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Sökning: WFRF:(Ek C. Joakim)

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2.
  • Zhou, K., et al. (författare)
  • Radiation induces progenitor cell death, microglia activation, and blood-brain barrier damage in the juvenile rat cerebellum
  • 2017
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Posterior fossa tumors are the most common childhood intracranial tumors, and radiotherapy is one of the most effective treatments. However, irradiation induces long-term adverse effects that can have significant negative impacts on the patient's quality of life. The purpose of this study was to characterize irradiation-induced cellular and molecular changes in the cerebellum. We found that irradiation-induced cell death occurred mainly in the external germinal layer (EGL) of the juvenile rat cerebellum. The number of proliferating cells in the EGL decreased, and 82.9% of them died within 24 h after irradiation. Furthermore, irradiation induced oxidative stress, microglia accumulation, and inflammation in the cerebellum. Interestingly, blood-brain barrier damage and blood flow reduction was considerably more pronounced in the cerebellum compared to other brain regions. The cerebellar volume decreased by 39% and the migration of proliferating cells to the internal granule layer decreased by 87.5% at 16 weeks after irradiation. In the light of recent studies demonstrating that the cerebellum is important not only for motor functions, but also for cognition, and since treatment of posterior fossa tumors in children typically results in debilitating cognitive deficits, this differential susceptibility of the cerebellum to irradiation should be taken into consideration for future protective strategies.
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3.
  • Ek, C. Joakim, et al. (författare)
  • Expression of tight junction proteins and transporters for xenobiotic metabolism at the blood-CSF barrier during development in the nonhuman primate (P. hamadryas)
  • 2015
  • Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238. ; 56, s. 32-44
  • Tidskriftsartikel (refereegranskat)abstract
    • The choroid plexus (CP) is rich in barrier mechanisms including transporters and enzymes which can influence drug disposition between blood and brain. We have limited knowledge of their state in fetus. We have studied barrier mechanisms along with metabolism and transporters influencing xenobiotics, using RNAseq and protein analysis, in the CP during the second-half of gestation in a nonhuman primate (Papio hamadryas). There were no differences in the expression of the tight-junctions at the CP suggesting a well-formed fetal blood-CSF barrier during this period of gestation. Further, the fetal CP express many enzymes for phase I-III metabolisms as well as transporters suggesting that it can greatly influence drug disposition and has a significant machinery to deactivate reactive molecules with only minor gestational changes. In summary, the study suggests that from, at least, midgestation, the CP in the nonhuman primate is restrictive and express most known genes associated with barrier function and transport.
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4.
  • Lehner, C., et al. (författare)
  • The blood-tendon barrier: Identification and characterisation of a novel tissue barrier in tendon blood vessels
  • 2016
  • Ingår i: European Cells and Materials. - 1473-2262. ; 31, s. 296-311
  • Tidskriftsartikel (refereegranskat)abstract
    • Tissue barriers function as “gate keepers” between different compartments (usually blood and tissue) and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF)-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB). By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies. © 2016, AO Research Institute. All rights reserved.
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5.
  • Ek, C. Joakim, et al. (författare)
  • Brain barrier properties and cerebral blood flow in neonatal mice exposed to cerebral hypoxia-ischemia
  • 2015
  • Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 35:5, s. 818-827
  • Tidskriftsartikel (refereegranskat)abstract
    • Insults to the developing brain often result in irreparable damage resulting in long-term deficits in motor and cognitive functions. The only treatment today for hypoxic-ischemic encephalopathy (HIE) in newborns is hypothermia, which has limited clinical benefit. We have studied changes to the blood-brain barriers (BBB) as well as regional cerebral blood flow (rCBF) in a neonatal model of HIE to further understand the underlying pathologic mechanisms. Nine-day old mice pups, brain roughly equivalent to the near-term human fetus, were subjected to hypoxia-ischemia. Hypoxia-ischemia increased BBB permeability to small and large molecules within hours after the insult, which normalized in the following days. The opening of the BBB was associated with changes to BBB protein expression whereas gene transcript levels were increased showing direct molecular damage to the BBB but also suggesting compensatory mechanisms. Brain pathology was closely related to reductions in rCBF during the hypoxia as well as the areas with compromised BBB showing that these are intimately linked. The transient opening of the BBB after the insult is likely to contribute to the pathology but at the same time provides an opportunity for therapeutics to better reach the infarcted areas in the brain.
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6.
  • Ek, C. Joakim, et al. (författare)
  • Transcriptomal changes and functional annotation of the developing non-human primate choroid plexus
  • 2015
  • Ingår i: Frontiers in Neuroscience. - : Frontiers Media SA. - 1662-453X. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • The choroid plexuses are small organs that protrude into each brain ventricle producing cerebrospinal fluid that constantly bathes the brain. These organs differentiate early in development just after neural closure at a stage when the brain is little vascularized. In recent years the plexus has been shown to have a much more active role in brain development than previously appreciated thereby it can influence both neurogenesis and neural migration by secreting factors into the CSF. However, much of choroid plexus developmental function is still unclear. Most previous studies on this organ have been undertaken in rodents but translation into humans is not straightforward since they have a different timing of brain maturation processes. We have collected choroid plexus from three fetal gestational ages of a non-human primate, the baboon, which has much closer brain development to humans. The transcriptome of the plexuses was determined by next generation sequencing and Ingenuity Pathway Analysis software was used to annotate functions and enrichment of pathways of changes in the transcriptome. The number of unique transcripts decreased with development and the majority of differentially expressed transcripts were down-regulated through development suggesting a more complex and active plexus earlier in fetal development. The functional annotation indicated changes across widespread biological functions in plexus development. In particular we find age-dependent regulation of genes associated with annotation categories: Gene Expression, Development of Cardiovascular System, Nervous System Development and Molecular Transport. Our observations support the idea that the choroid plexus has roles in shaping brain development.
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7.
  • Liddelow, S. A., et al. (författare)
  • Mechanisms That Determine the Internal Environment of the Developing Brain: A Transcriptomic, Functional and Ultrastructural Approach
  • 2013
  • Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:7
  • Tidskriftsartikel (refereegranskat)abstract
    • We provide comprehensive identification of embryonic (E15) and adult rat lateral ventricular choroid plexus transcriptome, with focus on junction-associated proteins, ionic influx transporters and channels. Additionally, these data are related to new structural and previously published permeability studies. Results reveal that most genes associated with intercellular junctions are expressed at similar levels at both ages. In total, 32 molecules known to be associated with brain barrier interfaces were identified. Nine claudins showed unaltered expression, while two claudins (6 and 8) were expressed at higher levels in the embryo. Expression levels for most cytoplasmic/regulatory adaptors (10 of 12) were similar at the two ages. A few junctional genes displayed lower expression in embryos, including 5 claudins, occludin and one junctional adhesion molecule. Three gap junction genes were enriched in the embryo. The functional effectiveness of these junctions was assessed using blood-delivered water-soluble tracers at both the light and electron microscopic level: embryo and adult junctions halted movement of both 286Da and 3kDa molecules into the cerebrospinal fluid (CSF). The molecular identities of many ion channel and transporter genes previously reported as important for CSF formation and secretion in the adult were demonstrated in the embryonic choroid plexus (and validated with immunohistochemistry of protein products), but with some major age-related differences in expression. In addition, a large number of previously unidentified ion channel and transporter genes were identified for the first time in plexus epithelium. These results, in addition to data obtained from electron microscopical and physiological permeability experiments in immature brains, indicate that exchange between blood and CSF is mainly transcellular, as well-formed tight junctions restrict movement of small water-soluble molecules from early in development. These data strongly indicate the brain develops within a well-protected internal environment and the exchange between the blood, brain and CSF is transcellular and not through incomplete barriers.
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8.
  • Anderberg, Rozita H, 1976, et al. (författare)
  • Treatment with RNase alleviates brain injury but not neuroinflammation in neonatal hypoxia/ischemia
  • 2024
  • Ingår i: JOURNAL OF NEUROSCIENCE RESEARCH. - 0360-4012 .- 1097-4547. ; 102:4
  • Tidskriftsartikel (refereegranskat)abstract
    • There is a need for new treatments to reduce brain injuries derived from neonatal hypoxia/ischemia. The only viable option used in the clinic today in infants born at term is therapeutic hypothermia, which has a limited efficacy. Treatments with exogenous RNase have shown great promise in a range of different adult animal models including stroke, ischemia/reperfusion injury, or experimental heart transplantation, often by conferring vascular protective and anti-inflammatory effects. However, any neuroprotective function of RNase treatment in the neonate remains unknown. Using a well-established model of neonatal hypoxic/ischemic brain injury, we evaluated the influence of RNase treatment on RNase activity, gray and white matter tissue loss, blood-brain barrier function, as well as levels and expression of inflammatory cytokines in the brain up to 6 h after the injury using multiplex immunoassay and RT-PCR. Intraperitoneal treatment with RNase increased RNase activity in both plasma and cerebropinal fluids. The RNase treatment resulted in a reduction of brain tissue loss but did not affect the blood-brain barrier function and had only a minor modulatory effect on the inflammatory response. It is concluded that RNase treatment may be promising as a neuroprotective regimen, whereas the mechanistic effects of this treatment appear to be different in the neonate compared to the adult and need further investigation.
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9.
