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Lv H, Wang Q, Liu F, Jin L, Ren P, Li L. A biochemical feedback signal for hypothermia treatment for neonatal hypoxic-ischemic encephalopathy: focusing on central nervous system proteins in biofluids. Front Pediatr 2024; 12:1288853. [PMID: 38766393 PMCID: PMC11100326 DOI: 10.3389/fped.2024.1288853] [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] [Received: 09/05/2023] [Accepted: 04/15/2024] [Indexed: 05/22/2024] Open
Abstract
Hypothermia has been widely used to treat moderate to severe neonatal hypoxic-ischemic encephalopathy (HIE), yet evaluating the effects of hypothermia relies on clinical neurology, neuroimaging, amplitude-integrated electroencephalography, and follow-up data on patient outcomes. Biomarkers of brain injury have been considered for estimating the effects of hypothermia. Proteins specific to the central nervous system (CNS) are components of nervous tissue, and once the CNS is damaged, these proteins are released into biofluids (cerebrospinal fluid, blood, urine, tears, saliva), and they can be used as markers of brain damage. Clinical reports have shown that CNS-specific marker proteins (CNSPs) were early expressed in biofluids after brain damage and formed unique biochemical profiles. As a result, these markers may serve as an indicator for screening brain injury in infants, monitoring disease progression, identifying damage region of brain, and assessing the efficacy of neuroprotective measures. In clinical work, we have found that there are few reports on using CNSPs as biological signals in hypothermia for neonatal HIE. The aim of this article is to review the classification, origin, biochemical composition, and physiological function of CNSPs with changes in their expression levels after hypothermia for neonatal HIE. Hopefully, this review will improve the awareness of CNSPs among pediatricians, and encourage future studies exploring the mechanisms behind the effects of hypothermia on these CNSPs, in order to reduce the adverse outcome of neonatal HIE.
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Affiliation(s)
- Hongyan Lv
- Department of Neonatology, Handan Maternal and Child Health Care Hospital, Handan, Hebei, China
- Department of Neonatal Pathology, Handan Maternal and Child Health Care Hospital, Handan, Hebei, China
| | - Qiuli Wang
- Department of Neonatology, Handan Maternal and Child Health Care Hospital, Handan, Hebei, China
| | - Fang Liu
- Department of Pediatrics, The 980 Hospital of the PLA Joint Logistics Support Force, Shijiazhuang, China
| | - Linhong Jin
- Department of Neonatology, Handan Maternal and Child Health Care Hospital, Handan, Hebei, China
| | - Pengshun Ren
- Department of Neonatology, Handan Maternal and Child Health Care Hospital, Handan, Hebei, China
| | - Lianxiang Li
- Department of Neonatal Pathology, Handan Maternal and Child Health Care Hospital, Handan, Hebei, China
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El-Dib M, Abend NS, Austin T, Boylan G, Chock V, Cilio MR, Greisen G, Hellström-Westas L, Lemmers P, Pellicer A, Pressler RM, Sansevere A, Tsuchida T, Vanhatalo S, Wusthoff CJ, Wintermark P, Aly H, Chang T, Chau V, Glass H, Lemmon M, Massaro A, Wusthoff C, deVeber G, Pardo A, McCaul MC. Neuromonitoring in neonatal critical care part I: neonatal encephalopathy and neonates with possible seizures. Pediatr Res 2022:10.1038/s41390-022-02393-1. [PMID: 36476747 DOI: 10.1038/s41390-022-02393-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/12/2022] [Accepted: 08/19/2022] [Indexed: 12/12/2022]
Abstract
The blooming of neonatal neurocritical care over the last decade reflects substantial advances in neuromonitoring and neuroprotection. The most commonly used brain monitoring tools in the neonatal intensive care unit (NICU) are amplitude integrated EEG (aEEG), full multichannel continuous EEG (cEEG), and near-infrared spectroscopy (NIRS). While some published guidelines address individual tools, there is no consensus on consistent, efficient, and beneficial use of these modalities in common NICU scenarios. This work reviews current evidence to assist decision making for best utilization of neuromonitoring modalities in neonates with encephalopathy or with possible seizures. Neuromonitoring approaches in extremely premature and critically ill neonates are discussed separately in the companion paper. IMPACT: Neuromonitoring techniques hold promise for improving neonatal care. For neonatal encephalopathy, aEEG can assist in screening for eligibility for therapeutic hypothermia, though should not be used to exclude otherwise eligible neonates. Continuous cEEG, aEEG and NIRS through rewarming can assist in prognostication. For neonates with possible seizures, cEEG is the gold standard for detection and diagnosis. If not available, aEEG as a screening tool is superior to clinical assessment alone. The use of seizure detection algorithms can help with timely seizures detection at the bedside.
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Affiliation(s)
- Mohamed El-Dib
- Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Nicholas S Abend
- Departments of Neurology and Pediatrics, Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Topun Austin
- Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - Geraldine Boylan
- INFANT Research Centre & Department of Paediatrics & Child Health, University College Cork, Cork, Ireland
| | - Valerie Chock
- Division of Neonatal and Developmental Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - M Roberta Cilio
- Department of Pediatrics, Division of Pediatric Neurology, Cliniques universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Gorm Greisen
- Department of Neonatology, Rigshospitalet, Copenhagen University Hospital & Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Lena Hellström-Westas
- Department of Women's and Children's Health, Uppsala University, and Division of Neonatology, Uppsala University Hospital, Uppsala, Sweden
| | - Petra Lemmers
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Adelina Pellicer
- Department of Neonatology, La Paz University Hospital, Madrid, Spain; Neonatology Group, IdiPAZ, Madrid, Spain
| | - Ronit M Pressler
- Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Trust, and Clinical Neuroscience, UCL- Great Ormond Street Institute of Child Health, London, UK
| | - Arnold Sansevere
- Department of Neurology and Pediatrics, George Washington University School of Medicine and Health Sciences; Children's National Hospital Division of Neurophysiology, Epilepsy and Critical Care, Washington, DC, USA
| | - Tammy Tsuchida
- Department of Neurology and Pediatrics, George Washington University School of Medicine and Health Sciences; Children's National Hospital Division of Neurophysiology, Epilepsy and Critical Care, Washington, DC, USA
| | - Sampsa Vanhatalo
- Department of Clinical Neurophysiology, Children's Hospital, BABA Center, Neuroscience Center/HILIFE, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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Brocard C, Belaroussi Y, Labat J, Delmas J, Brissaud O, Chateil JF. Brain MRI after therapeutic hypothermia in asphyxiated newborns: Predictive value at one year of imaging features. Eur J Radiol 2021; 139:109724. [PMID: 33932716 DOI: 10.1016/j.ejrad.2021.109724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/31/2021] [Accepted: 04/13/2021] [Indexed: 12/29/2022]
Abstract
PURPOSE To compare early brain MRI using a composite imaging score and outcome at one year in asphyxiated newborns treated by hypothermia. METHODS This retrospective study included for two years consecutive asphyxiated term newborns treated by hypothermia for hypoxic-ischemic encephalopathy, and who had brain MRI before day 8. Therapeutic hypothermia was initiated within the first 6 h of life and continued for 72 h. Imaging protocol included T1 and T2 sequences, diffusion-weighted imaging (DWI), evaluated with a specific composite score, and spectroscopy. Clinical evaluation was performed at one year of age, outcome was classified as favorable/unfavorable. The primary endpoint was the correlation between our MRI score and outcome with the definition of a threshold. The secondary endpoints were to find the most relevant criteria within the score and to evaluate objective signal measurements to support subjective criteria. RESULTS Among the 33 included patients, 9 died during the first days of life, 20 had a favorable outcome, 4 an unfavorable one. MRI score was correlated to a poor clinical outcome (p < 0.001). Most of the criteria within the score and spectroscopy results were relevant (p < 0.05). Cerebral edema was objectively assessed by the signal intensity ratio of white matter compared to cerebrospinal fluid (CSF) on T2-weighted images (p < 0.001). CONCLUSION MRI score was predictive of neurodevelopmental outcome at one year. The most relevant criteria within the score were DWI abnormalities in basal ganglia and thalami and loss of white-cortical grey matter differentiation. Signal intensity ratio between white matter and CSF higher than 0.75 supports the presence of edema.
