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Stojanovska V, Atta J, Kelly SB, Zahra VA, Matthews-Staindl E, Nitsos I, Moxham A, Pham Y, Hooper SB, Herlenius E, Galinsky R, Polglase GR. Increased Prostaglandin E2 in Brainstem Respiratory Centers Is Associated With Inhibition of Breathing Movements in Fetal Sheep Exposed to Progressive Systemic Inflammation. Front Physiol 2022; 13:841229. [PMID: 35309054 PMCID: PMC8928579 DOI: 10.3389/fphys.2022.841229] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/08/2022] [Indexed: 12/11/2022] Open
Abstract
Background Preterm newborns commonly experience apnoeas after birth and require respiratory stimulants and support. Antenatal inflammation is a common antecedent of preterm birth and inflammatory mediators, particularly prostaglandin E2 (PGE2), are associated with inhibition of vital brainstem respiratory centers. In this study, we tested the hypothesis that exposure to antenatal inflammation inhibits fetal breathing movements (FBMs) and increases inflammation and PGE2 levels in brainstem respiratory centers, cerebrospinal fluid (CSF) and blood plasma. Methods Chronically instrumented late preterm fetal sheep at 0.85 of gestation were randomly assigned to receive repeated intravenous saline (n = 8) or lipopolysaccharide (LPS) infusions (experimental day 1 = 300 ng, day 2 = 600 ng, day 3 = 1200 ng, n = 8). Fetal breathing movements were recorded throughout the experimental period. Sheep were euthanized 4 days after starting infusions for assessment of brainstem respiratory center histology. Results LPS infusions increased circulating and cerebrospinal fluid PGE2 levels, decreased arterial oxygen saturation, increased the partial pressure of carbon dioxide and lactate concentration, and decreased pH (p < 0.05 for all) compared to controls. LPS infusions caused transient reductions in the % of time fetuses spent breathing and the proportion of vigorous fetal breathing movements (P < 0.05 vs. control). LPS-exposure increased PGE2 expression in the RTN/pFRG (P < 0.05 vs. control) but not the pBÖTC (P < 0.07 vs. control) of the brainstem. No significant changes in gene expression were observed for PGE2 enzymes or caspase 3. LPS-exposure reduced the numbers of GFAP-immunoreactive astrocytes in the RTN/pFRG, NTS and XII of the brainstem (P < 0.05 vs. control for all) and increased microglial activation in the RTN/pFRG, preBÖTC, NTS, and XII brainstem respiratory centers (P < 0.05 vs. control for all). Conclusion Chronic LPS-exposure in late preterm fetal sheep increased PGE2 levels within the brainstem, CSF and plasma, and was associated with inhibition of FBMs, astrocyte loss and microglial activation within the brainstem respiratory centers. Further studies are needed to determine whether the inflammation-induced increase in PGE2 levels plays a key role in depressing respiratory drive in the perinatal period.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - John Atta
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Sharmony B. Kelly
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Valerie A. Zahra
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Eva Matthews-Staindl
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Ilias Nitsos
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Alison Moxham
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Yen Pham
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Stuart B. Hooper
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Eric Herlenius
- Department of Women’s and Children’s Health, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
- Astrid Lindgren Childrens Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Robert Galinsky
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- *Correspondence: Robert Galinsky,
| | - Graeme R. Polglase
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- Graeme R. Polglase,
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Kelly SB, Stojanovska V, Zahra VA, Moxham A, Miller SL, Moss TJM, Hooper SB, Nold MF, Nold-Petry CA, Dean JM, Bennet L, Polglase GR, Gunn AJ, Galinsky R. Interleukin-1 blockade attenuates white matter inflammation and oligodendrocyte loss after progressive systemic lipopolysaccharide exposure in near-term fetal sheep. J Neuroinflammation 2021; 18:189. [PMID: 34465372 PMCID: PMC8408978 DOI: 10.1186/s12974-021-02238-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 08/11/2021] [Indexed: 12/14/2022] Open
Abstract
Background Increased systemic and tissue levels of interleukin (IL)-1β are associated with greater risk of impaired neurodevelopment after birth. In this study, we tested the hypothesis that systemic IL-1 receptor antagonist (Ra) administration would attenuate brain inflammation and injury in near-term fetal sheep exposed to lipopolysaccharide (LPS). Methods Chronically instrumented near-term fetal sheep at 0.85 of gestation were randomly assigned to saline infusion (control, n = 9), repeated LPS infusions (0 h = 300 ng, 24 h = 600 ng, 48 h = 1200 ng, n = 8) or repeated LPS plus IL-1Ra infusions (13 mg/kg infused over 4 h) started 1 h after each LPS infusion (n = 9). Sheep were euthanized 4 days after starting infusions for histology. Results LPS infusions increased circulating cytokines and were associated with electroencephalogram (EEG) suppression with transiently reduced mean arterial blood pressure, and increased carotid artery perfusion and fetal heart rate (P < 0.05 vs. control for all). In the periventricular and intragyral white matter, LPS-exposure increased IL-1β immunoreactivity, numbers of caspase 3+ cells and microglia, reduced astrocyte and olig-2+ oligodendrocyte survival but did not change numbers of mature CC1+ oligodendrocytes, myelin expression or numbers of neurons in the cortex and subcortical regions. IL-1Ra infusions reduced circulating cytokines and improved recovery of EEG activity and carotid artery perfusion. Histologically, IL-1Ra reduced microgliosis, IL-1β expression and caspase-3+ cells, and improved olig-2+ oligodendrocyte survival. Conclusion IL-1Ra improved EEG activity and markedly attenuated systemic inflammation, microgliosis and oligodendrocyte loss following LPS exposure in near-term fetal sheep. Further studies examining the long-term effects on brain maturation are now needed. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02238-4.
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Affiliation(s)
- Sharmony B Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Valerie A Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Alison Moxham
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Timothy J M Moss
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Marcel F Nold
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Paediatrics, Monash University, Melbourne, Victoria, Australia.,Monash Newborn, Monash Children's Hospital, Melbourne, Australia
| | - Claudia A Nold-Petry
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Justin M Dean
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia. .,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia.
