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Janowska J, Gargas J, Zajdel K, Wieteska M, Lipinski K, Ziemka-Nalecz M, Frontczak-Baniewicz M, Sypecka J. Oligodendrocyte progenitor cells' fate after neonatal asphyxia-Puzzling implications for the development of hypoxic-ischemic encephalopathy. Brain Pathol 2024:e13255. [PMID: 38504469 DOI: 10.1111/bpa.13255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 03/01/2024] [Indexed: 03/21/2024] Open
Abstract
Premature birth or complications during labor can cause temporary disruption of cerebral blood flow, often followed by long-term disturbances in brain development called hypoxic-ischemic (HI) encephalopathy. Diffuse damage to the white matter is the most frequently detected pathology in this condition. We hypothesized that oligodendrocyte progenitor cell (OPC) differentiation disturbed by mild neonatal asphyxia may affect the viability, maturation, and physiological functioning of oligodendrocytes. To address this issue, we studied the effect of temporal HI in the in vivo model in P7 rats with magnetic resonance imaging (MRI), microscopy techniques and biochemical analyses. Moreover, we recreated the injury in vitro performing the procedure of oxygen-glucose deprivation on rat neonatal OPCs to determine its effect on cell viability, proliferation, and differentiation. In the in vivo model, MRI evaluation revealed changes in the volume of different brain regions, as well as changes in the directional diffusivity of water in brain tissue that may suggest pathological changes to myelinated neuronal fibers. Hypomyelination was observed in the cortex, striatum, and CA3 region of the hippocampus. Severe changes to myelin ultrastructure were observed, including delamination of myelin sheets. Interestingly, shortly after the injury, an increase in oligodendrocyte proliferation was observed, followed by an overproduction of myelin proteins 4 weeks after HI. Results verified with the in vitro model indicate, that in the first days after damage, OPCs do not show reduced viability, intensively proliferate, and overexpress myelin proteins and oligodendrocyte-specific transcription factors. In conclusion, despite the increase in oligodendrocyte proliferation and myelin protein expression after HI, the production of functional myelin sheaths in brain tissue is impaired. Presented study provides a detailed description of oligodendrocyte pathophysiology developed in an effect of HI injury, resulting in an altered CNS myelination. The described models may serve as useful tools for searching and testing effective of effective myelination-supporting therapies for HI injuries.
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Affiliation(s)
- Justyna Janowska
- Department of NeuroRepair, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | - Justyna Gargas
- Department of NeuroRepair, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | - Karolina Zajdel
- NOMATEN Center of Excellence, National Center for Nuclear Research, Otwock, Poland
- Electron Microscopy Research Unit, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | - Michal Wieteska
- Small Animal Magnetic Resonance Imaging Laboratory, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | - Kamil Lipinski
- Division of Nuclear and Medical Electronics, Warsaw University of Technology, Warsaw, Poland
| | | | | | - Joanna Sypecka
- Department of NeuroRepair, Mossakowski Medical Research Institute PAS, Warsaw, Poland
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Romantsik O, Moreira A, Thébaud B, Ådén U, Ley D, Bruschettini M. Stem cell-based interventions for the prevention and treatment of intraventricular haemorrhage and encephalopathy of prematurity in preterm infants. Cochrane Database Syst Rev 2023; 2:CD013201. [PMID: 36790019 PMCID: PMC9932000 DOI: 10.1002/14651858.cd013201.pub3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
BACKGROUND Germinal matrix-intraventricular haemorrhage (GMH-IVH) and encephalopathy of prematurity (EoP) remain substantial issues in neonatal intensive care units worldwide. Current therapies to prevent or treat these conditions are limited. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal studies. This is an update of the 2019 review, which did not include EoP. OBJECTIVES To evaluate the benefits and harms of stem cell-based interventions for prevention or treatment of GM-IVH and EoP in preterm infants. SEARCH METHODS We used standard, extensive Cochrane search methods. The latest search was April 2022. SELECTION CRITERIA We attempted to include randomised controlled trials, quasi-randomised controlled trials, and cluster trials comparing 1. stem cell-based interventions versus control; 2. mesenchymal stromal cells (MSCs) of type or source versus MSCs of other type or source; 3. stem cell-based interventions other than MSCs of type or source versus stem cell-based interventions other than MSCs of other type or source; or 4. MSCs versus stem cell-based interventions other than MSCs. For prevention studies, we included extremely preterm infants (less than 28 weeks' gestation), 24 hours of age or less, without ultrasound diagnosis of GM-IVH or EoP; for treatment studies, we included preterm infants (less than 37 weeks' gestation), of any postnatal age, with ultrasound diagnosis of GM-IVH or with EoP. DATA COLLECTION AND ANALYSIS We used standard Cochrane methods. Our primary outcomes were 1. all-cause neonatal mortality, 2. major neurodevelopmental disability, 3. GM-IVH, 4. EoP, and 5. extension of pre-existing non-severe GM-IVH or EoP. We planned to use GRADE to assess certainty of evidence for each outcome. MAIN RESULTS We identified no studies that met our inclusion criteria. Three studies are currently registered and ongoing. Phase 1 trials are described in the 'Excluded studies' section. AUTHORS' CONCLUSIONS No evidence is currently available to evaluate the benefits and harms of stem cell-based interventions for treatment or prevention of GM-IVH or EoP in preterm infants. We identified three ongoing studies, with a sample size range from 20 to 200. In two studies, autologous cord blood mononuclear cells will be administered to extremely preterm infants via the intravenous route; in one, intracerebroventricular injection of MSCs will be administered to preterm infants up to 34 weeks' gestational age.
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Affiliation(s)
- Olga Romantsik
- Department of Clinical Sciences Lund, Paediatrics, Lund University, Skåne University Hospital, Lund, Sweden
| | - Alvaro Moreira
- Pediatrics, Division of Neonatology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Bernard Thébaud
- Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Canada
- Ottawa Hospital Research Institute, Sprott Centre for Stem Cell Research, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Ulrika Ådén
- Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - David Ley
- Department of Clinical Sciences Lund, Paediatrics, Lund University, Skåne University Hospital, Lund, Sweden
| | - Matteo Bruschettini
- Department of Clinical Sciences Lund, Paediatrics, Lund University, Skåne University Hospital, Lund, Sweden
- Cochrane Sweden, Lund University, Skåne University Hospital, Lund, Sweden
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Xavier N, Mubina J, Marie-Ange D, Nicolas VD, Dorothée DS, Catherine FB. Impact of Congenital Heart Defects on the Developing Brain. Pediatr Dev Pathol 2022; 25:419-434. [PMID: 35285332 DOI: 10.1177/10935266211045365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Congenital heart defects (CHD) are responsible for neurodevelopmental delays that were initially attributed to brain injury resulting from cardiac surgery. However, prenatal imaging have shown that brain anomalies are present at birth. The aim of this study was to assess in utero brain injuries before birth in fetuses/neonates with congenital cardiopathies. METHODS A complete autopsy evaluation with detailed study of the cardiopathy and neuropathological study was performed in 40 fetuses/neonates. Syndromic congenital cardiopathies were excluded because of the potential other causes of brain injury. The patients were classified into two groups according to their term at death. RESULTS Statistical analyses indicated the mean brain weight was not significantly different between subjects with different morphological types of congenital cardiopathies. However, the brain weight was at or below the fifth percentile in most third-trimester subjects compared to normal brain weight in second-trimester subjects. Low brain weight in third-trimester subjects was also associated with frequent lesions similar to those described in preterm infants, with a particular involvement of white matter and its components. CONCLUSIONS These observations allowed us to establish the timing and impact of prenatal neuropathological lesions on brain development, and to correlate them with imaging data reported in the literature.
