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Sökning: L773:0378 5866 OR L773:1421 9859

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1.
  • Ardalan, Maryam, 1979, et al. (författare)
  • Sex-Dependent Gliovascular Interface Abnormality in the Hippocampus following Postnatal Immune Activation in Mice
  • 2022
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 44:4-5, s. 320-330
  • Tidskriftsartikel (refereegranskat)abstract
    • The neuro-gliovascular unit is a crucial structure for providing a balanced well-functioning environment for neurons and their synapses. Activation of the immune system during the developmental period is believed to affect the gliovascular unit, which may trigger neurodevelopmental and neurological/neuropsychiatric diseases. In this study, we hypothesized that vulnerability of the male brain to a neonatal insult was conditioned by sex-dependent differences in the impairment of the hippocampal gliovascular unit. Male and female C57BL/6J pups received lipopolysaccharide (LPS) (1 mg/kg) or saline on postnatal day (P) 5. Brains were collected at P12 and morphological quantifications of hippocampal fibrillary glial acid protein (GFAP(+)) astrocytes and ionized calcium-binding adaptor molecule 1 protein (Iba1+) microglia were performed by using 3-D image analysis together with measuring the length of CD31(+) and aquaporin-4 (AQP4(+)) vessels. We found a significant increase in the length of CD31(+) capillaries in the male LPS group compared to the saline group; however, coverage of capillaries by astrocytic end-feet (AQP4(+)) was significantly reduced. In contrast, there was a significant increase in AQP4(+) capillary length in female pups 1 week after LPS injection. GFAP(+) astrocytes via morphological changes in the hippocampus showed significant enhancement in the activity 1 week following LPS injection in male mice. We propose that neonatal inflammation could induce susceptibility to neurodevelopmental disorders through modification of hippocampal gliovascular interface in a sex-dependent manner.
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2.
  • Baburamani, Ana A, et al. (författare)
  • Does Caspase-6 Have a Role in Perinatal Brain Injury?
  • 2015
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 37:4-5, s. 321-337
  • Tidskriftsartikel (refereegranskat)abstract
    • Apoptotic mechanisms are centre stage for the development of injury in the immature brain, and caspases have been shown to play a pivotal role during brain development and in response to injury. The inhibition of caspases using broad-spectrum agents such as Q-VD-OPh is neuroprotective in the immature brain. Caspase-6, an effector caspase, has been widely researched in neurodevelopmental disorders and found to be important following adult stroke, but its function in the neonatal brain has yet to be detailed. Furthermore, caspases may be important in microglial activation; microglia are required for optimal brain development and following injury, and their close involvement during neuronal cell death suggests that apoptotic cues such as caspase activation may be important in microglial activation. Therefore, in this study we aimed to investigate the possible apoptotic and non-apoptotic functions caspase-6 may have in the immature brain in response to hypoxia-ischaemia. We examined whether caspases are involved in microglial activation. We assessed cleaved caspase-6 expression following hypoxia-ischaemia and conducted primary microglial cultures to assess whether the broad-spectrum inhibitor Q-VD-OPh or caspase-6 gene deletion affected lipopolysaccharide (LPS)-mediated microglial activation and phenotype. We observed cleaved caspase-6 expression to be low but present in the cell body and cell processes in both a human case of white matter injury and 72 h following hypoxia-ischaemia in the rat. Gene deletion of caspase-6 did not affect the outcome of brain injury following mild (50 min) or severe (60 min) hypoxia-ischaemia. Interestingly, we did note that cleaved caspase-6 was co-localised with microglia that were not of apoptotic morphology. We observed that mRNA of a number of caspases was modulated by low-dose LPS stimulation of primary microglia. Q-VD-OPh treatment and caspase-6 gene deletion did not affect microglial activation but modified slightly the M2b phenotype response by changing the time course of SOCS3 expression after LPS administration. Our results suggest that the impact of active caspase-6 in the developing brain is subtle, and we believe there are predominantly other caspases (caspase-2, -3, -8, -9) that are essential for the cell death processes in the immature brain. (C) 2015 S. Karger AG, Basel
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3.
  • Brunse, A, et al. (författare)
  • Brain Barrier Disruption and Region-Specific Neuronal Degeneration during Necrotizing Enterocolitis in Preterm Pigs
  • 2018
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 40:3, s. 198-208
  • Tidskriftsartikel (refereegranskat)abstract
    • Necrotizing enterocolitis (NEC) increases the risk of brain injury and impaired neurodevelopment. Rapid brain maturation prior to birth may explain why preterm brains are particularly vulnerable to serious infections. Using pigs as models, we hypothesized that preterm birth was associated with altered blood-cerebrospinal fluid (CSF) barrier (BCSFB) function and cerebral structural deficits, and that NEC was associated with systemic inflammation, BCSFB disruption, and neuroinflammation. First, cesarean-delivered preterm and term pigs (<i>n</i> = 43–44) were euthanized at birth to investigate BCSFB function and markers of brain structural maturation, or on day 5 to measure markers of blood-brain barrier maturation in the hippocampus and striatum (experiment 1). Next, preterm pigs (<i>n</i> = 162) were fed increasing volumes of infant formula to assess NEC lesions, systemic inflammation, BCSFB permeability, cerebral histopathology, hippocampal micro­glial density, and cytokine levels on day 5 (experiments 2 and 3). In experiment 1, preterm newborns had increased CSF-plasma ratios of albumin and raffinose, reduced CSF glucose levels, as well as increased cerebral hydration and reduced white matter myelination compared with term animals. We observed lower hippocampal (but not striatal) perivascular astrocyte coverage for the first 5 days after preterm birth, accompanied by altered cell junction protein levels. In experiments 2 and– 3, piglets with severe NEC lesions showed reduced blood thrombocytes and increased plasma C-reactive protein and interleukin-6 levels. NEC was associated with increased CSF-plasma albumin and raffinose ratios, reduced CSF leukocyte numbers, and increased cerebral hydration. In the hippocampus, NEC was associated with pyramidal neuron loss and increased interleukin-6 levels. In the short term, NEC did not affect cerebral myelination or microglia density. In conclusion, altered BCSFB properties and brain structural deficits were observed in pigs after preterm birth. Acute gastrointestinal NEC lesions were associated with systemic inflammation, increased BCSFB permeability and region-specific neuronal damage. The results demonstrate the importance of early interventions against NEC to prevent brain injury in preterm infants.
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4.
  • Cabanes, A, et al. (författare)
  • Maternal high n-6 polyunsaturated fatty acid intake during pregnancy increases voluntary alcohol intake and hypothalamic estrogen receptor alpha and beta levels among female offspring
  • 2000
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 22:5-6, s. 488-493
  • Tidskriftsartikel (refereegranskat)abstract
    • Identification of nongenetic biological factors that predispose to alcohol abuse is central to attempts to prevent alcoholism. Since an exposure to estradiol in utero increases voluntary alcohol intake in adulthood, we investigated whether an increase in pregnancy estradiol levels, caused by feeding pregnant mice a high-fat corn oil diet, also influences voluntary alcohol intake among female offspring. In addition, the effect on estrogen receptor α (ER-α) and ER-β protein levels in the brain using Western blot assay, was determined. Pregnant CD-1 mice were kept on a high n-6 polyunsaturated fatty acid (PUFA; 43% calories from corn oil) or low n-6 PUFA diet (16% calories from corn oil) throughout gestation, and switched to a Purina laboratory chow after the pups were born. When 4 months of age, the female offspring were given a choice between 5% alcohol and tap water. The offspring of high n-6 PUFA mothers voluntarily consumed more alcohol than the offspring of low n-6 PUFA mothers. ER-α and ER-β protein levels in the hypothalamus were 1.5- and 2-fold higher, respectively, in the female offspring of high n-6 PUFA mothers than in the low n-6 PUFA offspring. No significant changes in the protein levels of ER-α and ER-β were seen in the frontal brain. Our findings indicate that a maternal exposure to a high n-6 PUFA diet during pregnancy increases alcohol intake among female offspring. This behavioral change, together with previously observed increase in aggressiveness and reduction in depressive-like behavior in these offspring, may be linked to an increase in the hypothalamic ER-α and ER-β levels.
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5.
  • Carlsson, Ylva, 1975, et al. (författare)
  • Role of mixed lineage kinase inhibition in neonatal hypoxia-ischemia.