  • Andersson, E. Axel, et al. (författare)
  • Circulating tight-junction proteins are potential biomarkers for blood-brain barrier function in a model of neonatal hypoxic/ischemic brain injury
  • 2021
  • Ingår i: Fluids and Barriers of the CNS. - : Springer Science and Business Media LLC. - 2045-8118. ; 18:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Neonatal encephalopathy often leads to lifelong disabilities with limited treatments currently available. The brain vasculature is an important factor in many neonatal neurological disorders but there is a lack of diagnostic tools to evaluate the brain vascular dysfunction of neonates in the clinical setting. Measurement of blood-brain barrier tight-junction (TJ) proteins have shown promise as biomarkers for brain injury in the adult. Here we tested the biomarker potential of tight-junctions in the context of neonatal brain injury. Methods The levels of TJ-proteins (occluding, claudin-5, and zonula occludens protein 1) in both blood plasma and cerebrospinal fluid (CSF) as well as blood-brain barrier function via C-14-sucrose (342 Da) and Evans blue extravasation were measured in a hypoxia/ischemia brain-injury model in neonatal rats. Results Time-dependent changes of occludin and claudin-5 levels could be measured in blood and CSF after hypoxia/ischemia with males generally having higher levels than females. The levels of claudin-5 in CSF correlated with the severity of the brain injury at 24 h post- hypoxia/ischemia. Simultaneously, we detected early increase in blood-brain barrier-permeability at 6 and 24 h after hypoxia/ischemia. Conclusions Levels of circulating claudin-5 and occludin are increased after hypoxic/ischemic brain injuries and blood-brain barrier-impairment and have promise as early biomarkers for cerebral vascular dysfunction and as a tool for risk assessment of neonatal brain injuries.
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10.
  • Andersson, E. Axel, et al. (författare)
  • Function and Biomarkers of the Blood-Brain Barrier in a Neonatal Germinal Matrix Haemorrhage Model
  • 2021
  • Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:7
  • Tidskriftsartikel (refereegranskat)abstract
    • Germinal matrix haemorrhage (GMH), caused by rupturing blood vessels in the germinal matrix, is a prevalent driver of preterm brain injuries and death. Our group recently developed a model simulating GMH using intrastriatal injections of collagenase in 5-day-old rats, which corresponds to the brain development of human preterm infants. This study aimed to define changes to the blood-brain barrier (BBB) and to evaluate BBB proteins as biomarkers in this GMH model. Regional BBB functions were investigated using blood to brain C-14-sucrose uptake as well as using biotinylated BBB tracers. Blood plasma and cerebrospinal fluids were collected at various times after GMH and analysed with ELISA for OCLN and CLDN5. The immunoreactivity of BBB proteins was assessed in brain sections. Tracer experiments showed that GMH produced a defined region surrounding the hematoma where many vessels lost their integrity. This region expanded for at least 6 h following GMH, thereafter resolution of both hematoma and re-establishment of BBB function occurred. The sucrose experiment indicated that regions somewhat more distant to the hematoma also exhibited BBB dysfunction; however, BBB function was normalised within 5 days of GMH. This shows that GMH leads to a temporal dysfunction in the BBB that may be important in pathological processes as well as in connection to therapeutic interventions. We detected an increase of tight-junction proteins in both CSF and plasma after GMH making them potential biomarkers for GMH.
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11.
  • Ardalan, Maryam, 1979, et al. (författare)
  • Dysmaturation of Somatostatin Interneurons Following Umbilical Cord Occlusion in Preterm Fetal Sheep
  • 2019
  • Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 10
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: Cerebral white matter injury is the most common neuropathology observed in preterm infants. However, there is increasing evidence that gray matter development also contributes to neurodevelopmental abnormalities. Fetal cerebral ischemia can lead to both neuronal and non-neuronal structural-functional abnormalities, but less is known about the specific effects on interneurons. Objective: In this study we used a well-established animal model of fetal asphyxia in preterm fetal sheep to study neuropathological outcome. We used comprehensive stereological methods to investigate the total number of oligodendrocytes, neurons and somatostatin (STT) positive interneurons as well as 3D morphological analysis of STT cells 14 days following umbilical cord occlusion (UCO) in fetal sheep. Materials and Methods: Induction of asphyxia was performed by 25 min of complete UCO in five preterm fetal sheep (98-100 days gestational age). Seven, non-occluded twins served as controls. Quantification of the number of neurons (NeuN), STT interneurons and oligodendrocytes (Olig2, CNPase) was performed on fetal brain regions by applying optical fractionator method. A 3D morphological analysis of STT interneurons was performed using IMARIS software. Results: The number of Olig2, NeuN, and STT positive cells were reduced in IGWM, caudate and putamen in UCO animals compared to controls. There were also fewer STT interneurons in the ventral part of the hippocampus, the subiculum and the entorhinal cortex in UCO group, while other parts of cortex were virtually unaffected (p > 0.05). Morphologically, STT positive interneurons showed a markedly immature structure, with shorter dendritic length and fewer dendritic branches in cortex, caudate, putamen, and subiculum in the UCO group compared with control group (p < 0.05). Conclusion: The significant reduction in the total number of neurons and oligodendrocytes in several brain regions confirm previous studies showing susceptibility of both neuronal and non-neuronal cells following fetal asphyxia. However, in the cerebral cortex significant dysmaturation of STT positive neurons occurred in the absence of cell loss. This suggests an abnormal maturation pattern of GABAergic interneurons in the cerebral cortex, which might contribute to neurodevelopmental impairment in preterm infants and could implicate a novel target for neuroprotective therapies.
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12.
  • Baburamani, Ana A, et al. (författare)
  • Vulnerability of the developing brain to hypoxic-ischemic damage: Contribution of the cerebral vasculature to injury and repair?
  • 2012
  • Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 3
  • Tidskriftsartikel (refereegranskat)abstract
    • As clinicians attempt to understand the underlying reasons for the vulnerability of different regions of the developing brain to injury, it is apparent that little is known as to how hypoxia-ischemia may affect the cerebrovasculature in the developing infant. Most of the research investigating the pathogenesis of perinatal brain injury following hypoxia-ischemia has focused on excitotoxicity, oxidative stress and an inflammatory response, with the response of the developing cerebrovasculature receiving less attention. This is surprising as the presentation of devastating and permanent injury such as germinal matrix-intraventricular haemorrhage (GM-IVH) and perinatal stroke are of vascular origin, and the origin of periventricular leukomalacia (PVL) may also arise from poor perfusion of the white matter. This highlights that cerebrovasculature injury following hypoxia could primarily be responsible for the injury seen in the brain of many infants diagnosed with hypoxic-ischemic encephalopathy (HIE). Interestingly the highly dynamic nature of the cerebral blood vessels in the fetus, and the fluctuations of cerebral blood flow and metabolic demand that occur following hypoxia suggest that the response of blood vessels could explain both regional protection and vulnerability in the developing brain. However, research into how blood vessels respond following hypoxia-ischemia have mostly been conducted in adult models of ischemia or stroke, further highlighting the need to investigate how the developing cerebrovasculature responds and the possible contribution to perinatal brain injury following hypoxia. This review discusses the current concepts on the pathogenesis of perinatal brain injury, the development of the fetal cerebrovasculature and the blood brain barrier (BBB), and key mediators involved with the response of cerebral blood vessels to hypoxia. © 2012 Baburamani, Ek, Walker and Castillo-Melendez.
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13.
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14.
  • Bolouri, Hayde, 1957, et al. (författare)
  • Innate defence regulator peptide 1018 protects against perinatal brain injury.
  • 2014
  • Ingår i: Annals of neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 75:3, s. 395-410
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: There is currently no pharmacological treatment that provides protection against brain injury in neonates. It is known that activation of an innate immune response is a key, contributing factor in perinatal brain injury, therefore, the neuroprotective therapeutic potential of innate defence regulator peptides (IDRs) was investigated. Methods: The anti-inflammatory effects of three IDRs was measured in LPS-activated murine microglia. IDRs were then assessed for their ability to confer neuroprotection in vivo when given 3h after neonatal brain injury in a clinically relevant model that combines an inflammatory challenge (LPS) with hypoxia-ischemia (HI). To gain insight into peptide-mediated effects on LPS-induced inflammation and neuroprotective mechanisms, global cerebral gene expression patterns were analyzed in pups that were treated with IDR-1018 either 4 h before LPS or 3h after LPS+HI. Results: IDR-1018 reduced inflammatory mediators produced by LPS-stimulated microglia cells in vitro and modulated LPS-induced neuroinflammation in vivo. When administered 3h after LPS+HI, IDR-1018 exerted effects on regulatory molecules of apoptotic (for e.g. Fadd and Tnfsf9) and inflammatory (for e.g. IL-1, TNF-α, chemokines and cell adhesion molecules) pathways and showed marked protection of both white and grey brain matter. Interpretation: IDR-1018 supresses pro-inflammatory mediators and cell injurious mechanisms in the developing brain, and post-insult treatment is efficacious in reducing LPS-induced hypoxic-ischemic brain damage. IDR-1018 is effective in the brain when given systemically, confers neuroprotection of both grey and white matter, and lacks significant effects on the brain under normal conditions. Thus this peptide provides the features of a promising neuroprotective agent in newborns with brain injury. ANN NEUROL 2013. © 2013 American Neurological Association.
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15.
