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Chaitanya GV, Eeka P, Munker R, Alexander JS, Babu PP. Role of cytotoxic protease granzyme-b in neuronal degeneration during human stroke. Brain Pathol 2011; 21:16-30. [PMID: 20825413 DOI: 10.1111/j.1750-3639.2010.00426.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Infiltration of leukocytes into post-ischemic cerebrum is a well-described phenomenon in stroke injury. Because CD-8(+) T-lymphocytes secrete cytotoxic proteases, including granzyme-b (Gra-b) that exacerbates post-ischemic brain damage, we investigated roles of Gra-b in human stroke. To study the role of Gra-b in stroke, ischemic and non-ischemic tissues (from post-mortem stroke patients) were analyzed using immunoblotting, co-immunoprecipitation, terminal deoxy uridine nick end labeling (TUNEL) and Annexin-V immunostaining, and in vitro neuron survival assays. Activated CG-SH cells and supernatants were used to model leukocyte-dependent injury. Non-ischemic brain tissues were used as non-pathological controls. Non-activated CG-SH cells and supernatants were used as controls for in vitro experiments. Human stroke (ischemic) samples contained significantly higher levels of Gra-b and interferon-gamma inducible protein-10 (IP-10/CXCL10) than non-ischemic controls. In stroke, poly (ADP-ribose) polymerase-1 and heat shock protein-70 were cleaved to canonical proteolytic "signature" fragments by Gra-b. Gra-b was also found to bind to Bid and caspase-3. Gra-b also co-localized with Annexin-V(+) /TUNEL(+) in degenerating neurons. Importantly, Gra-b inhibition protected both normal and ischemia-reperfused neurons against in vitro neurotoxicity mediated by activated CG-SH cells and supernatants. These results suggest that increased leukocyte infiltration and elevated Gra-b levels in the post-stroke brain can induce contact-dependent and independent post-ischemic neuronal death to aggravate stroke injury.
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Affiliation(s)
- Ganta Vijay Chaitanya
- Department of Molecular and Cellular Physiology, School of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, La, USA
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Cell death/proliferation and alterations in glial morphology contribute to changes in diffusivity in the rat hippocampus after hypoxia-ischemia. J Cereb Blood Flow Metab 2011; 31:894-907. [PMID: 20877389 PMCID: PMC3063622 DOI: 10.1038/jcbfm.2010.168] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To understand the structural alterations that underlie early and late changes in hippocampal diffusivity after hypoxia/ischemia (H/I), the changes in apparent diffusion coefficient of water (ADC(W)) were studied in 8-week-old rats after H/I using diffusion-weighted magnetic resonance imaging (DW-MRI). In the hippocampal CA1 region, ADC(W) analyses were performed during 6 months of reperfusion and compared with alterations in cell number/cell-type composition, glial morphology, and extracellular space (ECS) diffusion parameters obtained by the real-time iontophoretic method. In the early phases of reperfusion (1 to 3 days) neuronal cell death, glial proliferation, and developing gliosis were accompanied by an ADC(W) decrease and tortuosity increase. Interestingly, ECS volume fraction was decreased only first day after H/I. In the late phases of reperfusion (starting 1 month after H/I), when the CA1 region consisted mainly of microglia, astrocytes, and NG2-glia with markedly altered morphology, ADC(W), ECS volume fraction and tortuosity were increased. Three-dimensional confocal morphometry revealed enlarged astrocytes and shrunken NG2-glia, and in both the contribution of cell soma/processes to total cell volume was markedly increased/decreased. In summary, the ADC(W) increase in the CA1 region underlain by altered cellular composition and glial morphology suggests that considerable changes in extracellular signal transmission might occur in the late phases of reperfusion after H/I.