  • 2009
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 31:5, s. 420-6
  • Tidskriftsartikel (refereegranskat)abstract
    • Hypoxic-ischemic brain injury is often delayed and involves both apoptotic and immunoregulatory mechanisms. In this study, we used a neonatal model of hypoxia-ischemia to examine the effect of the mixed lineage kinase (MLK) inhibitor CEP-1347 on brain damage, apoptosis and inflammation. The tissue volume loss was reduced by 28% (p = 0.019) in CEP-1347-treated versus vehicle-treated rats and CEP-1347 significantly attenuated microgliosis at 7 days (p = 0.038). CEP-1347 decreased TUNEL-positive staining as well as cleaved caspase 3 immunoreactivity. CEP-1347 did not affect the expression of pro-inflammatory cytokines IL-1 beta, IL-6 and MCP-1, nor did it affect the expression of OX-42 (CR3) and OX-18 (MHC I) 24 h after the insult. In conclusion, the MLK inhibitor CEP-1347 has protective effects in a neonatal rat model of hypoxia-ischemia, which is mainly related to reduced apoptosis.
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6.
  • Dean, J. M., et al. (författare)
  • A Critical Review of Models of Perinatal Infection
  • 2015
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 37:4-5, s. 289-304
  • Forskningsöversikt (refereegranskat)abstract
    • One of the central, unanswered questions in perinatology is why preterm infants continue to have such poor long-term neurodevelopmental, cognitive and learning outcomes, even though severe brain injury is now rare. There is now strong clinical evidence that one factor underlying disability may be infection, as well as nonspecific inflammation, during fetal and early postnatal life. In this review, we examine the experimental evidence linking both acute and chronic infection/inflammation with perinatal brain injury and consider key experimental determinants, including the microglia response, relative brain and immune maturity and the pattern of exposure to infection. We highlight the importance of the origin and derivation of the bacterial cell wall component lipopolysaccharide. Such experimental paradigms are essential to determine the precise time course of the inflammatory reaction and to design targeted neuroprotective strategies to protect the perinatal brain from infection and inflammation. (C) 2015 S. Karger AG, Basel
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7.
  • Dudink, I., et al. (författare)
  • An Optimized and Detailed Step-by-Step Protocol for the Analysis of Neuronal Morphology in Golgi-Stained Fetal Sheep Brain
  • 2022
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 44:4-5, s. 344-362
  • Tidskriftsartikel (refereegranskat)abstract
    • Antenatal brain development during the final trimester of human pregnancy is a time when mature neurons become increasingly complex in morphology, through axonal and dendritic outgrowth, dendritic branching, and synaptogenesis, together with myelin production. Characterizing neuronal morphological development over time is of interest to developmental neuroscience and provides the framework to measure gray matter pathology in pregnancy compromise. Neuronal microstructure can be assessed with Golgi staining, which selectively stains a small percentage (1-3%) of neurons and their entire dendritic arbor. Advanced imaging processing and analysis tools can then be employed to quantitate neuronal cytoarchitecture. Traditional Golgi-staining protocols have been optimized, and commercial kits are readily available offering improved speed and sensitivity of Golgi staining to produce consistent results. Golgi-stained tissue is then visualized under light microscopy and image analysis may be completed with several software programs for morphological analysis of neurons, including freeware and commercial products. Each program requires optimization, whether semiautomated or automated, requiring different levels of investigator intervention and interpretation, which is a critical consideration for unbiased analysis. Detailed protocols for fetal ovine brain tissue are lacking, and therefore, we provide a step-by-step workflow of computer software analysis for morphometric quantification of Golgi-stained neurons. Here, we utilized the commonly applied FD Rapid GolgiStain kit (FD NeuroTechnologies) on ovine fetal brains collected at 127 days (0.85) of gestational age for the analysis of CA1 pyramidal neurons in the hippocampus. We describe the step-by-step protocol to retrieve neuronal morphometrics using Imaris imaging software to provide quantification of apical and basal dendrites for measures of dendrite length (mu m), branch number, branch order, and Sholl analysis (intersections over radius). We also detail software add-ons for data retrieval of dendritic spines including the number of spines, spine density, and spine classification, which are critical indicators of synaptic function. The assessment of neuronal morphology in the developing brain using Rapid-Golgi and Imaris software is labor-intensive, particularly during the optimization period. The methodology described in this step-by-step description is novel, detailed, and aims to provide a reproducible, working protocol to quantify neuronal cytoarchitecture with simple descriptions that will save time for the next users of these commonly used techniques.
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8.
  • Engelsberg, Karl, et al. (författare)
  • Human Retinal Development in an in situ Whole Eye Culture System.
  • 2011
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 33, s. 110-117
  • Tidskriftsartikel (refereegranskat)abstract
    • Phenotypic characterization of human retinogenesis may be facilitated by use of the tissue culture system paradigm. Traditionally, most culture protocols involve isolation of retinal tissue and/or cells, imposing various degrees of trauma, which in many cases leads to abnormal development. In this paper, we present a novel culture technique using whole embryonic eyes to investigate whether the retina in situ can develop normally in vitro. All procedures were carried out in accordance with the Declaration of Helsinki. Human embryos were obtained from elective abortions with the informed consent of the women seeking abortion. A total of 19 eyes were enucleated. The ages of the embryonic retinas were 6-7.5 weeks. Eyecups from 2 eyes were fixed immediately, to be used as controls. The remaining 17 eyes were placed on culture plates and divided into 3 groups kept for 7 (n = 4), 14 (n = 7) and 28 (n = 6) days in vitro (DIV). After fixation, the specimens were processed for hematoxylin and eosin staining, immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Antibodies against recoverin (rods and cones), protein kinase C (PKC; rod bipolar cells) and vimentin (Müller cells) were used. TUNEL was used to detect apoptotic cells. In hematoxylin- and eosin-stained sections, the control retinas displayed a neuroblast cell layer (NBL) and an inner marginal zone. Specimens kept 7-14 DIV had a similar appearance, while 28-day specimens consisted of an NBL with almost no marginal zone. Thirteen of the 17 cultured retinas displayed completely normal lamination without rosettes or double folds. Pyknotic cells were found at the inner margin of the retinas, and the proportion of these cells increased with time in vitro. TUNEL staining revealed a few scattered cells in 7-DIV specimens, and the amount of stained cells in the inner part of the retinas progressively increased in 14- and 28-DIV specimens. Vimentin labeling showed cells arranged in a vertical pattern in all retinas. Labeling with recoverin revealed photoreceptors in 4 of the retinas kept for 14 DIV, and in all retinas kept for 28 DIV. After 28 DIV, 2 of the eyes labeled with PKC contained rod bipolar cells with minimal axons. Here we showed that human embryonic retinas can be kept in culture in situ within the eye for at least 4 weeks. Abnormal lamination is not as frequent as in isolated full-thickness retinas, indicating that physical and biochemical contact with surrounding tissues is vital for proper development. Several types of the retina-specific neuronal and glial cells were seen to differentiate according to the in vivo schedule. The results are important for future studies of retinal development, and the technique can also be used for testing the effects of various drugs on the immature retina.
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9.
  • Fleiss, Bobbi, et al. (författare)
  • The Anti-Inflammatory Effects of the Small Molecule Pifithrin-µ on BV2 Microglia.
  • 2015
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 37:(4-5), s. 363-75
  • Tidskriftsartikel (refereegranskat)abstract
    • Neonatal encephalopathy (NE) is a leading cause of childhood death and disability in term infants. Treatment options for perinatal brain injury are limited and developing therapies that target multiple pathways within the pathophysiology of NE are of great interest. Pifithrin-µ (PFT-µ) is a drug with striking neuroprotective abilities in a preclinical model of hypoxia-ischemia (HI)-induced NE wherein cell death is a substantial cause of injury. Work from neurons and tumor cells reports that PFT-µ is able to inhibit p53 binding to the mitochondria, heat shock protein (HSP)-70 substrate binding and activation of the NF-kB pathway. The purpose of this study is to understand whether the neuroprotective effects of PFT-µ also include direct effects on microglia. We utilized the microglial cell line, BV2, and we studied the dose-dependent effect of PFT-µ on M1-like and M2-like phenotype using qRT-PCR and Western blotting, including the requirement for the presence of p53 or HSP-70 in these effects. We also assessed phagocytosis and the effects of PFT-µ on genes within metabolic pathways related to phenotype. We noted that PFT-µ robustly reduced the M1-like (lipopolysaccharide, LPS-induced) BV2 response, spared the LPS-induced phagocytic ability of BV2 and had no effect on the genes related to metabolism and that effects on phenotype were partially dependent on the presence of HSP-70 but not p53. This study demonstrates that the neuroprotective effects of PFT-µ in HI-induced NE may include an anti-inflammatory effect on microglia and adds to the evidence that this drug might be of clinical interest for the treatment of NE. © 2015 S. Karger AG, Basel.
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10.