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Affiliation(s)
- Clémentine Brocard
- Service d'imagerie anténatale, de l'enfant et de la femme, Hôpital Pellegrin, place Amélie Raba-Léon, F-33076, Bordeaux, France.
| | - Yaniss Belaroussi
- INSERM, Bordeaux Population Health Research Center, ISPED, Univ. Bordeaux, F-33076, Bordeaux, France; Service de chirurgie thoracique, Hôpital Haut-Lévêque, F-33604, Pessac, France.
| | - Justine Labat
- Service de réanimation pédiatrique, Hôpital Pellegrin, place Amélie Raba-Léon, F-33076, Bordeaux, France.
| | - Jean Delmas
- Service d'imagerie anténatale, de l'enfant et de la femme, Hôpital Pellegrin, place Amélie Raba-Léon, F-33076, Bordeaux, France.
| | - Olivier Brissaud
- Service de réanimation pédiatrique, Hôpital Pellegrin, place Amélie Raba-Léon, F-33076, Bordeaux, France.
| | - Jean-François Chateil
- Service d'imagerie anténatale, de l'enfant et de la femme, Hôpital Pellegrin, place Amélie Raba-Léon, F-33076, Bordeaux, France; CRMSB, UMR5536 CNRS/Univ. Bordeaux, F-33076, Bordeaux, France.
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Hamdy N, Eide S, Sun HS, Feng ZP. Animal models for neonatal brain injury induced by hypoxic ischemic conditions in rodents. Exp Neurol 2020; 334:113457. [PMID: 32889009 DOI: 10.1016/j.expneurol.2020.113457] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 02/06/2023]
Abstract
Neonatal hypoxia-ischemia and resulting encephalopathies are of significant concern. Intrapartum asphyxia is a leading cause of neonatal death globally. Among surviving infants, there remains a high incidence of hypoxic-ischemic encephalopathy due to neonatal hypoxic-ischemic brain injury, manifesting as mild conditions including attention deficit hyperactivity disorder, and debilitating disorders such as cerebral palsy. Various animal models of neonatal hypoxic brain injury have been implemented to explore cellular and molecular mechanisms, assess the potential of novel therapeutic strategies, and characterize the functional and behavioural correlates of injury. Each of the animal models has individual advantages and limitations. The present review looks at several widely-used and alternative rodent models of neonatal hypoxia and hypoxia-ischemia; it highlights their strengths and limitations, and their potential for continued and improved use.
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Affiliation(s)
- Nancy Hamdy
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Sarah Eide
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Hong-Shuo Sun
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
| | - Zhong-Ping Feng
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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5
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Abstract
Significant advances in the field of neonatal imaging has resulted in the generation of large complex data sets of relevant information for routine daily clinical practice, and basic and translational research. The evaluation of this data is a complex task for the neonatal imager who must distinguish normal and incidental findings from clinically significant abnormalities which are often adjunctive data points applicable to clinical evaluation and treatment. This review provides an overview of the imaging manifestations of disease processes commonly encountered in the neonatal brain. Since MRI is currently the highest yield technique for the diagnosis and characterization of the normal and abnormal brain, it is therefore the focus of the majority of this review. When applicable, discussion of some of the pertinent known pathophysiology and neuropathological aspects of disease processes are reviewed.
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Bale G, Mitra S, de Roever I, Sokolska M, Price D, Bainbridge A, Gunny R, Uria-Avellanal C, Kendall GS, Meek J, Robertson NJ, Tachtsidis I. Oxygen dependency of mitochondrial metabolism indicates outcome of newborn brain injury. J Cereb Blood Flow Metab 2019; 39:2035-2047. [PMID: 29775114 PMCID: PMC6775592 DOI: 10.1177/0271678x18777928] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is a need for a method of real-time assessment of brain metabolism during neonatal hypoxic-ischaemic encephalopathy (HIE). We have used broadband near-infrared spectroscopy (NIRS) to monitor cerebral oxygenation and metabolic changes in 50 neonates with HIE undergoing therapeutic hypothermia treatment. In 24 neonates, 54 episodes of spontaneous decreases in peripheral oxygen saturation (desaturations) were recorded between 6 and 81 h after birth. We observed differences in the cerebral metabolic responses to these episodes that were related to the predicted outcome of the injury, as determined by subsequent magnetic resonance spectroscopy derived lactate/N-acetyl-aspartate. We demonstrated that a strong relationship between cerebral metabolism (broadband NIRS-measured cytochrome-c-oxidase (CCO)) and cerebral oxygenation was associated with unfavourable outcome; this is likely to be due to a lower cerebral metabolic rate and mitochondrial dysfunction in severe encephalopathy. Specifically, a decrease in the brain tissue oxidation state of CCO greater than 0.06 µM per 1 µM brain haemoglobin oxygenation drop was able to predict the outcome with 64% sensitivity and 79% specificity (receiver operating characteristic area under the curve = 0.73). With further work on the implementation of this methodology, broadband NIRS has the potential to provide an early, cotside, non-invasive, clinically relevant metabolic marker of perinatal hypoxic-ischaemic injury.
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Affiliation(s)
- Gemma Bale
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Subhabrata Mitra
- Institute of Women's Health, University College London, London, UK
| | - Isabel de Roever
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Magdalena Sokolska
- Department of Medical Physics and Biomedical Engineering, University College London Hospital, London, UK
| | - David Price
- Department of Medical Physics and Biomedical Engineering, University College London Hospital, London, UK
| | - Alan Bainbridge
- Department of Medical Physics and Biomedical Engineering, University College London Hospital, London, UK
| | - Roxana Gunny
- Paediatric Neuroradiology, Great Ormond Street Hospital for Children, London, UK
| | | | - Giles S Kendall
- Neonatal Unit, University College London Hospital, London, UK
| | - Judith Meek
- Institute of Women's Health, University College London, London, UK
| | | | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
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7
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Abstract
Hypoxia-ischemia is a leading cause of morbidity and mortality in the perinatal period with an incidence of 1/4000 live births. Biochemical events such as energy failure, membrane depolarization, brain edema, an increase of neurotransmitter release and inhibition of uptake, an increase of intracellular Ca(2+), production of oxygen-free radicals, lipid peroxidation, and a decrease of blood flow are triggered by hypoxia-ischemia and may lead to brain dysfunction and neuronal death. These abnormalities can result in mental impairments, seizures, and permanent motor deficits, such as cerebral palsy. The physical and emotional strain that is placed on the children affected and their families is enormous. The care that these individuals need is not only confined to childhood, but rather extends throughout their entire life span, so it is very important to understand the pathophysiology that follows a hypoxic-ischemic insult. This review will highlight many of the mechanisms that lead to neuronal death and include the emerging area of white matter injury as well as the role of inflammation and will provide a summary of therapeutic strategies. Hypothermia and oxygen will also be discussed as treatments that currently lack a specific target in the hypoxic/ischemic cascade.