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3
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Muraoka J, Kodama Y, Ohashi M, Goto T, Sameshima H. Intrapartum fetal heart rate patterns and perinatal outcome in chorioamnionitis at or beyond 34 weeks of gestation. J Obstet Gynaecol Res 2021; 47:1110-1117. [PMID: 33403794 DOI: 10.1111/jog.14641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/30/2020] [Accepted: 12/17/2020] [Indexed: 11/29/2022]
Abstract
AIM To investigate intrapartum fetal heart rate (FHR) patterns in women with chorioamnionitis at or beyond 34 weeks of gestation in relation to neonatal outcome and to compare clinical and subclinical chorioamnionitis. METHODS A retrospective questionnaire survey on deliveries during 2015 was conducted by the Perinatology Committee of the Japan Society of Obstetrics and Gynecology from 2016 to 2018. A total of 498 singleton births complicated by chorioamnionitis delivered at ≥34 weeks of gestation without major congenital malformations were included. The subjects were divided into clinical and subclinical chorioamnionitis groups based on Lencki's criteria. Poor perinatal outcome was defined as death or brain damage. We analyzed clinical features, FHR patterns in the last 2 h before delivery, gestational age, birthweight, Apgar score, umbilical arterial blood gas analysis, and infant's outcome. RESULTS Incidence of chorioamnionitis at ≥34 weeks of gestation was 0.59% (522/87827). Clinical and subclinical chorioamnionitis comprised 240 and 258 cases, respectively. Abnormal FHR patterns (late deceleration or decreased baseline variability) were significantly associated with poor perinatal outcome. Combined late deceleration and decreased variability showed low positive predictive value (12.8%) and high negative predictive value (99.5%), and was significantly associated with long-term poor outcome in clinical chorioamnionitis only (odds ratio: 29.4, p < 0.01). Poor perinatal outcome showed no significant difference between the clinical and subclinical chorioamnionitis groups. CONCLUSIONS Combined late deceleration and decreased variability could predict poor perinatal outcome in clinical chorioamnionitis. Poor perinatal outcome occurred in infants born to mothers with clinical and subclinical chorioamnionitis.
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Affiliation(s)
- Junsuke Muraoka
- Department of Obstetrics and Gynecology and Center for Perinatal Medicine, University of Miyazaki, Miyazaki, Japan
| | - Yuki Kodama
- Department of Obstetrics and Gynecology and Center for Perinatal Medicine, University of Miyazaki, Miyazaki, Japan
| | - Masanao Ohashi
- Department of Obstetrics and Gynecology, Miyazaki Medical Association Hospital, Miyazaki, Japan
| | - Tomoko Goto
- Department of Obstetrics and Gynecology and Center for Perinatal Medicine, University of Miyazaki, Miyazaki, Japan
| | - Hiroshi Sameshima
- Department of Obstetrics and Gynecology and Center for Perinatal Medicine, University of Miyazaki, Miyazaki, Japan
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Galinsky R, van de Looij Y, Mitchell N, Dean JM, Dhillon SK, Yamaguchi K, Lear CA, Wassink G, Davidson JO, Nott F, Zahra VA, Kelly SB, King VJ, Sizonenko SV, Bennet L, Gunn AJ. Magnetic Resonance Imaging Correlates of White Matter Gliosis and Injury in Preterm Fetal Sheep Exposed to Progressive Systemic Inflammation. Int J Mol Sci 2020; 21:ijms21238891. [PMID: 33255257 PMCID: PMC7727662 DOI: 10.3390/ijms21238891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
Progressive fetal infection/inflammation is strongly associated with neural injury after preterm birth. We aimed to test the hypotheses that progressively developing fetal inflammation leads to neuroinflammation and impaired white matter development and that the histopathological changes can be detected using high-field diffusion tensor magnetic resonance imaging (MRI). Chronically instrumented preterm fetal sheep at 0.7 of gestation were randomly assigned to receive intravenous saline (control; n = 6) or a progressive infusion of lipopolysaccharide (LPS, 200 ng intravenous over 24 h then doubled every 24 h for 5 days to induce fetal inflammation, n = 7). Sheep were killed 10 days after starting the infusions, for histology and high-field diffusion tensor MRI. Progressive LPS infusion was associated with increased circulating interleukin (IL)-6 concentrations and moderate increases in carotid artery perfusion and the frequency of electroencephalogram (EEG) activity (p < 0.05 vs. control). In the periventricular white matter, fractional anisotropy (FA) was increased, and orientation dispersion index (ODI) was reduced (p < 0.05 vs. control for both). Histologically, in the same brain region, LPS infusion increased microglial activation and astrocyte numbers and reduced the total number of oligodendrocytes with no change in myelination or numbers of immature/mature oligodendrocytes. Numbers of astrocytes in the periventricular white matter were correlated with increased FA and reduced ODI signal intensities. Astrocyte coherence was associated with increased FA. Moderate astrogliosis, but not loss of total oligodendrocytes, after progressive fetal inflammation can be detected with high-field diffusion tensor MRI.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria 3800, Australia
| | - Yohan van de Looij
- Division of Child Development & Growth, Department of Pediatrics, Gynaecology & Obstetrics, School of Medicine, University of Geneva, 1015 Geneva, Switzerland; (Y.v.d.L.); (S.V.S.)
| | - Natasha Mitchell
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Justin M. Dean
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Simerdeep K. Dhillon
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Kyohei Yamaguchi
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Christopher A. Lear
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Guido Wassink
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Joanne O. Davidson
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Fraser Nott
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
| | - Valerie A. Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
| | - Sharmony B. Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria 3800, Australia
| | - Victoria J. King
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Stéphane V. Sizonenko
- Division of Child Development & Growth, Department of Pediatrics, Gynaecology & Obstetrics, School of Medicine, University of Geneva, 1015 Geneva, Switzerland; (Y.v.d.L.); (S.V.S.)
| | - Laura Bennet
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Alistair J. Gunn
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
- Correspondence:
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5
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Gilles FH, Leviton A. Neonatal white matter damage and the fetal inflammatory response. Semin Fetal Neonatal Med 2020; 25:101111. [PMID: 32299712 DOI: 10.1016/j.siny.2020.101111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In 1962 a long-recognized pathologic abnormality in neonatal brains characterized by multiple telencephalic focal white matter necroses was renamed periventricular leukomalacia (PVL) and the authors inappropriately asserted that their entity was caused by anoxia. They also failed to include three other white matter histologic abnormalities. In this essay, we identify the breadth of white matter pathology, especially in very preterm newborns, and show that none of the four histologic expressions of white matter damage, including focal necrosis, are associated with hypoxemia or correlates as hypotension, but are instead associated with markers of fetal or perinatal inflammation, particularly in preterm babies. We begin with the background needed to evaluate the evidence.
