth, had no effect on RNA expression. In conclusion, three calcium- and potassium-channel genes (CACNA1G/ alpha1G, CACNB 2/CaL-beta2, and KCNA2/ Kv1.2) were similarly affected by each of the PDA risk factors. We speculate that these channels may play a significant role in closing the preterm ductus during prostaglandin inhibition and may be potential targets for future pharmacologic manipulations.
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Affiliation(s)
- Nahid Waleh
- Pharmaceutical Discovery Division, SRI International, Menlo Park, California 94025, USA
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Antonucci R, Bassareo P, Zaffanello M, Pusceddu M, Fanos V. Patent ductus arteriosus in the preterm infant: new insights into pathogenesis and clinical management. J Matern Fetal Neonatal Med 2010; 23 Suppl 3:34-7. [DOI: 10.3109/14767058.2010.509920] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rocha G, Ribeiro O, Guimarães H. Fluid and electrolyte balance during the first week of life and risk of bronchopulmonary dysplasia in the preterm neonate. Clinics (Sao Paulo) 2010; 65:663-74. [PMID: 20668623 PMCID: PMC2910854 DOI: 10.1590/s1807-59322010000700004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 04/06/2010] [Accepted: 04/06/2010] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Early fluid and electrolyte imbalances may be associated with an increased risk of bronchopulmonary dysplasia. OBJECTIVE We sought to establish an association between fluid and electrolyte balance in the first week of life and the risk of bronchopulmonary dysplasia. METHODS Clinical charts of 205 neonates <32 weeks gestational age and/or <1,250 g birth weight (admitted to our NICU between 1997 and 2008) were analyzed. Clinical features, fluid and electrolyte balance were analyzed for the first 7 days of life using multivariate models of generalized estimation equations. A p value <0.05 was considered significant in all of the hypothesis tests. RESULTS The prevalence of bronchopulmonary dysplasia was 22%. Lower gestational age and birth weight, male gender, less frequent use of antenatal steroids, respiratory distress syndrome, use of surfactant, patent ductus arteriosus, duration of invasive ventilation and NICU stay were significantly associated with bronchopulmonary dysplasia. The variation in serum values of potassium, phosphorus and creatinine during the first week of life also revealed an association with bronchopulmonary dysplasia. Higher mean plasma calcium values were associated with spontaneous closure of the patent ductus arteriosus. The use of indomethacin to induce patent ductus arteriosus closure was significantly higher in bronchopulmonary dysplasia patients. CONCLUSIONS Differences in renal function and tubular handling of potassium and phosphorus are present during the first week of life among preterm neonates who will develop bronchopulmonary dysplasia. The higher rate of patent ductus arteriosus and indomethacin use may influence these differences. Serum levels of calcium also appear to play a role in spontaneous ductus arteriosus closure.
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Affiliation(s)
- Gustavo Rocha
- Department of Pediatrics, Hospital de São João, Porto University, Portugal.
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25
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Abstract
A persistently patent ductus arteriosus (PDA) in preterm infants can have significant clinical consequences, particularly during the recovery period from respiratory distress syndrome. With improvement of ventilation and oxygenation, the pulmonary vascular resistance decreases early and rapidly, especially in very immature infants with extremely low birth weight (<1000 g). Subsequently, the left-to-right shunt through the ductus arteriosus (DA) is augmented, thereby increasing pulmonary blood flow, which leads to pulmonary edema and overall worsening of cardiopulmonary status. Prolonged ventilation, with the potential risks of volutrauma, barotrauma, and hyperoxygenation, is strongly associated with the development and severity of bronchopulmonary dysplasia/chronic lung disease. Substantial left-to-right shunting through the ductus may also increase the risk of intraventricular hemorrhage, necrotizing enterocolitis, and death. Postnatal ductal closure is regulated by exposure to oxygen and vasodilators; the ensuing vascular responses, mediated by potassium channels, voltage-gated calcium channels, mitochondrial-derived reactive oxygen species, and endothelin 1, depend on gestational age. Platelets are recruited to the luminal aspect of the DA during closure and probably promote thrombotic sealing of the constricted DA. Currently, it is unclear whether and when a conservative, pharmacologic, or surgical approach for PDA closure may be advantageous. Furthermore, it is unknown if prophylactic and/or symptomatic PDA therapy will cause substantive improvements in outcome. In this article we review the mechanisms underlying DA closure, risk factors and comorbidities of significant DA shunting, and current clinical evidence and areas of uncertainty in the diagnosis and treatment of PDA of the preterm infant.
