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Ventura GC, Dyshliuk N, Dmytriyeva O, Nordsten MJB, Haugaard MM, Christiansen LI, Thymann T, Sangild PT, Pankratova S. Enteral plasma supports brain repair in newborn pigs after birth asphyxia. Brain Behav Immun 2024; 119:693-708. [PMID: 38677626 DOI: 10.1016/j.bbi.2024.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/03/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024] Open
Abstract
Newborns exposed to birth asphyxia transiently experience deficient blood flow and a lack of oxygen, potentially inducing hypoxic-ischaemic encephalopathy and subsequent neurological damage. Immunomodulatory components in plasma may dampen these responses. Using caesarean-delivered pigs as a model, we hypothesized that dietary plasma supplementation improves brain outcomes in pigs exposed to birth asphyxia. Mild birth asphyxia was induced by temporary occlusion of the umbilical cord prior to caesarean delivery. Motor development was assessed in asphyxiated (ASP) and control (CON) piglets using neonatal arousal, physical activity and gait test parameters before euthanasia on Day 4. The ASP pigs exhibited increased plasma lactate at birth, deficient motor skills and increased glial fibrillary acidic protein levels in CSF and astrogliosis in the putamen. The expression of genes related to oxidative stress, inflammation and synaptic functions was transiently altered in the motor cortex and caudate nucleus. The number of apoptotic cells among CTIP2-positive neurons in the motor cortex and striatal medium spiny neurons was increased, and maturation of preoligodendrocytes in the internal capsule was delayed. Plasma supplementation improved gait performance in the beam test, attenuated neuronal apoptosis and affected gene expression related to neuroinflammation, neurotransmission and antioxidants (motor cortex, caudate). We present a new clinically relevant animal model of moderate birth asphyxia inducing structural and functional brain damage. The components in plasma that support brain repair remain to be identified but may represent a therapeutic potential for infants and animals after birth asphyxia.
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Affiliation(s)
- Gemma Chavarria Ventura
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nadiya Dyshliuk
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; National University of Life and Environmental Sciences of Ukraine, Kyiv, Ukraine
| | - Oksana Dmytriyeva
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mads Jacob Bagi Nordsten
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria Mathilde Haugaard
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Line Iadsatian Christiansen
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Thymann
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Per Torp Sangild
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen, Denmark; Department of Pediatrics, Odense University Hospital, Odense, Denmark
| | - Stanislava Pankratova
- Section of Comparative Pediatrics and Nutrition, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Benavides-Lara J, Manwar R, McGuire LS, Islam MT, Shoo A, Charbel FT, Menchaca MG, Siegel AP, Pillers DAM, Gelovani JG, Avanaki K. Transfontanelle photoacoustic imaging of intraventricular brain hemorrhages in live sheep. PHOTOACOUSTICS 2023; 33:100549. [PMID: 37664559 PMCID: PMC10474607 DOI: 10.1016/j.pacs.2023.100549] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/05/2023]
Abstract
Intraventricular (IVH) and periventricular (PVH) hemorrhages in preterm neonates are common because the periventricular blood vessels are still developing up to 36 weeks and are fragile. Currently, transfontanelle ultrasound (US) imaging is utilized for screening for IVH and PVH, largely through the anterior fontanelle. However for mild hemorrhages, inconclusive diagnoses are common, leading to failure to detect IVH/PVH or, when other clinical symptoms are present, use of second stage neuroimaging modalities requiring transport of vulnerable patients. Yet even mild IVH/PVH increases the risk of moderate-severe neurodevelopmental impairment. Here, we demonstrate the capability of transfontanelle photoacoustic imaging (TFPAI) to detect IVH and PVH in-vivo in a large animal model. TFPAI was able to detect IVH/PVH as small as 0.3 mL in volume in the brain (p < 0.05). By contrast, US was able to detect hemorrhages as small as 0.5 mL. These preliminary results suggest TFPAI could be translated into a portable bedside imaging probe for improved diagnosis of clinically relevant brain hemorrhages in neonates.
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Affiliation(s)
- Juliana Benavides-Lara
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Rayyan Manwar
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Laura S McGuire
- Department of Neurological Surgery, University of Illinois at Chicago - College of Medicine, Chicago, IL, United States
| | - Md Tarikul Islam
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Anthony Shoo
- Section of Neonatology, Department of Pediatrics, UIHealth Children's Hospital of the University of Illinois at Chicago, Chicago, IL, United States
| | - Fady T Charbel
- Department of Neurological Surgery, University of Illinois at Chicago - College of Medicine, Chicago, IL, United States
| | - Martha G Menchaca
- Section of Neonatology, Department of Pediatrics, UIHealth Children's Hospital of the University of Illinois at Chicago, Chicago, IL, United States
| | - Amanda P Siegel
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - De-Ann M Pillers
- Section of Neonatology, Department of Pediatrics, UIHealth Children's Hospital of the University of Illinois at Chicago, Chicago, IL, United States
| | - Juri G Gelovani
- Provost Office, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE
- Department of Biomedical Engineering, College of Engineering and School of Medicine, Wayne State University, Detroit, MI 48201, United States
- Dept. Radiology, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Kamran Avanaki
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
- Section of Neonatology, Department of Pediatrics, UIHealth Children's Hospital of the University of Illinois at Chicago, Chicago, IL, United States
- Department of Dermatology, University of Illinois at Chicago, Chicago, IL, United States
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3
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Manwar R, Kratkiewicz K, Mahmoodkalayeh S, Hariri A, Papadelis C, Hansen A, Pillers DAM, Gelovani J, Avanaki K. Development and characterization of transfontanelle photoacoustic imaging system for detection of intracranial hemorrhages and measurement of brain oxygenation: Ex-vivo. PHOTOACOUSTICS 2023; 32:100538. [PMID: 37575972 PMCID: PMC10413353 DOI: 10.1016/j.pacs.2023.100538] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 06/28/2023] [Accepted: 07/19/2023] [Indexed: 08/15/2023]
Abstract
We have developed and optimized an imaging system to study and improve the detection of brain hemorrhage and to quantify oxygenation. Since this system is intended to be used for brain imaging in neonates through the skull opening, i.e., fontanelle, we called it, Transfontanelle Photoacoustic Imaging (TFPAI) system. The system is optimized in terms of optical and acoustic designs, thermal safety, and mechanical stability. The lower limit of quantification of TFPAI to detect the location of hemorrhage and its size is evaluated using in-vitro and ex-vivo experiments. The capability of TFPAI in measuring the tissue oxygenation and detection of vasogenic edema due to brain blood barrier disruption are demonstrated. The results obtained from our experimental evaluations strongly suggest the potential utility of TFPAI, as a portable imaging modality in the neonatal intensive care unit. Confirmation of these findings in-vivo could facilitate the translation of this promising technology to the clinic.
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Affiliation(s)
- Rayyan Manwar
- University of Illinois at Chicago, Department of Biomedical Engineering, Chicago, IL, United States
| | - Karl Kratkiewicz
- Barbara Ann Karmanos Cancer Institute, Detroit, MI, United States
| | | | - Ali Hariri
- Department of Nanoengineering, University of California, San Diego, CA, United States
| | - Christos Papadelis
- Jane and John Justin Neurosciences Center, Cook Children’s Health Care System, Fort Worth, TX, United States
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, United States
| | - Anne Hansen
- Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
| | - De-Ann M. Pillers
- Department of Pediatrics, UI Health Children’s Hospital of the University of Illinois at Chicago, Chicago, IL, United States
| | - Juri Gelovani
- College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE
- Department of Biomedical Engineering, College of Engineering and School of Medicine, Wayne State University, Detroit, MI 48201, United States
- Dept. Radiology, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Kamran Avanaki
- University of Illinois at Chicago, Department of Biomedical Engineering, Chicago, IL, United States
- Department of Pediatrics, UI Health Children’s Hospital of the University of Illinois at Chicago, Chicago, IL, United States
- Department of Dermatology, University of Illinois at Chicago, Chicago, IL, United States
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Montaldo P, Thayyil S. Hippocampus and hypothermia: A missing link. Dev Med Child Neurol 2023; 65:303-304. [PMID: 36161444 PMCID: PMC10087901 DOI: 10.1111/dmcn.15427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 09/05/2022] [Indexed: 11/26/2022]
Affiliation(s)
- Paolo Montaldo
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Sudhin Thayyil
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
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Transfontanelle photoacoustic imaging for in-vivo cerebral oxygenation measurement. Sci Rep 2022; 12:15394. [PMID: 36100615 PMCID: PMC9470703 DOI: 10.1038/s41598-022-19350-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 08/29/2022] [Indexed: 11/25/2022] Open
Abstract
The capability of photoacoustic (PA) imaging to measure oxygen saturation through a fontanelle has been demonstrated in large animals in-vivo. We called this method, transfontanelle photoacoustic imaging (TFPAI). A surgically induced 2.5 cm diameter cranial window was created in an adult sheep skull to model the human anterior fontanelle. The performance of the TFPAI has been evaluated by comparing the PA-based predicted results against the gold standard of blood gas analyzer measurements.
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Davidson JO, van den Heuij LG, Dhillon SK, Miller SL, Lim R, Jenkin G, Gunn AJ, Bennet L. Lack of Neuroprotection with a Single Intravenous Infusion of Human Amnion Epithelial Cells after Severe Hypoxia–Ischemia in Near-Term Fetal Sheep. Int J Mol Sci 2022; 23:ijms23158393. [PMID: 35955531 PMCID: PMC9369428 DOI: 10.3390/ijms23158393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 12/02/2022] Open
Abstract
Background: Hypoxic–ischemic encephalopathy (HIE) around the time of birth results from loss of oxygen (hypoxia) and blood supply (ischemia). Exogenous infusion of multi-potential cells, including human amnion epithelial cells (hAECs), can reduce hypoxic–ischemic (HI) brain injury. However, there are few data on treatment of severe HI in large animal paradigms at term. The aim of the current study was to determine whether infusion of hAECs early after injury may reduce brain damage after ischemia in near-term fetal sheep. Methods: Chronically instrumented fetal sheep (0.85 gestation) received 30 min of global cerebral ischemia followed by intravenous infusion of hAECs from 2 h after the end of ischemia (ischemia-hAEC, n = 6) or saline (ischemia-vehicle, n = 7). Sham control animals received sham ischemia with vehicle infusion (sham control, n = 8). Results: Ischemia was associated with significant suppression of EEG power and spectral edge frequency until the end of the experiment and a secondary rise in cortical impedance from 24 to 72 h, which were not attenuated by hAEC administration. Ischemia was associated with loss of neurons in the cortex, thalamus, striatum and hippocampus, loss of white matter oligodendrocytes and increased microglial numbers in the white matter, which were not affected by hAEC infusion. Conclusions: A single intravenous administration of hAECs did not reduce electrographic or histological brain damage after 30 min of global cerebral ischemia in near-term fetal sheep.
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Affiliation(s)
- Joanne O. Davidson
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland 1010, New Zealand; (L.G.v.d.H.); (S.K.D.); (A.J.G.); (L.B.)
- Correspondence:
| | - Lotte G. van den Heuij
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland 1010, New Zealand; (L.G.v.d.H.); (S.K.D.); (A.J.G.); (L.B.)
| | - Simerdeep K. Dhillon
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland 1010, New Zealand; (L.G.v.d.H.); (S.K.D.); (A.J.G.); (L.B.)
| | - Suzanne L. Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton 3168, Australia; (S.L.M.); (R.L.); (G.J.)
- Department of Obstetrics and Gynaecology, Monash University, Clayton 3800, Australia
| | - Rebecca Lim
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton 3168, Australia; (S.L.M.); (R.L.); (G.J.)
- Department of Obstetrics and Gynaecology, Monash University, Clayton 3800, Australia
| | - Graham Jenkin
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton 3168, Australia; (S.L.M.); (R.L.); (G.J.)
- Department of Obstetrics and Gynaecology, Monash University, Clayton 3800, Australia
| | - Alistair J. Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland 1010, New Zealand; (L.G.v.d.H.); (S.K.D.); (A.J.G.); (L.B.)
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland 1010, New Zealand; (L.G.v.d.H.); (S.K.D.); (A.J.G.); (L.B.)
