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Lear CA, Maeda Y, King VJ, Dhillon SK, Beacom MJ, Gunning MI, Lear BA, Davidson JO, Stone PR, Ikeda T, Gunn AJ, Bennet L. Circadian patterns of heart rate variability in fetal sheep after hypoxia-ischaemia: A biomarker of evolving brain injury. J Physiol 2023. [PMID: 37432936 DOI: 10.1113/jp284560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 06/23/2023] [Indexed: 07/13/2023] Open
Abstract
Hypoxia-ischaemia (HI) before birth is a key risk factor for stillbirth and severe neurodevelopmental disability in survivors, including cerebral palsy, although there are no reliable biomarkers to detect at risk fetuses that may have suffered a transient period of severe HI. We investigated time and frequency domain measures of fetal heart rate variability (FHRV) for 3 weeks after HI in preterm fetal sheep at 0.7 gestation (equivalent to preterm humans) until 0.8 gestation (equivalent to term humans). We have previously shown that this is associated with delayed development of severe white and grey matter injury, including cystic white matter injury (WMI) resembling that observed in human preterm infants. HI was associated with suppression of time and frequency domain measures of FHRV and reduced their circadian rhythmicity during the first 3 days of recovery. By contrast, circadian rhythms of multiple measures of FHRV were exaggerated over the final 2 weeks of recovery, mediated by a greater reduction in FHRV during the morning nadir, but no change in the evening peak. These data suggest that the time of day at which FHRV measurements are taken affects their diagnostic utility. We further propose that circadian changes in FHRV may be a low-cost, easily applied biomarker of antenatal HI and evolving brain injury. KEY POINTS: Hypoxia-ischaemia (HI) before birth is a key risk factor for stillbirth and probably for disability in survivors, although there are no reliable biomarkers for antenatal brain injury. In preterm fetal sheep, acute HI that is known to lead to delayed development of severe white and grey matter injury over 3 weeks, was associated with early suppression of multiple time and frequency domain measures of fetal heart rate variability (FHRV) and loss of their circadian rhythms during the first 3 days after HI. Over the final 2 weeks of recovery after HI, exaggerated circadian rhythms of frequency domain FHRV measures were observed. The morning nadirs were lower with no change in the evening peak of FHRV. Circadian changes in FHRV may be a low-cost, easily applied biomarker of antenatal HI and evolving brain injury.
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Affiliation(s)
- Christopher A Lear
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Yoshiki Maeda
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
- The Department of Obstetrics and Gynaecology, Mie University, Mie, Japan
| | - Victoria J King
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Simerdeep K Dhillon
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Michael J Beacom
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Mark I Gunning
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Benjamin A Lear
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Peter R Stone
- The Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Tomoaki Ikeda
- The Department of Obstetrics and Gynaecology, Mie University, Mie, Japan
| | - Alistair J Gunn
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, Fetal Physiology and Neuroscience Group, The University of Auckland, Auckland, New Zealand
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Zhou KQ, Draghi V, Lear CA, Dean JM, Ashton JL, Hou Y, Bennet L, Gunn AJ, Davidson JO. Protection of axonal integrity with 48 or 72 h of cerebral hypothermia in near-term fetal sheep. Pediatr Res 2020; 88:48-56. [PMID: 31234193 DOI: 10.1038/s41390-019-0475-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/06/2019] [Accepted: 06/08/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Therapeutic hypothermia is partially protective for neonatal hypoxic-ischemic encephalopathy (HIE). Damage to the white matter tracts is highly associated with adverse outcomes after HIE, but the effectiveness and optimal duration of hypothermia to attenuate axonal injury are unclear. METHODS Near-term fetal sheep were randomized to sham control or cerebral ischemia for 30 min with normothermia or cerebral hypothermia from 3 to either 48 or 72 h. Sheep were killed after 7 days. SMI-312-labeled axons and myelin basic protein were quantified in the intragyral white matter of the first and second parasagittal gyri. RESULTS Ischemia was associated with reduced axonal and myelin area fraction (p < 0.05); loss of axonal and myelin linearity (p < 0.05); and thin, sparse axons, with spheroids, compared to dense, linear morphology in sham controls and associated with induction of microglia in an amoeboid morphology. Both ischemia-48 h hypothermia and ischemia-72 h hypothermia improved axonal area fraction and linearity (p < 0.05), although abnormal morphological features were seen in a subset. Microglial induction was partially suppressed by ischemia-48 h hypothermia, with a ramified morphology. CONCLUSIONS These data suggest that therapeutic hypothermia can alleviate post-ischemic axonopathy, in part by suppressing secondary inflammation.
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Affiliation(s)
- Kelly Q Zhou
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Vittoria Draghi
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Jesse L Ashton
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Yufeng Hou
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Laura Bennet
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
| | - Joanne O Davidson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Galinsky R, Lear CA, Dean JM, Wassink G, Dhillon SK, Fraser M, Davidson JO, Bennet L, Gunn AJ. Complex interactions between hypoxia-ischemia and inflammation in preterm brain injury. Dev Med Child Neurol 2018; 60:126-133. [PMID: 29194585 DOI: 10.1111/dmcn.13629] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 12/12/2022]
Abstract
UNLABELLED Children surviving preterm birth have a high risk of disability, particularly cognitive and learning problems. There is extensive clinical and experimental evidence that disability is now primarily related to dysmaturation of white and gray matter, defined by failure of oligodendrocyte maturation and neuronal dendritic arborization, rather than cell death alone. The etiology of this dysmaturation is multifactorial, with contributions from hypoxia-ischemia, infection/inflammation and barotrauma. Intriguingly, these factors can interact to both increase and decrease damage. In this review we summarize preclinical and clinical evidence that all of these factors trigger secondary or chronic inflammation and gliosis. Thus, we hypothesize that these shared pathological features play a key role in a final common pathway that leads to the impaired neural maturation and connectivity and cognitive/motor impairments that are commonly observed in infants born preterm. This raises the possibility that secondary or chronic inflammation may be a viable therapeutic target for delayed interventions to improve neurodevelopmental outcomes after preterm birth. WHAT THIS PAPER ADDS Hypoxia-ischemia, infection/inflammation, and barotrauma/volutrauma all contribute to preterm brain injury. Multiple different triggers of preterm brain injury are associated with central nervous system dysmaturation. Secondary brain inflammation may be a viable target to improve neurodevelopment after preterm birth.