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Affiliation(s)
- Navarri Xavier
- Research Center, Sainte-Justine Hospital, Montreal, Quebec, Canada
| | - Jovanovic Mubina
- Department of Pathology, Sainte-Justine Hospital, Montreal, Quebec, Canada
| | - Delrue Marie-Ange
- Department of Genetics, Sainte-Justine Hospital, Montreal, Quebec, Canada
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4
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Xiong Y, Wintermark P. The Role of Sildenafil in Treating Brain Injuries in Adults and Neonates. Front Cell Neurosci 2022; 16:879649. [PMID: 35620219 PMCID: PMC9127063 DOI: 10.3389/fncel.2022.879649] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/04/2022] [Indexed: 12/02/2022] Open
Abstract
Sildenafil is a recognized treatment for patients suffering from erectile dysfunction and pulmonary hypertension. However, new evidence suggests that it may have a neuroprotective and a neurorestorative role in the central nervous system of both adults and neonates. Phosphodiesterase type 5-the target of sildenafil-is distributed in many cells throughout the body, including neurons and glial cells. This study is a comprehensive review of the demonstrated effects of sildenafil on the brain with respect to its function, extent of injury, neurons, neuroinflammation, myelination, and cerebral vessels.
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Affiliation(s)
- Ying Xiong
- Department of Anesthesiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Pia Wintermark
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Division of Newborn Medicine, Department of Pediatrics, Montreal Children’s Hospital, Montreal, QC, Canada
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Ma X, Shi Y. Whether erythropoietin can be a neuroprotective agent against premature brain injury: cellular mechanisms and clinical efficacy. Curr Neuropharmacol 2021; 20:611-629. [PMID: 34030616 DOI: 10.2174/1570159x19666210524154519] [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: 01/23/2021] [Revised: 04/27/2021] [Accepted: 05/08/2021] [Indexed: 11/22/2022] Open
Abstract
Preterm infants are at high risk of brain injury. With more understanding of the preterm brain injury's pathogenesis, neuroscientists are looking for more effective methods to prevent and treat it, among which erythropoietin (Epo) is considered as a prime candidate. This review tries to clarify the possible mechanisms of Epo in preterm neuroprotection and summarize updated evidence considering Epo as a pharmacological neuroprotective strategy in animal models and clinical trials. To date, various animal models have validated that Epo is an anti-apoptotic, anti-inflammatory, anti-oxidant, anti-excitotoxic, neurogenetic, erythropoietic, angiogenetic, and neurotrophic agent, thus preventing preterm brain injury. However, although the scientific rationale and preclinical data for Epo's neuroprotective effect are promising, when translated to bedside, the results vary in different studies, especially in its long-term efficacy. Based on existing evidence, it is still too early to recommend Epo as the standard treatment for preterm brain injury.
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Affiliation(s)
- Xueling Ma
- Department of Neonatology, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing 400014, China
| | - Yuan Shi
- Department of Neonatology, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing 400014, China
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6
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Schumacher M, Liere P, Ghoumari A. Progesterone and fetal-neonatal neuroprotection. Best Pract Res Clin Obstet Gynaecol 2020; 69:50-61. [PMID: 33039311 DOI: 10.1016/j.bpobgyn.2020.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 09/01/2020] [Indexed: 02/05/2023]
Abstract
The role of progesterone goes beyond the maintenance of pregnancy. The hormone, indeed, protects the developing fetal brain and influences its maturation. Metabolomes analyzed by mass spectrometric methods have revealed the great diversity of steroids in maternal plasma and fetal fluids, but their developmental significance remains to be investigated. Progesterone and its metabolites reach highest levels during the third trimester, when the brain growth spurt occurs: its volume triples, synaptogenesis is particularly active, and axons start to be myelinated. This developmental stage coincides with a period of great vulnerability. Studies in sheep have shown that progesterone and its metabolite allopregnanolone protect the vulnerable fetal brain. Work in rats and mice have demonstrated that progesterone plays an important role in myelin formation. These experimental studies are discussed in relation to preterm birth. Influences of progesterone on very early stages of neural development at the beginning of pregnancy are yet to be explored.
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Affiliation(s)
- Michael Schumacher
- U1195 "Diseases and Hormones of the Nervous System", Inserm and University Paris-Saclay, 80, Rue Du Général Leclerc, 94276, Kremlin-Bicêtre, France.
| | - Philippe Liere
- U1195 "Diseases and Hormones of the Nervous System", Inserm and University Paris-Saclay, 80, Rue Du Général Leclerc, 94276, Kremlin-Bicêtre, France
| | - Abdelmoumen Ghoumari
- U1195 "Diseases and Hormones of the Nervous System", Inserm and University Paris-Saclay, 80, Rue Du Général Leclerc, 94276, Kremlin-Bicêtre, France
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7
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Agut T, Alarcon A, Cabañas F, Bartocci M, Martinez-Biarge M, Horsch S. Preterm white matter injury: ultrasound diagnosis and classification. Pediatr Res 2020; 87:37-49. [PMID: 32218534 PMCID: PMC7098888 DOI: 10.1038/s41390-020-0781-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
White matter injury (WMI) is the most frequent form of preterm brain injury. Cranial ultrasound (CUS) remains the preferred modality for initial and sequential neuroimaging in preterm infants, and is reliable for the diagnosis of cystic periventricular leukomalacia. Although magnetic resonance imaging is superior to CUS in detecting the diffuse and more subtle forms of WMI that prevail in very premature infants surviving nowadays, recent improvement in the quality of neonatal CUS imaging has broadened the spectrum of preterm white matter abnormalities that can be detected with this technique. We propose a structured CUS assessment of WMI of prematurity that seeks to account for both cystic and non-cystic changes, as well as signs of white matter loss and impaired brain growth and maturation, at or near term equivalent age. This novel assessment system aims to improve disease description in both routine clinical practice and clinical research. Whether this systematic assessment will improve prediction of outcome in preterm infants with WMI still needs to be evaluated in prospective studies.
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Affiliation(s)
- Thais Agut
- Department of Neonatology, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain.
| | - Ana Alarcon
- 0000 0001 0663 8628grid.411160.3Department of Neonatology, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Fernando Cabañas
- 0000 0000 8970 9163grid.81821.32Department of Neonatology, Quironsalud Madrid University Hospital and Biomedical Research Foundation, La Paz University Hospital Madrid, Madrid, Spain
| | - Marco Bartocci
- Department of Women’s and Children’s Health, Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden
| | - Miriam Martinez-Biarge
- 0000 0001 2113 8111grid.7445.2Department of Paediatrics, Imperial College London, London, UK
| | - Sandra Horsch
- 0000 0000 8778 9382grid.491869.bDepartment of Neonatology, Helios Klinikum Berlin Buch, Berlin, Germany ,0000 0004 1937 0626grid.4714.6Department Clinical Science Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden
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8
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Axonal degeneration in an in vitro model of ischemic white matter injury. Neurobiol Dis 2019; 134:104672. [PMID: 31707117 DOI: 10.1016/j.nbd.2019.104672] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/18/2019] [Accepted: 11/06/2019] [Indexed: 01/15/2023] Open
Abstract
Ischemic white matter injuries underlie cognitive decline in the elderly and vascular dementia. Ischemia in the subcortical white matter is caused by chronic reduction of blood flow due to narrowing of small arterioles. However, it remains unclear how chronic ischemia leads to white matter pathology. We aimed to develop an in vitro model of ischemic white matter injury using organotypic slice cultures. Cultured cerebellar slices preserved fully myelinated white matter tracts that were amenable to chronic hypoxic insult. Prolonged hypoxia caused progressive morphological evidence of axonal degeneration with focal constrictions and swellings. In contrast, myelin sheaths and oligodendrocytes exhibited remarkable resilience to hypoxia. The cytoskeletal degradation of axons was accompanied by mitochondrial shortening and lysosomal activation. Multiple pharmacological manipulations revealed that the AMPA glutamate receptor, calpain proteolysis, and lysosomal proteases were independently implicated in hypoxia-induced axonal degeneration in our model. Thus, our in vitro model would be a novel experimental system to explore molecular mechanisms of ischemic white matter injury. Furthermore, we verified that the in vitro assay could be successfully utilized to screen for molecules that can ameliorate hypoxia/ischemia-induced axonal degeneration.
