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Toxoplasma gondii infection in goats: serological, pathological, and clinical monitoring during gestation. Parasitol Res 2022; 121:3147-3153. [PMID: 36040630 PMCID: PMC9424794 DOI: 10.1007/s00436-022-07633-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/19/2022] [Indexed: 11/07/2022]
Abstract
This study aimed to evaluate Toxoplasma gondii infection in pregnant goats. The goats were divided into two groups: group one (G1) comprised of 31 pregnant goats naturally infected with T. gondii, and group two (G2) comprised of seven uninfected pregnant goats from a flock with a history of abortion due to toxoplasmosis. Serological investigation, ultrasonography, and clinical testing were performed on all goats during gestation. Serum samples from goats and their offspring (precolostral) were collected to evaluate the vertical transmission of T. gondii. Samples from placentas and aborted fetuses were also collected for molecular and histopathological analysis. Results showed that in G1, estrus recurrence occurred in 22.6% (7/31) of the goats, embryonic death in 3.3% (1/31), and abortion in 19.4% (6/31). An increase in anti-T. gondii antibodies was observed in G1 goats at day 150 of pregnancy. T. gondii DNA was detected in 42.8% (3/7) of aborted fetuses and was associated with histopathological lesions caused by this parasite. Moreover, toxoplasmosis in field conditions caused by genotype ToxoDB #1 in pregnant goats resulted in severe reproductive loss in the flock.
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2
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Cavarsan CF, Gorassini MA, Quinlan KA. Animal models of developmental motor disorders: parallels to human motor dysfunction in cerebral palsy. J Neurophysiol 2019; 122:1238-1253. [PMID: 31411933 PMCID: PMC6766736 DOI: 10.1152/jn.00233.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
Cerebral palsy (CP) is the most common motor disability in children. Much of the previous research on CP has focused on reducing the severity of brain injuries, whereas very few researchers have investigated the cause and amelioration of motor symptoms. This research focus has had an impact on the choice of animal models. Many of the commonly used animal models do not display a prominent CP-like motor phenotype. In general, rodent models show anatomically severe injuries in the central nervous system (CNS) in response to insults associated with CP, including hypoxia, ischemia, and neuroinflammation. Unfortunately, most rodent models do not display a prominent motor phenotype that includes the hallmarks of spasticity (muscle stiffness and hyperreflexia) and weakness. To study motor dysfunction related to developmental injuries, a larger animal model is needed, such as rabbit, pig, or nonhuman primate. In this work, we describe and compare various animal models of CP and their potential for translation to the human condition.
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Affiliation(s)
- Clarissa F Cavarsan
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island
| | - Monica A Gorassini
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Katharina A Quinlan
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island
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3
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Leonetti C, Back SA, Gallo V, Ishibashi N. Cortical Dysmaturation in Congenital Heart Disease. Trends Neurosci 2019; 42:192-204. [PMID: 30616953 PMCID: PMC6397700 DOI: 10.1016/j.tins.2018.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/28/2018] [Accepted: 12/11/2018] [Indexed: 01/09/2023]
Abstract
Congenital heart disease (CHD) is among the most common birth defects. Children with CHD frequently display long-term intellectual and behavioral disability. Emerging evidence indicates that cardiac anomalies lead to a reduction in cerebral oxygenation, which appears to profoundly impact on the maturation of cerebral regions responsible for higher-order cognitive functions. In this review we focus on the potential mechanisms by which dysregulation of cortical neuronal development during early life may lead to the significant cognitive impairments that commonly occur in children with CHD. Further understanding of the mechanisms underlying cortical dysmaturation due to CHD will be necessary to identify strategies for neonatal neuroprotection and for mitigating developmental delays in this patient population.
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Affiliation(s)
- Camille Leonetti
- Center for Neuroscience Research, Children's National Health System, Washington, DC 20010, USA; Children's National Heart Institute, Children's National Health System, Washington, DC 20010, USA
| | - Stephen A Back
- Department of Pediatrics, Oregon Health and Science University, Portland, OR 97239, USA; Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Health System, Washington, DC 20010, USA.
| | - Nobuyuki Ishibashi
- Center for Neuroscience Research, Children's National Health System, Washington, DC 20010, USA; Children's National Heart Institute, Children's National Health System, Washington, DC 20010, USA.
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4
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Lawrence KM, Hennessy-Strahs S, McGovern PE, Mejaddam AY, Rossidis AC, Baumgarten HD, Bansal E, Villeda M, Han J, Gou Z, Zhao S, Rychik J, Peranteau WH, Davey MG, Flake AW, Gaynor JW, Bartoli CR. Fetal hypoxemia causes abnormal myocardial development in a preterm ex utero fetal ovine model. JCI Insight 2018; 3:124338. [PMID: 30568044 DOI: 10.1172/jci.insight.124338] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023] Open
Abstract
In utero hypoxia is a major cause of neonatal morbidity and mortality and predisposes to adult cardiovascular disease. No therapies exist to correct fetal hypoxia. In a new ex utero fetal support system, we tested the hypothesis that hypoxemic support of the fetus impairs myocardial development, whereas normoxic support allows normal myocardial development. Preterm fetal lambs were connected via umbilical vessels to a low-resistance oxygenator and placed in a sterile-fluid environment. Control normoxic fetuses received normal fetal oxygenation, and hypoxemic fetuses received subphysiologic oxygenation. Fetuses with normal in utero development served as normal controls. Hypoxemic fetuses exhibited decreased maximum cardiac output in both ventricles, diastolic function, myocyte and myocyte nuclear size, and increased myocardial capillary density versus control normoxic fetuses. There were no differences between control normoxic fetuses in the fetal support system and normal in utero controls. Chronic fetal hypoxemia resulted in significant abnormalities in myocyte architecture and myocardial capillary density as well as systolic and diastolic cardiac function, whereas control fetuses showed no differences. This ex utero fetal support system has potential to become a significant research tool and novel therapy to correct fetal hypoxia.
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Affiliation(s)
- Kendall M Lawrence
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Samson Hennessy-Strahs
- Division of Cardiovascular Surgery, Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Patrick E McGovern
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Ali Y Mejaddam
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Avery C Rossidis
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Heron D Baumgarten
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Esha Bansal
- Division of Cardiovascular Surgery, Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maryann Villeda
- Division of Cardiovascular Surgery, Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jiancheng Han
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Zhongshan Gou
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Sheng Zhao
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Jack Rychik
- Division of Cardiology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - William H Peranteau
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Marcus G Davey
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - Alan W Flake
- Center for Fetal Research, Department of Surgery, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
| | - J William Gaynor
- Division of Pediatric Cardiothoracic Surgery, Department of Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Carlo R Bartoli
- Division of Cardiovascular Surgery, Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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5
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Garnier Y, Coumans ABC, Jensen A, Hasaart THM, Berger R. Infection-Related Perinatal Brain Injury: The Pathogenic Role of Impaired Fetal Cardiovascular Control. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/s1071-55760300150-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Tom H. M. Hasaart
- Department of Obstetrics and Gynecology, University of Bochum, Bochum, Germany; Department of obstetrics and Gynecology, University of Maastricht, Maastricht, The Netherlands
| | - Richard Berger
- Department of Obstetrics and Gynecology, University of Bochum, Bochum, Germany; Department of obstetrics and Gynecology, University of Maastricht, Maastricht, The Netherlands; Universitätsfrauenklinik Bochum, Knappschaftskrankenhaus, In der Schornau 23-25, 44982 Bochum
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6
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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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Matsuda Y, Umezaki H, Ogawa M, Ohwada M, Satoh S, Nakai A. Umbilical arterial pH in patients with cerebral palsy. Early Hum Dev 2014; 90:131-5. [PMID: 24485169 DOI: 10.1016/j.earlhumdev.2014.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/27/2013] [Accepted: 01/03/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Umbilical arterial pH (UApH) in severe cerebral palsy (CP) is not fully understood. AIMS This work aims to determine the relationship between fetal acidemia and clinical features of severe CP. STUDY DESIGN A retrospective study design is used. SUBJECTS A review was conducted unti1 April 2013 among 218 infants with CP diagnosed to be caused by antenatal and/or intrapartum conditions determined by the Japan Council for Quality Health Care. After excluding patients in whom the causes of CP were thought to be due to events after delivery, 168 infants born at over 34weeks of gestation that both Apgar score and UApH were measured were selected. OUTCOME MEASURES Severe fetal acidemia was defined as a pH of less than 7.0. RESULTS Six major factors were found to be associated with CP: placental abruption (A, n=42), traumatic delivery with an abnormal FHR pattern (B, n=29), an abnormal FHR pattern during labor (C, n=27), chorioamnionitis with an abnormal FHR pattern (D, n=17), an abnormal FHR pattern before labor (E, n=14), and cord prolapse (F, n=10). The UApH was less than 7.0 in 114 cases (67.9%) and more than 7.20 in 20 cases (11.9%). The UApH values were lowest in group A (median 6.7, 6.43-6.99) and highest in group E (7.18, 6.92-7.45). The distribution of the UApH values was significantly different in these groups. CONCLUSION Placental abruption was a factor most associated with low pH. Even among the infants with severe CP, over 10% of patients exhibited a non-acidemic status at birth.
