| 1. |
- Israelsson, Charlotte, et al.
(författare)
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Appearance of Cxcl10-expressing cell clusters is common for traumatic brain injury and neurodegenerative disorders
- 2010
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Ingår i: European Journal of Neuroscience. - : Wiley. - 0953-816X .- 1460-9568. ; 31:5, s. 852-863
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) in the mouse results in the rapid appearance of scattered clusters of cells expressing the chemokine Cxcl10 in cortical and subcortical areas. To extend the observation of this unique pattern, we used neuropathological mouse models using quantitative reverse transcriptase-polymerase chain reaction, gene array analysis, in-situ hybridization and flow cytometry. As for TBI, cell clusters of 150–200 μm expressing Cxcl10 characterize the cerebral cortex of mice carrying a transgene encoding the Swedish mutation of amyloid precursor protein, a model of amyloid Alzheimer pathology. The same pattern was found in experimental autoimmune encephalomyelitis in mice modelling multiple sclerosis. In contrast, mice carrying a SOD1G93A mutant mimicking amyotrophic lateral sclerosis pathology lacked such cell clusters in the cerebral cortex, whereas clusters appeared in the brainstem and spinal cord. Mice homozygous for a null mutation of the Cxcl10 gene did not show detectable levels of Cxcl10 transcript after TBI, confirming the quantitative reverse transcriptase-polymerase chain reaction and in-situ hybridization signals. Moreover, unbiased microarray expression analysis showed that Cxcl10 was among 112 transcripts in the neocortex upregulated at least threefold in both TBI and ageing TgSwe mice, many of them involved in inflammation. The identity of the Cxcl10+ cells remains unclear but flow cytometry showed increased numbers of activated microglia/macrophages as well as myeloid dendritic cells in the TBI and experimental autoimmune encephalomyelitis models. It is concluded that the Cxcl10+ cells appear in the inflamed central nervous system and may represent a novel population of cells that it may be possible to target pharmacologically in a broad range of neurodegenerative conditions.
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| 2. |
- Lord, Anna, 1979-, et al.
(författare)
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Amyloid-β protofibril levels correlate with spatial learning in Arctic Alzheimer’s disease transgenic mice
- 2009
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 276:4, s. 995-1006
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Tidskriftsartikel (refereegranskat)abstract
- Oligomeric assemblies of amyloid-β (Aβ) are suggested to be central in the pathogenesis of Alzheimer's disease because levels of soluble Aβ correlate much better with the extent of cognitive dysfunctions than do senile plaque counts. Moreover, such Aβ species have been shown to be neurotoxic, to interfere with learned behavior and to inhibit the maintenance of hippocampal long-term potentiation. The tg-ArcSwe model (i.e. transgenic mice with the Arctic and Swedish Alzheimer mutations) expresses elevated levels of Aβ protofibrils in the brain, making tg-ArcSwe a highly suitable model for investigating the pathogenic role of these Aβ assemblies. In the present study, we estimated Aβ protofibril levels in the brain and cerebrospinal fluid of tg-ArcSwe mice, and also assessed their role with respect to cognitive functions. Protofibril levels, specifically measured with a sandwich ELISA, were found to be elevated in young tg-ArcSwe mice compared to several transgenic models lacking the Arctic mutation. In aged tg-ArcSwe mice with considerable plaque deposition, Aβ protofibrils were approximately 50% higher than in younger mice, whereas levels of total Aβ were exponentially increased. Young tg-ArcSwe mice showed deficits in spatial learning, and individual performances in the Morris water maze were correlated inversely with levels of Aβ protofibrils, but not with total Aβ levels. We conclude that Aβ protofibrils accumulate in an age-dependent manner in tg-ArcSwe mice, although to a far lesser extent than total Aβ. Our findings suggest that increased levels of Aβ protofibrils could result in spatial learning impairment.
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| 3. |
- Abu Hamdeh, Sami, et al.
(författare)
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Rapid amyloid-β oligomer and protofibril accumulation in traumatic brain injury
- 2018
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Ingår i: Brain Pathology. - : Wiley. - 1015-6305 .- 1750-3639. ; 28:4, s. 451-462
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Tidskriftsartikel (refereegranskat)abstract
- Deposition of amyloid-β (Aβ) is central to Alzheimer's disease (AD) pathogenesis and associated with progressive neurodegeneration in traumatic brain injury (TBI). We analyzed predisposing factors for Aβ deposition including monomeric Aβ40, Aβ42 and Aβ oligomers/protofibrils, Aβ species with pronounced neurotoxic properties, following human TBI. Highly selective ELISAs were used to analyze N-terminally intact and truncated Aβ40 and Aβ42, as well as Aβ oligomers/protofibrils, in human brain tissue, surgically resected from severe TBI patients (n = 12; mean age 49.5 ± 19 years) due to life-threatening brain swelling/hemorrhage within one week post-injury. The TBI tissues were compared to post-mortem AD brains (n = 5), to post-mortem tissue of neurologically intact (NI) subjects (n = 4) and to cortical biopsies obtained at surgery for idiopathic normal pressure hydrocephalus patients (iNPH; n = 4). The levels of Aβ40 and Aβ42 were not elevated by TBI. The levels of Aβ oligomers/protofibrils in TBI were similar to those in the significantly older AD patients and increased compared to NI and iNPH controls (P < 0.05). Moreover, TBI patients carrying the AD risk genotype Apolipoprotein E epsilon3/4 (APOE ε3/4; n = 4) had increased levels of Aβ oligomers/protofibrils (P < 0.05) and of both N-terminally intact and truncated Aβ42 (P < 0.05) compared to APOE ε3/4-negative TBI patients (n = 8). Neuropathological analysis showed insoluble Aβ aggregates (commonly referred to as Aβ plaques) in three TBI patients, all of whom were APOE ε3/4 carriers. We conclude that soluble intermediary Aβ aggregates form rapidly after TBI, especially among APOE ε3/4 carriers. Further research is needed to determine whether these aggregates aggravate the clinical short- and long-term outcome in TBI.