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Affiliation(s)
- Robert Galinsky
- The Department of Physiology, University of Auckland, Auckland, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Christopher A Lear
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Mhoyra Fraser
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Department of Physiology, University of Auckland, Auckland, New Zealand
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Galinsky R, Davidson JO, Dean JM, Green CR, Bennet L, Gunn AJ. Glia and hemichannels: key mediators of perinatal encephalopathy. Neural Regen Res 2018; 13:181-189. [PMID: 29557357 PMCID: PMC5879879 DOI: 10.4103/1673-5374.226378] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Perinatal encephalopathy remains a major cause of disability, such as cerebral palsy. Therapeutic hypothermia is now well established to partially reduce risk of disability in late preterm/term infants. However, new and complementary therapeutic targets are needed to further improve outcomes. There is increasing evidence that glia play a key role in neural damage after hypoxia-ischemia and infection/inflammation. In this review, we discuss the role of astrocytic gap junction (connexin) hemichannels in the spread of neural injury after hypoxia-ischemia and/or infection/inflammation. Potential mechanisms of hemichannel mediated injury likely involve impaired intracellular calcium handling, loss of blood-brain barrier integrity and release of adenosine triphosphate (ATP) resulting in over-activation of purinergic receptors. We propose the hypothesis that inflammation-induced opening of connexin hemichannels is a key regulating event that initiates a vicious cycle of excessive ATP release, which in turn propagates activation of purinergic receptors on microglia and astrocytes. This suggests that developing new neuroprotective strategies for preterm infants will benefit from a detailed understanding of glial and connexin hemichannel responses.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, University of Auckland, Auckland, New Zealand; The Ritchie Centre, Hudson Institute of Medical Research, Victoria, Australia
| | - Joanne O Davidson
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, University of Auckland, Auckland, New Zealand
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Fraser M, Bennet L, Helliwell R, Wells S, Williams C, Gluckman P, Gunn AJ, Inder T. Regional Specificity of Magnetic Resonance Imaging and Histopathology Following Cerebral Ischemia in Preterm Fetal Sheep. Reprod Sci 2016; 14:182-91. [PMID: 17636230 DOI: 10.1177/1933719107299612] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Early and accurate evaluation of the nature and extent of cerebral injury in the preterm infant brain is important for prognostication and decision making in the neonatal intensive care unit. The capability of magnetic resonance imaging (MRI) to define acute ischemic changes in white and gray matter in comparison to contemporaneous histopathology has not been adequately ascertained. The aim of this study is to assess whether postmortem MRI predicts the nature and extent of brain injury in a preterm fetal sheep model of cerebral hypoperfusion. MRI examinations were performed on fetal sheep brains (d99-100 gestation), perfusion fixed 72 hours after an ischemic insult (n = 7) with left-hemispheric placement of a microdialysis probe and compared with sham-occlusion (n = 3) and unoperated-control fetuses (n = 4). Cerebral ischemia was associated with MRI changes including global cerebral injury and diffuse white matter signal abnormality, which corresponded closely with histological damage. However, histological changes in deep structures, including the corona radiata, thalamus, and globus pallidus were not reliably detected on MRI. These findings confirm that in preterm fetal sheep, MRI can accurately assess cortical gray matter and subcortical and periventricular white matter abnormalities 3 days after hypoxic-ischemic injury but appears to have limited sensitivity to detect injury to deep structures.
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Affiliation(s)
- Mhoyra Fraser
- Liggins Institute, University of Auckland, New Zealand. m.fraser@ auckland.ac.nz
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van den Heuij LG, Wassink G, Gunn AJ, Bennet L. Using Pregnant Sheep to Model Developmental Brain Damage. NEUROMETHODS 2016. [DOI: 10.1007/978-1-4939-3014-2_16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Affiliation(s)
- Elie Saliba
- Department of Neonatology; Centre Hospitalier Gatien de Clocheville; CHRU; Tours France
- INSERM Research Unit 930; University François Rabelais; Tours France
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Bell JE, Becher JC, Keeling JW, McIntosh N. The neuropathology of stillbirth - correlation with apolipoprotein genotype in a Scottish population based study. Early Hum Dev 2015; 91:139-48. [PMID: 25617864 DOI: 10.1016/j.earlhumdev.2014.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/11/2014] [Accepted: 12/28/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND The neuropathology of stillbirths has been widely studied but rarely on a population basis. Whether foetal apolipoprotein E (APOE) genotype exerts any influence has been little investigated, despite well known effects in adult brains. AIMS To establish the neuropathology of a population cohort of stillbirths and compare with the APOE genotype. STUDY DESIGN AND SUBJECTS The brains of 191 stillbirths (≥24weeks of gestation) were recruited from a Scottish population cohort and grouped by clinical history. APOE genotype was available for 97%. RESULTS AND CONCLUSIONS One or more neuropathological features, most appearing relatively recent, were found in 54% of 157 antepartum singletons, 44% of 9 abruption-associated stillbirths, 85% of 13 in multiple pregnancies but in only 19% of 12 intrapartum stillbirths. White matter injury (WMI) occurred in 36% of preterm and 21% mature stillbirths. Fresh petechial haemorrhages were common in all groups (29%) but germinal matrix haemorrhage (GMH) (7%) and periventricular leucomalacia (1%) were confined to preterm. GMH was significantly associated with WMI (p=0.003). Placental inflammation was common in intrapartum stillbirths (50%), compared with antepartum (15%), multiple pregnancy (23%) and abruption (0%). β-Amyloid precursor protein (βAPP) positive axons (36% stillbirths overall) correlated closely with WMI (p<0.0001), justifying future routine inclusion in foetal neuropathological investigation. This study highlights the paucity of brain damage in intrapartum stillbirths. While APOE2 was significantly overrepresented in stillbirths, there was no correlation between APOE genotype and neuropathological findings. We conclude that APOE does not influence neuropathological outcomes in stillbirths.