  • Galinsky, R., et al. (författare)
  • Magnesium Is Not Consistently Neuroprotective for Perinatal Hypoxia-Ischemia in Term-Equivalent Models in Preclinical Studies: A Systematic Review
  • 2014
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 36:2, s. 73-82
  • Tidskriftsartikel (refereegranskat)abstract
    • There is an important unmet need to further improve the outcome of neonatal encephalopathy in term infants. Meta-analyses of large controlled trials now suggest that maternal magnesium sulfate (MgSO4) therapy is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth, but that it has no effect on death or disability. Because of this inconsistency, it remains controversial whether MgSO4 is clinically neuroprotective and, thus, it is unclear whether it would be appropriate to test MgSO4 for treatment of encephalopathy in term infants. We therefore systematically reviewed the preclinical evidence for neuroprotection with MgSO4 before or after hypoxic-ischemic encephalopathy (HIE) in term-equivalent perinatal and adult animals. The outcomes were highly inconsistent between studies. Although there were differences in dose and timing of administration, there was evidence that beneficial effects of MgSO4 were associated with confounding mild hypothermia and, strikingly, the studies that included rigorous maintenance of environmental temperature or body temperature consistently suggested a lack of effect. On balance, these preclinical studies suggest that peripherally administered MgSO4 is unlikely to be neuroprotective. Rigorous testing in translational animal models of perinatal HIE is needed before MgSO4 should be considered in clinical trials for encephalopathy in term infants. (C) 2014 S. Karger AG, Basel
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11.
  • Ghosh, Fredrik, et al. (författare)
  • Cell Type Differentiation Dynamics in the Developing Porcine Retina.
  • 2010
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 32, s. 47-58
  • Tidskriftsartikel (refereegranskat)abstract
    • The dynamics of retinal embryogenesis have been well characterized previously in terms of cell proliferation, genesis and migration, whereas overall cell type differentiation within the retinal layers has been less thoroughly explored. In the present study, phenotypical differentiation of all 7 major retinal cell types was examined in the developing porcine retina using one cell-specific immunohistochemical marker per cell type. At the end of the first trimester at E39 (39 days after gestation), neurofilament labeled ganglion cells, recoverin labeled photoreceptors, vimentin labeled Müller cells and synaptophysin labeled presynaptic vesicles were found. Rhodopsin labeled rod photoreceptors were present at E60, whereas cone transducin labeled cone photoreceptors were not seen until E99. Differentiation of inner nuclear cells coincided with the appearance of the retinal layers at E70-E99 with the presence of parvalbumin labeled amacrine cells, calbindin labeled horizontal cells and PKC labeled rod bipolar cells. At postnatal day 4, all retinal subtypes except for cone photoreceptors displayed a labeling pattern corresponding to the one found in the adult porcine retina. The immunohistochemical labeling pattern suggests that phenotypic differentiation of the 7 principal retinal cell types in the porcine retina follows a central-to-peripheral spatio-temporal gradient similar to the one reported for cell proliferation and genesis. Differentiation of the non-laminated retinal cell mass appears to be initiated at its outer and inner margins and progresses inwards, a process which ends in the formation of the characteristic plexiform and nuclear layers. The dynamics of retinal cell type differentiation are of interest from a biological standpoint and are also important for therapeutical strategies in retinal degenerative disease.
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12.
  • Ghosh, Fredrik, et al. (författare)
  • Exogenous Glutamate Modulates Porcine Retinal Development in vitro.
  • 2012
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866.
  • Tidskriftsartikel (refereegranskat)abstract
    • Embryogenesis of the retina is a complex event orchestrated by a multitude of physical and biochemical signals. To study the impact of intrinsic developmental cues, the retinal tissue can be isolated in culture which also enables modulation of normal development for other purposes, i.e. transplantation of specific neuronal cell types. In the present experiment, cell type development of immature porcine retinal tissue kept in culture was explored using specific immunohistochemical markers. Retinal explants were either kept under standard culture conditions or supplemented with glutamate and their morphology was compared with in vivo controls of corresponding age. After 15 days in vitro (DIV), E45 retinal explants displayed several signs of atypical development when compared with E60 in vivo controls. First, an accelerated photoreceptor differentiation was evident, seen in sections labeled with antibodies directed against recoverin, rhodopsin and synaptophysin. Second, apoptotic cells in the inner retina were more prevalent in the cultured retinas (TUNEL). Rod photoreceptor differentiation as well as inner retinal apoptosis was even more pronounced in glutamate-supplemented specimens in which they occurred already at 8 DIV. Müller cell, vimentin and GFAP expression was not affected in any of the cultured retinas. These results suggest that normal retinal embryogenesis is more dependent on tissue extrinsic factors than what has been deduced from previous small animal experiments. Glutamate, which has been identified as an important regulator of cell cycle exit, may also be important for photoreceptor differentiation and induction of developmental apoptosis. Insights into retinal cell type differentiation under in vitro conditions is of interest from a biological standpoint, and the possibility of modulation of this process is valuable for research directed towards cell replacement in retinal degenerative disease.
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13.
  • Gorman, AM, et al. (författare)
  • Role of mitochondria in neuronal apoptosis
  • 2000
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 22:5-6, s. 348-358
  • Tidskriftsartikel (refereegranskat)abstract
    • Apoptosis is a controlled form of cell death that participates in the demise of neuronal cells during development, neurodegenerative disorders and exposure to neurotoxic agents. In recent years, the mitochondria have emerged as being pivotal in controlling apoptosis. They house a number of apoptogenic molecules that are released into the cytoplasm at the onset of apoptosis. These include cytochrome c, apoptosis-inducing factor and various caspases. Mitochondria also play an important role in intracellular Ca<sup>2+</sup> regulation, which is crucial to excitotoxic neurodegeneration. Alterations in energy (ATP) production by mitochondria (due to hypoxia or mutations in genes encoding mitochondrial proteins of the electron transport chain) can induce apoptosis in neurons or increase their sensitivity to apoptosis.
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14.
  • Gram, Magnus, et al. (författare)
  • Insulin-Like Growth Factor 1 in the Preterm Rabbit Pup: Characterization of Cerebrovascular Maturation following Administration of Recombinant Human Insulin-Like Growth Factor 1/Insulin-Like Growth Factor 1-Binding Protein 3
  • 2021
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 43:5, s. 281-295
  • Tidskriftsartikel (refereegranskat)abstract
    • Following preterm birth, serum levels of insulin-like growth factor 1 (IGF-1) decrease compared to corresponding in utero levels. A recent clinical trial indicated that supplementation with recombinant human (rh) IGF-1/rhIGF-binding protein 3 (rhIGF-1/rhIGFBP-3) prevents severe intraventricular hemorrhage (IVH) in extremely preterm infants. In a preterm rabbit pup model, we characterized endogenous serum and hepatic IGF-1, along with brain distribution of IGF-1 and IGF-1 receptor (IGF1R). We then evaluated the effects of rhIGF-1/rhIGFBP-3 on gene expression of regulators of cerebrovascular maturation and structure. Similar to preterm infants, serum IGF-1 concentrations decreased rapidly after preterm birth in the rabbit pup. Administration of rhIGF-1/rhIGFBP-3 restored in utero serum levels but was rapidly eliminated. Immunolabeled IGF1R was widely distributed in multiple brain regions, displaying an abundant density in the choroid plexus and sub-ependymal germinal zones. Increased IGF-1 immunoreactivity, distributed as IGF1R, was detected 4 h after rhIGF-1/rhIGFBP-3 administration. The rhIGF-1/rhIGFBP-3 treatment led to upregulation of choroid plexus genes involved in vascular maturation and structure, with corresponding protein translation for most of these genes. The preterm rabbit pup model is well suited for evaluation of IGF-1-based prevention of IVH. Administration of rhIGF-1/rhIGFBP-3 affects cerebrovascular maturation, suggesting a role for it in preventing preterm IVH.
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15.
  • Gressens, Pierre, et al. (författare)
  • Pitfalls in the Quest of Neuroprotectants for the Perinatal Brain.
  • 2011
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 33:3-4, s. 189-198
  • Tidskriftsartikel (refereegranskat)abstract
    • Sick preterm and term newborns are highly vulnerable to neural injury, and thus there has been a major search for new, safe and efficacious neuroprotective interventions in recent decades. Preclinical studies are essential to select candidate drugs for clinical trials in humans. This article focuses on 'negative' preclinical studies, i.e. studies where significant differences cannot be detected. Such findings are critical to inform both clinical and preclinical investigators, but historically they have been difficult to publish. A significant amount of time and resources is lost when negative results or nonpromising therapeutics are replicated in separate laboratories because these negative results were not shared with the research community in an open and accessible format. In this article, we discuss approaches to strengthen conclusions from negative preclinical studies and, conversely, to reduce false-negative preclinical evaluations of potential therapeutic compounds. Without being exhaustive, we address three major issues in conducting and interpreting preclinical experiments, including: (a) the choice of animal models, (b) the experimental design, and (c) issues concerning statistical analyses of the experiments. This general introduction is followed by synopses of negative data obtained from studies of three potential therapeutics for perinatal brain injury: (1) the somatostatin analog octreotide, (2) an AMPA/kainate receptor antagonist, topiramate, and (3) a pyruvate derivative, ethyl pyruvate.