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| 4. |
- Hånell, Anders, et al.
(författare)
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Genetic Deletion and Pharmacological Inhibition of Nogo-66 Receptor Impairs Cognitive Outcome after Traumatic Brain Injury in Mice
- 2010
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 27:7, s. 1297-1309
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Tidskriftsartikel (refereegranskat)abstract
- Functional recovery is markedly restricted following traumatic brain injury (TBI), partly due to myelin-associated inhibitors including Nogo-A, myelin-associated glycoprotein (MAG) and oligodendrocyte myelin glycoprotein (OMgp), that all bind to the Nogo-66 receptor-1 (NgR1). In previous studies, pharmacological neutralization of both Nogo-A and MAG improved outcome following TBI in the rat, and neutralization of NgR1 improved outcome following spinal cord injury and stroke in rodent models. However, the behavioral and histological effects of NgR1 inhibition have not previously been evaluated in TBI. We hypothesized that NgR1 negatively influences behavioral recovery following TBI, and evaluated NgR1(-/-) mice (NgR1(-/-) study) and, in a separate study, soluble NgR1 infused intracerebroventricularly immediately post-injury to neutralize NgR1 (sNgR1 study) following TBI in mice using a controlled cortical impact (CCI) injury model. In both studies, motor function, TBI-induced loss of tissue, and hippocampal beta-amyloid immunohistochemistry were not altered up to 5 weeks post-injury. Surprisingly, cognitive function (as evaluated with the Morris water maze at 4 weeks post-injury) was significantly impaired both in NgR1(-/-) mice and in mice treated with soluble NgR1. In the sNgR1 study, we evaluated hippocampal mossy fiber sprouting using the Timm stain and found it to be increased at 5 weeks following TBI. Neutralization of NgR1 significantly increased mossy fiber sprouting in sham-injured animals, but not in brain-injured animals. Our data suggest a complex role for myelin-associated inhibitors in the behavioral recovery process following TBI, and urge caution when inhibiting NgR1 in the early post-injury period.
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| 5. |
- Marklund, Niklas, et al.
(författare)
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Functional outcome is impaired following traumatic brain injury in aging Nogo-A/B-deficient mice
- 2009
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 163:2, s. 540-551
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Tidskriftsartikel (refereegranskat)abstract
- Increasing age is associated with a poor prognosis following traumatic brain injury (TBI). CNS axons may recover poorly following TBI due to expression of myelin-derived inhibitors to axonal outgrowth such as Nogo-A. To study the role of Nogo-A/B in the pathophysiological response of the elderly to TBI, 1-year-old mice deficient in Nogo-A/B (Nogo-A/B homozygous(-/-) mice), Nogo-A/B heterozygous(-/+) mice, and age-matched wild-type (WT) littermate controls were subjected to a controlled cortical impact (CCI) TBI. Sham-injured WT mice (7 months old) and 12 month old naïve Nogo-A/B(-/-) and Nogo-A/B(-/+) served as controls. Neurological motor function was evaluated up to 3 weeks, and cognitive function, hemispheric tissue loss, myelin staining and hippocampal beta-amyloid (A beta) immunohistochemistry were evaluated at 4 weeks post-injury. In WT littermates, TBI significantly impaired learning ability at 4 weeks and neurological motor function up to 2 weeks post-injury and caused a significant loss of hemispheric tissue. Following TBI, Nogo-A/B(-/-) mice showed significantly less recovery from neurological motor and cognitive deficits compared to brain-injured WT mice. Naïve Nogo-A/B(-/-) and Nogo-A/B(-/+) mice quickly learned the MWM task in contrast to brain-injured Nogo-A/B(-/-) mice who failed to learn the MWM task at 4 weeks post-injury. Hemispheric tissue loss and cortical lesion volume were similar among the brain-injured genotypes. Neither TBI nor the absence of NogoA/B caused an increased A beta expression. Myelin staining showed a reduced area and density in the corpus callosum in brain-injured Nogo-A/B(-/-) animals compared to their littermate controls. These novel and unexpected behavioral results demonstrate that the absence of Nogo-A/B may negatively influence outcome, possibly related to hypomyelination, following TBI in mice and suggest a complex role for this myelin-associated axonal growth inhibitor following TBI.
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| 6. |
- Abu Hamdeh, Sami, 1982-
(författare)
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Clinical Consequences of Axonal Injury in Traumatic Brain Injury
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI), mainly caused by road-traffic accidents and falls, is a leading cause of mortality. Survivors often display debilitating motor, sensory and cognitive symptoms, leading to reduced quality of life and a profound economic burden to society. Additionally, TBI is a risk factor for future neurodegenerative disorders including Alzheimer’s disease (AD). Commonly, TBI is categorized into focal and diffuse injuries, and based on symptom severity into mild, moderate and severe TBI. Diffuse axonal injury (DAI), biomechanically caused by rotational acceleration-deceleration forces at impact, is characterized by widespread axonal injury in superficial and deep white substance. DAI comprises a clinical challenge due to its variable course and unreliable prognostic methods. Furthermore, axonal injury may convey the link to neurodegeneration since molecules associated with neurodegenerative events aggregate in injured axons.The aim of this thesis was to study clinical consequences of axonal injury, its detection and pathological features, and potential link to neurodegeneration in severe TBI patients treated at the neurointensive care unit at Uppsala University Hospital. In paper I and IV DAI patients were studied for the relation of elevated intracranial pressure (ICP) and poor outcome to axonal injury on magnetic resonance imaging. In paper II, soluble amyloid-beta aggregates (oligomers and protofibrils), characteristic of AD pathology, were investigated in surgically resected brain tissue from severe TBI patients, using highly-selective Enzyme-Linked ImmunoSorbent Assays. In paper III, brain tissue biopsy samples from TBI patients with either focal injury or DAI were examined for differential proteome profiles using mass spectrometry-based proteomics.The results provide evidence that axonal injury, located in the central brain stem, in substantia nigra and the mesencephalic tegmentum, is particularly related to poor outcome and increased ICP during neurointensive care of DAI patients. A novel classification system for prognostication after DAI is proposed. Furthermore, the thesis shows that severe TBI induces rapid accumulation of neurotoxic soluble amyloid-beta oligomers and protofibrils. In addition, DAI initiates unique proteome profiles different from that of focal TBI in structurally normal-appearing brain. These findings have implication for the clinical management of DAI patients, and provide new insight in the neuropathological consequences of axonal injury.