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Affiliation(s)
- John W Calvert
- Departments of Neurosurgery and Molecular and Cellular Physiology, Loma Linda University Medical Center, 11234 Anderson Street, Loma Linda, CA 92354, USA
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8
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Filippi L, Fiorini P, Daniotti M, Catarzi S, Savelli S, Fonda C, Bartalena L, Boldrini A, Giampietri M, Scaramuzzo R, Papoff P, Del Balzo F, Spalice A, la Marca G, Malvagia S, Della Bona ML, Donzelli G, Tinelli F, Cioni G, Pisano T, Falchi M, Guerrini R. Safety and efficacy of topiramate in neonates with hypoxic ischemic encephalopathy treated with hypothermia (NeoNATI). BMC Pediatr 2012; 12:144. [PMID: 22950861 PMCID: PMC3478965 DOI: 10.1186/1471-2431-12-144] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 08/31/2012] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Despite progresses in neonatal care, the mortality and the incidence of neuro-motor disability after perinatal asphyxia have failed to show substantial improvements. In countries with a high level of perinatal care, the incidence of asphyxia responsible for moderate or severe encephalopathy is still 2-3 per 1000 term newborns. Recent trials have demonstrated that moderate hypothermia, started within 6 hours after birth and protracted for 72 hours, can significantly improve survival and reduce neurologic impairment in neonates with hypoxic-ischemic encephalopathy. It is not currently known whether neuroprotective drugs can further improve the beneficial effects of hypothermia. Topiramate has been proven to reduce brain injury in animal models of neonatal hypoxic ischemic encephalopathy. However, the association of mild hypothermia and topiramate treatment has never been studied in human newborns. The objective of this research project is to evaluate, through a multicenter randomized controlled trial, whether the efficacy of moderate hypothermia can be increased by concomitant topiramate treatment. METHODS/DESIGN Term newborns (gestational age ≥ 36 weeks and birth weight ≥ 1800 g) with precocious metabolic, clinical and electroencephalographic (EEG) signs of hypoxic-ischemic encephalopathy will be randomized, according to their EEG pattern, to receive topiramate added to standard treatment with moderate hypothermia or standard treatment alone. Topiramate will be administered at 10 mg/kg once a day for the first 3 days of life. Topiramate concentrations will be measured on serial dried blood spots. 64 participants will be recruited in the study. To evaluate the safety of topiramate administration, cardiac and respiratory parameters will be continuously monitored. Blood samplings will be performed to check renal, liver and metabolic balance. To evaluate the efficacy of topiramate, the neurologic outcome of enrolled newborns will be evaluated by serial neurologic and neuroradiologic examinations. Visual function will be evaluated by means of behavioural standardized tests. DISCUSSION This pilot study will explore the possible therapeutic role of topiramate in combination with moderate hypothermia. Any favourable results of this research might open new perspectives about the reduction of cerebral damage in asphyxiated newborns.
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Affiliation(s)
- Luca Filippi
- Neonatal Intensive Care Unit, Medical Surgical Feto-Neonatal Department, A. Meyer University Children's Hospital, Viale Pieraccini, 24, I-50139, Florence, Italy.
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Abstract
Cerebral palsy is caused by injury or developmental disturbances to the immature brain and leads to substantial motor, cognitive, and learning deficits. In addition to developmental disruption associated with the initial insult to the immature brain, injury processes can persist for many months or years. We suggest that these tertiary mechanisms of damage might include persistent inflammation and epigenetic changes. We propose that these processes are implicit in prevention of endogenous repair and regeneration and predispose patients to development of future cognitive dysfunction and sensitisation to further injury. We suggest that treatment of tertiary mechanisms of damage might be possible by various means, including preventing the repressive effects of microglia and astrocyte over-activation, recapitulating developmentally permissive epigenetic conditions, and using cell therapies to stimulate repair and regeneration Recognition of tertiary mechanisms of damage might be the first step in a complex translational task to tailor safe and effective therapies that can be used to treat the already developmentally disrupted brain long after an insult.
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Molecular mechanisms of neonatal brain injury. Neurol Res Int 2012; 2012:506320. [PMID: 22363841 PMCID: PMC3272851 DOI: 10.1155/2012/506320] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 10/11/2011] [Indexed: 12/12/2022] Open
Abstract
Fetal/neonatal brain injury is an important cause of neurological disability. Hypoxia-ischemia and excitotoxicity are considered important insults, and, in spite of their acute nature, brain injury develops over a protracted time period during the primary, secondary, and tertiary phases. The concept that most of the injury develops with a delay after the insult makes it possible to provide effective neuroprotective treatment after the insult. Indeed, hypothermia applied within 6 hours after birth in neonatal encephalopathy reduces neurological disability in clinical trials. In order to develop the next generation of treatment, we need to know more about the pathophysiological mechanism during the secondary and tertiary phases of injury. We review some of the critical molecular events related to mitochondrial dysfunction and apoptosis during the secondary phase and report some recent evidence that intervention may be feasible also days-weeks after the insult.
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Ennen CS, Huisman TA, Savage WJ, Northington FJ, Jennings JM, Everett AD, Graham EM. Glial fibrillary acidic protein as a biomarker for neonatal hypoxic-ischemic encephalopathy treated with whole-body cooling. Am J Obstet Gynecol 2011; 205:251.e1-7. [PMID: 21784396 DOI: 10.1016/j.ajog.2011.06.025] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 05/05/2011] [Accepted: 06/07/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Glial fibrillary acidic protein (GFAP) is specific to astrocytes in the central nervous system. We hypothesized that serum GFAP would be increased in neonates with hypoxic-ischemic encephalopathy (HIE) treated with whole-body cooling. STUDY DESIGN We measured GFAP at birth and daily for up to 7 days for neonates in the intensive care unit. We compared neonates with HIE treated with whole-body cooling to gestational age-matched controls without neurological injury and neonates with HIE by brain abnormalities on magnetic resonance imaging (MRI). RESULTS Neonates with HIE had increased GFAP levels compared with controls. Neonates with HIE and abnormal brain imaging had elevated GFAP levels compared with neonates with HIE and normal imaging. CONCLUSION Serum GFAP levels during the first week of life were increased in neonates with HIE and were predictive of brain injury on MRI. Biomarkers such as GFAP could help triage neonates with HIE to treatment, measure treatment efficacy, and provide prognostic information.