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Affiliation(s)
- Yoshio Matsuda
- Department of Obstetrics and Gynecology, International University of Health and Welfare Hospital, 537-3 Iguchi, Nasushiobara, Tochigi 329-2763, Japan; Department of Obstetrics and Gynecology, Tokyo Women's Medical University, Kawada-cho, 8-1, Shinjuku-ku, Tokyo 162-8666, Japan.
| | - Hikaru Umezaki
- Department of Obstetrics and Gynecology, International University of Health and Welfare Hospital, 537-3 Iguchi, Nasushiobara, Tochigi 329-2763, Japan
| | - Masaki Ogawa
- Department of Obstetrics and Gynecology, Tokyo Women's Medical University, Kawada-cho, 8-1, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Michitaka Ohwada
- Department of Obstetrics and Gynecology, International University of Health and Welfare Hospital, 537-3 Iguchi, Nasushiobara, Tochigi 329-2763, Japan
| | - Shoji Satoh
- Maternal and Perinatal Care Center, Oita Prefectural Hospital, Bunyo 476, Oita 870-8511, Japan
| | - Akihito Nakai
- Tama-Nagayama Hospital, Nippon Medical School, 1-7-1 Nagayama, Tama-City, Tokyo 206-8512, Japan
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8
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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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9
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Castaño P, Fuertes M, Ferre I, Fernández M, Ferreras MDC, Moreno-Gonzalo J, González-Lanza C, Katzer F, Regidor-Cerrillo J, Ortega-Mora LM, Pérez V, Benavides J. Placental thrombosis in acute phase abortions during experimental Toxoplasma gondii infection in sheep. Vet Res 2014; 45:9. [PMID: 24475786 PMCID: PMC3931317 DOI: 10.1186/1297-9716-45-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 01/16/2014] [Indexed: 02/08/2023] Open
Abstract
After oral administration of ewes during mid gestation with 2000 freshly prepared sporulated oocysts of T. gondii isolate M4, abortions occurred between days 7 and 11 in 91.6% of pregnant and infected ewes. Afterwards, a further infection was carried out at late gestation in another group of sheep with 500 sporulated oocysts. Abortions happened again between days 9 and 11 post infection (pi) in 58.3% of the infected ewes. Classically, abortions in natural and experimental ovine toxoplasmosis usually occur one month after infection. Few experimental studies have reported the so-called acute phase abortions as early as 7 to 14 days after oral inoculation of oocysts, and pyrexia was proposed to be responsible for abortion, although the underline mechanism was not elucidated. In the present study, all placentas analysed from ewes suffering acute phase abortions showed infarcts and thrombosis in the caruncullar villi of the placentomes and ischemic lesions (periventricular leukomalacia) in the brain of some foetuses. The parasite was identified by PCR in samples from some placentomes of only one sheep, and no antigen was detected by immunohistochemical labelling. These findings suggest that the vascular lesions found in the placenta, and the consequent hypoxic damage to the foetus, could be associated to the occurrence of acute phase abortions. Although the pathogenesis of these lesions remains to be determined, the infectious dose or virulence of the isolate may play a role in their development.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Julio Benavides
- Departamento de Sanidad Animal, Instituto de Ganadería de Montaña (CSIC-ULE), Grulleros, 24346 León, Spain.
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10
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Back SA, Riddle A, Dean J, Hohimer AR. The instrumented fetal sheep as a model of cerebral white matter injury in the premature infant. Neurotherapeutics 2012; 9:359-70. [PMID: 22399133 PMCID: PMC3337024 DOI: 10.1007/s13311-012-0108-y] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Despite advances in neonatal intensive care, survivors of premature birth remain highly susceptible to unique patterns of developmental brain injury that manifest as cerebral palsy and cognitive-learning disabilities. The developing brain is particularly susceptible to cerebral white matter injury related to hypoxia-ischemia. Cerebral white matter development in fetal sheep shares many anatomical and physiological similarities with humans. Thus, the fetal sheep has provided unique experimental access to the complex pathophysiological processes that contribute to injury to the human brain during successive periods in development. Recent refinements have resulted in models that replicate major features of acute and chronic human cerebral injury and have provided access to complex clinically relevant studies of cerebral blood flow and neuroimaging that are not feasible in smaller laboratory animals. Here, we focus on emerging insights and methodologies from studies in fetal sheep that have begun to define cellular and vascular factors that contribute to white matter injury. Recent advances include spatially defined measurements of cerebral blood flow in utero, the definition of cellular maturational factors that define the topography of injury and the application of high-field magnetic resonance imaging to define novel neuroimaging signatures for specific types of chronic white matter injury. Despite the higher costs and technical challenges of instrumented preterm fetal sheep models, they provide powerful access to clinically relevant studies that provide a more integrated analysis of the spectrum of insults that appear to contribute to cerebral injury in human preterm infants.
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Affiliation(s)
- Stephen A Back
- Department of Pediatrics, Oregon Health Sciences University, Portland, OR 97239, USA.
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11
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Rees S, Harding R, Walker D. The biological basis of injury and neuroprotection in the fetal and neonatal brain. Int J Dev Neurosci 2011; 29:551-63. [PMID: 21527338 PMCID: PMC3168707 DOI: 10.1016/j.ijdevneu.2011.04.004] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 04/08/2011] [Indexed: 12/29/2022] Open
Abstract
A compromised intrauterine environment that delivers low levels of oxygen and/or nutrients, or is infected or inflammatory, can result in fetal brain injury, abnormal brain development and in cases of chronic compromise, intrauterine growth restriction. Preterm birth can also be associated with injury to the developing brain and affect the normal trajectory of brain growth. This review will focus on the effects that episodes of perinatal hypoxia (acute, chronic, associated with inflammation or as an antecedent of preterm birth) can have on the developing brain. In animal models of these conditions we have found that relatively brief (acute) periods of fetal hypoxemia can have significant effects on the fetal brain, for example death of susceptible neuronal populations (cerebellum, hippocampus, cortex) and cerebral white matter damage. Chronic placental insufficiency which includes fetal hypoxemia, nutrient restriction and altered endocrine status can result in fetal growth restriction and long-term deficits in neural connectivity in addition to altered postnatal function, for example in the auditory and visual systems. Maternal/fetal inflammation can result in fetal brain damage, particularly but not exclusively in the white matter; injury is more pronounced when associated with fetal hypoxemia. In the baboon, in which the normal trajectory of growth is affected by preterm birth, there is a direct correlation between a higher flux in oxygen saturation and a greater extent of neuropathological damage. Currently, the only established therapy for neonatal encephalopathy in full term neonates is moderate hypothermia although this only offers some protection to moderately but not severely affected brains. There is no accepted therapy for injured preterm brains. Consequently the search for more efficacious treatments continues; we discuss neuroprotective agents (erythropoietin, N-acetyl cysteine, melatonin, creatine, neurosteroids) which we have trialed in appropriate animal models. The possibility of combining hypothermia with such agents or growth factors is now being considered. A deeper understanding of causal pathways in brain injury is essential for the development of efficacious strategies for neuroprotection.