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Affiliation(s)
- Jeanne Elisabeth Bell
- Neuropathology, University of Edinburgh Division of Pathology, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.
| | - Julie-Clare Becher
- Child Life and Health, University of Edinburgh, 20 Sylvan Place, Edinburgh EH9 1UW, UK.
| | - Jean Winifred Keeling
- Paediatric Pathology, Royal Hospital for Sick Children, 9 Sciennes Rd, Edinburgh, Midlothian EH9 1LF, UK.
| | - Neil McIntosh
- Child Life and Health, University of Edinburgh, 20 Sylvan Place, Edinburgh EH9 1UW, UK.
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Drury PP, Davidson JO, Mathai S, van den Heuij LG, Ji H, Bennet L, Tan S, Silverman RB, Gunn AJ. nNOS inhibition during profound asphyxia reduces seizure burden and improves survival of striatal phenotypic neurons in preterm fetal sheep. Neuropharmacology 2014; 83:62-70. [PMID: 24726307 DOI: 10.1016/j.neuropharm.2014.03.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/17/2014] [Accepted: 03/31/2014] [Indexed: 12/01/2022]
Abstract
Basal ganglia injury after hypoxia-ischemia remains common in preterm infants, and is closely associated with later cerebral palsy. In the present study we tested the hypothesis that a highly selective neuronal nitric oxide synthase (nNOS) inhibitor, JI-10, would improve survival of striatal phenotypic neurons after profound asphyxia, and that the subsequent seizure burden and recovery of EEG are associated with neural outcome. 24 chronically instrumented preterm fetal sheep were randomized to either JI-10 (3 ml of 0.022 mg/ml, n = 8) or saline (n = 8) infusion 15 min before 25 min complete umbilical cord occlusion, or saline plus sham-occlusion (n = 8). Umbilical cord occlusion was associated with reduced numbers of calbindin-28k-, GAD-, NPY-, PV-, Calretinin- and nNOS-positive striatal neurons (p < 0.05 vs. sham occlusion) but not ChAT-positive neurons. JI-10 was associated with increased numbers of calbindin-28k-, GAD-, nNOS-, NPY-, PV-, Calretinin- and ChAT-positive striatal neurons (p < 0.05 vs. saline + occlusion). Seizure burden was strongly associated with loss of calbindin-positive cells (p < 0.05), greater seizure amplitude was associated with loss of GAD-positive cells (p < 0.05), and with more activated microglia in the white matter tracts (p < 0.05). There was no relationship between EEG power after 7 days recovery and total striatal cell loss, but better survival of NPY-positive neurons was associated with lower EEG power. In summary, these findings suggest that selective nNOS inhibition during asphyxia is associated with protection of phenotypic striatal projection neurons and has potential to help reduce basal ganglia injury in some premature babies.
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Affiliation(s)
- Paul P Drury
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Sam Mathai
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Haitao Ji
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208-3113, USA; Department of Chemistry, University of Utah, Salt Lake City, UT, USA
| | - Laura Bennet
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Sidhartha Tan
- Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL, USA
| | - Richard B Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208-3113, USA
| | - Alistair J Gunn
- Department of Physiology, University of Auckland, Auckland, New Zealand.
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Miller SL, Yawno T, Alers NO, Castillo-Melendez M, Supramaniam VG, VanZyl N, Sabaretnam T, Loose JM, Drummond GR, Walker DW, Jenkin G, Wallace EM. Antenatal antioxidant treatment with melatonin to decrease newborn neurodevelopmental deficits and brain injury caused by fetal growth restriction. J Pineal Res 2014; 56:283-94. [PMID: 24456220 DOI: 10.1111/jpi.12121] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 01/17/2014] [Indexed: 12/12/2022]
Abstract
Fetal intrauterine growth restriction (IUGR) is a serious pregnancy complication associated with increased rates of perinatal morbidity and mortality, and ultimately with long-term neurodevelopmental impairments. No intervention currently exists that can improve the structure and function of the IUGR brain before birth. Here, we investigated whether maternal antenatal melatonin administration reduced brain injury in ovine IUGR. IUGR was induced in pregnant sheep at 0.7 gestation and a subset of ewes received melatonin via intravenous infusion until term. IUGR, IUGR + melatonin (IUGR + MLT) and control lambs were born naturally, neonatal behavioral assessment was used to examine neurological function and at 24 hr after birth the brain was collected for the examination of neuropathology. Compared to control lambs, IUGR lambs took significantly longer to achieve normal neonatal lamb behaviors, such as standing and suckling. IUGR brains showed widespread cellular and axonal lipid peroxidation, and white matter hypomyelination and axonal damage. Maternal melatonin administration ameliorated oxidative stress, normalized myelination and rescued axonopathy within IUGR lamb brains, and IUGR + MLT lambs demonstrated significant functional improvements including a reduced time taken to attach to and suckle at the udder after birth. Based on these observations, we began a pilot clinical trial of oral melatonin administration to women with an IUGR fetus. Maternal melatonin was not associated with adverse maternal or fetal effects and it significantly reduced oxidative stress, as evidenced by reduced malondialdehyde levels, in the IUGR + MLT placenta compared to IUGR alone. Melatonin should be considered for antenatal neuroprotective therapy in human IUGR.
