Child neurology: a separate and necessary discipline.
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Child↗
Biomedical subjects
Donna M Ferriero
Publications and source records attributed to Donna M Ferriero.
Induction of haem oxygenase-1 causes cortical non-haem iron increase in experimental pneumococcal meningitis: evidence that concomitant ferritin up-regulation prevents iron-induced oxidative damage.
Desferrioxamine inhibits cortical necrosis in neonatal rats with experimental pneumococcal meningitis, suggesting that iron-induced oxidative damage might be responsible for neuronal damage. We therefore examined the spatial and temporal profile of changes in cortical iron and iron homeostatic proteins during pneumococcal meningitis. Infection was associated with a steady and global increase of non-haem iron in the cortex, particularly in neuronal cell bodies of layer II and V, and in capillary endothelial cells. The non-haem iron increase was associated with induction of haem oxygenase (HO)-1 in neurones, microglia and capillary endothelial cells, whereas HO-2 levels remained unchanged, suggesting that the non-haem iron increase might be the result of HO-1-mediated haem degradation. Indeed, treatment with the haem oxygenase inhibitor tin protoporphyrin (which completely blocked the accumulation of bilirubin detected in HO-1-positive cells) completely prevented the infection-associated non-haem iron increase. The same cells also displayed markedly increased ferritin staining, the increase of which occurred independently of HO activity. At the same time, no increase in DNA/RNA oxidation was observed in infected animals (as assessed by in situ detection of 8-hydroxy[deoxy]guanosine), strongly suggesting that ferritin up-regulation protected the brain from iron-induced oxidative damage. Thus, although pneumococcal meningitis leads to an increase of cortical non-haem iron, protective mechanisms up-regulated in parallel prevent iron-induced oxidative damage. Cortical damage does not appear to be a direct consequence of increased iron, therefore.
Animals↗
Candidate gene polymorphisms do not differ between newborns with stroke and normal controls.
BACKGROUND AND PURPOSE: Neonatal stroke is increasingly recognized with an estimated incidence of one in 4000 live births per year. Pathways involved in the pathophysiology of neonatal stroke are diverse and may include thrombosis and thrombolysis, vascular reactivity, and inflammation. METHODS: We compared frequencies of polymorphisms in genes regulating thrombosis and thrombolysis, nitric oxide, cytokines, vascular tone, and cell adhesion in a hospital-based cohort of 59 newborns with stroke relative to a random sample of 437 California newborns. RESULTS: Of the 31 polymorphisms evaluated, no variant allele was significantly more common than the reference allele in newborns with stroke than in the general population. CONCLUSIONS: Using a series of polymorphisms in pathways implicated in the etiology of stroke, newborns with stroke were not distinguished from a normal control group. Further studies are needed to determine the interaction of genetic polymorphisms with environmental risk factors in the pathogenesis of neonatal stroke.
Adolescent↗
Outcomes among newborns with total serum bilirubin levels of 25 mg per deciliter or more.
BACKGROUND: The neurodevelopmental risks associated with high total serum bilirubin levels in newborns are not well defined. METHODS: We identified 140 infants with neonatal total serum bilirubin levels of at least 25 mg per deciliter (428 micromol per liter) and 419 randomly selected controls from a cohort of 106,627 term and near-term infants born from 1995 through 1998 in Kaiser Permanente hospitals in northern California. Data on outcomes were obtained from electronic records, interviews, responses to questionnaires, and neurodevelopmental evaluations that had been performed in a blinded fashion. RESULTS: Peak bilirubin levels were between 25 and 29.9 mg per deciliter (511 micromol per liter) in 130 of the newborns with hyperbilirubinemia and 30 mg per deciliter (513 micromol per liter) or more in 10 newborns; treatment involved phototherapy in 136 cases and exchange transfusion in 5. Follow-up data to the age of at least two years were available for 132 of 140 children with a history of hyperbilirubinemia (94 percent) and 372 of 419 controls (89 percent) and included formal evaluation at a mean (+/-SD) age of 5.1+/-0.12 years for 82 children (59 percent) and 168 children (40 percent), respectively. There were no cases of kernicterus. Neither crude nor adjusted scores on cognitive tests differed significantly between the two groups; on most tests, 95 percent confidence intervals excluded a 3-point (0.2 SD) decrease in adjusted scores in the hyperbilirubinemia group. There was no significant difference between groups in the proportion of children with abnormal neurologic findings on physical examination or with documented diagnoses of neurologic abnormalities. Fourteen of the children with hyperbilirubinemia (17 percent) had "questionable" or abnormal findings on neurologic examination, as compared with 48 controls (29 percent; P=0.05; adjusted odds ratio, 0.47; 95 percent confidence interval, 0.23 to 0.98; P=0.04). The frequencies of parental concern and reported behavioral problems also were not significantly different between the two groups. Within the hyperbilirubinemia group, those with positive direct antiglobulin tests had lower scores on cognitive testing but not more neurologic or behavioral problems. CONCLUSIONS: When treated with phototherapy or exchange transfusion, total serum bilirubin levels in the range included in this study were not associated with adverse neurodevelopmental outcomes in infants born at or near term.