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The role of ion channels in hypoxic pulmonary vasoconstriction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 661:3-14. [PMID: 20204720 DOI: 10.1007/978-1-60761-500-2_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hypoxic pulmonary vasoconstriction (HPV) is an important mechanism by which localized flow of blood in small resistance pulmonary arteries is matched to alveolar ventilation. This chapter discusses the role of several potassium and calcium channels in HPV, both in enhancing calcium influx into smooth muscle cells (SMCs) and in stimulating the release of calcium from the sarcoplasmic reticulum, thus increasing cytosolic calcium. The increase in calcium sensitivity caused by hypoxia is reviewed in Chapter 19. Particular attention is paid to the activity of the L-type calcium channels which increase calcium influx as a result of membrane depolarization and also increase calcium influx at any given membrane potential in response to hypoxia. In addition, activation of the L-type calcium channel may, in the absence of any calcium influx, cause calcium release from the sarcoplasmic reticulum. Many of these mechanisms have been reported to be involved in both HPV and in normoxic contraction of the ductus arteriosus.
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Akaike T, Jin MH, Yokoyama U, Izumi-Nakaseko H, Jiao Q, Iwasaki S, Iwamoto M, Nishimaki S, Sato M, Yokota S, Kamiya Y, Adachi-Akahane S, Ishikawa Y, Minamisawa S. T-type Ca2+ channels promote oxygenation-induced closure of the rat ductus arteriosus not only by vasoconstriction but also by neointima formation. J Biol Chem 2009; 284:24025-34. [PMID: 19567868 PMCID: PMC2781997 DOI: 10.1074/jbc.m109.017061] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 06/24/2009] [Indexed: 11/06/2022] Open
Abstract
The ductus arteriosus (DA), an essential vascular shunt for fetal circulation, begins to close immediately after birth. Although Ca(2+) influx through several membrane Ca(2+) channels is known to regulate vasoconstriction of the DA, the role of the T-type voltage-dependent Ca(2+) channel (VDCC) in DA closure remains unclear. Here we found that the expression of alpha1G, a T-type isoform that is known to exhibit a tissue-restricted expression pattern in the rat neonatal DA, was significantly up-regulated in oxygenated rat DA tissues and smooth muscle cells (SMCs). Immunohistological analysis revealed that alpha1G was localized predominantly in the central core of neonatal DA at birth. DA SMC migration was significantly increased by alpha1G overexpression. Moreover, it was decreased by adding alpha1G-specific small interfering RNAs or using R(-)-efonidipine, a highly selective T-type VDCC blocker. Furthermore, an oxygenation-mediated increase in an intracellular Ca(2+) concentration of DA SMCs was significantly decreased by adding alpha1G-specific siRNAs or using R(-)-efonidipine. Although a prostaglandin E receptor EP4 agonist potently promoted intimal thickening of the DA explants, R(-)-efonidipine (10(-6) m) significantly inhibited EP4-promoted intimal thickening by 40% using DA tissues at preterm in organ culture. Moreover, R(-)-efonidipine (10(-6) m) significantly attenuated oxygenation-induced vasoconstriction by approximately 27% using a vascular ring of fetal DA at term. Finally, R(-)-efonidipine significantly delayed the closure of in vivo DA in neonatal rats. These results indicate that T-type VDCC, especially alpha1G, which is predominantly expressed in neonatal DA, plays a unique role in DA closure, implying that T-type VDCC is an alternative therapeutic target to regulate the patency of DA.