  • Chumak, Tetyana, 1982, et al. (författare)
  • Maternal n-3 enriched diet reprograms the offspring neurovascular transcriptome and blunts inflammation induced by endotoxin in the neonate
  • 2024
  • Ingår i: JOURNAL OF NEUROINFLAMMATION. - 1742-2094. ; 21:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Infection during the perinatal period can adversely affect brain development, predispose infants to ischemic stroke and have lifelong consequences. We previously demonstrated that diet enriched in n-3 polyunsaturated fatty acids (n-3 PUFA) transforms brain lipid composition in the offspring and protects the neonatal brain from stroke, in part by blunting injurious immune responses. Critical to the interface between the brain and systemic circulation is the vasculature, endothelial cells in particular, that support brain homeostasis and provide a barrier to systemic infection. Here, we examined whether maternal PUFA-enriched diets exert reprograming of endothelial cell signalling in postnatal day 9 mice after modeling aspects of infection using LPS. Transcriptome analysis was performed on microvessels isolated from brains of pups from dams maintained on 3 different maternal diets from gestation day 1: standard, n-3 enriched or n-6 enriched diets. Depending on the diet, in endothelial cells LPS produced distinct regulation of pathways related to immune response, cell cycle, extracellular matrix, and angiogenesis. N-3 PUFA diet enabled higher immune reactivity in brain vasculature, while preventing imbalance of cell cycle regulation and extracellular matrix cascades that accompanied inflammatory response in standard diet. Cytokine analysis revealed a blunted LPS response in blood and brain of offspring from dams on n-3 enriched diet. Analysis of cerebral vasculature in offspring in vivo revealed no differences in vessel density. However, vessel complexity was decreased in response to LPS at 72 h in standard and n-6 diets. Thus, LPS modulates specific transcriptomic changes in brain vessels of offspring rather than major structural vessel characteristics during early life. N-3 PUFA-enriched maternal diet in part prevents an imbalance in homeostatic processes, alters inflammation and ultimately mitigates changes to the complexity of surface vessel networks that result from infection. Importantly, maternal diet may presage offspring neurovascular outcomes later in life.
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16.
  • Chumak, Tetyana, 1982, et al. (författare)
  • Maternal n-3 Polyunsaturated Fatty Acid Enriched Diet Commands Fatty Acid Composition in Postnatal Brain and Protects from Neonatal Arterial Focal Stroke
  • 2022
  • Ingår i: Translational Stroke Research. - : Springer Science and Business Media LLC. - 1868-4483 .- 1868-601X. ; 13:3, s. 449-461
  • Tidskriftsartikel (refereegranskat)abstract
    • The fetus is strongly dependent on nutrients from the mother, including polyunsaturated fatty acids (PUFA). In adult animals, n-3 PUFA ameliorates stroke-mediated brain injury, but the modulatory effects of different PUFA content in maternal diet on focal arterial stroke in neonates are unknown. This study explored effects of maternal n-3 or n-6 enriched PUFA diets on neonatal stroke outcomes. Pregnant mice were assigned three isocaloric diets until offspring reached postnatal day (P) 10-13: standard, long-chain n-3 PUFA (n-3) or n-6 PUFA (n-6) enriched. Fatty acid profiles in plasma and brain of mothers and pups were determined by gas chromatography-mass spectrometry and cytokines/chemokines by multiplex protein analysis. Transient middle cerebral artery occlusion (tMCAO) was induced in P9-10 pups and cytokine and chemokine accumulation, caspase-3 and calpain-dependent spectrin cleavage and brain infarct volume were analyzed. The n-3 diet uniquely altered brain lipid profile in naive pups. In contrast, cytokine and chemokine levels did not differ between n-3 and n-6 diet in naive pups. tMCAO triggered accumulation of inflammatory cytokines and caspase-3-dependent and -independent cell death in ischemic-reperfused regions in pups regardless of diet, but magnitude of neuroinflammation and caspase-3 activation were attenuated in pups on n-3 diet, leading to protection against neonatal stroke. In conclusion, maternal/postnatal n-3 enriched diet markedly rearranges neonatal brain lipid composition and modulates the response to ischemia. While standard diet is sufficient to maintain low levels of inflammatory cytokines and chemokines under physiological conditions, n-3 PUFA enriched diet, but not standard diet, attenuates increases of inflammatory cytokines and chemokines in ischemic-reperfused regions and protects from neonatal stroke.
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17.
  • D'angelo, Barbara, et al. (författare)
  • Expression of the Nrf2-system at the blood-CSF barrier is modulated by neonatal inflammation and hypoxia-ischemia
  • 2013
  • Ingår i: Journal of Inherited Metabolic Disease. - : Wiley. - 0141-8955 .- 1573-2665. ; 36:3, s. 479-490
  • Tidskriftsartikel (refereegranskat)abstract
    • ORIGINAL ARTICLE Expression of the Nrf2-system at the blood-CSF barrier is modulated by neonatal inflammation and hypoxia-ischemia Barbara D ’ Angelo & C. Joakim Ek & Mats Sandberg & Carina Mallard Received: 29 May 2012 /Revised: 14 September 2012 /Accepted: 10 October 2012 /Published online: 30 October 2012 # SSIEM and Springer Science+Business Media Dordrecht 2012 Abstract Transcription factor NF-E2-related factor-2 (Nrf2) is a key regulator of endogenous anti-oxidant sys- tems shown to play a neuroprotective role in the adult by preserving blood – brain barrier function. The choroid plex- us, site for the blood-CSF barrier, has been suggested to be particularly important in maintaining brain barrier function in development. We investigated the expression of Nrf2- and detoxification-system genes in choroid plexus following systemic LPS injections, unilateral cerebral hypoxia- ischemia (HI) as well as the combination of LPS and HI (LPS/HI). Plexuses were collected at different time points after LPS, HI and LPS/HI in 9-day old mice. mRNA levels of Nrf2 and many of its target genes were analyzed by quantitative PCR. Cell death was analyzed by caspase-3 immunostaining and TUNEL. LPS caused down-regulation of the Nrf2-system genes while HI increased expression at earlier time points. LPS exposure prior to HI prevented many of the HI-induced gene increases. None of the insults resulted in any apparent cell death to choroidal epithelium. These data imply that the function of the inducible anti- oxidant system in the choroid plexus is down-regulated by inflammation, even if choroid cells are not structurally damaged. Further, LPS prevented the endogenous antioxi- dant response following HI, suggesting the possibility that the choroid plexus may be at risk if LPS is united with an insult that increases oxidative stress such as hypoxia- ischemia.
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18.
  • D'angelo, Barbara, et al. (författare)
  • GSK3β inhibition protects the immature brain from hypoxic-ischaemic insult via reduced STAT3 signalling
  • 2016
  • Ingår i: Neuropharmacology. - : Elsevier BV. - 0028-3908. ; 101, s. 13-23
  • Tidskriftsartikel (refereegranskat)abstract
    • Hypoxic-ischaemic (HI) injury is an important cause of neurological morbidity in neonates. HI leads to pathophysiological responses, including inflammation and oxidative stress that culminate in cell death. Activation of glycogen synthase kinase 3β (GSK3β) and the signal transducer and activator of transcription (STAT3) promotes brain inflammation. The purpose of this study was to test whether inhibition of GSK3β signalling protects against neonatal HI brain injury. Mice were subjected to HI at postnatal day (PND) 9 and treated with a selective GSK3β inhibitor, SB216763. Brain injury and caspase-3 activation, anti-oxidant and inflammatory mRNA responses and activation of STAT3 were analysed. Our results show that HI reduced phosphorylation of GSK3β, thus promoting its kinase activity. The GSK3β inhibitor reduced caspase-3 activation and neuronal cell death elicited by HI and reverted the effects of HI on gene expression of the anti-oxidant enzyme sod2 and mitochondrial factor pgc1α. The HI insult activated STAT3 in glial cells and GSK3β inhibition attenuated STAT3 phosphorylation and its nuclear translocation following HI. Further, GSK3β inhibition reduced HI-induced gene expression of pro-inflammatory cytokines tnfα and Il-6, while promoted the anti-inflammatory factor Il-10. In summary, data show that GSK3β inhibition is neuroprotective in neonatal HI brain injury likely via reduced pro-inflammatory responses by blocking STAT3 signalling. Our study suggests that pharmacological interventions built upon GSK3β silencing strategies could represent a novel therapy in neonatal brain injury. © 2015 Elsevier Ltd. All rights reserved.
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19.
  • Ek, C. Joakim, et al. (författare)
  • Barriers in the developing brain and Neurotoxicology
  • 2012
  • Ingår i: Neurotoxicology. - : Elsevier BV. - 0161-813X. ; 33:3, s. 586-604
  • Tidskriftsartikel (refereegranskat)abstract
    • The brain develops and grows within a well-controlled internal environment that is provided by cellular exchange mechanisms in the interfaces between blood, cerebrospinal fluid and brain. These are generally referred to by the term "brain barriers": blood-brain barrier across the cerebral endothelial cells and blood-CSF barrier across the choroid plexus epithelial cells. An essential component of barrier mechanisms is the presence of tight junctions between the endothelial and epithelial cells of these interfaces. This review outlines historical evidence for the presence of effective barrier mechanisms in the embryo and newborn and provides an up to date description of recent morphological, biochemical and molecular data for the functional effectiveness of these barriers. Intercellular tight junctions between cerebral endothelial cells and between choroid plexus epithelial cells are functionally effective as soon as they differentiate. Many of the influx and efflux mechanisms are not only present from early in development, but the genes for some are expressed at much higher levels in the embryo than in the adult and there is physiological evidence that these transport systems are functionally more active in the developing brain. This substantial body of evidence supporting the concept of well developed barrier mechanisms in the developing brain is contrasted with the widespread belief amongst neurotoxicologists that "the" blood-brain barrier is immature or even absent in the embryo and newborn. A proper understanding of the functional capacity of the barrier mechanisms to restrict the entry of harmful substances or administered therapeutics into the developing brain is critical. This knowledge would assist the clinical management of pregnant mothers and newborn infants and development of protocols for evaluation of risks of drugs used in pregnancy and the neonatal period prior to their introduction into clinical practice. (c) 2011 Elsevier Inc. All rights reserved.
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20.