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Affiliation(s)
- Suzanne L Miller
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Vic., Australia; Department of Obstetrics & Gynaecology, Southern Clinical School, Monash University, Clayton, Vic., Australia
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Abstract
Children surviving premature birth have a high risk of cognitive and learning disabilities and attention deficit. In turn, adverse outcomes are associated with persistent reductions in cerebral growth on magnetic resonance imaging (MRI). It is striking that modern care has been associated with a dramatic reduction in the risk of cystic white matter damage, but modest improvements in terms of neurodevelopmental impairment. This review will explore the hypothesis that the disability is primarily associated with impaired neural connectivity rather than cell death alone. Very preterm infants exhibit reduced thalamocortical connectivity and cortical neuroplasticity compared with term-born controls. In preterm fetal sheep, moderate cerebral ischemia with no neuronal loss, but significant diffuse failure of maturation of cortical pyramidal neurons, was associated with impaired dendritic growth and synapse formation, consistent with altered connectivity. These changes were associated with delayed decline in cortical fractional anisotropy (FA) on MRI. Supporting these preclinical findings, preterm human survivors showed similar enduring impairment of microstructural development of the cerebral cortex defined by FA, consistent with delayed formation of neuronal processes. These findings offer the promise that better understanding of impairment of neural connectivity may allow us to promote normal development and growth of the cortex after preterm birth.
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Huang W, Besar K, LeCover R, Dulloor P, Sinha J, Martínez Hardigree JF, Pick C, Swavola J, Everett AD, Frechette J, Bevan M, Katz HE. Label-free brain injury biomarker detection based on highly sensitive large area organic thin film transistor with hybrid coupling layer. Chem Sci 2014. [DOI: 10.1039/c3sc52638k] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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13
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Alix JJP, Zammit C, Riddle A, Meshul CK, Back SA, Valentino M, Fern R. Central axons preparing to myelinate are highly sensitive [corrected] to ischemic injury. Ann Neurol 2013; 72:936-51. [PMID: 23280842 DOI: 10.1002/ana.23690] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 05/22/2012] [Accepted: 06/15/2012] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Developing central white matter is subject to ischemic-type injury during the period that precedes myelination. At this stage in maturation, central axons initiate a program of radial expansion and ion channel redistribution. Here we test the hypothesis that during radial expansion axons display heightened ischemic sensitivity, when clusters of Ca(2+) channels decorate future node of Ranvier sites. METHODS Functionality and morphology of central axons and glia were examined during and after a period of modeled ischemia. Pathological changes in axons undergoing radial expansion were probed using electrophysiological, quantitative ultrastructural, and morphometric analysis in neonatal rodent optic nerve and periventricular white matter axons studied under modeled ischemia in vitro or after hypoxia-ischemia in vivo. RESULTS Acute ischemic injury of central axons undergoing initial radial expansion was mediated by Ca(2+) influx through Ca(2+) channels expressed in axolemma clusters. This form of injury operated only in this axon population, which was more sensitive to injury than neighboring myelinated axons, smaller axons yet to initiate radial expansion, astrocytes, or oligodendroglia. A pharmacological strategy designed to protect both small and large diameter premyelinated axons proved 100% protective against acute ischemia studied under modeled ischemia in vitro or after hypoxia-ischemia in vivo. INTERPRETATION Recent clinical data highlight the importance of axon pathology in developing white matter injury. The elevated susceptibility of early maturing axons to ischemic injury described here may significantly contribute to selective white matter pathology and places these axons alongside preoligodendrocytes as a potential primary target of both injury and therapeutics.
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Affiliation(s)
- James J P Alix
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, United Kingdom
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Retrospective Case-Control Study of Apolipoprotein J/Clusterin Protein Expression in Early Liveborn Neonatal Deaths with and without Pontosubicular Necrosis. PATHOLOGY RESEARCH INTERNATIONAL 2012; 2012:479359. [PMID: 22848862 PMCID: PMC3403500 DOI: 10.1155/2012/479359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 03/23/2012] [Indexed: 11/18/2022]
Abstract
Aims. Our objective was to examine Apo J protein expression in a total of 27 early liveborn neonatal deaths (less than 7 days of age) selected from the Scottish Perinatal Study (gestation of 25–42 weeks) comparing a group with histological pontosubicular necrosis (PSN) (n = 12) to a control group lacking PSN (n = 15). Methods. Using immunohistochemistry we evaluated postmortem pons and hippocampus from patients with PSN versus controls. Results. In the group with PSN, 11/12 (92%) cases showed positive Apo J neurones in the hippocampus/pons compared with 6/15 (40%) cases without PSN (P = 0.014, odds ratio 27.5, 95% confidence interval 2.881–262.48, using exact logistic regression)—independent of gestation, presence or absence of clinical asphyxia, duration of labour, or postnatal age. Clinical asphyxia was present in 10/15 (67%) without PSN compared with 11/12 (92%) with PSN. Neuronal Apo J positivity was present in 15/21 (71%) of clinically asphyxiated cases compared with 2/6 (33%) of the cases with no evidence of clinical asphyxia (P = 0.154, odds ratio 5, 95% confidence interval 0.71 to 34.94). Conclusions. Apo J neuronal protein expression is significantly increased in cases with PSN compared to cases without PSN—independent of gestation, presence of clinical asphyxia, duration of labour, or postnatal age.