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MESH Headings
- Animals
- Animals, Newborn
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, T-Type/metabolism
- Dihydropyridines/pharmacology
- Ductus Arteriosus/cytology
- Ductus Arteriosus/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Nitrophenols/pharmacology
- Organ Culture Techniques
- Organophosphorus Compounds/pharmacology
- Protein Isoforms/metabolism
- Rats
- Rats, Wistar
- Receptors, Prostaglandin E/antagonists & inhibitors
- Receptors, Prostaglandin E, EP4 Subtype
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
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Affiliation(s)
- Toru Akaike
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Mei-Hua Jin
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Utako Yokoyama
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Hiroko Izumi-Nakaseko
- the Department of Pharmacology, School of Medicine, Faculty of Medicine, Graduate School of Medical Sciences, Toho University, Toho 143-8540, Japan
| | - Qibin Jiao
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Shiho Iwasaki
- the Department of Pediatrics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Mari Iwamoto
- the Department of Pediatrics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Shigeru Nishimaki
- the Department of Pediatrics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Motohiko Sato
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Shumpei Yokota
- the Department of Pediatrics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Yoshinori Kamiya
- the Department of Anesthesiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Satomi Adachi-Akahane
- the Department of Pharmacology, School of Medicine, Faculty of Medicine, Graduate School of Medical Sciences, Toho University, Toho 143-8540, Japan
| | - Yoshihiro Ishikawa
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
- the Cardiovascular Research Institute, Departments of Cell Biology & Molecular Medicine and Medicine (Cardiology), New Jersey Medical School, Newark, New Jersey 07101-1709
| | - Susumu Minamisawa
- From the Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
- the Department of Life Science and Medical Bioscience, Waseda University, Tokyo 162-8480, Japan, and
- the Institute for Biomedical Engineering, Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo 162-8480, Japan
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28
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Reese J, Waleh N, Poole SD, Brown N, Roman C, Clyman RI. Chronic in utero cyclooxygenase inhibition alters PGE2-regulated ductus arteriosus contractile pathways and prevents postnatal closure. Pediatr Res 2009; 66:155-61. [PMID: 19390487 PMCID: PMC3066019 DOI: 10.1203/pdr.0b013e3181aa07eb] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although prostaglandin E2 (PGE2) vasodilates the ductus arteriosus, tocolysis with cyclooxygenase (COX) inhibitors delays postnatal ductus arteriosus closure. We used fetal mice and sheep to determine whether PGE2 has a role in the development of ductus contractility that is distinct from its function as a vasodilator. Prolonged exposure of fetal ductus to PGE2 in vitro increased the expression of CaL- and K+-channel genes (CaLalpha1c, CaLbeta2, Kir6.1, and Kv1.5, which regulate oxygen-induced constriction) without affecting the genes that regulate Rho-kinase-mediated calcium sensitization. Conversely, chronic exposure to COX inhibitors in utero decreased expression of CaL- and K+-channel genes, without affecting Rho-kinase-associated genes. Chronic COX inhibition in utero decreased the ductus' in vitro contractile response to stimuli that use CaL- and K+-channels (like O2 and K+), whereas the response to stimuli that act through Rho-kinase-mediated pathways (like U46619) was not significantly affected. Phosphodiesterase expression, which decreases the ductus' sensitivity to cAMP- or cGMP-dependent vasodilators, was increased by PGE2 exposure and decreased by COX inhibition, respectively. These studies identify potential downstream effectors of a PGE2-mediated, developmental program, regulating oxygen-induced ductus closure. Alterations in these effectors may explain the increased risk of patent ductus arteriosus (PDA) after in utero COX inhibition.