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Affiliation(s)
- F H Gilles
- Children's Hospital Los Angeles, The University of Southern California, USA.
| | - A Leviton
- Boston Children's Hospital, Harvard Medical School, USA.
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6
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Galinsky R, Dhillon SK, Dean JM, Davidson JO, Lear CA, Wassink G, Nott F, Kelly SB, Fraser M, Yuill C, Bennet L, Gunn AJ. Tumor necrosis factor inhibition attenuates white matter gliosis after systemic inflammation in preterm fetal sheep. J Neuroinflammation 2020; 17:92. [PMID: 32293473 PMCID: PMC7087378 DOI: 10.1186/s12974-020-01769-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 03/09/2020] [Indexed: 12/21/2022] Open
Abstract
Background Increased circulating levels of tumor necrosis factor (TNF) are associated with greater risk of impaired neurodevelopment after preterm birth. In this study, we tested the hypothesis that systemic TNF inhibition, using the soluble TNF receptor Etanercept, would attenuate neuroinflammation in preterm fetal sheep exposed to lipopolysaccharide (LPS). Methods Chronically instrumented preterm fetal sheep at 0.7 of gestation were randomly assigned to receive saline (control; n = 7), LPS infusion (100 ng/kg i.v. over 24 h then 250 ng/kg/24 h for 96 h plus 1 μg LPS boluses at 48, 72, and 96 h, to induce inflammation; n = 8) or LPS plus two i.v. infusions of Etanercept (2 doses, 5 mg/kg infused over 30 min, 48 h apart) started immediately before LPS-exposure (n = 8). Sheep were killed 10 days after starting infusions, for histology. Results LPS boluses were associated with increased circulating TNF, interleukin (IL)-6 and IL-10, electroencephalogram (EEG) suppression, hypotension, tachycardia, and increased carotid artery perfusion (P < 0.05 vs. control). In the periventricular and intragyral white matter, LPS exposure increased gliosis, TNF-positive cells, total oligodendrocytes, and cell proliferation (P < 0.05 vs control), but did not affect myelin expression or numbers of neurons in the cortex and subcortical regions. Etanercept delayed the rise in circulating IL-6, prolonged the increase in IL-10 (P < 0.05 vs. LPS), and attenuated EEG suppression, hypotension, and tachycardia after LPS boluses. Histologically, Etanercept normalized LPS-induced gliosis, and increase in TNF-positive cells, proliferation, and total oligodendrocytes. Conclusion TNF inhibition markedly attenuated white matter gliosis but did not affect mature oligodendrocytes after prolonged systemic inflammation in preterm fetal sheep. Further studies of long-term brain maturation are now needed.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Simerdeep K Dhillon
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Justin M Dean
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Joanne O Davidson
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Christopher A Lear
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Guido Wassink
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Fraser Nott
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Sharmony B Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Mhoyra Fraser
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Caroline Yuill
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Laura Bennet
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Alistair Jan Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand.
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7
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Feng SYS, Hollis JH, Samarasinghe T, Phillips DJ, Rao S, Yu VYH, Walker AM. Endotoxin-induced cerebral pathophysiology: differences between fetus and newborn. Physiol Rep 2019; 7:e13973. [PMID: 30785235 PMCID: PMC6381816 DOI: 10.14814/phy2.13973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/23/2018] [Accepted: 11/26/2018] [Indexed: 02/07/2023] Open
Abstract
As the comparative pathophysiology of perinatal infection in the fetus and newborn is uncertain, this study contrasted the cerebral effects of endotoxemia in conscious fetal sheep and newborn lambs. Responses to intravenous bacterial endotoxin (lipopolysaccharide, LPS) or normal saline were studied on three consecutive days in fetal sheep (LPS 1 μg/kg, n = 5; normal saline n = 5) and newborn lambs (LPS 2 μg/kg, n = 10; normal saline n = 5). Cerebro-vascular function was assessed by monitoring cerebral blood flow (CBF) and cerebral vascular resistance (CVR) over 12 h each day, and inflammatory responses were assessed by plasma TNF alpha (TNF-α), nitrate and nitrite concentrations. Brain injury was quantified by counting both resting and active macrophages in the caudate nucleus and periventricular white matter (PVWM). An acute cerebral vasoconstriction (within 1 h of LPS injection) occurred in both the fetus (ΔCVR +53%) and newborn (ΔCVR +63%); subsequently prolonged cerebral vasodilatation occurred in the fetus (ΔCVR -33%) in association with double plasma nitrate/nitrite concentrations, but not in the newborn. Abundant infiltration of activated macrophages was observed in both CN and PVWM at each age, with the extent being 2-3 times greater in the fetus (P < 0.001). In conclusion, while the fetus and newborn experience a similar acute disruption of the cerebral circulation after LPS, the fetus suffers a more prolonged circulatory disruption, a greater infiltration of activated macrophages, and an exaggerated susceptibility to brain injury.