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Volpe JJ. Systemic inflammation, oligodendroglial maturation, and the encephalopathy of prematurity. Ann Neurol 2012; 70:525-9. [PMID: 22028217 DOI: 10.1002/ana.22533] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Maxwell WL. Traumatic brain injury in the neonate, child and adolescent human: An overview of pathology. Int J Dev Neurosci 2011; 30:167-83. [DOI: 10.1016/j.ijdevneu.2011.12.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 10/27/2011] [Accepted: 12/16/2011] [Indexed: 01/14/2023] Open
Affiliation(s)
- William L. Maxwell
- Anatomy, Thomson BuildingSchool of Medicine Veterinary Medicine and Life SciencesUniversity of GlasgowGlasgowG12 8QQScotlandUnited Kingdom
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George S, Bennet L, Weaver-Mikaere L, Fraser M, Bouwmans J, Mathai S, Skinner S, Gunn A. White Matter Protection with Insulin-Like Growth Factor 1 and Hypothermia Is Not Additive after Severe Reversible Cerebral Ischemia in Term Fetal Sheep. Dev Neurosci 2011; 33:280-7. [DOI: 10.1159/000329923] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 06/06/2011] [Indexed: 12/13/2022] Open
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Volpe JJ, Kinney HC, Jensen FE, Rosenberg PA. Reprint of "The developing oligodendrocyte: key cellular target in brain injury in the premature infant". Int J Dev Neurosci 2011; 29:565-82. [PMID: 21802506 DOI: 10.1016/j.ijdevneu.2011.07.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Brain injury in the premature infant, a problem of enormous importance, is associated with a high risk of neurodevelopmental disability. The major type of injury involves cerebral white matter and the principal cellular target is the developing oligodendrocyte. The specific phase of the oligodendroglial lineage affected has been defined from study of both human brain and experimental models. This premyelinating cell (pre-OL) is vulnerable because of a series of maturation-dependent events. The pathogenesis of pre-OL injury relates to operation of two upstream mechanisms, hypoxia-ischemia and systemic infection/inflammation, both of which are common occurrences in premature infants. The focus of this review and of our research over the past 15-20 years has been the cellular and molecular bases for the maturation-dependent vulnerability of the pre-OL to the action of the two upstream mechanisms. Three downstream mechanisms have been identified, i.e., microglial activation, excitotoxicity and free radical attack. The work in both experimental models and human brain has identified a remarkable confluence of maturation-dependent factors that render the pre-OL so exquisitely vulnerable to these downstream mechanisms. Most importantly, elucidation of these factors has led to delineation of a series of potential therapeutic interventions, which in experimental models show marked protective properties. The critical next step, i.e., clinical trials in the living infant, is now on the horizon.
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Affiliation(s)
- Joseph J Volpe
- Department of Neurology, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Ball G, Boardman JP, Rueckert D, Aljabar P, Arichi T, Merchant N, Gousias IS, Edwards AD, Counsell SJ. The effect of preterm birth on thalamic and cortical development. Cereb Cortex 2011; 22:1016-24. [PMID: 21772018 PMCID: PMC3328341 DOI: 10.1093/cercor/bhr176] [Citation(s) in RCA: 230] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Preterm birth is a leading cause of cognitive impairment in childhood and is associated with cerebral gray and white matter abnormalities. Using multimodal image analysis, we tested the hypothesis that altered thalamic development is an important component of preterm brain injury and is associated with other macro- and microstructural alterations. T1- and T2-weighted magnetic resonance images and 15-direction diffusion tensor images were acquired from 71 preterm infants at term-equivalent age. Deformation-based morphometry, Tract-Based Spatial Statistics, and tissue segmentation were combined for a nonsubjective whole-brain survey of the effect of prematurity on regional tissue volume and microstructure. Increasing prematurity was related to volume reduction in the thalamus, hippocampus, orbitofrontal lobe, posterior cingulate cortex, and centrum semiovale. After controlling for prematurity, reduced thalamic volume predicted: lower cortical volume; decreased volume in frontal and temporal lobes, including hippocampus, and to a lesser extent, parietal and occipital lobes; and reduced fractional anisotropy in the corticospinal tracts and corpus callosum. In the thalamus, reduced volume was associated with increased diffusivity. This demonstrates a significant effect of prematurity on thalamic development that is related to abnormalities in allied brain structures. This suggests that preterm delivery disrupts specific aspects of cerebral development, such as the thalamocortical system.
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Affiliation(s)
- Gareth Ball
- Centre for Developing Brain, Imperial College London and MRC Clinical Sciences Centre, Hammersmith Hospital, London W12 0NN, UK
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Volpe JJ, Kinney HC, Jensen FE, Rosenberg PA. The developing oligodendrocyte: key cellular target in brain injury in the premature infant. Int J Dev Neurosci 2011; 29:423-40. [PMID: 21382469 DOI: 10.1016/j.ijdevneu.2011.02.012] [Citation(s) in RCA: 258] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/10/2011] [Accepted: 02/27/2011] [Indexed: 01/16/2023] Open
Abstract
Brain injury in the premature infant, a problem of enormous importance, is associated with a high risk of neurodevelopmental disability. The major type of injury involves cerebral white matter and the principal cellular target is the developing oligodendrocyte. The specific phase of the oligodendroglial lineage affected has been defined from study of both human brain and experimental models. This premyelinating cell (pre-OL) is vulnerable because of a series of maturation-dependent events. The pathogenesis of pre-OL injury relates to operation of two upstream mechanisms, hypoxia-ischemia and systemic infection/inflammation, both of which are common occurrences in premature infants. The focus of this review and of our research over the past 15-20 years has been the cellular and molecular bases for the maturation-dependent vulnerability of the pre-OL to the action of the two upstream mechanisms. Three downstream mechanisms have been identified, i.e., microglial activation, excitotoxicity and free radical attack. The work in both experimental models and human brain has identified a remarkable confluence of maturation-dependent factors that render the pre-OL so exquisitely vulnerable to these downstream mechanisms. Most importantly, elucidation of these factors has led to delineation of a series of potential therapeutic interventions, which in experimental models show marked protective properties. The critical next step, i.e., clinical trials in the living infant, is now on the horizon.
