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Miedema M, McCall KE, Perkins EJ, Oakley RB, Pereira-Fantini PM, Rajapaksa AE, Waldmann AD, Tingay DG, van Kaam AH. Lung Recruitment Strategies During High Frequency Oscillatory Ventilation in Preterm Lambs. Front Pediatr 2018; 6:436. [PMID: 30723711 PMCID: PMC6349831 DOI: 10.3389/fped.2018.00436] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/31/2018] [Indexed: 01/28/2023] Open
Abstract
Background: High frequency oscillatory ventilation (HFOV) is considered a lung protective ventilation mode in preterm infants only if lung volume is optimized. However, whilst a "high lung volume strategy" is advocated for HFOV in preterm infants this strategy is not precisely defined. It is not known to what extent lung recruitment should be pursued to provide lung protection. In this study we aimed to determine the relationship between the magnitude of lung volume optimization and its effect on gas exchange and lung injury in preterm lambs. Methods: 36 surfactant-deficient 124-127 d lambs commenced HFOV immediately following a sustained inflation at birth and were allocated to either (1) no recruitment (low lung volume; LLV), (2) medium- (MLV), or (3) high lung volume (HLV) recruitment strategy. Gas exchange and lung volume changes over time were measured. Lung injury was analyzed by post mortem pressure-volume curves, alveolar protein leakage, gene expression, and histological injury score. Results: More animals in the LLV developed a pneumothorax compared to both recruitment groups. Gas exchange was superior in both recruitment groups compared to LLV. Total lung capacity tended to be lower in the LLV group. Other parameters of lung injury were not different. Conclusions: Lung recruitment during HFOV optimizes gas exchange but has only modest effects on lung injury in a preterm animal model. In the HLV group aiming at a more extensive lung recruitment gas exchange was better without affecting lung injury.
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Affiliation(s)
- Martijn Miedema
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Neonatology, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Karen E McCall
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Regina B Oakley
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | | | - Anushi E Rajapaksa
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Neonatology, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | | | - David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Neonatology, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Anton H van Kaam
- Department of Neonatology, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Tingay DG, Rajapaksa A, McCall K, Zonneveld CEE, Black D, Perkins E, Sourial M, Lavizzari A, Davis PG. The interrelationship of recruitment maneuver at birth, antenatal steroids, and exogenous surfactant on compliance and oxygenation in preterm lambs. Pediatr Res 2016; 79:916-21. [PMID: 26866905 DOI: 10.1038/pr.2016.25] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/07/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND To describe the interrelationship between antenatal steroids, exogenous surfactant, and two approaches to lung recruitment at birth on oxygenation and respiratory system compliance (Cdyn) in preterm lambs. METHODS Lambs (n = 63; gestational age 127 ± 1 d) received either surfactant at 10-min life (Surfactant), antenatal corticosteroids (Steroid), or neither (Control). Within each epoch lambs were randomly assigned to a 30-s 40 cmH2O sustained inflation (SI) or an initial stepwise positive end-expiratory pressure (PEEP) open lung ventilation (OLV) maneuver at birth. All lambs then received the same management for 60-min with alveolar-arterial oxygen difference (AaDO2) and Cdyn measured at regular time points. RESULTS Overall, the OLV strategy improved Cdyn and AaDO2 (all epochs except Surfactant) compared to SI (all P < 0.05; two-way ANOVA). Irrespective of strategy, Cdyn was better in the Steroid group in the first 10 min (all P < 0.05). Thereafter, Cdyn was similar to Steroid epoch in the OLV + Surfactant, but not SI + Surfactant group. OLV influenced the effect of steroid and surfactant (P = 0.005) on AaDO2 more than SI (P = 0.235). CONCLUSIONS The antenatal state of the lung influences the type and impact of a recruitment maneuver at birth. The effectiveness of surfactant maybe enhanced using PEEP-based time-dependent recruitment strategies rather than approaches solely aimed at initial lung liquid clearance.
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Affiliation(s)
- David G Tingay
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.,Department of Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia.,Neonatal Research Group, The Royal Women's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Anushi Rajapaksa
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Karen McCall
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Cornelis E E Zonneveld
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Don Black
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Elizabeth Perkins
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Magdy Sourial
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.,Department of Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Anna Lavizzari
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.,NICU, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico-Università degli Studi di Milano, Milano, Italy
| | - Peter G Davis
- Neonatal Research Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.,Neonatal Research Group, The Royal Women's Hospital, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Victoria, Australia
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Tingay DG, Rajapaksa A, Zonneveld CE, Black D, Perkins EJ, Adler A, Grychtol B, Lavizzari A, Frerichs I, Zahra VA, Davis PG. Spatiotemporal Aeration and Lung Injury Patterns Are Influenced by the First Inflation Strategy at Birth. Am J Respir Cell Mol Biol 2016; 54:263-72. [DOI: 10.1165/rcmb.2015-0127oc] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Tingay DG, Lavizzari A, Zonneveld CEE, Rajapaksa A, Zannin E, Perkins E, Black D, Sourial M, Dellacà RL, Mosca F, Adler A, Grychtol B, Frerichs I, Davis PG. An individualized approach to sustained inflation duration at birth improves outcomes in newborn preterm lambs. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1138-49. [DOI: 10.1152/ajplung.00277.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/17/2015] [Indexed: 01/18/2023] Open
Abstract
A sustained first inflation (SI) at birth may aid lung liquid clearance and aeration, but the impact of SI duration relative to the volume-response of the lung is poorly understood. We compared three SI strategies: 1) variable duration defined by attaining volume equilibrium using real-time electrical impedance tomography (EIT; SIplat); 2) 30 s beyond equilibrium (SIlong); 3) short 30-s SI (SI30); and 4) positive pressure ventilation without SI (no-SI) on spatiotemporal aeration and ventilation (EIT), gas exchange, lung mechanics, and regional early markers of injury in preterm lambs. Fifty-nine fetal-instrumented lambs were ventilated for 60 min after applying the allocated first inflation strategy. At study completion molecular and histological markers of lung injury were analyzed. The time to SI volume equilibrium, and resultant volume, were highly variable; mean (SD) 55 (34) s, coefficient of variability 59%. SIplat and SIlong resulted in better lung mechanics, gas exchange and lower ventilator settings than both no-SI and SI30. At 60 min, alveolar-arterial difference in oxygen was a mean (95% confidence interval) 130 (13, 249) higher in SI30 vs. SIlong group (two-way ANOVA). These differences were due to better spatiotemporal aeration and tidal ventilation, although all groups showed redistribution of aeration towards the nondependent lung by 60 min. Histological lung injury scores mirrored spatiotemporal change in aeration and were greatest in SI30 group ( P < 0.01, Kruskal-Wallis test). An individualized volume-response approach to SI was effective in optimizing aeration, homogeneous tidal ventilation, and respiratory outcomes, while an inadequate SI duration had no benefit over positive pressure ventilation alone.