Bilirubin↗
Reduction of caspase-8 and -9 cleavage is associated with increased c-FLIP and increased binding of Apaf-1 and Hsp70 after neonatal hypoxic/ischemic injury in mice overexpressing Hsp70.
BACKGROUND AND PURPOSE: Caspase-8 and caspase-9 are essential proteases of the extrinsic and intrinsic apoptotic pathways, respectively. We investigated whether neuroprotection associated with overexpression of heat-shock protein 70 (Hsp70), a natural cellular antiapoptotic protein, is mediated by caspase-8 and caspase-9 signaling in the neonatal mouse brain after hypoxia/ischemia (H/I) injury. METHODS: Postnatal day 7 transgenic mice overexpressing rat Hsp70 (Hsp70 Tg) and their wild-type (Wt) littermates underwent unilateral common carotid artery ligation followed by 30 minutes of exposure to 8% O2. The expression of apoptotic proteins was quantified by Western blot analysis, and the specific interaction between Hsp70 and apoptotic protease activating factor 1 (Apaf-1) was determined by coimmunoprecipitation. RESULTS: Hsp70 overexpression reduced cytosolic translocation of cytochrome c without affecting the levels of Apaf-1 and pro-caspase-9 24 hours after H/I. The expression of these apoptotic proteins in the naïve neonatal brains was also not affected by Hsp70 overexpression. Reduced caspase-9 cleavage occurred in Hsp70 Tg mice compared with Wt littermates 24 hours after H/I and correlated with increased binding of Hsp70 and Apaf-1. Increased cellular Fas-associated death domain-like interleukin-1beta-converting enzyme inhibitory protein (FLIP) expression and decreased caspase-8 cleavage were also observed in Hsp70 Tg compared with Wt mice 24 hours after H/I. CONCLUSIONS: Our results suggest that the extrinsic and intrinsic apoptotic pathways mediate the neuroprotective effects of Hsp70 overexpression in neonatal H/I, specifically by upregulating FLIP and sequestering Apaf-1, leading to reduced cleavage of caspase-8 and caspase-9.
Animals↗
Hypothermia and perinatal asphyxia: executive summary of the National Institute of Child Health and Human Development workshop.
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Animals↗
Translational stroke research in the developing brain.
Preclinical animal models can help guide the development of clinical pediatric and newborn stroke trials. Data obtained using currently available models of hypoxia-ischemia and focal stroke have demonstrated the need for age-appropriate models. There are age-related differences in susceptibility of the immature brain to oxidative stress and inflammation, as well as in the rate and degree of apoptotic neuronal death. These issues need to be carefully addressed in designing future clinical trials.
Adult↗
Neuroimaging abnormalities in infants with congenital hemiparesis.
Clinical and neuroimaging characteristics of congenital hemiparesis were examined in a retrospective cohort study nested within 199,176 births within the Kaiser Permanente Medical Care Program, 1997-2002. Infants with a physician diagnosis of paresis or cerebral palsy were electronically identified, and charts were reviewed to confirm congenital hemiparesis. A neuroradiologist reviewed available head MRI and CT scans. Of 96 infants with congenital hemiparesis (population prevalence 4.8 per 10,000), 81% received either a head magnetic resonance imaging (n = 55) or head computed tomography only (n = 23). Perinatal arterial infarction was the most common (30%) neuroimaging finding in term infants. Infants with right-sided hemiparesis (relative risk 4.6, 95% confidence interval 1.4-14.4) or moderate to severe weakness (relative risk 4.4, 95% confidence interval 1.1-17.7) were more likely to have had a perinatal arterial infarction. Periventricular white matter lesions predominated in preterm infants (71%). Brain malformations observed in 14 (18%) patients included polymicrogyria, heterotopia, and schizencephaly. The 14 infants (18%) with a normal head imaging study were more likely to outgrow all signs of hemiparesis by age 3 than were infants with an abnormal brain image (29% vs 0%, P < 0.001). Neuroimaging studies provide useful diagnostic and prognostic information in infants with congenital hemiparesis.