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Affiliation(s)
- Jeff Reese
- Department of Pediatrics, Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37232, USA
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29
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Cogolludo AL, Moral-Sanz J, van der Sterren S, Frazziano G, van Cleef ANH, Menéndez C, Zoer B, Moreno E, Roman A, Pérez-Vizcaino F, Villamor E. Maturation of O2 sensing and signaling in the chicken ductus arteriosus. Am J Physiol Lung Cell Mol Physiol 2009; 297:L619-30. [PMID: 19617310 DOI: 10.1152/ajplung.00092.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The increase in O(2) tension after birth is a major factor stimulating ductus arteriosus (DA) constriction and closure. Here we studied the role of the mitochondrial electron transport chain (ETC) as sensor, H(2)O(2) as mediator, and voltage-gated potassium (K(V)) channels and Rho kinase as effectors of O(2)-induced contraction in the chicken DA during fetal development. Switching from 0% to 21% O(2) contracted the pulmonary side of the mature DA (mature pDA) but had no effect in immature pDA and relaxed the aortic side of the mature DA (mature aDA). This contraction of the pDA was attenuated by inhibitors of the mitochondrial ETC and by the H(2)O(2) scavenger polyethylene glycol (PEG)-catalase. Moreover, O(2) increased reactive oxygen species (ROS) production, measured with the fluorescent probes dihydroethidium and 2',7'-dichlorofluorescein, only in mature pDA. The H(2)O(2) analog t-butyl-hydroperoxide mimicked the responses to O(2) in the three vessels. In contrast to immature pDA cells, mature pDA cells exhibited high-amplitude O(2)-sensitive potassium currents. The K(V) channel blocker 4-aminopyridine prevented the current inhibition elicited by O(2). The L-type Ca(2+) (Ca(L)) channel blocker nifedipine and the Rho kinase inhibitors Y-27632 and hydroxyfasudil induced a similar relaxation when mature pDA were stimulated with O(2) or H(2)O(2). Moreover, the sensitivity to these drugs increased with maturation. Our results indicate the presence of a common mechanism for O(2) sensing/signaling in mammalian and nonmammalian DA and favor the idea that, rather than a single mechanism, a parallel maturation of the sensor and effectors is critical for O(2) sensitivity appearance during development.
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Affiliation(s)
- Angel L Cogolludo
- Dept. of Pharmacology, School of Medicine, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain.
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30
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Waleh N, Reese J, Kajino H, Roman C, Seidner S, McCurnin D, Clyman RI. Oxygen-induced tension in the sheep ductus arteriosus: effects of gestation on potassium and calcium channel regulation. Pediatr Res 2009; 65:285-90. [PMID: 19092721 PMCID: PMC2692833 DOI: 10.1203/pdr.0b013e31819746a1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Compared with the full-term ductus arteriosus, the premature ductus is less likely to constrict when exposed to postnatal oxygen concentrations. We used isolated fetal sheep ductus arteriosus (pretreated with inhibitors of prostaglandin and nitric oxide production) to determine whether changes in K+ - and CaL-channel activity could account for the developmental differences in oxygen-induced tension. In the mature ductus, KV-channels appear to be the only K+-channels that oppose ductus tension. Oxygen concentrations between (2% and 15%) inhibit KV-channel activity, which increases the CaL-channel-mediated increase in tension. Low oxygen concentrations have a direct inhibitory effect on CaL-channel activity in the immature ductus; this is not the case in the mature ductus. In the immature ductus, three different K+-channel activities (KV, KCa, and KATP) oppose ductus tension and contribute to its decreased tone. Oxygen inhibits the activities of all three K+ -channels. The inhibitory effects of the three K+-channel activities decline with advancing gestation. The decline in K+ -channel activity is not due to decreased K+ -channel expression. Super-physiologic oxygen concentrations (>or=30% O2) constrict the ductus by using calcium-dependent pathways that are independent of K+- and CaL-channel activities. Super-physiologic oxygen concentrations eliminate the difference in tensions between the two age groups.