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7
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Dhillon SK, Gunn ER, Lear BA, King VJ, Lear CA, Wassink G, Davidson JO, Bennet L, Gunn AJ. Cerebral Oxygenation and Metabolism After Hypoxia-Ischemia. Front Pediatr 2022; 10:925951. [PMID: 35903161 PMCID: PMC9314655 DOI: 10.3389/fped.2022.925951] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Perinatal hypoxia-ischemia (HI) is still a significant contributor to mortality and adverse neurodevelopmental outcomes in term and preterm infants. HI brain injury evolves over hours to days, and involves complex interactions between the endogenous protective and pathological processes. Understanding the timing of evolution of injury is vital to guide treatment. Post-HI recovery is associated with a typical neurophysiological profile, with stereotypic changes in cerebral perfusion and oxygenation. After the initial recovery, there is a delayed, prolonged reduction in cerebral perfusion related to metabolic suppression, followed by secondary deterioration with hyperperfusion and increased cerebral oxygenation, associated with altered neurovascular coupling and impaired cerebral autoregulation. These changes in cerebral perfusion are associated with the stages of evolution of injury and injury severity. Further, iatrogenic factors can also affect cerebral oxygenation during the early period of deranged metabolism, and improving clinical management may improve neuroprotection. We will review recent evidence that changes in cerebral oxygenation and metabolism after HI may be useful biomarkers of prognosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Alistair J. Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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8
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Zayachkivsky A, Lehmkuhle MJ, Ekstrand JJ, Dudek FE. Background suppression of electrical activity is a potential biomarker of subsequent brain injury in a rat model of neonatal hypoxia-ischemia. J Neurophysiol 2022; 128:118-130. [PMID: 35675445 DOI: 10.1152/jn.00024.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrographic seizures and abnormal background activity in the neonatal electroencephalogram (EEG) may differentiate between harmful versus benign brain insults. Using two animal models of neonatal seizures, electrical activity was recorded in freely behaving rats and examined quantitatively during successive time periods with field-potential recordings obtained shortly after the brain insult (i.e., 0-4 days). Single-channel, differential recordings with miniature wireless telemetry were used to analyze spontaneous electrographic seizures and background suppression of electrical activity after 1) hypoxia-ischemia (HI), which is a model of neonatal encephalopathy that causes acute seizures and a large brain lesion with possible development of epilepsy, 2) hypoxia alone (Ha), which causes severe acute seizures without an obvious lesion or subsequent epilepsy, and 3) sham control rats. Background EEG exhibited increases in power as a function of age in control animals. Although background electrical activity was depressed in all frequency bands immediately after HI, suppression in the β and γ bands was greatest and lasted longest. Spontaneous electrographic seizures were recorded, but only in a few HI-treated animals. Ha-treated rat pups were similar to sham controls, they had no subsequent spontaneous electrographic seizures after the treatment and background suppression was only briefly observed in one frequency band. Thus, the normal age-dependent maturation of electrical activity patterns in control animals was significantly disrupted after HI. Suppression of the background EEG observed here after HI-induced acute seizures and subsequent brain injury may be a noninvasive biomarker for detecting severe brain injuries and may help predict subsequent epilepsy.NEW & NOTEWORTHY Biomarkers of neonatal brain injury are needed. Hypoxia-ischemia (HI) in immature rat pups caused severe brain injury, which was associated with strongly suppressed background EEG. The suppression was most robust in the β and γ bands; it started immediately after the HI injury and persisted for days. Thus, background suppression may be a noninvasive biomarker for detecting severe brain injuries and may help predict subsequent epilepsy.
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Affiliation(s)
- A Zayachkivsky
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - M J Lehmkuhle
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - J J Ekstrand
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - F E Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
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Lequin MH, Steggerda SJ, Severino M, Tortora D, Parodi A, Ramenghi LA, Groenendaal F, Meys KME, Benders MJNL, de Vries LS, Vann SD. Mammillary body injury in neonatal encephalopathy: a multicentre, retrospective study. Pediatr Res 2022; 92:174-179. [PMID: 33654286 PMCID: PMC9411062 DOI: 10.1038/s41390-021-01436-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND The mammillary bodies (MBs) have repeatedly been shown to be critical for memory, yet little is known about their involvement in numerous neurological conditions linked to memory impairments, including neonatal encephalopathy. METHODS We implemented a multicentre retrospective study, assessing magnetic resonance scans of 219 infants with neonatal encephalopathy who had undergone hypothermia treatment in neonatal intensive care units located in the Netherlands and Italy. RESULTS Abnormal MB signal was observed in ~40% of infants scanned; in half of these cases, the brain appeared otherwise normal. MB involvement was not related to the severity of encephalopathy or the pattern/severity of hypoxic-ischaemic brain injury. Follow-up scans were available for 18 cases with abnormal MB signal; in eight of these cases, the MBs appeared severely atrophic. CONCLUSIONS This study highlights the importance of assessing the status of the MBs in neonatal encephalopathy; this may require changes to scanning protocols to ensure that the slices are sufficiently thin to capture the MBs. Furthermore, long-term follow-up of infants with abnormal MB signal is needed to determine the effects on cognition, which may enable the use of early intervention strategies. Further research is needed to assess the role of therapeutic hypothermia in MB involvement in neonatal encephalopathy. IMPACT The MBs are particularly sensitive to hypoxia in neonates. Current hypothermia treatment provides incomplete protection against MB injury. MB involvement is likely overlooked as it can often occur when the rest of the brain appears normal. Given the importance of the MBs for memory, it is necessary that this region is properly assessed in neonatal encephalopathy. This may require improvements in scanning protocols.
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Affiliation(s)
- Maarten H Lequin
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Sylke J Steggerda
- Department of Neonatology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Domenico Tortora
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Alessandro Parodi
- Neonatal Intensive Care Unit, Department Mother and Child, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Luca A Ramenghi
- Neonatal Intensive Care Unit, Department Mother and Child, IRCCS Istituto Giannina Gaslini, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Floris Groenendaal
- Department of Neonatology, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Karlijn M E Meys
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Manon J N L Benders
- Department of Neonatology, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Linda S de Vries
- Department of Neonatology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Neonatology, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Seralynne D Vann
- School of Psychology, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
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Persistent cortical and white matter inflammation after therapeutic hypothermia for ischemia in near-term fetal sheep. J Neuroinflammation 2022; 19:139. [PMID: 35690757 PMCID: PMC9188214 DOI: 10.1186/s12974-022-02499-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/23/2022] [Indexed: 02/07/2023] Open
Abstract
Background Therapeutic hypothermia significantly improves outcomes after moderate–severe hypoxic-ischemic encephalopathy (HIE), but it is partially effective. Although hypothermia is consistently associated with reduced microgliosis, it is still unclear whether it normalizes microglial morphology and phenotype. Methods Near-term fetal sheep (n = 24) were randomized to sham control, ischemia-normothermia, or ischemia-hypothermia. Brain sections were immunohistochemically labeled to assess neurons, microglia and their interactions with neurons, astrocytes, myelination, and gitter cells (microglia with cytoplasmic lipid granules) 7 days after cerebral ischemia. Lesions were defined as areas with complete loss of cells. RNAscope® was used to assess microglial phenotype markers CD86 and CD206. Results Ischemia-normothermia was associated with severe loss of neurons and myelin (p < 0.05), with extensive lesions, astrogliosis and microgliosis with a high proportion of gitter cells (p < 0.05). Microglial wrapping of neurons was present in both the ischemia groups. Hypothermia improved neuronal survival, suppressed lesions, gitter cells and gliosis (p < 0.05), and attenuated the reduction of myelin area fraction. The “M1” marker CD86 and “M2” marker CD206 were upregulated after ischemia. Hypothermia partially suppressed CD86 in the cortex only (p < 0.05), but did not affect CD206. Conclusions Hypothermia prevented lesions after cerebral ischemia, but only partially suppressed microglial wrapping and M1 marker expression. These data support the hypothesis that persistent upregulation of injurious microglial activity may contribute to partial neuroprotection after hypothermia, and that immunomodulation after rewarming may be an important therapeutic target.
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11
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Lear BA, Lear CA, Dhillon SK, Davidson JO, Bennet L, Gunn AJ. Is late prevention of cerebral palsy in extremely preterm infants plausible? Dev Neurosci 2021; 44:177-185. [PMID: 34937030 DOI: 10.1159/000521618] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 12/16/2021] [Indexed: 11/19/2022] Open
Abstract
Preterm birth continues to be associated with neurodevelopmental problems including cerebral palsy. Cystic white matter injury is still the major neuropathology underlying cerebral palsy, affecting 1-3% of preterm infants. Although rates have gradually fallen over time, the pathogenesis and evolution of cystic white matter injury are still poorly understood. Hypoxia-ischemia (HI) remains an important contributor yet there is no established treatment to prevent injury. Clinically, serial ultrasound and magnetic resonance imaging studies typically show delayed development of cystic lesions 2 to 4 weeks after birth. This raises the important and unresolved question as to whether this represents slow evolution of injury occurring around the time of birth, or repeated injury over many weeks after birth. There is increasing evidence that tertiary injury after HI can contribute to impairment of white and grey matter maturation. In the present review, we discuss preclinical evidence that severe, cystic white matter injury can evolve for many weeks after acute HI and is associated with microglia activity. This suggests the intriguing hypothesis that the tertiary phase of injury is not as subtle as often thought and that there may be a window of therapeutic opportunity for one to two weeks after hypoxic-ischemic injury to prevent delayed cystic lesions and so further reduce the risk of cerebral palsy after preterm birth.
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Affiliation(s)
- Benjamin A Lear
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- 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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12
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Changes in Cellular Localization of Inter-Alpha Inhibitor Proteins after Cerebral Ischemia in the Near-Term Ovine Fetus. Int J Mol Sci 2021; 22:ijms221910751. [PMID: 34639091 PMCID: PMC8509455 DOI: 10.3390/ijms221910751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/17/2021] [Accepted: 09/21/2021] [Indexed: 12/04/2022] Open
Abstract
Inter-alpha Inhibitor Proteins (IAIPs) are key immunomodulatory molecules. Endogenous IAIPs are present in human, rodent, and sheep brains, and are variably localized to the cytoplasm and nuclei at multiple developmental stages. We have previously reported that ischemia-reperfusion (I/R) reduces IAIP concentrations in the fetal sheep brain. In this study, we examined the effect of I/R on total, cytoplasmic, and nuclear expression of IAIPs in neurons (NeuN+), microglia (Iba1+), oligodendrocytes (Olig2+) and proliferating cells (Ki67+), and their co-localization with histones and the endoplasmic reticulum in fetal brain cells. At 128 days of gestation, fetal sheep were exposed to Sham (n = 6) or I/R induced by cerebral ischemia for 30 min with reperfusion for 7 days (n = 5). Although I/R did not change the total number of IAIP+ cells in the cerebral cortex or white matter, cells with IAIP+ cytoplasm decreased, whereas cells with IAIP+ nuclei increased in the cortex. I/R reduced total neuronal number but did not change the IAIP+ neuronal number. The proportion of cytoplasmic IAIP+ neurons was reduced, but there was no change in the number of nuclear IAIP+ neurons. I/R increased the number of microglia and decreased the total numbers of IAIP+ microglia and nuclear IAIP+ microglia, but not the number of cytoplasmic IAIP+ microglia. I/R was associated with reduced numbers of oligodendrocytes and increased proliferating cells, without changes in the subcellular IAIP localization. IAIPs co-localized with the endoplasmic reticulum and histones. In conclusion, I/R alters the subcellular localization of IAIPs in cortical neurons and microglia but not in oligodendrocytes or proliferating cells. Taken together with the known neuroprotective effects of exogenous IAIPs, we speculate that endogenous IAIPs may play a role during recovery from I/R.
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Tetorou K, Sisa C, Iqbal A, Dhillon K, Hristova M. Current Therapies for Neonatal Hypoxic-Ischaemic and Infection-Sensitised Hypoxic-Ischaemic Brain Damage. Front Synaptic Neurosci 2021; 13:709301. [PMID: 34504417 PMCID: PMC8421799 DOI: 10.3389/fnsyn.2021.709301] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/19/2021] [Indexed: 12/15/2022] Open
Abstract
Neonatal hypoxic-ischaemic brain damage is a leading cause of child mortality and morbidity, including cerebral palsy, epilepsy, and cognitive disabilities. The majority of neonatal hypoxic-ischaemic cases arise as a result of impaired cerebral perfusion to the foetus attributed to uterine, placental, or umbilical cord compromise prior to or during delivery. Bacterial infection is a factor contributing to the damage and is recorded in more than half of preterm births. Exposure to infection exacerbates neuronal hypoxic-ischaemic damage thus leading to a phenomenon called infection-sensitised hypoxic-ischaemic brain injury. Models of neonatal hypoxia-ischaemia (HI) have been developed in different animals. Both human and animal studies show that the developmental stage and the severity of the HI insult affect the selective regional vulnerability of the brain to damage, as well as the subsequent clinical manifestations. Therapeutic hypothermia (TH) is the only clinically approved treatment for neonatal HI. However, the number of HI infants needed to treat with TH for one to be saved from death or disability at age of 18-22 months, is approximately 6-7, which highlights the need for additional or alternative treatments to replace TH or increase its efficiency. In this review we discuss the mechanisms of HI injury to the immature brain and the new experimental treatments studied for neonatal HI and infection-sensitised neonatal HI.