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Ancora G, Soffritti S, Lodi R, Tonon C, Grandi S, Locatelli C, Nardi L, Bisacchi N, Testa C, Tani G, Ambrosetto P, Faldella G. A combined a-EEG and MR spectroscopy study in term newborns with hypoxic-ischemic encephalopathy. Brain Dev 2010; 32:835-42. [PMID: 20060251 DOI: 10.1016/j.braindev.2009.11.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 11/02/2009] [Accepted: 11/18/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Brain damage following a perinatal hypoxic-ischemic (HI) insult has been documented by different diagnostic techniques. The aim of the present study was to relate a-EEG time course during the first 24h of life to brain metabolic changes detected by proton MR spectroscopy ((1)H-MRS) at 7-10days of life and to evaluate their correlation with outcome. METHODS Thirty-two patients with any grade HI encephalopathy were studied. Thirty-one out of 32 patients survived and underwent (1)H-MRS examination at 7-10days of life; a-EEG was recorded during the first 24h of life in 27/32 newborns; 26 patients underwent both examinations. Griffiths test, evaluation of motor skills, visual and hearing function were performed at regular intervals until the age of 2years. RESULTS a-EEG at 6, 12 and 24h of life showed a significant correlation with outcome. N-acetyl-aspartate/creatine (Cr), Lactate/Cr and myo-inositol differed significantly between patients with normal or poor outcome. a-EEG time course during the first 24h of life showed improvement in newborns with normal (1)H-MRS and good outcome and a deterioration in those with abnormal (1)H-MRS and poor outcome. CONCLUSIONS a-EEG time course may be able to document the severity and the evolution of the cerebral damage following an HI event. a-EEG is related to the severity of cerebral injury as defined by (1)H-MRS and both examinations showed a good correlation with outcome. These data, obtained in non-cooled infants, may represent reference data for future investigations in cooled infants.
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Affiliation(s)
- Gina Ancora
- Neonatology Unit, Department of Woman, Child and Adolescent Health, University of Bologna, Italy.
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Sanz-Cortés M, Figueras F, Bargalló N, Padilla N, Amat-Roldan I, Gratacós E. Abnormal brain microstructure and metabolism in small-for-gestational-age term fetuses with normal umbilical artery Doppler. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2010; 36:159-165. [PMID: 20549770 DOI: 10.1002/uog.7724] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVES To assess microstructural and metabolic brain differences between small-for-gestational age (SGA) and appropriate-for-gestational age (AGA) fetuses at 37 weeks' gestation by magnetic resonance imaging (MRI) spectroscopy and diffusion weighted imaging. METHODS Eight SGA and five matched AGA singleton fetuses, all with normal umbilical artery Doppler, were evaluated using MRI at 37 weeks to measure markers of brain microstructure and metabolism. The metabolic spectrum of N-acetyl-aspartate/choline, choline/creatine, inositol/choline and creatine/choline ratios in the left frontal lobe and the apparent diffusion coefficient from the right and left basal ganglia and frontal and occipital lobes, pyramidal tract and corpus callosum were analyzed and compared. RESULTS As compared with controls, SGA fetuses showed a significant increase in inositol/choline ratio (SGA, 0.57 vs. AGA, 0.25; P = 0.04) and significantly higher ADC values in the pyramidal tract (SGA, 119.87 x 10(-5) mm(2)/s vs. AGA, 105.11 x 10(-5) mm(2)/s; P = 0.04). CONCLUSIONS SGA fetuses with normal umbilical artery Doppler present microstructural and metabolic brain changes, suggesting the existence of an abnormal in-utero brain development in fetuses with this condition.
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Affiliation(s)
- M Sanz-Cortés
- Maternal-Fetal Medicine Department, Institut Clinic de Ginecologia, Obstetricia i Neonatologia, Hospital Clínic, Barcelona, Spain
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55
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Inder T. Imaging insights of alterations and adaptations in the preterm and late preterm brain. J Pediatr 2010; 156:867-868. [PMID: 20493317 DOI: 10.1016/j.jpeds.2010.04.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 04/05/2010] [Indexed: 10/19/2022]
Affiliation(s)
- Terrie Inder
- Department of Pediatrics, St. Louis Children's Hospital, Washington University, St. Louis, Missouri.