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Affiliation(s)
- Joseph J Volpe
- Department of Neurology, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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21
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Matturri L, Lavezzi AM. Unexplained stillbirth versus SIDS: common congenital diseases of the autonomic nervous system--pathology and nosology. Early Hum Dev 2011; 87:209-15. [PMID: 21262556 DOI: 10.1016/j.earlhumdev.2010.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/10/2010] [Accepted: 12/20/2010] [Indexed: 01/02/2023]
Abstract
OBJECTIVE To contribute to a more balanced assessment of the morphological substrates underlying unexplained perinatal death and SIDS. METHODS In-depth histological, immunohistochemical and genetic examinations were performed on the autonomic nervous and cardiac conduction systems in 95 unexpected perinatal deaths, 140 SIDS and 78 controls (44 infants and 34 perinatal death victims). RESULTS The study revealed the localization and the nature of a variety of specific congenital abnormalities of the autonomic nervous system, central and peripheral, and of the cardiac conduction system that represent the morphological substrates of the pathophysiological mechanism of sudden fetal death and SIDS. CONCLUSIONS The observation of similar anomalies of the autonomic nervous and the cardiac conduction systems in both unexplained perinatal deaths and SIDS indicates their common congenital nature. Therefore, the definitions of these deaths, currently nosographically distinct, should be unified.
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Affiliation(s)
- Luigi Matturri
- Lino Rossi Research Center for the Study and Prevention of Sudden Perinatal Death and SIDS, Department of Surgical, Reconstructive and Diagnostic Sciences, University of Milan, Milan 20122, Italy.
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Dean J, Farrag D, Zahkouk S, El Zawahry E, Hagberg H, Kjellmer I, Mallard C. Cerebellar white matter injury following systemic endotoxemia in preterm fetal sheep. Neuroscience 2009; 160:606-15. [DOI: 10.1016/j.neuroscience.2009.02.071] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/24/2009] [Accepted: 02/26/2009] [Indexed: 10/21/2022]
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23
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Volpe JJ. Brain injury in premature infants: a complex amalgam of destructive and developmental disturbances. Lancet Neurol 2009; 8:110-24. [PMID: 19081519 DOI: 10.1016/s1474-4422(08)70294-1] [Citation(s) in RCA: 1679] [Impact Index Per Article: 111.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Brain injury in premature infants is of enormous public health importance because of the large number of such infants who survive with serious neurodevelopmental disability, including major cognitive deficits and motor disability. This type of brain injury is generally thought to consist primarily of periventricular leukomalacia (PVL), a distinctive form of cerebral white matter injury. Important new work shows that PVL is frequently accompanied by neuronal/axonal disease, affecting the cerebral white matter, thalamus, basal ganglia, cerebral cortex, brain stem, and cerebellum. This constellation of PVL and neuronal/axonal disease is sufficiently distinctive to be termed "encephalopathy of prematurity". The thesis of this Review is that the encephalopathy of prematurity is a complex amalgam of primary destructive disease and secondary maturational and trophic disturbances. This Review integrates the fascinating confluence of new insights into both brain injury and brain development during the human premature period.
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Affiliation(s)
- Joseph J Volpe
- Department of Neurology, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Abstract
There is strong evidence that prolonged, moderate cerebral hypothermia initiated within a few hours after severe hypoxia-ischemia and continued until resolution of the acute phase of delayed cell death can reduce neuronal loss and improve behavioral recovery in term infants and adults after cardiac arrest. This review examines the evidence that mild to moderate hypothermia is protective after hypoxia-ischemia in models of preterm brain injury and evaluates the potential risks. Induced hypothermia likely has potential to significantly reduce disability. Cautious, systematic trials are essential before hypothermia can be used in these vulnerable infants.
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Affiliation(s)
- Alistair Jan Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Loukovaara M, Teramo K, Alfthan H, Hämäläinen E, Stefanovic V, Andersson S. Amniotic fluid S100B protein and erythropoietin in pregnancies at risk for fetal hypoxia. Eur J Obstet Gynecol Reprod Biol 2008; 142:115-8. [PMID: 19042077 DOI: 10.1016/j.ejogrb.2008.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 08/29/2008] [Accepted: 10/05/2008] [Indexed: 11/19/2022]
Abstract
OBJECTIVE S100B protein is a biochemical marker for brain injury, and high serum S100B levels have been observed in newborns with birth asphyxia. We hypothesized that the concentration of amniotic fluid erythropoietin, which increases in chronic fetal hypoxia, correlates with amniotic fluid S100B concentration. STUDY DESIGN Amniotic fluid samples in 35 pregnancies at high risk for chronic fetal hypoxia were obtained at cesarean section or by amniocentesis done within a median of 2 days before delivery. S100B and erythropoietin concentrations were measured by chemiluminescent immunoassays. RESULTS A positive correlation existed between the concentrations of S100B and erythropoietin in the amniotic fluid (r=0.57, p<0.0001). Amniotic fluid S100B concentration was higher (70 ng/l; 33-469, n=17) (median; range) in pregnancies with elevated amniotic fluid erythropoietin (>or= 50 IU/l) than in pregnancies with normal erythropoietin (34 ng/l; 20-340, n=18) (p<0.0001, Mann-Whitney U-test). S100B predicted an elevated amniotic fluid erythropoietin concentration in the study population with the sensitivity of 94% and specificity of 83%. CONCLUSION A strong positive correlation exists between amniotic fluid S100B and erythropoietin concentrations in pregnancies at high risk for chronic fetal hypoxia. This suggests that chronic fetal hypoxia increases the intrauterine release of S100B.