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Affiliation(s)
| | | | | | | | - Mariya Hristova
- Perinatal Brain Repair Group, Department of Maternal and Fetal Medicine, UCL Institute for Women’s Health, London, United Kingdom
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Wright JJ, Bourke PD. Combining inter-areal, mesoscopic, and neurodynamic models of cortical function: Response to Commentary on "The growth of cognition: Free energy minimization and the embryogenesis of cortical computation". Phys Life Rev 2021; 39:88-95. [PMID: 34393081 DOI: 10.1016/j.plrev.2021.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 10/20/2022]
Affiliation(s)
- J J Wright
- Centre for Brain Research, and Department of Psychological Medicine, School of Medicine, University of Auckland, Auckland, New Zealand.
| | - P D Bourke
- School of Social Sciences, Faculty of Arts, Business, Law and Education, University of Western Australia, Perth, Australia
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Baburamani AA, Tran NT, Castillo-Melendez M, Yawno T, Walker DW. Brief hypoxia in late gestation sheep causes prolonged disruption of fetal electrographic, breathing behaviours and can result in early labour. J Physiol 2021; 599:3221-3236. [PMID: 33977538 DOI: 10.1113/jp281266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/21/2021] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS Brief episodes of severe fetal hypoxia can arise in late gestation as a result of interruption of normal umbilical blood flow Systemic parameters and blood chemistry indicate complete recovery within 1-2 hours, although the long-term effects on fetal brain functions are unknown Fetal sheep were subjected to umbilical cord occlusion (UCO) for 10 min at 131 days of gestation, and then monitored intensively until onset of labour or delivery (<145 days of gestation) Normal patterns of fetal behaviour, including breathing movements, episodes of high and low voltage electorcortical activity, eye movements and postural (neck) muscle activity, were disrupted for 3-10 days after the UCO Preterm labour and delivery occurred in a significant number of the pregnancies after UCO compared to the control (sham-UCO) cohort. ABSTRACT Complications arising from antepartum events such as impaired umbilical blood flow can cause significant fetal hypoxia. These complications can be unpredictable, as well as difficult to detect, and thus we lack a detailed understanding of the (patho)physiological changes that occur between the antenatal in utero event and birth. In the present study, we assessed the consequences of brief (∼10 min) umbilical cord occlusion (UCO) in fetal sheep at ∼0.88 gestation on fetal plasma cortisol concentrations and fetal behaviour [electrocortical (EcoG), electo-oculargram (EOG), nuchal muscle electromyography (EMG) and breathing activities] in the days following UCO. UCO caused a rapid onset of fetal hypoxaemia, hypercapnia, and acidosis; however, by 6 h, all blood parameters and cardiovascular status were normalized and not different from the control (Sham-UCO) cohort. Subsequently, the incidence of fetal breathing movements decreased compared to the control group, and abnormal behavioural patterns developed over the days following UCO and leading up to the onset of labour, which included increased high voltage and sub-low voltage ECoG and EOG activities, as well as decreased nuchal EMG activity. Fetuses subjected to UCO went into labour 7.9 ± 3.6 days post-UCO (139.5 ± 3.2 days of gestation) compared to the control group fetuses at 13.6 ± 3.3 days post-sham UCO (144 ± 2.2 days of gestation; P < 0.05), despite comparable increases in fetal plasma cortisol and a similar body weight at birth. Thus, a single transient episode of complete UCO late in gestation in fetal sheep can result in prolonged effects on fetal brain activity and premature labour, suggesting persisting effects on fetal cerebral metabolism.
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Affiliation(s)
- Ana A Baburamani
- Department of Perinatal Imaging and Health, Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Nhi T Tran
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia.,The Ritchie Centre, Hudson Institute of Medical Research, and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Margie Castillo-Melendez
- The Ritchie Centre, Hudson Institute of Medical Research, and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Tamara Yawno
- The Ritchie Centre, Hudson Institute of Medical Research, and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
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Maeda Y, Lear CA, Beacom MJ, Davidson JO, Zhou KQ, Gunning M, Ikeda T, Gunn AJ, Bennet L. Transient effects of forebrain ischemia on fetal heart rate variability in fetal sheep. Am J Physiol Regul Integr Comp Physiol 2021; 320:R916-R924. [PMID: 33881362 DOI: 10.1152/ajpregu.00032.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal heart rate variability (FHRV) is a key index of antenatal and intrapartum fetal well-being. FHRV is well established to be mediated by both arms of the autonomic nervous system, but it remains unknown whether higher centers in the forebrain contribute to FHRV. We tested the hypothesis that selective forebrain ischemia would impair the generation of FHRV. Sixteen chronically instrumented near-term fetal sheep were subjected to either forebrain ischemia induced by bilateral carotid occlusion or sham-ischemia for 30 min. Time, frequency, and nonlinear measures of FHRV were assessed during and for seven days after ischemia. Ischemia was associated with profound suppression of electroencephalographic (EEG) power, which remained suppressed throughout the recovery period (P < 0.001). During the first 5 min of ischemia, multiple time and frequency domain measures were increased (all P < 0.05) before returning back to sham levels. A delayed increase in sample entropy was observed during ischemia (P < 0.05). For the first 3 h after ischemia, there was moderate suppression of two measures of FHRV (very-low frequency power and the standard deviation of RR-intervals, both P < 0.05) and increased sample entropy (P < 0.05). Thereafter, all measures of FHRV returned to control levels. In conclusion, profound forebrain ischemia sufficient to lead to severe neural injury had only transient effect on multiple measures of FHRV. These findings suggest that the forebrain makes a limited contribution to FHRV. FHRV therefore primarily originates in the hindbrain and is unlikely to provide meaningful information on forebrain neurodevelopment or metabolism.
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Affiliation(s)
- Yoshiki Maeda
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,The Department of Obstetrics and Gynaecology, Mie University, Mie, Japan
| | - Christopher A Lear
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Michael J Beacom
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Kelly Q Zhou
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Mark Gunning
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Tomoaki Ikeda
- The Department of Obstetrics and Gynaecology, Mie University, Mie, Japan
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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Mitochondrial Dysfunction and Permeability Transition in Neonatal Brain and Lung Injuries. Cells 2021; 10:cells10030569. [PMID: 33807810 PMCID: PMC7999701 DOI: 10.3390/cells10030569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 01/16/2023] Open
Abstract
This review discusses the potential mechanistic role of abnormally elevated mitochondrial proton leak and mitochondrial bioenergetic dysfunction in the pathogenesis of neonatal brain and lung injuries associated with premature birth. Providing supporting evidence, we hypothesized that mitochondrial dysfunction contributes to postnatal alveolar developmental arrest in bronchopulmonary dysplasia (BPD) and cerebral myelination failure in diffuse white matter injury (WMI). This review also analyzes data on mitochondrial dysfunction triggered by activation of mitochondrial permeability transition pore(s) (mPTP) during the evolution of perinatal hypoxic-ischemic encephalopathy. While the still cryptic molecular identity of mPTP continues to be a subject for extensive basic science research efforts, the translational significance of mitochondrial proton leak received less scientific attention, especially in diseases of the developing organs. This review is focused on the potential mechanistic relevance of mPTP and mitochondrial dysfunction to neonatal diseases driven by developmental failure of organ maturation or by acute ischemia-reperfusion insult during development.
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Lear CA, Kasai M, Drury PP, Davidson JO, Miyagi E, Bennet L, Gunn AJ. Plasma vasopressin levels are closely associated with fetal hypotension and neuronal injury after hypoxia-ischemia in near-term fetal sheep. Pediatr Res 2020; 88:857-864. [PMID: 32179873 DOI: 10.1038/s41390-020-0845-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/11/2020] [Accepted: 02/17/2020] [Indexed: 01/14/2023]
Abstract
BACKGROUND Sensitive biomarkers are needed to rapidly identify high-risk infants after hypoxia-ischemia for neuroprotective treatment. Hypotension is a key determinant of hypoxic-ischemic neural injury, and a potent stimulus of humoral pressors including angiotensin-II and arginine vasopressin. We therefore aimed to quantify the relationship between vasopressin and angiotensin-II levels in the latent phase after hypoxia-ischemia induced by umbilical cord occlusion (UCO) with both the severity of preceding hypotension and subsequent neuronal injury. METHODS Chronically instrumented near-term fetal sheep underwent sham-UCO or UCO for either 15 min or until mean arterial pressure was <8 mmHg. Neuronal injury was assessed after 72 h recovery. RESULTS Umbilical cord occlusion was associated with severe hypotension that recovered after UCO; two fetuses developed profound secondary hypotension within 6 h and died. Vasopressin levels but not angiotensin-II were significantly elevated 1-3 h after UCO and were closely associated with the severity of hypotension during UCO and the subsequent severity of neuronal loss in the parasagittal and lateral cortex, caudate nucleus and putamen. The Youden cut-point for vasopressin at 1 h was 180.0 pmol/L, with sensitivity 100% and specificity 92.3% for severe neuronal injury or death. CONCLUSION Vasopressin levels shortly after moderate-severe hypoxia-ischemia may be a useful early biomarker to guide the timely implementation of neuroprotective treatment. IMPACT It can be difficuIt to rapidly identify infants who might benefit from therapeutic hypothermia. We investigated whether increases in plasma pressor hormones early after hypoxia-ischemia were biomarkers for neonatal hypoxic-ischemic encephalopathy using near-term fetal sheep. Arginine vasopressin levels were elevated at 1-3 h after hypoxia-ischemia and were predictive of the severity of preceding hypotension and subsequent risk of severe neuronal injury or death after hypoxia-ischemia. Arginine vasopressin may help identify neonates at high risk of hypoxic-ischemic encephalopathy early within the therapeutic window for hypothermia.
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Affiliation(s)
- Christopher A Lear
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Michi Kasai
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,The Department of Obstetrics and Gynecology, Yokohama City University, Yokohama, Japan
| | - Paul P Drury
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Etsuko Miyagi
- The Department of Obstetrics and Gynecology, Yokohama City University, Yokohama, Japan
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
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Bhattacharya S, Bennet L, Davidson JO, Unsworth CP. A novel approach to segment cortical neurons in histological images of the near-term fetal sheep brain model. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:1051-1054. [PMID: 33018166 DOI: 10.1109/embc44109.2020.9176734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Oxygen deprivation (hypoxia) and reduced blood supply (ischemia) can occur before, during or shortly after birth and can result in death, brain damage and long-term disability. Assessing neuronal survival after hypoxia-ischemia in the near-term fetal sheep brain model is essential for the development of novel treatment strategies. As manual quantification of neurons in histological images varies between different assessors and is extremely time-consuming, automation of the process is needed and has not been currently achieved. To achieve automation, successfully segmenting the neurons from the background is very important. Due to presence of densely populated overlapping cells and with no prior information of shapes and sizes, the segmentation of neurons from the image is complex. Initially, we segmented the RGB images by using K-means clustering to primarily segment the neurons from the background based on their colour value, a distance transform for seed detection and watershed method for separating overlapping objects. However, this resulted in unsatisfactory sensitivity and performance due to over-segmentation if we use the RGB image directly. In this paper, we propose a semi-automated modified approach to segment neurons that tackles the over-segmentation issue that we encountered. Initially, we separated the red, green and blue colour channel information from the RGB image. We determined that by applying the same segmentation method first to the blue channel image, then by performing segmentation on the green channel for the neurons that remain unsegmented from the blue channel segmentation and finally by performing segmentation on red channel for neurons that were still unsegmented from the green channel segmentation, improved performance results could be achieved. The modified approach increased performance for the healthy and ischemic animal images from 89.7% to 98.08% and from 94.36% to 98.06% respectively as compared to using RGB image directly.
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How to Improve the Antioxidant Defense in Asphyxiated Newborns-Lessons from Animal Models. Antioxidants (Basel) 2020; 9:antiox9090898. [PMID: 32967335 PMCID: PMC7554981 DOI: 10.3390/antiox9090898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/12/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Oxygen free radicals have been implicated in brain damage after neonatal asphyxia. In the early phase of asphyxia/reoxygenation, changes in antioxidant enzyme activity play a pivotal role in switching on and off the cascade of events that can kill the neurons. Hypoxia/ischemia (H/I) forces the brain to activate endogenous mechanisms (e.g., antioxidant enzymes) to compensate for the lost or broken neural circuits. It is important to evaluate therapies to enhance the self-protective capacity of the brain. In animal models, decreased body temperature during neonatal asphyxia has been shown to increase cerebral antioxidant capacity. However, in preterm or severely asphyxiated newborns this therapy, rather than beneficial seems to be harmful. Thus, seeking new therapeutic approaches to prevent anoxia-induced complications is crucial. Pharmacotherapy with deferoxamine (DFO) is commonly recognized as a beneficial regimen for H/I insult. DFO, via iron chelation, reduces oxidative stress. It also assures an optimal antioxidant protection minimizing depletion of the antioxidant enzymes as well as low molecular antioxidants. In the present review, some aspects of recently acquired insight into the therapeutic effects of hypothermia and DFO in promoting neuronal survival after H/I are discussed.