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Bain JM, Ziegler A, Yang Z, Levison SW, Sen E. TGFbeta1 stimulates the over-production of white matter astrocytes from precursors of the "brain marrow" in a rodent model of neonatal encephalopathy. PLoS One 2010; 5:e9567. [PMID: 20221422 PMCID: PMC2832687 DOI: 10.1371/journal.pone.0009567] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 02/10/2010] [Indexed: 12/02/2022] Open
Abstract
Background In children born prematurely and those surviving cerebral ischemia there are white matter abnormalities that correlate with neurological dysfunction. Since this injury occurs in the immature brain, when the majority of subventricular zone (SVZ) cells generate white matter oligodendrocytes, we sought to study the effect this injury has on gliogenesis from the SVZ. We hypothesized that there is aberrant glial cell generation from the SVZ after neonatal hypoxia ischemia (H/I) that contributes to an increased astrogliogenesis with concomitant oligodendroglial insufficiency. Mechanistically we hypothesized that an increase in specific locally produced cytokines during recovery from injury were modifying the differentiation of glial progenitors towards astrocytes at the expense of the more developmentally-appropriate oligodendrocytes. Methodology/Principal Finding For these studies we used the Vannucci H/I rat model where P6 rats are subjected to unilateral common carotid ligation followed by 75 min of systemic hypoxia. Retroviral lineage tracing studies combined with morphological and immunohistochemical analyses revealed the preferential generation of SVZ-derived white matter astrocytes instead of oligodendrocytes post hypoxia/ischemia. Microarray and QRT-PCR analyses of the damaged SVZ showed increased expression of several cytokines and receptors that are known to promote astrocyte differentiation, such as EGF, LIF and TGFß signaling components. Using gliospheres to model the neonatal SVZ, we evaluated the effects of these cytokines on signal transduction pathways regulating astrocyte generation, proliferation and differentiation. These studies demonstrated that combinations of EGF, LIF and TGFß1 reconstituted the increased astrogliogenesis. TGFß1-induced Smad 2/3 phosphorylation and the combination of EGF, LIF and TGFß1 synergistically increased STAT3 phosphorylation over single or double cytokine combinations. Pharmacologically inhibiting ALK5 signaling in vitro antagonized the TGFß1-induced increase in astrocyte generation and antagonizing ALK5 signaling in vivo similarly inhibited astrogliogenesis within the SVZ during recovery from H/I. Conclusion/Significance Altogether, these data indicate that there is aberrant specification of glial precursors within the neonatal SVZ during recovery from neonatal H/I that is a consequence of altered cytokine signaling. Our studies further suggest that antagonizing the ALK5 receptor will restore the normal pattern of cell differentiation after injury to the immature brain.
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Affiliation(s)
- Jennifer M. Bain
- Department of Neurology and Neurosciences, UH Cancer Center and the Graduate School of Biomedical Sciences, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Amber Ziegler
- Department of Neurology and Neurosciences, UH Cancer Center and the Graduate School of Biomedical Sciences, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Zhengang Yang
- Institute of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, People's Republic of China
| | - Steven W. Levison
- Department of Neurology and Neurosciences, UH Cancer Center and the Graduate School of Biomedical Sciences, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
- * E-mail: (SWL); (ES)
| | - Ellora Sen
- National Brain Research Center, Manesar, Haryana, India
- * E-mail: (SWL); (ES)
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58
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The effect of hypoxia on the functional and structural development of the chick brain. Int J Dev Neurosci 2010; 28:343-50. [DOI: 10.1016/j.ijdevneu.2010.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 01/28/2010] [Accepted: 02/10/2010] [Indexed: 12/23/2022] Open
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Abstract
Ocular dominance plasticity (ODP) following monocular deprivation (MD) is a model of activity-dependent neural plasticity that is restricted to an early critical period regulated by maturation of inhibition. Unique developmental plasticity mechanisms may improve outcomes following early brain injury. Our objective was to determine the effects of neonatal cerebral hypoxia-ischemia (HI) on ODP. The rationale extends from observations that neonatal HI results in death of subplate neurons, a transient population known to influence development of inhibition. In rodents subjected to neonatal HI and controls, maps of visual response were derived from optical imaging during the critical period for ODP and changes in the balance of eye-specific response following MD were measured. In controls, MD results in a shift of the ocular dominance index (ODI) from a baseline of 0.15 to -0.10 (p < 0.001). Neonatal HI with moderate cortical injury impairs this shift, ODI = 0.14 (p < 0.01). Plasticity was intact in animals with mild injury and in those exposed to hypoxia alone. Neonatal HI resulted in decreased parvalbumin expression in hemispheres receiving HI compared with hypoxia alone: 23.4 versus 35.0 cells/high-power field (p = 0.01), with no change in other markers of inhibitory or excitatory neurons. Despite abnormal inhibitory neuron phenotype, spontaneous activity of single units and development of orientation selective responses were intact following neonatal HI, while overall visual responses were reduced. Our data suggest that specific plasticity mechanisms are impaired following early brain injury and that the impairment is associated with altered inhibitory neuronal development and cortical activation.