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Abstract
Knowledge of the nature, prognosis, and ways to treat brain lesions in neonatal infants has increased remarkably. Neonatal hypoxic-ischaemic encephalopathy (HIE) in term infants, mirrors a progressive cascade of excito-oxidative events that unfold in the brain after an asphyxial insult. In the laboratory, this cascade can be blocked to protect brain tissue through the process of neuroprotection. However, proof of a clinical effect was lacking until the publication of three positive randomised controlled trials of moderate hypothermia for term infants with HIE. These results have greatly improved treatment prospects for babies with asphyxia and altered understanding of the theory of neuroprotection. The studies show that moderate hypothermia within 6 h of asphyxia improves survival without cerebral palsy or other disability by about 40% and reduces death or neurological disability by nearly 30%. The search is on to discover adjuvant treatments that can further enhance the effects of hypothermia.
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Wachtel EV, Hendricks-Muñoz KD. Current management of the infant who presents with neonatal encephalopathy. Curr Probl Pediatr Adolesc Health Care 2011; 41:132-53. [PMID: 21458747 DOI: 10.1016/j.cppeds.2010.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neonatal encephalopathy after perinatal hypoxic-ischemic insult is a major contributor to global child mortality and morbidity. Brain injury in term infants in response to hypoxic-ischemic insult is a complex process evolving over hours to days, which provides a unique window of opportunity for neuroprotective treatment interventions. Advances in neuroimaging, brain monitoring techniques, and tissue biomarkers have improved the ability to diagnose, monitor, and care for newborn infants with neonatal encephalopathy as well as predict their outcome. However, challenges remain in early identification of infants at risk for neonatal encephalopathy, determination of timing and extent of hypoxic-ischemic brain injury, as well as optimal management and treatment duration. Therapeutic hypothermia is the most promising neuroprotective intervention to date for infants with moderate to severe neonatal encephalopathy after perinatal asphyxia and has currently been incorporated in many neonatal intensive care units in developed countries. However, only 1 in 6 babies with encephalopathy will benefit from hypothermia therapy; many infants still develop significant adverse outcomes. To enhance the outcome, specific diagnostic predictors are needed to identify patients likely to benefit from hypothermia treatment. Studies are needed to determine the efficacy of combined therapeutic strategies with hypothermia therapy to achieve maximal neuroprotective effect. This review focuses on important concepts in the pathophysiology, diagnosis, and management of infants with neonatal encephalopathy due to perinatal asphyxia, including an overview of recently introduced novel therapies.
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Affiliation(s)
- Elena V Wachtel
- Department of Pediatrics, Division of Neonatology, New York University School of Medicine, New York, NY, USA
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14
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Hoque N, Chakkarapani E, Liu X, Thoresen M. A comparison of cooling methods used in therapeutic hypothermia for perinatal asphyxia. Pediatrics 2010; 126:e124-30. [PMID: 20530071 DOI: 10.1542/peds.2009-2995] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The objective of this study was to compare cooling methods during therapeutic hypothermia (TH) for moderate or severe perinatal asphyxia with regard to temperature and hemodynamic stability. METHODS A total of 73 newborns received TH in our center between 1999 and 2009 by 4 methods: (1) selective head cooling with mild systemic hypothermia by using cap (SHC; n = 20); (2) whole-body cooling with mattress manually controlled (WBCmc; n = 23); (3) whole-body cooling with body wrap servo-controlled (WBCsc; n = 28); and (4) whole-body cooling with water-filled gloves (n = 2). Target rectal temperatures (Trec) were 34.5 +/- 0.5 degrees C (SHC) and 33.5 +/- 0.5 degrees C (WBC). Trec, mean arterial blood pressure, and heart rate were collected from retrospective chart review. RESULTS Groups had similar baseline characteristics and condition at birth. Trec was within target temperature +/-0.5 degree C for 97% of the time in infants with WBCsc, 81% in infants with WBCmc, 76% in infants with SHC, and 74% in infants who were cooled with gloves. Mean overshoot was 0.3 degree C for WBCsc, 1.3 degrees C for WBCmc, and 0.8 degree C for SHC groups. There was no difference in mean arterial blood pressure or mean heart between groups during the maintenance of cooling. In infants who were rewarmed at similar speed, there was greater variation in Trec in the SHC compared with the WBCsc group. CONCLUSIONS Manually controlled cooling systems are associated with greater variability in Trec compared with servo-controlled systems. A manual mattress often causes initial overcooling. It is unknown whether large variation in temperature adversely affects the neuroprotection of TH.
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Affiliation(s)
- Nicholas Hoque
- Child Health, School of Clinical Sciences, University of Bristol, St Michael's Hospital, Bristol, Avon, UK
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15
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Metabolomic analyses of plasma reveals new insights into asphyxia and resuscitation in pigs. PLoS One 2010; 5:e9606. [PMID: 20231903 PMCID: PMC2834759 DOI: 10.1371/journal.pone.0009606] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 02/12/2010] [Indexed: 02/06/2023] Open
Abstract
Background Currently, a limited range of biochemical tests for hypoxia are in clinical use. Early diagnostic and functional biomarkers that mirror cellular metabolism and recovery during resuscitation are lacking. We hypothesized that the quantification of metabolites after hypoxia and resuscitation would enable the detection of markers of hypoxia as well as markers enabling the monitoring and evaluation of resuscitation strategies. Methods and Findings Hypoxemia of different durations was induced in newborn piglets before randomization for resuscitation with 21% or 100% oxygen for 15 min or prolonged hyperoxia. Metabolites were measured in plasma taken before and after hypoxia as well as after resuscitation. Lactate, pH and base deficit did not correlate with the duration of hypoxia. In contrast to these, we detected the ratios of alanine to branched chained amino acids (Ala/BCAA; R2.adj = 0.58, q-value<0.001) and of glycine to BCAA (Gly/BCAA; R2.adj = 0.45, q-value<0.005), which were highly correlated with the duration of hypoxia. Combinations of metabolites and ratios increased the correlation to R2adjust = 0.92. Reoxygenation with 100% oxygen delayed cellular metabolic recovery. Reoxygenation with different concentrations of oxygen reduced lactate levels to a similar extent. In contrast, metabolites of the Krebs cycle (which is directly linked to mitochondrial function) including alpha keto-glutarate, succinate and fumarate were significantly reduced at different rates depending on the resuscitation, showing a delay in recovery in the 100% reoxygenation groups. Additional metabolites showing different responses to reoxygenation include oxysterols and acylcarnitines (n = 8–11, q<0.001). Conclusions This study provides a novel strategy and set of biomarkers. It provides biochemical in vivo data that resuscitation with 100% oxygen delays cellular recovery. In addition, the oxysterol increase raises concerns about the safety of 100% O2 resuscitation. Our biomarkers can be used in a broad clinical setting for evaluation or the prediction of damage in conditions associated with low tissue oxygenation in both infancy and adulthood. These findings have to be validated in human trials.
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Abstract
Neonatal brain injury is an important cause of death and disability, with pathways of oxidant stress, inflammation, and excitotoxicity that lead to damage that progresses over a long period of time. Therapies have classically targeted individual pathways during early phases of injury, but more recent therapies such as growth factors may also enhance cell proliferation, differentiation, and migration over time. More recent evidence suggests combined therapy may optimize repair, decreasing cell injury while increasing newly born cells.