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21
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Connexin Hemichannel Mimetic Peptide Attenuates Cortical Interneuron Loss and Perineuronal Net Disruption Following Cerebral Ischemia in Near-Term Fetal Sheep. Int J Mol Sci 2020; 21:ijms21186475. [PMID: 32899855 PMCID: PMC7554896 DOI: 10.3390/ijms21186475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/19/2022] Open
Abstract
Perinatal hypoxia-ischemia is associated with disruption of cortical gamma-aminobutyric acid (GABA)ergic interneurons and their surrounding perineuronal nets, which may contribute to persisting neurological deficits. Blockade of connexin43 hemichannels using a mimetic peptide can alleviate seizures and injury after hypoxia-ischemia. In this study, we tested the hypothesis that connexin43 hemichannel blockade improves the integrity of cortical interneurons and perineuronal nets. Term-equivalent fetal sheep received 30 min of bilateral carotid artery occlusion, recovery for 90 min, followed by a 25-h intracerebroventricular infusion of vehicle or a mimetic peptide that blocks connexin hemichannels or by a sham ischemia + vehicle infusion. Brain tissues were stained for interneuronal markers or perineuronal nets. Cerebral ischemia was associated with loss of cortical interneurons and perineuronal nets. The mimetic peptide infusion reduced loss of glutamic acid decarboxylase-, calretinin-, and parvalbumin-expressing interneurons and perineuronal nets. The interneuron and perineuronal net densities were negatively correlated with total seizure burden after ischemia. These data suggest that the opening of connexin43 hemichannels after perinatal hypoxia-ischemia causes loss of cortical interneurons and perineuronal nets and that this exacerbates seizures. Connexin43 hemichannel blockade may be an effective strategy to attenuate seizures and may improve long-term neurological outcomes after perinatal hypoxia-ischemia.
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Xiao X, Tang Y, Wooff Y, Su C, Kang M, O'Carroll SJ, Chen Q, Chamley L. Upregulation of pannexin-1 hemichannels explains the apparent death of the syncytiotrophoblast during human placental explant culture. Placenta 2020; 94:1-12. [PMID: 32217265 DOI: 10.1016/j.placenta.2020.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 02/19/2020] [Accepted: 03/02/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND It has been reported that during the culture of human placental explants, the syncytiotrophoblast dies between 3 and 24 h and is then replaced within 48 h by a new syncytiotrophoblast layer formed by the fusion of underlying cytotrophoblasts. Most frequently the death of the syncytiotrophoblast is indicated by the uptake of nuclear stains such as propidium iodide (PI). This process is reportedly similar in both early and late gestation placental explants. METHODS We cultured first trimester placental explants for up to 48 h and tested membrane intactness by exposure to PI. Connexin and pannexin mRNAs were quantified by RT-PCR and protein levels determined by immunofluorescence. The syncytiotrophoblast membrane leak was determined by culturing explants in the presence of hemichannel blockers. Extrusion of extracellular vesicles from the syncytiotrophoblast was quantified. RESULTS Nuclei of the syncytiotrophoblast were stained with PI following approximately 4 h of culture and this was prevented by culturing the explants with pannexin-1 blockers. Expression of pannexin-1 hemichannels increased during explant culture (p = 0.0027). Extracellular vesicles were most abundantly extruded from the explants during the first 3 h of culture and the temporal pattern of extrusion was unaltered by blocking hemichannels. DISCUSSION We show the mechanism of uptake of nuclear non-viability stains into the syncytiotrophoblast during explant culture is via upregulation of pannexin 1 hemichannels. Contrary to suggestions by some, the production of extracellular vesicles from cultured placental explants is not an in vitro artefact resulting from the apparent death of the syncytiotrophoblast in explant cultures.
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Affiliation(s)
- Xirong Xiao
- The Hospital of Obstetrics and Gynaecology, Fudan University, Shanghai, China; Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Yunhui Tang
- The Hospital of Obstetrics and Gynaecology, Fudan University, Shanghai, China; Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Yvette Wooff
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Chunlin Su
- The Hospital of Obstetrics and Gynaecology, Fudan University, Shanghai, China; Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Matt Kang
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Qi Chen
- The Hospital of Obstetrics and Gynaecology, Fudan University, Shanghai, China; Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand.
| | - Larry Chamley
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
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Wassink G, Davidson JO, Fraser M, Yuill CA, Bennet L, Gunn AJ. Non-additive effects of adjunct erythropoietin therapy with therapeutic hypothermia after global cerebral ischaemia in near-term fetal sheep. J Physiol 2020; 598:999-1015. [PMID: 31912503 DOI: 10.1113/jp279131] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/02/2020] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Recombinant human erythropoietin (rEpo) is neuroprotective in immature animals, but it is unclear whether the combination of high-dose rEpo therapy with therapeutic hypothermia can further improve outcomes. Hypothermia and rEpo independently improved neuronal survival, with greater improvement with hypothermia, and similarly reduced numbers of caspase-3 positive cells and reactive microglia after 7 days recovery. Hypothermia, but not rEpo, was associated with markedly improved EEG power, whereas both interventions improved recovery of EEG frequency. There was no significant improvement in any outcome after combined rEpo and hypothermia compared with hypothermia alone, and of concern, the combination was associated with increased numbers of cortical caspase-3-positive cells compared with ischaemia-hypothermia. These data suggest that the mechanisms of neuroprotection with hypothermia and rEpo overlap and, thus, high-dose rEpo infusion does not appear to be an effective adjunct therapy for therapeutic hypothermia. ABSTRACT Therapeutic hypothermia for hypoxic-ischaemic encephalopathy (HIE) provides incomplete neuroprotection. Recombinant human erythropoietin (rEpo) is neuroprotective in immature animals, but it is unclear whether adjunct rEpo therapy with therapeutic hypothermia can further improve outcomes. Near-term fetal sheep received sham-ischaemia (n = 9) or global cerebral ischaemia for 30 min (ischaemia-vehicle, n = 8), followed by intravenous infusion of rEpo (ischaemia-Epo, n = 8; 5000 U/kg loading dose, then 833.3 U/kg/h), cerebral hypothermia (ischaemia-hypothermia, n = 8), or rEpo plus hypothermia (ischaemia-Epo-hypothermia, n = 8), from 3 to 72 h post ischaemia. Fetal brains were collected 7 days after cerebral ischaemia. Cerebral ischaemia was associated with severe neuronal loss and microglial induction in the parasagittal cortex and subcortical regions. Hypothermia reduced overall neuronal loss, cortical caspase-3 and reactive microglia in the striatum and cortex, with greater recovery of electroencephalographic (EEG) power and spectral edge (SEF) from 48 h onwards. rEpo independently improved neuronal survival in the parasagittal cortex, hippocampal CA4 and thalamus, and reduced cortical caspase-3 and activated microglia in striatal and cortical areas, with greater SEF from 120 h onwards. However, ischaemia-Epo-hypothermia did not further improve outcomes compared with ischaemia-hypothermia and was associated with increased numbers of cortical caspase-3-positive cells. These findings suggest that although delayed, prolonged treatment with both hypothermia and rEpo are independently neuroprotective, they have overlapping anti-inflammatory and anti-apoptotic mechanisms, such that the delayed, high-dose rEpo infusion for 3 days did not materially augment neuroprotection with therapeutic hypothermia.
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Affiliation(s)
- Guido Wassink
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, New Zealand
| | - Joanne O Davidson
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, New Zealand
| | - Mhoyra Fraser
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, New Zealand
| | - Caroline A Yuill
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, New Zealand
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, New Zealand
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Montaldo P, Ivain P, Lally P, Bassett P, Pant S, Oliveira V, Mendoza J, Morales M, Swamy R, Shankaran S, Thayyil S. White matter injury after neonatal encephalopathy is associated with thalamic metabolite perturbations. EBioMedicine 2020; 52:102663. [PMID: 32062359 PMCID: PMC7016374 DOI: 10.1016/j.ebiom.2020.102663] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Although thalamic magnetic resonance (MR) spectroscopy (MRS) accurately predicts adverse outcomes after neonatal encephalopathy, its utility in infants without MR visible deep brain nuclei injury is not known. We examined thalamic MRS metabolite perturbations in encephalopathic infants with white matter (WM) injury with or without cortical injury and its associations with adverse outcomes. METHODS We performed a subgroup analysis of all infants recruited to the MARBLE study with isolated WM or mixed WM/cortical injury, but no visible injury to the basal ganglia/thalamus (BGT) or posterior limb of the internal capsule (PLIC). We used binary logistic regression to examine the association of MRS biomarkers with three outcomes (i) WM injury score (1 vs. 2/3); (ii) cortical injury scores (0/1 vs. 2/3); and (iii) adverse outcomes (defined as death, moderate/severe disability) at two years (yes/no). We also assessed the accuracy of MRS for predicting adverse outcome. FINDINGS Of the 107 infants included in the analysis, five had adverse outcome. Reduced thalamic N-acetylaspartate concentration [NAA] (odds ratio 0.4 (95% CI 0.18-0.93)) and elevated thalamic Lactate/NAA peak area ratio (odds ratio 3.37 (95% CI 1.45-7.82)) were significantly associated with higher WM injury scores, but not with cortical injury. Thalamic [NAA] (≤5.6 mmol/kg/wet weight) had the best accuracy for predicting adverse outcomes (sensitivity 1.00 (95% CI 0.16-1.00); specificity 0.95 (95% CI 0.84-0.99)). INTERPRETATION Thalamic NAA is reduced in encephalopathic infants without MR visible deep brain nuclei injury and may be a useful predictor of adverse outcomes. FUNDING The National Institute for Health Research (NIHR).
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Affiliation(s)
- Paolo Montaldo
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK; Department of Neonatal Intensive Care, Università degli Studi della Campania Luigi Vanvitelli, Naples, Italy.
| | - Phoebe Ivain
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Pete Lally
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | | | - Stuti Pant
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Vania Oliveira
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Josephine Mendoza
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Maria Morales
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Ravi Swamy
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | | | - Sudhin Thayyil
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
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Abbasi H, Unsworth CP. Electroencephalogram studies of hypoxic ischemia in fetal and neonatal animal models. Neural Regen Res 2020; 15:828-837. [PMID: 31719243 PMCID: PMC6990791 DOI: 10.4103/1673-5374.268892] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alongside clinical achievements, experiments conducted on animal models (including primate or non-primate) have been effective in the understanding of various pathophysiological aspects of perinatal hypoxic/ischemic encephalopathy (HIE). Due to the reasonably fair degree of flexibility with experiments, most of the research around HIE in the literature has been largely concerned with the neurodevelopmental outcome or how the frequency and duration of HI seizures could relate to the severity of perinatal brain injury, following HI insult. This survey concentrates on how EEG experimental studies using asphyxiated animal models (in rodents, piglets, sheep and non-human primate monkeys) provide a unique opportunity to examine from the exact time of HI event to help gain insights into HIE where human studies become difficult.