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Affiliation(s)
- Sandra Rees
- Department of Anatomy and Cell Biology, University of Melbourne, Vic. 3010, Australia.
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12
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Rey-Santano C, Mielgo VE, Gastiasoro E, Murgia X, Lafuente H, Ruiz-Del-Yerro E, Valls-I-Soler A, Hilario E, Alvarez FJ. Early Cerebral Hemodynamic, Metabolic, and Histological Changes in Hypoxic-Ischemic Fetal Lambs during Postnatal Life. Front Neurosci 2011; 5:111. [PMID: 21960958 PMCID: PMC3176408 DOI: 10.3389/fnins.2011.00111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 08/29/2011] [Indexed: 11/13/2022] Open
Abstract
The hemodynamic, metabolic, and biochemical changes produced during the transition from fetal to neonatal life may be aggravated if an episode of asphyxia occurs during fetal life. The aim of the study was to examine regional cerebral blood flow (RCBF), histological changes, and cerebral brain metabolism in preterm lambs, and to analyze the role of oxidative stress in the first hours of postnatal life following severe fetal asphyxia. Eighteen chronically instrumented newborn lambs were randomly assigned to either a control group or the hypoxic-ischemic (HI) group, in which case fetal asphyxia was induced just before delivery. All the animals were maintained on intermittent positive pressure ventilation for 3 h after delivery. During the HI insult, the injured group developed acidosis, hypoxia, hypercapnia, lactic acidosis, and tachycardia (relative to the control group), without hypotension. The intermittent positive pressure ventilation transiently improved gas exchange and cardiovascular parameters. After HI injury and during ventilatory support, there continued to be an increased RCBF in inner regions among the HI group, but no significant differences were detected in cortical flow compared to the control group. Also, the magnitude of the increase in TUNEL positive cells (apoptosis) and antioxidant enzymes, and decrease of ATP reserves was significantly greater in the brain regions where the RCBF was not higher. In conclusion, our findings identify early metabolic, histological, and hemodynamic changes involved in brain damage in premature asphyxiated lambs. Such changes have been described in human neonates, so our model could be useful to test the safety and the effectiveness of different neuroprotective or ventilation strategies applied in the first hours after fetal HI injury.
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Affiliation(s)
- Carmen Rey-Santano
- Research Unit on Experimental Respiratory Physiology, Cruces Hospital Bizkaia, Spain
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13
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[Cerebral palsy and perinatal asphyxia (I--diagnosis)]. ACTA ACUST UNITED AC 2010; 38:261-77. [PMID: 20378389 DOI: 10.1016/j.gyobfe.2010.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 02/12/2010] [Indexed: 11/23/2022]
Abstract
Cerebral palsy (CP) is a group of disorders of the development of movement and posture, causing activity limitations, that are attributed to nonprogressing disturbances that occurred in the developing fetal or infant brain. The motor abnormalies are often accompanied by disturbances of sensation, perception, cognition, behavior and/or by a seizure disorder. The prevalence of CP has not decreased in developed countries over the past 30 years, despite the widespread use of electronic fetal heart rate monitoring and a 5- to 6-fold increase in the cesarean delivery rate. In the term newborn, CP may be attributed to perinatal asphyxia in case of metabolic acidosis in the cord blood (pH<7,00 and base deficit>12 mmol/L), followed by a moderate or severe neonatal encephalopathy within 24 hours and a further neurological impairement characterized by spastic quadriplegia and dyskinesia/dystonia. Dating the time of fetal asphyxia during delivery is possible when there are acute catastrophic complications during labor and unexpected acute or progressive fetal heart rate anomalies after a normal admission test, when there is a need for intensive neonatal resuscitation, a multi-organ failure within 72 hours of birth and visualization of acute non focal cerebral abnormalities, mainly by early magnetic resonance imaging (MRI). MRI sequences show either a brain-damaged pattern of the central basal ganglia, thalami and posterior limbs of internal capsules with relative cortical sparing, in acute, near-total asphyxial insults manifested by a continuous bradycardia or a pattern of cortical injury in the watershed zones and relative sparing of the central grey matter, in prolonged partial asphyxia, manifested by late or atypical variable decelerations with progressive fetal tachycardia, loss of reactivity and absent fluctuation. Prolongation of either type of asphyxial insult results in more global brain damage. In order to differentiate a CP occurring after perinatal asphyxia from other neurological sequelae in relation with infection, hemorrhage, stroke, malformations, genetic or metabolic diseases, it is essential that a definitive information from the brain by MRI and an extensive histological examination of the placenta are at disposal.
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14
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Scafidi J, Fagel DM, Ment LR, Vaccarino FM. Modeling premature brain injury and recovery. Int J Dev Neurosci 2009; 27:863-71. [PMID: 19482072 DOI: 10.1016/j.ijdevneu.2009.05.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 05/20/2009] [Indexed: 10/20/2022] Open
Abstract
Premature birth is a growing and significant public health problem because of the large number of infants that survive with neurodevelopmental sequelae from brain injury. Recent advances in neuroimaging have shown that although some neuroanatomical structures are altered, others improve over time. This review outlines recent insights into brain structure and function in these preterm infants at school age and relevant animal models. These animal models have provided scientists with an opportunity to explore in depth the molecular and cellular mechanisms of injury as well as the potential of the brain for recovery. The endogenous potential that the brain has for neurogenesis and gliogenesis, and how environment contributes to recovery, are also outlined. These preclinical models will provide important insights into the genetic and epigenetic mechanisms responsible for variable degrees of injury and recovery, permitting the exploration of targeted therapies to facilitate recovery in the developing preterm brain.
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Affiliation(s)
- Joey Scafidi
- Center for Neuroscience Research, Children's National Medical Center, Washington, DC 20010, USA
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Riddle A, Ling Luo N, Manese M, Beardsley DJ, Green L, Rorvik DA, Kelly KA, Barlow CH, Kelly JJ, Hohimer AR, Back SA. Spatial heterogeneity in oligodendrocyte lineage maturation and not cerebral blood flow predicts fetal ovine periventricular white matter injury. J Neurosci 2006; 26:3045-55. [PMID: 16540583 PMCID: PMC6673975 DOI: 10.1523/jneurosci.5200-05.2006] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 01/23/2006] [Accepted: 01/24/2006] [Indexed: 11/21/2022] Open
Abstract
Although periventricular white matter injury (PWMI) is the leading cause of chronic neurological disability and cerebral palsy in survivors of premature birth, the cellular-molecular mechanisms by which ischemia-reperfusion contributes to the pathogenesis of PWMI are not well defined. To define pathophysiologic relationships among ischemia, acute cerebral white matter damage, and vulnerable target populations, we used a global cerebral ischemia-reperfusion model in the instrumented 0.65 gestation fetal sheep. We developed a novel method to make repeated measurements of cerebral blood flow using fluorescently labeled microspheres to resolve the spatial heterogeneity of flow in situ in three-dimensional space. Basal flow in the periventricular white matter (PVWM) was significantly lower than in the cerebral cortex. During global cerebral ischemia induced by carotid occlusion, flow to all regions was reduced by nearly 90%. Ischemia of 30 or 37 min duration generated selective graded injury to frontal and parietal PVWM, two regions of predilection for human PWMI. Injury was proportional to the duration of ischemia and increased markedly with 45 min of ischemia to extensively damage cortical and subcortical gray matter. Surprisingly, the distribution of PVWM damage was not uniform and not explained by heterogeneity in the degree of white matter ischemia. Rather, the extent of white matter damage coincided with the presence of a susceptible population of late oligodendrocyte progenitors. These data support that although ischemia is necessary to generate PWMI, the presence of susceptible populations of oligodendrocyte progenitors underlies regional predilection to injury.