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Affiliation(s)
| | - Donna M. Ferriero
- Department of Pediatrics; University of California, San Francisco (FFG, DMF)
- Department of Neurology; University of California, San Francisco (DMF)
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Gonzalez FF, Ferriero DM. Therapeutics for neonatal brain injury. Pharmacol Ther 2008; 120:43-53. [PMID: 18718848 DOI: 10.1016/j.pharmthera.2008.07.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 07/08/2008] [Indexed: 01/19/2023]
Abstract
Neonatal brain injury is an important cause of death and neurodevelopmental delay. Multiple pathways of oxidant stress, inflammation, and excitotoxicity lead to both early and late phases of cell damage and death. Therapies targeting these different pathways have shown potential in protecting the brain from ongoing injury. More recent therapies, such as growth factors, have demonstrated an ability to increase cell proliferation and repair over longer periods of time. Even though hypothermia, which decreases cerebral metabolism and possibly affects other mechanisms, may show some benefit in particular cases, no widely effective therapeutic interventions for human neonates exist. In this review, we summarize recent findings in neuroprotection and neurogenesis for the immature brain, including combination therapy to optimize repair.
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Affiliation(s)
- Fernando F Gonzalez
- Department of Pediatrics, University of California-San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143, USA
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Degos V, Loron G, Mantz J, Gressens P. Neuroprotective Strategies for the Neonatal Brain. Anesth Analg 2008; 106:1670-80. [DOI: 10.1213/ane.0b013e3181733f6f] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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19
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Northington FJ. Brief update on animal models of hypoxic-ischemic encephalopathy and neonatal stroke. ILAR J 2006; 47:32-8. [PMID: 16391429 DOI: 10.1093/ilar.47.1.32] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The discovery of safe and effective therapies for perinatal hypoxia ischemia (HI) and stroke remains an unmet goal of neonatal-perinatal medicine. Because of the many developmental and functional differences between the neonatal brain and the adult brain, the ability to extrapolate adult data to the neonatal condition is very limited. For this reason, it is incumbent on scientists in the field of neonatal brain injury to address the questions of therapeutic efficacy of an array of potential therapies in a developmentally appropriate model. Toward that end, a number of new models of neonatal HI and stroke have been introduced recently. Additionally, some of the established models have been adapted to different species and different ages, giving scientists a greater choice of models for the study of neonatal HI and stroke. Many of these models are now also being used for functional and behavioral testing, an absolute necessity for preclinical therapeutic trials. This review focuses primarily on the newly developed models, recent adaptations to established models, and the studies of functional outcome that have been published since 2000.
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Affiliation(s)
- Frances J Northington
- Department of Pediatrics, Eudowood Neonatal Pulmonary Division, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Kanagawa T, Fukuda H, Tsubouchi H, Komoto Y, Hayashi S, Fukui O, Shimoya K, Murata Y. A decrease of cell proliferation by hypothermia in the hippocampus of the neonatal rat. Brain Res 2006; 1111:36-40. [PMID: 16904084 DOI: 10.1016/j.brainres.2006.06.112] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 06/19/2006] [Accepted: 06/29/2006] [Indexed: 11/21/2022]
Abstract
Hypothermia is a potential therapy for cerebral hypoxic ischemic injury of not only adults but also neonates. However, the side effects of hypothermia in the developing brain, where a massive amount of neurogenesis occurs, remain unclear. We investigated the proliferation of neural progenitor cells by systemic application of the thymidine analog 5-bromodeoxyuridine (BrdU) in neonatal rats in a severe hypothermic environment. The rat pups were divided into two groups, a hypothermia group (30 degrees C: n=10) and a normothermia group (37 degrees C: n=10). After the pups were placed for 21 h in each environment, 100 mg/kg/day of BrdU was injected intraperitoneally to label dividing cells, and then the pups were sacrificed at 24 h. We examined the number of BrdU-labeled cells in the subventricular zone of the periventricle and the subgranular zone of the dentate gyrus. In the hypothermic environment, BrdU-labeled cells significantly decreased in number in the dentate gyrus, but not in the periventricular region. Thus, the severe hypothermic environment induced a decrease of neurogenesis in the neonatal rat. These observations are noteworthy regarding clinical hypothermia therapy following cerebral hypoxic ischemic injury during the perinatal period.
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Affiliation(s)
- Takeshi Kanagawa
- Department of Obstetrics and Gynecology, Osaka University, Faculty of Medicine, 2-2 Yamadaoaka, Suita, Osaka 565-0871, Japan.
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Vento M, Escrig R, Saenz P, Izquierdo I, Sastre J, Viña J. Does oxygen concentration used for resuscitation influence outcome of asphyxiated newly born infants treated with hypothermia? Pediatrics 2006; 117:2326-8; author reply 2328. [PMID: 16740888 DOI: 10.1542/peds.2005-2804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Rutherford MA, Azzopardi D, Whitelaw A, Cowan F, Renowden S, Edwards AD, Thoresen M. Mild hypothermia and the distribution of cerebral lesions in neonates with hypoxic-ischemic encephalopathy. Pediatrics 2005; 116:1001-6. [PMID: 16199715 DOI: 10.1542/peds.2005-0328] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hypothermia induced by whole-body cooling (WBC) and selective head cooling (SHC) both reduce brain injury after hypoxia-ischemia in newborn animals, but it is not known how these treatments affect the incidence or pattern of brain injury in human newborns. To assess this, 14 term infants with hypoxic-ischemic encephalopathy (HIE) treated with SHC, 20 infants with HIE treated with WBC, and 52 noncooled infants with HIE of similar severity were studied with magnetic resonance imaging in the neonatal period. Infants fulfilling strict criteria for HIE were recruited into the study after assessment of an amplitude-integrated electroencephalography (aEEG). Cooling was commenced within 6 hours of birth and continued for 48 to 72 hours. Hypothermia was not associated with unexpected or unusual lesions, and the prevalence of intracranial hemorrhage was similar in all 3 groups. Both modes of hypothermia were associated with a decrease in basal ganglia and thalamic lesions, which are predictive of abnormal outcome. This decrease was significant in infants with a moderate aEEG finding but not in those with a severe aEEG finding. A decrease in the incidence of severe cortical lesions was seen in the infants treated with SHC.
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Affiliation(s)
- Mary A Rutherford
- Imaging Sciences Department, Imperial College, Hammersmith Hospital, London, United Kingdom.
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Abstract
We review the current state-of-the-art of diffuse optical imaging, which is an emerging technique for functional imaging of biological tissue. It involves generating images using measurements of visible or near-infrared light scattered across large (greater than several centimetres) thicknesses of tissue. We discuss recent advances in experimental methods and instrumentation, and examine new theoretical techniques applied to modelling and image reconstruction. We review recent work on in vivo applications including imaging the breast and brain, and examine future challenges.