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Affiliation(s)
- Hamid Abbasi
- Department of Engineering Science, the University of Auckland, Auckland, New Zealand
| | - Charles P Unsworth
- Department of Engineering Science, the University of Auckland, Auckland, New Zealand
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26
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Volpe JJ. Placental assessment provides insight into mechanisms and timing of neonatal hypoxic-ischemic encephalopathy. J Neonatal Perinatal Med 2019; 12:113-116. [PMID: 31256081 PMCID: PMC6597972 DOI: 10.3233/npm-190270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Joseph J Volpe
- Department of Neurology, Harvard Medical School, Boston, MA, USA.,Department of Pediatric Newborn Medicine, Harvard Medical School, Boston, MA, USA
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27
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Davidson JO, Wassink G, Draghi V, Dhillon SK, Bennet L, Gunn AJ. Limited benefit of slow rewarming after cerebral hypothermia for global cerebral ischemia in near-term fetal sheep. J Cereb Blood Flow Metab 2019; 39:2246-2257. [PMID: 30092709 PMCID: PMC6827112 DOI: 10.1177/0271678x18791631] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The optimal rate of rewarming after therapeutic hypothermia for neonatal hypoxic-ischemic encephalopathy is unknown, although it is widely suggested that slow rewarming is beneficial. Some preclinical studies suggest better outcomes with slower rewarming, but did not control for the duration of hypothermia. In this study, near-term fetal sheep (0.85 gestation) received 30 min cerebral ischemia followed by normothermia, 48 h hypothermia with rapid rewarming over 1 h, 48-h hypothermia with slow rewarming over 24 h, or 72-h hypothermia with rapid rewarming. Slow rewarming after 48 h of hypothermia improved recovery of EEG power compared with rapid rewarming (p < 0.05), but was not different from rapid rewarming after 72 h of hypothermia. At seven days recovery, neuronal survival was partially improved by both fast and slow rewarming after 48-h hypothermia, but less than 72-h hypothermia in the cortex and CA4 (p < 0.05). In conclusion, although electrographic recovery was partially improved by slow rewarming over 24 h following cerebral hypothermia for 48 h, optimal neuroprotection was seen with hypothermia for 72 h with rapid rewarming, suggesting that the overall duration of cooling was the critical determinant of outcomes after therapeutic hypothermia.
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Affiliation(s)
- Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Vittoria Draghi
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | | | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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28
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Cavarsan CF, Gorassini MA, Quinlan KA. Animal models of developmental motor disorders: parallels to human motor dysfunction in cerebral palsy. J Neurophysiol 2019; 122:1238-1253. [PMID: 31411933 PMCID: PMC6766736 DOI: 10.1152/jn.00233.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
Cerebral palsy (CP) is the most common motor disability in children. Much of the previous research on CP has focused on reducing the severity of brain injuries, whereas very few researchers have investigated the cause and amelioration of motor symptoms. This research focus has had an impact on the choice of animal models. Many of the commonly used animal models do not display a prominent CP-like motor phenotype. In general, rodent models show anatomically severe injuries in the central nervous system (CNS) in response to insults associated with CP, including hypoxia, ischemia, and neuroinflammation. Unfortunately, most rodent models do not display a prominent motor phenotype that includes the hallmarks of spasticity (muscle stiffness and hyperreflexia) and weakness. To study motor dysfunction related to developmental injuries, a larger animal model is needed, such as rabbit, pig, or nonhuman primate. In this work, we describe and compare various animal models of CP and their potential for translation to the human condition.
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Affiliation(s)
- Clarissa F Cavarsan
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island
| | - Monica A Gorassini
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Katharina A Quinlan
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island
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29
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Montaldo P, Lally PJ, Oliveira V, Swamy R, Mendoza J, Atreja G, Kariholu U, Shivamurthappa V, Liow N, Teiserskas J, Pryce R, Soe A, Shankaran S, Thayyil S. Therapeutic hypothermia initiated within 6 hours of birth is associated with reduced brain injury on MR biomarkers in mild hypoxic-ischaemic encephalopathy: a non-randomised cohort study. Arch Dis Child Fetal Neonatal Ed 2019; 104:F515-F520. [PMID: 30425113 PMCID: PMC6788875 DOI: 10.1136/archdischild-2018-316040] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To examine the effect of therapeutic hypothermia on MR biomarkers and neurodevelopmental outcomes in babies with mild hypoxic-ischaemic encephalopathy (HIE). DESIGN Non-randomised cohort study. SETTING Eight tertiary neonatal units in the UK and the USA. PATIENTS 47 babies with mild HIE on NICHD neurological examination performed within 6 hours after birth. INTERVENTIONS Whole-body cooling for 72 hours (n=32) or usual care (n=15; of these 5 were cooled for <12 hours). MAIN OUTCOME MEASURES MRI and MR spectroscopy (MRS) within 2 weeks after birth, and a neurodevelopmental outcome assessment at 2 years. RESULTS The baseline characteristics in both groups were similar except for lower 10 min Apgar scores (p=0.02) in the cooled babies. Despite this, the mean (SD) thalamic NAA/Cr (1.4 (0.1) vs 1.6 (0.2); p<0.001) and NAA/Cho (0.67 (0.08) vs 0.89 (0.11); p<0.001) ratios from MRS were significantly higher in the cooled group. Cooled babies had lower white matter injury scores than non-cooled babies (p=0.02). Four (27%) non-cooled babies with mild HIE developed seizures after 6 hours of age, while none of the cooled babies developed seizures (p=0.008). Neurodevelopmental outcomes at 2 years were available in 40 (85%) of the babies. Adverse outcomes were seen in 2 (14.3%) non-cooled babies, and none of the cooled babies (p=0.09). CONCLUSIONS Therapeutic hypothermia may have a neuroprotective effect in babies with mild HIE, as demonstrated by improved MRS biomarkers and reduced white matter injury on MRI. This may warrant further evaluation in adequately powered randomised controlled trials.
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Affiliation(s)
- Paolo Montaldo
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Peter J Lally
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Vânia Oliveira
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Ravi Swamy
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Josephine Mendoza
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Gaurav Atreja
- Neonatal Unit, Imperial Healthcare NHS Trust, London, UK
| | - Ujwal Kariholu
- Neonatal Unit, Imperial Healthcare NHS Trust, London, UK
| | | | - Natasha Liow
- Neonatal Unit, Imperial Healthcare NHS Trust, London, UK
| | | | - Russell Pryce
- Oliver Fisher Neonatal Unit, Medway NHS Hospital Foundation Trust, Gillingham, UK
| | - Aung Soe
- Oliver Fisher Neonatal Unit, Medway NHS Hospital Foundation Trust, Gillingham, UK
| | - Seetha Shankaran
- Perinatal-Neonatal Medicine, Wayne State University, Detroit, Michigan, USA
| | - Sudhin Thayyil
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
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30
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Draghi V, Wassink G, Zhou KQ, Bennet L, Gunn AJ, Davidson JO. Differential effects of slow rewarming after cerebral hypothermia on white matter recovery after global cerebral ischemia in near-term fetal sheep. Sci Rep 2019; 9:10142. [PMID: 31300687 PMCID: PMC6626025 DOI: 10.1038/s41598-019-46505-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/27/2019] [Indexed: 12/27/2022] Open
Abstract
It is widely believed that rewarming slowly after therapeutic hypothermia for hypoxic-ischemic (HI) encephalopathy can improve outcomes, but its impact on white matter injury after HI is unclear. Fetal sheep (0.85 gestation) received 30 min ischemia-normothermia (n = 8), or hypothermia from 3–48 h with rapid spontaneous rewarming over 1 h (ischemia-48 h hypothermia, n = 8), or 48 h with slow rewarming over 24 h (ischemia-slow rewarming, n = 7) or 72 h with rapid rewarming (ischemia-72 h hypothermia, n = 8). Ischemia was associated with loss of total and mature oligodendrocytes and reduced area fraction of myelin basic protein (MBP) and 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase; immature/mature oligodendrocytes) and increased microglia and astrocytes. Total numbers of oligodendrocytes were increased by all hypothermia protocols but only ischemia-72 h hypothermia attenuated loss of mature oligodendrocytes. All hypothermia protocols similarly increased the area fraction of MBP, whereas there was only an intermediate effect on the area fraction of CNPase. Microglia were suppressed by all hypothermia protocols, with the greatest reduction after ischemia-72 h hypothermia, and an intermediate effect after ischemia-slow rewarming. By contrast, induction of astrocytes was significantly reduced only after ischemia-slow rewarming. In conclusion, slow rewarming after hypothermia did not improve oligodendrocyte survival or myelination or suppression of microgliosis compared to fast rewarming, but modestly reduced astrocytosis.
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Affiliation(s)
- V Draghi
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - G Wassink
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - K Q Zhou
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - L Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - A J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand.
| | - J O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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31
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Murray SJ, Black BL, Reid SJ, Rudiger SR, Simon Bawden C, Snell RG, Waldvogel HJ, Faull RL. Chemical neuroanatomy of the substantia nigra in the ovine brain. J Chem Neuroanat 2019; 97:43-56. [DOI: 10.1016/j.jchemneu.2019.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/20/2023]
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32
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Wu L, Zhao H, Weng H, Ma D. Lasting effects of general anesthetics on the brain in the young and elderly: "mixed picture" of neurotoxicity, neuroprotection and cognitive impairment. J Anesth 2019; 33:321-335. [PMID: 30859366 PMCID: PMC6443620 DOI: 10.1007/s00540-019-02623-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/04/2019] [Indexed: 12/22/2022]
Abstract
General anesthetics are commonly used in major surgery. To achieve the depth of anesthesia for surgery, patients are being subjected to a variety of general anesthetics, alone or in combination. It has been long held an illusory concept that the general anesthesia is entirely reversible and that the central nervous system is returned to its pristine state once the anesthetic agent is eliminated from the active site. However, studies indicate that perturbation of the normal functioning of these targets may result in long-lasting desirable or undesirable effects. This review focuses on the impact of general anesthetic exposure to the brain and summarizes the molecular and cellular mechanisms by which general anesthetics may induce long-lasting undesirable effects when exposed at the developing stage of the brain. The vulnerability of aging brain to general anesthetics, specifically in the context of cognitive disorders and Alzheimer’s disease pathogeneses are also discussed. Moreover, we will review emerging evidence regarding the neuroprotective property of xenon and anesthetic adjuvant dexmedetomidine in the immature and mature brains. In conclusion, “mixed picture” effects of general anesthetics should be well acknowledged and should be implemented into daily clinical practice for better patient outcome.
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Affiliation(s)
- Lingzhi Wu
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, UK
| | - Hailin Zhao
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, UK
| | - Hao Weng
- Department of Anesthesiology, Shanghai Fengxian District Central Hospital, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Fengxian District, Shanghai, China
| | - Daqing Ma
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, UK.
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33
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Should therapeutic hypothermia be offered to babies with mild neonatal encephalopathy in the first 6 h after birth? Pediatr Res 2019; 85:442-448. [PMID: 30733613 DOI: 10.1038/s41390-019-0291-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/20/2018] [Accepted: 12/30/2018] [Indexed: 12/11/2022]
Abstract
Infants with moderate to severe neonatal encephalopathy (NE) benefit significantly from therapeutic hypothermia, with reduced risk of death or disability. However, the need for therapeutic hypothermia for infants with milder NE remains unclear. It has been suggested that these infants should not be offered therapeutic hypothermia as they may not be at risk for adverse neurodevelopmental outcome and that the balance of risk against potential benefit is unknown. Several key questions need to be answered including first, whether one can define NE in the first 6 h after birth so as to accurately distinguish infants with brain injury who may be at risk for adverse neurodevelopmental consequences. Second, will treatment of infants with mild NE with therapeutic hypothermia improve or even worsen neurological outcomes? Although alternate treatment protocols for mild NE may be feasible, the use of the current approach combined with rigorous avoidance of hyperthermia and initiation of hypothermia as early as possible after birth may promote optimal outcomes. Animal experimental data support the potential for greater benefit for mild HIE compared with moderate to severe HIE. This review will summarize current knowledge of mild NE and the challenges to a trial in this population.
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34
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Zhou KQ, Green CR, Bennet L, Gunn AJ, Davidson JO. The Role of Connexin and Pannexin Channels in Perinatal Brain Injury and Inflammation. Front Physiol 2019; 10:141. [PMID: 30873043 PMCID: PMC6400979 DOI: 10.3389/fphys.2019.00141] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/07/2019] [Indexed: 12/21/2022] Open
Abstract
Perinatal brain injury remains a major cause of death and life-long disability. Perinatal brain injury is typically associated with hypoxia-ischemia and/or infection/inflammation. Both hypoxia-ischemia and infection trigger an inflammatory response in the brain. The inflammatory response can contribute to brain cell loss and chronic neuroinflammation leading to neurological impairments. It is now well-established that brain injury evolves over time, and shows a striking spread from injured to previously uninjured regions of the brain. There is increasing evidence that this spread is related to opening of connexin hemichannels and pannexin channels, both of which are large conductance membrane channels found in almost all cell types in the brain. Blocking connexin hemichannels within the first 3 h after hypoxia-ischemia has been shown to improve outcomes in term equivalent fetal sheep but it is important to also understand the downstream pathways linking membrane channel opening with the development of injury in order to identify new therapeutic targets. Open membrane channels release adenosine triphosphate (ATP), and other neuroactive molecules, into the extracellular space. ATP has an important physiological role, but has also been reported to act as a damage-associated molecular pattern (DAMP) signal mediated through specific purinergic receptors and so act as a primary signal 1 in the innate immune system inflammasome pathway. More crucially, extracellular ATP is a key inflammasome signal 2 activator, with purinergic receptor binding triggering the assembly of the multi-protein inflammasome complex. The inflammasome pathway and complex formation contribute to activation of inflammatory caspases, and the release of inflammatory cytokines, including interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-18, and vascular endothelial growth factor (VEGF). We propose that the NOD-like receptor protein-3 (NLRP3) inflammasome, which has been linked to inflammatory responses in models of ischemic stroke and various inflammatory diseases, may be one mechanism by which connexin hemichannel opening especially mediates perinatal brain injury.