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The encephalopathy of prematurity--brain injury and impaired brain development inextricably intertwined. Semin Pediatr Neurol 2009; 16:167-78. [PMID: 19945651 PMCID: PMC2799246 DOI: 10.1016/j.spen.2009.09.005] [Citation(s) in RCA: 294] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The field of neonatal neurology, and specifically its focus on the premature infant, had its inception in neuropathologic studies. Since then, the development of advanced imaging techniques has guided our developing understanding of the etiology and nature of neonatal brain injury. This review promotes the concept that neonatal brain injury has serious and diverse effects on subsequent brain development, and that these effects likely are more important than simple tissue loss in determining neurologic outcome. Brain injury in the premature infant is best illustrative of this concept. This "encephalopathy of prematurity" is reviewed in the context of the remarkable array of developmental events actively proceeding during the last 16-20 weeks of human gestation. Recent insights into the brain abnormalities in survivors of preterm birth obtained by both advanced magnetic resonance imaging and neuropathologic techniques suggest that this encephalopathy is a complex amalgam of destructive and developmental disturbances. The interrelations between destructive and developmental mechanisms in the genesis of the encephalopathy are emphasized. In the future, advances in neonatal neurology will likely reiterate the dependence of this field on neuropathologic studies, including new cellular and molecular approaches in developmental neurobiology.
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61
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Huang Z, Liu J, Cheung PY, Chen C. Long-term cognitive impairment and myelination deficiency in a rat model of perinatal hypoxic-ischemic brain injury. Brain Res 2009; 1301:100-9. [PMID: 19747899 DOI: 10.1016/j.brainres.2009.09.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Revised: 09/02/2009] [Accepted: 09/03/2009] [Indexed: 01/15/2023]
Abstract
Although periventricular white matter injury is a leading cause of major neurologic disability in premature infants, the relationship between myelination deficiency and long-term cognitive dysfunction is not well understood. The purpose of this study was to investigate oligodendrocytes myelination and long-term spatial cognitive function in rats with perinatal hypoxia-ischemia (HI). Postnatal day 3 (P3) rats were subjected to right carotid artery ligation followed by 2.5 h of hypoxia (6% oxygen). Brain injury during the early and late phases was evaluated by immunostaining at P6 (72 h after the injury) and P47. Spatial cognitive function was evaluated at P42 using the Morris Water Maze test followed by histologic evaluation. HI caused an increase in pre-oligodendrocytes, astrocytes, and microglia in the ipsilateral white matter 72 h after the insult compared to contralateral regions and sham-operated controls (both p<0.05). There were significant decreases in myelin basic protein (MBP)and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase)-labeled oligodendrocytes with glial fibrillary acidic protein (GFAP)-labeled glial scarring in the ipsilateral periventricular white matter at P47 compared to contralateral regions and sham-operated controls (all p<0.05). The rats with HI had spatial learning deficits in navigation trials (longer escape latency and swimming distance) and memory dysfunction in probe trials (fewer number of platform crossings and percentage of time in the target quadrant) compared with sham-operated controls (p<0.05). In this neonatal rat model of HI, myelination deficiency induced by activated astrocytes and microglia during the early phase with subsequent glial scarring was associated with long-term spatial learning and memory dysfunction.
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MESH Headings
- 2',3'-Cyclic-Nucleotide Phosphodiesterases/metabolism
- Analysis of Variance
- Animals
- Animals, Newborn
- Antigens, CD/metabolism
- Antigens, Differentiation, Myelomonocytic/metabolism
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/pathology
- Cell Count
- Cognition Disorders/complications
- Cognition Disorders/metabolism
- Cognition Disorders/pathology
- Cognition Disorders/physiopathology
- Demyelinating Diseases/complications
- Demyelinating Diseases/metabolism
- Demyelinating Diseases/pathology
- Demyelinating Diseases/physiopathology
- Exploratory Behavior/physiology
- Female
- Gliosis/pathology
- Hypoxia-Ischemia, Brain/complications
- Hypoxia-Ischemia, Brain/metabolism
- Hypoxia-Ischemia, Brain/pathology
- Hypoxia-Ischemia, Brain/physiopathology
- Immunohistochemistry
- Male
- Maze Learning/physiology
- Myelin Basic Protein/metabolism
- Nerve Fibers, Myelinated/metabolism
- Nerve Fibers, Myelinated/pathology
- Neuroglia/metabolism
- Neuroglia/pathology
- Rats
- Space Perception/physiology
- Time Factors
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Affiliation(s)
- Zhiheng Huang
- Department of Neonatology, Children's Hospital of Fudan University, Shanghai, China
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62