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Back SA. Perinatal white matter injury: The changing spectrum of pathology and emerging insights into pathogenetic mechanisms. ACTA ACUST UNITED AC 2006; 12:129-40. [PMID: 16807910 DOI: 10.1002/mrdd.20107] [Citation(s) in RCA: 256] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Perinatal brain injury in survivors of premature birth has a unique and unexplained predilection for periventricular cerebral white matter. Periventricular white-matter injury (PWMI) is now the most common cause of brain injury in preterm infants and the leading cause of chronic neurological morbidity. The spectrum of chronic PWMI includes focal cystic necrotic lesions (periventricular leukomalacia; PVL) and diffuses myelination disturbances. Recent neuroimaging studies support that the incidence of PVL is declining, whereas focal or diffuse noncystic injury is emerging as the predominant lesion. Factors that predispose to PVL during prematurity include hypoxia, ischemia, and maternal-fetal infection. In a significant number of infants, PWMI appears to be initiated by perturbations in cerebral blood flow that reflect anatomic and physiological immaturity of the vasculature. Ischemic cerebral white matter is susceptible to pronounced free radical-mediated injury that particularly targets immature stages of the oligodendrocyte lineage. Emerging experimental data supports that pronounced ischemia in the periventricular white matter is necessary, but not sufficient to generate PWMI. The developmental predilection for PWMI to occur during prematurity appears to be related to both the timing of appearance and regional distribution of susceptible oligodendrocyte progenitors. Injury to oligodendrocyte progenitors may contribute to the pathogenesis of PWMI by disrupting the maturation of myelin-forming oligodendrocytes. Chemical mediators that may contribute to white-matter injury include reactive oxygen species glutamate, cytokines, and adenosine. As our understanding of the pathogenesis of PWMI improves, it is anticipated that new strategies for directly preventing brain injury in premature infants will develop.
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Affiliation(s)
- Stephen A Back
- Department of Pediatrics, Oregon Health & Sciences University, Portland, Oregon, USA.
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17
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Abstract
Studies in the research laboratory have demonstrated the complex relationship between fetal and newborn asphyxia and brain damage, a balance between the degree, duration and nature of the asphyxia and the quality of the cardiovascular compensatory response. Clinical studies would support the contention that the human fetus and newborn behave in a similar manner. An accurate diagnosis of asphyxia requires a blood gas and acid base assessment. The clinical classification of fetal asphyxia is based on a measure of metabolic acidosis to confirm that fetal asphyxia has occurred and the expression of neonatal encephalopathy and other organ system complications to express the severity of the asphyxia. The prevalence of fetal asphyxia at delivery is at term, 25 per 1000 live births of whom 15% are moderate or severe; and in the preterm, 73 per 1000 live births of whom 50% are moderate or severe. It remains to be determined how often the asphyxia recognized at delivery may have been present before the onset of labor. There is a growing body of indirect and direct evidence to support the contention that antepartum fetal asphyxia is important in the occurrence of brain damage. Although much of the brain damage observed in the newborn reflects events that occurred before delivery, newborn asphyxia and hypotension, particularly in the preterm newborn, may contribute to the brain damage accounting for deficits in surviving children.
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Affiliation(s)
- James A Low
- Department of Obstetrics and Gynaecology, Queen's University, Ontario, Canada.
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Rentmeister K, Schmidbauer S, Hewicker-Trautwein M, Tipold A. Periventricular and Subcortical Leukoencephalopathy in two Dachshund Puppies. ACTA ACUST UNITED AC 2004; 51:327-31. [PMID: 15533112 DOI: 10.1111/j.1439-0442.2004.00640.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two wirehaired dachshund puppies were presented with generalized tremor and gait abnormalities characterized by mild ataxia, tetraparesis and slightly abnormal proprioception. Neurological examination led to the suspicion of a diffuse generalized white matter lesion. Computerized tomography and pathological examination revealed a remarkable unilateral dilatation of the lateral ventricles in each dog. Histopathological examination showed a severe reduction of stainable myelin, widespread mild perineuronal oedema with vacuolations and multifocal reactive astrocytosis affecting the subcortical and deep periventricular white, and to a lesser degree, grey matter of the cerebral hemispheres, most prominently at the level of the optic chiasm. Axons showed a moderately reduced packing density; some axons were irregularly shaped and slightly thickened. There was no evidence of myelin breakdown products and neurones appeared to be well preserved. Brain stem, cerebellum and spinal cord were normal, as was the peripheral nervous system. This leukoencephalopathy in two dachshund puppies most closely resembles human periventricular leukomalacia caused by pre- or perinatal hypoxia-ischaemia.
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Affiliation(s)
- K Rentmeister
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, D-30173 Hannover, Germany.
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Nguyen PN, Billiards SS, Walker DW, Hirst JJ. Changes in 5alpha-pregnane steroids and neurosteroidogenic enzyme expression in fetal sheep with umbilicoplacental embolization. Pediatr Res 2003; 54:840-7. [PMID: 12930920 DOI: 10.1203/01.pdr.0000088066.47755.36] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pregnane steroids have sedative and neuroprotective effects on the brain, due to interactions with the steroid-binding site of the GABAA receptor. In the adult brain, synthesis of the pregnane steroids is increased in response to stress. Therefore, we have used umbilicoplacental embolization to mimic chronic placental insufficiency during late gestation in sheep, to investigate the expression of the steroidogenic enzymes p450scc, 5alpha-reductase type I (5alphaRI), 5alpha-reductase type II (5alphaRII), and allopregnanolone (AP) content in the fetal brain. Umbilicoplacental embolization was induced from 114 d gestation (term approximately 147 d) by daily injection of inert microspheres into the umbilical artery and continued for 17-23 d. Fetal arterial oxygen saturation was reduced to approximately 60% of the preembolization value in each fetus, with a significant reduction in blood arterial Po2, pH, and plasma glucose concentrations (p < 0.05) and a significant increase in blood arterial Pco2 and plasma lactate concentrations (p < 0.05). At postmortem at 131-137 d gestation, embolized fetuses were growth-restricted (2.10 +/- 0.14 kg, n = 5) compared with age-matched controls (4.43 +/- 0.56 kg, n = 7, p < 0.05). Umbilicoplacental embolized fetuses showed increased P450scc expression in the primary motor cortex; 5alphaRI expression was not changed in any of the regions examined, whereas 5alphaRII expression was markedly increased in all brain regions. Brain AP content did not significantly change, whereas plasma concentrations were increased. These findings suggest that the increased expression of p450scc and 5alphaRII may be a response that maintains AP concentration in the fetal brain after compromised placental function and/or intrauterine stress.