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Affiliation(s)
- Kelly Q Zhou
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
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35
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Wassink G, Davidson JO, Dhillon SK, Zhou K, Bennet L, Thoresen M, Gunn AJ. Therapeutic Hypothermia in Neonatal Hypoxic-Ischemic Encephalopathy. Curr Neurol Neurosci Rep 2019; 19:2. [PMID: 30637551 DOI: 10.1007/s11910-019-0916-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW Therapeutic hypothermia reduces death or disability in term and near-term infants with moderate-severe hypoxic-ischemic encephalopathy. Nevertheless, many infants still survive with disability, despite hypothermia, supporting further research in to ways to further improve neurologic outcomes. RECENT FINDINGS Recent clinical and experimental studies have refined our understanding of the key parameters for hypothermic neuroprotection, including timing of initiation, depth, and duration of hypothermia, and subsequent rewarming rate. However, important knowledge gaps remain. There is encouraging clinical evidence from a small phase II trial that combined treatment of hypothermia with recombinant erythropoietin further reduces risk of disability but definitive studies are still needed. In conclusion, recent studies suggest that current protocols for therapeutic hypothermia are near-optimal, and that the key to better neurodevelopmental outcomes is earlier diagnosis and initiation of hypothermia after birth. Further research is essential to find and evaluate ways to further improve outcomes after hypoxic-ischemic encephalopathy, including add-on therapies for therapeutic hypothermia and preventing pyrexia during labor and delivery.
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Affiliation(s)
- Guido Wassink
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Joanne O Davidson
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Simerdeep K Dhillon
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Kelly Zhou
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Laura Bennet
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Marianne Thoresen
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Neonatal Neuroscience, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Alistair J Gunn
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag, Auckland, 92019, New Zealand.
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36
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Loss of interneurons and disruption of perineuronal nets in the cerebral cortex following hypoxia-ischaemia in near-term fetal sheep. Sci Rep 2018; 8:17686. [PMID: 30523273 PMCID: PMC6283845 DOI: 10.1038/s41598-018-36083-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/15/2018] [Indexed: 11/29/2022] Open
Abstract
Hypoxia-ischaemia (HI) in term infants is a common cause of brain injury and neurodevelopmental impairment. Development of gamma-aminobutyric acid (GABA)ergic circuitry in the cerebral cortex is a critical event in perinatal brain development. Perineuronal nets (PNNs) are specialised extracellular matrix structures that surround GABAergic interneurons, and are important for their function. Herein, we hypothesised that HI would reduce survival of cortical interneurons and disrupt PNNs in a near-term fetal sheep model of global cerebral ischaemia. Fetal sheep (0.85 gestation) received sham occlusion (n = 5) or 30 min of reversible cerebral ischaemia (HI group; n = 5), and were recovered for 7 days. Expression of interneurons (glutamate decarboxylase [GAD]+; parvalbumin [PV]+) and PNNs (Wisteria floribunda agglutinin, WFA) was assessed in the parasagittal cortex by immunohistochemistry. HI was associated with marked loss of both GAD+ and PV+ cortical interneurons (all layers of the parasagittal cortex and layer 6) and PNNs (layer 6). The expression and integrity of PNNs was also reduced on surviving GAD+ interneurons. There was a trend towards a linear correlation of the proportion of GAD+ neurons that were WFA+ with seizure burden (r2 = 0.76, p = 0.0534). Overall, these data indicate that HI may cause deficits in the cortical GABAergic system involving loss of interneurons and disruption of PNNs, which may contribute to the range of adverse neurological outcomes following perinatal brain injury.
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37
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Koehler RC, Yang ZJ, Lee JK, Martin LJ. Perinatal hypoxic-ischemic brain injury in large animal models: Relevance to human neonatal encephalopathy. J Cereb Blood Flow Metab 2018; 38:2092-2111. [PMID: 30149778 PMCID: PMC6282216 DOI: 10.1177/0271678x18797328] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Perinatal hypoxia-ischemia resulting in death or lifelong disabilities remains a major clinical disorder. Neonatal models of hypoxia-ischemia in rodents have enhanced our understanding of cellular mechanisms of neural injury in developing brain, but have limitations in simulating the range, accuracy, and physiology of clinical hypoxia-ischemia and the relevant systems neuropathology that contribute to the human brain injury pattern. Large animal models of perinatal hypoxia-ischemia, such as partial or complete asphyxia at the time of delivery of fetal monkeys, umbilical cord occlusion and cerebral hypoperfusion at different stages of gestation in fetal sheep, and severe hypoxia and hypoperfusion in newborn piglets, have largely overcome these limitations. In monkey, complete asphyxia produces preferential injury to cerebellum and primary sensory nuclei in brainstem and thalamus, whereas partial asphyxia produces preferential injury to somatosensory and motor cortex, basal ganglia, and thalamus. Mid-gestational fetal sheep provide a valuable model for studying vulnerability of progenitor oligodendrocytes. Hypoxia followed by asphyxia in newborn piglets replicates the systems injury seen in term newborns. Efficacy of post-insult hypothermia in animal models led to the success of clinical trials in term human neonates. Large animal models are now being used to explore adjunct therapy to augment hypothermic neuroprotection.
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Affiliation(s)
- Raymond C Koehler
- 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Zeng-Jin Yang
- 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer K Lee
- 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA.,2 The Pathobiology Graduate Training Program, Johns Hopkins University, Baltimore, MD, USA
| | - Lee J Martin
- 2 The Pathobiology Graduate Training Program, Johns Hopkins University, Baltimore, MD, USA.,3 Department of Pathology, Division of Neuropathology, Johns Hopkins University, Baltimore, MD, USA
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Lally PJ, Montaldo P, Oliveira V, Soe A, Swamy R, Bassett P, Mendoza J, Atreja G, Kariholu U, Pattnayak S, Sashikumar P, Harizaj H, Mitchell M, Ganesh V, Harigopal S, Dixon J, English P, Clarke P, Muthukumar P, Satodia P, Wayte S, Abernethy LJ, Yajamanyam K, Bainbridge A, Price D, Huertas A, Sharp DJ, Kalra V, Chawla S, Shankaran S, Thayyil S. Magnetic resonance spectroscopy assessment of brain injury after moderate hypothermia in neonatal encephalopathy: a prospective multicentre cohort study. Lancet Neurol 2018; 18:35-45. [PMID: 30447969 PMCID: PMC6291458 DOI: 10.1016/s1474-4422(18)30325-9] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 08/21/2018] [Accepted: 08/26/2018] [Indexed: 12/31/2022]
Abstract
Background In neonatal encephalopathy, the clinical manifestations of injury can only be reliably assessed several years after an intervention, complicating early prognostication and rendering trials of promising neuroprotectants slow and expensive. We aimed to determine the accuracy of thalamic proton magnetic resonance (MR) spectroscopy (MRS) biomarkers as early predictors of the neurodevelopmental abnormalities observed years after neonatal encephalopathy. Methods We did a prospective multicentre cohort study across eight neonatal intensive care units in the UK and USA, recruiting term and near-term neonates who received therapeutic hypothermia for neonatal encephalopathy. We excluded infants with life-threatening congenital malformations, syndromic disorders, neurometabolic diseases, or any alternative diagnoses for encephalopathy that were apparent within 6 h of birth. We obtained T1-weighted, T2-weighted, and diffusion-weighted MRI and thalamic proton MRS 4–14 days after birth. Clinical neurodevelopmental tests were done 18–24 months later. The primary outcome was the association between MR biomarkers and an adverse neurodevelopmental outcome, defined as death or moderate or severe disability, measured using a multivariable prognostic model. We used receiver operating characteristic (ROC) curves to examine the prognostic accuracy of the individual biomarkers. This trial is registered with ClinicalTrials.gov, number NCT01309711. Findings Between Jan 29, 2013, and June 25, 2016, we recruited 223 infants who all underwent MRI and MRS at a median age of 7 days (IQR 5–10), with 190 (85%) followed up for neurological examination at a median age of 23 months (20–25). Of those followed up, 31 (16%) had moderate or severe disability, including one death. Multiple logistic regression analysis could not be done because thalamic N-acetylaspartate (NAA) concentration alone accurately predicted an adverse neurodevelopmental outcome (area under the curve [AUC] of 0·99 [95% CI 0·94–1·00]; sensitivity 100% [74–100]; specificity 97% [90–100]; n=82); the models would not converge when any additional variable was examined. The AUC (95% CI) of clinical examination at 6 h (n=190) and at discharge (n=167) were 0·72 (0·65–0·78) and 0·60 (0·53–0·68), respectively, and the AUC of abnormal amplitude integrated EEG at 6 h (n=169) was 0·73 (0·65–0·79). On conventional MRI (n=190), cortical injury had an AUC of 0·67 (0·60–0·73), basal ganglia or thalamic injury had an AUC of 0·81 (0·75–0·87), and abnormal signal in the posterior limb of internal capsule (PLIC) had an AUC of 0·82 (0·76–0·87). Fractional anisotropy of PLIC (n=65) had an AUC of 0·82 (0·76–0·87). MRS metabolite peak-area ratios (n=160) of NAA–creatine (<1·29) had an AUC of 0·79 (0·72–0·85), of NAA–choline had an AUC of 0·74 (0·66–0·80), and of lactate–NAA (>0·22) had an AUC of 0·94 (0·89–0·97). Interpretation Thalamic proton MRS measures acquired soon after birth in neonatal encephalopathy had the highest accuracy to predict neurdevelopment 2 years later. These methods could be applied to increase the power of neuroprotection trials while reducing their duration. Funding National Institute for Health Research UK.
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Affiliation(s)
- Peter J Lally
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Paolo Montaldo
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Vânia Oliveira
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Aung Soe
- Oliver Fisher Neonatal Unit, Medway NHS Foundation Trust, Kent, UK
| | - Ravi Swamy
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | | | - Josephine Mendoza
- Centre for Perinatal Neuroscience, Imperial College London, London, UK
| | - Gaurav Atreja
- Neonatal Unit, Imperial College Healthcare NHS Trust, London, UK
| | - Ujwal Kariholu
- Neonatal Unit, Imperial College Healthcare NHS Trust, London, UK
| | | | | | - Helen Harizaj
- Oliver Fisher Neonatal Unit, Medway NHS Foundation Trust, Kent, UK
| | - Martin Mitchell
- Oliver Fisher Neonatal Unit, Medway NHS Foundation Trust, Kent, UK
| | | | | | | | | | - Paul Clarke
- Neonatal Unit, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, UK
| | - Priya Muthukumar
- Neonatal Unit, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, UK
| | - Prakash Satodia
- Neonatal Unit, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK
| | - Sarah Wayte
- Neonatal Unit, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK
| | | | - Kiran Yajamanyam
- Neonatal Unit, Liverpool Women's NHS Foundation Trust, Liverpool, UK
| | - Alan Bainbridge
- Neonatal Unit, University College London Hospitals NHS Foundation Trust, London, UK
| | - David Price
- Neonatal Unit, University College London Hospitals NHS Foundation Trust, London, UK
| | - Angela Huertas
- Neonatal Unit, University College London Hospitals NHS Foundation Trust, London, UK
| | - David J Sharp
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, UK
| | - Vaneet Kalra
- Neonatal-Perinatal Medicine, Wayne State University, Detroit, MI, USA
| | - Sanjay Chawla
- Neonatal-Perinatal Medicine, Wayne State University, Detroit, MI, USA
| | - Seetha Shankaran
- Neonatal-Perinatal Medicine, Wayne State University, Detroit, MI, USA
| | - Sudhin Thayyil
- Centre for Perinatal Neuroscience, Imperial College London, London, UK.