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Affiliation(s)
- Mikko Loukovaara
- Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Haartmaninkatu 2, 00290 Helsinki, Finland.
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Matturri L, Mauri M, Ferrero ME, Lavezzi AM. Unexpected perinatal loss versus Sids-a common neuropathologic entity. Open Neurol J 2008; 2:45-50. [PMID: 19018308 PMCID: PMC2577929 DOI: 10.2174/1874205x00802010045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 11/22/2022] Open
Abstract
Objective: To evaluate the involvement of alterations of the central autonomic nervous system, particularly of the brainstem and cerebellum, in a wide set of victims of sudden and unexplained perinatal and infant death. Material and Methods: The study population consisted of 63 stillbirths, 28 neonatal deaths and 140 suspected SIDS. The victims were subjected to in-depth anatomopathological examination following appropriate guidelines. The protocol included, in particular, the histological evaluation on serial sections of the cardiorespiratory autonomic nervous system. Results: A diagnosis of “unexplained death” was established for 217 of the 231 victims (59 stillbirths, 28 newborns and 130 SIDS). In a very high percentage of these deaths (84%) we observed one or more anomalies of the nuclei and/or structures of the brainstem and cerebellum related to vital functions. Conclusion: Unexpected perinatal loss should not be regarded as a separate entity from SIDS, given the common neuropathological substrates.
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Affiliation(s)
- Luigi Matturri
- Lino Rossi" Research Center for the study and prevention of unexpected perinatal death and SIDS, University of Milan, Italy.
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Pierson CR, Folkerth RD, Billiards SS, Trachtenberg FL, Drinkwater ME, Volpe JJ, Kinney HC. Gray matter injury associated with periventricular leukomalacia in the premature infant. Acta Neuropathol 2007; 114:619-31. [PMID: 17912538 PMCID: PMC2080348 DOI: 10.1007/s00401-007-0295-5] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 09/10/2007] [Accepted: 09/10/2007] [Indexed: 01/26/2023]
Abstract
Neuroimaging studies indicate reduced volumes of certain gray matter regions in survivors of prematurity with periventricular leukomalacia (PVL). We hypothesized that subacute and/or chronic gray matter lesions are increased in incidence and severity in PVL cases compared to non-PVL cases at autopsy. Forty-one cases of premature infants were divided based on cerebral white matter histology: PVL (n = 17) with cerebral white matter gliosis and focal periventricular necrosis; diffuse white matter gliosis (DWMG) (n = 17) without necrosis; and “ Negative” group (n = 7) with no abnormalities. Neuronal loss was found almost exclusively in PVL, with significantly increased incidence and severity in the thalamus (38%), globus pallidus (33%), and cerebellar dentate nucleus (29%) compared to DWMG cases. The incidence of gliosis was significantly increased in PVL compared to DWMG cases in the deep gray nuclei (thalamus/basal ganglia; 50–60% of PVL cases), and basis pontis (100% of PVL cases). Thalamic and basal ganglionic lesions occur almost exclusively in infants with PVL. Gray matter lesions occur in a third or more of PVL cases suggesting that white matter injury generally does not occur in isolation, and that the term “perinatal panencephalopathy” may better describe the scope of the neuropathology.
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McCarran WJ, Goldberg MP. White matter axon vulnerability to AMPA/kainate receptor-mediated ischemic injury is developmentally regulated. J Neurosci 2007; 27:4220-9. [PMID: 17429000 PMCID: PMC6672529 DOI: 10.1523/jneurosci.5542-06.2007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Periventricular white matter injury (PWMI) is the leading cause of neurodevelopmental morbidity in survivors of premature birth. Cerebral ischemia is considered a major etiologic factor in the generation of PWMI. In adult white matter (WM), ischemic axonal damage is mediated by AMPA/kainate receptors. Mechanisms of ischemic axonal injury during development are not well defined. We used a murine brain slice model to characterize mechanisms of ischemic axonal injury in developing WM. Acute coronal brain slices were prepared from thy1-yellow fluorescent protein (YFP) mice at postnatal day 3 (P3), P7, P10, and P21. Ischemia was simulated by oxygen-glucose deprivation (OGD). YFP-positive axon morphology in the corpus callosum was preserved for at least 15 h under normoxic conditions. OGD resulted in delayed degeneration of YFP-positive axons, characterized by axonal beading, fragmentation, and loss of YFP. AMPA and cyclothiazide damaged WM axons at P7, P10, and P21 but not at P3. The AMPA/kainate receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) decreased OGD-induced axonal degeneration and oligodendrocyte loss at P10 and P21. At P3 and P7, NBQX protected oligodendrocytes but did not prevent axonal degeneration after OGD. The NMDA receptor antagonist MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] provided no protection at any age. These results indicate that developing WM axons are susceptible to ischemic injury. However, mechanisms of axonal degeneration are developmentally regulated. At P3 and P7, corresponding developmentally to the window of peak vulnerability to PWMI in humans, ischemic axonal injury is not mediated by AMPA/kainate receptors. Strategies to protect WM during this period may be substantially different from those used at later developmental stages.