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16.
  • Han, Wei, et al. (författare)
  • Delayed, Long-Term Administration of the Caspase Inhibitor Q-VD-OPh Reduced Brain Injury Induced by Neonatal Hypoxia-Ischemia.
  • 2014
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 36:1, s. 64-72
  • Tidskriftsartikel (refereegranskat)abstract
    • Apoptosis contributes greatly to the morphological and biochemical features of cell death after neonatal cerebral hypoxia-ischemia (HI), making this mode of cell death a promising therapeutic target. We previously showed that 10 mg/kg of the caspase inhibitor Q-VD-OPh at the onset of and immediately after HI on postnatal day 9 reduced brain infarct volume. In this study, delayed administration of Q-VD-OPh, 12 and 36 h after HI, decreased HI-induced caspase-3 activity (DEVD cleavage) by 23% and diminished the levels of the proinflammatory chemokines CCL2 (MCP-1) and CCL3 (MIP-1α) by 29.3 and 29.1%, respectively, but not the levels of the anti-inflammatory cytokines IL-4 and IL-10. Long-term administration of Q-VD-OPh initiated at 12 h after HI, and continued at 24-hour intervals for 2 weeks, reduced total brain tissue loss by 31.3% from 41.5 ± 3.1 mm(3) in the vehicle group to 28.5 ± 3.0 mm(3) in the Q-VD-OPh group when evaluated 16 weeks after HI (p = 0.004). Q-VD-OPh treatment also ameliorated the loss of sensorimotor function, as evaluated by a cylinder rearing test (Q-VD-OPh: 30.8 ± 4.3% vs. vehicle: 59.7 ± 6.3% in nonimpaired forepaw preference) 3 weeks after HI, and reduced HI-induced hyperactivity, as measured in an open field test (Q-VD-OPh: 4,062 ± 198 cm vs. vehicle: 4,792 ± 205 cm in distance moved) 7 weeks after the insult. However, the functional protection was no longer observed when analyzed again at later time points. The mechanisms underlying the discrepancy between sustained morphological protection and transient functional protection remain to be elucidated. © 2014 S. Karger AG, Basel.
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17.
  • Hansson, EM, et al. (författare)
  • Recording Notch signaling in real time
  • 2006
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 28:1-2, s. 118-127
  • Tidskriftsartikel (refereegranskat)abstract
    • Notch signaling is a highly conserved signaling pathway, which is critical for many cell fate decisions. Ligand activation of Notch leads to cleavage of the Notch receptor and liberation of the Notch intracellular domain (ICD) from the membrane-tethered receptor. After translocation to the nucleus, the Notch ICD interacts with the DNA-binding protein CSL to activate gene transcription. To better understand the temporal and spatial aspects of Notch signaling, we here describe a fluorescent protein-based reporter assay that allows Notch activation to be followed in real time in individual cells. We have generated a reporter construct composed of 12 CSL-binding motifs linked to fluorescent proteins with different half-lives: a stabler red fluorescent protein (DsRedExpressDR) and a destabilized form of green fluorescent protein (d1EGFP). The fluorescent reporters reflect the activation status of Notch signaling with single-cell resolution. The reporters rapidly respond to various forms of Notch activation, including ligand activation of full-length Notch receptors. Finally, we use this assay to gain insights into the level of Notch signaling in CNS progenitor cells in culture and in vivo.
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18.
  • Hattori, T, et al. (författare)
  • Administration of umbilical cord blood cells transiently decreased hypoxic-ischemic brain injury in neonatal rats
  • 2015
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 37:2, s. 95-104
  • Tidskriftsartikel (refereegranskat)abstract
    • This study aimed to investigate whether the administration of mononuclear cells derived from human umbilical cord blood cells (UCBCs) could ameliorate hypoxic-ischemic brain injury in a neonatal rat model. The left carotid arteries of 7-day-old rats were ligated, and the rats were then exposed to 8% oxygen for 60 min. Mononuclear cells derived from UCBCs using the Ficoll-Hypaque technique were injected intraperitoneally 6 h after the insult (1.0 × 10<sup>7</sup> cells). Twenty-four hours after the insult, the number of cells positive for the oxidative stress markers 4-hydroxy-2-nonenal and nitrotyrosine, in the dentate gyrus of the hippocampus in the UCBC-treated group, decreased by 36 and 42%, respectively, compared with those in the control group. In addition, the number of cells positive for the apoptosis markers active caspase-3 and apoptosis-inducing factor decreased by 53 and 58%, respectively. The number of activated microglia (ED1-positive cells) was 51% lower in the UCBC group compared with the control group. In a gait analysis performed 2 weeks after the insult, there were no significant differences among the sham-operated, control and UCBC groups. An active avoidance test using a shuttle box the following week also revealed no significant differences among the groups. Neither the volumes of the hippocampi, corpus callosum and cortices nor the numbers of neurons in the hippocampus were different between the UCBC and control groups. In summary, a single intraperitoneal injection of UCBC-derived mononuclear cells 6 h after an ischemic insult was associated with a transient reduction in numbers of apoptosis and oxidative stress marker-positive cells, but it did not induce long-term morphological or functional protection. Repeated administration or a combination treatment may be required to achieve sustained protection.
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19.
  • Jungner, Åsa, et al. (författare)
  • White Matter Brain Development after Exposure to Circulating Cell-Free Hemoglobin and Hyperoxia in a Rat Pup Model
  • 2020
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 41:3-4, s. 234-246
  • Tidskriftsartikel (refereegranskat)abstract
    • Neonates born with critical congenital heart defects are at risk of diffuse white matter injuries and neurodevelopmental impairments. This study aimed to determine the impact of circulating cell-free hemoglobin and hyperoxia, both present during cardiopulmonary bypass circulation, on white matter brain development. Postnatal day 6 rat pups were injected intraperitoneally with cell-free Hb or vehicle and exposed to hyperoxia (fiO2 = 0.8) or normoxia (fiO2 = 0.21) for 24 h. We evaluated apoptosis, myelination, and oligodendrocyte maturation with immunohistochemistry, gene and protein analyses, and in vivo diffusion tensor magnetic resonance imaging (MRI). Consistent with previous studies, we found an increase in apoptosis of oligodendrocytes as determined by TUNEL+ staining in Olig2+ cells in white matter, cortex, thalamus, and hippocampus following exposure to hyperoxia with no additional effect of cell-free Hb. A transient increase in the mRNA expression of intercellular adhesion molecule 1 at 6 h was observed following combined exposure to cell-free Hb and hyperoxia. No indications of oligodendrocyte maturational delay or hypomyelination were observed after either insult, delivered separately or combined, as determined by immunohistochemistry, Western blot, and diffusion tensor MRI. In our model, exposure to circulatory cell-free Hb, with or without concomitant hyperoxia, did not significantly alter brain white matter development.
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20.
  • Järlestedt, Katarina, et al. (författare)
  • Trace Fear Conditioning Detects Hypoxic-Ischemic Brain Injury in Neonatal Mice.
  • 2011
  • Ingår i: Developmental neuroscience. - Basel : S. Karger AG. - 1421-9859 .- 0378-5866. ; 33:3-4, s. 222-230
  • Tidskriftsartikel (refereegranskat)abstract
    • Trace fear conditioning is a well-established test for the assessment of learning deficits in rodents. The aim of this study was to determine whether hypoxia-ischemia (HI) on postnatal day 9 (P9) in mice prevents the acquisition and expression of cued and contextual fear learning in early adulthood. Brain injury was induced in mice on P9 by 30 min of HI. On P49 and P50, animals were tested for: (1) trace fear conditioning with a short delay (2 s) between a shock-paired tone plus light and shock, (2) trace fear conditioning with a longer delay (20 s) between a shock-paired tone and shock, and (3) trace fear conditioning with a 2-second delay between a shock-paired tone and shock with additional visual, olfactory and tactile contextual cues in the fear conditioning apparatus. Outcome was assessed as percent of time spent freezing during a 2-min test. Histological assessment of the hippocampus and amygdala was performed on P51 to determine the extent of HI injury. Both shock-paired tone plus light with a short delay and shock-paired tone with a short delay plus additional contextual cues enhanced tone-induced freezing behavior in a nonhandled control group, but not in the HI group. For trace fear conditioning with a 20-second delay between the tone and the shock, freezing behavior did not differ significantly between nonhandled control and HI animals. Dorsal hippocampal and amygdala volumes were smaller in the ischemic hemispheres of the HI mice that displayed impaired fear memory with shock-paired tone plus light. In summary, we have shown that trace fear conditioning is a sensitive method for detecting memory impairments in adolescent mice following mild HI injury during the neonatal period. Combining a discrete conditioned stimulus (shock-paired tone plus light) with a short trace delay was the most sensitive method for using the fear conditioning paradigm to detect mild HI damage to the hippocampus and amygdala.