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9
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Ceprián M, Vargas C, García-Toscano L, Penna F, Jiménez-Sánchez L, Achicallende S, Elezgarai I, Grandes P, Hind W, Pazos MR, Martínez-Orgado J. Cannabidiol Administration Prevents Hypoxia-Ischemia-Induced Hypomyelination in Newborn Rats. Front Pharmacol 2019; 10:1131. [PMID: 31611802 PMCID: PMC6775595 DOI: 10.3389/fphar.2019.01131] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/30/2019] [Indexed: 01/09/2023] Open
Abstract
Neonatal hypoxia-ischemia (HI) is a risk factor for myelination disturbances, a key factor for cerebral palsy. Cannabidiol (CBD) protects neurons and glial cells after HI insult in newborn animals. We hereby aimed to study CBD’s effects on long-lasting HI-induced myelination deficits in newborn rats. Thus, P7 Wistar rats received s.c. vehicle (HV) or cannabidiol (HC) after HI brain damage (left carotid artery electrocoagulation plus 10% O2 for 112 min). Controls were non-HI pups. At P37, neurobehavioral tests were performed and immunohistochemistry [quantifying mature oligodendrocyte (mOL) populations and myelin basic protein (MBP) density] and electron microscopy (determining axon number, size, and myelin thickness) studies were conducted in cortex (CX) and white matter (WM). Expression of brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) were analyzed by western blot at P14. HI reduced mOL or MBP in CX but not in WM. In both CX and WM, axon density and myelin thickness were reduced. MBP impairment correlated with functional deficits. CBD administration resulted in normal function associated with normal mOL and MBP, as well as normal axon density and myelin thickness in all areas. CBD’s effects were not associated with increased BDNF or GDNF expression. In conclusion, HI injury in newborn rats resulted in long-lasting myelination disturbance, associated with functional impairment. CBD treatment preserved function and myelination, likely as a part of a general neuroprotective effect.
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Affiliation(s)
- María Ceprián
- Department of Experimental Medicine, Health Research Institute Puerta de Hierro Majadahonda, Madrid, Spain.,Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense, Madrid, Spain
| | - Carlos Vargas
- Division of Neonatology, Hospital Clínico San Carlos - IdISSC, Madrid, Spain
| | - Laura García-Toscano
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense, Madrid, Spain.,CIBER de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Federica Penna
- Department of DBSV, Laboratory of Neuropsychopharmacology, University of Insubria, Varese, Italy
| | - Laura Jiménez-Sánchez
- Department of Experimental Medicine, Health Research Institute Puerta de Hierro Majadahonda, Madrid, Spain
| | - Svein Achicallende
- School of Medicine and Nursery, Universidad del País Vasco, Bilbao, Spain
| | - Izaskun Elezgarai
- School of Medicine and Nursery, Universidad del País Vasco, Bilbao, Spain
| | - Pedro Grandes
- School of Medicine and Nursery, Universidad del País Vasco, Bilbao, Spain
| | | | - M Ruth Pazos
- Department of Experimental Medicine, Health Research Institute Puerta de Hierro Majadahonda, Madrid, Spain.,Laboratorio de Apoyo a la Investigación, Hospital Universitario Fundación Alcorcón, Madrid, Spain
| | - José Martínez-Orgado
- Department of Experimental Medicine, Health Research Institute Puerta de Hierro Majadahonda, Madrid, Spain.,Division of Neonatology, Hospital Clínico San Carlos - IdISSC, Madrid, Spain
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10
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Volpe JJ. Dysmaturation of Premature Brain: Importance, Cellular Mechanisms, and Potential Interventions. Pediatr Neurol 2019; 95:42-66. [PMID: 30975474 DOI: 10.1016/j.pediatrneurol.2019.02.016] [Citation(s) in RCA: 167] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/12/2019] [Accepted: 02/19/2019] [Indexed: 02/07/2023]
Abstract
Prematurity, especially preterm birth (less than 32 weeks' gestation), is common and associated with high rates of both survival and neurodevelopmental disability, especially apparent in cognitive spheres. The neuropathological substrate of this disability is now recognized to be related to a variety of dysmaturational disturbances of the brain. These disturbances follow initial brain injury, particularly cerebral white matter injury, and involve many of the extraordinary array of developmental events active in cerebral white and gray matter structures during the premature period. This review delineates these developmental events and the dysmaturational disturbances that occur in premature infants. The cellular mechanisms involved in the genesis of the dysmaturation are emphasized, with particular focus on the preoligodendrocyte. A central role for the diffusely distributed activated microglia and reactive astrocytes in the dysmaturation is now apparent. As these dysmaturational cellular mechanisms appear to occur over a relatively long time window, interventions to prevent or ameliorate the dysmaturation, that is, neurorestorative interventions, seem possible. Such interventions include pharmacologic agents, especially erythropoietin, and particular attention has also been paid to such nutritional factors as quality and source of milk, breastfeeding, polyunsaturated fatty acids, iron, and zinc. Recent studies also suggest a potent role for interventions directed at various experiential factors in the neonatal period and infancy, i.e., provision of optimal auditory and visual exposures, minimization of pain and stress, and a variety of other means of environmental behavioral enrichment, in enhancing brain development.
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Affiliation(s)
- Joseph J Volpe
- Department of Neurology, Harvard Medical School, Boston, Massachusetts; Department of Pediatric Newborn Medicine, Harvard Medical School, Boston, Massachusetts.
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11
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Abstract
Despite the advances in neonatal intensive care, the preterm brain remains vulnerable to white matter injury (WMI) and disruption of normal brain development (i.e., dysmaturation). Compared to severe cystic WMI encountered in the past decades, contemporary cohorts of preterm neonates experience milder WMIs. More than destructive lesions, disruption of the normal developmental trajectory of cellular elements of the white and the gray matter occurs. In the acute phase, in response to hypoxia-ischemia and/or infection and inflammation, multifocal areas of necrosis within the periventricular white matter involve all cellular elements. Later, chronic WMI is characterized by diffuse WMI with aberrant regeneration of oligodendrocytes, which fail to mature to myelinating oligodendrocytes, leading to myelination disturbances. Complete neuronal degeneration classically accompanies necrotic white matter lesions, while altered neurogenesis, represented by a reduction of the dendritic arbor and synapse formation, is observed in response to diffuse WMI. Neuroimaging studies now provide more insight in assessing both injury and dysmaturation of both gray and white matter. Preterm brain injury remains an important cause of neurodevelopmental disabilities, which are still observed in up to 50% of the preterm survivors and take the form of a complex combination of motor, cognitive, and behavioral concerns.
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Affiliation(s)
- Juliane Schneider
- Department of Woman-Mother-Child, Clinic of Neonatology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Steven P Miller
- Division of Neurology and Centre for Brain and Mental Health, Hospital for Sick Children, Toronto, ON, Canada.