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Affiliation(s)
| | - Mark P. Goldberg
- Hope Center for Neurological Disorders and
- Neurology, Washington University School of Medicine, St. Louis, Missouri 63110
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Barrett RD, Bennet L, Davidson J, Dean JM, George S, Emerald BS, Gunn AJ. Destruction and reconstruction: Hypoxia and the developing brain. ACTA ACUST UNITED AC 2007; 81:163-76. [DOI: 10.1002/bdrc.20095] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Burke CJ, Tannenberg AET. Intrapartum stillbirths in hospital unrelated to uteroplacental vascular insufficiency. Pediatr Dev Pathol 2007; 10:35-40. [PMID: 17378621 DOI: 10.2350/06-02-0042.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 07/18/2006] [Indexed: 11/20/2022]
Abstract
The aim of this study was to investigate the causes of intrapartum asphyxia and its relationship to placental abnormalities. Twenty intrapartum fetal death autopsies carried out over a 10-year period in one hospital pathology department associated with a large obstetric unit were reviewed. All the intrapartum fetal deaths occurred in the hospital, while the mothers were being monitored during and after labor. On morphologic grounds, all the fetal deaths were thought to be caused by intrapartum asphyxia. Seven of the intrapartum fetal deaths were associated with intrauterine infection causing funisitis, and in 6 of these cases, chorioamnionitis was present as well. Two cases were caused by placental abruption, and 1 case was caused by cord compression. In 8 of the 10 remaining cases in which the placenta was examined, a minor placental abnormality was detected in only 1 case. Five of the 10 cases had a mild astrocytosis in the intracerebral periventricular white matter, suggestive of intrauterine ischemia at least 12 hours before death. Five of the 10 cases were thought by the delivering obstetrician to have umbilical cord abnormalities. The main conclusions from this study are that, except in cases of intrauterine infection, placental vascular abnormalities are unlikely to be associated with intrapartum asphyxia leading to fetal death during labor. The number of cases with umbilical cord abnormalities raises the possibility that cord accidents may be a significant cause of intrapartum stillbirth.
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George S, Scotter J, Dean JM, Bennet L, Waldvogel HJ, Guan J, Faull RLM, Gunn AJ. Induced cerebral hypothermia reduces post-hypoxic loss of phenotypic striatal neurons in preterm fetal sheep. Exp Neurol 2007; 203:137-47. [PMID: 16962098 DOI: 10.1016/j.expneurol.2006.07.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 07/17/2006] [Accepted: 07/28/2006] [Indexed: 12/20/2022]
Abstract
Perinatal hypoxic-ischemic injury of the basal ganglia is a significant cause of disability in premature infants. Prolonged, moderate cerebral hypothermia has been shown to be neuroprotective after experimental hypoxia-ischemia; however, it has not been tested in the preterm brain. We therefore examined the effects of severe hypoxia and the potential neuroprotective effects of delayed hypothermia on phenotypic striatal neurons. Preterm (0.7 gestation) fetal sheep received complete umbilical cord occlusion for 25 min followed by cerebral hypothermia (fetal extradural temperature reduced from 39.4+/-0.3 degrees C to 29.5+/-2.6 degrees C) from 90 min to 70 h after the end of occlusion. Hypothermia was associated with a significant overall reduction in striatal neuronal loss compared with normothermia-occlusion fetuses (mean+/-SEM, 5.5+/-1.2% vs. 38.1+/-6.5%, P<0.01). Immunohistochemical studies showed that occlusion resulted in a significant loss of calbindin-28 kd, glutamic acid decarboxylase isoform 67 and neuronal nitric oxide synthase-immunopositive neurons (n=7, P<0.05), but not choline acetyltransferase-positive neurons, compared with sham controls (n=7). Hypothermia (n=7) significantly reduced the loss of calbindin-28 kd and neuronal nitric oxide synthase, but not glutamic acid decarboxylase-immunopositive neurons. In conclusion, delayed, prolonged moderate head cooling was associated with selective protection of particular phenotypic striatal projection neurons after severe hypoxia in the preterm fetus. These findings suggest that head cooling may help reduce basal ganglia injury in some premature babies.
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Affiliation(s)
- S George
- Department of Physiology, Faculty of Medicine and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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Bennet L, Roelfsema V, George S, Dean JM, Emerald BS, Gunn AJ. The effect of cerebral hypothermia on white and grey matter injury induced by severe hypoxia in preterm fetal sheep. J Physiol 2006; 578:491-506. [PMID: 17095565 PMCID: PMC2075155 DOI: 10.1113/jphysiol.2006.119602] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Prolonged, moderate cerebral hypothermia is consistently neuroprotective after experimental hypoxia-ischaemia; however, it has not been tested in the preterm brain. Preterm (0.7 gestation) fetal sheep received complete umbilical cord occlusion for 25 min followed by cerebral hypothermia (fetal extradural temperature reduced from 39.4 +/- 0.3 to 29.5 +/- 2.6 degrees C) from 90 min to 70 h after the end of occlusion or sham cooling. Occlusion led to severe acidosis and profound hypotension, which recovered rapidly after release of occlusion. After 3 days recovery the EEG spectral frequency, but not total intensity, was increased in the hypothermia-occlusion group compared with normothermia-occlusion. Hypothermia was associated with a significant overall reduction in loss of immature oligodendrocytes in the periventricular white matter (P < 0.001), and neuronal loss in the hippocampus and basal ganglia (P < 0.001), with suppression of activated caspase-3 and microglia (isolectin-B4 positive). Proliferation was significantly reduced in periventricular white matter after occlusion (P < 0.05), but not improved after hypothermia. In conclusion, delayed, prolonged head cooling after a profound hypoxic insult in the preterm fetus was associated with a significant reduction in loss of neurons and immature oligodendroglia, with evidence of EEG and haemodynamic improvement after 3 days recovery, but also with a persisting reduction in proliferation of cells in the periventricular region. Further studies are required to evaluate the long-term impact of cooling on brain growth and maturation.
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Affiliation(s)
- L Bennet
- Department of Physiology and Paediatrics, University of Auckland, Auckland, New Zealand
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