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Scorza CA, Arida RM, Scorza FA, Cavalheiro EA, Naffah-Mazzacoratti MDG. Nestin down-regulation of cortical radial glia is delayed in rats submitted to recurrent status epilepticus during early postnatal life. ARQUIVOS DE NEURO-PSIQUIATRIA 2009; 67:684-8. [DOI: 10.1590/s0004-282x2009000400020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 05/27/2009] [Indexed: 11/22/2022]
Abstract
OBJECTIVE: Nestin is temporarily expressed in several tissues during development and it is replaced by other protein types during cell differentiation process. This unique property allows distinguishing between undifferentiated and differentiated cells. This study was delineated to analyze the temporal pattern of nestin expression in cortical radial glial cells of rats during normal development and of rats submitted to recurrent status epilepticus (SE) in early postnatal life (P). METHOD: Experimental rats were submitted to pilocarpine-induced SE on P7-9. The cortical temporal profile of nestin was studied by immunohistochemistry at multiple time points (P9, P10, P12, P16, P30 and P90). RESULTS: We observed delayed nestin down-regulation in experimental rats of P9, P10, P12 and P16 groups. In addition, few radial glial cells were still present only in P21 experimental rats. CONCLUSION: Our results suggested that SE during early postnatal life alters normal maturation during a critical period of brain development.
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Pimentel VC, Bellé LP, Pinheiro FV, De Bona KS, Da Luz SCA, Moretto MB. Adenosine deaminase activity, lipid peroxidation and astrocyte responses in the cerebral cortex of rats after neonatal hypoxia ischemia. Int J Dev Neurosci 2009; 27:857-62. [PMID: 19559780 DOI: 10.1016/j.ijdevneu.2009.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/03/2009] [Accepted: 06/17/2009] [Indexed: 10/20/2022] Open
Abstract
Hypoxia ischemia (HI) is a common cause of damage in the fetal and neonatal brain. Lifelong disabilities such as cerebral palsy, epilepsy, behavioral and learning disorders are some of the consequences of brain injury acquired in the perinatal periods. Inflammation and formation of free radicals appear to play key roles in neonatal HI. The aim of this study was to describe the chronological sequence of adenosine deaminase (ADA) activity, the oxidative damage changes and astrocyte response using the classic model of neonatal HI. We observed an increase in the activity of ADA and lipid peroxidation in the cerebral cortex 8 days after neonatal HI. This was accompanied by a GFAP-positive, and the degree of brain damage was determined histochemically by hematoxylin-eosin (HE). Taking into account the important anti-inflammatory role of adenosine, ADA may provide an efficient means for scavenging cell-surrounding adenosine and play an important part in subsequent events of neonatal HI in association with GFAP reactive gliosis. The present investigation showed that neonatal HI causes the increase of free radicals and significant damage in the cerebral cortex. The increase in ADA activity may reflect the activation of the immune system caused by HI because the morphological analysis exhibited a lymphocytic infiltration.
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Affiliation(s)
- V C Pimentel
- Postgraduate Program in Pharmaceutical Sciences, Health Science Centre, Santa Maria, RS, Brazil
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64
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Increased neurogenesis after hypoxic-ischemic encephalopathy in humans is age related. Acta Neuropathol 2009; 117:525-34. [PMID: 19277687 DOI: 10.1007/s00401-009-0509-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 02/01/2009] [Accepted: 02/27/2009] [Indexed: 12/27/2022]
Abstract
The leading cause of morbidity and mortality after successful resuscitation is hypoxic-ischemic encephalopathy (HIE), which results in neuronal loss within the neocortex and the hippocampal formation. This study focuses on the impact of HIE on adult neurogenesis in the human hippocampal dentate gyrus as a potential intrinsic regenerative mechanism in response to neuronal damage. Brain sections of 22 autopsy cases with HIE and of 19 age-matched controls without neuropathological abnormalities were investigated by means of immunohistochemistry. The densities of immature granule cells during axon guidance and outgrowth (assessed by TUC-4 immunohistochemistry) and of young calretinin-expressing postmitotic neurons were increased in the granule cell layer of cases who had suffered from HIE (P = 0.0002 and P = 0.0001, respectively). Similarly, the density of apoptotic granule cells, as detected by in situ tailing and morphological criteria, was increased in HIE (P = 0.014). In cases with HIE, the increase in the density of TUC-4-labeled cells inversely correlated with age (P = 0.027). In contrast, neither the density of proliferating nor that of apoptotic cells was substantially influenced by age within the control group. Taken together, both an increase in adult neurogenesis and in neuronal apoptosis was observed in the human dentate gyrus in response to HIE. The data suggest a decrease of adult neurogenesis in older-aged cases. Whether neurogenesis can contribute to recovery after HIE remains to be determined. The stimulation of adult neurogenesis may be less efficient in older victims of HIE.