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Affiliation(s)
- David G. Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatology, The Royal Children's Hospital, Parkville, Australia
- Neonatal Research, The Royal Women's Hospital, Parkville, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Anna Lavizzari
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatal Intensive Care Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico-Università Degli Studi di Milano, Milano, Italy
| | | | - Anushi Rajapaksa
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Emanuela Zannin
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Ingegneria Biomedica-DEIB, Politecnico di Milano University, Milano, Italy
| | - Elizabeth Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Don Black
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Magdy Sourial
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Raffaele L. Dellacà
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Ingegneria Biomedica-DEIB, Politecnico di Milano University, Milano, Italy
| | - Fabio Mosca
- Neonatal Intensive Care Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico-Università Degli Studi di Milano, Milano, Italy
| | - Andy Adler
- Systems and Computer Engineering, Carleton University, Ottawa, Canada
| | - Bartłomiej Grychtol
- Fraunhofer Project Group for Automation in Medicine and Biotechnology, Mannheim, Germany
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany; and
| | - Peter G. Davis
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatal Research, The Royal Women's Hospital, Parkville, Australia
- Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia
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5
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Tingay DG, Polglase GR, Bhatia R, Berry CA, Kopotic RJ, Kopotic CP, Song Y, Szyld E, Jobe AH, Pillow JJ. Pressure-limited sustained inflation vs. gradual tidal inflations for resuscitation in preterm lambs. J Appl Physiol (1985) 2015; 118:890-7. [PMID: 25635005 DOI: 10.1152/japplphysiol.00985.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/26/2015] [Indexed: 01/09/2023] Open
Abstract
Support of the mechanically complex preterm lung needs to facilitate aeration while avoiding ventilation heterogeneities: whether to achieve this gradually or quickly remains unclear. We compared the effect of gradual vs. constant tidal inflations and a pressure-limited sustained inflation (SI) at birth on gas exchange, lung mechanics, gravity-dependent lung volume distribution, and lung injury in 131-day gestation preterm lambs. Lambs were resuscitated with either 1) a 20-s, 40-cmH2O pressure-limited SI (PressSI), 2) a gradual increase in tidal volume (Vt) over 5-min from 3 ml/kg to 7 ml/kg (IncrVt), or 3) 7 ml/kg Vt from birth. All lambs were subsequently ventilated for 15 min with 7 ml/kg Vt with the same end-expiratory pressure. Lung mechanics, gas exchange and spatial distribution of end-expiratory volume (EEV), and tidal ventilation (electrical impedance tomography) were recorded regularly. At 15 min, early mRNA tissue markers of lung injury were assessed. The IncrVt group resulted in greater tissue hysteresivity at 5 min (P = 0.017; two-way ANOVA), higher alveolar-arterial oxygen difference from 10 min (P < 0.01), and least uniform gravity-dependent distribution of EEV. There were no other differences in lung mechanics between groups, and the PressSI and 7 ml/kg Vt groups behaved similarly throughout. EEV was more uniformly distributed, but Vt least so, in the PressSI group. There were no differences in mRNA markers of lung injury. A gradual increase in Vt from birth resulted in less recruitment of the gravity-dependent lung with worse oxygenation. There was no benefit of a SI at birth over mechanical ventilation with 7 ml/kg Vt.
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Affiliation(s)
- David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia; Neonatal Research, The Royal Women's Hospital, Melbourne, Victoria, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Clayton, Victoria, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Risha Bhatia
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia; Neonatal Research, The Royal Women's Hospital, Melbourne, Victoria, Australia
| | - Clare A Berry
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia
| | | | | | - Yong Song
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Edgardo Szyld
- Universidad Abierta Interamericana (UAI), Buenos Aires, Argentina; Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Alan H Jobe
- Cincinnati Children's Hospital Medical Centre, Cincinnati, Ohio
| | - J Jane Pillow
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia;
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Bronchopulmonary dysplasia: a review. Arch Gynecol Obstet 2013; 288:325-33. [DOI: 10.1007/s00404-013-2753-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 02/04/2013] [Indexed: 10/27/2022]
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Wolfson MR, Wu J, Hubert TL, Gregory TJ, Mazela J, Shaffer TH. Lucinactant attenuates pulmonary inflammatory response, preserves lung structure, and improves physiologic outcomes in a preterm lamb model of RDS. Pediatr Res 2012; 72:375-83. [PMID: 22821059 PMCID: PMC3888789 DOI: 10.1038/pr.2012.96] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Acute inflammatory responses to supplemental oxygen and mechanical ventilation have been implicated in the pathophysiological sequelae of respiratory distress syndrome (RDS). Although surfactant replacement therapy (SRT) has contributed to lung stability, the effect on lung inflammation is inconclusive. Lucinactant contains sinapultide (KL4), a novel synthetic peptide that functionally mimics surfactant protein B, a protein with anti-inflammatory properties. We tested the hypothesis that lucinactant may modulate lung inflammatory response to mechanical ventilation in the management of RDS and may confer greater protection than animal-derived surfactants. METHODS Preterm lambs (126.8 ± 0.2 SD d gestation) were randomized to receive lucinactant, poractant alfa, beractant, or no surfactant and studied for 4 h. Gas exchange and pulmonary function were assessed serially. Lung inflammation biomarkers and lung histology were assessed at termination. RESULTS SRT improved lung compliance relative to no SRT without significant difference between SRT groups. Lucinactant attenuated lung and systemic inflammatory response, supported oxygenation at lower ventilatory requirements, and preserved lung structural integrity to a greater degree than either no SRT or SRT with poractant alfa or beractant. CONCLUSION These data suggest that early intervention with lucinactant may more effectively mitigate pulmonary pathophysiological sequelae of RDS than the animal-derived surfactants poractant alfa or beractant.
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Affiliation(s)
- Marla R. Wolfson
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania,Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania,Departments of Pediatrics, Temple University School of Medicine, Philadelphia, Pennsylvania,Center for Inflammation, Translational, and Clinical Lung Research, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Jichuan Wu
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania,Center for Inflammation, Translational, and Clinical Lung Research, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Terrence L. Hubert
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania
| | | | - Jan Mazela
- Discovery Laboratories, Inc., Warrington, Pennsylvania,Poznan University of Medical Sciences, Poznan, Poland
| | - Thomas H. Shaffer
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania,Departments of Pediatrics, Temple University School of Medicine, Philadelphia, Pennsylvania,Center For Pediatric Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware
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Rahmel D, Pohlmann G, Iwatschenko P, Volland J, Liebisch S, Kock H, Mecklenburg L, Maurer C, Kemkowski J, Taut F. The non-intubated, spontaneously breathing, continuous positive airway pressure (CPAP) ventilated pre-term lamb: A unique animal model. Reprod Toxicol 2012; 34:204-15. [DOI: 10.1016/j.reprotox.2012.05.089] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 05/18/2012] [Accepted: 05/21/2012] [Indexed: 11/25/2022]
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Pregnancy and Outcome of Uterine Allotransplantation and Assisted Reproduction in Sheep. J Minim Invasive Gynecol 2011; 18:238-45. [DOI: 10.1016/j.jmig.2010.11.006] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 11/15/2010] [Accepted: 11/18/2010] [Indexed: 11/23/2022]
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von Bismarck P, Klemm K, Wistädt CFG, Winoto-Morbach S, Uhlig U, Schütze S, Uhlig S, Lachmann B, Krause MF. Surfactant “fortification” by topical inhibition of nuclear factor-κB activity in a newborn piglet lavage model*. Crit Care Med 2007; 35:2309-18. [DOI: 10.1097/01.ccm.0000281472.47067.45] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lazic T, Wyatt TA, Matic M, Meyerholz DK, Grubor B, Gallup JM, Kersting KW, Imerman PM, Almeida-De-Macedo M, Ackermann MR. Maternal alcohol ingestion reduces surfactant protein A expression by preterm fetal lung epithelia. Alcohol 2007; 41:347-55. [PMID: 17889311 PMCID: PMC2083706 DOI: 10.1016/j.alcohol.2007.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 07/19/2007] [Accepted: 07/19/2007] [Indexed: 12/31/2022]
Abstract
In addition to neurodevelopmental effects, alcohol consumption at high levels during pregnancy is associated with immunomodulation and premature birth. Premature birth, in turn, is associated with increased susceptibility to various infectious agents such as respiratory syncytial virus (RSV). The initial line of pulmonary innate defense includes the mucociliary apparatus, which expels microorganisms trapped within the airway secretions. Surfactant proteins A and D (SP-A and SP-D, respectively) are additional components of pulmonary innate immunity and have an important role in pulmonary defense against inhaled pathogens. The purpose of this study was to determine if chronic alcohol consumption during the third trimester of pregnancy alters the function of the mucociliary apparatus and expression of SP-A and SP-D of fetal lung epithelia. Sixteen, date-mated ewes were assigned to two different groups; an ethanol-exposed group in which ewes received ethanol through surgically implanted intra-abomasal cannula during the third trimester of pregnancy, and a control group in which ewes received the equivalent amount of water instead of ethanol. Within these two groups, ewes were further randomly assigned to a full-term group in which the lambs were naturally delivered, and a preterm group in which the lambs were delivered prematurely via an abdominal incision and uterotomy. Ethanol was administered five times a week as a 40% solution at 1g/kg of body weight. The mean maternal serum alcohol concentration measured 6h postadministration was 16.3+/-4.36 mg/dl. Tracheas from six full-term lambs were collected to assess ciliary beat frequency (CBF). The lung tissue from all (24) lambs was collected for immunohistochemistry analysis of SP-A and SP-D protein production and fluorogenic real-time quantitative polymerase chain reaction analysis of SP-A and SP-D mRNA levels. Exposure to ethanol during pregnancy significantly blocked stimulated increase in CBF through ethanol-mediated desensitization of cAMP-dependent protein kinase. In addition, preterm born/ethanol-exposed lambs showed significantly decreased SP-A mRNA expression when compared with the preterm born/control group (P=.004); no significant changes were seen with SP-D. The full-term/ethanol-exposed lambs had no significant alterations in mRNA levels, but had significantly less detectable SP-A protein when compared with the full-term/control lambs (P=.02). These findings suggest that chronic maternal ethanol consumption during the third trimester of pregnancy alters innate immune gene expression in fetal lung. These alterations may underlie increased susceptibility of preterm infants, exposed to ethanol in utero, to RSV and other microbial agents.