  • Ek, C. Joakim, et al. (författare)
  • Novel biomarkers of preterm brain injury from blood transcriptome in sheep model of intrauterine asphyxia
  • 2024
  • Ingår i: PEDIATRIC RESEARCH. - 0031-3998 .- 1530-0447.
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Infants born preterm have a higher incidence of neurological deficits. A key step in finding effective treatments is to identify biomarkers that reliably predict outcome. Methods: Following umbilical cord occlusion (UCO) in pregnant sheep, whole fetal blood RNA was sequenced pre- and post-UCO, brain injury outcome was determined by battery of neuropathology scoring and the transcriptome signature correlated to the degree of brain injury. Additionally, we developed a novel analytical procedure to deduce cell blood composition over time. Results: Sixty-one genes were identified with significant altered expression after UCO. In pre-UCO blood, the level of three mRNAs (Trex2, Znf280b, novel miRNA) and in post-UCO, four mRNAs (Fam184a, Angptl2, novel lincRNA and an unknown protein-coding gene) were associated to brain injury (FDR < 0.01). Several of these mRNAs are related to inflammation and angiogenesis. Pathway analysis highlighted genes playing a role in perinatal death and growth failure. Results also indicate that several leukocyte populations undergo significant changes after UCO. Conclusion: We have used a whole transcriptomic approach to uncover novel biomarkers in fetal blood that correlate to neuropathology in the preterm sheep brain. The current data forms a basis for future studies to investigate mechanisms of these mRNAs in the injury progression.
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21.
  • Ek, C. Joakim, et al. (författare)
  • Pathological Changes in the White Matter after Spinal Contusion Injury in the Rat
  • 2012
  • Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 7:8
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been shown previously that after spinal cord injury, the loss of grey matter is relatively faster than loss of white matter suggesting interventions to save white matter tracts offer better therapeutic possibilities. Loss of white matter in and around the injury site is believed to be the main underlying cause for the subsequent loss of neurological functions. In this study we used a series of techniques, including estimations of the number of axons with pathology, immunohistochemistry and mapping of distribution of pathological axons, to better understand the temporal and spatial pathological events in white matter following contusion injury to the rat spinal cord. There was an initial rapid loss of axons with no detectable further loss beyond 1 week after injury. Immunoreactivity for CNPase indicated that changes to oligodendrocytes are rapid, extending to several millimetres away from injury site and preceding much of the axonal loss, giving early prediction of the final volume of white matter that survived. It seems that in juvenile rats the myelination of axons in white matter tracts continues for some time, which has an important bearing on interpretation of our, and previous, studies. The amount of myelin debris and axon pathology progressively decreased with time but could still be observed at 10 weeks after injury, especially at more distant rostral and caudal levels from the injury site. This study provides new methods to assess injuries to spinal cord and indicates that early interventions are needed for the successful sparing of white matter tracts following injury.
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22.
  • Gravina, Giacomo, et al. (författare)
  • Proteomics identifies lipocalin-2 in neonatal inflammation associated with cerebrovascular alteration in mice and preterm infants
  • 2023
  • Ingår i: iScience. - 2589-0042. ; 26:7
  • Tidskriftsartikel (refereegranskat)abstract
    • Staphylococcus (S.) epidermidis is the most common nosocomial coagulase-negative staphylococci infection in preterm infants. Clinical signs of infection are often unspecific and novel markers to complement diagnosis are needed. We investigated proteomic alterations in mouse brain after S. epidermidis infection and in preterm infant blood. We identified lipocalin-2 (LCN2) as a crucial protein associated with cerebrovascular changes and astrocyte reactivity in mice. We further proved that LCN2 protein expression was associated with endothelial cells but not astrocyte reactivity. By combining network analysis and differential expression approaches, we identified LCN2 linked to blood C-reactive protein levels in pre term infants born <28 weeks of gestation. Blood LCN2 levels were associated with similar alterations of cytokines and chemokines in both infected mice and human preterm infants with increased levels of C-reactive protein. This experimental and clinical study suggests that LCN2 may be a marker of preterm infection/inflammation associated with cerebrovascular changes and neuroinflammation.
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23.
  • Gravina, Giacomo, et al. (författare)
  • Staphylococcus epidermidis Sensitizes Perinatal Hypoxic-Ischemic Brain Injury in Male but Not Female Mice
  • 2020
  • Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Staphylococcus epidermidis is the most common nosocomial infection and the predominant pathogen in late-onset sepsis in preterm infants. Infection and inflammation are linked to neurological and developmental sequelae and bacterial infections increase the vulnerability of the brain to hypoxia-ischemia (HI). We thus tested the hypothesis that S. epidermidis exacerbates HI neuropathology in neonatal mice. Methods: Male and female C57Bl/6 mice were injected intraperitoneally with sterile saline or 3.5 x 10(7) colony-forming units of S. epidermidis on postnatal day (PND) 4 and then subjected to HI on PND5 (24 h after injection) or PND9 (5 d after injection) by left carotid artery ligation and exposure to 10% O-2. White and gray matter injury was assessed on PND14-16. In an additional group of animals, the plasma, brain, and liver were collected on PND5 or PND9 after infection to evaluate cytokine and chemokine profiles, C5a levels and C5 signaling. Results: HI induced 24 h after injection of S. epidermidis resulted in greater gray and white matter injury compared to saline injected controls in males, but not in females. Specifically, males demonstrated increased gray matter injury in the cortex and striatum, and white matter loss in the subcortical region, hippocampal fimbria and striatum. In contrast, there was no potentiation of brain injury when HI occurred 5 d after infection in either sex. In the plasma, S. epidermidis-injected mice demonstrated increased levels of pro- and anti-inflammatory cytokines and chemokines and a reduction of C5a at 24 h, but not 5 d after infection. Brain CCL2 levels were increased in both sexes 24 h after infection, but increased only in males at 5 d post infection. Conclusion: Ongoing S. epidermidis infection combined with neonatal HI increases the vulnerability of the developing brain in male but not in female mice. These sex-dependent effects were to a large extent independent of expression of systemic cytokines or brain CCL2 expression. Overall, we provide new insights into how systemic S. epidermidis infection affects the developing brain and show that the time interval between infection and HI is a critical sensitizing factor in males.
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24.
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25.
  • Hammarlund, Maria, et al. (författare)
  • The Alpha 7 Nicotinic Acetylcholine Receptor Does Not Affect Neonatal Brain Injury
  • 2022
  • Ingår i: Biomedicines. - : MDPI AG. - 2227-9059. ; 10:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Inflammation plays a central role in the development of neonatal brain injury. The alpha 7 nicotinic acetylcholine receptor (alpha 7nAChR) can modulate inflammation and has shown promising results as a treatment target in rodent models of adult brain injury. However, little is known about the role of the alpha 7nAChR in neonatal brain injury. Hypoxic-ischemic (HI) brain injury was induced in male and female C57BL/6 mice, alpha 7nAChR knock-out (KO) mice and their littermate controls on postnatal day (PND) 9-10. C57BL/6 pups received i.p. injections of alpha 7nAChR agonist PHA 568487 (8 mg/kg) or saline once daily, with the first dose given directly after HI. Caspase-3 activity and cytokine mRNA expression in the brain was analyzed 24 h after HI. Motor function was assessed 24 and 48 h after HI, and immunohistochemistry was used to assess tissue loss at 24 h and 7 days after HI and microglial activation 7 days after HI. Activation of alpha 7nAChR with the agonist PHA 568487 significantly decreased CCL2/MCP-1, CCL5/RANTES and IL-6 gene expression in the injured brain hemisphere 24 h after HI compared with saline controls in male, but not female, pups. However, alpha 7nAChR activation did not alter caspase-3 activity and TNF alpha, IL-1 beta and CD68 mRNA expression. Furthermore, agonist treatment did not affect motor function (24 or 48 h), neuronal tissue loss (24 h or 7 days) or microglia activation (7 days) after HI in either sex. Knock-out of alpha 7nAChR did not influence neuronal tissue loss 7 days after HI. In conclusion, targeting the alpha 7nAChR in neonatal brain injury shows some effect on dampening acute inflammatory responses in male pups. However, this does not lead to an effect on overall injury outcome.
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26.
  • Hua, Sansan, et al. (författare)
  • Perinatal Hypoxia-Ischemia Reduces alpha 7 Nicotinic Receptor Expression and Selective alpha 7 Nicotinic Receptor Stimulation Suppresses Inflammation and Promotes Microglial Mox Phenotype
  • 2014
  • Ingår i: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141.
  • Tidskriftsartikel (refereegranskat)abstract
    • Inflammation plays a central role in neonatal brain injury. During brain inflammation the resident macrophages of the brain, the microglia cells, are rapidly activated. In the periphery, alpha 7 nicotinic acetylcholine receptors (alpha 7R) present on macrophages can regulate inflammation by suppressing cytokine release. In the current study we investigated alpha 7R expression in neonatal mice after hypoxia-ischemia (HI). We further examined possible anti-inflammatory role of alpha 7R stimulation in vitro and microglia polarization after alpha 7R agonist treatment. Real-time PCR analysis showed a 33% reduction in alpha 7R expression 72 h after HI. Stimulation of primary microglial cells with LPS in combination with increasing doses of the selective alpha 7R agonist AR-R 17779 significantly attenuated TNF alpha release and increased alpha 7R transcript in microglial cells. Gene expression of M1 markers CD86 and iNOS, as well as M2 marker CD206 was not influenced by LPS and/or alpha 7R agonist treatment. Further, Mox markers heme oxygenase (Hmox1) and sulforedoxin-1 (Srx1) were significantly increased, suggesting a polarization towards the Mox phenotype after alpha 7R stimulation. Thus, our data suggest a role for the alpha 7R also in the neonatal brain and support the anti-inflammatory role of alpha 7R in microglia, suggesting that alpha 7R stimulation could enhance the polarization towards a reparative Mox phenotype.