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Affiliation(s)
- Phuong N Nguyen
- Department of Physiology, Monash University, Clayton Victoria 3800, Australia
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20
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Petersson KH, Pinar H, Stopa EG, Faris RA, Sadowska GB, Hanumara RC, Stonestreet BS. White matter injury after cerebral ischemia in ovine fetuses. Pediatr Res 2002; 51:768-76. [PMID: 12032276 DOI: 10.1203/00006450-200206000-00019] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effects of cerebral ischemia on white matter changes in ovine fetuses were examined after exposure to bilateral carotid artery occlusion. Fetal sheep were exposed to 30 min of ischemia followed by 48 (I/R-48, n = 8) or 72 (I/R-72, n = 10) h of reperfusion or control sham treatment (control, n = 4). Serial coronal sections stained with Luxol fast blue/hematoxylin and eosin were scored for white matter, cerebral cortical, and hippocampal lesions. All areas received graded pathologic scores of 0 to 5, reflecting the degree of injury where 0 = 0%, 1 = 1% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, 4 = 76% to 95%, and 5 = 96% to 100% of the area damaged. Dual-label immunofluorescence using antibodies against glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) were used to characterize white matter lesions. Basic fibroblast growth factor (FGF-2) was measured in the frontal cortex by ELISA. Results of the pathologic scores showed that the white matter of the I/R-72 (2.74 +/- 0.53, mean +/- SEM) was more (p < 0.05) damaged when compared with the control (0.80 +/- 0.33) group. Cortical lesions were greater (p < 0.05) in the I/R-48 (2.12 +/- 0.35) than the control (0.93 +/- 0.09) group. White matter lesions were characterized by reactive GFAP-positive astrocytes and a loss of MBP in oligodendrocytes. The ratio of MBP to GFAP decreased (p < 0.05) as a function of ischemia, indicative of a proportionally greater loss of MBP than GFAP. FGF-2 concentrations were higher (p < 0.05) in the I/R-72 than the control group and there was a direct correlation between the pathologic scores (PS) and FGF-2 concentrations (FGF-2 = e((1.6 PS-0.90)) + 743, n = 17, r = 0.73, p < 0.001). We conclude that carotid artery occlusion results in quantifiable white matter lesions that are associated with a loss of MBP from myelin, and that FGF-2, a purported mediator of recovery from brain injury in adult subjects, increases in concentration in proportion to the severity of brain damage in the fetus.
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Affiliation(s)
- Katherine H Petersson
- Department of Pediatrics, Brown University School of Medicine, Providence, Rhode Island 02906, USA
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21
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Kirimi E, Tuncer O, Atas B, Sakarya ME, Ceylan A. Clinical value of color Doppler ultrasonography measurements of full-term newborns with perinatal asphyxia and hypoxic ischemic encephalopathy in the first 12 hours of life and long-term prognosis. TOHOKU J EXP MED 2002; 197:27-33. [PMID: 12180790 DOI: 10.1620/tjem.197.27] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The cerebral blood flow velocities (CBFV) of infants with perinatal asphyxia and hypoxic ischemic encephalopathy (HIE) in the first 12 hours of their lives have been the chief focus of our concern in this study. Cerebral ischemia which can develop in the earlier hours of HIE, and the detection and diagnosis of this condition with color Doppler ultrasonography (cD-USG) will be put into discussion. Twenty-three full-term newborn infants who had perinatal asphyxia and HIE together with a control group constituting twenty full-term newborn infants who produced no problems, were included in our study. All of the infants underwent cD-USG in the postpartum period of the first 12 hours (mean 8.4 hours). Measurements being based upon peak systolic velocity (PSV), end diastolic velocity (EDV) and Pouecelout's resistive index (RI) in anterior and middle cerebral arteries were conducted. The infants, having been discharged from the unit they were followed up for mean 9.8 months in the outpatient clinic. PSV and EDV counts in the postpartum first 12 hours of 23 infants who were detected to have HIE were found to be significantly lower compared to the control group, whereas RI counts were found to be significantly higher (p < 0.05). The counts obtained from the right and left cerebral arteries of the infants with HIE were found to be corraleted with each others. The neonates in the patient group were observed to have gone through this prognosis: Three of them died, three of them had cerebral palsy, one of them had infantile spasms, and three of them had developmental retardation. When we compared the CBFV of the 10 neonates who had poor prognosis, retrospectively with the other 13 neonates who had good prognosis, PSV and EDV were found to be significantly lower and RI significantly higher (p < 0.05). In the light of the data we have obtained, cD-USG can be considered to be a highly practical device in evaluating CBVF of the infants with HIE. A skillful detection of the decrease in cerebral blood flow which can develop in the postasphyxial first 12 hours and the prospective treatments being based upon this approach would contribute to the diagnosis, treatment and prognosis of such cases.
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Affiliation(s)
- Ercan Kirimi
- Department of Pediatrics, Yüzüncü Yil University Hospital, Van, Turkey.
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22
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Garnier Y, Löbbert T, Jensen A, Berger R. Lubeluzole pretreatment does not provide neuroprotection against transient global cerebral ischemia in fetal sheep near term. Pediatr Res 2002; 51:517-22. [PMID: 11919339 DOI: 10.1203/00006450-200204000-00019] [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: 11/06/2022]
Abstract
The aim of the present study was to test the neuroprotective effect of the novel benzothiazol compound lubeluzole on neuronal cell damage in fetal sheep arising from global cerebral ischemia. Thirteen fetal sheep were prepared at a mean gestational age of 127 +/- 1 d (term is at 147 d). Six fetuses were treated with lubeluzole (0.33 mg/kg estimated body weight) before induction of global cerebral ischemia (-90, -60, and -30 min), while the remainder (n = 7) received solvent. Cerebral ischemia was induced by occluding both carotid arteries for 30 min. Cerebral blood flow was measured by injecting radio-labeled microspheres before (-90 min), during (+3 min and +27 min), and after (+40 min, +3 h, and +72 h) cerebral ischemia. Neuronal cell damage was assessed in the cerebrum and deeper brain structures by light microscopy. Values are given as means +/- SD. In control fetuses, blood flow to the cerebrum was reduced from 100 +/- 25 mL.100 g(-1) min(-1) to less than 20 mL.100 g(-1) min(-1) during ischemia. Shortly after ischemia, hyperperfusion occurred (217 +/- 66 mL.100 g(-1)min(-1)) followed by a tendency toward hypoperfusion (72 +/- 17 mL.100 g(-1) min(-1)) later on (+3 h). Significant differences in blood flow to the various brain structures between the control and study groups could not be observed. Neuronal cell damage was concentrated in the parasagittal regions of the cerebrum. Preischemic application of lubeluzole did not have any effect on the extent of neuronal cell damage. From these results, we conclude that pretreatment with lubeluzole fails to protect the brain of fetal sheep near term from injury after transient global cerebral ischemia. However, because the observation period lasted only 3 d, a possible effect of lubeluzole on pathophysiological mechanisms inducing delayed neuronal cell death cannot be fully excluded.
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Affiliation(s)
- Yves Garnier
- Department of Obstetrics and Gynecology, Ruhr-Universität Bochum, Bochum, Germany
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23
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Affiliation(s)
- S A Back
- Department of Pediatrics, NRC-5, Oregon Health Sciences University and Doernbecher Children's Hospital, 3181 SW Sam Jackson Park Road, Portland, OR 97201-3098, USA.
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24
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van Cappellen van Walsum AM, Jongsma HW, Wevers RA, Nijhuis JG, Crevels J, Engelke UF, Moolenaar SH, Oeseburg B, Nijland R. Hypoxia in fetal lambs: a study with (1)H-MNR spectroscopy of cerebrospinal fluid. Pediatr Res 2001; 49:698-704. [PMID: 11328955 DOI: 10.1203/00006450-200105000-00015] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In fetal lambs, severe hypoxia (SH) will lead to brain damage. Mild hypoxia (MH) is thought to be relatively safe for the fetal brain because compensating mechanisms are activated. We questioned whether MH, leading to mild acidosis, induces changes in cerebral metabolism. Metabolites in cerebrospinal fluid (CSF) samples, as analyzed by proton magnetic resonance spectroscopy, were studied in two groups of seven anesthetized near-term fetal lambs. In group I, SH leading to acidosis with an arterial pH <7.1 was achieved. In group II, MH with an intended pH of 7.23--7.27 was reached [start of MH (SMH)], and maintained during 2 h [end of MH (EMH)]. During SH, choline levels in CSF, a possible indicator of cell membrane damage, were increased. Both during SH and at EMH, CSF levels of lactic acid, alanine, phenylalanine, tyrosine, lysine, branched chain amino acids, and hypoxanthine were increased compared with control values and with SMH, respectively. At EMH, the hypoxanthine CSF-to-blood ratio was increased as compared with SMH. These results indicate that prolonged MH leads to energy degradation in the fetal lamb brain and may not be as safe as assumed.