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Wassink G, Davidson JO, Lear CA, Juul SE, Northington F, Bennet L, Gunn AJ. A working model for hypothermic neuroprotection. J Physiol 2018; 596:5641-5654. [PMID: 29660115 DOI: 10.1113/jp274928] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/28/2018] [Indexed: 01/04/2023] Open
Abstract
Therapeutic hypothermia significantly improves survival without disability in near-term and full-term newborns with moderate to severe hypoxic-ischaemic encephalopathy. However, hypothermic neuroprotection is incomplete. The challenge now is to find ways to further improve outcomes. One major limitation to progress is that the specific mechanisms of hypothermia are only partly understood. Evidence supports the concept that therapeutic cooling suppresses multiple extracellular death signals, including intracellular pathways of apoptotic and necrotic cell death and inappropriate microglial activation. Thus, the optimal depth of induced hypothermia is that which effectively suppresses the cell death pathways after hypoxia-ischaemia, but without inhibiting recovery of the cellular environment. Thus mild hypothermia needs to be continued until the cell environment has recovered until it can actively support cell survival. This review highlights that key survival cues likely include the inter-related restoration of neuronal activity and growth factor release. This working model suggests that interventions that target overlapping mechanisms, such as anticonvulsants, are unlikely to materially augment hypothermic neuroprotection. We suggest that further improvements are most likely to be achieved with late interventions that maximise restoration of the normal cell environment after therapeutic hypothermia, such as recombinant human erythropoietin or stem cell therapy.
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Affiliation(s)
- Guido Wassink
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Sandra E Juul
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Frances Northington
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - 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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Favié LMA, Cox AR, van den Hoogen A, Nijboer CHA, Peeters-Scholte CMPCD, van Bel F, Egberts TCG, Rademaker CMA, Groenendaal F. Nitric Oxide Synthase Inhibition as a Neuroprotective Strategy Following Hypoxic-Ischemic Encephalopathy: Evidence From Animal Studies. Front Neurol 2018; 9:258. [PMID: 29725319 PMCID: PMC5916957 DOI: 10.3389/fneur.2018.00258] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/03/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Hypoxic-ischemic encephalopathy following perinatal asphyxia is a leading cause of neonatal death and disability worldwide. Treatment with therapeutic hypothermia reduced adverse outcomes from 60 to 45%. Additional strategies are urgently needed to further improve the outcome for these neonates. Inhibition of nitric oxide synthase (NOS) is a potential neuroprotective target. This article reviews the evidence of neuroprotection by nitric oxide (NO) synthesis inhibition in animal models. METHODS Literature search using the EMBASE, Medline, Cochrane, and PubMed databases. Studies comparing NOS inhibition to placebo, with neuroprotective outcome measures, in relevant animal models were included. Methodologic quality of the included studies was assessed. RESULTS 26 studies were included using non-selective or selective NOS inhibition in rat, piglet, sheep, or rabbit animal models. A large variety in outcome measures was reported. Outcome measures were grouped as histological, biological, or neurobehavioral. Both non-selective and selective inhibitors show neuroprotective properties in one or more outcome measures. Methodologic quality was either low or moderate for all studies. CONCLUSION Inhibition of NO synthesis is a promising strategy for additional neuroprotection. In humans, intervention can only take place after the onset of the hypoxic-ischemic event. Therefore, combined inhibition of neuronal and inducible NOS seems the most likely candidate for human clinical trials. Future studies should determine its safety and effectiveness in neonates, as well as a potential sex-specific neuroprotective effect. Researchers should strive to improve methodologic quality of animal intervention studies by using a systematic approach in conducting and reporting of these studies.
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Affiliation(s)
- Laurent M. A. Favié
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands
- Department of Neonatology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, Netherlands
| | - Arlette R. Cox
- Department of Pharmacy, Academic Medical Center, Amsterdam, Netherlands
| | - Agnes van den Hoogen
- Department of Neonatology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, Netherlands
| | - Cora H. A. Nijboer
- Laboratory of NeuroImmunology and Developmental Origins of Disease (NIDOD), University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Frank van Bel
- Department of Neonatology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, Netherlands
- Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Toine C. G. Egberts
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands
- Department of Pharmacoepidemiology and Clinical Pharmacology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Carin M. A. Rademaker
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Floris Groenendaal
- Department of Neonatology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, Netherlands
- Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
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Chen X, Hovanesian V, Naqvi S, Lim YP, Tucker R, Donahue JE, Stopa EG, Stonestreet BS. Systemic infusions of anti-interleukin-1β neutralizing antibodies reduce short-term brain injury after cerebral ischemia in the ovine fetus. Brain Behav Immun 2018; 67:24-35. [PMID: 28780000 PMCID: PMC5696097 DOI: 10.1016/j.bbi.2017.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 07/14/2017] [Accepted: 08/02/2017] [Indexed: 01/27/2023] Open
Abstract
Perinatal hypoxic-ischemic reperfusion (I/R)-related brain injury is a leading cause of neurologic morbidity and life-long disability in children. Infants exposed to I/R brain injury develop long-term cognitive and behavioral deficits, placing a large burden on parents and society. Therapeutic strategies are currently not available for infants with I/R brain damage, except for hypothermia, which can only be used in full term infants with hypoxic-ischemic encephalopathy (HIE). Moreover, hypothermia is only partially protective. Pro-inflammatory cytokines are key contributors to the pathogenesis of perinatal I/R brain injury. Interleukin-1β (IL-1β) is a critical pro-inflammatory cytokine, which has been shown to predict the severity of HIE in infants. We have previously shown that systemic infusions of mouse anti-ovine IL-1β monoclonal antibody (mAb) into fetal sheep resulted in anti-IL-1β mAb penetration into brain, reduced I/R-related increases in IL-1β expression and blood-brain barrier (BBB) dysfunction in fetal brain. The purpose of the current study was to examine the effects of systemic infusions of anti-IL-1β mAb on short-term I/R-related parenchymal brain injury in the fetus by examining: 1) histopathological changes, 2) apoptosis and caspase-3 activity, 3) neuronal degeneration 4) reactive gliosis and 5) myelin basic protein (MBP) immunohistochemical staining. The study groups included non-ischemic controls, placebo-treated ischemic, and anti-IL-1β mAb treated ischemic fetal sheep at 127days of gestation. The systemic intravenous infusions of anti-IL-1β mAb were administered at fifteen minutes and four hours after in utero brain ischemia. The duration of each infusion was two hours. Parenchymal brain injury was evaluated by determining pathological injury scores, ApopTag® positive cells/mm2, caspase-3 activity, Fluoro-Jade B positive cells/mm2, glial fibrillary acidic protein (GFAP) and MBP staining in the brains of fetal sheep 24h after 30min of ischemia. Treatment with anti-IL-1β mAb reduced (P<0.05) the global pathological injury scores, number of apoptotic positive cells/mm2, and caspase-3 activity after ischemia in fetal sheep. The regional pathological scores and Fluoro-Jade B positive cells/mm2 did not differ between the placebo- and anti-IL-1β mAb treated ischemic fetal sheep. The percent of the cortical area stained for GFAP was lower (P<0.05) in the placebo ischemic treated than in the non-ischemic group, but did not differ between the placebo- and anti-IL-1β mAb treated ischemic groups. MBP immunohistochemical expression did not differ among the groups. In conclusion, infusions of anti-IL-1β mAb attenuate short-term I/R-related histopathological tissue injury, apoptosis, and reduce I/R-related increases in caspase-3 activity in ovine fetal brain. Therefore, systemic infusions of anti-IL-1β mAb attenuate short-term I/R-related parenchymal brain injury in the fetus.
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Affiliation(s)
- Xiaodi Chen
- Department of Pediatrics, the Alpert Medical School of Brown University, Women & Infants Hospital of Rhode Island, Providence, RI
| | - Virginia Hovanesian
- Core Research Laboratories, the Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI
| | - Syed Naqvi
- Department of Pediatrics, the Alpert Medical School of Brown University, Women & Infants Hospital of Rhode Island, Providence, RI
| | | | - Richard Tucker
- Department of Pediatrics, the Alpert Medical School of Brown University, Women & Infants Hospital of Rhode Island, Providence, RI
| | - John E. Donahue
- Department of Pathology and Neurosurgery, the Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI
| | - Edward G. Stopa
- Department of Pathology and Neurosurgery, the Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI
| | - Barbara S. Stonestreet
- Department of Pediatrics, the Alpert Medical School of Brown University, Women & Infants Hospital of Rhode Island, Providence, RI
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42
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Effects of therapeutic hypothermia on white matter injury from murine neonatal hypoxia-ischemia. Pediatr Res 2017; 82:518-526. [PMID: 28561815 PMCID: PMC5570671 DOI: 10.1038/pr.2017.75] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/06/2017] [Indexed: 12/20/2022]
Abstract
BackgroundTherapeutic hypothermia (TH) is the standard of care for neonates with hypoxic-ischemic encephalopathy, but it is not fully protective in the clinical setting. Hypoxia-ischemia (HI) may cause white matter injury (WMI), leading to neurological and cognitive dysfunction.MethodsP9 mice were subjected to HI as previously described. Pups underwent 3.5 h of systemic hypothermia or normothermia. Cresyl violet and Perl's iron staining for histopathological scoring of brain sections was completed blindly on all brains. Immunocytochemical (ICC) staining for myelin basic protein (MBP), microglia (Iba1), and astrocytes (glia fibrillary acidic protein (GFAP)) was performed on adjacent sections. Volumetric measurements of MBP coverage were used for quantitative analysis of white matter.ResultsTH provided neuroprotection by injury scoring for the entire group (n=44; P<0.0002). ICC analysis of a subset of brains showed that the lateral caudate was protected from WMI (P<0.05). Analysis revealed decreased GFAP and Iba1 staining in hippocampal regions, mostly CA2/CA3. GFAP and Iba1 directly correlated with injury scores of normothermic brains.ConclusionTH reduced injury, and qualitative data suggest that hippocampus and lateral caudate are protected from HI. Mildly injured brains may better show the benefits of TH. Overall, these data indicate regional differences in WMI susceptibility and inflammation in a P9 murine HI model.
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Galinsky R, Davidson JO, Lear CA, Bennet L, Green CR, Gunn AJ. Connexin hemichannel blockade improves survival of striatal GABA-ergic neurons after global cerebral ischaemia in term-equivalent fetal sheep. Sci Rep 2017; 7:6304. [PMID: 28740229 PMCID: PMC5524909 DOI: 10.1038/s41598-017-06683-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 06/15/2017] [Indexed: 11/17/2022] Open
Abstract
Basal ganglia injury at term remains a major cause of disability, such as cerebral palsy. In this study we tested the hypotheses that blockade of astrocytic connexin hemichannels with a mimetic peptide would improve survival of striatal phenotypic neurons after global cerebral ischaemia in term-equivalent fetal sheep, and that neuronal survival would be associated with electrophysiological recovery. Fetal sheep (0.85 gestation) were randomly assigned to receive a short or long (1 or 25 h) intracerebroventricular infusion of a mimetic peptide or vehicle, starting 90 minutes after 30 minutes of cerebral ischaemia. Sheep were killed 7 days after ischaemia. Cerebral ischaemia was associated with reduced numbers of calbindin-28k, calretinin, parvalbumin and GAD positive striatal neurons (P < 0.05 ischaemia + vehicle, n = 6 vs. sham ischaemia, n = 6) but not ChAT or nNOS positive neurons. Short infusion of peptide (n = 6) did not significantly improve survival of any striatal phenotype. Long infusion of peptide (n = 6) was associated with increased survival of calbindin-28k, calretinin, parvalbumin and GAD positive neurons (P < 0.05 vs. ischaemia + vehicle). Neurophysiological recovery was associated with improved survival of calbindin-28k, calretinin and parvalbumin positive striatal neurons (P < 0.05 for all). In conclusion, connexin hemichannel blockade after cerebral ischaemia in term-equivalent fetal sheep improves survival of striatal GABA-ergic neurons.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, The University of Auckland, Auckland, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Victoria, Australia
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand.
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Millar LJ, Shi L, Hoerder-Suabedissen A, Molnár Z. Neonatal Hypoxia Ischaemia: Mechanisms, Models, and Therapeutic Challenges. Front Cell Neurosci 2017; 11:78. [PMID: 28533743 PMCID: PMC5420571 DOI: 10.3389/fncel.2017.00078] [Citation(s) in RCA: 213] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/07/2017] [Indexed: 12/11/2022] Open
Abstract
Neonatal hypoxia-ischaemia (HI) is the most common cause of death and disability in human neonates, and is often associated with persistent motor, sensory, and cognitive impairment. Improved intensive care technology has increased survival without preventing neurological disorder, increasing morbidity throughout the adult population. Early preventative or neuroprotective interventions have the potential to rescue brain development in neonates, yet only one therapeutic intervention is currently licensed for use in developed countries. Recent investigations of the transient cortical layer known as subplate, especially regarding subplate's secretory role, opens up a novel set of potential molecular modulators of neonatal HI injury. This review examines the biological mechanisms of human neonatal HI, discusses evidence for the relevance of subplate-secreted molecules to this condition, and evaluates available animal models. Neuroserpin, a neuronally released neuroprotective factor, is discussed as a case study for developing new potential pharmacological interventions for use post-ischaemic injury.