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| 7. |
- Ahmed, Degmo Said, et al.
(författare)
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Quantitative determination of cerebrospinal fluid bilirubin on a high throughput chemistry analyzer
- 2009
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Ingår i: Clinical laboratory. - 1433-6510. ; 55:7-8, s. 283-288
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subarachnoid hemorrhage is a condition with high rates of mortality and morbidity. The diagnosis requires an urgent cerebral computed tomography scan and also a lumbar puncture if the scan fails to demonstrate intracranial blood. In Sweden the cerebrospinal fluid (CSF) is analyzed by spectrophotometric scanning for the presence of hemoglobin and bilirubin. The aim of the study was to develop a quantitative diazo reagent based analysis of cerebrospinal fluid bilirubin as a replacement for spectrophotometric scanning. METHODS: The CSF bilirubin assay on an Architect C8000 chemistry analyzer was compared with spectrophotometry using patient samples. RESULTS: The method correlates with spectrophotometry, has a good linearity and precision. CONCLUSIONS: Quantitative bilirubin measurement offers shorter turnaround times, simplifies the interpretation of the results and reduces work load in comparison with spectrophotometry.
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| 8. |
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| 9. |
- Clausen, Fredrik, 1973-, et al.
(författare)
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Acute Inflammatory Biomarker Responses to Diffuse Traumatic Brain Injury in the Rat Monitored by a Novel Microdialysis Technique
- 2019
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 36:2, s. 201-211
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Tidskriftsartikel (refereegranskat)abstract
- Neuroinflammation is a major contributor to the progressive brain injury process induced by traumatic brain injury (TBI), and may play an important role in the pathophysiology of axonal injury. The immediate neuroinflammatory cascade cannot be characterized in the human setting. Therefore, we used the midline fluid percussion injury model of diffuse TBI in rats and a novel microdialysis (MD) method providing stable diffusion-driven biomarker sampling. Immediately post-injury, bilateral amphiphilic tri-block polymer coated MD probes (100 kDa cut off membrane) were inserted and perfused with Dextran 500 kDa-supplemented artificial cerebrospinal fluid (CSF) to optimize protein capture. Six hourly samples were analyzed for 27 inflammatory biomarkers (9 chemokines, 13 cytokines, and 5 growth factors) using a commercial multiplex biomarker kit. TBI (n = 6) resulted in a significant increase compared with sham-injured controls (n = 6) for five chemokines (eotaxin/CCL11, fractalkine/CX3CL1, LIX/CXCL5, monocyte chemoattractant protein [MCP]1α/CCL2, macrophage inflammatory protein [MIP]1α /CCL3), 10 cytokines (interleukin [IL]-1α, IL-1β, IL-4, IL-6, IL-10, IL-13, IL-17α, IL-18, interferon [IFN]-γ, tumor necrosis factor [TNF]-α), and four growth factors (epidermal growth factor [EGF], granulocyte-macrophage colony-stimulating factor [GM-CSF], leptin, vascular endothelial growth factor [VEGF]). Therefore, diffuse TBI was associated with an increased level of 18 of the 27 inflammatory biomarkers at one through six time points, during the observation period whereas the remaining 9 biomarkers were unaltered. The study shows that diffuse TBI induces an acute increase in a number of inflammatory biomarkers. The novel MD technique provides stable MD sampling suitable for further studies on the early neuroinflammatory cascade in TBI.
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| 10. |
- Clausen, Fredrik, et al.
(författare)
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Cerebral glucose metabolism after traumatic brain injury in the rat studied by C-13-glucose and microdialysis
- 2011
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 153:3, s. 653-658
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Tidskriftsartikel (refereegranskat)abstract
- Following traumatic brain injury (TBI), a disturbed cerebral glucose metabolism contributes to secondary brain damage. To study local cerebral glucose metabolism after TBI, we delivered C-13-labeled glucose into brain tissue by microdialysis (MD). MD probes were inserted bilaterally into the parietal cortex of rat brain, one probe in the shear stress zone of the injury and the other at the corresponding contralateral coordinates. A moderately severe controlled cortical contusion was used to model TBI. Dialysate concentrations of glucose, pyruvate, lactate, and glycerol were measured, and following derivatization, C-13 enrichments of the compounds were determined by gas chromatography-mass spectrometry. We found that C-13-labeled glucose was rapidly converted into C-13-lactate and C-13-glycerol. In the hours following TBI, concentrations and C-13 enrichments of lactate and glycerol increased. The findings confirm the occurrence of anaerobic local glucose metabolism early after TBI. Only a small fraction of the glycerol was newly synthesized, suggesting that the hypothesis that most of the released glycerol after TBI comes from degradation of membrane phospholipids still holds. We conclude that the combination of microdialysis and stable isotope technique is a useful tool for investigating local glucose metabolism following brain injury.