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25
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Keunen H, Hasaart TH. Fetal arterial pressure and heart rate changes in surviving and non-surviving immature fetal sheep following brief repeated total umbilical cord occlusions. Eur J Obstet Gynecol Reprod Biol 1999; 87:151-7. [PMID: 10597965 DOI: 10.1016/s0301-2115(99)00098-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To describe the changes in fetal heart rate and mean arterial pressure during repetitive total umbilical cord occlusions in immature sheep fetuses, resulting in severe asphyxia or fetal death. To describe the relationship between these changes and concurrent changes in acid-base status. STUDY DESIGN We performed brief repeated total umbilical cord occlusions, two out of every five min, in 14 immature sheep fetuses (at 90 days of gestation), until fetal mean arterial pressure dropped below 50% of baseline value during two successive occlusions. Fetal blood gas analyses were performed at regular intervals just before cord occlusions. RESULTS Progressive acidemia and hypotension developed with ongoing occlusions. The degree of hypotension during occlusions increased with ongoing occlusions. The minimum fetal arterial blood pressure during occlusions correlated well with the progressive acidemia. Six fetuses died at the end of the repetitive occlusion period. In the non-survivors, acidemia was more severe and paCO2 gradually increased during the entire repetitive occlusion period. In the survivors group, a period of transient hypoxia and hypotension was observed with a nadir at +60 min following the final occlusion. CONCLUSION Repetitive umbilical cord occlusions in immature sheep fetuses resulted in repetitive periods of hypotension, bradycardia, progressive fetal acidemia and ultimately fetal demise. Minimum fetal arterial blood pressure during occlusions correlated well with the progressive fetal acidemia.
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Affiliation(s)
- H Keunen
- Department of Obstetrics and Gynecology, University Hospital Maastricht, The Netherlands
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26
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van de Bor M, Meinesz J, Benders MJ, Steendijk P, Lopes Cardozo RH, van Bel F. Electrocortical brain activity during hypoxia and hypotension in anesthetized newborn lambs. Early Hum Dev 1999; 55:237-45. [PMID: 10463788 DOI: 10.1016/s0378-3782(99)00022-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Blood gas and blood pressure disturbances do influence cerebral blood flow in newborns. To what extent cerebral blood flow changes affect electrocortical brain activity remains uncertain. We studied the effect of severe hypoxia and hemorrhagic hypotension on carotid artery blood flow and electrocortical brain activity in newborn anesthetized lambs. During hypoxia carotid artery blood flow increased significantly, whereas electrocortical brain activity remained unchanged. The hemorrhagic hypotension study showed that the lower limit of the autoregulatory ability of the cerebral vascular bed was 60 mmHg. Electrocortical brain activity however remained stable until mean aortic pressure had dropped below 30 mmHg, carotid artery blood flow below 10.6 ml/kg/min, and cerebral oxygen delivery below 1.4 ml/kg/min.
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Affiliation(s)
- M van de Bor
- Department of Pediatrics, University of Nijmegen, University Hospital Nijmegen, The Netherlands.
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27
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Walker DW, Curtis B, Lacey B, Nitsos I. Kynurenic acid in brain and cerebrospinal fluid of fetal, newborn, and adult sheep and effects of placental embolization. Pediatr Res 1999; 45:820-6. [PMID: 10367772 DOI: 10.1203/00006450-199906000-00007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Concentrations of the endogenous glutamate receptor antagonist kynurenic acid (KA) were measured in various brain regions and in cisternal cerebrospinal fluid of fetal, newborn, and adult sheep. KA concentrations were significantly higher in the fetal brain and cerebrospinal fluid at 90 and 140 d gestation compared with postnatal ages. In fetuses of 132-139 d gestation, KA concentrations in cerebrospinal fluid collected by drainage from an indwelling cisternal catheter increased significantly after infusion of the organic acid transport inhibitor probenecid (100 or 200 mg/kg, i.v.) indicating active transport of KA out of the fetal brain. In fetuses in which the umbilical circulation had been chronically restricted from 120 to 140 d gestation by partial embolization of the placenta, plasma concentrations of the KA precursor kynurenine were significantly lower than in control fetuses, and KA concentrations in the hypothalamus and hippocampus were significantly reduced; other brain regions were not affected. These results indicate that the production of KA is higher in the fetal brain compared with the newborn and adult brain. Because KA diminishes the risk of excitotoxic neuronal damage under hypoxic-ischemic conditions, the high levels of KA in the brain before birth may have a neuroprotective function. The decrease of KA concentrations in the hypothalamus and hippocampus after umbilical embolization suggests that, after chronic hypoxia in utero, these regions of the brain may become more vulnerable to subsequent episodes of acute hypoxia or ischemia encountered in late gestation or during parturition.
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Affiliation(s)
- D W Walker
- Department of Physiology, Monash University, Clayton, Melbourne, Australia
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28
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Braaksma MA, Douma BR, Nyakas C, Luiten PG, Aarnoudse JG. Delayed neuronal migration of protein kinase Cgamma immunoreactive cells in hippocampal CA1 area after 48 h of moderate hypoxemia in the near term ovine fetus. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1999; 114:253-60. [PMID: 10320764 DOI: 10.1016/s0165-3806(99)00011-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The brain is uniquely sensitive to disturbances in energy and oxygen supply, particularly during the early stage of life. Since hypoxemia can indirectly activate the intracellular messenger protein kinase C (PKC), we studied the PKCgamma-immunoreaction in the fetal hippocampal CA1 region of naive (n=4), instrumented control (n=7), and instrumented hypoxemic fetuses (n=14), at a mean gestational age of 127 days. Forty-eight hours of mild to moderate hypoxemia, were followed by a 48-h recovery period. Hypoxemia resulted in an increase in carotid blood flow (137% of control), and a shift towards a higher percentage of high-voltage electrocortical activity. After recovery, the fetal brain was fixated by perfusion of both carotid arteries, sectioned and immunostained for PKCgamma. The distribution of PKCgamma-immunoreactive cells was significantly changed after 48 h of hypoxemia in that the migration of cells (from the ventricular region towards the stratum pyramidale) was delayed (p<0.01) compared to naive and instrumented control animals. In contrast to the distribution, the relative total optical density of PKCgamma-ir cells and fibres in the CA1 hippocampal area was not significant different between the animal groups. We conclude that hypoxemia delayed migration of PKCgamma-ir cells, without neuronal degeneration.
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Affiliation(s)
- M A Braaksma
- Departments of Obstetrics and Gynaecology, University of Groningen, Groningen, Netherlands.
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29
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Li YB, Kaur C, Ling EA. Neuronal degeneration and microglial reaction in the fetal and postnatal rat brain after transient maternal hypoxia. Neurosci Res 1998; 32:137-48. [PMID: 9858021 DOI: 10.1016/s0168-0102(98)00077-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study examined the neuropathological changes in different areas of the brain of fetal and postnatal rats after transient maternal hypoxia. At different time intervals following hypoxia, reactive microglia as determined immunohistochemically with the antibody OX-42 that recognizes complement type three (CR3) receptors, responded vigorously to the hypoxic stress. Microglial activation was particularly evident in the cingulate cortex and the corpus callosum between 3 h and 14 days after hypoxia. Massive cell degeneration as determined ultrastructurally and significant neuronal loss as evaluated by cell counts were observed in the cingulate cortex at 1 and 3 days after hypoxic insults; thereafter, however, the neuronal density was restored to normal levels. Present results suggest that the cingulate cortex is most vulnerable to the hypoxic injury probably due to a redistribution of cerebral blood flow and/or metabolic changes. Besides being involved in the phagocytosis of cellular debris, it is suggested that the reactive microglial cells may have both neurotoxic and neurotrophic functions.