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Affiliation(s)
- A P Gibson
- Department of Medical Physics and Bioengineering, University College London, UK
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Tooley JR, Eagle RC, Satas S, Thoresen M. Significant head cooling can be achieved while maintaining normothermia in the newborn piglet. Arch Dis Child Fetal Neonatal Ed 2005; 90:F262-6. [PMID: 15846020 PMCID: PMC1721873 DOI: 10.1136/adc.2003.044305] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Hypothermia has been shown to be neuroprotective in animal models of hypoxia-ischaemia. It is currently being evaluated as a potentially therapeutic option in the management of neonatal hypoxic-ischaemic encephalopathy. However, significant hypothermia has adverse systemic effects. It has also recently been found that the stress of being cold can abolish the neuroprotective effects of hypothermia. It is hypothesised that selective head cooling (SHC) while maintaining normal core temperature would enable local hypothermic neuroprotection while limiting the stress and side effects of hypothermia. OBJECTIVE To determine whether it is possible to induce moderate cerebral hypothermia in the deep brain of the piglet while maintaining the body at normothermia (39 degrees C). METHODS Six piglets (<48 hours old) were anaesthetised, and temperature probes inserted into the brain. Temperature was measured at different depths from the brain surface (21 mm (T(deep brain)) to 7 mm (T(superficial brain))). After a 45 minute global hypoxic-ischaemic insult, each piglet was head cooled for seven hours using a cap circulated with cold water (median 8.9 degrees C (interquartile range 7.5-14)) wrapped around the head. Radiant overhead heating was used to warm the body during cooling. RESULTS During SHC it was possible to cool the brain while maintaining a normal core temperature. The mean (SD) T(deep brain) during the seven hour cooling period was 31.1 (4.9) degrees C while T(rectal) remained stable at 38.8 (0.4) degrees C. The mean T(rectal)-T(deep brain) difference throughout the cooling period was 9.8 (6.1) degrees C. The mean T(skin) required was 40.8 (1.1) degrees C. There was no evidence of skin damage secondary to these skin temperatures. During cooling only one piglet shivered. CONCLUSIONS It is possible to maintain systemic normothermia in piglets while significantly cooling the deeper structures of the brain. This method of cooling may further limit the side effects associated with systemic hypothermia and be feasible for premature infants.
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Affiliation(s)
- J R Tooley
- Department of Child Health, St Michael's Hospital, Southwell Street, Bristol BS2 8EG, UK
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25
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Abstract
This chapter aims to provide an overview of aspects of risk management as they might be applied to the practice of resuscitation of the newborn using general principles of risk management and specific standards where they apply. Section 1 considers the matter of hazard and risk and how they may be classified. Figures are presented to provide a clinical perspective on resuscitation with a discussion on the hierarchy of clinical risks operating upon the baby. Section 2 centres on a discussion of those aspects that operate to modify the risks to the baby during a resuscitation, including environmental considerations (location, clinical setting and equipment); staffing issues (establishment, competency, induction and training) and logistics (process, communication and documentation). Section 3 debates the place of cord gases in the context of the diagnosis of perinatal hypoxaemia.
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Affiliation(s)
- John Madar
- Consultant Neonatologist & Clinical Director, SW Peninsula Neonatal Network, Derriford Hospital, Level 5, Plymouth, Devon, England PL6 8DH, United Kingdom.
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Celtik C, Acunaş B, Oner N, Pala O. Neuron-specific enolase as a marker of the severity and outcome of hypoxic ischemic encephalopathy. Brain Dev 2004; 26:398-402. [PMID: 15275704 DOI: 10.1016/j.braindev.2003.12.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2003] [Revised: 12/24/2003] [Accepted: 12/24/2003] [Indexed: 10/26/2022]
Abstract
The aim of this study was to evaluate serum concentrations of neuron-specific enolase (NSE) as a marker of the severity of hypoxic ischemic encephalopathy (HIE) and to elucidate the relation among the concentrations of NSE, grade of HIE and short-term outcome. Forty-three asphyxiated full-term newborn infants who developed symptoms and signs of HIE (Group 1) and 29 full-term newborn infants with meconium-stained amniotic fluid but with normal physical examination (Group 2) were studied with serial neurological examination, Denver developmental screening test (DDST), electroencephalogram and computerized cerebral tomography (CT) for neurological follow-up. Thirty healthy infants were selected as the control group. In the patient groups, two blood samples were taken to measure NSE levels, one between 4 and 48 h and the other 5-7 days after birth. Serum NSE levels were significantly higher in infants with HIE compared to those infants in Group 2 and control group. The mean serum concentrations of the second samples decreased in all groups studied but they were significantly higher in Group 1 compared to those in Group 2. Serum NSE concentrations of initial samples were significantly higher in patients with stage III HIE than in those with stages II and I. The sensitivity and specificity values of serum NSE as a predictor of HIE of moderate or severe degree (cut-off value 40.0 microg/l) were 79 and 70%, respectively, and as a predictor of poor outcome (cut-off value 45.4 microg/l) were calculated as 84 and 70%, respectively. The predictive capacity of serum NSE concentrations for poor outcome seems to be better than predicting HIE of moderate or severe degree. However, earlier and/or CSF samples may be required to establish serum NSE as an early marker for the application of neuroprotective strategies.
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Affiliation(s)
- Coşkun Celtik
- Department of Pediatrics, Trakya University Faculty of Medicine, 22030 Edrine, Turkey.
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Takei Y, Nishikawa Y, Tachibana M, Takami T, Miyajima T, Hoshika A, Takashima S. Hypothermia during kainic acid-induced seizures reduces hippocampal lesions and cerebral nitric oxide production in immature rabbits. Brain Dev 2004; 26:176-83. [PMID: 15030906 DOI: 10.1016/s0387-7604(03)00123-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2003] [Revised: 06/10/2003] [Accepted: 06/16/2003] [Indexed: 10/27/2022]
Abstract
We investigated (1) whether cerebral hypothermia during kainic acid (KA)-induced seizures was neuroprotective; and (2) whether nitric oxide (NO) production in the brain during seizures was altered by cerebral hypothermia in immature rabbits. Twelve female rabbits, aged 2 weeks, were anesthetized, paralyzed and mechanically ventilated. We continuously measured NO production in the brain by NO-selective electrode, cortical electroencephalogram (EEG), regional cerebral blood flow (rCBF) by laser Doppler flowmetry, rectal and cerebral temperatures and mean arterial blood pressure (MABP) during KA (12 mg/kg, i.v.)-induced seizures in the hypothermic group (n = 6; rectal temperature, 33 degrees C), and in the normothermic group (n = 6; rectal temperature, 37 degrees C). The normothermic group showed a gradual increase in NO generation in the brain, which was significantly inhibited in the hypothermic group. There were no significant differences in the increases in rCBF, MABP, arterial blood gases, blood glucose, or EEG abnormalities between the two groups. Neuronal damages in the hippocampus (CA3) were significantly lower in hypothermia than in normothermia. These results suggest that hypothermia attenuates NO production during drug-induced seizures and decreases hippocampal brain lesions in the immature rabbit brain. These results may help to explain the neuroprotective effects of hypothermia.
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Affiliation(s)
- Yukito Takei
- Department of Pediatrics, Tokyo Medical University, Tokyo, Japan.