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| 11. |
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| 12. |
- Clausen, Fredrik, 1973-
(författare)
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Delayed Cell Death after Traumatic Brain Injury : Role of Reactive Oxygen Species
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI) is a leading cause of death and disability TBI survivors often suffer from severe disturbances of cognition, memory and emotions. Improving the treatment is of great importance, but as of yet no specific neuroprotective treatment has been found. After TBI there are changes in ion homeostasis and protein regulation, causing generation of reactive oxygen species (ROS). Overproduction of ROS can lead to damage cellmembranes, proteins and DNA and secondary cell death. In the present thesis experimental TBI in rats were used to study the effects of the ROS scavengers α-phenyl-N-tert-butyl-nitrone (PBN) and 2-sulfophenyl-N-tert-butyl-nitrone (S-PBN) on morphology, function, intracellular signalling and apoptosis. Posttreatment with PBN and S-PBN resulted in attenuation of tissue loss after TBI and S-PBN improved cognitive function evaluated in the Morris water maze (MWM). Pretreatment with PBN protected hippocampal morphology, which correlated to better MWM-performance after TBI.To detect ROS-generation in vivo, a method using 4-hydroxybenzoic acid (4-HBA) microdialysis in the injured cortex was refined. 4-HBA reacts with ROS to form 3,4-DHBA, which can be quantified using HPLC, revealing that ROS-formation was increased for 90 minutes after TBI. It was possible to attenuate the formation significantly with PBN and S-PBN treatment. The activation of extracellular signal-regulated kinase (ERK) is generally considered beneficial for cell survival. However, persistent ERK activation was found in the injured cortex after TBI, coinciding with apoptosis-like cell death 24 h after injury. Pretreatment with the MEK-inhibitor U0126 and S-PBN significantly decreased ERK activation and reduced apoptosis-like cell death. Posttreatment with U0126 or S-PBN showed robust protection of cortical tissue.To conclude: ROS-mediated mechanisms play an important role in secondary cell death following TBI. The observed effects of ROS in intracellular signalling may be important for defining new targets for neuroprotective intervention.
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| 13. |
- Clausen, Fredrik, et al.
(författare)
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Interstitial F2-Isoprostane 8-Iso-PGF2α As a Biomarker of Oxidative Stress after Severe Human Traumatic Brain Injury
- 2012
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 29:5, s. 766-775
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress is a major contributor to the secondary injury process after experimental traumatic brain injury (TBI). The importance of oxidative stress in the pathobiology of human TBI is largely unknown. The F(2)-isoprostane 8-iso-prostaglandin F(2α) (8-iso-PGF(2α)), synthesized in vivo through non-enzymatic free radical catalyzed peroxidation of arachidonic acid, is a widely used biomarker of oxidative stress in multiple disease states, including TBI and cerebral ischemia/reperfusion. Our hypothesis is that harvesting of biomarkers directly in the injured brain by cerebral microdialysis (MD) is advantageous because of its high spatial and temporal resolution compared to blood or cerebrospinal fluid sampling. The aim of this study was to test the feasibility of measuring 8-iso-PGF(2α) in MD, ventricular cerebrospinal fluid (vCSF), and plasma samples collected from patients with severe TBI, and to compare the MD signals with MD-glycerol, implicated as a biomarker of oxidative stress, as well as MD-glutamate, a biomarker of excitotoxicity. Six patients (4 men, 2 women) were included in the study, three of whom had a focal/mixed TBI, and three a diffuse axonal injury (DAI). Following the bedside analysis of routine MD biomarkers (glucose, lactate:pyruvate ratio, glycerol, and glutamate), two 12-h MD samples per day were used to analyze 8-iso-PGF(2α) from 24 h up to 8 days post-injury. The interstitial levels of 8-iso-PGF(2α) were markedly higher than the levels obtained from plasma and vCSF (p<0.05), supporting our hypothesis. The MD-8-iso-PGF(2α) levels correlated strongly (p<0.05) with MD-glycerol and MD-glutamate, which are widely used biomarkers of membrane phospholipid degradation/oxidative stress and excitotoxicity, respectively. This study demonstrates the feasibility of analyzing 8-iso-PGF(2α) in MD samples from the human brain. Our results support a close relationship between oxidative stress and excitotoxicity following human TBI. MD-8-iso-PGF(2α) in combination with MD-glycerol may be useful biomarkers of oxidative stress in the neurointensive care setting.
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| 14. |
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| 15. |
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| 16. |
- Clausen, Fredrik, et al.
(författare)
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Neutralization of interleukin-1β modifies the inflammatory response and improves histological and cognitive outcome following traumatic brain injury in mice
- 2009
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Ingår i: European Journal of Neuroscience. - : Federation of European Neuroscience Societies and Blackwell Publishing Ltd. - 0953-816X .- 1460-9568. ; 30:3, s. 385-396
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-1beta (IL-1beta) may play a central role in the inflammatory response following traumatic brain injury (TBI). We subjected 91 mice to controlled cortical impact (CCI) brain injury or sham injury. Beginning 5 min post-injury, the IL-1beta neutralizing antibody IgG2a/k (1.5 microg/mL) or control antibody was infused at a rate of 0.25 microL/h into the contralateral ventricle for up to 14 days using osmotic minipumps. Neutrophil and T-cell infiltration and microglial activation was evaluated at days 1-7 post-injury. Cognition was assessed using Morris water maze, and motor function using rotarod and cylinder tests. Lesion volume and hemispheric tissue loss were evaluated at 18 days post-injury. Using this treatment strategy, cortical and hippocampal tissue levels of IgG2a/k reached 50 ng/mL, sufficient to effectively inhibit IL-1betain vitro. IL-1beta neutralization attenuated the CCI-induced cortical and hippocampal microglial activation (P < 0.05 at post-injury days 3 and 7), and cortical infiltration of neutrophils (P < 0.05 at post-injury day 7). There was only a minimal cortical infiltration of activated T-cells, attenuated by IL-1beta neutralization (P < 0.05 at post-injury day 7). CCI induced a significant deficit in neurological motor and cognitive function, and caused a loss of hemispheric tissue (P < 0.05). In brain-injured animals, IL-1beta neutralizing treatment resulted in reduced lesion volume, hemispheric tissue loss and attenuated cognitive deficits (P < 0.05) without influencing neurological motor function. Our results indicate that IL-1beta is a central component in the post-injury inflammatory response that, in view of the observed positive neuroprotective and cognitive effects, may be a suitable pharmacological target for the treatment of TBI.