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Affiliation(s)
- Y B Li
- Department of Anatomy, Faculty of Medicine, National University of Singapore, Singapore
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30
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Reddy K, Mallard C, Guan J, Marks K, Bennet L, Gunning M, Gunn A, Gluckman P, Williams C. Maturational change in the cortical response to hypoperfusion injury in the fetal sheep. Pediatr Res 1998; 43:674-82. [PMID: 9585015 DOI: 10.1203/00006450-199805000-00017] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A characteristic of perinatal encephalopathies are the distinct patterns of neuronal and glial cell loss. Cerebral hypoperfusion is thought to be a major cause of these lesions. Gestational age is likely to influence outcome. This study compares the cortical electrophysiologic and histopathologic responses to hypoperfusion injury between preterm and near term fetuses. Chronically instrumented 0.65 (93-99-d, n = 9) and 0.9 (119-133-d, n = 6) gestation fetal sheep underwent 30 min of cerebral hypoperfusion injury. The parasagittal cortical EEG and impedance (measure of cytotoxic edema) responses plus histologic outcome (3 d) were compared. The acute rise in impedance was similar in amplitude, but the onset was delayed (5.0 +/- 0.7 versus 9.1 +/- 1.1 min, p < 0.05) in the preterm fetuses relative to those near term. In contrast the extent of the secondary rise was reduced (p < 0.01) and peaked earlier in the preterm fetuses (19.8 +/- 1.0 versus 40.5 +/- 3.5 h, p < 0.01). Both groups had a similar fall in EEG spectral edge frequency. The preterm fetuses had a milder loss of EEG intensity at 72 h (-7.7 +/- 1.5 versus -12.8 +/- 0.9 dB, p < 0.05). At both ages there was a predominantly parasagittal cortical distribution of damage with a similar pattern of neuronal loss in the thalamus and striatum. There was extensive selective neuronal loss within the upper layers of the cortex in those near term. In contrast the preterm fetuses developed subcortical infarcts (p < 0.05). The cortical response to injury altered during the last trimester. The results suggest the severity of the delayed phase of cortical neuronal injury and selective neuronal loss increased near term. In contrast, the preterm fetuses had a more rapidly evolving injury leading to necrosis of the subcortical white matter.
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Affiliation(s)
- K Reddy
- Research Centre for Developmental Medicine and Biology, Department of Paediatrics, University of Auckland, New Zealand
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Henderson JL, Reynolds JD, Dexter F, Atkins B, Hrdy J, Poduska D, Penning DH. Chronic hypoxemia causes extracellular glutamate concentration to increase in the cerebral cortex of the near-term fetal sheep. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1998; 105:287-93. [PMID: 9541746 DOI: 10.1016/s0165-3806(97)00192-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fetal hypoxia is an important cause of neurologic morbidity and mortality. Hypoxia-induced increase in extracellular glutamate concentration can lead to excitotoxic neuronal death in adults. The objective of this study was to test whether chronic fetal hypoxemia increases extracellular glutamate concentration in the unanesthetized intact cerebral cortex of the near-term fetal sheep. Microdialysis probes were implanted into the parasagittal parietal cortex and periventricular white matter of near-term fetal sheep. At 124 +/- 1 days of gestation, extracellular glutamate concentration was determined before and during 24 h of fetal hypoxemia. Chronic hypoxemia was produced by tightening a vascular occluder placed around the maternal common iliac artery. Larger decreases in fetal arterial oxygen content were associated with larger increases in extracellular glutamate concentration in the parietal cortex (Kendall's tau = 0.81, N = 7, p = 0.005). No such relationship was detected in the periventricular white matter. Chronic hypoxemia increases extracellular glutamate concentration in the intact cerebral cortex of the unanesthetized near-term fetal sheep.
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Affiliation(s)
- J L Henderson
- Department of Obstetrics and Gynecology, University of Iowa, College of Medicine, Iowa City, USA
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Mallard EC, Rees S, Stringer M, Cock ML, Harding R. Effects of chronic placental insufficiency on brain development in fetal sheep. Pediatr Res 1998; 43:262-70. [PMID: 9475295 DOI: 10.1203/00006450-199802000-00018] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Clinical evidence has linked intrauterine compromise such as fetal hypoxemia to poor neurologic outcome in the newborn. In this study we examined the effects of inducing chronic fetal hypoxemia by impairment of placental function on brain development in fetal sheep. Placental insufficiency was induced from 120 to 140 d of gestation (term = 145-148 d) by injection of microspheres into the umbilical circulation in five fetal sheep. Fetal partial pressure of oxygen, PaO2, was reduced from 24.1 +/- 0.5 mm Hg before embolization to 14.8 +/- 0.4 mm Hg after embolization (p < 0.05). In another three fetuses a similar level of hypoxemia (PaO2, 13.8 +/- 0.4 mm Hg) occurred spontaneously. At 140 d of gestation the fetal brains were perfused with fixatives and compared with five control fetuses for the assessment of structural and immunohistochemical alterations. Hypoxemic fetuses demonstrated severe gliosis in the cerebral cortex and reduced myelination of subcortical white matter as visualized by glial fibrillary acidic protein and myelin basic protein staining, respectively (p < 0.05). White matter lesions were observed in two fetuses. The diameter of cerebral capillaries was increased in hypoxemic fetuses (p < 0.05), but there was no change in the number of nitric oxide synthase immunoreactive cells. Growth of neuronal processes was affected in the cerebellum, where there was also a reduction in the number of Purkinje neurons (p < 0.05). These results show that a prolonged period of placental insufficiency, resulting in moderate fetal hypoxemia during the last third of gestation, can affect neurodevelopmental processes that occur late in gestation such as myelination and growth of the cerebellum. This prenatal damage could affect neural connectivity and have functional consequences after birth.
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Affiliation(s)
- E C Mallard
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria, Australia
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Ikeda T, Murata Y, Quilligan EJ, Choi BH, Parer JT, Doi S, Park SD. Physiologic and histologic changes in near-term fetal lambs exposed to asphyxia by partial umbilical cord occlusion. Am J Obstet Gynecol 1998; 178:24-32. [PMID: 9465798 DOI: 10.1016/s0002-9378(98)70621-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Our purpose was to characterize the histologic changes in the asphyxiated fetal lamb brain and to correlate the severity of these changes with fetal physiologic parameters during and after asphyxia. STUDY DESIGN Seventeen near-term fetuses were used for analysis: control group without manipulation (n = 4, 132 +/- 1.1 days of gestation at autopsy, mean +/- SEM), sham-asphyxia control group (n = 3, 132 +/- 1.3 days), and asphyxiated group, which successfully survived 72 hours after asphyxia (n = 10, 130 +/- 1.0 days). Asphyxia was produced by umbilical cord occlusion lasting for approximately 60 minutes until fetal arterial pH diminished to < 6.9 and base excess to < -20 mEq/L. Fetal heart rate, blood pressure, and electrocorticographic activity were continuously monitored. The fetuses were killed 72 hours after asphyxia, and the brains were fixed in formalin and processed for histologic and immunocytochemical studies. RESULTS Neuropathologic changes varied from case to case, ranging from almost total infarction of cortical and subcortical structures to extremely subtle and patchy white matter alterations characterized by slight vacuolization of the white matter or slight to moderate increases in cellularity confined to the junction of cerebral cortex and white matter. Even fetuses that showed full recovery of all physiologic parameters, including electrocorticographic activity, demonstrated subtle but distinct white matter lesions. The gray matter, including the hippocampal neurons, was generally spared in these cases. Electrocorticographic parameters, duration of hypotension during asphyxia, and delayed recovery of blood lactate concentrations correlated well with the histologic grading of brain damage. CONCLUSIONS Asphyxia by partial umbilical cord occlusion in near-term fetal lambs produces variable neuropathologic changes. The mildest change is a white matter lesion characterized by vacuolization and loss of myelin or by increased cellularity in the damaged regions.