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Affiliation(s)
- Tatjana Lazic
- Department of Veterinary Pathology, 2740 College of Veterinary Medicine, Iowa State University, Ames, IA 50011-1250, USA.
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Hillman NH, Moss TJM, Kallapur SG, Bachurski C, Pillow JJ, Polglase GR, Nitsos I, Kramer BW, Jobe AH. Brief, large tidal volume ventilation initiates lung injury and a systemic response in fetal sheep. Am J Respir Crit Care Med 2007; 176:575-81. [PMID: 17641159 PMCID: PMC1994225 DOI: 10.1164/rccm.200701-051oc] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Premature infants are exposed to potentially injurious ventilation in the delivery room. Assessments of lung injury are confounded by effects of subsequent ventilatory support. OBJECTIVES To evaluate the injury response to a brief period of large tidal volume (Vt) ventilation, simulating neonatal resuscitation in preterm neonates. METHODS Preterm lambs (129 d gestation; term is150 d) were ventilated (Vt = 15 ml/kg, no positive end-expiratory pressure) for 15 minutes to simulate delivery room resuscitation, either with the placental circulation intact (fetal resuscitation [ FR]) or after delivery (neonatal resuscitation [NR]). After the initial 15 minutes, lambs received surfactant and were maintained with either ventilatory support (FR-VS and NR-VS) or placental support (FR-PS) for 2 hours, 45 minutes. A control group received no resuscitation and was maintained with placental support. Samples of bronchoalveolar lavage fluid, lung, and liver were analyzed. MEASUREMENTS AND MAIN RESULTS Inflammatory cells and protein in bronchoalveolar lavage fluid, heat shock protein-70 immunostaining, IL-1beta, IL-6, IL-8, monocyte chemotactic protein-1, serum amyloid A (SAA)-3, Toll-like receptor (TLR)-2, and TLR4 mRNA in the lungs were increased in the FR-PS group compared with control animals. There were further elevations in neutrophils, IL-6, and IL-8 mRNA in the FR-VS and NR-VS groups compared with FR-PS. SAA3, TLR2, and TLR4 mRNA increased in the liver in all resuscitation groups relative to control animals. CONCLUSIONS Ventilation for 15 minutes with a Vt of 15 ml/kg initiates an injurious process in the preterm lung and a hepatic acute-phase response. Subsequent ventilatory support causes further increases in some injury indicators.
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Affiliation(s)
- Noah H Hillman
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA
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Proquitté H, Dushe T, Hammer H, Rüdiger M, Schmalisch G, Wauer RR. Observational study to compare the clinical efficacy of the natural surfactants Alveofact and Curosurf in the treatment of respiratory distress syndrome in premature infants. Respir Med 2007; 101:169-76. [PMID: 16698258 DOI: 10.1016/j.rmed.2006.03.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 03/23/2006] [Accepted: 03/25/2006] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Natural surfactants have been shown to be superior to synthetic surfactants in the treatment of neonatal respiratory distress syndrome (RDS). In Germany, Alveofact (A) and Curosurf (C) are the most frequently used natural surfactant preparations. The aim of this retrospective, observational study was to compare the effects of A and C on gas exchange and outcome in premature infants. METHODS During a 5-year period in our neonatal intensive care unit (NICU), 187 premature infants were treated with surfactant, with 82 receiving A and 105 receiving C. We recorded F(I)O(2) and gas exchange (PaO(2)/F(I)O(2) ratio, PaCO(2), SaO(2)) during the first 72h after surfactant application and the incidence of outcome parameters at day 28 (bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH grade III or IV), patent ductus arteriosus (PDA), pneumothorax, necrotizing enterocolites (NEC) and death). The differences between the patient groups were assessed by ANOVA or the calculation of relative risks. Bonferroni correction was used for multiple comparisons. RESULTS There were no statistically significant differences between infants treated with A and C in mean gestational age (28.4 vs. 28.4 weeks), birth weight (1210 vs.1258 g) and time of first surfactant application (60 vs. 90 min postnatal). We observed no significant between group differences in course of F(I)O(2) and blood gases, or in incidence at day 28 of BPD (41.7% vs. 42.8%), IVH III/IV (18.3% vs. 14.3%), pneumothorax (9.8% vs. 4.8%), PDA (23.2% vs. 21.9%), PVL (7.3% vs. 9.5%) and death (17% vs. 17.1%). There were also no statistically significant differences in the subgroup of infants <28 weeks. The lower incidence of NEC in A compared with C (1.2% vs. 10.5%, P=0.01) was not statistically significant after Bonferroni correction. CONCLUSION Independent of gestational age no significant difference in the clinical efficacy of A and C was observed.
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Affiliation(s)
- Hans Proquitté
- Clinic of Neonatology (Charité Campus Mitte), Humboldt-University Berlin, Berlin.
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Kawashima K, Meyerholz DK, Gallup JM, Grubor B, Lazic T, Lehmkuhl HD, Ackermann MR. Differential expression of ovine innate immune genes by preterm and neonatal lung epithelia infected with respiratory syncytial virus. Viral Immunol 2006; 19:316-23. [PMID: 16817774 PMCID: PMC2791066 DOI: 10.1089/vim.2006.19.316] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Preterm infants have increased susceptibility to severe manifestations of respiratory syncytial virus (RSV) infection. The cause(s) for this age-dependent vulnerability is/are not well-defined, but alterations in innate immune products have been implicated. In sheep, RSV disease severity has similar age-dependent characteristics and sheep have several related innate molecules for study during pulmonary infection including surfactant protein A (SP-A), surfactant protein D (SP-D), sheep beta defensin 1 (SBD1), monocyte chemotactic protein 1 (MCP1), and Toll-like receptor 4 (TLR4). However, the in vivo cellular gene expression as a response to RSV infection is poorly understood. In this study, the effect of RSV infection on expression of these innate immune genes was determined for bovine RSV-infected (bRSV+ fluorescence) epithelial cells, adjacent cells lacking bRSV antigen (adjoining cells lacking fluorescence), and control cells from non-infected lung using laser capture microdissection (LCM) and real-time RT-PCR. Control lambs had increased expression of innate immune molecules in full term (term) compared to preterm epithelia with statistical significance in SBD1, SP-D, and TLR4 mRNA. Infected cells (bRSV+ fluorescent cells) had consistently higher mRNA levels of SP-A (preterm and term), MCP1 (preterm and term), and SP-D (preterm). Interestingly, bRSV- cells of infected term lambs had significantly reduced SP-D mRNA expression compared to bRSV+ and control epithelia, suggesting that RSV infected cells may regulate the adjacent epithelial SP-D expression. This study defines specific innate immune components (e.g., SBD1, SP-D, and TLR4) that have differential age-dependent expression in the airway epithelia. Furthermore, cellular bRSV infection enhanced certain innate immune components while suppressing adjacent cellular SP-D expression in term animals. These in vivo gene expression results provide a framework for future studies on age-dependent susceptibility to RSV and RSV pathogenesis.
