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Stojanovska V, Barton SK, Tolcos M, Gill AW, Kluckow M, Miller SL, Zahra V, Hooper SB, Galinsky R, Polglase GR. The Effect of Antenatal Betamethasone on White Matter Inflammation and Injury in Fetal Sheep and Ventilated Preterm Lambs. Dev Neurosci 2019; 40:497-507. [PMID: 30840951 DOI: 10.1159/000496466] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/20/2018] [Indexed: 11/19/2022] Open
Abstract
Antenatal administration of betamethasone (BM) is a common antecedent of preterm birth, but there is limited information about its impact on the acute evolution of preterm neonatal brain injury. We aimed to compare the effects of maternal BM in combination with mechanical ventilation on the white matter (WM) of late preterm sheep. At 0.85 of gestation, pregnant ewes were randomly assigned to receive intra-muscular (i.m.) saline (n = 9) or i.m. BM (n = 13). Lambs were delivered and unventilated controls (UVCSal, n = 4; UVCBM, n = 6) were humanely killed without intervention; ventilated lambs (VentSal, n = 5; VentBM, n = 7) were injuriously ventilated for 15 min, followed by conventional ventilation for 75 min. Cardiovascular and cerebral haemodynamics and oxygenation were measured continuously. The cerebral WM underwent assessment of inflammation and injury, and oxidative stress was measured in the cerebrospinal fluid (CSF). In the periventricular and subcortical WM tracts, the proportion of amoeboid (activated) microglia, the density of astrocytes, and the number of blood vessels with protein extravasation were higher in UVCBM than in UVCSal (p < 0.05 for all). During ventilation, tidal volume, mean arterial pressure, carotid blood flow, and oxygen delivery were higher in -VentBM lambs (p < 0.05 vs. VentSal). In the subcortical WM, microglial infiltration was increased in the VentSal group compared to UVCSal. The proportion of activated microglia and protein extravasation was higher in the VentBM group compared to VentSal within the periventricular and subcortical WM tracts (p < 0.05). CSF oxidative stress was increased in the VentBM group compared to UVCSal, UVCBM, and VentSal groups (p < 0.05). Antenatal BM was associated with inflammation and vascular permeability in the WM of late preterm fetal sheep. During the immediate neonatal period, the increased carotid perfusion and oxygen delivery in BM-treated lambs was associated with increased oxidative stress, microglial activation and microvascular injury.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Samantha K Barton
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, The University of Western Australia, Crawley, Washington, Australia
| | - Martin Kluckow
- Department of Neonatal Medicine, Royal North Shore Hospital and University of Sydney, Sydney, New South Wales, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Valerie Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia, .,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia,
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Moss TJM, Westover AJ. Inflammation-induced preterm lung maturation: lessons from animal experimentation. Paediatr Respir Rev 2017; 23:72-77. [PMID: 27856214 DOI: 10.1016/j.prrv.2016.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 07/08/2016] [Accepted: 10/05/2016] [Indexed: 02/05/2023]
Abstract
Intrauterine inflammation, or chorioamnionitis, is a major contributor to preterm birth. Prematurity per se is associated with considerable morbidity and mortality resulting from lung immaturity but exposure to chorioamnionitis reduces the risk of neonatal respiratory distress syndrome (RDS) in preterm infants. Animal experiments have identified that an increase in pulmonary surfactant production by the preterm lungs likely underlies this decreased risk of RDS in infants exposed to chorioamnionitis. Further animal experimentation has shown that infectious or inflammatory agents in amniotic fluid exert their effects on lung development by direct effects within the developing respiratory tract, and probably not by systemic pathways. Differences in the effects of intrauterine inflammation and glucocorticoids demonstrate that canonical glucocorticoid-mediated lung maturation is not responsible for inflammation-induced changes in lung development. Animal experimentation is identifying alternative lung maturational pathways, and transgenic animals and cell culture techniques will allow identification of novel mechanisms of lung maturation that may lead to new treatments for the prevention of RDS.
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Affiliation(s)
- Timothy J M Moss
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia; Department of Obstetrics and Gynecology, Monash University, Clayton, VIC 3168, Australia.