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Affiliation(s)
- Susan Y. S. Feng
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Neonatal DirectorateKing Edward Memorial HospitalPerth Children's HospitalSubiacoWestern AustraliaAustralia
| | - Jacob H. Hollis
- Department of PhysiologyMonash UniversityClaytonVictoriaAustralia
| | | | - David J. Phillips
- Academic & Medical PortfolioEpworth HealthCareRichmondVictoriaAustralia
| | - Shripada Rao
- Neonatal DirectorateKing Edward Memorial HospitalPerth Children's HospitalSubiacoWestern AustraliaAustralia
| | - Victor Y. H. Yu
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Monash NewbornMonash Medical CentreClaytonVictoriaAustralia
| | - Adrian M. Walker
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
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8
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Dean JM, Shi Z, Fleiss B, Gunn KC, Groenendaal F, van Bel F, Derrick M, Juul SE, Tan S, Gressens P, Mallard C, Bennet L, Gunn AJ. A Critical Review of Models of Perinatal Infection. Dev Neurosci 2015; 37:289-304. [DOI: 10.1159/000370309] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/02/2014] [Indexed: 11/19/2022] Open
Abstract
One of the central, unanswered questions in perinatology is why preterm infants continue to have such poor long-term neurodevelopmental, cognitive and learning outcomes, even though severe brain injury is now rare. There is now strong clinical evidence that one factor underlying disability may be infection, as well as nonspecific inflammation, during fetal and early postnatal life. In this review, we examine the experimental evidence linking both acute and chronic infection/inflammation with perinatal brain injury and consider key experimental determinants, including the microglia response, relative brain and immune maturity and the pattern of exposure to infection. We highlight the importance of the origin and derivation of the bacterial cell wall component lipopolysaccharide. Such experimental paradigms are essential to determine the precise time course of the inflammatory reaction and to design targeted neuroprotective strategies to protect the perinatal brain from infection and inflammation.
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9
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Barton SK, Moss TJM, Hooper SB, Crossley KJ, Gill AW, Kluckow M, Zahra V, Wong FY, Pichler G, Galinsky R, Miller SL, Tolcos M, Polglase GR. Protective ventilation of preterm lambs exposed to acute chorioamnionitis does not reduce ventilation-induced lung or brain injury. PLoS One 2014; 9:e112402. [PMID: 25379714 PMCID: PMC4224447 DOI: 10.1371/journal.pone.0112402] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 10/15/2014] [Indexed: 01/25/2023] Open
Abstract
Background The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (VT) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high VT ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response. Methods Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPSUVC; n = 6), or were ventilated using an injurious high VT strategy (LPSINJ; n = 5) or a protective ventilation strategy (LPSPROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury. Results LPSINJ lambs had poorer oxygenation than LPSPROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPSINJ and LPSPROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (p<0.02) and cell death (p<0.05) in the WM, which were equivalent in magnitude between groups. Conclusions Ventilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor to WM injury in infants exposed to chorioamnionitis.
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Affiliation(s)
- Samantha K. Barton
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Timothy J. M. Moss
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
| | - Stuart B. Hooper
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
| | - Kelly J. Crossley
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Andrew W. Gill
- School of Women's and Infants' Health, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Martin Kluckow
- Department of Neonatal Medicine, Royal North Shore Hospital and University of Sydney, Sydney, New South Wales, 2065, Australia
| | - Valerie Zahra
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Flora Y. Wong
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Gerhard Pichler
- Department of Pediatrics, Medical University Graz, Auenbruggerplatz 30, Graz, Austria, 8036
| | - Robert Galinsky
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Suzanne L. Miller
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
| | - Mary Tolcos
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Graeme R. Polglase
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
- * E-mail:
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10
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Lear CA, Davidson JO, Booth LC, Wassink G, Galinsky R, Drury PP, Fraser M, Bennet L, Gunn AJ. Biphasic changes in fetal heart rate variability in preterm fetal sheep developing hypotension after acute on chronic lipopolysaccharide exposure. Am J Physiol Regul Integr Comp Physiol 2014; 307:R387-95. [PMID: 24944248 DOI: 10.1152/ajpregu.00110.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Perinatal exposure to infection is highly associated with adverse outcomes. Experimentally, acute, severe exposure to gram-negative bacterial lipopolysaccharide (LPS) is associated with increased fetal heart rate variability (FHRV). It is unknown whether FHRV is affected by subclinical infection with or without acute exacerbations. We therefore tested the hypothesis that FHRV would be associated with hypotension after acute on chronic exposure to LPS. Chronically instrumented fetal sheep at 0.7 gestation were exposed to a continuous low-dose LPS infusion (n = 12, 100 ng/kg over 24 h, followed by 250 ng·kg(-1)·24 h(-1) for a further 96 h) or the same volume of saline (n = 10). Boluses of either 1 μg LPS or saline were given at 48, 72, and 96 h. Low-dose infusion was not associated with hemodynamic or FHRV changes. The first LPS bolus was associated with tachycardia and suppression of nuchal electromyographic activity in all fetuses. Seven of twelve fetuses developed hypotension (a fall in mean arterial blood pressure ≥5 mmHg). FHRV was transiently increased only at the onset of hypotension, in association with increased cytokine induction and electroencephalogram suppression. FHRV then fell before the nadir of hypotension, with transient suppression of short-term FHRV. After the second LPS bolus, the hypotension group showed a biphasic pattern of a transient increase in FHRV followed by more prolonged suppression. These findings suggest that infection-related hypotension in the preterm fetus mediates the transient increase in FHRV and that repeated exposure to LPS leads to progressive loss of FHRV.
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Affiliation(s)
| | | | | | | | | | | | - Mhoyra Fraser
- Department of Physiology, and The Liggins Institute, University of Auckland, Auckland, New Zealand
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11
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Chau V, McFadden DE, Poskitt KJ, Miller SP. Chorioamnionitis in the pathogenesis of brain injury in preterm infants. Clin Perinatol 2014; 41:83-103. [PMID: 24524448 DOI: 10.1016/j.clp.2013.10.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chorioamnionitis (or placental infection) is suspected to be a risk factor for brain injury in premature infants. The suggested association between chorioamnionitis and cystic periventricular leukomalacia and cerebral palsy is uncertain because of the variability of study designs and definitions of chorioamnionitis. Improvements in neonatal intensive care may have attenuated the impact of chorioamnionitis on brain health outcomes. Large multicenter studies using rigorous definitions of chorioamnionitis on placental pathologies and quantitative magnetic resonance techniques may offer the optimal way to clarify the complex role of chorioamnionitis in modifying brain health and long-term outcomes.