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65
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Wang YF, Hatton GI. Astrocytic plasticity and patterned oxytocin neuronal activity: dynamic interactions. J Neurosci 2009; 29:1743-54. [PMID: 19211881 PMCID: PMC3849422 DOI: 10.1523/jneurosci.4669-08.2009] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 11/21/2008] [Accepted: 12/19/2008] [Indexed: 11/21/2022] Open
Abstract
Astroglial-neuronal interactions are important in brain functions. However, roles of glial fibrillary acidic protein (GFAP) in this interaction remain unclear in acute physiological processes. We explored this issue using the supraoptic nucleus (SON) in lactating rats. At first, we identified the essential role of astrocytes in the milk-ejection reflex (MER) by disabling astrocytic functions via intracerebroventricular application of l-aminoadipic acid (l-AAA). l-AAA blocked the MER and reduced GFAP levels in the SON. In brain slices, l-AAA suppressed oxytocin (OT) neuronal activity and EPSCs. Suckling reduced GFAP in immunocytochemical images and in Western blots, reductions that were partially reversed after the MER. OT, the dominant hormone mediating the MER, reduced GFAP expression in brain slices. Tetanus toxin suppressed EPSCs but did not influence OT-reduced GFAP. Protease inhibitors did not influence OT-reduced GFAP images but blocked the degradation of GFAP molecules. In the presence of OT, transient 12 mm K(+) exposure, simulating effects of synchronized bursts before the MER, reversed OT-reduced GFAP expression. Consistently, suckling first reduced and then increased the expression of aquaporin 4, astrocytic water channels coupled to K(+) channels. Moreover, GFAP molecules were associated with astrocytic proteins, including aquaporin 4, actin, and glutamine synthetase and serine racemase. GFAP-aquaporin 4 association decreased during initial suckling and increased after the MER, whereas opposite changes occurred between GFAP and actin. MER also decreased the association between GFAP and glutamine synthetase. These results indicate that suckling elicits dynamic glial neuronal interactions in the SON; GFAP plasticity dynamically reflects OT neuronal activity.
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Affiliation(s)
- Yu-Feng Wang
- Department of Cell Biology and Neuroscience, University of California, Riverside, California 92521, USA.
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66
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Volpe JJ. Brain injury in premature infants: a complex amalgam of destructive and developmental disturbances. Lancet Neurol 2009; 8:110-24. [PMID: 19081519 DOI: 10.1016/s1474-4422(08)70294-1] [Citation(s) in RCA: 1679] [Impact Index Per Article: 111.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Brain injury in premature infants is of enormous public health importance because of the large number of such infants who survive with serious neurodevelopmental disability, including major cognitive deficits and motor disability. This type of brain injury is generally thought to consist primarily of periventricular leukomalacia (PVL), a distinctive form of cerebral white matter injury. Important new work shows that PVL is frequently accompanied by neuronal/axonal disease, affecting the cerebral white matter, thalamus, basal ganglia, cerebral cortex, brain stem, and cerebellum. This constellation of PVL and neuronal/axonal disease is sufficiently distinctive to be termed "encephalopathy of prematurity". The thesis of this Review is that the encephalopathy of prematurity is a complex amalgam of primary destructive disease and secondary maturational and trophic disturbances. This Review integrates the fascinating confluence of new insights into both brain injury and brain development during the human premature period.
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Affiliation(s)
- Joseph J Volpe
- Department of Neurology, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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67
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Chen PH, Cai WQ, Wang LY, Deng QY. A morphological and electrophysiological study on the postnatal development of oligodendrocyte precursor cells in the rat brain. Brain Res 2008; 1243:27-37. [DOI: 10.1016/j.brainres.2008.09.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2008] [Revised: 08/18/2008] [Accepted: 09/10/2008] [Indexed: 12/29/2022]
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68
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Grafe MR. Preface. Int J Dev Neurosci 2008; 26:1. [DOI: 10.1016/j.ijdevneu.2007.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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