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| 17. |
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| 18. |
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| 19. |
- Clausen, Fredrik, et al.
(författare)
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Oxygen free radical-dependent activation of extracellular signal-regulated kinase mediates apoptosis-like cell death after traumatic brain injury
- 2004
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Ingår i: Journal of Neurotrauma. ; 21:9, s. 1168-1182
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Tidskriftsartikel (refereegranskat)abstract
- Mitogen-activated protein kinase (MAPK) cascades are membrane-to-nucleus signaling modules that recently have been implicated as mediators of cellular injury. In this study, we investigated the involvement of the MAP kinase p44/p42 (extracellular signal-regulated kinase [ERK1/2]) in traumatic brain injury (TBI) in rats. There was a strong increase in activated, phosphorylated ERK 1/2 (p-ERK 1/2) protein at 10 min up to 24 h after the injury. Expression of p-ERK occurred in cells identified as neurons, astrocytes, and microglia. Most of the cells expressing p-ERK were TUNEL positive at later time points. Treatment with the MEK inhibitor U0126 or the free radical scavenger S-PBN, both with neuroprotective properties in TBI, attenuated the early activation of ERK and resulted in less activation of caspase-3 and subsequent DNA fragmentation. Post-treatment with U0126 resulted in a significant decrease (-60%) in cortical cavity size and cortical atrophy at 2 weeks after trauma. Overall, the results suggest that ERK activation is initiated by increased oxygen radical activity and that overactivation of ERK sets off secondary cell death mechanisms in TBI. Clinical studies are warranted to evaluate the concept of MEK inhibition in head-injured patients.
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| 20. |
- Clausen, Fredrik, et al.
(författare)
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T Lymphocyte trafficking : A novel target for neuroprotection in traumatic brain injury
- 2007
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 24:8, s. 1295-1307
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Tidskriftsartikel (refereegranskat)abstract
- Infiltration of T lymphocytes is a key feature in transplant rejection and in several autoimmune disorders, but the role of T lymphocytes in traumatic brain injury (TBI) is largely unknown. Here we studied trafficking of immune cells in the brain after experimental TBI. We found that scavenging of reactive oxygen species (ROS) at the endothelial level dramatically reduced the infiltration of activated T lymphocytes. Immune cell infiltration was studied 12 h to 7 days after controlled cortical contusion in rats by ex vivo propagation of T lymphocytes (TcR+, CD8+), neutrophils (MPO+), and macrophages/microglia (ED-1+) from biopsies taken from injured cortex and analyzed by flow cytometry, as well as by quantitative immunohistochemistry. T lymphocyte and neutrophil infiltration peaked at 24 h and macrophages/microglia at 7 days post-injury. Pretreatment with 2-sulfophenyl-N-tert-butyl nitrone (S-PBN) produced a dramatic reduction of TcR+ T lymphocytes and a significantly smaller attenuation of neutrophil infiltration at 24 h post-injury, but did not affect CD8+ T lymphocytes or macrophages/microglia. S-PBN significantly reduced the expression of the endothelial adhesion molecules ICAM-1 and VCAM at 24 h for following TBI. We conclude that ROS inhibition at the endothelial level influenced T lymphocyte and neutrophil infiltration following TBI. We submit that the reduction of T lymphocyte infiltration is a key feature in improving TBI outcome after S-PBN treatment. Our data suggest that targeting T lymphocyte trafficking to the injured brain at the microvascular level is a novel concept of neuroprotection in TBI and warrants further exploration.
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| 21. |
- Clausen, Fredrik, et al.
(författare)
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The Fluid Percussion Injury Rodent Model in Preclinical Research on Traumatic Brain Injury
- 2019
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Ingår i: Animal Models of Neurotrauma. - New York, NY : Springer New York. - 0893-2336 .- 1940-6045. - 9781493997091 - 9781493997114 ; 149, s. 3-18
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Bokkapitel (refereegranskat)abstract
- There is still a lack of pharmacological treatment options for traumatic brain injury (TBI), the dominant cause of death and disability in persons under the age of 40 in the developed part of the world. Clinical TBI is a markedly complex disease, categorized into different subtypes that differ in their pathophysiology, treatment requirements, and long-term consequences. For successful development of novel treatment options, refined preclinical evaluation in rodent TBI models is mandatory. Since persisting cognitive deficits, impaired motor function, depression, and personality changes are common sequelae in TBI patients, preclinical models must produce clinically relevant behavioral deficits. Additionally, clinical TBI is a markedly heterogeneous disease with a severity span from immediately fatal to mild injuries with minor and passing symptoms. Ideally, a rodent TBI model should thus be adjustable in terms of injury severity. One of the most widely used rodent TBI model is the fluid percussion injury (FPI), which meets many of the criteria for a clinically relevant experimental model. The FPI technique relies on a fluid pressure pulse being transmitted into the skull cavity of the animal, allowing for a degree of brain displacement. By placing the craniectomy and the injury site either over the midline of the skull (the central FPI; cFPI) or over one hemisphere (the lateral FPI; lFPI) the injury shows either more diffuse (cFPI) or more focal (lFPI) characteristics. Although FPI has many advantages over other TBI models, including the possibility to vary important injury characteristics, the outcome after TBI may be influenced by other features such as gender, age, species, and even strain which should be considered in the design of the rodent models. In this chapter, we discuss the limitations and advantages, as well as the special considerations necessary when using the FPI model in rodents.