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Affiliation(s)
- Vann Chau
- Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada; University of Toronto, Department of Pediatrics, 563 Spadina Crescent, Toronto, Ontario, M5S 2J7, Canada; Child & Family Research Institute, 950 28th Avenue, Vancouver, British Columbia, V5Z 4H4, Canada.
| | - Deborah E McFadden
- Child & Family Research Institute, 950 28th Avenue, Vancouver, British Columbia, V5Z 4H4, Canada; Department of Pathology, BC Children's & Women's Health Center, 4480 Oak Street, Vancouver, British Columbia, V6H 3V4, Canada; University of British Columbia, Departments of Pediatrics, Pathology and Radiology, 2329 West Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Kenneth J Poskitt
- Child & Family Research Institute, 950 28th Avenue, Vancouver, British Columbia, V5Z 4H4, Canada; University of British Columbia, Departments of Pediatrics, Pathology and Radiology, 2329 West Mall, Vancouver, British Columbia, V6T 1Z4, Canada; Departments of Pediatrics and Radiology, BC Children's & Women's Health Center, 4480 Oak Street, Vancouver, British Columbia, V6H 3V4, Canada
| | - Steven P Miller
- Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada; Neurosciences and Mental Health Program, Research Institute, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada; University of Toronto, Department of Pediatrics, 563 Spadina Crescent, Toronto, Ontario, M5S 2J7, Canada; Child & Family Research Institute, 950 28th Avenue, Vancouver, British Columbia, V5Z 4H4, Canada
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12
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Bennet L, Van Den Heuij L, M Dean J, Drury P, Wassink G, Jan Gunn A. Neural plasticity and the Kennard principle: does it work for the preterm brain? Clin Exp Pharmacol Physiol 2013; 40:774-84. [DOI: 10.1111/1440-1681.12135] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/29/2013] [Accepted: 05/31/2013] [Indexed: 12/27/2022]
Affiliation(s)
- Laura Bennet
- Fetal Physiology and Neuroscience Groups; Department of Physiology; University of Auckland; Auckland New Zealand
| | - Lotte Van Den Heuij
- Fetal Physiology and Neuroscience Groups; Department of Physiology; University of Auckland; Auckland New Zealand
| | - Justin M Dean
- Fetal Physiology and Neuroscience Groups; Department of Physiology; University of Auckland; Auckland New Zealand
| | - Paul Drury
- Fetal Physiology and Neuroscience Groups; Department of Physiology; University of Auckland; Auckland New Zealand
| | - Guido Wassink
- Fetal Physiology and Neuroscience Groups; Department of Physiology; University of Auckland; Auckland New Zealand
| | - Alistair Jan Gunn
- Fetal Physiology and Neuroscience Groups; Department of Physiology; University of Auckland; Auckland New Zealand
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13
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Galinsky R, Hooper SB, Polglase GR, Moss TJM. Intrauterine inflammation alters fetal cardiopulmonary and cerebral haemodynamics in sheep. J Physiol 2013; 591:5061-70. [PMID: 23878364 DOI: 10.1113/jphysiol.2013.259119] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Intrauterine inflammation impairs fetal pulmonary vascular development and increases cerebral metabolic rate in fetal sheep. We hypothesized that these structural and metabolic effects of intrauterine inflammation would be accompanied by reduced fetal pulmonary blood flow and increased cerebral perfusion. Fetal sheep were instrumented at 112 days of gestation (term is 147 days) for measurement of cardiopulmonary and cerebral haemodynamics. At 118 days ewes were randomly assigned to receive intra-amniotic lipopolysaccharide (LPS, 20 mg from Escherichia coli; n = 7) or saline (control, 4 ml; n = 6). Fetal haemodynamic data were recorded continually from 1 h before intra-amniotic LPS or saline, until 144 h after. Fetal arterial blood was sampled before, and periodically after, intra-amniotic LPS or saline. End-diastolic and mean pulmonary blood flows were significantly lower than control from 48 and 96 h after LPS exposure, respectively, until the end of the experiment. Carotid blood flow was transiently increased at 96 and 120 h after LPS exposure. Carotid arterial oxygen content was lower than control from 48 h after intra-amniotic LPS. Fetal arterial lactate concentration was higher than control between 4 and 12 h after intra-amniotic LPS. Experimental intrauterine inflammation reduces pulmonary blood flow in fetal sheep, over a time course consistent with impaired pulmonary vascular development. Increased carotid blood flow after LPS administration may reflect an inflammation-induced increase in cerebral metabolic demand.
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Affiliation(s)
- Robert Galinsky
- R. Galinsky: The Ritchie Centre, Monash Institute of Medical Research, PO Box 5418, Clayton, Victoria 3168, Australia.
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14
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Gisslen T, Hillman NH, Musk GC, Kemp MW, Kramer BW, Senthamaraikannan P, Newnham JP, Jobe AH, Kallapur SG. Repeated exposure to intra-amniotic LPS partially protects against adverse effects of intravenous LPS in preterm lambs. Innate Immun 2013; 20:214-24. [PMID: 23751819 DOI: 10.1177/1753425913488430] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Histologic chorioamnionitis, frequently associated with preterm births and adverse outcomes, results in prolonged exposure of preterm fetuses to infectious agents and pro-inflammatory mediators, such as LPS. Endotoxin tolerance-type effects were demonstrated in fetal sheep following repetitive systemic or intra-amniotic (i.a.) exposures to LPS, suggesting that i.a. LPS exposure would cause endotoxin tolerance to a postnatal systemic dose of LPS in preterm sheep. In this study, randomized pregnant ewes received either two i.a. injections of LPS or saline prior to preterm delivery. Following operative delivery, the lambs were treated with surfactant, ventilated, and randomized to receive either i.v. LPS or saline at 30 min of age. Physiologic variables and indicators of systemic and lung inflammation were measured. Intravenous LPS decreased blood neutrophils and platelets values following i.a. saline compared to that after i.a. LPS. Intra-amniotic LPS prevented blood pressure from decreasing following the i.v. LPS, but also caused an increased oxygen index. Intra-amniotic LPS did not cause endotoxin tolerance as assessed by cytokine expression in the liver, lung or plasma, but increased myeloperoxidase-positive cells in the lung. The different compartments of exposure to LPS (i.a. vs i.v.) are unique to the fetal to newborn transition. Intra-amniotic LPS incompletely tolerized fetal lambs to postnatal i.v. LPS.