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29
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Fugelseth D, Satas S, Steen PA, Thoresen M. Cardiac output, pulmonary artery pressure, and patent ductus arteriosus during therapeutic cooling after global hypoxia-ischaemia. Arch Dis Child Fetal Neonatal Ed 2003; 88:F223-8. [PMID: 12719397 PMCID: PMC2291510 DOI: 10.1136/fn.88.3.f223] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess by Doppler echocardiography the effects of 24 hours of whole body mild hypothermia compared with normothermia on cardiac output (CO), pulmonary artery pressure (PAP), and the presence of a persistent ductus arteriosus (PDA) after a global hypoxic-ischaemic insult in unsedated newborn animals. DESIGN Thirty five pigs (mean (SD) age 26.6 (12.1) hours and weight 1.6 (0.3) kg) were anaesthetised with halothane, mechanically ventilated, and subjected to a 45 minute global hypoxic-ischaemic insult. At the end of hypoxia, halothane was stopped; the pigs were randomised to either normathermia (39 degrees C) or hypothermia (35 degrees C) for 24 hours. Rewarming was carried out for 24-30 hours followed by 42 hours of normothermia. Unanaesthetised pigs were examined with a VingMed CFM 750 ultrasound scanner before and 3, 24, 30, and 48 hours after the hypoxic-ischaemic insult. Aortic valve diameter, forward peak flow velocities across the four valves, and the occurrence of a PDA were measured. Tricuspid regurgitation (TR) velocity was used to estimate the PAP. Stroke volume was calculated from the aortic flow. RESULTS Twelve animals (seven normothermic, five hypothermic) had a PDA on one or more examinations, which showed no association with cooling or severity of insult. There were no differences in stroke volume or TR velocity between the hypothermic and normothermic animals at any time point after the insult. CO was, however, 45% lower at the end of cooling in the subgroup of hypothermic pigs that had received a severe insult compared with the pigs with mild and moderate insults. CO and TR velocity were transiently increased three hours after the insult: 0.38 (0.08) v 0.42 (0.08) litres/min/kg (p = 0.007) for CO; 3.0 (0.42) v 3.4 (0.43) m/s (p < 0.0001) for TR velocity (values are mean (SD)). CONCLUSIONS The introduction of mild hypothermia while the pigs were unsedated did not affect the incidence of PDA nor did it lead to any changes in MABP or PAP. Stroke volume was also unaffected by temperature, but hypothermic piglets subjected to a severe hypoxic-ischaemic insult had reduced CO because the heart rate was lower. Global hypoxia-ischaemia leads to similar transient increases in CO and estimated PAP in unsedated normothermic and hypothermic pigs. There were no signs of metabolic compromise in any subgroup, suggesting that 24 hours of mild hypothermia had no adverse cardiovascular effect.
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Affiliation(s)
- D Fugelseth
- Institute for Experimental Medical Research, Ullevål University Hospital, Oslo, Norway
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Hüppi PS. Advances in postnatal neuroimaging: relevance to pathogenesis and treatment of brain injury. Clin Perinatol 2002; 29:827-56. [PMID: 12516748 DOI: 10.1016/s0095-5108(02)00049-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The human brain is susceptible to a wide variety of insults. The permanent residua of these abnormalities are represented in dysfunction of one or more areas of neurodevelopment. A full understanding of normal brain development, mechanisms of brain injury, and consequences for subsequent brain development is required to determine which infants are at risk for neurodevelopmental handicap, and to monitor the effects of new treatments and management regimens designed to prevent these disabilities. Advanced magnetic resonance techniques, such as quantitative morphometric magnetic resonance techniques, diffusion-weighted magnetic resonance techniques, and magnetic resonance spectroscopy applied to the study of early human brain development have given us a better understanding of the pathophysiologic mechanisms of brain injury and its effects on subsequent brain development. Magnetic resonance imaging has provided an invaluable tool for the study of the fetal and newborn brain in vivo.
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Affiliation(s)
- Petra S Hüppi
- Child Development Unit, Department of Pediatrics, Childrens Hospital, 6 rue Willy-Donze, University of Geneva, 1211 Geneva, Switzerland.
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Leonard SE, Kirby R. The role of glutamate, calcium and magnesium in secondary brain injury. J Vet Emerg Crit Care (San Antonio) 2002. [DOI: 10.1046/j.1534-6935.2002.00003.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
Neonatal stroke occurs in approximately 1 in 4,000 to 1 in 10,000 newborns, and more than 80% involve the vascular territory supplied by the middle cerebral artery. Neonatal stroke is associated with many acquired and genetic prothrombotic factors, and follow-up studies indicate that as many as two thirds of neonates develop neurologic deficits. In the past two decades unilateral carotid occlusion with 8% hypoxia has been used to study focal and global ischemia in the newborn, and recently a filament model of middle cerebral artery occlusion has been developed. This review describes the results of studies in these two newborn models covering aspects of the injury cascade that occurs after focal ischemia. A likely requirement is that therapeutic efforts be directed less at using thrombolytic therapy and more toward treatment of events associated with reperfusion injury, the inflammatory cascade, and apoptosis. Additional areas of research that have received attention in the past year include inhibition of nitric oxide and free-radical formation, use of iron chelating agents, the potential role of hypoxia-inducible factors and mediators of caspase activity, use of growth factors, hypothermia, and administration of magnesium sulfate.
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Affiliation(s)
- S Ashwal
- Department of Pediatrics, Division of Child Neurology, Loma Linda University School of Medicine, Loma Linda, California 12350, USA.
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Okubo K, Itoh S, Isobe K, Kusaka T, Nagano K, Kondo M, Onishi S. Cerebral metabolism and regional cerebral blood flow during moderate systemic cooling in newborn piglets. Pediatr Int 2001; 43:496-501. [PMID: 11737712 DOI: 10.1046/j.1442-200x.2001.01444.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Clinical trials of hypothermic therapy in asphyxiated infants have started recently. However, clinical studies have been delayed by the difficulty in selecting infants with a bad neurological prognosis and by the concern regarding adverse effects of hypothermia. The purpose of this study is to examine the effects of systemic cooling on cerebral metabolism (CMR) and the regional cerebral blood flow (rCBF) in newborn piglets. METHODS The rCBF in the seven parts of the brain were measured with colored microspheres. The blood samples for the measurement of cerebral oxygen consumption (CMRO2) and cerebral glucose consumption (CMRglc) was collected from the umbilical artery and the superior sagittal sinus. RESULTS Reductions of cerebral cortex temperature to 32 degrees C decreased blood flow in all brain regions. In particular, blood flow in the brainstem decreased more significantly than in any other region. The total cerebral blood flow (CBF), CMRO2 and CMRglc, respectively, decreased to 32.3+/-3.9 mL/100 g per min, 2.8+/-1.0 mLO2/100 g per min and 22+/-12 mmol/100 g per min at 32 degrees C (41, 53 and 46% of the initial value). The CBF decreased in parallel with CMRO2 and CMRglc down to 35 degrees C, but CBF decreased to a greater extent than CMRO2 and CMRglc at below 35 degrees C. CONCLUSIONS The indication of hypothermic therapy and the degree of cooling have to be performed very carefully. Systemic cooling is especially dangerous for the total asphyxiated infants who might have damage to the brainstem because the blood flow in the brainstem has significantly decreased during hypothermia.
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Affiliation(s)
- K Okubo
- Department of Pediatrics, Kagawa Medical University, Kitagun, Japan.