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Affiliation(s)
- T Ikeda
- Department of Obstetrics and Gynecology, University of California, Irvine, USA
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Rees S, Stringer M, Just Y, Hooper SB, Harding R. The vulnerability of the fetal sheep brain to hypoxemia at mid-gestation. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1997; 103:103-18. [PMID: 9427475 DOI: 10.1016/s0165-3806(97)81787-7] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Our aim was to test the hypothesis that a brief episode of hypoxemia near mid-gestation in fetal sheep will result in damage to the fetal brain with the extent and type of damage in any particular region being related to the developmental processes occurring at the time of the insult. Hypoxemia was induced, sufficient to reduce arterial O2 content by approximately 50%, by restricting utero-placental blood flow in 14 chronically catheterised fetuses for 6 h or 12 h at 84 days of gestation (term 145-8 days). Age-matched fetuses (n = 14; 4 operated and 10 unoperated) were used as controls. Fetuses were killed 7 days after being exposed to hypoxemia, and brains removed for histological analysis at the light and ultrastructural levels. Body weights of hypoxemic fetuses did not differ significantly from controls but brain weights were significantly reduced both in absolute terms and when expressed in relation to body weight (P < 0.05). Most fetuses exposed to hypoxemia sustained no gross brain damage. However, in one hypoxemic fetus from a multiple pregnancy there was extensive leucomalacia in the cortical white matter; mild focal damage was seen in another 8 hypoxemic fetuses. In the cerebral cortex (frontal lobe) the surface folding index was significantly reduced (P < 0.05) in hypoxemic fetuses compared to controls suggesting that gyral formation had been delayed. In these fetuses there were also degenerating neurons in the deeper cortical layers. In the hippocampus of hypoxemic fetuses there was a delay (P < 0.05), compared to controls, in the migration of cells from the germinal layer to the pyramidal layer in the CA1 region, and decreases (P < 0.05) in the density (area1) of neurons in the pyramidal layer and in the width of stratum oriens. In the cerebellum of hypoxemic fetuses there was a decrease (P < 0.05), compared to controls, in the density (area1) of mitotic bodies in the external granule cell layer. However, there were no significant differences in the number of pyknotic cells in this layer, in the density of Purkinje cells, in their somal area, or in the width of the external granule cell or molecular layers. There was an increase (P < 0.05) in the proportion of the brain parenchyma occupied by blood vessels in both the hippocampus and cortex of hypoxemic fetuses compared to controls. This study has shown that an hypoxemic insult near mid-gestation can result, one week later, in white matter damage and in neuronal death in the hippocampus and to a lesser extent in the cerebral cortex and cerebellum. It can also retard neuronal migration and the growth of neural processes in the hippocampus where development is well established at this age. Such brain damage could result in less than optimal neuronal connectivity and could affect function postnatally.
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Affiliation(s)
- S Rees
- Department of Anatomy and Cell Biology, University of Melbourne, Victoria, Australia.
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Keunen H, Blanco CE, van Reempts JL, Hasaart TH. Absence of neuronal damage after umbilical cord occlusion of 10, 15, and 20 minutes in midgestation fetal sheep. Am J Obstet Gynecol 1997; 176:515-20. [PMID: 9077598 DOI: 10.1016/s0002-9378(97)70539-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES Our purpose was to determine whether neuronal damage results after total umbilical cord occlusion of increasing duration in midgestation fetal sheep. STUDY DESIGN We performed total umbilical cord occlusion during 10 (n = 11), 15 (n = 8), or 20 (n = 4) minutes in chronically instrumented midgestation fetal sheep. Nine fetuses served as sham controls. During the experiment fetal blood pressure (mean arterial pressure) and heart rate were continuously recorded. Fetal blood gas analyses were performed at regular intervals before, during, and after the occlusion. Three days after the occlusion neuronal damage was evaluated histologically in three regions of the fetal brain. RESULTS Total umbilical cord occlusion resulted in hypotension, bradycardia, severe mixed acidemia, hypoxia, and hypercapnia. All fetuses survived the occlusion. No neuronal damage nor macroscopic intraventricular or germinal matrix hemorrhages were observed in either group. CONCLUSION Prolonging the duration of total umbilical cord occlusion in midgestation fetal sheep resulted in a progressive increase in the severity of asphyxia, not in neuronal damage.
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Affiliation(s)
- H Keunen
- Department of Obstetrics and Gynecology, University Hospital Maastricht, The Netherlands
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Abstract
This study was conducted to determine whether prenatal exposure to cocaine interferes with the development of the primate cerebral cortex. For this purpose, pregnant rhesus monkeys received cocaine orally (20 mg/kg/day in fruit or candy treats), twice a day from the 40th-102nd days of pregnancy (E40-E102), which is a period of corticogenesis in this species. The control group of pregnant animals received fruit or candy treats only. On E64 and E65, all animals received intravenous injections of [3H]thymidine. Monkeys were allowed to deliver at term. The offspring were sacrificed at age 2 months, and their brains were processed for histology and autoradiography. The analysis of cresyl violet-stained sections showed that prenatal treatment with cocaine significantly altered lamination of the primate cerebral cortex, in some cases completely blending distinction between individual layers. In addition, autoradiographic analysis revealed that in the control animals, [3H]thymidine labeling concentrated in cortical layers V and/or IV depending on the cytoarchitectonic area observed. In contrast, drug-treated animals displayed labeled cells in the white matter and cortical layer VI in addition to layers V and IV, suggesting inability of cortical cells to reach proper cortical layers. The number of labeled cells was also much lower in these animals. Finally, immunocytochemical studies with antisera directed toward glial fibrillary acidic protein showed that prenatal exposure to cocaine had dramatic effect on the glial fibers normally observed in the upper cortical layers. In many cortical regions of cocaine-treated animals, we observed practically no such fibers. This study demonstrates that cocaine administered during pregnancy can significantly affect the development of the primate cerebral cortex.
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Affiliation(s)
- M S Lidow
- Section of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Antepartale Diagnostik von Hirnschäden des Feten. Arch Gynecol Obstet 1995; 256:S43-S49. [PMID: 27696029 DOI: 10.1007/bf02201937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Matsuda Y, Patrick J, Carmichael L, Fraher L, Richardson B. Recovery of the ovine fetus from sustained hypoxia: effects on endocrine, cardiovascular, and biophysical activity. Am J Obstet Gynecol 1994; 170:1433-41. [PMID: 8178886 DOI: 10.1016/s0002-9378(94)70176-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The purpose of this study was (1) to determine the ability of the ovine fetus to recover from a self-limiting asphyxial insult and (2) to monitor cardiovascular and biophysical activity as potential markers of such an insult or underlying neurologic impairment. STUDY DESIGN Nineteen fetal sheep were studied (12 hypoxia and 7 control) at 0.9 of gestation during a 24-hour control period, up to 8 hours of either sustained hypoxemia or room air, and for a 40-hour recovery period. Fetal heart rate, blood pressure, electrocortical activity, electroocular activity, and breathing movements were monitored continuously. Fetal arterial blood was sampled at set times for blood gases, pH, lactate, and catecholamine levels. RESULT Induced fetal hypoxemia resulted in a lactic metabolic acidosis that progressively worsened, with death occurring in three of the animals during the early recovery period. The remaining animals showed a rapid metabolic and endocrine normalization of values by 24 hours. Fetal cardiovascular and biophysical measurements likewise returned to control values during the early recovery period, although three animals had seizure-like activity. CONCLUSION The near-term ovine fetus surviving a sustained asphyxial insult sufficient to induce neuropathologic change within the brain demonstrates a normalization of biophysical activity during the early period of recovery, although seizure-like activity may subsequently be evident.
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Affiliation(s)
- Y Matsuda
- Department of Obstetrics and Gynaecology, Kagoshima Municipal Hospital, Japan
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