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21.
  • Kichev, A., et al. (författare)
  • Implicating Receptor Activator of NF-kappa B (RANK)/RANK Ligand Signalling in Microglial Responses to Toll-Like Receptor Stimuli
  • 2017
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 39:1-4, s. 192-206
  • Tidskriftsartikel (refereegranskat)abstract
    • Inflammation in the perinatal brain caused by maternal or intrauterine fetal infection is now well established as an important contributor to the development of perinatal brain injury. Exposure to inflammatory products can impair perinatal brain development and act as a risk factor for neurological dysfunction, cognitive disorders, cerebral palsy, or preterm birth. Pre-exposure to inflammation significantly exacerbates brain injury caused by hypoxic/ischaemic insult. Tumour necrosis factor (TNF) is a family of cytokines largely involved in inflammation signalling. In our previous study, we identified the importance of TNF-related apoptosis-inducing ligand (TRAIL) signalling in the development of perinatal brain injury. We observed a significant increase in the expression levels of a soluble decoy receptor for TRAIL, osteoprotegerin (OPG). Besides TRAIL, OPG is able to bind the receptor activator of the NF-kappa B (RANK) ligand (RANKL) and inhibit its signalling. The function of the RANK/RANKL/OPG system in the brain has not come under much scrutiny. The aim of this research study was to elucidate the role of RANK, RANKL, and OPG in microglial responses to the pro-inflammatory stimuli lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (Poly I: C). Here, we show that RANK signalling is important for regulating the activation of the BV2 microglial cell line. We found that LPS treatment causes a significant decrease in the expression of RANK in the BV2 cell line while significantly increasing the expression of OPG, Toll-like receptor (TLR) 3, and the adaptor proteins MyD88 and TRIF. We found that pretreatment of BV2 cells with RANKL for 24 h before the LPS or Poly I: C exposure decreases the expression of inflammatory markers such as inducible nitric oxide synthase and cyclooxygenase. This is accompanied by a decreased expression of the TLR adaptor proteins MyD88 and TRIF, which we observed after RANKL treatment. Similar results were obtained in our experiments with primary mouse microglia. Using recently developed CRISPR/Cas9 technology, we generated a BV2 cell line lacking RANK (RANK(-/-) BV2). We showed that most effects of RANKL pretreatment were abolished, thereby proving the specificity of this effect. Taken together, these findings suggest that RANK signalling is important for modulating the inflammatory activation of microglial cells to a moderate level, and that RANK attenuates TLR3/TLR4 signalling. (C) 2017 The Author(s) Published by S. Karger AG, Basel
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22.
  • O'Sullivan, MP, et al. (författare)
  • Validation of Raised Cord Blood Interleukin-16 in Perinatal Asphyxia and Neonatal Hypoxic-Ischaemic Encephalopathy in the BiHiVE2 Cohort
  • 2018
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 40:3, s. 271-277
  • Tidskriftsartikel (refereegranskat)abstract
    • The role of inflammation is an important factor in the progression of hypoxic-ischaemic encephalopathy (HIE). We have previously shown that interleukin-16 (IL-16) is increased in infants with moderate and severe HIE and relates to poor neurodevelopmental outcomes. We aimed to validate IL-16 as a cord blood-based biomarker for HIE and to examine its relationship to long-term outcomes. The study sample consisted of 105 full-term infants who experienced perinatal asphyxia (PA) (with and without an encephalopathy) along with healthy, gestational age-matched newborn controls. Umbilical cord blood serum was processed and biobanked at delivery. Infants were assigned a modified Sarnat score at 24 h. Analysis of IL-16 cytokine cord blood levels was performed using the sandwich-based enzyme-linked immunosorbent assay (ELISA) technique. Cord blood-based IL-16 was increased in infants with PA and HIE relative to controls (<i>p =</i> 0.025). IL-16 was also increased in the HIE group relative to controls (<i>p =</i> 0.042). There was no significant difference in IL-16 across grades of HIE or in those with abnormal outcomes at 2 years of age. This study validates findings that cord blood-based IL-16 levels are increased in infants with PA, including those who go on to develop HIE.
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23.
  • Roughton, Karolina, 1977, et al. (författare)
  • Lipopolysaccharide-Induced Inflammation Aggravates Irradiation-Induced Injury to the Young Mouse Brain.
  • 2013
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 35:5, s. 406-415
  • Tidskriftsartikel (refereegranskat)abstract
    • Radiotherapy is an effective treatment strategy in the treatment of brain tumors, but it is also a major cause of long-term complications, especially in survivors of pediatric brain tumors. Cognitive decline caused by cranial radiotherapy is thought, at least partly, to depend on injury to stem and progenitor cells in the dentate gyrus of the hippocampus. This study investigated the effects of lipopolysaccharide (LPS)-induced inflammation at the time of irradiation (IR) in the growing mouse brain. A single injection of LPS (0.3 mg/kg) was administered 24 h prior to cranial IR of 14-day-old male mice. LPS pretreatment increased the levels of the chemokine CCL2 and the cytokine IL-1β in the brain by 440 and 560%, respectively, compared to IR alone. IR disrupted hippocampal neurogenesis and the growth of the dentate gyrus, and the mice pretreated with LPS displayed an even more pronounced lack of growth than the vehicle-treated group 2 months after IR. The density of microglia was not affected, but LPS-pretreated mice displayed 48% fewer bromodeoxyuridine-positive cells and 43% fewer doublecortin-positive cells in the granule cell layer 2 months after IR compared with the vehicle-treated group. In conclusion, an ongoing inflammation in the brain at the time of IR further enhanced the IR-induced loss of neurogenesis, and may aggravate future cognitive deficits in patients treated with cranial radiotherapy.
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24.
  • Smith, Peter L P, 1982, et al. (författare)
  • Neonatal Peripheral Immune Challenge Activates Microglia and Inhibits Neurogenesis in the Developing Murine Hippocampus.
  • 2014
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 36:2, s. 119-131
  • Tidskriftsartikel (refereegranskat)abstract
    • The early postnatal period represents an important window in rodent hippocampal development with peak hilar neurogenesis and widespread microgliogenesis occurring in the first week of life. Inflammation occurring during this period may negatively influence development, potentially facilitating or increasing susceptibility to later-life pathology. We administered the Gram-negative bacterial coat protein lipopolysaccharide (LPS) systemically at postnatal day 5 (1 mg/kg i.p.) and assessed potential effects on microgliogenesis, inflammation and neurogenesis in the developing hippocampus. LPS administration led to an acute but transient increase in absolute number and density of ionized calcium-binding adaptor molecule 1-immunoreactive microglia, a change attributable to increased proliferation of central nervous system-resident microglia/microglial precursor cells but not infiltration of peripheral monocyte-derived macrophages. qRT-PCR analysis of hippocampal gene expression showed these LPS-mediated changes to be associated with persistent dysregulation of genes associated with both M1 and M2 microglial phenotypes, indicating prolonged alteration in hippocampal inflammatory status. Further, analysis of progenitor cell regulation in the hippocampal subgranular zone revealed a transient inhibition of the neuronal differentiation pathway up to 2 weeks after LPS administration, a change occurring specifically through effects on type 3 neural progenitor cells and independently of altered cell proliferation or survival of newly born cells. Together, our results show that systemic inflammation occurring during the early neonatal period is sufficient to alter inflammatory status and dysregulate the ongoing process of neurogenesis in the developing hippocampal germinal niche. © 2014 S. Karger AG, Basel.
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25.
  • Svedin, Pernilla, 1979, et al. (författare)
  • Delayed peripheral administration of a GPE analogue induces astrogliosis and angiogenesis and reduces inflammation and brain injury following hypoxia-ischemia in the neonatal rat.