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Affiliation(s)
- Kenji Kawashima
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University Ames, Iowa 50011-1250, USA
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15
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Meyerholz DK, DeGraaff JA, Gallup JM, Olivier AK, Ackermann MR. Depletion of alveolar glycogen corresponds with immunohistochemical development of CD208 antigen expression in perinatal lamb lung. J Histochem Cytochem 2006; 54:1247-53. [PMID: 16899762 PMCID: PMC2791090 DOI: 10.1369/jhc.6a7002.2006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CD208 DC lysosomal-associated protein is a marker of activated human dendritic cells; however, recently it was described as a marker of adult type II pneumocytes in many species including humans and sheep. Our hypothesis was that CD208 is developmentally regulated in lung pneumocytes. Lamb lungs at varying stages of development were stained immunohistochemically for CD208 and with Nile red (a fluorescent stain for lamellar bodies of type II cells) along with pulmonary markers of maturation (glycogen stores and surfactant protein A [SP-A] expression) or proliferation (Ki-67). CD208 staining and Nile red were localized to rare pneumocytes in young fetal lambs (day 115), increasing in frequency and stain intensity with age. Periodic acid-Schiff staining of glycogen granules was most prominent in the young lambs (day 115) with reduced staining through advancing lung development. SP-A was detected in pulmonary epithelia and staining in alveoli increased through gestation with decreased staining at 2 weeks of age. Intranuclear Ki-67 staining decreased through late gestation but was increased in 2-week-old lambs. Ontogeny of CD208 staining and depletion of glycogen were correlated (p<0.0001) and consistent with the premise that CD208 is localized to developing lamellar bodies. The findings suggest that CD208 antigen expression may serve as a marker for pneumocyte maturation in the developing fetal lung.
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Affiliation(s)
- David K Meyerholz
- DVM, DACVP Professor and J.G. Salsbury Endowed Chair, Department of Veterinary Pathology, 2738 Veterinary Medicine, Iowa State University, Ames, IA 50011-1250, USA
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16
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Turunen R, Nupponen I, Siitonen S, Repo H, Andersson S. Onset of mechanical ventilation is associated with rapid activation of circulating phagocytes in preterm infants. Pediatrics 2006; 117:448-54. [PMID: 16452365 DOI: 10.1542/peds.2005-0123] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE In preterm infants with respiratory distress syndrome (RDS), circulating neutrophils are activated. Kinetics and effects of surfactant therapy on this activation are unknown. Therefore, we studied activation of circulating neutrophils and monocytes in newborn preterm infants with and without RDS. PATIENTS AND METHODS Preterm infants with RDS who were mechanically ventilated and received surfactant ("ventilated infants": n = 38; mean gestational age +/- SD: 28.3 +/- 2.2 weeks; mean birth weight +/- SD: 1086 +/- 353 g) and preterm infants who received nasal continuous positive airway pressure (n = 8) or no ventilatory support (n = 17) ("control infants": mean gestational age +/- SD: 32.1 +/- 1.2 weeks; mean birth weight +/- SD: 1787 +/- 457 g) were recruited. Blood samples were taken from ventilated infants at birth, before surfactant treatment, at 1 and 2 hours after surfactant, and at 12 to 24 hours of age. Blood samples were taken from control infants at birth, at 2 to 6 hours, and at 12 to 24 hours of age. Phagocyte CD11b expression was analyzed by flow cytometry. RESULTS In ventilated infants, phagocyte CD11b expression increased from birth to the first postnatal samples. It increased further by 12 to 24 hours of age. Control infants with or without nasal continuous positive airway pressure showed no significant increase after birth. At 12 to 24 hours of age, phagocyte CD11b expression was higher in ventilated infants than in control infants. In ventilated infants, neutrophil CD11b expression at 1 and 2 hours after surfactant correlated positively with gestational age. CONCLUSIONS In preterm infants with RDS, significant activation of circulating phagocytes occurs within 1 to 3 hours of the onset of mechanical ventilation, independent of surfactant administration, which indicates that mechanical ventilation may be the inducer of this systemic inflammatory response.
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Affiliation(s)
- Riikka Turunen
- Hospital for Children and Adolescents, Helsinki, Finland.
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17
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Gastiasoro-Cuesta E, Alvarez-Diaz FJ, Rey-Santano C, Arnaiz-Renedo A, Loureiro-Gonzalez B, Valls-i-Soler A. Acute and sustained effects of lucinactant versus poractant-alpha on pulmonary gas exchange and mechanics in premature lambs with respiratory distress syndrome. Pediatrics 2006; 117:295-303. [PMID: 16452346 DOI: 10.1542/peds.2005-0378] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Animal-derived, protein-containing surfactants seem to be superior to protein-free surfactants. Lucinactant, a synthetic surfactant containing a surfactant protein-B peptide analog, has been shown to be effective in animal models and phase II clinical trials. To date, lucinactant has not been compared with an animal-derived surfactant in a premature animal model. OBJECTIVE The objective was to compare the acute and sustained effects of lucinactant among premature lambs with respiratory distress syndrome (RDS) with the effects of a natural porcine surfactant (poractant-alpha). METHODS After 5 minutes of mechanical ventilation twin premature lambs were assigned randomly to the lucinactant group (30 mg/mL, 5.8 mL/kg) or the poractant-alpha group (80 mg/mL, 2.2 mL/kg). Heart rate, systemic arterial pressure, arterial pH, blood gas values, and lung mechanics were recorded for 12 hours. RESULTS Baseline fetal pH values were similar for the 2 groups (pH 7.27). After 5 minutes of mechanical ventilation, severe RDS developed (pH: <7.08; Paco2: >80 mm Hg; Pao2: <40 mm Hg; dynamic compliance: <0.08 mL/cm H2O per kg). After surfactant instillation, similar improvements in gas exchange and lung mechanics were observed for the lucinactant and poractant-alpha groups at 1 hour (pH: 7.3 +/- 0.1 vs 7.4 +/- 0.1; Paco2: 8 +/- 18 mm Hg vs 40 +/- 8 mm Hg; Pao2: 167 +/- 52 mm Hg vs 259 +/- 51 mm Hg; dynamic compliance: 0.3 +/- 0.1 mL/cm H2O per kg vs 0.3 +/- 0.1 mL/cm H2O per kg). The improvements in lung function were sustained, with no differences between groups. Cardiovascular profiles remained stable in both groups. CONCLUSIONS Among preterm lambs with severe RDS, lucinactant produced improvements in gas exchange and lung mechanics similar to those observed with a porcine-derived surfactant.