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12
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Yuan F, Chang S, Luo L, Li Y, Wang L, Song Y, Qu M, Zhang Z, Yang GY, Wang Y. cxcl12 gene engineered endothelial progenitor cells further improve the functions of oligodendrocyte precursor cells. Exp Cell Res 2018; 367:222-231. [PMID: 29614310 DOI: 10.1016/j.yexcr.2018.03.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/28/2018] [Accepted: 03/30/2018] [Indexed: 11/18/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) are needed for white matter repair after various brain injury. Means that promote OPC functions could benefit white matter recovery after injury. Chemokine CXCL12 and endothelial progenitor cells (EPCs) both have been shown to promote remyelination. We hypothesize that the beneficial effects of EPCs and CXCL12 can be harnessed by genetically modifying EPCs with cxcl12 to synergistically improve the functions of OPCs. In this work, CXCL12-EPC was generated using virus-mediated gene transfer. OPCs were cultured with CXCL12-EPC conditioned media (CM) to analyze its impact on the proliferation, migration, differentiation and survival properties of OPCs. We blocked or knocked-down the receptors of CXCL12, namely CXCR4 and CXCR7, respectively to investigate their functions in regulating OPCs properties. Results revealed that CXCL12-EPC CM further promoted OPCs behavioral properties and upregulated the expression of PDGFR-α, bFGF, CXCR4 and CXCR7 in OPCs, albeit following different time course. Blocking CXCR4 diminished the beneficial effects of CXCL12 on OPCs proliferation and migration, while knocking down CXCR7 inhibited OPCs differentiation. Our results supported that cxcl12 gene modification of EPCs further promoted EPCs' ability in augmenting the remyelination properties of OPCs, suggesting that CXCL12-EPC hold great potential in white matter repair.
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Affiliation(s)
- Fang Yuan
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Shuang Chang
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Longlong Luo
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Yaning Li
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Liping Wang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Yaying Song
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Meijie Qu
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Zhijun Zhang
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Guo-Yuan Yang
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China; Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Yongting Wang
- Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200030, China.
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Doyle S, Hansen DB, Vella J, Bond P, Harper G, Zammit C, Valentino M, Fern R. Vesicular glutamate release from central axons contributes to myelin damage. Nat Commun 2018. [PMID: 29531223 PMCID: PMC5847599 DOI: 10.1038/s41467-018-03427-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The axon myelin sheath is prone to injury associated with N-methyl-d-aspartate (NMDA)-type glutamate receptor activation but the source of glutamate in this context is unknown. Myelin damage results in permanent action potential loss and severe functional deficit in the white matter of the CNS, for example in ischemic stroke. Here, we show that in rats and mice, ischemic conditions trigger activation of myelinic NMDA receptors incorporating GluN2C/D subunits following release of axonal vesicular glutamate into the peri-axonal space under the myelin sheath. Glial sources of glutamate such as reverse transport did not contribute significantly to this phenomenon. We demonstrate selective myelin uptake and retention of a GluN2C/D NMDA receptor negative allosteric modulator that shields myelin from ischemic injury. The findings potentially support a rational approach toward a low-impact prophylactic therapy to protect patients at risk of stroke and other forms of excitotoxic injury. Neuronal activity can lead to vesicular release of glutamate. Here the authors demonstrate that vesicular release of glutamate occurs in axons during ischemic conditions, and that an allosteric modulator of GluN2C/D is protective in models of ischemic injury.
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Affiliation(s)
- Sean Doyle
- University of Plymouth, Plymouth, PL6 8BY, UK
| | | | | | - Peter Bond
- University of Plymouth, Plymouth, PL6 8BY, UK
| | | | | | | | - Robert Fern
- University of Plymouth, Plymouth, PL6 8BY, UK.
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14
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Jackson J, Bianco G, Rosa AO, Cowan K, Bond P, Anichtchik O, Fern R. White matter tauopathy: Transient functional loss and novel myelin remodeling. Glia 2018; 66:813-827. [PMID: 29315804 DOI: 10.1002/glia.23286] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/08/2017] [Accepted: 12/11/2017] [Indexed: 01/03/2023]
Abstract
Early white matter (WM) changes are common in dementia and may contribute to functional decline. We here examine this phenomenon in an induced dementia model for the first time. We report a novel and selective form of myelin injury as the first manifestation of tauopathy in the adult central nervous system. Myelin pathology rapidly followed the induction of a P301 tau mutation associated with fronto-temporal dementia in humans (rTG4510 line). Damage involved focal disruption of the ad-axonal myelin lamella and internal oligodendrocyte tongue process, followed by myelin remodeling with features of re-myelination that included myelin thinning and internodal shortening. The evolution of the re-myelinated phenotype was complete in the molecular layer of the dentate gyrus after 1 month and in the optic nerve (ON) after 9 months of transgene induction and proceeded in the absence of actual demyelination, reactive glial changes or inflammatory response. The initial rapid myelin pathology was associated with loss of WM function and performance decline in a novel recognition test and both these effects largely reversed during the myelin re-modeling phase. The initial phase of myelin injury was accompanied by disruption of the vesicle population present in the axoplasm of hippocampal and ON axons. Axoplasmic vesicle release is significant for the regulation of myelin plasticity and disruption of this pathway may underlie the myelin damage and remodeling evoked by tauopathy. WM dysfunction early in tauopathy will disorder neural circuits, the current findings suggest this event may make a significant contribution to early clinical deficit in dementia.
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Affiliation(s)
| | | | - Angelo O Rosa
- Plymouth Electron Microscopy Centre, University of Plymouth, Plymouth, United Kingdom
| | - Katrina Cowan
- Peninsula School of Medicine and Dentistry, University of Plymouth, PUPSMD, Plymouth, United Kingdom
| | - Peter Bond
- Plymouth Electron Microscopy Centre, University of Plymouth, Plymouth, United Kingdom
| | - Oleg Anichtchik
- Peninsula School of Medicine and Dentistry, University of Plymouth, PUPSMD, Plymouth, United Kingdom
| | - Robert Fern
- Peninsula School of Medicine and Dentistry, University of Plymouth, PUPSMD, Plymouth, United Kingdom
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15
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Back SA. White matter injury in the preterm infant: pathology and mechanisms. Acta Neuropathol 2017; 134:331-349. [PMID: 28534077 PMCID: PMC5973818 DOI: 10.1007/s00401-017-1718-6] [Citation(s) in RCA: 266] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/27/2017] [Accepted: 04/29/2017] [Indexed: 12/22/2022]
Abstract
The human preterm brain is particularly susceptible to cerebral white matter injury (WMI) that disrupts the normal progression of developmental myelination. Advances in the care of preterm infants have resulted in a sustained reduction in the severity of WMI that has shifted from more severe focal necrotic lesions to milder diffuse WMI. Nevertheless, WMI remains a global health problem and the most common cause of chronic neurological morbidity from cerebral palsy and diverse neurobehavioral disabilities. Diffuse WMI involves maturation-dependent vulnerability of the oligodendrocyte (OL) lineage with selective degeneration of late oligodendrocyte progenitors (preOLs) triggered by oxidative stress and other insults. The magnitude and distribution of diffuse WMI are related to both the timing of appearance and regional distribution of susceptible preOLs. Diffuse WMI disrupts the normal progression of OL lineage maturation and myelination through aberrant mechanisms of regeneration and repair. PreOL degeneration is accompanied by early robust proliferation of OL progenitors that regenerate and augment the preOL pool available to generate myelinating OLs. However, newly generated preOLs fail to differentiate and initiate myelination along their normal developmental trajectory despite the presence of numerous intact-appearing axons. Disrupted preOL maturation is accompanied by diffuse gliosis and disturbances in the composition of the extracellular matrix and is mediated in part by inhibitory factors derived from reactive astrocytes. Signaling pathways implicated in disrupted myelination include those mediated by Notch, WNT-beta catenin, and hyaluronan. Hence, there exists a potentially broad but still poorly defined developmental window for interventions to promote white matter repair and myelination and potentially reverses the widespread disturbances in cerebral gray matter growth that accompanies WMI.
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Affiliation(s)
- Stephen A Back
- Division of Pediatric Neuroscience, Departments of Pediatrics and Neurology, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Rd, Portland, OR, 97239-3098, USA.