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Affiliation(s)
- Tate Gisslen
- 1Division of Neonatology/Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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15
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Booth LC, Drury PP, Muir C, Jensen EC, Gunn AJ, Bennet L. Acute on chronic exposure to endotoxin is associated with enhanced chemoreflex responses in preterm fetal sheep. Am J Physiol Regul Integr Comp Physiol 2013; 304:R799-803. [DOI: 10.1152/ajpregu.00005.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is increasing evidence that exposure to infection can sensitize the fetus to subsequent hypoxic injury. However, it is unclear whether this involves compromise of the fetal cardiovascular adaptation to acute asphyxia. Chronically instrumented 103-day-old (0.7 gestational age, term is 147 days) fetal sheep in utero were randomized to receive either gram-negative lipopolysaccharide (LPS) as a continuous low-dose infusion for 120 h plus boluses of 1 μg LPS at 48, 72, and 96 h with asphyxia at 102 h (i.e., 6 h after the final LPS bolus) induced by umbilical cord occlusion for 15 min (LPS treated, n = 8), or the same volume of saline plus occlusion (saline treated, n = 7). Fetuses were killed 5 days after occlusion. LPS was associated with a more rapid fall in fetal heart rate at the onset of occlusion ( P < 0.05) and with minimally lower values during occlusion ( P < 0.05). The LPS-treated fetuses had lower fetal mean arterial blood pressure (BP) and greater carotid artery blood flow (CaBF) before occlusion ( P < 0.05) but showed an increase in BP and fall in CaBF to similar values as saline controls during occlusion. There were no differences between the groups in femoral blood flow before or during occlusion. Contrary to our initial hypothesis, acute on chronic exposure to LPS was associated with more rapid cardiovascular adaptation to umbilical cord occlusion.
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Affiliation(s)
- Lindsea C. Booth
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Paul P. Drury
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Cameron Muir
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Ellen C. Jensen
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J. Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
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16
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Mathai S, Booth LC, Davidson JO, Drury PP, Fraser M, Jensen EC, George S, Naylor A, Gunn AJ, Bennet L. Acute on chronic exposure to endotoxin in preterm fetal sheep. Am J Physiol Regul Integr Comp Physiol 2012; 304:R189-97. [PMID: 23235324 DOI: 10.1152/ajpregu.00388.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Acute, high-dose exposure to endotoxin lipopolysaccharide (LPS) in preterm fetal sheep can trigger periventricular white matter lesions (PVL), in association with severe hypotension/hypoxemia and significant mortality. Intriguingly, however, chronic or repeated exposure to LPS can induce tachyphylaxis. We therefore tested the hypothesis that progressive, acute on chronic fetal infection would be associated with white matter injury with little fetal mortality. Chronically instrumented preterm (0.7 gestational age) fetal sheep were exposed to a continuous low-dose LPS infusion (100 ng over 24 h, followed by 250 ng/24 h for 96 h) or saline. Boluses of 1 μg LPS or saline were given at 48, 72, and 96 h; sheep were killed at day 10. Six of 11 fetal sheep exposed to saline infusion + LPS boluses died 4-7 h after the first bolus. In contrast, there was no fetal mortality after saline infusions alone (n = 9), low-dose LPS infusion + saline boluses (n = 5), or low-dose LPS + LPS boluses (n = 9). Low-dose LPS infusion + LPS boluses was associated with greater microglial induction than low-dose LPS + saline boluses but a similar area of periventricular white matter inflammation. One fetus developed severe focal white matter necrosis after LPS infusion + boluses. The acute cardiovascular compromise associated with high-dose, acute exposure to LPS is markedly attenuated by previous low-dose infusions, with limited apparent exacerbation of periventricular white matter injury compared with low-dose infusion alone.
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Affiliation(s)
- Sam Mathai
- Department of Physiology, the University of Auckland, New Zealand
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17
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Strackx E, Gantert M, Moers V, van Kooten IAJ, Rieke R, Hürter H, Lemmens MAM, Steinbusch HWM, Zimmermann LJI, Vles JSH, Garnier Y, Gavilanes AWD, Kramer BW. Increased number of cerebellar granule cells and astrocytes in the internal granule layer in sheep following prenatal intra-amniotic injection of lipopolysaccharide. THE CEREBELLUM 2012; 11:132-44. [PMID: 21773814 PMCID: PMC3311858 DOI: 10.1007/s12311-011-0297-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chorioamnionitis is an important problem in perinatology today, leading to brain injury and neurological handicaps. However, there are almost no data available regarding chorioamnionitis and a specific damage of the cerebellum. Therefore, this study aimed at determining if chorioamnionitis causes cerebellar morphological alterations. Chorioamnionitis was induced in sheep by the intra-amniotic injection of lipopolysaccharide (LPS) at a gestational age (GA) of 110 days. At a GA of 140 days, we assessed the mean total and layer-specific volume and the mean total granule cell (GCs) and Purkinje cell (PC) number in the cerebelli of LPS-exposed and control animals using high-precision design-based stereology. Astrogliosis was assessed in the gray and white matter (WM) using a glial fibrillary acidic protein staining combined with gray value image analysis. The present study showed an unchanged volume of the total cerebellum as well as the molecular layer, outer and inner granular cell layers (OGL and IGL, respectively), and WM. Interestingly, compared with controls, the LPS-exposed brains showed a statistically significant increase (+20.4%) in the mean total number of GCs, whereas the number of PCs did not show any difference between the two groups. In addition, LPS-exposed animals showed signs of astrogliosis specifically affecting the IGL. Intra-amniotic injection of LPS causes morphological changes in the cerebellum of fetal sheep still detectable at full-term birth. In this study, changes were restricted to the inner granule layer. These cerebellar changes might correspond to some of the motor or non-motor deficits seen in neonates from compromised pregnancies.