Brain↗
Traumatic injury to the immature brain results in progressive neuronal loss, hyperactivity and delayed cognitive impairments.
The immature brain may be particularly vulnerable to injury during critical periods of development. To address the biologic basis for this vulnerability, mice were subjected to traumatic brain injury at postnatal day 21, a time point that approximates that of the toddler-aged child. After motor and cognitive testing at either 2 weeks (juveniles) or 3 months (adults) after injury, animals were euthanized and the brains prepared for quantitative histologic assessment. Brain-injured mice exhibited hyperactivity and age-dependent anxiolysis. Cortical lesion volume and subcortical neuronal loss were greater in brain-injured adults than in juveniles. Importantly, cognitive decline was delayed in onset and coincided with loss of neurons in the hippocampus. Our findings demonstrate that trauma to the developing brain results in a prolonged period of pathogenesis in both cortical and subcortical structures. Behavioral changes are a likely consequence of regional-specific neuronal degeneration.
Aging↗
Can we define the pathogenesis of human periventricular white-matter injury using animal models?
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Animals↗
Acute hypoxia-ischemia results in hydrogen peroxide accumulation in neonatal but not adult mouse brain.
The neonatal brain responds differently to hypoxic-ischemic injury and may be more vulnerable than the mature brain due to a greater susceptibility to oxidative stress. As a measure of oxidative stress, the immature brain should accumulate more hydrogen peroxide (H2O2) than the mature brain after a similar hypoxic-ischemic insult. To test this hypothesis, H2O2 accumulation was measured in postnatal day 7 (P7, neonatal) and P42 (adult) CD1 mouse brain regionally after inducing HI by carotid ligation followed by systemic hypoxia. H2O2 accumulation was quantified at 2, 12, 24, and 120 h after HI using the aminotriazole (AT)-mediated inhibition of catalase spectrophotometric method. Histologic injury was determined by an established scoring system, and infarction volume was determined. P7 and P42 animals were subjected to different durations of hypoxia to create a similar degree of brain injury. Despite similar injury, significantly less H2O2 accumulated in P42 mouse cortex compared with P7 at 2, 12, and 24 h after HI. In addition, less H2O2 accumulated in P42 mouse hippocampus compared with P7 hippocampus at 2 h. Since immature neurons are more vulnerable to the toxic effects of H2O2 than mature neurons, this increased accumulation in the immature brain may explain why the neonatal brain may be more devastated, even after a milder degree of acute hypoxic-ischemic injury.
Acute Disease↗
Quantitative diffusion tensor MRI fiber tractography of sensorimotor white matter development in premature infants.
Diffusion tensor MRI (DTI) fiber tracking is the first non-invasive and in vivo technique for the delineation and quantitation of specific white matter pathways. In this study, quantitative fiber tracking was used to assess the structural development of the motor tract and somatosensory radiation in premature human newborns. These pathways are unmyelinated in the youngest premature infants and begin to myelinate during late preterm maturation. Previous studies have only been able to delineate parts of these pathways that could be manually outlined in 2D based on anatomical landmarks. Furthermore, these previous studies could not separate motor and sensory regions. A high-sensitivity neonatal head coil was employed in conjunction with an MR-compatible incubator to perform high-resolution imaging of the premature infant brain. The motor and somatosensory tracts were successfully delineated with 3D DTI fiber tracking in 37 exams of preterm newborns between 28 and 43 weeks gestational age. Both streamline deterministic and probabilistic methods were employed to perform quantitative fiber tractography. Tract-specific measurements of diffusion parameters including fractional anisotropy, directionally averaged diffusivity, and eigenvalues were obtained from the motor and sensory pathways. Using both deterministic and probabilistic fiber tracking, all tract-specific diffusion parameters were found to be significantly correlated with age and the motor tracts were found to have higher anisotropy and lower diffusivity than the sensory pathway. By segmenting the 3D fiber tracks by slice, measurements from different axial levels of the brain were found to vary with region and age. In summary, deterministic and probabilistic DTI fiber tracking methods were used to quantify the developmental changes of motor and somatosensory pathways in premature infants.