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| 22. |
- Clausen, Fredrik, 1973-, et al.
(författare)
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The nitrone free radical scavenger NXY-059 is neuroprotective when administered after traumatic brain injury in the rat
- 2008
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert, Inc.. - 0897-7151 .- 1557-9042. ; 25:12, s. 1449-1457
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Tidskriftsartikel (refereegranskat)abstract
- Reactive oxygen species (ROS) are important contributors to the secondary injury cascade following traumatic brain injury (TBI), and ROS inhibition has consistently been shown to be neuroprotective following experimental TBI. NXY-059, a nitrone free radical trapping compound, has been shown to be neuroprotective in models of ischemic stroke but has not been evaluated in experimental TBI. In the present study, a continuous 24-h intravenous infusion of NXY-059 or vehicle was initiated 30min following a severe lateral fluid percussion brain injury (FPI) in adult rats (n=22), and histological and behavioral outcomes were evaluated. Sham-injured animals (n=22) receiving identical drug infusion were used as controls. Visuospatial learning was evaluated in the Morris water maze at post-injury days 11–14, followed by a probe trial (memory test) at day 18. The animals were sacrificed at day 18, and loss of hemispheric brain tissue was measured in microtubule-associated protein (MAP)–2stained sections. Brain-injured, NXY-059-treated animals showed a significant reduction of visuospatial learning deficits when compared to the brain-injured, vehicle-treated control animals (p<0.05). NXY-059-treated animals significantly reduced the loss of hemispheric tissue compared to brain-injured controls (43.0±11mm3 versus 74.4±19mm3, respectively; p<0.01). The results show that post-injury treatment with NXY-059 significantly attenuated the loss of injured brain tissue and improved cognitive outcome, suggesting a major role for ROS in the pathophysiology of TBI.
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| 23. |
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| 24. |
- Dahlin, Andreas P., et al.
(författare)
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Methodological aspects on microdialysis protein sampling and quantification in biological fluids : an in vitro study on human ventricular CSF.
- 2010
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 82:11, s. 4376-4385
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Tidskriftsartikel (refereegranskat)abstract
- There is growing interest in sampling of protein biomarkers from the interstitial compartment of the brain and other organs using high molecular cutoff membrane microdialysis (MD) catheters. However, recent data suggest that protein sampling across such MD membranes is a highly complex process that needs to be further studied. Here, we report three major improvements for microdialysis sampling of proteins in complex biological matrixes. The improvements in this in vitro study using human ventricular cerebrospinal fluid as the sample matrix include increased fluid recovery control, decreased protein adsorption on the microdialysis membrane and materials, and novel quantitative mass spectrometry analysis. Dextrans in different concentrations and sizes were added to the perfusion fluid. It was found that dextrans with molecular mass 250 and 500 kDa provided a fluid recovery close to 100%. An improved fluid recovery precision could be obtained by self-assembly triblock polymer surface modification of the MD catheters. The modified catheters also delivered a significantly increased extraction efficiency for some of the investigated proteins. The final improvement was to analyze the dialysates with isobaric tagged (iTRAQ) proteomics, followed by tandem mass spectrometric analysis. By using this technique, 48 proteins could be quantified and analyzed with respect to their extraction efficiencies. The novel aspects of microdialysis protein sampling, detection, and quantification in biological fluids presented in this study should be considered as a first step toward better understanding and handling of the challenges associated with microdialysis sampling of proteins. The next step is to optimize the developed methodology in vivo.
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| 25. |
- Dahlin, Andreas P, et al.
(författare)
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Multiplexed quantification of proteins adsorbed to surface-modified and non-modified microdialysis membranes
- 2012
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 402:6, s. 2057-2067
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Tidskriftsartikel (refereegranskat)abstract
- A simple and straightforward method for discovery and quantification of proteins adsorbed onto delicate and sensitive membrane surfaces is presented. The adsorbed proteins were enzymatically cleaved while still adsorbed onto the membranes using an on-surface enzymatic digestion (oSED). This was followed by isobaric tagging, nanoliquid chromatography, and tandem mass spectrometry. Protein adsorption on tri-block copolymer Poloxamer 407 surface-modified microdialysis (MD) membranes were compared with protein adsorption on unmodified MD membranes. Ventricular cerebrospinal fluid (vCSF) kept at 37 °C was used as sample matrix. In total, 19 proteins were quantified in two biological replicates. The surface-modified membranes adsorbed 33% less proteins than control membranes and the most abundant proteins were subunits of hemoglobin and clusterin. The adsorption of clusterin on the modified membranes was on average 36% compared to control membranes. The most common protein in vCSF, Albumin, was not identified adsorbed to the surface at all. It was also experimentally verified that oSED, in conjunction with tandem mass spectrometry can be used to quantify femtomole amounts of proteins adsorbed on limited and delicate surfaces, such as MD membranes. The method has great potential and can be used to study much more complex protein adsorption systems than previously reported.
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| 26. |
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| 27. |
- Dahlin, Andreas P, et al.