  • 2007
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 29:4-5, s. 393-402
  • Tidskriftsartikel (refereegranskat)abstract
    • Glycine 2-methyl proline glutamate (G-2mPE) is a proline-modified analogue to the naturally existing N-terminal tripeptide glycine-proline-glutamate that is a cleaved product from insulin-like growth factor-1. G-2mPE is designed to be more enzymatically resistant than glycine-proline-glutamate and to increase its bioavailability. The current study has investigated the protective effects of G-2mPE following hypoxic-ischemic brain injury in the neonatal brain. On postnatal day 7, Wistar rats were exposed to hypoxia-ischemia (HI). HI was induced by unilateral ligation of the left carotid artery followed by hypoxia (7.7% O2, 36 degrees C) for 60 min. The drug treatment started 2 h after the insult, and the pups were given either 1.2 mg/kg (bolus), 1.2 mg/ml once a day for 7 days, or vehicle. The degree of brain damage was determined histochemically by thionin/acid fuchsin staining. G-2mPE's anti-inflammatory properties were investigated by IL-1beta, IL-6, and IL-18 ELISA, and effects on apoptosis by caspase 3 activity. Vascularization was determined immunohistochemically by the total length of isolectin-positive blood vessels. Effect on astrocytosis was also determined in the hippocampus. Animals treated with multiple doses of G-2mPE demonstrated reduced overall brain injury 7 days after HI, particularly in the hippocampus and thalamus compared to vehicle-treated rats. The expression of IL-6 was decreased in G-2mPE-treated animals compared to vehicle-treated pups, and both the capillary length and astrogliosis were increased in the drug-treated animals. There was no effect on caspase 3 activity. This study indicates that peripheral administration of G-2mPE, starting 2 h after a hypoxic-ischemic insult, reduces the degree of brain injury in the immature rat brain. The normalization of IL-6 levels and the promotion of both neovascularization and reactive astrocytosis may be potential mechanisms that underlie its protective effects.
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26.
  • Svedin, Pernilla, 1979, et al. (författare)
  • Expression of MMP-12 after neonatal hypoxic-ischemic brain injury in mice.
  • 2009
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 31:5, s. 427-36
  • Tidskriftsartikel (refereegranskat)abstract
    • Matrix metalloproteinase-12 (MMP-12) is expressed in the brain and is important for myelin formation in the developing brain, while MMP-12 deficiency protects against spinal cord injury in the adult, suggesting a role for MMP-12 after brain injury. However, the role of MMP-12 in neonatal hypoxic-ischemic brain injury is not known. The purpose of this study was to investigate the expression of MMP-12 in the brain after neonatal hypoxia-ischemia (HI). HI was induced by unilateral ligation of the left carotid artery followed by hypoxia (10% O(2), 36 degrees C) for 50 min in postnatal day 9 C57/Bl6J mice. At 24 and 72 h after HI, the mRNA and protein expression of MMP-12 were measured by real-time PCR and Western blot, respectively. Distribution and cellular expression of MMP-12 were examined by immunohistochemistry. At 72 h after HI, both MMP-12 mRNA and protein expression were significantly increased in the ipsilateral hemisphere compared to the contralateral hemisphere and sham-operated animals (p < 0.05). The extent of tissue loss in the ipsilateral hemisphere at 72 h after HI was positively correlated with the degree of MMP-12 protein expression (r = 0.900, p < 0.05). In nonischemic animals, immunohistochemical analysis demonstrated weak cytoplasmic MMP-12 immunoreactivity throughout the brain in cells which resembled neurons and stronger immunoreactivity was observed in blood vessels. After HI, the MMP-12 staining became more prominent in the ipsilateral hemisphere and immunohistochemical double-labeling experiments identified the MMP-12-positive cells as neurons, isolectin and Olig2-positive cells. This study demonstrates that MMP-12 is upregulated after HI, suggesting that MMP-12 may contribute to injury in the immature brain, similar to that seen in the adult.
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27.
  • Sveinsdóttir, Kristbjörg, et al. (författare)
  • Impaired Cerebellar Maturation, Growth Restriction, and Circulating Insulin-Like Growth Factor 1 in Preterm Rabbit Pups
  • 2017
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 39:6, s. 487-497
  • Tidskriftsartikel (refereegranskat)abstract
    • Cerebellar growth is impeded following very preterm birth in human infants and the observed reduction in cerebellar volume is associated with neurodevelopmental impairment. Decreased levels of circulating insulin-like growth factor 1 (IGF-1) are associated with decreased cerebellar volume. The relationship between preterm birth, circulating IGF-1, and key cell populations supporting cerebellar proliferation is unknown. The aim of this study was to evaluate the effect of preterm birth on postnatal growth, circulating IGF-1, and cerebellar maturation in a preterm rabbit pup model. Preterm rabbit pups (PT) were delivered by cesarean section at day 29 of gestation, cared for in closed incubators with humidified air, and gavage fed with formula. Control term pups (T) delivered by spontaneous vaginal delivery at day 32 of gestation were housed and fed by their lactating doe. In vivo perfusion-fixation for immunohistochemical evaluation of cerebellar prolif-eration, cell maturation, and apoptosis was performed at repeated time points in PT and T pups. Results show that the mean weight of the pups and circulating IGF-1 protein levels were lower in the PT group at all time points (p < 0.05) than in the T group. Postnatal weight development correlated with circulating IGF-1 (r(2) = 0.89) independently of gestational age at birth and postnatal age. The proliferative (Ki-67-positive) portion of the external granular layer (EGL) was decreased in the PT group at postnatal day 2 (P2) compared to in the T group (p = 0.01). Purkinje cells exhibited decreased calbindin staining at P0 (p = 0.003), P2 (p = 0.004), and P5 (p = 0.04) in the PT group compared to in the T group. Staining for sonic hedgehog was positive in neuronal EGL progenitors and Purkinje cells at early time points but was restricted to a welldefined Purkinje cell monolayer at later time points. Preterm birth in rabbit pups is associated with lower circulating levels of IGF-1, decreased postnatal growth, and decreased cerebellar EGL proliferation and Purkinje cell maturation. The preterm rabbit pup model exhibits important characteristics of human preterm birth, and may thus be suitable for the evaluation of interventions aiming to modify growth and cerebellar development in the preterm population. (C) 2017 S. Karger AG, Basel
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28.
  • Sveinsdottir, Snjolaug, et al. (författare)
  • Altered Expression of Aquaporin 1 and 5 in the Choroid Plexus following Preterm Intraventricular Hemorrhage.
  • 2014
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 36:6, s. 542-551
  • Tidskriftsartikel (refereegranskat)abstract
    • Intraventricular hemorrhage (IVH) with posthemorrhagic ventricular dilatation (PHVD) is a common cause of hydrocephalus in infants. Dysregulation of cerebrospinal fluid (CSF) production by the choroid plexus may contribute to the development of PHVD. The aquaporins (AQPs), transmural water transporting proteins, are believed to contribute to CSF production. The aim of the study was to characterize the expression and localization of AQP1, 4 and 5 in the choroid plexus following preterm IVH. Using a preterm rabbit pup model, the mRNA expression, protein level and localization of AQP1, 4 and 5 were investigated in the choroid plexus at 24 and 72 h following IVH with PHVD. Further, AQP1, 4 and 5 expression were characterized in primary human plexus epithelial cells exposed to CSF from preterm human infants with IVH and to hemoglobin metabolites. IVH with PHVD in the immature brain caused a downregulation of AQP1 mRNA, the key AQP in CSF production, but an upregulation of AQP1 protein level with apical epithelial cell localization. Notably, AQP5 was expressed in the choroid plexus with upregulated mRNA expression and protein levels during PHVD with apical epithelial cell localization. Analysis of human choroid plexus epithelial cells in vitro, following exposure to posthemorrhagic CSF and to hemin, displayed results concordant with those observed in vivo, i.e. downregulation of AQP1 mRNA and upregulation of AQP5 mRNA expression. AQP4 was neither detectable in vivo nor in vitro. The changes observed in AQP1 and AQP5 expression in the choroid plexus suggest an adaptive response following IVH with possible functional implications for the development of PHVD. © 2014 S. Karger AG, Basel.
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29.