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Affiliation(s)
- Nahid Waleh
- Pharmaceutical Discovery Division, SRI International, Menlo Park, California 94025, USA
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31
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Weir EK, Obreztchikova M, Vargese A, Cabrera JA, Peterson DA, Hong Z. Mechanisms of oxygen sensing: a key to therapy of pulmonary hypertension and patent ductus arteriosus. Br J Pharmacol 2008; 155:300-7. [PMID: 18641675 PMCID: PMC2567893 DOI: 10.1038/bjp.2008.291] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Accepted: 06/23/2008] [Indexed: 11/08/2022] Open
Abstract
Specialized tissues that sense acute changes in the local oxygen tension include type 1 cells of the carotid body, neuroepithelial bodies in the lungs, and smooth muscle cells of the resistance pulmonary arteries and the ductus arteriosus (DA). Hypoxia inhibits outward potassium current in carotid body type 1 cells, leading to depolarization and calcium entry through L-type calcium channels. Increased intracellular calcium concentration ([Ca+ +]i) leads to exocytosis of neurotransmitters, thus stimulating the carotid sinus nerve and respiration. The same K+ channel inhibition occurs with hypoxia in pulmonary artery smooth muscle cells (PASMCs), causing contraction and providing part of the mechanism of hypoxic pulmonary vasoconstriction (HPV). In the SMCs of the DA, the mechanism works in reverse. It is the shift from hypoxia to normoxia that inhibits K+ channels and causes normoxic ductal contraction. In both PA and DA, the contraction is augmented by release of Ca+ + from the sarcoplasmic reticulum, entry of Ca+ + through store-operated channels (SOC) and by Ca+ + sensitization. The same three 'executive' mechanisms are partly responsible for idiopathic pulmonary arterial hypertension (IPAH). While vasoconstrictor mediators constrict both PA and DA and vasodilators dilate both vessels, only redox changes mimic oxygen by having directly opposite effects on the K+ channels, membrane potential, [Ca(++)]i and tone in the PA and DA. There are several different hypotheses as to how redox might alter tone, which remain to be resolved. However, understanding the mechanism will facilitate drug development for pulmonary hypertension and patent DA.
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Affiliation(s)
- E K Weir
- Department of Medicine, VA Medical Center and University of Minnesota, Minneapolis, MN 55417, USA.
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32
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Greyner H, Dzialowski EM. Mechanisms mediating the oxygen-induced vasoreactivity of the ductus arteriosus in the chicken embryo. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1647-59. [PMID: 18799631 DOI: 10.1152/ajpregu.00001.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The avian embryo provides a novel model for studying the ductus arteriosus (DA) during the transition from in ovo to ex ovo life. Here we examined the mechanisms regulating the vasoreactivity of the two morphologically distinct portions of the chicken DA (proximal and distal) in response to O(2). Oxygen-induced contraction is redox sensitive and reversed by the reducing agent dithiothreitol and the H(2)O(2) scavenger N-mercaptopropionylglycine. As in the mammalian DA, inhibiting mitochondrion-derived reactive oxygen species production with rotenone and antimycin A relaxed the O(2)-constricted DA. The contractile response to O(2) matures during hatching and is mimicked by the K(v) channel inhibitor 4-aminopyridine (4-AP) on day 19 and externally pipped (EP) embryos. Together, O(2) and 4-AP significantly increase DA tone above that observed with either alone. The O(2)-induced contraction is mediated by influx of extracellular Ca(2+) through l-type Ca(2+) and store-operated channels. Inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores play a minor role in the O(2)-induced contraction. The O(2)-induced contraction is mediated by the Rho kinase pathway, as fasudil and Y-27632 significantly relax the O(2) contracted DA. Prostaglandins E(2), F(2alpha), and D(2) produce significant contraction of the proximal DA. The O(2)-induced relaxation of the distal portion of the DA is mediated by an endothelial-derived nitric oxide/cGMP pathway. Both 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and endothelial cell removal inhibit O(2)-induced relaxation in the distal segment. Mechanisms regulating O(2)-induced contraction in chicken proximal DA are similar to those found in mammalian DA, making the chicken a useful model for studying development of this O(2)-sensitive vessel.