(författare)
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Refined microdialysis method for protein biomarker sampling in acute brain injury in the neurointensive care setting
- 2014
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 86:17, s. 8671-8679
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Tidskriftsartikel (refereegranskat)abstract
- There is growing interest in cerebral microdialysis (MD) for sampling of protein biomarkers in neurointensive care (NIC) patients. Published data point to inherent problems with this methodology including protein interaction and biofouling leading to unstable catheter performance. This study tested the in vivo performance of a refined MD method including catheter surface modification, for protein biomarker sampling in a clinically relevant porcine brain injury model. Seven pigs of both sexes (10-12 weeks old; 22.2-27.3 kg) were included. Mean arterial blood pressure, heart rate, intracranial pressure (ICP) and cerebral perfusion pressure was recorded during the stepwise elevation of intracranial pressure by inflation of an epidural balloon catheter with saline (1 mL/20 min) until brain death. One naïve MD catheter and one surface modified with Pluronic F-127 (10 mm membrane, 100 kDa molecular weight cutoff MD catheter) were inserted into the right frontal cortex and perfused with mock CSF with 3% Dextran 500 at a flow rate of 1.0 μL/min and 20 min sample collection. Naïve catheters showed unstable fluid recovery, sensitive to ICP changes, which was significantly stabilized by surface modification. Three of seven naïve catheters failed to deliver a stable fluid recovery. MD levels of glucose, lactate, pyruvate, glutamate, glycerol and urea measured enzymatically showed an expected gradual ischemic and cellular distress response to the intervention without differences between naïve and surface modified catheters. The 17 most common proteins quantified by iTRAQ and nanoflow LC-MS/MS were used as biomarker models. These proteins showed a significantly more homogeneous response to the ICP intervention in surface modified compared to naïve MD catheters with improved extraction efficiency for most of the proteins. The refined MD method appears to improve the accuracy and precision of protein biomarker sampling in the NIC setting.
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| 28. |
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| 29. |
- Dyhrfort, Philip, et al.
(författare)
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A Dedicated 21-Plex Proximity Extension Assay Panel for High-Sensitivity Protein Biomarker Detection Using Microdialysis in Severe Traumatic Brain Injury : The Next Step in Precision Medicine?
- 2023
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Ingår i: NEUROTRAUMA REPORTS. - : Mary Ann Liebert. - 2689-288X. ; 4:1, s. 25-40
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral protein profiling in traumatic brain injury (TBI) is needed to better comprehend secondary injury pathways. Cerebral microdialysis (CMD), in combination with the proximity extension assay (PEA) technique, has great potential in this field. By using PEA, we have previously screened >500 proteins from CMD samples collected from TBI patients. In this study, we customized a PEA panel prototype of 21 selected candidate protein biomarkers, involved in inflammation (13), neuroplasticity/-repair (six), and axonal injury (two). The aim was to study their temporal dynamics and relation to age, structural injury, and clinical outcome. Ten patients with severe TBI and CMD monitoring, who were treated in the Neurointensive Care Unit, Uppsala University Hospital, Sweden, were included. Hourly CMD samples were collected for up to 7 days after trauma and analyzed with the 21-plex PEA panel. Seventeen of the 21 proteins from the CMD sample analyses showed significantly different mean levels between days. Early peaks (within 48 h) were noted with interleukin (IL)-1 beta, IL-6, IL-8, granulocyte colony-stimulating factor, transforming growth factor alpha, brevican, junctional adhesion molecule B, and neurocan. C-X-C motif chemokine ligand 10 peaked after 3 days. Late peaks (>5 days) were noted with interleukin-1 receptor antagonist (IL-1ra), monocyte chemoattractant protein (MCP)-2, MCP-3, urokinase-type plasminogen activator, Dickkopf-related protein 1, and DRAXIN. IL-8, neurofilament heavy chain, and TAU were biphasic. Age (above/below 22 years) interacted with the temporal dynamics of IL-6, IL-1ra, vascular endothelial growth factor, MCP-3, and TAU. There was no association between radiological injury (Marshall grade) or clinical outcome (Extended Glasgow Outcome Scale) with the protein expression pattern. The PEA method is a highly sensitive molecular tool for protein profiling from cerebral tissue in TBI. The novel TBI dedicated 21-plex panel showed marked regulation of proteins belonging to the inflammation, plasticity/repair, and axonal injury families. The method may enable important insights into complex injury processes on a molecular level that may be of value in future efforts to tailor pharmacological TBI trials to better address specific disease processes and optimize timing of treatments.
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| 30. |
- Dyhrfort, Philip, et al.
(författare)
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Monitoring of Protein Biomarkers of Inflammation in Human Traumatic Brain Injury Using Microdialysis and Proximity Extension Assay Technology in Neurointensive Care
- 2019
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Ingår i: Journal of Neurotrauma. - : MARY ANN LIEBERT, INC. - 0897-7151 .- 1557-9042. ; 36:20, s. 2872-2885
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) is followed by secondary injury mechanisms strongly involving neuroinflammation. To monitor the complex inflammatory cascade in human TBI, we used cerebral microdialysis (MD) and multiplex proximity extension assay (PEA) technology and simultaneously measured levels of 92 protein biomarkers of inflammation in MD samples every three hours for five days in 10 patients with severe TBI under neurointensive care. One mu L MD samples were incubated with paired oligonucleotide-conjugated antibodies binding to each protein, allowing quantification by real-time quantitative polymerase chain reaction. Sixty-nine proteins were suitable for statistical analysis. We found five different patterns with either early (<48 h; e.g., CCL20, IL6, LIF, CCL3), mid (48-96 h; e.g., CCL19, CXCL5, CXCL10, MMP1), late (>96 h; e.g., CD40, MCP2, MCP3), biphasic peaks (e.g., CXCL1, CXCL5, IL8) or stable (e.g., CCL4, DNER, VEGFA)/low trends. High protein levels were observed for e.g., CXCL1, CXCL10, MCP1, MCP2, IL8, while e.g., CCL28 and MCP4 were detected at low levels. Several proteins (CCL8, -19, -20, -23, CXCL1, -5, -6, -9, -11, CST5, DNER, Flt3L, and SIRT2) have not been studied previously in human TBI. Cross-correlation analysis revealed that LIF and CXCL5 may play a central role in the inflammatory cascade. This study provides a unique data set with individual temporal trends for potential inflammatory biomarkers in patients with TBI. We conclude that the combination of MD and PEA is a powerful tool to map the complex inflammatory cascade in the injured human brain. The technique offers new possibilities of protein profiling of complex secondary injury pathways.