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27.
  • Jinnai, Masako, et al. (författare)
  • A Model of Germinal Matrix Hemorrhage in Preterm Rat Pups.
  • 2020
  • Ingår i: Frontiers in cellular neuroscience. - : Frontiers Media SA. - 1662-5102. ; 14
  • Tidskriftsartikel (refereegranskat)abstract
    • Germinal matrix hemorrhage (GMH) is a serious complication in extremely preterm infants associated with neurological deficits and mortality. The purpose of the present study was to develop and characterize a grade III and IV GMH model in postnatal day 5 (P5) rats, the equivalent of preterm human brain maturation. P5 Wistar rats were exposed to unilateral GMH through intracranial injection into the striatum close to the germinal matrix with 0.1, 0.2, or 0.3 U of collagenase VII. During 10 days following GMH induction, motor functions and body weight were assessed and brain tissue collected at P16. Animals were tested for anxiety, motor coordination and motor asymmetry on P22-26 and P36-40. Using immunohistochemical staining and neuropathological scoring we found that a collagenase dose of 0.3 U induced GMH. Neuropathological assessment revealed that the brain injury in the collagenase group was characterized by dilation of the ipsilateral ventricle combined with mild to severe cellular necrosis as well as mild to moderate atrophy at the levels of striatum and subcortical white matter, and to a lesser extent, hippocampus and cortex. Within 0.5 h post-collagenase injection there was clear bleeding at the site of injury, with progressive increase in iron and infiltration of neutrophils in the first 24 h, together with focal microglia activation. By P16, blood was no longer observed, although significant gray and white matter brain infarction persisted. Astrogliosis was also detected at this time-point. Animals exposed to GMH performed worse than controls in the negative geotaxis test and also opened their eyes with latency compared to control animals. At P40, GMH rats spent more time in the center of open field box and moved at higher speed compared to the controls, and continued to show ipsilateral injury in striatum and subcortical white matter. We have established a P5 rat model of collagenase-induced GMH for the study of preterm brain injury. Our results show that P5 rat pups exposed to GMH develop moderate brain injury affecting both gray and white matter associated with delayed eye opening and abnormal motor functions. These animals develop hyperactivity and show reduced anxiety in the juvenile stage.
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28.
  • Kalm, Marie, 1981, et al. (författare)
  • Serum concentrations of the axonal injury marker neurofilament light protein are not influenced by blood-brain barrier permeability
  • 2017
  • Ingår i: Brain Research. - : Elsevier BV. - 0006-8993. ; 1668, s. 12-19
  • Tidskriftsartikel (refereegranskat)abstract
    • A blood biomarker to monitor individual susceptibility to neuronal injury from cranial radiotherapy could potentially help to individualize radiation treatment and thereby reduce the incidence and severity of late effects. An important feature of such a blood biomarker is that its concentration is not confounded by varying degrees of release from the brain into the blood across the blood-brain barrier (BBB). In this study, we investigated serum neurofilament light protein (NFL) concentrations in 21-day old mice following a single dose of cranial irradiation (8 Gy). Cranial irradiation resulted in acute cell injury measured as a 12.9-fold increase in caspase activity 6 h after irradiation; activation of inflammation measured by levels of CCL2 and increased BBB permeability measured by C-14-sucrose concentration ratios in brain and cerebrospinal fluid (CSF). Serum levels of NFL peaked at 6 h after both anesthesia and cranial irradiation, but no timely correlation of serum NFL concentration with BBB permeability was found. Further, three groups of patients with different degrees of BBB impairment (measured as the CSF/serum albumin ratio) were investigated. There was no correlation between serum NFL concentration and CSF/serum albumin ratio (r = 0.139, p = 0.3513), however a strong correlation was found for NFL concentration in serum and NFL concentration in CSF (r = 0.6303, p < 0.0001). In conclusion, serum NFL appears to be a reliable blood biomarker for neuronal injury, and its concentration is not confounded by BBB permeability. (C) 2017 Elsevier B.V. All rights reserved.
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29.
  • Koning, Gabriella, et al. (författare)
  • Magnesium induces preconditioning of the neonatal brain via profound mitochondrial protection.
  • 2019
  • Ingår i: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. - 1559-7016. ; 39:6, s. 1038-1055
  • Tidskriftsartikel (refereegranskat)abstract
    • Magnesium sulphate (MgSO4) given to women in preterm labor reduces cerebral palsy in their offspring but the mechanism behind this protection is unclear, limiting its effective, safe clinical implementation. Previous studies suggest that MgSO4 is not neuroprotective if administered during or after the insult, so we hypothesised that MgSO4 induces preconditioning in the immature brain. Therefore, we administered MgSO4 at various time-points before/after unilateral hypoxia-ischemia (HI) in seven-day-old rats. We found that MgSO4 treatment administered as a bolus between 6 days and 12h prior to HI markedly reduced the brain injury, with maximal protection achieved by 1.1mg/g MgSO4 administered 24h before HI. As serum magnesium levels returned to baseline before the induction of HI, we ascribed this reduction in brain injury to preconditioning. Cerebral blood flow was unaffected, but mRNAs/miRNAs involved in mitochondrial function and metabolism were modulated by MgSO4. Metabolomic analysis (H+-NMR) disclosed that MgSO4 attenuated HI-induced increases in succinate and prevented depletion of high-energy phosphates. MgSO4 pretreatment preserved mitochondrial respiration, reducing ROS production and inflammation after HI. Therefore, we propose that MgSO4 evokes preconditioning via induction of mitochondrial resistance and attenuation of inflammation.
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30.
  • Kratzer, I., et al. (författare)
  • The molecular anatomy and functions of the choroid plexus in healthy and diseased brain
  • 2020
  • Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736. ; 1862:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The choroid plexus (CP) is located in the ventricular system of the brain (one in each ventricle), and the CP epithelial cells form an important barrier between the blood and the cerebrospinal fluid (CSF). Their main function comprises CSF secretion, maintenance of brain homeostasis, signalling, and forming a neuroprotective barrier against harmful external and internal compounds. The CPs mature early and demonstrate expressional changes of barrier-specific genes and proteins related to location and developmental stage of the CP. Important proteins for the barrier function include tight junction proteins, numerous transporters and enzymes. Natural senescence leads to structural changes in the CP cells and reduced or loss of function, while further loss of CP function and changes in immune status may be relevant in neurodegenerative diseases such as Alzheimer's disease and Multiple Sclerosis. Neuroprotective genes expressed at CPs may be unexplored targets for new therapies for neurodegenerative diseases. © 2020
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31.
  • Lai, Jacqueline, 1980, et al. (författare)
  • Immune responses in perinatal brain injury.
  • 2017
  • Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 1090-2139 .- 0889-1591. ; 63, s. 210-223
  • Forskningsöversikt (refereegranskat)abstract
    • The perinatal period has often been described as immune deficient. However, it has become clear that immune responses in the neonate following exposure to microbes or as a result of tissue injury may be substantial and play a role in perinatal brain injury. In this article we will review the immune cell composition under normal physiological conditions in the perinatal period, both in the human and rodent. We will summarize evidence of the inflammatory responses to stimuli and discuss how neonatal immune activation, both in the central nervous system and in the periphery, may contribute to perinatal hypoxic-ischemic brain injury.
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32.
  • Lai, Jacqueline, 1980, et al. (författare)
  • Vancomycin Is Protective in a Neonatal Mouse Model of Staphylococcus epidermidis-Potentiated Hypoxic-Ischemic Brain Injury
  • 2020
  • Ingår i: Antimicrobial Agents and Chemotherapy. - : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 64:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Infection is correlated with increased risk of neurodevelopmental sequelae in preterm infants. In modeling neonatal brain injury, Toll-like receptor agonists have often been used to mimic infections and induce inflammation. Using the most common cause of bacteremia in preterm infants, Staphylococcus epidermidis, we present a more clinically relevant neonatal mouse model that addresses the combined effects of bacterial infection together with subsequent hypoxic-ischemic brain insult. Currently, there is no neuroprotective treatment for the preterm population. Hence, we tested the neuroprotective effects of vancomycin with and without adjunct therapy using the anti-inflammatory agent pentoxifylline. We characterized the effects of S. epidermidis infection on the inflammatory response in the periphery and the brain, as well as the physiological changes in the central nervous system that might affect neurodevelopmental outcomes. Intraperitoneal injection of postnatal day 4 mice with a live clinical isolate of S. epidermidis led to bacteremia and induction of proinflammatory cytokines in the blood, as well as transient elevations of neutrophil and monocyte chemotactic cytokines and caspase 3 activity in the brain. When hypoxia-ischemia was induced postinfection, more severe brain damage was observed in infected animals than in saline-injected controls. This infection-induced inflammation and potentiated brain injury was inoculum dose dependent and was alleviated by the antibiotic vancomycin. Pentoxifylline did not provide any additional neuroprotective effect. Thus, we show for the first time that live S. epidermidis potentiates hypoxic-ischemic preterm brain injury and that peripheral inhibition of inflammation with antibiotics, such as vancomycin, reduces the extent of brain injury.
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33.