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16
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Wang HW, Wu B, Liu J, Liu F, Wu XH, Ge MM. [Quantitative evaluation of white matter development in fetus with growth restriction by diffusion tensor imaging]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2017. [PMID: 28774363 DOI: 10.7499/j.issn.1008-8830.2017.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To investigate whether fetal growth restriction (FGR) has an adverse effect on white matter development. METHODS A total of 28 full-term small for gestational age (SGA) infants were enrolled as study subjects and 15 full-term appropriate for gestational age infants were enrolled as control group. Conventional head magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were performed for all infants. The white matter was divided into 122 regions. The two groups were compared in terms of fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity of different brain regions. RESULTS Compared with the control group, the SGA group had a significantly lower fractional anisotropy in 16 brain regions (P<0.01), a significantly higher mean diffusivity in 7 brain regions (P<0.05), a significantly higher axial diffusivity in 8 brain regions (P<0.05), and a significantly higher radial diffusivity in 16 brain regions (P<0.05). CONCLUSIONS FGR may cause abnormalities in the maturity and integrity of white matter fiber tracts.
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Affiliation(s)
- Hua-Wei Wang
- Department of Neonatal Intensive Care Unite, Bayi Children's Hospital, Army General Hospital of the Chinese People Liberation Army, Beijing 100700, China.
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17
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Functional thalamocortical connectivity development and alterations in preterm infants during the neonatal period. Neuroscience 2017; 356:22-34. [PMID: 28526574 DOI: 10.1016/j.neuroscience.2017.05.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 05/03/2017] [Accepted: 05/08/2017] [Indexed: 01/25/2023]
Abstract
The thalamus is one of the most commonly affected brain regions in preterm infants, particularly in infants with white matter lesions (WML). The aim of this paper is to explore the development and alterations of the functional thalamocortical connectivity in preterm infants with and without punctate white matter lesions (PWMLs) during the period before term equivalent age (TEA). In this study, twenty-two normal preterm infants (NP), twenty-two preterm infants with PWMLs and thirty-one full-term control infants (FT) were enrolled. Thalamus parcellation was performed based on partial correlation between the thalamus and seven well-recognized infant networks obtained from independent component analysis (ICA), and thalamocortical connectivity was further reconstructed between the defined thalamus clusters and the whole brain. Thalamo-salience (SA) and thalamo-sensorimotor (SM) connectivity were predominantly identified, while other types of thalamocortical connectivity remained largely limited during the neonatal period. Both preterm groups exhibited prominent development in thalamo-SA and thalamo-SM connectivity during this period. Compared with NP infants, PWML infants demonstrated increased connectivity in the parietal area in thalamo-SA connectivity but no significant differences in thalamo-SM connectivity. Our results reveal that compared with NP infants, PWML infants exhibit slightly altered thalamo-SA connectivity, and this alteration is deduced to be functional compensations for inefficient thalamocortical processing due to PWMLs.
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18
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Ghate D, Vedanarayanan V, Kamour A, Corbett JJ, Kedar S. Optic nerve morphology as marker for disease severity in cerebral palsy of perinatal origin. J Neurol Sci 2016; 368:25-31. [DOI: 10.1016/j.jns.2016.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/07/2016] [Accepted: 06/12/2016] [Indexed: 11/29/2022]
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19
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Quraishe S, Wyttenbach A, Matinyarare N, Perry VH, Fern R, O'Connor V. Selective and compartmentalized myelin expression of HspB5. Neuroscience 2015; 316:130-42. [PMID: 26718604 DOI: 10.1016/j.neuroscience.2015.12.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/17/2015] [Accepted: 12/17/2015] [Indexed: 11/26/2022]
Abstract
In the present study, we reveal myelin-specific expression and targeting of mRNA and biochemical pools of HspB5 in the mouse CNS. Our observations are based on in situ hybridization, electron microscopy and co-localization with 2',3'-Cyclic-Nucleotide 3'-Phosphodiesterase (CNPase), reinforcing this myelin-selective expression. HspB5 mRNA might be targeted to these structures based on its presence in discrete clusters resembling RNA granules and the presence of a putative RNA transport signal. Further, sub-cellular fractionation of myelin membranes reveals a distinct sub-compartment-specific association and detergent solubility of HspB5. This is akin to other abundant myelin proteins and is consistent with HspB5's association with cytoskeletal/membrane assemblies. Oligodendrocytes have a pivotal role in supporting axonal function via generating and segregating the ensheathing myelin. This specialization places extreme structural and metabolic demands on this glial cell type. Our observations place HspB5 in oligodendrocytes which may require selective and specific chaperone capabilities to maintain normal function and neuronal support.
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Affiliation(s)
- S Quraishe
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, Building 85, University of Southampton, Southampton SO17 1BJ, UK.
| | - A Wyttenbach
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, Building 85, University of Southampton, Southampton SO17 1BJ, UK
| | - N Matinyarare
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, Building 85, University of Southampton, Southampton SO17 1BJ, UK
| | - V H Perry
- Centre for Biological Sciences, Mailpoint 840 (room LD80b), Level D Laboratories and Pathology Block, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK
| | - R Fern
- Peninsula School of Medicine and Dentistry, University of Plymouth, Devon, PL4 8AA, UK
| | - V O'Connor
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, Building 85, University of Southampton, Southampton SO17 1BJ, UK
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20
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Penn AA, Gressens P, Fleiss B, Back SA, Gallo V. Controversies in preterm brain injury. Neurobiol Dis 2015; 92:90-101. [PMID: 26477300 DOI: 10.1016/j.nbd.2015.10.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/08/2015] [Accepted: 10/14/2015] [Indexed: 01/24/2023] Open
Abstract
In this review, we highlight critical unresolved questions in the etiology and mechanisms causing preterm brain injury. Involvement of neurons, glia, endogenous factors and exogenous exposures is considered. The structural and functional correlates of interrupted development and injury in the premature brain are under active investigation, with the hope that the cellular and molecular mechanisms underlying developmental abnormalities in the human preterm brain can be understood, prevented or repaired.
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Affiliation(s)
- Anna A Penn
- Fetal Medicine Institute, Neonatology, Center for Neuroscience Research, Children's National Medical Center, George Washington University School of Medicine, Washington, DC, USA.
| | - Pierre Gressens
- Univ Paris Diderot, Sorbonne Paris Cité, UMRS 1141, Paris, France; Centre for the Developing Brain, King's College, St Thomas' Campus, London, UK
| | - Bobbi Fleiss
- Univ Paris Diderot, Sorbonne Paris Cité, UMRS 1141, Paris, France; Centre for the Developing Brain, King's College, St Thomas' Campus, London, UK
| | - Stephen A Back
- Departments of Pediatrics and Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Medical Center, George Washington University School of Medicine, Washington, DC, USA
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21
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Back SA. Brain Injury in the Preterm Infant: New Horizons for Pathogenesis and Prevention. Pediatr Neurol 2015; 53:185-92. [PMID: 26302698 PMCID: PMC4550810 DOI: 10.1016/j.pediatrneurol.2015.04.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/24/2015] [Accepted: 04/12/2015] [Indexed: 10/23/2022]
Abstract
Preterm neonates are surviving with a milder spectrum of motor and cognitive disabilities that appear to be related to widespread disturbances in cell maturation that target cerebral gray and white matter. Whereas the preterm brain was previously at high risk for destructive lesions, preterm survivors now commonly display less severe injury that is associated with aberrant regeneration and repair responses that result in reduced cerebral growth. Impaired cerebral white matter growth is related to myelination disturbances that are initiated by acute death of premyelinating oligodendrocytes, but are followed by rapid regeneration of premyelinating oligodendrocytes that fail to normally mature to myelinating cells. Although immature neurons are more resistant to cell death than mature neurons, they display widespread disturbances in maturation of their dendritic arbors and synapses, which further contributes to impaired cerebral growth. Thus, even more mild cerebral injury involves disrupted repair mechanisms in which neurons and premyelinating oligodendrocytes fail to fully mature during a critical window in development of neural circuitry. These recently recognized distinct forms of cerebral gray and white matter dysmaturation raise new diagnostic challenges and suggest new therapeutic strategies to promote brain growth and repair.