Adult↗
Erythropoietin improves functional and histological outcome in neonatal stroke.
Neonatal stroke is a condition that leads to disability in later life, and as yet there is no effective treatment. Recently, erythropoietin (EPO) has been shown to be cytoprotective following brain injury and may promote neurogenesis. However, the effect of EPO on functional outcome and on morphologic changes in neonatal subventricular zone (SVZ) following experimental neonatal stroke has not been described. We used a transient focal model of neonatal stroke in P10 rat. Injury was documented by diffusion weighted MRI during occlusion. Immediately upon reperfusion, either EPO (5U/gm) or vehicle was administered intraperitoneally and animals were allowed to grow for 2 wk. Sensorimotor function was assessed using the cylinder rearing test and then brains were processed for volumetric analysis of the SVZ. Stroke induced SVZ expansion proportional to hemispheric volume loss. EPO treatment markedly preserved hemispheric volume and decreased the expansion of SVZ unilaterally. Furthermore, EPO treatment significantly improved the asymmetry of forelimb use following neonatal stroke. This functional improvement directly correlated with the amount of preserved hemispheric volume. These results suggest EPO may be a candidate in the treatment of neonatal stroke.
Animals↗
Potential for protection and repair following injury to the developing brain: a role for erythropoietin?
Perinatal brain injury is a major contributor to perinatal morbidity and mortality, and a considerable number of these children will develop long term neurodevelopmental disabilities. Despite the severe clinical and socio-economic significance and the advances in neonatal care over the past twenty years, no therapy yet exists that effectively prevents or ameliorates detrimental neurodevelopmental effects in cases of perinatal/neonatal brain injury. Our objective is to review recent evidence in relation to the pervading hypothesis for targeting time-dependent molecular and cellular repair mechanisms in the developing brain. In addition we review several potential neuroprotective strategies specific to the developing nervous system, with a focus on erythropoietin (Epo) because of its potential role in protection as well as repair.
Animals↗
Selective neuronal vulnerability and inadequate stress response in superoxide dismutase mutant mice.
To understand the role of oxidative stress and mitochondrial defects in the development of neurodegeneration, we examined the age-related pathological changes and corresponding gene expression profiles in homozygous mutant mice deficient in the mitochondrial form of superoxide dismutase (MnSOD, SOD2). These Sod2-/- mice, generated on a B6D2F1 background, developed ataxia at Postnatal Day (P) 11 and progressively deteriorated with frequent seizures by P14. Histopathological examination revealed neurodegenerative changes consistent with the neurological signs. Vacuolar degeneration was observed in neurons and neuropil throughout the brainstem and rostral cortex. The motor trigeminal nucleus in brainstem and the deeper layers of the motor cortex were the earliest regions to degenerate, with the thalamus and hippocampus affected at later stages. Oligonucleotide microarrays were used to compare gene expression profiles in the brainstem and thalamus of Sod2+/+ and -/- mice from birth to P18. Notably, a large set of heat-shock protein genes was transcriptionally down regulated, and this was most likely due to a reduction in the heat-shock transcription factor 1 (HSF1). Other major classes of differentially expressed genes include lipid biosynthesis and ROS metabolism.
Amino Acid Motifs↗
Maternal and infant characteristics associated with perinatal arterial stroke in the infant.