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Affiliation(s)
- Lancelot J. Millar
- Molnár Group, Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| | - Lei Shi
- Molnár Group, Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
- JNU-HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of Pharmacy, Jinan UniversityGuangzhou, China
| | | | - Zoltán Molnár
- Molnár Group, Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
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Kim Y, Davidson JO, Green CR, Nicholson LFB, O'Carroll SJ, Zhang J. Connexins and Pannexins in cerebral ischemia. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:224-236. [PMID: 28347700 DOI: 10.1016/j.bbamem.2017.03.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/24/2017] [Accepted: 03/22/2017] [Indexed: 12/12/2022]
Abstract
A common cause of mortality and long-term adult disability, cerebral ischemia or brain ischemia imposes a significant health and financial burden on communities worldwide. Cerebral ischemia is a condition that arises from a sudden loss of blood flow and consequent failure to meet the high metabolic demands of the brain. The lack of blood flow initiates a sequelae of cell death mechanisms, including the activation of the inflammatory pathway, which can ultimately result in irreversible brain tissue damage. In particular, Connexins and Pannexins are non-selective channels with a large pore that have shown to play time-dependent roles in the perpetuation of ischaemic injury. This review highlights the roles of Connexin and Pannexin channels in cell death mechanisms as a promising therapeutic target in cerebral ischemia, and in particular connexin hemichannels which may contribute most of the ATP release as a result of ischemia as well as during reperfusion. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Yeri Kim
- Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland
| | - Joanne O Davidson
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland
| | - Colin R Green
- Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland
| | - Louise F B Nicholson
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland
| | - Simon J O'Carroll
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland
| | - Jie Zhang
- Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland.
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46
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Mehta S, Joshi A, Bajuk B, Badawi N, McIntyre S, Lui K. Eligibility criteria for therapeutic hypothermia: From trials to clinical practice. J Paediatr Child Health 2017; 53:295-300. [PMID: 27701803 DOI: 10.1111/jpc.13378] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 06/17/2016] [Accepted: 07/15/2016] [Indexed: 11/28/2022]
Abstract
AIM Whole body therapeutic hypothermia (TH) for hypoxic ischaemic encephalopathy was introduced into clinical practice in New South Wales (NSW) and Australian Capital Territory in 2007. State-wide policy adopting the eligibility criteria and practice based on trial-designs was published in 2009. METHODS The study was conducted by retrospectively reviewing medical records of all TH infants born between 2007 and 2011 in NSW and Australian Capital Territory to examine if eligibility criteria (assessed against evidence-based policy directives) were met. RESULTS A total of 207 infants received TH, 104 (50%) did not meet the eligibility criteria defined in NSW policy directive. Over the 5-year period, the proportion of infants meeting the eligibility criteria did not change. Seventy percent of infants (73 out of 104) not meeting eligibility criteria did not fulfil the criteria for 'evidence of asphyxia', although half of them met 'moderate or severe encephalopathy criterion'. Adverse events (hypotension, coagulopathy and arrhythmia), were more common in the 'criteria met' group than the 'criteria not met' group (89 vs. 71%, P = 0.001). Similar proportions of infants had TH discontinued before 72 h (criteria met: 32 (31%) vs. criteria not met: 27(26%)). Most frequent reason for early cessation was 'palliation' (19/32, 59%) in criteria met and 'clinical improvement' (16/27, 59%) in criteria not met group. CONCLUSIONS Many TH infants were treated based on clinician judgement, though not meeting the trial-design policy criteria. Early TH cessation (<72 h) was common. Future studies are warranted on long-term neurodevelopmental outcomes for all infants receiving TH particularly those with early cessation of therapy.
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Affiliation(s)
- Shailender Mehta
- School of Women's and Children's Health, University of New South Wales, Sydney, New South Wales, Australia.,Department of Neonatology, Fiona Stanley Hospital, Perth, Western Australia, Australia.,School of Medicine, University of Notre Dame, Fremantle, Western Australia, Australia
| | - Anjali Joshi
- School of Women's and Children's Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Barbara Bajuk
- NSW Pregnancy and Newborn Services Network, Sydney, New South Wales, Australia.,School of Public Health, University of Sydney, Sydney, New South Wales, Australia
| | - Nadia Badawi
- Department of Neonatology, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,School of Medicine, University of Sydney, Sydney, New South Wales, Australia.,School of Medicine, University of Notre Dame, Sydney, New South Wales, Australia
| | - Sarah McIntyre
- Cerebral Palsy Alliance, University of Notre Dame, Sydney, New South Wales, Australia
| | - Kei Lui
- School of Women's and Children's Health, University of New South Wales, Sydney, New South Wales, Australia.,Department of Newborn Care, Royal Hospital for Women, Sydney, New South Wales, Australia
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Patra A, Chen X, Sadowska GB, Zhang J, Lim YP, Padbury JF, Banks WA, Stonestreet BS. Neutralizing anti-interleukin-1β antibodies reduce ischemia-related interleukin-1β transport across the blood-brain barrier in fetal sheep. Neuroscience 2017; 346:113-125. [PMID: 28089577 DOI: 10.1016/j.neuroscience.2016.12.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/25/2016] [Accepted: 12/29/2016] [Indexed: 10/20/2022]
Abstract
Hypoxic ischemic insults predispose to perinatal brain injury. Pro-inflammatory cytokines are important in the evolution of this injury. Interleukin-1β (IL-1β) is a key mediator of inflammatory responses and elevated IL-1β levels in brain correlate with adverse neurodevelopmental outcomes after brain injury. Impaired blood-brain barrier (BBB) function represents an important component of hypoxic-ischemic brain injury in the fetus. In addition, ischemia-reperfusion increases cytokine transport across the BBB of the ovine fetus. Reducing pro-inflammatory cytokine entry into brain could represent a novel approach to attenuate ischemia-related brain injury. We hypothesized that infusions of neutralizing IL-1β monoclonal antibody (mAb) reduce IL-1β transport across the BBB after ischemia in the fetus. Fetal sheep were studied 24-h after 30-min of carotid artery occlusion. Fetuses were treated with placebo- or anti-IL-1β mAb intravenously 15-min and 4-h after ischemia. Ovine IL-1β protein expressed from IL-1β pGEX-2T vectors in Escherichia coli (E. coli) BL-21 cells was produced, purified, and radiolabeled with 125I. BBB permeability was quantified using the blood-to-brain transfer constant (Ki) with 125I-radiolabeled-IL-1β. Increases in anti-IL-1β mAb were observed in the brain of the mAb-treated group (P<0.001). Blood-to-brain transport of 125I-IL-1β was lower (P<0.04) across brain regions in the anti-IL-1β mAb-treated than placebo-treated ischemic fetuses. Plasma 125I-IL-1β counts were higher (P<0.001) in the anti-IL-1β mAb- than placebo-treated ischemic fetuses. Systemic infusions of anti-IL-1β mAb reduce IL-1β transport across the BBB after ischemia in the ovine fetus. Our findings suggest that conditions associated with increases in systemic pro-inflammatory cytokines and neurodevelopmental impairment could benefit from an anti-cytokine therapeutic strategy.
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Affiliation(s)
- Aparna Patra
- Pediatrics, Women & Infants Hospital of Rhode Island, The Alpert Medical School of Brown University, Providence, RI 02905, United States.
| | - Xiaodi Chen
- Pediatrics, Women & Infants Hospital of Rhode Island, The Alpert Medical School of Brown University, Providence, RI 02905, United States
| | - Grazyna B Sadowska
- Pediatrics, Women & Infants Hospital of Rhode Island, The Alpert Medical School of Brown University, Providence, RI 02905, United States
| | - Jiyong Zhang
- Pediatrics, Women & Infants Hospital of Rhode Island, The Alpert Medical School of Brown University, Providence, RI 02905, United States
| | - Yow-Pin Lim
- ProThera Biologics, Providence, RI 02903, United States
| | - James F Padbury
- Pediatrics, Women & Infants Hospital of Rhode Island, The Alpert Medical School of Brown University, Providence, RI 02905, United States
| | - William A Banks
- Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, WA 98104, United States
| | - Barbara S Stonestreet
- Pediatrics, Women & Infants Hospital of Rhode Island, The Alpert Medical School of Brown University, Providence, RI 02905, United States.
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48
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Perentos N, Nicol AU, Martins AQ, Stewart JE, Taylor P, Morton AJ. Techniques for chronic monitoring of brain activity in freely moving sheep using wireless EEG recording. J Neurosci Methods 2016; 279:87-100. [PMID: 27914975 DOI: 10.1016/j.jneumeth.2016.11.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/21/2016] [Accepted: 11/24/2016] [Indexed: 12/18/2022]
Abstract
BACKGROUND Large mammals with complex central nervous systems offer new possibilities for translational research into basic brain function. Techniques for monitoring brain activity in large mammals, however, are not as well developed as they are in rodents. NEW METHOD We have developed a method for chronic monitoring of electroencephalographic (EEG) activity in unrestrained sheep. We describe the methods for behavioural training prior to implantation, surgical procedures for implantation, a protocol for reliable anaesthesia and recovery, methods for EEG data collection, as well as data pertaining to suitability and longevity of different types of electrodes. RESULTS Sheep tolerated all procedures well, and surgical complications were minimal. Electrode types used included epidural and subdural screws, intracortical needles and subdural disk electrodes, with the latter producing the best and most reliable results. The implants yielded longitudinal EEG data of consistent quality for periods of at least a year, and in some cases up to 2 years. COMPARISON WITH EXISTING METHODS This is the first detailed methodology to be described for chronic brain function monitoring in freely moving unrestrained sheep. CONCLUSIONS The developed method will be particularly useful in chronic investigations of brain activity during normal behaviour that can include sleep, learning and memory. As well, within the context of disease, the method can be used to monitor brain pathology or the progress of therapeutic trials in transgenic or natural disease models in sheep.
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Affiliation(s)
- N Perentos
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - A U Nicol
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - A Q Martins
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - J E Stewart
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - P Taylor
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - A J Morton
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom.
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49
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Keunen H, Deutz NEP, Van Reempts JLH, Hasaart THM. Transient Umbilical Cord Occlusion in Late-Gestation Fetal Sheep Results in Hippocampal Damage but Not in Cerebral Arteriovenous Difference for Nitrite, a Stable End Product of Nitric Oxide. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/107155769900600302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | | | - Jos L. H. Van Reempts
- Departments of Obstetrics and Gynecology, and Surgery, University Hospital Maastricht, Maastricht, The Netherlands, and Department of Life Sciences, Janssen Research Foundation, Beerse, Belgium
| | - Tom H. M. Hasaart
- Departments of Obstetrics and Gynecology, and Surgery, University Hospital Maastricht, Maastricht, The Netherlands, and Department of Life Sciences, Janssen Research Foundation, Beerse, Belgium
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50
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Duncan JR, Camm E, Loeliger M, Cock ML, Harding R, Rees SM. Effects of Umbilical Cord Occlusion in Late Gestation on the Ovine Fetal Brain and Retina. ACTA ACUST UNITED AC 2016; 11:369-76. [PMID: 15350249 DOI: 10.1016/j.jsgi.2004.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Previous studies on the effects of umbilical cord occlusion (UCO) on the fetal brain have focused on short-term alterations, and in most cases have used only subjective techniques to evaluate brain injury. Our aim was to assess quantitatively the persistent consequences of UCO on the developing brain; we also examined the retina. METHODS We subjected fetal sheep to a single episode of UCO at 126 days of gestation (term approximately 147 days) to induce at least 10 minutes of isoelectric fetal electrocorticogram (ECoG). RESULTS UCO resulted in fetal asphyxia and transient mild alterations in fetal mean arterial pressure (MAP). UCO did not result in significant injury to the developing brain or retina when assessed 15 days after the insult. There was no change in the endogenous expression of brain-derived neurotrophic factor (BDNF) protein in the hippocampus, nor was there a significant loss of CA1 hippocampal pyramidal cells. However, this insult did result in subtle neuropathologic alterations in the brain, including a reduction in the weight of the cerebral hemispheres, an increase in the areal density of cerebellar Purkinje cells, and enlarged perivascular spaces around blood vessels and inflammatory cells in the cerebral white matter. UCO did not affect the thickness of the central or peripheral retina or the numbers of retinal dopaminergic, cholinergic, and nitrergic amacrine cells. CONCLUSIONS Thus, while 10 minutes of UCO did not result in overt injury to the fetal brain or retina, the observed changes in the fetal brain suggest altered growth of neural processes, which may contribute to neurologic deficits postnatally or to increased vulnerability of the brain to later insults during either the remainder of gestation or after birth.
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Affiliation(s)
- Jhodie R Duncan
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Australia.
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