  • Mallard, Carina, 1963, et al. (författare)
  • The myth of the immature barrier systems in the developing brain: role in perinatal brain injury
  • 2018
  • Ingår i: Journal of Physiology-London. - : Wiley. - 0022-3751. ; 596:23, s. 5655-5664
  • Tidskriftsartikel (refereegranskat)abstract
    • Central nervous system homeostasis is maintained by cellular barriers that protect the brain from external environmental changes and protect the CNS from harmful molecules and pathogens in the blood. Historically, for many years these barriers were thought of as immature, with limited functions, during brain development. In this review, we will present advances in the understanding of the barrier systems during development and evidence to show that in fact the barriers serve many important neurodevelopmental functions and that fetal and newborn brains are well protected. We will also discuss how ischaemic injury or systemic inflammation may breach the integrity of the barriers in the developing brain.
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34.
  • Micallef, Peter, 1988, et al. (författare)
  • Adipose Tissue-Breast Cancer Crosstalk Leads to Increased Tumor Lipogenesis Associated with Enhanced Tumor Growth.
  • 2021
  • Ingår i: International journal of molecular sciences. - 1422-0067. ; 22:21
  • Tidskriftsartikel (refereegranskat)abstract
    • We sought to identify therapeutic targets for breast cancer by investigating the metabolic symbiosis between breast cancer and adipose tissue. To this end, we compared orthotopic E0771 breast cancer tumors that were in direct contact with adipose tissue with ectopic E0771 tumors in mice. Orthotopic tumors grew faster and displayed increased de novo lipogenesis compared to ectopic tumors. Adipocytes release large amounts of lactate, and we found that both lactate pretreatment and adipose tissue co-culture augmented de novo lipogenesis in E0771 cells. Continuous treatment with the selective FASN inhibitor Fasnall dose-dependently decreased the E0771 viability in vitro. However, daily Fasnall injections were effective only in 50% of the tumors, while the other 50% displayed accelerated growth. These opposing effects of Fasnall in vivo was recapitulated in vitro; intermittent Fasnall treatment increased the E0771 viability at lower concentrations and suppressed the viability at higher concentrations. In conclusion, our data suggest that adipose tissue enhances tumor growth by stimulating lipogenesis. However, targeting lipogenesis alone can be deleterious. To circumvent the tumor's ability to adapt to treatment, we therefore believe that it is necessary to apply an aggressive treatment, preferably targeting several metabolic pathways simultaneously, together with conventional therapy.
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35.
  • Moretti, R., et al. (författare)
  • Melatonin reduces excitotoxic blood-brain barrier breakdown in neonatal rats
  • 2015
  • Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522. ; 311, s. 382-397
  • Tidskriftsartikel (refereegranskat)abstract
    • The blood-brain barrier (BBB) is a complex structure that protects the central nervous system from peripheral insults. Understanding the molecular basis of BBB function and dysfunction holds significant potential for future strategies to prevent and treat neurological damage. The aim of our study was (1) to investigate BBB alterations following excitotoxicity and (2) to test the protective properties of melatonin.Ibotenate, a glutamate analog, was injected intracerebrally in postnatal day 5 (P5) rat pups to mimic excitotoxic injury. Animals were than randomly divided into two groups, one receiving intraperitoneal (i.p.) melatonin injections (5. mg/kg), and the other phosphate buffer saline (PBS) injections. Pups were sacrificed 2, 4 and 18. h after ibotenate injection. We determined lesion size at 5. days by histology, the location and organization of tight junction (TJ) proteins by immunohistochemical studies, and BBB leakage by dextran extravasation. Expression levels of BBB genes (TJs, efflux transporters and detoxification enzymes) were determined in the cortex and choroid plexus by quantitative PCR.Dextran extravasation was seen 2. h after the insult, suggesting a rapid BBB breakdown that was resolved by 4. h. Extravasation was significantly reduced in melatonin-treated pups. Gene expression and immunohistochemical assays showed dynamic BBB modifications during the first 4. h, partially prevented by melatonin. Lesion-size measurements confirmed white matter neuroprotection by melatonin.Our study is the first to evaluate BBB structure and function at a very early time point following excitotoxicity in neonates. Melatonin neuroprotects by preventing TJ modifications and BBB disruption at this early phase, before its previously demonstrated anti-inflammatory, antioxidant and axonal regrowth-promoting effects. © 2015 IBRO.
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36.
  • Mottahedin, Amin, et al. (författare)
  • Choroid plexus transcriptome and ultrastructure analysis reveals a TLR2-specific chemotaxis signature and cytoskeleton remodeling in leukocyte trafficking
  • 2019
  • Ingår i: Brain Behavior and Immunity. - : Elsevier BV. - 0889-1591. ; 79, s. 216-227
  • Tidskriftsartikel (refereegranskat)abstract
    • Perinatal infection and inflammation are major risk factors for injury in the developing brain, however, underlying mechanisms are not fully understood. Leukocyte migration to the cerebrospinal fluid (CSF) and brain is a hallmark of many pathologies of the central nervous system including those in neonates. We previously reported that systemic activation of Toll-like receptor (TLR) 2, a major receptor for gram-positive bacteria, by agonist Pam3CSK4 (P3C) resulted in dramatic neutrophil and monocyte infiltration to the CSF and periventricular brain of neonatal mice, an effect that was absent by the TLR4 agonist, LPS. Here we first report that choroid plexus is a route of TLR2-mediated leukocyte infiltration to the CSF by performing flow cytometry and transmission electron microscopy (TEM) of the choroid plexus. Next, we exploited the striking discrepancy between P3C and LPS effects on cell migration to determine the pathways regulating leukocyte trafficking through the choroid plexus. We performed RNA sequencing on the choroid plexus after administration of P3C and LPS to postnatal day 8 mice. A cluster gene analysis revealed a TLR2-specific signature of chemotaxis represented by 80-fold increased expression of the gene Ccl3 and 1000-fold increased expression of the gene Cxcl2. Ingenuity pathway analysis (IPA) revealed TLR2-specific molecular signaling related to cytoskeleton organization (e.g. actin signaling) as well as inositol phospholipids biosynthesis and degradation. This included upregulation of genes such as Rac2 and Micall2. In support of IPA results, ultrastructural analysis by TEM revealed clefting and perforations in the basement membrane of the choroid plexus epithelial cells in P3C-treated mice. In summary, we show that the choroid plexus is a route of TLR2-mediated transmigration of neutrophils and monocytes to the developing brain, and reveal previously unrecognized mechanisms that includes a specific chemotaxis profile as well as pathways regulating cytoskeleton and basement membrane remodeling.
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37.
  • Mottahedin, Amin, et al. (författare)
  • Effect of Neuroinflammation on Synaptic Organization and Function in the Developing Brain: Implications for Neurodevelopmental and Neurodegenerative Disorders
  • 2017
  • Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • The brain is a plastic organ where both the intrinsic CNS milieu and extrinsic cues play important roles in shaping and wiring neural connections. The perinatal period constitutes a critical time in central nervous system development with extensive refinement of neural connections, which are highly sensitive to fetal and neonatal compromise, such as inflammatory challenges. Emerging evidence suggests that inflammatory cells in the brain such as microglia and astrocytes are pivotal in regulating synaptic structure and function. In this article, we will review the role of glia cells in synaptic physiology and pathophysiology, including microglia-mediated elimination of synapses. We propose that activation of the immune system dynamically affects synaptic organization and function in the developing brain. We will discuss the role of neuroinflammation in altered synaptic plasticity following perinatal inflammatory challenges and potential implications for neurodevelopmental and neurodegenerative disorders.
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38.
  • Mottahedin, Amin, et al. (författare)
  • N-acetylcysteine inhibits bacterial lipopeptide-mediated neutrophil transmigration through the choroid plexus in the developing brain
  • 2020
  • Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The etiology of neurological impairments associated with prematurity and other perinatal complications often involves an infectious or pro-inflammatory component. The use of antioxidant molecules have proved useful to protect the neonatal brain from injury. The choroid plexuses-CSF system shapes the central nervous system response to inflammation at the adult stage, but little is known on the neuroimmune interactions that take place at the choroidal blood-CSF barrier during development. We previously described that peripheral administration to neonatal mice of the TLR2 ligand PAM3CSK4 (P3C), a prototypic Gram-positive bacterial lipopeptide, induces the migration of innate immune cells to the CSF. Here we showed in neonatal rats exposed to P3C that the migration of neutrophils into the CSF, which occurred through the choroid plexuses, is abolished following administration of the antioxidant drug N-acetylcysteine. Combining light sheet microscopy imaging of choroid plexus, a differentiated model of the blood-CSF barrier, and multiplex cytokine assays, we showed that the choroidal epithelium responds to the bacterial insult by a specific pattern of cytokine secretion, leading to a selective accumulation of neutrophils in the choroid plexus and to their trafficking into CSF. N-acetylcysteine acted by blocking neutrophil migration across both the endothelium of choroidal stromal vessels and the epithelium forming the blood-CSF barrier, without interfering with neutrophil blood count, neutrophil tropism for choroid plexus, and choroidal chemokine-driven chemotaxis. N-acetylcysteine reduced the injury induced by hypoxia-ischemia in P3C-sensitized neonatal rats. Overall, the data show that a double endothelial and epithelial check point controls the transchoroidal migration of neutrophils into the developing brain. They also point to the efficacy of N-acetylcysteine in reducing the deleterious effects of inflammation-associated perinatal injuries by a previously undescribed mechanism, i.e. the inhibition of innate immune cell migration across the choroid plexuses, without interfering with the systemic inflammatory response to infection.
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39.