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Affiliation(s)
- Stephen A. Back
- Departments of Pediatrics and Neurology, Oregon Health & Science University, Portland, Oregon, U.S.A
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22
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Huria T, Beeraka NM, Al-Ghamdi B, Fern R. Premyelinated central axons express neurotoxic NMDA receptors: relevance to early developing white-matter injury. J Cereb Blood Flow Metab 2015; 35:543-53. [PMID: 25515212 PMCID: PMC4420873 DOI: 10.1038/jcbfm.2014.227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/12/2014] [Accepted: 11/19/2014] [Indexed: 01/05/2023]
Abstract
Ischemic-type injury to developing white matter is associated with the significant clinical condition cerebral palsy and with the cognitive deficits associated with premature birth. Premyelinated axons are the major cellular component of fetal white matter and loss of axon function underlies the disability, but the cellular mechanisms producing ischemic injury to premyelinated axons have not previously been described. Injury was found to require longer periods of modelled ischemia than at latter developmental points. Ischemia produced initial hyperexcitability in axons followed by loss of function after Na(+) and Ca(2+) influx. N-methyl-D-aspartate- (NMDA) type glutamate receptor (GluR) agonists potentiated axon injury while antagonists were protective. The NMDA GluR obligatory Nr1 subunit colocalized with markers of small premyelinated axons and expression was found at focal regions of axon injury. Ischemic injury of glial cells present in early developing white matter was NMDA GluR independent. Axons in human postconception week 18 to 23 white matter had a uniform prediameter expansion phenotype and postembedded immuno-gold labelling showed Nr1 subunit expression on the membrane of these axons, demonstrating a shared key neuropathologic feature with the rodent model. Premyelinated central axons therefore express high levels of functional NMDA GluRs that confer sensitivity to ischemic injury.
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Affiliation(s)
- Tahani Huria
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, UK
| | | | - Badrah Al-Ghamdi
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, UK
| | - Robert Fern
- Peninsula School of Medicine and Dentistry, University of Plymouth, John Bull Building, Research Way, Plymouth, UK
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23
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Wisnowski JL, Ceschin RC, Choi SY, Schmithorst VJ, Painter MJ, Nelson MD, Blüml S, Panigrahy A. Reduced thalamic volume in preterm infants is associated with abnormal white matter metabolism independent of injury. Neuroradiology 2015; 57:515-25. [PMID: 25666231 DOI: 10.1007/s00234-015-1495-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 01/21/2015] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Altered thalamocortical development is hypothesized to be a key substrate underlying neurodevelopmental disabilities in preterm infants. However, the pathogenesis of this abnormality is not well-understood. We combined magnetic resonance spectroscopy of the parietal white matter and morphometric analyses of the thalamus to investigate the association between white matter metabolism and thalamic volume and tested the hypothesis that thalamic volume would be associated with diminished N-acetyl-aspartate (NAA), a measure of neuronal/axonal maturation, independent of white matter injury. METHODS Data from 106 preterm infants (mean gestational age at birth: 31.0 weeks ± 4.3; range 23-36 weeks) who underwent MR examinations under clinical indications were included in this study. RESULTS Linear regression analyses demonstrated a significant association between parietal white matter NAA concentration and thalamic volume. This effect was above and beyond the effect of white matter injury and age at MRI and remained significant even when preterm infants with punctate white matter lesions (pWMLs) were excluded from the analysis. Furthermore, choline, and among the preterm infants without pWMLs, lactate concentrations were also associated with thalamic volume. Of note, the associations between NAA and choline concentration and thalamic volume remained significant even when the sample was restricted to neonates who were term-equivalent age or older. CONCLUSION These observations provide convergent evidence of a neuroimaging phenotype characterized by widespread abnormal thalamocortical development and suggest that the pathogenesis may involve impaired axonal maturation.
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Affiliation(s)
- Jessica L Wisnowski
- Department of Radiology, Children's Hospital Los Angeles, 4650 Sunset Blvd., MS #81, Los Angeles, CA, 90027, USA,
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24
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Ball G, Pazderova L, Chew A, Tusor N, Merchant N, Arichi T, Allsop JM, Cowan FM, Edwards AD, Counsell SJ. Thalamocortical Connectivity Predicts Cognition in Children Born Preterm. Cereb Cortex 2015; 25:4310-8. [PMID: 25596587 PMCID: PMC4816783 DOI: 10.1093/cercor/bhu331] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Thalamocortical connections are: essential for brain function, established early in development, and significantly impaired following preterm birth. Impaired cognitive abilities in preterm infants may be related to disruptions in thalamocortical connectivity. The aim of this study was to test the hypothesis: thalamocortical connectivity in the preterm brain at term-equivalent is correlated with cognitive performance in early childhood. We examined 57 infants who were born <35 weeks gestational age (GA) and had no evidence of focal abnormality on magnetic resonance imaging (MRI). Infants underwent diffusion MRI at term and cognitive performance at 2 years was assessed using the Bayley III scales of Infant and Toddler development. Cognitive scores at 2 years were correlated with structural connectivity between the thalamus and extensive cortical regions at term. Mean thalamocortical connectivity across the whole cortex explained 11% of the variance in cognitive scores at 2 years. The inclusion of GA at birth and parental socioeconomic group in the model explained 30% of the variance in subsequent cognitive performance. Identifying impairments in thalamocortical connectivity as early as term equivalent can help identify those infants at risk of subsequent cognitive delay and may be useful to assess efficacy of potential treatments at an early age.
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Affiliation(s)
- Gareth Ball
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Libuse Pazderova
- Department of Paediatrics, Imperial College London, Hammersmith Hospital, W12 0HS, UK
| | - Andrew Chew
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Nora Tusor
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Nazakat Merchant
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Tomoki Arichi
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Joanna M Allsop
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Frances M Cowan
- Department of Paediatrics, Imperial College London, Hammersmith Hospital, W12 0HS, UK
| | - A David Edwards
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
| | - Serena J Counsell
- Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas' Hospital, SE1 7EH, UK
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25
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Zhu Y, Wendler CC, Shi O, Rivkees SA. Diazoxide promotes oligodendrocyte differentiation in neonatal brain in normoxia and chronic sublethal hypoxia. Brain Res 2014; 1586:64-72. [PMID: 25157906 DOI: 10.1016/j.brainres.2014.08.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/07/2014] [Accepted: 08/16/2014] [Indexed: 11/28/2022]
Abstract
Periventricular white matter injury (PWMI) is the most common cause of brain injury in preterm infants. It is believed that loss of late oligodendrocyte progenitor cells (OPCs) and disrupted maturation of oligodendrocytes contributes to defective myelination in PWMI. At present, no clinically approved drugs are available for treating PWMI. Previously, we found that diazoxide promotes myelination and attenuates brain injury in the chronic sublethal hypoxia model of PWMI. In this study, we investigated the mechanisms by which diazoxide promotes myelination. We observed that diazoxide increases the ratio of differentiated oligodendrocytes in the cerebral white matter, promotes the expression of differentiation-associated transcriptional factors Nkx2.2 and Sox10, and increases the expression of myelin genes CNP and MBP. These results show that diazoxide promotes oligodendrocyte differentiation in the developing brain.
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Affiliation(s)
- Ying Zhu
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL 32610, United States
| | - Christopher C Wendler
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL 32610, United States
| | - Olivia Shi
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL 32610, United States
| | - Scott A Rivkees
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL 32610, United States.