  • Sävman, Karin, 1960, et al. (författare)
  • Galectin-3 Modulates Microglia Inflammation in vitro but Not Neonatal Brain Injury in vivo under Inflammatory Conditions
  • 2021
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 43:5, s. 296-311
  • Tidskriftsartikel (refereegranskat)abstract
    • Microglia may contribute to injury but may also have neuroprotective properties. Galectin-3 has immunomodulatory properties that may affect the microglia phenotype and subsequent development of injury. Galectin-3 contributes to experimental hypoxic-ischemic (HI) injury in the neonatal brain, but it is unclear if galectin-3 has similar effects on infectious and sterile inflammation. Thus, we investigated the effect of galectin-3 on microglia in vitro under normal as well as infectious and sterile inflammatory conditions, and the effect of galectin-3 on neonatal brain injury following an infectious challenge in vivo. Conditions mimicking infectious or sterile inflammation were evaluated in primary microglia cell cultures from newborn mice, using LPS (10 ng/mL) and TNF-alpha (100 ng/mL). The response to galectin-3 was tested alone or together with LPS or TNF-alpha. Supernatants were collected 24 h after treatment and analyzed for 23 inflammatory mediators including pro- and anti-inflammatory cytokines and chemokines using multiplex protein analysis, as well as ELISA for MCP-1 and insulin-like growth factor (IGF)-1. Phosphorylation of proteins (AKT, ERK1/2, I kappa B-alpha, JNK, and p38) was determined in microglia cells. Neonatal brain injury was induced by a combination of LPS and HI (LPS + HI) in postnatal day 9 transgenic mice lacking functional galectin-3 and wild-type controls. LPS and TNF-alpha induced pro-inflammatory (9/11 vs. 9/10) and anti-inflammatory (6/6 vs. 2/6) cytokines, as well as chemokines (6/6 vs. 4/6) in a similar manner, except generally lower amplitude of the TNF-alpha-induced response. Galectin-3 alone had no effect on any of the proteins analyzed. Galectin-3 reduced the LPS- and TNF-alpha-induced microglia response for cytokines, chemokines, and phosphorylation of I kappa B-alpha. LPS decreased baseline IGF-1 levels, and the levels were restored by galectin-3. Brain injury or microglia response after LPS + HI was not affected by galectin-3 deficiency. Galectin-3 has no independent effect on microglia but modulates inflammatory activation in vitro. The effect was similar under infectious and sterile inflammatory conditions, suggesting that galectin-3 regulates inflammation not just by binding to LPS or toll-like receptor-4. Galectin-3 restores IGF-1 levels reduced by LPS-induced inflammation, suggesting a potential protective effect on infectious injury. However, galectin-3 deficiency did not affect microglia activation and was not beneficial in an injury model encompassing an infectious challenge.
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30.
  • Sävman, Karin, 1960, et al. (författare)
  • Non-protein-bound iron in brain interstitium of newborn pigs after hypoxia
  • 2005
  • Ingår i: Dev Neurosci. - : S. Karger AG. - 0378-5866. ; 27:2-4, s. 176-84
  • Tidskriftsartikel (refereegranskat)abstract
    • Oxidative damage is implied in perinatal hypoxic-ischemic brain injury, most importantly in white matter. Nonprotein-bound iron (NPBI) catalyzes the formation of toxic hydroxyl radicals. We measured the extracellular level of NPBI through microdialysis in the cortex, striatum, and periventricular white matter before, during and after severe hypoxia in newborn pigs. NPBI was analyzed by a new spectrophotometric method in which ferrous iron is chelated by bathophenanthroline. NPBI was present in all brain areas under baseline conditions and increased in white matter from 0.97 (0.69) to 2.75 (1.85) micromol/l (not corrected for recovery rate) during early reoxygenation. NPBI may contribute to oxidative injury after perinatal hypoxic insults.
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31.
  • Tagin, M., et al. (författare)
  • Beneficence and Nonmaleficence in Treating Neonatal Hypoxic-Ischemic Brain Injury
  • 2015
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 37:4-5, s. 305-310
  • Forskningsöversikt (refereegranskat)abstract
    • The successful clinical translation of therapeutic hypothermia offers the tantalizing possibility that further improvements in outcomes may be possible by combining cooling with other neuroprotective drugs. The challenge now is to select from a daunting range of potential treatments. The patient's best interest must be central to ethical decision making at all times. However, the beneficence or nonmaleficence of potential therapies is seldom clear for any individual patient at the time of testing new therapies. Clinical randomized controlled trials are generally acknowledged by the scientific community as the 'gold standard' for evaluating interventions in health care. Therefore, ethical trial design is of the utmost importance. This paper explores contrasting ethical perspectives on how to select new interventions to treat neonatal encephalopathy after perinatal hypoxia-ischemia. (C) 2015 S. Karger AG, Basel
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32.
  • Venero, JL, et al. (författare)
  • Caspases playing in the field of neuroinflammation: old and new players
  • 2013
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 35:2-3, s. 88-101
  • Tidskriftsartikel (refereegranskat)abstract
    • Neuroinflammation is a complex immune response against the harmful effects of diverse stimuli within the central nervous system. Caspases are a family of intracellular cysteine proteases that mediate proteolytic events indispensable for transduction of signaling pathway-controlling biological phenomena such as apoptosis and inflammation. To date, 14 players have been identified in mammals. For many years, caspases were simply divided into ‘apoptotic' and ‘proinflammatory' caspases and this classification remains useful to some extent. However, increasing evidence indicates that many of these so-called apoptotic caspases also exert nonapoptotic functions. In addition, the role of certain members of the supposed inflammatory caspases in the inflammatory process per se has also been discussed. In this review, we highlight the role for ‘apoptotic' and ‘proinflammatory' caspases in the regulation of the inflammation response with a special focus on the central nervous system.
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33.
  • Vontell, R, et al. (författare)
  • Toll-Like Receptor 3 Expression in Glia and Neurons Alters in Response to White Matter Injury in Preterm Infants.
  • 2013
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 35:2-3, s. 130-139
  • Tidskriftsartikel (refereegranskat)abstract
    • Toll-like receptors (TLRs) are members of the pattern recognition receptor family that detect components of foreign pathogens or endogenous molecules released in response to injury. Recent studies demonstrate that TLRs also have a functional role in regulating neuronal proliferation in the developing brain. This study investigated cellular expression of TLR3 using immunohistochemistry on human brain tissue. The tissue sections analysed contained anterior and lateral periventricular white matter from the frontal and parietal lobes in post-mortem neonatal cases with a postmenstrual age range of 23.6-31.4 weeks. In addition to preterm brains without overt pathology (control), preterm pathology cases with evidence of white matter injuries (WMI) were also examined. In order to identify TLR-positive cells, we utilized standard double-labelling immunofluorescence co-labelling techniques and confocal microscopy to compare co-expression of TLR3 with a neuronal marker (NeuN) or with glial markers (GFAP for astrocytes, Iba-1 for microglia and Olig2 for oligodendrocytes). We observed an increase in the neuronal (28 vs. 17%) and astroglial (38 vs. 21%) populations in the WMI group compared to controls in the anterior regions of the periventricular white matter in the frontal lobe. The increase in neurons and astrocytes in the WMI cases was associated with an increase in TLR3 immunoreactivity. This expression was significantly increased in the astroglia. The morphology of the TLR3 signal in the control cases was globular and restricted to the perinuclear region of the neurons and astrocytes, whilst in the cases of WMI, both neuronal, axonal and astroglial TLR3 expression was more diffuse (i.e., a different intracellular distribution) and could be detected along the extensions of the processes. This study demonstrates for the first time that neurons and glial cells in human neonatal periventricular white matter express TLR3 during development. The patterns of TLR3 expression were altered in the presence of WMI, which might influence normal developmental processes within the immature brain. Identifying changes in TLR3 expression during fetal development may be key to understanding the reduced volumes of grey matter and impaired cortical development seen in preterm infants.
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34.
  • Wood, Teresa L, et al. (författare)
  • Delayed IGF-1 administration rescues oligodendrocyte progenitors from glutamate-induced cell death and hypoxic-ischemic brain damage.
  • 2007
  • Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 29:4-5, s. 302-10
  • Tidskriftsartikel (refereegranskat)abstract
    • We previously demonstrated that IGF-1 blocks glutamate-mediated death of late oligodendrocyte progenitors (OPs) by preventing Bax translocation, mitochondrial cytochrome c release and cleavage of caspases 9 and 3. Here, we demonstrate that IGF-1 prevents caspase 3 activation in late OPs when administered up to 16 h following exposure to glutamate. Moreover, late addition of IGF-1 to OPs previously exposed to toxic levels of glutamate promotes oligodendrocyte maturation as measured by myelin basic protein expression. We also demonstrate that intraventricularly administered IGF-1 retains OPs in the perinatal white matter after hypoxia-ischemia when given after insult. These results suggest that delayed administration of IGF-1 will rescue OPs in the immature white matter and promote myelination following hypoxia-ischemia.
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35.
  • Xu, Yiran, 1988, et al. (författare)
  • Cranial Irradiation Induces Hypothalamic Injury and Late-Onset Metabolic Disturbances in Juvenile Female Rats.