| | - Alana J Westover
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia
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Hanita T, Matsuda T, Saito M, Kitanishi R, Cho K, Harding R, Kobayashi Y. Potential Role of Prenatal Inflammation in the Impairment of Lung Development Following Mechanical Ventilation of Preterm Lambs. Reprod Sci 2016; 24:478-487. [DOI: 10.1177/1933719116660846] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Takushi Hanita
- Center for Perinatal and Neonatal Care, Tohoku University Hospital, Sendai, Miyagi, Japan
- Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Tadashi Matsuda
- Center for Perinatal and Neonatal Care, Tohoku University Hospital, Sendai, Miyagi, Japan
| | - Masatoshi Saito
- Center for Perinatal and Neonatal Care, Tohoku University Hospital, Sendai, Miyagi, Japan
| | - Ryuta Kitanishi
- Center for Perinatal and Neonatal Care, Tohoku University Hospital, Sendai, Miyagi, Japan
| | - Kazutoshi Cho
- Department of Obstetrics and Gynecology, Hokkaido University Hospital, Sapporo, Japan
| | - Richard Harding
- Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Yoshiyasu Kobayashi
- Department of Veterinary Pathology, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
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Lakshminrusimha S, Mathew B, Nair J, Gugino SF, Koenigsknecht C, Rawat M, Nielsen L, Swartz DD. Tracheal suctioning improves gas exchange but not hemodynamics in asphyxiated lambs with meconium aspiration. Pediatr Res 2015; 77:347-55. [PMID: 25406897 PMCID: PMC4297526 DOI: 10.1038/pr.2014.186] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 08/14/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Current neonatal resuscitation guidelines recommend tracheal suctioning of nonvigorous neonates born through meconium-stained amniotic fluid. METHODS We evaluated the effect of tracheal suctioning at birth in 29 lambs with asphyxia induced by cord occlusion and meconium aspiration during gasping. RESULTS Tracheal suctioning at birth (n = 15) decreased amount of meconium in distal airways (53 ± 29 particles/mm(2) lung area) compared to no suction (499 ± 109 particles/mm(2); n = 14; P < 0.001). Three lambs in the suction group had cardiac arrest during suctioning, requiring chest compressions and epinephrine. Onset of ventilation was delayed in the suction group (146 ± 11 vs. 47 ± 3 s in no-suction group; P = 0.005). There was no difference in pulmonary blood flow, carotid blood flow, and pulmonary or systemic blood pressure between the two groups. Left atrial pressure was significantly higher in the suction group. Tracheal suctioning resulted in higher Pao2/FiO2 levels (122 ± 21 vs. 78 ± 10 mm Hg) and ventilator efficiency index (0.3 ± 0.05 vs.0.16 ± 0.03). Two lambs in the no-suction group required inhaled nitric oxide. Lung 3-nitrotyrosine levels were higher in the suction group (0.65 ± 0.03 ng/µg protein) compared with the no-suction group (0.47 ± 0.06). CONCLUSION Tracheal suctioning improves oxygenation and ventilation. Suctioning does not improve pulmonary/systemic hemodynamics or oxidative stress in an ovine model of acute meconium aspiration with asphyxia.
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Affiliation(s)
| | - Bobby Mathew
- Department of Pediatrics, University at Buffalo, Buffalo NY, USA
| | - Jayasree Nair
- Department of Pediatrics, University at Buffalo, Buffalo NY, USA
| | - Sylvia F. Gugino
- Department of Pediatrics, University at Buffalo, Buffalo NY, USA,Department of Physiology and Biophysics, University at Buffalo, Buffalo NY, USA
| | | | - Munmun Rawat
- Department of Pediatrics, University at Buffalo, Buffalo NY, USA
| | - Lori Nielsen
- Department of Pediatrics, University at Buffalo, Buffalo NY, USA
| | - Daniel D. Swartz
- Department of Pediatrics, University at Buffalo, Buffalo NY, USA,Department of Physiology and Biophysics, University at Buffalo, Buffalo NY, USA
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Polglase GR, Miller SL, Barton SK, Kluckow M, Gill AW, Hooper SB, Tolcos M. Respiratory support for premature neonates in the delivery room: effects on cardiovascular function and the development of brain injury. Pediatr Res 2014; 75:682-8. [PMID: 24614803 DOI: 10.1038/pr.2014.40] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 12/16/2013] [Indexed: 02/02/2023]
Abstract
The transition to newborn life in preterm infants is complicated by immature cardiovascular and respiratory systems. Consequently, preterm infants often require respiratory support immediately after birth. Although aeration of the lung underpins the circulatory transition at birth, positive pressure ventilation can adversely affect cardiorespiratory function during this vulnerable period, reducing pulmonary blood flow and left ventricular output. Furthermore, pulmonary volutrauma is known to initiate pulmonary inflammatory responses, resulting in remote systemic involvement. This review focuses on the downstream consequences of positive pressure ventilation, in particular, interactions between cardiovascular output and the initiation of a systemic inflammatory cascade, on the immature brain. Recent studies have highlighted that positive pressure ventilation strategies are precursors of cerebral injury, probably mediated through cerebral blood flow instability. The presence of, or initiation of, an inflammatory cascade accentuates adverse cerebral blood flow, in addition to being a direct source of brain injury. Importantly, the degree of brain injury is dependent on the nature of the initial ventilation strategy used.
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Affiliation(s)
- Graeme R Polglase
- 1] The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Samantha K Barton
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Martin Kluckow
- Department of Neonatalogy, Royal North Shore Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, The University of Western Australia, Western Australia, Australia
| | - Stuart B Hooper
- 1] The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Mary Tolcos
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
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