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26
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Fern RF, Matute C, Stys PK. White matter injury: Ischemic and nonischemic. Glia 2014; 62:1780-9. [PMID: 25043122 DOI: 10.1002/glia.22722] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 06/18/2014] [Accepted: 06/30/2014] [Indexed: 02/02/2023]
Abstract
Ischemic pathologies of white matter (WM) include a large proportion of stroke and developmental lesions while multiple sclerosis (MS) is the archetype nonischemic pathology. Growing evidence suggests other important diseases including neurodegenerative and psychiatric disorders also involve a significant WM component. Axonal, oligodendroglial, and astroglial damage proceed via distinct mechanisms in ischemic WM and these mechanisms evolve dramatically with maturation. Axons may pass through four developmental stages where the pattern of membrane protein expression influences how the structure responds to ischemia; WM astrocytes pass through at least two and differ significantly in their ischemia tolerance from grey matter astrocytes; oligodendroglia pass through at least three, with the highly ischemia intolerant pre-oligodendrocyte (pre-Oli) stage linking the less sensitive precursor and mature phenotypes. Neurotransmitters play a central role in WM pathology at all ages. Glutamate excitotoxicity in WM has both necrotic and apoptotic components; the latter mediated by intracellular pathways which differ between receptor types. ATP excitotoxicity may be largely mediated by the P2X7 receptor and also has both necrotic and apoptotic components. Interplay between microglia and other cell types is a critical element in the injury process. A growing appreciation of the significance of WM injury for nonischemic neurological disorders is currently stimulating research into mechanisms; with curious similarities being found with those operating during ischemia. A good example is traumatic brain injury, where axonal pathology can proceed via almost identical pathways to those described during acute ischemia.
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Affiliation(s)
- Robert F Fern
- Peninsula School of Medicine and Dentistry, University of Plymouth, United Kingdom
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27
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Ortinau C, Neil J. The neuroanatomy of prematurity: Normal brain development and the impact of preterm birth. Clin Anat 2014; 28:168-83. [DOI: 10.1002/ca.22430] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/09/2014] [Indexed: 12/17/2022]
Affiliation(s)
- Cynthia Ortinau
- Department of Pediatric Newborn Medicine; Brigham and Women's Hospital, Harvard Medical School; Boston, Massachusetts USA
| | - Jeffrey Neil
- Departments of Neurology and Radiology; Boston Children's Hospital, Harvard Medical School; Boston, Massachusetts USA
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28
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Volpe JJ. Encephalopathy of congenital heart disease- destructive and developmental effects intertwined. J Pediatr 2014; 164:962-5. [PMID: 24529617 DOI: 10.1016/j.jpeds.2014.01.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/03/2014] [Indexed: 11/15/2022]
Affiliation(s)
- Joseph J Volpe
- Bronson Crothers Distinguished Professor of Neurology, Harvard Medical School Boston Children's Hospital, Boston, Massachusetts.
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29
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Drobyshevsky A, Jiang R, Lin L, Derrick M, Luo K, Back SA, Tan S. Unmyelinated axon loss with postnatal hypertonia after fetal hypoxia. Ann Neurol 2014; 75:533-41. [PMID: 24633673 PMCID: PMC5975649 DOI: 10.1002/ana.24115] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/28/2022]
Abstract
OBJECTIVE White matter (WM) injury due to myelination defects is believed to be responsible for the motor deficits seen in cerebral palsy. We tested the hypothesis that the predominant injury is to functional electrical connectivity in unmyelinated WM fibers by conducting a longitudinal study of central WM tracts in newborn rabbit kits with hypertonia in our model of cerebral palsy. METHODS Pregnant rabbits at 70% gestation underwent 40-minute uterine ischemia. Motor deficits in newborn kits, including muscle hypertonia, were assessed by neurobehavioral testing. Major central WM tracts, including internal capsule, corpus callosum, anterior commissure, and fimbria hippocampi, were investigated for structural and functional injury using diffusion tensor magnetic resonance imaging (MRI), electrophysiological recordings of fiber conductivity in perfused brain slices, electron microscopy, and immunohistochemistry of oligodendrocyte lineage. RESULTS Motor deficits were observed on postnatal day 1 (P1) when WM tracts were unmyelinated. Myelination occurred later and was obvious by P18. Hypertonia was associated with microstructural WM injury and unmyelinated axon loss at P1, diagnosed by diffusion tensor MRI and electron microscopy. Axonal conductivity from electrophysiological recordings in hypertonic P18 kits decreased only in unmyelinated fibers, despite a loss in both myelinated and unmyelinated axons. INTERPRETATION Motor deficits in cerebral palsy were associated with loss of unmyelinated WM tracts. The contribution of injury to myelinated fibers that was observed at P18 is probably a secondary etiological factor in the motor and sensory deficits in the rabbit model of cerebral palsy.
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Affiliation(s)
- Alexander Drobyshevsky
- Department of Pediatrics, NorthShore University HealthSystem Research Institute, Evanston, IL
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Back SA, Miller SP. Brain injury in premature neonates: A primary cerebral dysmaturation disorder? Ann Neurol 2014; 75:469-86. [PMID: 24615937 PMCID: PMC5989572 DOI: 10.1002/ana.24132] [Citation(s) in RCA: 238] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 12/11/2022]
Abstract
With advances in neonatal care, preterm neonates are surviving with an evolving constellation of motor and cognitive disabilities that appear to be related to widespread cellular maturational disturbances that target cerebral gray and white matter. Whereas preterm infants were previously at high risk for destructive brain lesions that resulted in cystic white matter injury and secondary cortical and subcortical gray matter degeneration, contemporary cohorts of preterm survivors commonly display less severe injury that does not appear to involve pronounced glial or neuronal loss. Nevertheless, these milder forms of injury are also associated with reduced cerebral growth. Recent human and experimental studies support that impaired cerebral growth is related to disparate responses in gray and white matter. Myelination disturbances in cerebral white matter are related to aberrant regeneration and repair responses to acute death of premyelinating late oligodendrocyte progenitors (preOLs). In response to preOL death, early oligodendrocyte progenitors rapidly proliferate and differentiate, but the regenerated preOLs fail to normally mature to myelinating cells required for white matter growth. Although immature neurons appear to be more resistant to cell death from hypoxia-ischemia than glia, they display widespread disturbances in maturation of their dendritic arbors, which further contribute to impaired cerebral growth. These complex and disparate responses of neurons and preOLs thus result in large numbers of cells that fail to fully mature during a critical window in development of neural circuitry. These recently recognized forms of cerebral gray and white matter dysmaturation raise new diagnostic challenges and suggest new therapeutic directions centered on reversal of the processes that promote dysmaturation.
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Affiliation(s)
- Stephen A Back
- Departments of Pediatrics, Oregon Health and Science University, Portland; Departments of Neurology, Oregon Health and Science University, Portland
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Back SA, Rosenberg PA. Pathophysiology of glia in perinatal white matter injury. Glia 2014; 62:1790-815. [PMID: 24687630 DOI: 10.1002/glia.22658] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/13/2014] [Accepted: 02/27/2014] [Indexed: 12/12/2022]
Abstract
Injury to the preterm brain has a particular predilection for cerebral white matter. White matter injury (WMI) is the most common cause of brain injury in preterm infants and a major cause of chronic neurological morbidity including cerebral palsy. Factors that predispose to WMI include cerebral oxygenation disturbances and maternal-fetal infection. During the acute phase of WMI, pronounced oxidative damage occurs that targets late oligodendrocyte progenitors (pre-OLs). The developmental predilection for WMI to occur during prematurity appears to be related to both the timing of appearance and regional distribution of susceptible pre-OLs that are vulnerable to a variety of chemical mediators including reactive oxygen species, glutamate, cytokines, and adenosine. During the chronic phase of WMI, the white matter displays abberant regeneration and repair responses. Early OL progenitors respond to WMI with a rapid robust proliferative response that results in a several fold regeneration of pre-OLs that fail to terminally differentiate along their normal developmental time course. Pre-OL maturation arrest appears to be related in part to inhibitory factors that derive from reactive astrocytes in chronic lesions. Recent high field magnetic resonance imaging (MRI) data support that three distinct forms of chronic WMI exist, each of which displays unique MRI and histopathological features. These findings suggest the possibility that therapies directed at myelin regeneration and repair could be initiated early after WMI and monitored over time. These new mechanisms of acute and chronic WMI provide access to a variety of new strategies to prevent or promote repair of WMI in premature infants.