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Affiliation(s)
- Henry Greyner
- Department of Biological Science, University of North Texas, Denton, Texas 76203-5017, USA
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33
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34
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Thébaud B, Wu XC, Kajimoto H, Bonnet S, Hashimoto K, Michelakis ED, Archer SL. Developmental absence of the O2 sensitivity of L-type calcium channels in preterm ductus arteriosus smooth muscle cells impairs O2 constriction contributing to patent ductus arteriosus. Pediatr Res 2008; 63:176-81. [PMID: 18091358 DOI: 10.1203/pdr.0b013e31815ed059] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Patent ductus arteriosus (PDA) complicates the hospital course of premature infants. Impaired oxygen (O2)-induced vasoconstriction in preterm ductus arteriosus (DA) contributes to PDA and results, in part, from decreased function/expression of O2-sensitive, voltage-gated potassium channels (Kv) in DA smooth muscle cells (DASMCs). This paradigm suggests that activation of the voltage-sensitive L-type calcium channels (CaL), which increases cytosolic calcium ([Ca2+]i), is a passive consequence of membrane depolarization. However, effective Kv gene transfer only partially matures O2 responsiveness in preterm DA. Thus, we hypothesized that CaL are directly O2 sensitive and that immaturity of CaL function in preterm DA contributes to impaired O2 constriction. We show that preterm rabbit DA rings have reduced O2- and 4-aminopyridine (Kv blocker)-induced constriction. Preterm rabbit DASMCs have reduced O2-induced whole-cell calcium current (ICa) and [Ca2+]i. BAY K8644, a CaL activator, increased O2 constriction, ICa, and [Ca]i in preterm DASMCs to levels seen at term but had no effect on human and rabbit term DA. Preterm rabbit DAs have decreased gamma and increased alpha subunit protein expression. We conclude that the CaL in term rabbit and human DASMCs is directly O2 sensitive. Functional immaturity of CaL O2 sensitivity contributes to impaired O2 constriction in premature DA and can be reversed by BAY K8644.
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Affiliation(s)
- Bernard Thébaud
- Department of Pediatrics, Division of Neonatology, University of Alberta, Edmonton, T6G 2J3, AB, Canada
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35
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Alpha2delta1 dihydropyridine receptor subunit is a critical element for excitation-coupled calcium entry but not for formation of tetrads in skeletal myotubes. Biophys J 2008; 94:3023-34. [PMID: 18192372 DOI: 10.1529/biophysj.107.118893] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been shown that small interfering RNA (siRNA) partial knockdown of the alpha(2)delta(1) dihydropyridine receptor subunits cause a significant increase in the rate of activation of the L-type Ca(2+) current in myotubes but have little or no effect on skeletal excitation-contraction coupling. This study used permanent siRNA knockdown of alpha(2)delta(1) to address two important unaddressed questions. First, does the alpha(2)delta(1) subunit contribute to the size and/or spacing of tetradic particles? Second, is the alpha(2)delta(1) subunit important for excitation-coupled calcium entry? We found that the size and spacing of tetradic particles is unaffected by siRNA knockdown of alpha(2)delta(1), indicating that the visible particle represents the alpha(1s) subunit. Strikingly, >97% knockdown of alpha(2)delta(1) leads to a complete loss of excitation-coupled calcium entry during KCl depolarization and a more rapid decay of Ca(2+) transients during bouts of repetitive electrical stimulation like those occurring during normal muscle activation in vivo. Thus, we conclude that the alpha(2)delta(1) dihydropyridine receptor subunit is physiologically necessary for sustaining Ca(2+) transients in response to prolonged depolarization or repeated trains of action potentials.