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Affiliation(s)
- Eveline Strackx
- Department of Neuroscience and European Graduate School of Neuroscience, Maastricht University, Maastricht, The Netherlands
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18
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Bennet L, Booth LC, Drury PP, Quaedackers JSL, Gunn AJ. Preterm neonatal cardiovascular instability: Does understanding the fetus help evaluate the newborn? Clin Exp Pharmacol Physiol 2012; 39:965-72. [DOI: 10.1111/j.1440-1681.2012.05744.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Laura Bennet
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
| | - Lindsea C Booth
- Neurobiology Division; Florey Neuroscience Institutes; University of Melbourne; Melbourne; Victoria; Australia
| | - Paul P Drury
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
| | - Josine SL Quaedackers
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
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19
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Cerebral autoregulation in the first day after preterm birth: no evidence of association with systemic inflammation. Pediatr Res 2012; 71:253-60. [PMID: 22278187 DOI: 10.1038/pr.2011.46] [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: 11/08/2022]
Abstract
INTRODUCTION Both systemic inflammation and impaired cerebral autoregulation (CA) have been associated with brain injury in preterm infants. We hypothesized that impaired CA represents a hemodynamic link between inflammation and brain injury. RESULTS Neither fetal vasculitis nor interleukin-6 (IL-6) affected CA significantly. A high level of IL-6 was associated with hypotension (P = 0.03) irrespective of dopamine therapy. The magnitude of impairment in CA increased with decreasing mean arterial blood pressure (MAP) (P = 0.02). No significant associations were found between these parameters and either intraventricular hemorrhage (IVH) (n = 10) or neonatal mortality (n = 8). DISCUSSION In conclusion, postnatal inflammation was weakly associated with arterial hypotension, and hypotension was weakly associated with impaired autoregulation. There was no direct association, however, between autoregulation and antenatal or postnatal signs of inflammation. METHODS In our study, 60 infants (mean (±SD) of gestational age (GA) 27 (±1.3) wk) underwent continuous recording of MAP and cerebral oxygenation index (OI) by means of near-infrared spectroscopy (NIRS) for 2.3 ± 0.5 h, starting 18 ± 9 h after birth. Coherence and transfer function gain between MAP and OI represented the presence and degree of impairment of CA, respectively. We considered fetal vasculitis (placenta histology) to be an antenatal marker of inflammation, and used the level of IL-6 in blood, measured at 18 ± 10 h after birth, as a postnatal marker of inflammation. Definition of hypotension was MAP (mm Hg) ≤ GA (wk).
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20
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Dean JM, van de Looij Y, Sizonenko SV, Lodygensky GA, Lazeyras F, Bolouri H, Kjellmer I, Huppi PS, Hagberg H, Mallard C. Delayed cortical impairment following lipopolysaccharide exposure in preterm fetal sheep. Ann Neurol 2011; 70:846-56. [PMID: 22002627 DOI: 10.1002/ana.22480] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 04/28/2011] [Accepted: 05/06/2011] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Preterm infants exhibit chronic deficits in white matter (WM) and cortical maturation. Although fetal infection/inflammation may contribute to WM pathology, the factors contributing to cortical changes are largely unknown. We examined the effect of fetal lipopolysaccharide (LPS) exposure on WM and cortical development as assessed by magnetic resonance imaging (MRI), electroencephalography (EEG), and histopathology in fetal sheep at preterm human equivalent age. METHODS LPS was administered to fetal sheep at 102.5 ± 0.5 days of gestation. Continuous biophysical recordings were analyzed for 10 days after LPS. At postmortem, measurement of cerebral WM and cortical tissue volumes was achieved by stereological techniques. Specific effects of LPS on MRI-assessed T(1)-weighted and T(2)-weighted images, and immunohistochemical expression of oligodendrocytes, proliferating cells, cortical NeuN-positive and Nurr1-positive neurons (subplate marker), and cell death mechanisms were examined. RESULTS We observed reductions in WM (~21%; LPS, 1.19 ± 0.04 vs control, 1.51 ± 0.07 cm(3); p < 0.001) and cortical (~18%; LPS, 2.34 ± 0.10 vs control, 2.85 ± 0.07 cm(3); p < 0.001) volumes, associated with overt and diffuse WM injury, T(1)-/T(2) -weighted signal alterations, and reduced numbers of WM oligodendrocytes (LPS, 485 ± 31 vs control, 699 ± 69 cells/mm(2); p = 0.0189) and NeuN-positive (LPS, 421 ± 71 vs control 718 ± 92 cells/mm(2); p = 0.04) and Nurr1-positive (control, 2.5 ± 0.6 vs LPS, 0.6 ± 0.1 cells/mm(2); p = 0.007) cortical neurons after LPS. Moreover, there was loss of the normal maturational increase in cortical EEG amplitude, which correlated with reduced cortical volumes. INTERPRETATION Fetal exposure to LPS prior to myelination onset can impair both white matter and cortical development in a preclinical large animal model, supporting a role for maternal/fetal infection in the pathogenesis of preterm brain injury.
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Affiliation(s)
- Justin M Dean
- Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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21
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Abstract
The bacterial infection of chorion and amnion is a common finding in premature delivery and is referred to as chorioamnionitis. As the mother rarely shows symptoms of a systemic inflammation, the course of chorioamnionitis is frequently asymptomatic and chronic. In contrast, the fetal inflammatory response syndrome represents a separate phenomenon, including umbilical inflammation and increased serum levels of proinflammatory cytokines in the fetus. Ascending maternal infections frequently lead to systemic fetal inflammatory reaction. Clinical studies have shown that antenatal exposure to inflammation puts the extremely immature neonates at a high risk for worsening pulmonary, neurological and other organ development. Interestingly, the presence of chorioamnionitis is associated with a lower rate of neonatal mortality in extremely immature newborns. In the following review, the pathogeneses of inflammation-associated perinatal morbidity are outlined. The concept of fetal multiorganic disease during intrauterine infection is introduced and discussed.