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Affiliation(s)
- Elena Gastiasoro-Cuesta
- Department of Pediatrics, Hospital de Cruces, University of the Basque Country, Barakaldo, Bizkaia, Spain
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18
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Hilgendorff A, Doerner M, Rawer D, Leick J, Trotter A, Ebsen M, Ruppert C, Günther A, Gortner L, Reiss I. Effects of a recombinant surfactant protein-C-based surfactant on lung function and the pulmonary surfactant system in a model of meconium aspiration syndrome. Crit Care Med 2006; 34:203-10. [PMID: 16374175 DOI: 10.1097/01.ccm.0000190624.77908.e2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Meconium aspiration syndrome (MAS) remains a relevant cause of neonatal respiratory failure and is characterized by severe impairment of pulmonary gas exchange, surfactant inactivation, and pronounced inflammatory changes. Surfactant administration has been shown as an effective treatment strategy in MAS. The present study aimed at investigating the impact of a recombinant surfactant protein (SP)-C-based surfactant on pulmonary gas exchange and lung function in this model of neonatal lung injury. Furthermore, SP-B and -C were determined on the transcriptional and protein level. DESIGN Laboratory experiment. SETTING University laboratory. SUBJECTS Twenty three newborn piglets (median age 6 days, weight 1900-2500 g). INTERVENTIONS Piglets were intubated and mechanically ventilated and then received 20% sterile meconium (5 mL/kg) for induction of lung injury. After 30 mins, animals were randomized for control (n = 7, MAS controls), recombinant SP-C surfactant (n = 8), or natural surfactant (n = 8). Surfactant preparations were administered as an intratracheal bolus (75 mg/kg), and animals were ventilated for another 330 mins. Nonventilated newborn piglets at term (n = 28; median weight 1484 g, range 720-1990 g) served as a healthy reference group (healthy controls). MEASUREMENTS AND MAIN RESULTS Lung function variables, arterial blood gas samples, and lung tissues were obtained. Expression of SP-B and -C messenger RNA was quantified in left lung lobe tissue using real-time polymerase chain reaction. Protein concentrations were determined by enzyme-linked immunosorbent assay. Scanning electron microscopy and transmission electron microscopy were performed in tissue samples of the right lung lobe. Compared with healthy controls, SP-B messenger RNA expression was significantly increased in MAS (p < .02), whereas SP-C messenger RNA expression was found to be significantly reduced (p < .001). SP concentrations, however, were not significantly different. Although a significant improvement of gas exchange and lung function was observed after surfactant administration in both groups, surfactant messenger RNA expression and protein concentrations were not significantly altered. Scanning and transmission electron microscopy showed severe pulmonary ultrastructural changes after meconium aspiration improving after surfactant treatment. CONCLUSIONS Impairment of lung function in MAS, associated with marked changes in SP messenger RNA expression, can be sufficiently treated using recombinant SP-C-based or natural surfactant. Despite improved lung function and gas exchange as well as pulmonary ultrastructure after treatment, pulmonary SP messenger RNA expression and concentrations remained significantly affected, giving important insight into the time course following surfactant treatment in MAS.
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Affiliation(s)
- Anne Hilgendorff
- Department of Pediatrics and Neonatology, Justus-Liebig-University Giessen, Germany
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19
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Meyerholz DK, Kawashima K, Gallup JM, Grubor B, Ackermann MR. Expression of select immune genes (surfactant proteins A and D, sheep beta defensin 1, and toll-like receptor 4) by respiratory epithelia is developmentally regulated in the preterm neonatal lamb. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2006; 30:1060-9. [PMID: 16510184 PMCID: PMC2791064 DOI: 10.1016/j.dci.2006.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 12/20/2005] [Accepted: 01/06/2006] [Indexed: 05/06/2023]
Abstract
Preterm infants experience enhanced susceptibility and severity to respiratory syncytial virus (RSV) infection. Terminal airway epithelium is an important site of RSV infection and the extent of local innate immune gene expression is poorly understood. In this study, expression of surfactant proteins A and D (SP-AD), sheep beta defensin 1 (SBD1), and toll-like receptor 4 (TLR4) mRNA were determined in whole lung homogenates from lambs. SP-AD and TLR4 mRNA expression increased (p < 0.05) from late gestation to term birth. In addition, gene expression of LCM-retrieved type II pneumocytes (CD208+), adjacent epithelium (CD208-) and bronchial epithelium demonstrated that bronchiole-alveolar junction epithelium (combined CD208 +/-) had significant (p < 0.05) developmental increases in SP-AD, SBD1 and TLR4 mRNA, whereas CD208+ cells had statistically significant increases only with SP-A mRNA. Using immunofluorescence, SP-AD antigen distribution and intensity were also greater with developmental age. These studies show reduced SBD1, SP-AD, and TLR4 expression in the preterm lung and this may underlie enhanced RSV susceptibility.
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Affiliation(s)
- David K Meyerholz
- Department of Veterinary Pathology, 2740 College of Veterinary Medicine, Iowa State University, Ames, IA 50011-1250, USA.
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20
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Shashikant BN, Miller TL, Welch RW, Pilon AL, Shaffer TH, Wolfson MR. Dose response to rhCC10-augmented surfactant therapy in a lamb model of infant respiratory distress syndrome: physiological, inflammatory, and kinetic profiles. J Appl Physiol (1985) 2005; 99:2204-11. [PMID: 16081627 DOI: 10.1152/japplphysiol.00246.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
While surfactant (SF) therapy alone improves respiratory distress syndrome (RDS)-associated gas exchange and lung stability, absence of anti-inflammatory proteins limits efficacy with respect to inflammation. Clara cell secretory protein (CC10), deficient in preterm infants, prevents SF degradation and has anti-inflammatory properties. In this study, intratracheal recombinant human (rh) CC10 (Claragen)-augmented SF (Survanta, Ross) therapy was examined in a premature lamb model of RDS with respect to inflammation and kinetic dose-response profiles. Preterm lambs (n = 24; gestational age: 126 +/- 3 days) were delivered via cesarean section, sedated, ventilated, and randomized into groups: 100 mg/kg SF, 100 mg/kg SF followed by 0.5 mg/kg rhCC10, 100 mg/kg SF followed by 1.5 mg/kg rhCC10, and 100 mg/kg SF followed by 5.0 mg/kg rhCC10. Arterial blood chemistry and lung mechanics were monitored; lungs were lavaged and snap-frozen after 4 h. TNF-alpha, IL-8 in plasma; TNF-alpha, IL-6, IL-8, myeloperoxidase in lung; and rhCC10 in plasma, urine, bronchoalveolar lavage, and lung were analyzed. Improvement in compliance, peak inspiratory pressure, and ventilatory efficiency index were greatest (P < 0.05) with SF + 5.0 mg/kg rhCC10. Plasma, urine, bronchoalveolar lavage, and lung [rhCC10] (where brackets denote concentration) increased (P < 0.01) with dose. Plasma [IL-8] was lower (P < 0.05) with rhCC10 than SF alone. Treatment with at least 1.5 mg/kg rhCC10 resulted in lower (P < 0.05) lung [TNF-alpha], [IL-8], and [myeloperoxidase]; SF + 1.5 mg/kg rhCC10 group had lower (P < 0.05) lung [IL-6], compared with all other groups. Compared with SF alone, SF augmented with at least 1.5 mg/kg rhCC10 decreased RDS-induced lung and systemic inflammation. Given that inflammation may lead to functional compromise, these data suggest that early intervention with rhCC10 may enhance SF therapy and warrant longer duration studies to determine its role to decrease long-term complications of ventilator management.