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Clyman RI, Waleh N, Kajino H, Roman C, Mauray F. Calcium-dependent and calcium-sensitizing pathways in the mature and immature ductus arteriosus. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1650-6. [PMID: 17652360 DOI: 10.1152/ajpregu.00300.2007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies performed in sheep and baboons have shown that after birth, the normoxic muscle media of ductus arteriosus (DA) becomes profoundly hypoxic as it constricts and undergoes anatomic remodeling. We used isolated fetal lamb DA (pretreated with inhibitors of prostaglandin and nitric oxide production) to determine why the immature DA fails to remain tightly constricted during the hypoxic phase of remodeling. Under normoxic conditions, mature DA constricts to 70% of its maximal active tension (MAT). Half of its normoxic tension is due to Ca(2+) entry through calcium L-channels and store-operated calcium (SOC) channels. The other half is independent of extracellular Ca(2+) and is unaffected by inhibitors of sarcoplasmic reticulum (SR) Ca(2+) release (ryanodine) or reuptake [cyclopiazonic acid (CPA)]. The mature DA relaxes slightly during hypoxia (to 60% MAT) due to decreases in calcium L-channel-mediated Ca(2+) entry. Inhibitors of Rho kinase and tyrosine kinase inhibit both Ca(2+)-dependent and Ca(2+)-independent DA tension. Although Rho kinase activity may increase during gestation, immature DA develop lower tensions than mature DA, primarily because of differences in the way they process Ca(2+). Calcium L-channel expression increases with advancing gestation. Under normoxic conditions, differences in calcium L-channel-mediated Ca(2+) entry account for differences in tension between immature (60% MAT) and mature (70% MAT) DA. Under hypoxic conditions, differences in both calcium L-channel-dependent and calcium L-channel-independent Ca(2+) entry, account for differences in tension between immature (33% MAT) and mature (60% MAT) DA. Stimulation of Ca(2+) entry through reverse-mode Na(+)/Ca(2+) exchange or CPA-induced SOC channel activity constrict the DA and eliminate differences between immature and mature DA during both hypoxia and normoxia.
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Affiliation(s)
- Ronald I Clyman
- Cardiovascular Research Institute and Department of Pediatrics, University of California, San Francisco, 513 Parnassus Ave., Rm. 1408 HSW, UCSF Box 0544, San Francisco, CA 94143-0544, USA.
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37
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Kajimoto H, Hashimoto K, Bonnet SN, Haromy A, Harry G, Moudgil R, Nakanishi T, Rebeyka I, Thébaud B, Michelakis ED, Archer SL. Oxygen activates the Rho/Rho-kinase pathway and induces RhoB and ROCK-1 expression in human and rabbit ductus arteriosus by increasing mitochondria-derived reactive oxygen species: a newly recognized mechanism for sustaining ductal constriction. Circulation 2007; 115:1777-88. [PMID: 17353442 DOI: 10.1161/circulationaha.106.649566] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Constriction of the ductus arteriosus (DA) is initiated at birth by inhibition of O2-sensitive K+ channels in DA smooth muscle cells. Subsequent membrane depolarization and calcium influx through L-type calcium channels initiates functional closure. We hypothesize that Rho-kinase activation is an additional mechanism that sustains DA constriction. METHODS AND RESULTS The effect of increased PO2 on the activity and expression of Rho-kinase was assessed in DAs from neonates with hypoplastic left-heart syndrome (n=15) and rabbits (339 term and 99 preterm rabbits). Rho-kinase inhibitors (Y-27632 and fasudil) prevent and reverse O2 constriction. Heterogeneity exists in the sensitivity of constrictors (PO2=endothelin=phenylephrine>KCl) and of fetal vessels (DA=pulmonary artery>aorta) to Rho-kinase inhibition. Inhibition of L-type calcium channels (nifedipine) or removal of extracellular calcium inhibits approximately two thirds of O2 constriction. Residual DA constriction reflects calcium sensitization, which persists after removal of extracellular calcium and blocking of sarcoplasmic reticulum Ca2+-ATPase. In term DA, an increase in PO2 activates Rho-kinase and thereby increases RhoB and ROCK-1 expression. Activation of Rho-kinase in DA smooth muscle cells is initiated by a PO2-dependent, rotenone-sensitive increase in mitochondrion-derived reactive O2 species. O2 effects on Rho-kinase are mimicked by exogenous H2O2. In preterm DAs, immaturity of mitochondrial reactive oxygen species generation is associated with reduced and delayed O2 constriction and lack of PO2-dependent upregulation of Rho-kinase expression. CONCLUSIONS O2 activates Rho-kinase and increases Rho-kinase expression in term DA smooth muscle cells by a redox-regulated, positive-feedback mechanism that promotes sustained vasoconstriction. Conversely, Rho-kinase inhibitors may be useful in maintaining DA patency, as a bridge to congenital heart surgery.
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Affiliation(s)
- Hidemi Kajimoto
- Vascular Biology Group, Alberta Cardiovascular and Stroke Research Centre (ABACUS), University of Alberta, Edmonton, Canada
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