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22
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Bennet L, Cowie RV, Stone PR, Barrett R, Naylor AS, Blood AB, Gunn AJ. The neural and vascular effects of killed Su-Streptococcus pyogenes (OK-432) in preterm fetal sheep. Am J Physiol Regul Integr Comp Physiol 2010; 299:R664-72. [PMID: 20484698 DOI: 10.1152/ajpregu.00116.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fetal exposure to inflammatory mediators is associated with a greater risk of brain injury and may cause endothelial dysfunction; however, nearly all the evidence is derived from gram-negative bacteria. Intrapleural injections of OK-432, a killed Su-strain of Streptococcus pyogenes, has been used to treat fetal chylothorax. In this study, we evaluated the neural and cardiovascular effects of OK-432 in preterm fetal sheep (104 +/- 1 days, term 147 days). OK-432 (0.1 mg, n = 6) or saline vehicle (n = 7) was infused in the fetal pleura, and fetuses were monitored for 7 days. Blood samples were taken routinely for plasma nitrite measurement. Fetal brains were taken for histological assessment at the end of the experiment. Between 3 and 7 h postinjection, OK-432 administration was associated with transient suppression of fetal body and breathing movements and electtroencephalogram activity (P < 0.05), increased carotid and femoral vascular resistance (P < 0.05), but no change in blood pressure. Brain activity and behavior then returned to normal except in one fetus that developed seizures. OK-432 fetuses showed progressive, sustained vasodilatation (P < 0.05), with lower blood pressure after 4 days (P < 0.05), but normal heart rate. There were no changes in plasma nitrite levels. Histological studies showed bilateral infarction in the dorsal limb of the hippocampus of the fetus that developed seizures, but no injury in other fetuses. We conclude that a single low-dose injection of OK-432 can be associated with risk of focal cerebral injury in the preterm fetus and chronic central and peripheral vasodilatation that does not appear to be mediated by nitric oxide.
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Affiliation(s)
- L Bennet
- Department of Physiology, The University of Auckland, New Zealand.
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Feng SYS, Samarasinghe T, Phillips DJ, Alexiou T, Hollis JH, Yu VYH, Walker AM. Acute and chronic effects of endotoxin on cerebral circulation in lambs. Am J Physiol Regul Integr Comp Physiol 2010; 298:R760-6. [DOI: 10.1152/ajpregu.00398.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The impact of endotoxemia on cerebral endothelium and cerebral blood flow (CBF) regulation was studied in conscious newborn lambs. Bacterial endotoxin [LPS, 2 μg/kg iv] was infused on 3 consecutive days. Cerebrovascular function was assessed by monitoring CBF and cerebral vascular resistance (CVR) over 12 h each day and by the endothelium-dependent vasodilator bradykinin (BK) ( n = 10). Inflammatory responses were assessed by plasma tumor necrosis factor-α (TNF-α, n = 5). Acutely, LPS disrupted the cerebral circulation within 1 h, with peak cerebral vasoconstriction at 3 h (CBF −28 and CVR +118%, P < 0.05) followed by recovery to baseline by 12 h. TNF-α and body temperature peaked ∼1 h post-LPS. BK-induced vasodilatation (CVR −20%, P < 0.05) declined with each LPS infusion, was abolished after 3 days, and remained absent for at least the subsequent 5 days. Histological evidence of brain injury was found in four of five LPS-treated newborns. We conclude that endotoxin impairs cerebral perfusion in newborn lambs via two mechanisms: 1) acute vasoconstriction (over several hours); and 2) persistent endothelial dysfunction (over several days). Endotoxin-induced circulatory impairments may place the newborn brain at prolonged risk of CBF dysregulation and injury as a legacy of endotoxin exposure.
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Affiliation(s)
- Susan Y. S. Feng
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University
| | - Thilini Samarasinghe
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University
| | - David J. Phillips
- Centre of Reproduction and Development, Monash Institute of Medical Research, Monash University; and
| | - Theodora Alexiou
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University
| | - Jacob H. Hollis
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Victor Y. H. Yu
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University
- Newborn Services, Monash Medical Centre
| | - Adrian M. Walker
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University
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Grintzalis K, Papapostolou I, Assimakopoulos SF, Mavrakis A, Faropoulos K, Karageorgos N, Georgiou C, Chroni E, Konstantinou D. Time-related alterations of superoxide radical levels in diverse organs of bile duct-ligated rats. Free Radic Res 2009; 43:803-8. [PMID: 19548155 DOI: 10.1080/10715760903062903] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The time-related alterations of superoxide radical measured in vivo by employing an ultrasensitive fluorescent assay in the liver, intestine, kidney and brain of rats with experimentally induced obstructive jaundice was investigated. Eighteen rats were randomly divided into Group A, rats subjected to sham operation, and Group B, rats subjected to bile duct ligation (BDL). Three rats from each group were subsequently killed at different time points post-operatively (1, 5 and 10 days). As compared to sham-operated, BDL rats showed a gradual increase with time of superoxide radical in the intestine, liver, kidney and brain: for animals sacrificed on the 1(st), 5(th) and 10(th) day the increase was 45%, 50% and 96% in the liver, 76%, 81% and 118% in the intestine, 64%, 71% and 110% in the kidney and 76%, 95% and 142% in the brain, respectively. This study provides direct evidence of an early appearance of oxidative stress in diverse organs, implying a uniform systemic response to biliary obstruction and emphasizing the need of early bile flow restoration.
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Affiliation(s)
- Konstantinos Grintzalis
- Department of Biology, Division of Genetics, Cell and Developmental Biology, School of Medicine, University of Patras, Greece
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