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Affiliation(s)
- Beth N Shashikant
- Dept. of Physiology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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21
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Ankermann T, Reisner A, Wiemann T, Krams M, Köhler H, Krause MF. Topical inhibition of nuclear factor-κB enhances reduction in lung edema by surfactant in a piglet model of airway lavage. Crit Care Med 2005; 33:1384-91. [PMID: 15942360 DOI: 10.1097/01.ccm.0000166371.18066.5e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Acute respiratory distress syndrome is occasionally seen in newborn infants due to a severe inflammatory process in the lungs that affects capillary-alveolar permeability, epithelial integrity, and type I and II pneumocyte function. The aim of this study was to investigate the effect of a topically applied nuclear factor-kappaB inhibitor (IkappaB kinase-NF-kappaB essential modulator binding domain [IKK-NBD] peptide) on gas exchange, lung function, lung fluids, and inflammation in a piglet model of repeated airway lavage that is characterized by surfactant deficiency, lung edema, and an inflammatory response. DESIGN Prospective, randomized, controlled animal study. SETTING Research laboratory of a university children's hospital. SUBJECTS A total of 24 anesthetized, mechanically ventilated newborn piglets. INTERVENTIONS Repeated airway lavage was carried out until both the Pao2 decreased to approximately 40 mm Hg, while ventilating the piglets with an Fio2 of 0.6, and a peak inspiratory pressure of >/=18 cm H2O was needed to maintain tidal volume at 6 mL/kg. One group of piglets served as a control (n = 8), a second group (S, n = 8) received a porcine surfactant preparation (Curosurf), and a third group received IKK-NBD peptide admixed to surfactant (S+IN, n = 8). MEASUREMENTS AND MAIN RESULTS After 6 hrs of mechanical ventilation after intervention, S+IN group piglets showed decreased extravascular lung water (S+IN vs. S, 20 +/- 3 vs. 28 +/- 10 mL/kg; p < .05) and a lesser protein content in the epithelial lining fluid (S+IN vs. S, 38 +/- 5 vs. 50 +/- 5 mg/L; p < .05). Functional residual capacity (S+IN vs. S, 16.7 +/- 6.3 vs. 12.2 +/- 4.3 mL/kg; p < .05), alveolar volume (S+IN vs. S, 5.4 +/- 1.8 vs. 4.6 +/- 1.5 mL/kg; p < .05), and lung mechanics were improved. Bronchoalveolar lavage showed a lesser percentage of polymorphonuclear leukocytes (S+IN vs. S, 70% +/- 6% vs. 82% +/- 3%; p < .01) and a reduction in the chemokine leukotriene B4 (S+IN vs. S, 2.0 +/- 0.6 vs. 3.5 +/- 1.4 pg/mL; p < .01). CONCLUSIONS A topically applied nuclear factor-kappaB inhibitor improves lung edema and lung volumes and reduces inflammation in this newborn piglet model of airway lavage.
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Affiliation(s)
- Tobias Ankermann
- Department of Pediatrics, Christian-Albrechts-University, Kiel, Germany
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22
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Krause MF, Wiemann T, Reisner A, Orlowska-Volk M, Köhler H, Ankermann T. Surfactant reduces extravascular lung water and invasion of polymorphonuclear leukocytes into the lung in a piglet model of airway lavage. Pulm Pharmacol Ther 2004; 18:129-39. [PMID: 15649855 DOI: 10.1016/j.pupt.2004.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 10/29/2004] [Accepted: 11/07/2004] [Indexed: 10/26/2022]
Abstract
Acute respiratory distress syndrome (ARDS) in newborns and young infants is linked with an inflammatory response of the lungs which affects the capillary-alveolar permeability, epithelial integrity and type I and II pneumocyte function. Abundant extravascular lung water with a high protein content inactivates surfactant together with the enzymatic action of polymorphonuclear leukocytes (PMNL). We asked if a decrease in extravascular lung water and a reduction in lung infiltration with PMNL could be achieved by surfactant administration (Curosurf) within 6 h of mechanical ventilation when given in a newborn piglet model of repeated airway lavage. Improvements in gas exchange and lung mechanics were predominantly caused by resorption of extravascular lung water rather than by the reopening of alveolar atelectases. PMNL were significantly reduced in the bronchoalveolar lavage fluid after 6 h of mechanical ventilation. However, acute phase cytokines (IL-6, TNF-alpha) remained unchanged, except for IL-8 which increased after administration of surfactant. We conclude that the decrease in extravascular lung water and in infiltration with PMNL following surfactant administration is accomplished within 6 h through mechanisms different from attenuation of pro-inflammatory cytokines. Surfactant treatment for newborn and infant ARDS might therefore improve fluid overload and atelectasis and reduce PMNL infiltration.
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Affiliation(s)
- Martin F Krause
- Department of General Pediatrics, University Children's Hospital, Christian-Albrechts-University, Schwanenweg 20, D-24105 Kiel, Germany.
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Meyerholz DK, Grubor B, Fach SJ, Sacco RE, Lehmkuhl HD, Gallup JM, Ackermann MR. Reduced clearance of respiratory syncytial virus infection in a preterm lamb model. Microbes Infect 2004; 6:1312-9. [PMID: 15555538 PMCID: PMC2791065 DOI: 10.1016/j.micinf.2004.08.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 08/20/2004] [Indexed: 11/23/2022]
Abstract
Respiratory syncytial virus (RSV) causes significant respiratory disease in children worldwide. For the study of severe RSV disease seen in preterm infants, a suitable animal model is lacking. The novel hypothesis of this study was that preterm lambs are susceptible to bovine RSV (bRSV) infection, an analogous pneumovirus with ruminant host specificity, and that there would be age-dependent differences in select RSV disease parameters. During RSV infection, preterm lambs had elevated temperatures and respiration rates with mild anorexia and cough compared to controls. Gross lesions included multifocal consolidation and atelectasis with foci of hyperinflation. Microscopic lesions included multifocal alveolar septal thickening and bronchiolitis. Immunohistochemistry localized the RSV antigen to all layers of bronchiolar epithelium from a few basal cells to numerous sloughing epithelia. A few mononuclear cells were also immunoreactive. To assess for age-dependent differences in RSV infection, neonatal lambs were infected similarly to the preterm lambs or with a high-titer viral inoculum. Using morphometry at day 7 of infection, preterm lambs had significantly more cellular immunoreactivity for RSV antigen (P <0.05) and syncytial cell formation (P <0.05) than either group of neonatal lambs. This work suggests that perinatal RSV clearance is age-dependent, which may explain the severity of RSV infection in preterm infants. The preterm lamb model is useful for assessing age-dependent mechanisms of severe RSV infection.
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Affiliation(s)
- David K Meyerholz
- Department of Veterinary Pathology, Iowa State University, 2740 Veterinary Medicine, Ames, IA 50011-1250, USA.
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24
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Abstract
Interleukin-1alpha is an early response proinflammatory cytokine that has been associated with chorioamnionitis and preterm labor, brain injury, and bronchopulmonary dysplasia. However, IL-1alpha also can increase expression of surfactant proteins and induce lung maturation in the preterm fetus. We measured the effects of IL-1alpha given by intratracheal instillation (IT) and compared the responses with injection of i.v. IL-1alpha in surfactant-treated and ventilated premature lambs. IT recombinant ovine IL-1alpha at doses of 5 and 50 microg/kg caused a similar large recruitment of neutrophils into the bronchoalveolar lavage fluid. The neutrophils expressed CD11b, CD14, and CD44, but did not produce increased amounts of H(2)O(2). Cells from the bronchoalveolar lavage fluid had increased expression of proinflammatory cytokines, which also were increased in mRNA from lung tissue. The IT IL-1alpha also suppressed the expression of surfactant protein-C mRNA. Systemic effects were decreased neutrophils in blood, decreased lung function, increased heart rate, and hypotension or death in the 50 microg/kg IL-1alpha IT group and only decreased neutrophils in the blood in the 5 microg/kg IL-1alpha IT group. The i.v. IL-1alpha caused no lung inflammation or injury but did result in severe neutropenia and hypotension leading to early death. IT IL-1alpha can cause intense lung inflammation and systemic shock in ventilated preterm lungs.