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Thoresen M, Satas S, Løberg EM, Whitelaw A, Acolet D, Lindgren C, Penrice J, Robertson N, Haug E, Steen PA. Twenty-four hours of mild hypothermia in unsedated newborn pigs starting after a severe global hypoxic-ischemic insult is not neuroprotective. Pediatr Res 2001; 50:405-11. [PMID: 11518829 DOI: 10.1203/00006450-200109000-00017] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Three to 12 h of mild hypothermia (HT) starting after hypoxia-ischemia is neuroprotective in piglets that are anesthetized during HT. Newborn infants suffering from neonatal encephalopathy often ventilate spontaneously and are not necessarily sedated. We aimed to test whether mild posthypoxic HT lasting 24 h was neuroprotective if the animals were not sedated. Thirty-nine piglets (median weight 1.6 kg, range 0.8-2.2 kg; median age 24 h, range 7-48 h) were anesthetized and ventilated and subjected to a 45-min hypoxic (FiO(2) approximately 6%) global insult (n = 36) or sham hypoxia (n = 3). On reoxygenation, 18 were maintained normothermic (NT, 39.0 degrees C) for 72 h, and 21 were cooled from 39 (NT) to 35 degrees C (HT) for the first 24 h before NT was resumed (18 experimental, three sham hypoxia). Cardiovascular parameters and intermittent EEG were documented throughout. The brain was perfusion fixed for neuropathology and five main areas examined using light microscopy. The insult severity (duration in minutes of EEG amplitude < 7 microV) was similar in the NT and HT groups, mean +/- SD (28 +/- 7.2 versus 27 +/- 8.6 min), as was the mean FiO(2) (5.9 +/- 0.7 versus 5.8 +/- 0.8%) during the insult. Six NT and seven HT piglets developed posthypoxic seizures that lasted 29 and 30% of the time, respectively. The distribution and degree of injury (0.0-4.0, normal-maximal damage) within the brain (hippocampus, cortex/white matter, cerebellum, basal ganglia, thalamus) were similar in the NT and HT groups (overall score, mean +/- SD, 2.3 +/- 1.5 versus 2.4 +/- 1.3) as was the EEG background amplitude at 3 h (13 +/- 3.5 versus 10 +/- 3.3 microV). The HT animals shivered and were more active. The sham control group (n = 3) shivered but had normal physiology and neuropathology. Plasma cortisol was significantly higher in the HT group during the HT period, 766 +/- 277 versus 244 +/- 144 microM at 24 h. Mild postinsult HT for 24 h was not neuroprotective in unsedated piglets and did not reduce the number of animals that developed posthypoxic seizures. Cortisol reached 3 times the NT value at the end of HT. We speculate that the stress of shivering and feeling cold interfered with the previously shown neuroprotective effect of HT. Research on the appropriateness of sedation during clinical HT is urgent.
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Affiliation(s)
- M Thoresen
- Department of Experimental Medicine, Ullevål Hospital, Oslo, Norway.
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35
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Han JW, Van Leeuwen GM, Mizushina S, Van de Kamer JB, Maruyama K, Sugiura T, Azzopardi DV, Edwards AD. Monitoring of deep brain temperature in infants using multi-frequency microwave radiometry and thermal modelling. Phys Med Biol 2001; 46:1885-903. [PMID: 11474932 DOI: 10.1088/0031-9155/46/7/311] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study we present a design for a multi-frequency microwave radiometer aimed at prolonged monitoring of deep brain temperature in newborn infants and suitable for use during hypothermic neural rescue therapy. We identify appropriate hardware to measure brightness temperature and evaluate the accuracy of the measurements. We describe a method to estimate the tissue temperature distribution from measured brightness temperatures which uses the results of numerical simulations of the tissue temperature as well as the propagation of the microwaves in a realistic detailed three-dimensional infant head model. The temperature retrieval method is then used to evaluate how the statistical fluctuations in the measured brightness temperatures limit the confidence interval for the estimated temperature: for an 18 degrees C temperature differential between cooled surface and deep brain we found a standard error in the estimated central brain temperature of 0.75 degrees C. Evaluation of the systematic errors arising from inaccuracies in model parameters showed that realistic deviations in tissue parameters have little impact compared to uncertainty in the thickness of the bolus between the receiving antenna and the infant's head or in the skull thickness. This highlights the need to pay particular attention to these latter parameters in future practical implementation of the technique.
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Affiliation(s)
- J W Han
- Department of Imaging, Imperial College School of Medicine, London, UK.
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36
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Hüppi PS, Amato M. Advanced magnetic resonance imaging techniques in perinatal brain injury. BIOLOGY OF THE NEONATE 2001; 80:7-14. [PMID: 11474142 DOI: 10.1159/000047112] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Despite marked improvements in perinatal practice, perinatal brain injury remains one of the most common complications causing chronic handicapping conditions. Experimental advances have elucidated many of the cellular and vascular mechanisms of perinatal brain damage showing a correlation between the nature of the injury and the maturation of the brain. New diagnostic tools, such as quantitative three-dimensional magnetic resonance (MR) imaging, diffusion-weighted MR imaging and proton MR spectroscopy, are presented in this review article that allow to assess brain development, detect early brain injury and monitor effects of perinatal brain injury on subsequent brain development and brain plasticity. These techniques will guide future therapeutic interventions aimed at minimizing irreversible perinatal brain injury.
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Affiliation(s)
- P S Hüppi
- Department of Paediatrics, Children's Hospital, University of Geneva, Switzerland.
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37
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Abstract
Acute heart failure is unusual in the pediatric population, but in many situations it justifies aggressive therapy. For example, children with lymphocytic myocarditis have an overall survival rate of nearly 90%, with complete myocardial recovery for the majority. Pharmacologic agents traditionally have been the mainstay of medical therapy for acute heart failure, but, in recent years, there has been increasing interest in using measures that reduce the myocardial workload. This article highlights nonpharmacologic approaches to the management of severe heart failure in the critically ill child. It also concentrates on physiologic approaches that address the balance between oxygen demand and delivery; the manipulation of cardiopulmonary interactions to optimize ventricular function; and the use of mechanical circulatory support as a method of achieving ultimate myocardial rest.
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Affiliation(s)
- L Shekerdemian
- Cardiac Intensive Care Unit, Great Ormond Street Hospital, London, UK.
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38
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Scher M. Perinatal asphyxia: timing and mechanisms of injury in neonatal encephalopathy. Curr Neurol Neurosci Rep 2001; 1:175-84. [PMID: 11898514 DOI: 10.1007/s11910-001-0014-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article summarizes the recent medical literature regarding perinatal asphyxia with respect to timing and mechanisms of injury for neonates who were clinically diagnosed with an encephalopathy in the newborn period. Multiple mechanisms of injury are reviewed, including genetic vulnerability, acquired inflammatory responses, and clotting defects that can lead to ischemic-induced brain damage. Before effective treatments for fetal and neonatal brain disorders can be developed, accurate and timely diagnoses of fetal or neonatal brain injury must be achieved. Specific subsets of children can then benefit from neuroprotective strategies that can target the specific developmental aspects of brain adaptation or plasticity relative to the specific etiology and timing of injury after asphyxia.
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Affiliation(s)
- M Scher
- Division of Pediatrics and Neurology, Rainbow Babies and Children's Hospital, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-6090, USA.
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