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Affiliation(s)
- Stephen A Back
- Department of Pediatrics, Oregon Health and Science University, Portland, Oregon; Department of Neurology, Oregon Health and Science University, Portland, Oregon
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Central axons preparing to myelinate are highly sensitive to ischemic injury. Ann Neurol 2014. [DOI: 10.1002/ana.24129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Back SA. Cerebral white and gray matter injury in newborns: new insights into pathophysiology and management. Clin Perinatol 2014; 41:1-24. [PMID: 24524444 PMCID: PMC3947650 DOI: 10.1016/j.clp.2013.11.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Increasing numbers of preterm neonates survive with motor and cognitive disabilities related to less destructive forms of cerebral injury that still result in reduced cerebral growth. White matter injury results in myelination disturbances related to aberrant responses to death of pre-myelinating oligodendrocytes (preOLs). PreOLs are rapidly regenerated but fail to mature to myelinating cells. Although immature projection neurons are more resistant to hypoxia-ischemia than preOLs, they display widespread disturbances in dendritic arbor maturation, which provides an explanation for impaired cerebral growth. Thus, large numbers of cells fail to fully mature during a critical window in development of neural circuitry. These recently recognized forms of cerebral gray and white matter dysmaturation suggest new therapeutic directions centered on reversal of the processes that promote dysmaturation.
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Affiliation(s)
- Stephen A. Back
- Professor of Pediatrics and Neurology Oregon Health & Science University Clyde and Elda Munson Professor of Pediatric Research Director, Neuroscience Section, Pape' Family Pediatric Research Institute
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Harper RM, Kumar R, Macey PM, Woo MA, Ogren JA. Affective brain areas and sleep-disordered breathing. PROGRESS IN BRAIN RESEARCH 2014; 209:275-93. [PMID: 24746053 DOI: 10.1016/b978-0-444-63274-6.00014-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The neural damage accompanying the hypoxia, reduced perfusion, and other consequences of sleep-disordered breathing, found in obstructive sleep apnea, heart failure, and congenital central hypoventilation syndrome (CCHS), appears in areas that serve multiple functions, including emotional drives to breathe, and involve systems that serve affective, cardiovascular, and breathing roles. The damage, assessed with structural magnetic resonance imaging (MRI) procedures, shows tissue loss or water content and diffusion changes indicative of injury, and impaired axonal integrity between structures; damage is preferentially unilateral. Functional MRI responses in affected areas also are time- or amplitude-distorted to ventilatory or autonomic challenges. Among the structures injured are the insular, cingulate, and ventral medial prefrontal cortices, as well as cerebellar deep nuclei and cortex, anterior hypothalamus, caudal raphé, ventrolateral medulla, portions of the basal ganglia and, in CCHS, the locus coeruleus. Caudal raphé and locus coeruleus injury have the potential to modify serotonergic and adrenergic modulation of upper airway and arousal characteristics, as well as affective drive to breathe. Since both axons and gray matter show injury, the consequences to function, especially to autonomic, cognitive, and mood regulation, are major. Several of the affected rostral sites mediate aspects of dyspnea, especially in CCHS, while others participate in initiation of inspiration after central breathing pauses, and the medullary injury can impair baroreflex and breathing control. The ancillary injury associated with sleep-disordered breathing to central structures can elicit multiple other distortions in cardiovascular, cognitive, and emotional functions in addition to effects on breathing regulation.
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Affiliation(s)
- Ronald M Harper
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA; Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, USA.
| | - Rajesh Kumar
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA; Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, USA
| | - Paul M Macey
- Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, USA; UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, USA
| | - Mary A Woo
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, USA
| | - Jennifer A Ogren
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, USA
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Astrocytes and microglia in acute cerebral injury underlying cerebral palsy associated with preterm birth. Pediatr Res 2014; 75:234-40. [PMID: 24336433 DOI: 10.1038/pr.2013.188] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 07/11/2013] [Indexed: 02/06/2023]
Abstract
Cerebral palsy is one of the most devastating consequences of brain injury around the time of birth, and nearly a third of cases are now associated with premature birth. Compared with term babies, preterm babies have an increased incidence of complications that may increase the risk of disability, such as intraventricular hemorrhage, periventricular leukomalacia, sepsis, and necrotizing enterocolitis. The response to injury is highly dependent on brain maturity, and although cellular vulnerability is well documented, there is now evidence that premyelinating axons are also particularly sensitive to ischemic injury. In this review, we will explore recent evidence highlighting a central role for glia in mediating increased risk of disability in premature infants, including excessive activation of microglia and opening of astrocytic gap junction hemichannels in spreading injury after brain ischemia, in part likely involving release of adenosine triphosphate (ATP) and overactivation of purinergic receptors, particularly in white matter. We propose the hypothesis that inflammation-induced opening of connexin hemichannels is a key regulating event that initiates a vicious circle of excessive ATP release, which in turn propagates activation of purinergic receptors on microglia and astrocytes. This suggests that developing effective neuroprotective strategies for preterm infants requires a detailed understanding of glial responses.
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Schumacher M, Mattern C, Ghoumari A, Oudinet JP, Liere P, Labombarda F, Sitruk-Ware R, De Nicola AF, Guennoun R. Revisiting the roles of progesterone and allopregnanolone in the nervous system: resurgence of the progesterone receptors. Prog Neurobiol 2013; 113:6-39. [PMID: 24172649 DOI: 10.1016/j.pneurobio.2013.09.004] [Citation(s) in RCA: 245] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/15/2013] [Accepted: 09/21/2013] [Indexed: 02/08/2023]
Abstract
Progesterone is commonly considered as a female reproductive hormone and is well-known for its role in pregnancy. It is less well appreciated that progesterone and its metabolite allopregnanolone are also male hormones, as they are produced in both sexes by the adrenal glands. In addition, they are synthesized within the nervous system. Progesterone and allopregnanolone are associated with adaptation to stress, and increased production of progesterone within the brain may be part of the response of neural cells to injury. Progesterone receptors (PR) are widely distributed throughout the brain, but their study has been mainly limited to the hypothalamus and reproductive functions, and the extra-hypothalamic receptors have been neglected. This lack of information about brain functions of PR is unexpected, as the protective and trophic effects of progesterone are much investigated, and as the therapeutic potential of progesterone as a neuroprotective and promyelinating agent is currently being assessed in clinical trials. The little attention devoted to the brain functions of PR may relate to the widely accepted assumption that non-reproductive actions of progesterone may be mainly mediated by allopregnanolone, which does not bind to PR, but acts as a potent positive modulator of γ-aminobutyric acid type A (GABA(A) receptors. The aim of this review is to critically discuss effects of progesterone on the nervous system via PR, and of allopregnanolone via its modulation of GABA(A) receptors, with main focus on the brain.
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Affiliation(s)
- M Schumacher
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France.
| | - C Mattern
- M et P Pharma AG, Emmetten, Switzerland
| | - A Ghoumari
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| | - J P Oudinet
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| | - P Liere
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| | - F Labombarda
- Instituto de Biologia y Medicina Experimental and University of Buenos Aires, Argentina
| | - R Sitruk-Ware
- Population Council and Rockefeller University, New York, USA
| | - A F De Nicola
- Instituto de Biologia y Medicina Experimental and University of Buenos Aires, Argentina
| | - R Guennoun
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
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