  • Mottahedin, Amin, et al. (författare)
  • Systemic activation of Toll-like receptor 2 suppresses mitochondrial respiration and exacerbates hypoxic-ischemic injury in the developing brain
  • 2017
  • Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 37:4, s. 1192-1198
  • Tidskriftsartikel (refereegranskat)abstract
    • Infection and inflammation are known risk factors for neonatal brain injury. Mycoplasma and Gram-positive bacteria, for which Toll-like receptor 2 (TLR2) plays a key role in recognition and inflammatory response, are among the most common pathogens in the perinatal period. Here, we report that systemic activation of TLR2 by Pam3CSK4 (P3C) increases neural tissue loss and demyelination induced by subsequent hypoxia-ischemia (HI) in neonatal mice. High-resolution respirometry of brain isolated mitochondria revealed that P3C suppresses ADP-induced oxidative phosphorylation, the main pathway of cellular energy production. The results suggest that infection and inflammation might contribute to HI-induced energy failure.
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40.
  • Mottahedin, Amin, et al. (författare)
  • TLR2-mediated leukocyte trafficking to the developing brain.
  • 2017
  • Ingår i: Journal of leukocyte biology. - 1938-3673. ; 101:1, s. 297-305
  • Tidskriftsartikel (refereegranskat)abstract
    • Inflammation is a significant risk factor for brain injury in the perinatal period. In this study, we tested the hypothesis that activation of peripheral TLR induces inflammation in the brain, including leukocyte trafficking. Postnatal day 8 mice were injected intraperitoneally with a TLR1/2 (Pam3CSK4, P3C), TLR2/6 (FSL-1) or TLR4 (LPS) agonist, and the peripheral and central cytokine and chemokine response was determined. Infiltration of immune cells to the CSF and brain was examined by flow cytometry, and brain permeability was investigated by radioactively labeled sucrose. We report that peripheral administration of P3C to neonatal mice induces significant influx of leukocytes, mainly neutrophils and monocytes, to the CSF and brain. Infiltration of leukocytes was TLR2 and MyD88 dependent, but largely absent after administration of LPS or FSL-1. PC3-mediated accumulation of immune cells in the brain was observed in classic CNS-leukocyte gateways, the subarachnoid space and choroid plexus, as well as in the median eminence. Although P3C and LPS induced a similar degree of peripheral inflammatory responses, P3C provoked a distinct brain chemokine response and increased permeability, in particular, of the blood-CSF barrier. Collectively, our results do not support the hypothesis that TLR activation, in general, induces immune cell infiltration to the brain. Instead, we have discovered a specific TLR2-mediated mechanism of CNS inflammation and leukocyte invasion into the neonatal brain. This interaction between peripheral and central immune responses is to a large extent via the blood-CSF barrier.
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41.
  • Nilsson, Gisela M A, 1973, et al. (författare)
  • Two different isoforms of osteopontin modulate myelination and axonal integrity
  • 2023
  • Ingår i: Faseb Bioadvances. - 2573-9832. ; 5:8, s. 336-353
  • Tidskriftsartikel (refereegranskat)abstract
    • Abnormal myelination underlies the pathology of white matter diseases such as preterm white matter injury and multiple sclerosis. Osteopontin (OPN) has been suggested to play a role in myelination. Murine OPN mRNA is translated into a secreted isoform (sOPN) or an intracellular isoform (iOPN). Whether there is an isoform-specific involvement of OPN in myelination is unknown. Here we generated mouse models that either lacked both OPN isoforms in all cells (OPN-KO) or lacked sOPN systemically but expressed iOPN specifically in oligodendrocytes (OLs-iOPN-KI). Transcriptome analysis of isolated oligodendrocytes from the neonatal brain showed that genes and pathways related to increase of myelination and altered cell cycle control were enriched in the absence of the two OPN isoforms in OPN-KO mice compared to control mice. Accordingly, adult OPN-KO mice showed an increased axonal myelination, as revealed by transmission electron microscopy imaging, and increased expression of myelin-related proteins. In contrast, neonatal oligodendrocytes from OLs-iOPN-KI mice compared to control mice showed differential regulation of genes and pathways related to the increase of cell adhesion, motility, and vasculature development, and the decrease of axonal/neuronal development. OLs-iOPN-KI mice showed abnormal myelin formation in the early phase of myelination in young mice and signs of axonal degeneration in adulthood. These results suggest an OPN isoform-specific involvement, and a possible interplay between the isoforms, in myelination, and axonal integrity. Thus, the two isoforms of OPN need to be separately considered in therapeutic strategies targeting OPN in white matter injury and diseases.
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42.
  • Rayasam, A., et al. (författare)
  • Viral mimetic triggers cerebral arteriopathy in juvenile brain via neutrophil elastase and NETosis
  • 2021
  • Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016.
  • Tidskriftsartikel (refereegranskat)abstract
    • Stroke is among the top ten causes of death in children but has received disproportionally little attention. Cerebral arteriopathies account for up to 80% of childhood arterial ischemic stroke (CAIS) cases and are strongly predictive of CAIS recurrence and poorer outcomes. The underlying mechanisms of sensitization of neurovasculature by viral infection are undefined. In the first age-appropriate model for childhood arteriopathy-by administration of viral mimetic TLR3-agonist Polyinosinic:polycytidylic acid (Poly-IC) in juvenile mice-we identified a key role of the TLR3-neutrophil axis in disrupting the structural-functional integrity of the blood-brain barrier (BBB) and distorting the developing neurovascular architecture and vascular networks. First, using an array of in-vivo/post-vivo vascular imaging, genetic, enzymatic and pharmacological approaches, we report marked Poly-IC-mediated extravascular leakage of albumin (66kDa) and of a small molecule DiI (similar to 934Da) and disrupted tight junctions. Poly-IC also enhanced the neuroinflammatory milieu, promoted neutrophil recruitment, profoundly upregulated neutrophil elastase (NE), and induced neutrophil extracellular trap formation (NETosis). Finally, we show that functional BBB disturbances, NETosis and neuroinflammation are markedly attenuated by pharmacological inhibition of NE (Sivelestat). Altogether, these data reveal NE/NETosis as a novel therapeutic target for viral-induced cerebral arteriopathies in children.
  •  
43.
  • Samad, Manisha, 1995, et al. (författare)
  • Elevated circulating adiponectin levels do not prevent anxiety-like behavior in a PCOS-like mouse model
  • 2024
  • Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Polycystic ovary syndrome (PCOS) is associated with symptoms of moderate to severe anxiety and depression. Hyperandrogenism is a key feature together with lower levels of the adipocyte hormone adiponectin. Androgen exposure leads to anxiety-like behavior in female offspring while adiponectin is reported to be anxiolytic. Here we test the hypothesis that elevated adiponectin levels protect against the development of androgen-induced anxiety-like behavior. Pregnant mice overexpressing adiponectin (APNtg) and wildtypes were injected with vehicle or dihydrotestosterone to induce prenatal androgenization (PNA) in the offspring. Metabolic profiling and behavioral tests were performed in 4-month-old female offspring. PNA offspring spent more time in the closed arms of the elevated plus maze, indicating anxiety-like behavior. Intriguingly, neither maternal nor offspring adiponectin overexpression prevented an anxiety-like behavior in PNA-exposed offspring. However, adiponectin overexpression in dams had metabolic imprinting effects, shown as lower fat mass and glucose levels in their offspring. While serum adiponectin levels were elevated in APNtg mice, cerebrospinal fluid levels were similar between genotypes. Adiponectin overexpression improved metabolic functions but did not elicit anxiolytic effects in PNA-exposed offspring. These observations might be attributed to increased circulating but unchanged cerebrospinal fluid adiponectin levels in APNtg mice. Thus, increased adiponectin levels in the brain are likely needed to stimulate anxiolytic effects. 
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44.
  • Saunders, N. R., et al. (författare)
  • Age-Dependent Transcriptome and Proteome Following Transection of Neonatal Spinal Cord of Monodelphis domestica (South American Grey Short-Tailed Opossum)
  • 2014
  • Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 9:6
  • Tidskriftsartikel (refereegranskat)abstract
    • This study describes a combined transcriptome and proteome analysis of Monodelphis domestica response to spinal cord injury at two different postnatal ages. Previously we showed that complete transection at postnatal day 7 (P7) is followed by profuse axon growth across the lesion with near-normal locomotion and swimming when adult. In contrast, at P28 there is no axon growth across the lesion, the animals exhibit weight-bearing locomotion, but cannot use hind limbs when swimming. Here we examined changes in gene and protein expression in the segment of spinal cord rostral to the lesion at 24 h after transection at P7 and at P28. Following injury at P7 only forty genes changed (all increased expression); most were immune/inflammatory genes. Following injury at P28 many more genes changed their expression and the magnitude of change for some genes was strikingly greater. Again many were associated with the immune/inflammation response. In functional groups known to be inhibitory to regeneration in adult cords the expression changes were generally muted, in some cases opposite to that required to account for neurite inhibition. For example myelin basic protein expression was reduced following injury at P28 both at the gene and protein levels. Only four genes from families with extracellular matrix functions thought to influence neurite outgrowth in adult injured cords showed substantial changes in expression following injury at P28: Olfactomedin 4 (Olfm4, 480 fold compared to controls), matrix metallopeptidase (Mmp1, 104 fold), papilin (Papln, 152 fold) and integrin alpha 4 (Itga4, 57 fold). These data provide a resource for investigation of a priori hypotheses in future studies of mechanisms of spinal cord regeneration in immature animals compared to lack of regeneration at more mature stages.
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45.