CONTEXT: Perinatal arterial ischemic stroke (PAS) is a common cause of hemiplegic cerebral palsy. Risk factors for this condition have not been clearly defined. OBJECTIVE: To determine maternal and infant characteristics associated with PAS. DESIGN, SETTING, AND PATIENTS: Case-control study nested within the cohort of all 199,176 infants born from 1997 through 2002 in the Kaiser Permanente Medical Care Program, a managed care organization providing care for more than 3 million residents of northern California. Case patients were confirmed by review of brain imaging and medical records (n = 40). Three controls per case were randomly selected from the study population. MAIN OUTCOME MEASURE: Association of maternal and infant complications with risk of PAS. RESULTS: The population prevalence of PAS was 20 per 100,000 live births. The majority (85%) of infants with PAS were delivered at term. The following prepartum and intrapartum factors were more common among case than control infants: primiparity (73% vs 44%, P = .002), fetal heart rate abnormality (46% vs 14%, P<.001), emergency cesarean delivery (35% vs 13%, P = .002), chorioamnionitis (27% vs 11%, P = .03), prolonged rupture of membranes (26% vs 7%, P = .002), prolonged second stage of labor (25% vs 4%, P<.001), vacuum extraction (24% vs 11%, P = .04), cord abnormality (22% vs 6%, P = .01), preeclampsia (19% vs 5%, P = .01), and oligohydramnios (14% vs 3%, P = .01). Risk factors independently associated with PAS on multivariate analysis were history of infertility (odds ratio [OR], 7.5; 95% confidence interval [CI], 1.3-45.0), preeclampsia (OR, 5.3; 95% CI, 1.3-22.0), prolonged rupture of membranes (OR, 3.8; 95% CI, 1.1-12.8), and chorioamnionitis (OR, 3.4; 95% CI, 1.1-10.5). The rate of PAS increased dramatically when multiple risk factors were present. CONCLUSIONS: Perinatal arterial ischemic stroke in infants is associated with several independent maternal risk factors. How these complications, along with their potential effects on the placenta and fetus, may play a role in causing perinatal stroke deserves further study.
Brain↗
Predictors of outcome in perinatal arterial stroke: a population-based study.
Some infants with perinatal arterial ischemic stroke (PAS) experience development of cerebral palsy (CP), epilepsy, and cognitive impairment, whereas others have a normal outcome. Previous prognostic studies rarely have included all diagnosed cases of PAS within a population. Among 199,176 infants born within Kaiser Permanente from 1997 to 2002, we electronically identified head imaging reports and physician diagnoses suggesting stroke. The diagnosis of PAS was confirmed by review of brain imaging and medical records. Presentation of PAS was considered delayed if symptoms were only noted after 28 days. Outcomes were determined by chart review. Of 40 infants with PAS, 36 were observed over 12 months. Abnormal outcomes included CP (58%), epilepsy (39%), language delay (25%), and behavioral abnormalities (22%). A delayed presentation was associated with increased risk for CP (relative risk [RR], 2.2; 95% confidence interval [CI], 1.2-4.2). Radiological predictors of CP included large stroke size (RR, 2.0; 95% CI, 1.2-3.2) and injury to Broca's area (RR, 2.5; 95% CI, 1.3-5.0), internal capsule (RR, 2.2; 95% CI, 1.1-4.4), Wernicke's area (RR, 2.0; 95% CI, 1.1-3.8), or basal ganglia (RR, 1.9; 95% CI, 1.1-3.3). Among infants with PAS, specific radiological findings and a lack of symptoms in the newborn period are associated with increased risk for CP.
Arterial Occlusive Diseases↗
Tractography-based quantitation of diffusion tensor imaging parameters in white matter tracts of preterm newborns.
PURPOSE: To evaluate the feasibility of performing diffusion tensor tractography (DTT) to map and quantify the pyramidal white matter tracts of premature newborns. MATERIALS AND METHODS: Fourteen diffusion tensor MRI (DTI) examinations of nine premature newborns were evaluated. DTT was performed to segment bilateral pyramidal tracts, using a fiber-tracking algorithm originating in the cerebral peduncle (CP) and filtering through the posterior limb of the internal capsule (PLIC) and precentral gyrus (PCG). Voxels containing the resulting tracts were then used for quantitation of DTI parameters along the tract. The DTT-based tract measurements were compared with standard manually placed region-of-interest (ROI) measurements at four locations along the pyramidal tract, and the reproducibility of each technique was evaluated. RESULTS: DTT demonstrated improved reproducibility over manual ROI measurement for pyramidal tract quantitation and was less subject to intra-operator variability (P < 0.0001, Fisher test for equal variance). In general, the anatomic locations and measurements obtained with the two techniques were in good agreement, although some systematic differences were identified in the PLIC and CP. CONCLUSION: Fiber DTT is feasible in premature newborns, provides more reproducible tract measurements than manual ROI methods, and allows quantitation along the entire tract for more detailed DTI assessment of white matter maturation.
Diffusion Magnetic Resonance Imaging↗