  • 2018
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 40:2, s. 120-33
  • Tidskriftsartikel (refereegranskat)abstract
    • Cranial radiotherapy is one of the most effective tools for treating children with brain tumors. However, radiotherapy-induced late-onset side effects have a significant impact on patients' quality of life. The purpose of this study was to investigate the effects of irradiation on metabolism and the possible molecular and cellular mechanisms behind such effects. Female Wistar rats were subjected to a single dose of 6-Gy whole-brain irradiation on postnatal day 11. The animals were sacrificed 6 h or 20 weeks after irradiation. Cell death and proliferation, microglial activation, and inflammation were analyzed and RNA sequencing was performed. We found that irradiation led to a significantly increased body weight from 15 weeks (p < 0.05) along with white adipose tissue accumulation and adipocyte hypertrophy at 20 weeks, and these changes were accompanied by glucose and lipid metabolic disturbances as indicated by reduced glucose tolerance, increased insulin resistance, increased serum triglycerides, and an increased leptin/adiponectin ratio. Furthermore, irradiation induced cell death, microglial activation, inflammation, and persistent astrocyte reactivity in the hypothalamus. Hypothalamic transcriptome analysis showed that 865 genes were downregulated and 290 genes were upregulated in the irradiated group 20 weeks after irradiation, and further pathway analysis showed that the insulin resistance-related PI3K-Akt signaling pathway and the energy expenditure-related adipocytokine signaling pathway were downregulated. Gene Ontology enrichment analysis showed that the expression of fatty acid metabolism-related proteins and effector proteins was significantly different in the irradiation group. This study demonstrates that ionizing radiation to the juvenile female brain induces hypothalamic damage that is likely to be associated with delayed metabolic abnormalities, and this critical vulnerability of the hypothalamus to irradiation should be taken into consideration in the development of future protective strategies for radiotherapy.
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36.
  • Zanni, Giulia, et al. (författare)
  • Irradiation of the Juvenile Brain Provokes a Shift from Long-Term Potentiation to Long-Term Depression
  • 2015
  • Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 37:3, s. 263-272
  • Tidskriftsartikel (refereegranskat)abstract
    • Radiotherapy is common in the treatment of brain tumors in children but often causes deleterious, late-appearing sequelae, including cognitive decline. This is thought to be caused, at least partly, by the suppression of hippocampal neurogenesis. However, the changes in neuronal network properties in the dentate gyrus (DG) following the irradiation of the young, growing brain are still poorly understood. We characterized the long-lasting effects of irradiation on the electrophysiological properties of the DG after a single dose of 6-Gy whole-brain irradiation on postnatal day 11 in male Wistar rats. The assessment of the basal excitatory transmission in the medial perforant pathway (MPP) by an examination of the field excitatory postsynaptic potential/volley ratio showed an increase of the synaptic efficacy per axon in irradiated animals compared to sham controls. The paired-pulse ratio at the MPP granule cell synapses was not affected by irradiation, suggesting that the release probability of neurotransmitters was not altered. Surprisingly, the induction of long-term synaptic plasticity in the DG by applying 4 trains of high-frequency stimulation provoked a shift from long-term potentiation (LTP) to long-term depression (LTD) in irradiated animals compared to sham controls. The morphological changes consisted in a virtually complete ablation of neurogenesis following irradiation, as judged by doublecortin immunostaining, while the inhibitory network of parvalbumin interneurons was intact. These data suggest that the irradiation of the juvenile brain caused permanent changes in synaptic plasticity that would seem consistent with an impairment of declarative learning. Unlike in our previous study in mice, lithium treatment did unfortunately not ameliorate any of the studied parameters. For the first time, we show that the effects of cranial irradiation on long-term synaptic plasticity is different in the juvenile compared with the adult brain, such that while irradiation of the adult brain will only cause a reduction in LTP, irradiation of the juvenile brain goes further and causes LTD. Although the mechanisms underlying the synaptic alterations need to be elucidated, these findings provide a better understanding of the effects of irradiation in the developing brain and the cognitive deficits observed in young patients who have been subjected to cranial radiotherapy. (C) 2015 S. Karger AG, Basel
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37.
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38.
  • Kalinowski, A., et al. (författare)
  • Evaluation of C4 gene copy number in Pediatric Acute Neuropsychiatric Syndrome
  • 2023
  • Ingår i: Developmental Neuroscience. - 0378-5866. ; 45:6, s. 315-324
  • Tidskriftsartikel (refereegranskat)abstract
    • Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) is an abrupt-onset neuropsychiatric disorder. PANS patients have an increased prevalence of co-morbid autoimmune illness, most commonly arthritis. In addition, an estimated one-third of PANS patients present with low serum C4 protein, suggesting decreased production or increased consumption of C4 protein. To test the possibility that copy number (CN) variation contributes to risk of PANS illness, we compared mean total C4A and total C4B CN in ethnically-matched subjects from PANS DNA samples and controls (192 cases and 182 controls). Longitudinal data from the Stanford PANS cohort (n = 121) was used to assess whether the time to Juvenile Idiopathic Arthritis (JIA) or Autoimmune Disease (AI) onset was a function of total C4A or C4B. Lastly, we performed several hypothesis-generating analyses to explore the correlation between individual C4 gene variants, sex, specific genotypes and age of PANS onset. Although the mean total C4A or C4B CN did not differ in PANS compared to controls, PANS patients with low C4B CN were at increased risk for subsequent JIA diagnosis (Hazard Ratio = 2 7, p-value = 0 004). We also observed a possible increase in risk for AI in PANS patients and a possible correlation between lower C4B and PANS age of onset. An association between rheumatoid arthritis and low C4B CN has been reported previously. However, patients with PANS develop different types of JIA: enthesitis-related arthritis, spondyloarthritis and psoriatic arthritis. This suggests that C4B plays a role that spans these arthritis types.
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39.
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40.
  • Payton, K. S., et al. (författare)
  • Antioxidant status alters levels of Fas-associated death domain-like IL-1B-converting enzyme inhibitory protein following neonatal hypoxia-ischemia
  • 2007
  • Ingår i: Dev Neurosci. - 1421-9859. ; 29:4-5, s. 403-11
  • Tidskriftsartikel (refereegranskat)abstract
    • Activation of Fas death receptor (Fas DR) signaling cascade is seen after neonatal hypoxia-ischemia (HI). Cell survival is favored when signaling through the death-inducing signaling complex and cleavage of caspase 8 to its active form is blocked by FLIP, a dominant negative of caspase 8. H2O2 quickly downregulates expression of FLIP. Neonatal mice overexpressing glutathione peroxidase (GPx) have less injury and less H2O2 accumulation compared with neonatal mice overexpressing superoxide dismutase (SOD) or wild-type (WT) littermates. Expression of both FLIP(L) and FLIP(S) is increased in GPx-oxerexpressing mice relative to WT mice at 24 h and relative to SOD-overexpressing mice at 2 and 24 h following neonatal HI (ANOVA, p < 0.05). There is an increase in Fas DR expression at 24 h in both WT and GPx-overexpressing mice and significant differences between WT and SOD-overexpressing mice (ANOVA, p < 0.01). There is no difference in FADD expression among the 3 groups 24 h after HI. At 24 h following HI, the ratio of FLIP to Fas DR expression supports a significant negative correlation with injury score (r2 = 0.99, slope = -4.01), and expression of both the active fragment of caspase 8 and caspase 8 activity is increased in SOD overexpressors compared to GPx overexpressors at 24 h after HI (ANOVA, p < 0.05). The overall degree of injury previously seen in these 3 strains correlates well with changes in expression of Fas DR signaling proteins favoring neuroprotection in the GPx-overexpressing mice, i.e. increased FLIP expression and decreased caspase 8 activity compared to SODtg mice. The mechanism by which antioxidant status alters FLIP levels following neonatal HI may be related to the ability to detoxify H2O2 produced following neonatal HI.
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41.
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42.
  • Svensson-Stadler, Liselott, 1971, et al. (författare)
  • Stenotrophomonas interspecies differentiation and identification by gyrB sequence analysis.
  • 2012
  • Ingår i: FEMS microbiology letters. - : Oxford University Press (OUP). - 1574-6968 .- 0378-1097. ; 327:1, s. 15-24
  • Tidskriftsartikel (refereegranskat)abstract
    • Stenotrophomonas species are found commonly in environmental and clinical samples; Stenotrophomonas maltophilia is an important opportunistic pathogen of humans. Traditional phenotyping protocols, as well as genotyping by 16S rRNA gene sequence analysis, do not reliably distinguish the species of Stenotrophomonas. Sequence analyses of two targeted PCR-amplified regions of the gyrB gene, which encodes the β-subunit of DNA gyrase, enabled resolution and identification of these species. Most type strains of the different species of Stenotrophomonas exhibited more than 7% dissimilarity in the gyrB gene sequences. Among these, strains identified as the same species exhibited sequence dissimilarities up to 4.6% and 5.9% for the two regions, respectively. Strains identified as S. maltophilia, with 16S rRNA gene sequence similarities > 99.0%, were grouped within a 'S. maltophilia complex'; these organisms exhibited gyrB similarities as low as 93%. Many of these strains possessed genomic DNA similarities with the type strain of S. maltophilia CCUG 5866(T) below 70%. These data, including gyrB sequence comparisons, indicate that strains identified as S. maltophilia may comprise distinct, new species.
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