  • Saunders, N. R., et al. (författare)
  • Delayed astrocytic contact with cerebral blood vessels in FGF-2 deficient mice does not compromise permeability properties at the developing blood-brain barrier
  • 2016
  • Ingår i: Developmental Neurobiology. - : Wiley. - 1932-8451. ; 76:11, s. 1201-1212
  • Tidskriftsartikel (refereegranskat)abstract
    • The brain functions within a specialized environment tightly controlled by brain barrier mechanisms. Understanding the regulation of barrier formation is important for understanding brain development and may also lead to finding new ways to deliver pharmacotherapies to the brain; access of many potentially promising drugs is severely hindered by these barrier mechanisms. The cellular composition of the neurovascular unit of the blood-brain barrier proper and their effects on regulation of its function are beginning to be understood. One hallmark of the neurovascular unit in the adult is the astroglial foot processes that tightly surround cerebral blood vessels. However their role in barrier formation is still unclear. In this study we examined barrier function in newborn, juvenile and adult mice lacking fibroblast growth factor-2 (FGF-2), which has been shown to result in altered astroglial differentiation during development. We show that during development of FGF-2 deficient mice the astroglial contacts with cerebral blood vessels are delayed compared with wild-type animals. However, this delay did not result in changes to the permeability properties of the blood brain barrier as assessed by exclusion of either small or larger sized molecules at this interface. In addition cerebral vessels were positive for tight-junction proteins and we observed no difference in the ultrastructure of the tight-junctions. The results indicate that the direct contact of astroglia processes to cerebral blood vessels is not necessary for either the formation of the tight-junctions or for basic permeability properties and function of the blood-brain barrier.
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46.
  • Smith, Peter L P, 1982, et al. (författare)
  • Peripheral myeloid cells contribute to brain injury in male neonatal mice
  • 2018
  • Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 15:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundNeonatal brain injury is increasingly understood to be linked to inflammatory processes that involve specialised CNS and peripheral immune interactions. However, the role of peripheral myeloid cells in neonatal hypoxic-ischemic (HI) brain injury remains to be fully investigated.MethodsWe employed the Lys-EGFP-ki mouse that allows enhanced green fluorescent protein (EGFP)-positive mature myeloid cells of peripheral origin to be easily identified in the CNS. Using both flow cytometry and confocal microscopy, we investigated the accumulation of total EGFP(+) myeloid cells and myeloid cell subtypes: inflammatory monocytes, resident monocytes and granulocytes, in the CNS for several weeks following induction of cerebral HI in postnatal day 9 mice. We used antibody treatment to curb brain infiltration of myeloid cells and subsequently evaluated HI-induced brain injury.ResultsWe demonstrate a temporally biphasic pattern of inflammatory monocyte and granulocyte infiltration, characterised by peak infiltration at 1day and 7days after hypoxia-ischemia. This occurs against a backdrop of continuous low-level resident monocyte infiltration. Antibody-mediated depletion of circulating myeloid cells reduced immune cell accumulation in the brain and reduced neuronal loss in male but not female mice.ConclusionThis study offers new insight into sex-dependent central-peripheral immune communication following neonatal brain injury and merits renewed interest in the roles of granulocytes and monocytes in lesion development.
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47.
  • Song, Juan, et al. (författare)
  • Temporal brain transcriptome analysis reveals key pathological events after germinal matrix hemorrhage in neonatal rats
  • 2022
  • Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 42:9, s. 1632-1649
  • Tidskriftsartikel (refereegranskat)abstract
    • Germinal matrix hemorrhage (GMH) is a common complication in preterm infants and is associated with high risk of adverse neurodevelopmental outcomes. We used a rat GMH model and performed RNA sequencing to investigate the signaling pathways and biological processes following hemorrhage. GMH induced brain injury characterized by early hematoma and subsequent tissue loss. At 6 hours after GMH, gene expression indicated an increase in mitochondrial activity such as ATP metabolism and oxidative phosphorylation along with upregulation of cytoprotective pathways and heme metabolism. At 24 hours after GMH, the expression pattern suggested an increase in cell cycle progression and downregulation of neurodevelopmental-related pathways. At 72 hours after GMH, there was an increase in genes related to inflammation and an upregulation of ferroptosis. Hemoglobin components and genes related to heme metabolism and ferroptosis such as Hmox1, Alox15, and Alas2 were among the most upregulated genes. We observed dysregulation of processes involved in development, mitochondrial function, cholesterol biosynthesis, and inflammation, all of which contribute to neurodevelopmental deterioration following GMH. This study is the first temporal transcriptome profile providing a comprehensive overview of the molecular mechanisms underlying brain injury following GMH, and it provides useful guidance in the search for therapeutic interventions.
  •  
48.
  • Stridh, Linnea, 1983, et al. (författare)
  • Regulation of Toll-Like Receptors in the Choroid Plexus in the Immature Brain After Systemic Inflammatory Stimuli
  • 2013
  • Ingår i: Translational Stroke Research. - : Springer Science and Business Media LLC. - 1868-4483 .- 1868-601X. ; 4:2, s. 220-227
  • Tidskriftsartikel (refereegranskat)abstract
    • The choroid plexus is the site of the blood–cerebrospinal fluid (CSF) barrier (BCSFB) and has also been considered as a possible route for peripheral immune signals and cells to transfer to the central nervous system. Infection/inflammation stimulates innate and subsequent adaptive immune responses via Toll-like receptors (TLRs). In this study, we have investigated the mRNA expression of TLRs, cytokines, and tight junction proteins in the choroid plexus in the immature brain after systemic inflammation, as well as accumulation of immune cells into the CSF. Specific ligands for TLR-1/2, TLR-3, and TLR-4 were administered to postnatal day 8 mice and mRNA expression for the targeted genes was examined in the choroid plexus. We found that mRNA for all four TLRs was detected in the choroid plexus under control conditions. Following immune stimulation, expression of all the TLRs was upregulated by their respective ligands, except for TLR-4 mRNA, which was downregulated by Pam3CSK4 (PAM; a TLR-1/2 ligand). In addition, we investigated BCSFB regulation after TLR stimulation and found that TLR-1/2 and TLR-4 activation was associated with changes in mRNA expression of the tight junction protein occludin in the choroid plexus. PAM induced choroid plexus transcription of TNF-α and resulted in the most dramatic increase in numbers of white blood cells in the CSF. The data suggest a possible mechanism whereby systemic inflammation stimulates TLRs in the choroid plexus, which may lead to disturbances in choroid plexus barrier function, as well as infiltration of immune cells through the plexus.
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49.
  • Wikström, Tove, et al. (författare)
  • Microbial and human transcriptome in vaginal fluid at midgestation: Association with spontaneous preterm delivery.
  • 2022
  • Ingår i: Clinical and translational medicine. - : Wiley. - 2001-1326. ; 12:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Intrauterine infection and inflammation caused by microbial transfer from the vagina are believed to be important factors causing spontaneous preterm delivery (PTD). Multiple studies have examined the relationship between the cervicovaginal microbiome and spontaneous PTD with divergent results. Most studies have applied a DNA-based assessment, providing information on the microbial composition but not transcriptional activity. A transcriptomic approach was applied to investigate differences in the active vaginal microbiome and human transcriptome at midgestation between women delivering spontaneously preterm versus those delivering at term.Vaginal swabs were collected in women with a singleton pregnancy at 18 + 0 to 20 + 6 gestational weeks. For each case of spontaneous PTD (delivery<37 + 0weeks) two term controls were randomized (39 + 0 to 40 + 6weeks). Vaginal specimens were subject to sequencing of both human and microbial RNA. Microbial reads were taxonomically classified using Kraken2 and RefSeq as a reference. Statistical analyses were performed using DESeq2. GSEA and HUMAnN3 were used for pathway analyses.We found 17 human genes to be differentially expressed (false discovery rate, FDR<0.05) in the preterm group (n =48) compared to the term group (n =96). Gene expression of kallikrein-2 (KLK2), KLK3 and four isoforms of metallothioneins 1 (MT1s) was higher in the preterm group (FDR<0.05). We found 11 individual bacterial species to be differentially expressed (FDR<0.05), most with a low occurrence. No statistically significant differences in bacterial load, diversity or microbial community state types were found between the groups.In our mainly white population, primarily bacterial species of low occurrence were differentially expressed at midgestation in women who delivered preterm versus at term. However, the expression of specific human transcripts including KLK2, KLK3 and several isoforms of MT1s was higher in preterm cases. This is of interest, because these genes may be involved in critical inflammatory pathways associated with spontaneous PTD.
  •  
50.
  • Zhang, Shan, et al. (författare)
  • Alpha1-antitrypsin protects the immature mouse brain following hypoxic-ischemic injury
  • 2023
  • Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 17
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: Preterm brain injury often leads to lifelong disabilities affecting both cognitive and motor functions, and effective therapies are limited. Alpha1-antitrypsin (AAT), an endogenous inhibitor of serine proteinases with anti-inflammatory, anti-apoptotic, and cytoprotective properties, might be beneficial in treating preterm brain injury. The aim of this study was to investigate whether AAT has neuroprotective effects in a mouse preterm brain injury model.Methods: Preterm brain injury was induced on postnatal day 5, and mouse pups' right common carotid arteries were cut between two ligations followed by hypoxia induction. Brain injury was evaluated through immunohistochemistry staining and magnetic resonance imaging. Fluoro-Jade B and immunohistochemistry staining were performed to investigate the neuronal cell death and blood-brain barrier (BBB) permeability. The motor function and anxiety-like behaviors were revealed by CatWalk gait analysis and the open field test.Results: After hypoxia-ischemia (HI) insult, brain injury was alleviated by AAT treatment, and this was accompanied by reduced BBB permeability, reduced neuronal cell death and caspase-3 activation, and inhibition of microglia activation. In addition, AAT administration significantly improved HI-induced motor function deficiencies in mice. The neuroprotective effect of AAT was more pronounced in male mice.Conclusion: AAT treatment is neuroprotective against preterm brain injury in neonatal mice, and the effect is more pronounced in males.
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