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Affiliation(s)
- Neil Mulrooney
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA
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25
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Ikegami M, Kallapur SG, Jobe AH. Initial responses to ventilation of premature lambs exposed to intra-amniotic endotoxin 4 days before delivery. Am J Physiol Lung Cell Mol Physiol 2004; 286:L573-9. [PMID: 14617517 DOI: 10.1152/ajplung.00211.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Preterm delivery is frequently preceded by chorioamnionitis, resulting in exposure of the fetal lung to inflammation. We hypothesized that ventilation of the antenatally inflamed lung would result in amplification of the lung injury. Therefore, we induced fetal lung inflammation with intra-amniotic endotoxin (10 mg of Escherichia coli 055:B5) 4 days before premature delivery at 130 days of gestation. Lung function and lung inflammation after surfactant treatment and 4 h of mechanical ventilation were evaluated. Inflammatory cell numbers in amniotic fluid were increased >10-fold by antenatal endotoxin exposure. Antenatal endotoxin exposure had minimal effects on blood pressure, heart rate, lung compliance, and blood gas values. The endotoxin-exposed lungs required higher ventilation pressures. Ventilation did not increase the number of inflammatory cells or the protein in bronchoalveolar lavage fluid of the endotoxin-exposed animals above that measured in endotoxin-exposed fetuses that were not ventilated. IL-1β, IL-6, and IL-8 mRNA in cells from bronchoalveolar lavage fluid were increased by antenatal endotoxin exposure but not changed by ventilation. IL-1β and IL-8 protein was increased in lung tissue by 4 h of ventilation. Very little inflammation was induced by ventilation in this premature lamb model of surfactant treatment and gentle ventilation. After lung inflammation was induced by intra-amniotic endotoxin injection, ventilation did not increase lung injury.
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Affiliation(s)
- Machiko Ikegami
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA.
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26
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Hilgendorff A, Rawer D, Doerner M, Tutdibi E, Ebsen M, Schmidt R, Guenther A, Gortner L, Reiss I. Synthetic and natural surfactant differentially modulate inflammation after meconium aspiration. Intensive Care Med 2003; 29:2247-2254. [PMID: 12955179 DOI: 10.1007/s00134-003-1984-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2003] [Accepted: 07/28/2003] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Meconium aspiration syndrome remains a relevant cause of neonatal respiratory failure and is associated with severe pulmonary changes including surfactant inactivation and pronounced inflammatory changes. The present study investigated the effect of two different surfactant preparations-recombinant surfactant protein C surfactant (rSP-C Surf) and natural bovine surfactant-on pulmonary gas exchange and inflammatory response. DESIGN AND SUBJECTS Twenty-three newborn piglets were intubated, mechanically ventilated, received 5 ml/kg 20% sterile meconium for induction of lung injury, and were randomized thereafter for controls ( n=7), rSP-C Surf ( n=8), or natural surfactant ( n=8). Surfactants were given as an intratracheal bolus (75 mg/kg) and animals were further ventilated. MEASUREMENTS AND RESULTS Lung function variables, arterial blood gas samples and lung tissues were obtained. Histological evaluation was performed in right lung tissue using an established score. Cytokine mRNA expression (left lung tissue) was quantified using TaqMan real-time PCR (DeltaDeltaCT method, normalized to controls). In addition to significant improvement in gas exchange and lung function, histological evaluation showed significantly lower sum scores in the rSP-C Surf group than in controls). Cytokine mRNA expression of IL-1beta in whole lung tissue was significantly lower after administration of rSP-C Surf than in natural surfactant and controls whereas IL-10 mRNA expression was significantly induced in both surfactant groups. CONCLUSIONS Surfactant administration improved both gas exchange and pulmonary inflammatory cytokine transcription. Mechanisms underlying the differential inflammatory response in both surfactant preparations need to be further addressed.
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Affiliation(s)
- Anne Hilgendorff
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany.
| | - Daniel Rawer
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Martin Doerner
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Erol Tutdibi
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Michael Ebsen
- Department of Pathology, University of Bochum, Bochum, Germany
| | - Reinhold Schmidt
- Department of Internal Medicine, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Andreas Guenther
- Department of Internal Medicine, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Ludwig Gortner
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Irwin Reiss
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
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Cogo PE, Zimmermann LJI, Meneghini L, Mainini N, Bordignon L, Suma V, Buffo M, Carnielli VP. Pulmonary surfactant disaturated-phosphatidylcholine (DSPC) turnover and pool size in newborn infants with congenital diaphragmatic hernia (CDH). Pediatr Res 2003; 54:653-8. [PMID: 12904604 DOI: 10.1203/01.pdr.0000084344.42409.c6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In animal CDH models, surfactant deficiency contributes to the pathophysiology of the condition but information on human disease is very limited. The aim of our study was to investigate surfactant kinetics in CDH newborns. We studied surfactant disaturated-phosphatidylcholine (DSPC) half-life, turnover and apparent pool size by stable isotope methodology in CDH newborns with no ExtraCorporeal Membrane Oxygenation (ECMO) support (n = 13, birth weight (BW) 3.2 +/- 2.2 kg, gestational age (GA) 39 +/- 0.4 wks, postnatal age 43 +/- 11 h) and in 8 term infants with no lung disease (CONTROLS, BW 2.7 +/- 0 kg, GA 38 +/- 0.8 wks, postnatal age 96 +/- 26 h). We administered a trace dose of 13C-palmitic acid dipalmitoyl-phosphatidylcholine (DPPC) through the endotracheal (ET) tube and we measured DSPC kinetics by gas chromatography-mass spectrometry from DSPC13C-enrichment decay curves obtained from sequential tracheal aspirates. DSPC amount from tracheal aspirates (TA-DSPC) was measured by gas chromatography. In CDH infants DSPC half-life was shorter (24 +/- 4 and 53 +/- 11 h, p = 0.01), turnover faster (0.6 +/- 0.1 and 1.5 +/- 0.3 d-1 p = 0.01), apparent pool size smaller (34 +/- 6 and 57 +/- 7 mg/kg body weight, p = 0.02) and tracheal aspirates DSPC amount lower (2.4 +/- 0.4 and 4.6 +/- 0.5 mg/mL Epithelial Lining Fluid (ELF), p = 0.007) than in CONTROLS. In conclusion surfactant kinetics is grossly abnormal in mechanically ventilated CDH. Whether alterations of DSPC kinetics in CDH infants are caused by a primary surfactant deficiency or are secondary to oxygen therapy and ventilator support has still to be determined.
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Affiliation(s)
- Paola E Cogo
- Department of Pediatrics, University of Padova, Padova, Italy.
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28
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Ikegami M, Moss TJM, Kallapur SG, Mulrooney N, Kramer BW, Nitsos I, Bachurski CJ, Newnham JP, Jobe AH. Minimal lung and systemic responses to TNF-alpha in preterm sheep. Am J Physiol Lung Cell Mol Physiol 2003; 285:L121-9. [PMID: 12611817 DOI: 10.1152/ajplung.00393.2002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
TNF-alpha has been associated with chorioamnionitis and the subsequent development of bronchopulmonary dysplasia in preterm infants. We asked whether bioactive recombinant ovine TNF-alpha could induce chorioamnionitis, lung inflammation, lung maturation, and systemic effects in fetal sheep. We compared the responses to IL-1alpha, a cytokine known to induce these responses in preterm sheep. Intra-amniotic TNF-alpha caused no chorioamnionitis, no lung maturation, and a very small increase in inflammatory cells in the fetal lung after 5 h, 2 days (d), and 7 d. In contrast, IL-1alpha induced inflammation and lung maturation. TNF-alpha given into the airways at birth increased granulocytes in the bronchoalveolar lavage fluid of ventilated preterm lungs and decreased the mRNA for surfactant protein C but did not adversely effect postnatal lung function. An intravascular injection of IL-1alpha caused a systemic inflammatory response in fetal sheep, whereas there was no fetal response to intravascular TNF-alpha. Fetal and newborn preterm sheep are minimally responsive to TNF-alpha. Therefore, the presence of a mediator such as TNF-alpha in a developing animal does not necessarily mean that it is causing the responses anticipated from previous results in adult animals.
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Affiliation(s)
- Machiko Ikegami
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, 3333 Burnet Ave., Cincinnati, OH 45229-3039, USA.
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29
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Abstract
The preterm infant has functionally immature monocytes. The effects of common clinical interventions and exposures that might modulate inflammation were evaluated using monocytes isolated from blood of preterm lambs [130 d gestational age (GA)], near-term lambs (141 d GA), and adult sheep. Endotoxin stimulated hydrogen peroxide production by adult monocytes, but monocytes from 130-d and 141-d GA lambs had a reduced and delayed hydrogen peroxide production. Endotoxin did not decrease apoptosis of monocytes from 130-d and 141-d GA lambs but decreased apoptosis of adult monocytes. Dexamethasone increased the phagocytosis of bacteria and apoptotic cells by adult monocytes by 35% but not by monocytes from 130-d and 141-d GA lambs. Synthetic and natural surfactants and dipalmitoylphosphatidylcholine increased phagocytosis of apoptotic cells by monocytes from preterm, term, and adult sheep. Monocytes from preterm and term lambs differ from adult monocytes in tests of both the initiation and the resolution of inflammation. The reduced phagocytosis of apoptotic cells by monocytes from the preterm may contribute to prolonged inflammation in diseases such as bronchopulmonary dysplasia.
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Affiliation(s)
- Boris W Kramer
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, Cincinnati, OH 45229-3039, USA
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30
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Cogo PE, Zimmermann LJI, Pesavento R, Sacchetto E, Burighel A, Rosso F, Badon T, Verlato G, Carnielli VP. Surfactant kinetics in preterm infants on mechanical ventilation who did and did not develop bronchopulmonary dysplasia. Crit Care Med 2003; 31:1532-8. [PMID: 12771629 DOI: 10.1097/01.ccm.0000063043.25167.99] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To characterize surfactant kinetics in vivo in two groups of premature infants on different levels of mechanical ventilation and at different risk of developing bronchopulmonary dysplasia. DESIGN Controlled observational study in two independent groups of infants. SETTING Neonatal intensive care unit. PATIENTS Thirteen preterm infants (26 +/- 0.5 wks, birth weight 801 +/- 64 g) on high ventilatory setting and who finally all developed bronchopulmonary dysplasia (MechVentBPD), and eight (26 +/- 0.5 wks, birth weight 887 +/- 103 g) who had minimal or no lung disease and of whom none developed bronchopulmonary dysplasia (MechVentNoBPD). MEASUREMENTS AND MAIN RESULTS Endotracheal 13C-labeled dipalmitoyl-phosphatidylcholine was administered and subsequent measurements of the 13C enrichment of surfactant-disaturated phosphatidylcholine (DSPC) from serial tracheal aspirates were made by gas chromatography-mass spectrometry. We calculated disaturated phosphatidylcholine pharmacokinetic variables in terms of half-life and apparent pool size from the enrichment decay curves over time. DSPC concentration from tracheal aspirates was expressed as milligrams/milliliter epithelial lining fluid (ELF-DSPC). Data are presented as mean +/- se. In MechVentBPD infants vs. MechVentNoBPD, ELF-DSPC was much reduced, 2.9 +/- 0.6 vs. 9.4 +/- 3.0 mg/mL ELF (p =.03), half-life was shorter, 19.4 +/- 2.8 vs. 42.5 +/- 6.3 hrs (p =.002), and apparent pool size larger, 136 +/- 21 vs. 65.8 +/- 16.0 mg/kg (p =.057). In MechVentBPD, apparent DSPC pool size positively correlated with mean airway pressure x Fio(2) and inversely correlated with ELF-DSPC. ELF-DSPC was inversely correlated with mean airway pressure x Fio(2). No significant correlations were found in the MechVentNoBPD group. CONCLUSIONS MechVentBPD infants showed profound alteration of surfactant kinetics compared with preterm infants with minimal lung disease, and these alterations were correlated with severity of ventilatory support.
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Affiliation(s)
- Paola E Cogo
- Department of Pediatrics, University of Padova, Italy
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Abstract
High PCO(2) levels attenuate reperfusion injury and ventilation-induced injury in isolated and perfused lungs. We asked whether premature lambs could tolerate 6 h of ventilation with a PCO(2) >80 mm Hg and whether the high PCO(2) modulated the ventilator-induced injury. Preterm surfactant-treated lambs were ventilated for 30 min with a high tidal volume (V(T)) to induce lung injury. The lambs then were ventilated for 5.5 h with a V(T) of 6-9 mL/kg to achieve a PCO(2) of 40-50 mm Hg in the control group. CO(2) was added to the ventilator circuit of a high PCO(2) group to maintain an average PCO(2) of 95 +/- 5 mm Hg. The high PCO(2) lambs had heart rates, blood pressures, plasma cortisol values, and oxygenation equivalent to the control lambs. The lungs of the high PCO(2) group had significantly higher gas volumes and had less lung injury by histopathology. Indicators of inflammation (white blood cells, hydrogen peroxide production, and IL-1beta and IL-8 cytokine mRNA expression in cells from the alveolar wash) qualitatively indicated less injury in the high PCO(2) group, although the differences were not significant. Preterm lambs tolerated a very high PCO(2) without physiologic compromise for 6 h. The high PCO(2) may attenuate ventilator-induced lung injury in the preterm.
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Affiliation(s)
- Marya Strand
- Division of Pulmonary Biology, Cincinnati Children's Hospital, Cincinnati, Ohio 45229-3039, USA
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Ikegami M, Jobe AH. Postnatal lung inflammation increased by ventilation of preterm lambs exposed antenatally to Escherichia coli endotoxin. Pediatr Res 2002; 52:356-62. [PMID: 12193667 DOI: 10.1203/00006450-200209000-00008] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Chorioamnionitis resulting in exposure of the fetal lung to inflammation is frequent before preterm delivery. The initiation of mechanical ventilation in the preterm recruits granulocytes to the lungs and increases proinflammatory cytokine expression in the lungs. We hypothesized that when the prematurely born newborn with chorioamnionitis was ventilated, inflammation would increase. Therefore, we asked whether inflammatory exposure to the fetal lung caused by intra-amniotic endotoxin (10 mg, Escherichia coli 055:beta 5) given at 100 d gestation would alter the inflammatory responses to the mechanical ventilation in surfactant-treated preterm lambs delivered at 130 d gestation. Cells in alveolar washes, proinflammatory cytokine expression, and surfactant protein mRNA expression were not different for saline and endotoxin exposed lambs that were not ventilated. The endotoxin- and saline-exposed control animals had similar lung function for 6 h of ventilation. Bronchoalveolar lavage fluid from the ventilated and antenatal endotoxin-exposed animals contained 5.7 times more monocytes, 12 times more lymphocytes, and a nonsignificant increase in neutrophils. Cells from the bronchoalveolar lavage fluid expressed 3-fold more IL-6 and IL-8 mRNA than did cells from the saline exposed comparison animals. An antenatal exposure of the fetal lung to endotoxin enhanced the subsequent inflammatory response of the ventilated preterm lung.
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Affiliation(s)
- Machiko Ikegami
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, Cincinnati, Ohio 45229-3039, USA.
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