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| 31. |
- Ekmark Lewén, Sara, 1978-
(författare)
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Cellular Reactions and Behavioral Changes in Focal and Diffuse Traumatic Brain Injury : A Study in the Rat and Mouse
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI) is a severe condition and a major cause of death and disability. There is no pharmacological treatment available in clinical practice today and knowledge of brain injury mechanisms is of importance for development of neuroprotective drugs. The aims of the thesis were to get a better understanding of astrocyte reactions and immune responses, as well as behavioral changes after focal unilateral cortical contusion injury and diffuse bilateral central fluid percussion injury in rats and mice.In the focal injury models, the astrocyte reactions were generally restricted to the ipsilateral hemisphere. After diffuse TBI, vimentin and glial fibrillary acidic protein (GFAP) positive reactive astrocytes were bilaterally expressed in brain regions even distant from the injury site, including regions where axonal injury was seen. Early after diffuse TBI, there was a robust immune response, including activation of macrophages/microglia (Mac-2+) and infiltration of neutrophils (GR-1+) and T-cells (CD3+).In order to measure functional outcome, the recently established Multivariate Concentric Square Field™ (MCSF) test for complex behaviors, including risk taking and explorative strategies was used. The Morris water maze (MWM) was applied for testing learning and memory. The MCSF test revealed alterations in risk taking, risk assessment and exploratory behavior, in the mice subjected to focal injury whereas mice subjected to the diffuse injury showed a deviant stereotyped behavior. After focal injury mice showed a decreased ability to adapt to the arena in the second trial, when tested repeatedly in the MCSF test. Mice subjected to diffuse injury had an impaired memory but not learning, in the MWM test. Post-injury treatment with the anti-inflammatory anti-interleukin-1β (IgG2 a/k) antibody showed a positive effect on functional outcome in the diffuse injury model. Altogether, the results demonstrate that focal and diffuse TBI models produce differences in cellular reactions and behavioral outcome and that the immune response plays a key role in the pathology after brain injury.
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| 32. |
- Ekmark-Lewén, Sara, et al.
(författare)
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Diffuse traumatic axonal injury in mice induces complex behavioural alterations that are normalized by neutralization of interleukin-1β
- 2016
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Ingår i: European Journal of Neuroscience. - : Wiley. - 0953-816X .- 1460-9568. ; 43:8, s. 1016-1033
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Tidskriftsartikel (refereegranskat)abstract
- Widespread traumatic axonal injury (TAI) results in brain network dysfunction, which commonly leads to persisting cognitive and behavioural impairments following traumatic brain injury (TBI). TBI induces a complex neuroinflammatory response, frequently located at sites of axonal pathology. The role of the pro-inflammatory cytokine interleukin (IL)-1 has not been established in TAI. An IL-1-neutralizing or a control antibody was administered intraperitoneally at 30min following central fluid percussion injury (cFPI), a mouse model of widespread TAI. Mice subjected to moderate cFPI (n=41) were compared with sham-injured controls (n=20) and untreated, naive mice (n=9). The anti-IL-1 antibody reached the target brain regions in adequate therapeutic concentrations (up to similar to 30g/brain tissue) at 24h post-injury in both cFPI (n=5) and sham-injured (n=3) mice, with lower concentrations at 72h post-injury (up to similar to 18g/g brain tissue in three cFPI mice). Functional outcome was analysed with the multivariate concentric square field (MCSF) test at 2 and 9days post-injury, and the Morris water maze (MWM) at 14-21days post-injury. Following TAI, the IL-1-neutralizing antibody resulted in an improved behavioural outcome, including normalized behavioural profiles in the MCSF test. The performance in the MWM probe (memory) trial was improved, although not in the learning trials. The IL-1-neutralizing treatment did not influence cerebral ventricle size or the number of microglia/macrophages. These findings support the hypothesis that IL-1 is an important contributor to the processes causing complex cognitive and behavioural disturbances following TAI.
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| 33. |
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| 34. |
- Ekmark-Lewén, Sara, et al.
(författare)
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The Multivariate Concentric Square Field Test Reveals Behavioral Profiles of Risk Taking, Exploration, and Cognitive Impairment in Mice Subjected to Traumatic Brain Injury
- 2010
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 27:9, s. 1643-1655
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for more efficient tests to evaluate functional outcome following experimental traumatic brain injury (TBI), reflecting deficits in cognitive, sensory, and motor functions that are seen in TBI patients. The Multivariate Concentric Square Field (TM) (MCSF) test is a relatively new behavioral model that measures exploration, risk taking, risk assessment, and shelter seeking, all of which are evolutionarily-conserved strategies for survival. The multivariate design enables scoring of different functional domains in a single test situation, with a free choice of optional environmental settings. Furthermore, repeated trials permits cognitive effects to be measured. In the present study, 11 anesthetized C57BL6 mice received controlled cortical injury (CCI) (0.5mm and 3.3 m/sec) over the right parietal cerebral cortex or sham surgery (n - 12). Naive mice (n 12) not subjected to any surgical procedure were also included. The animals were evaluated in the MCSF test at 2 and 7 days post-surgery, and behavioral profiles were analyzed. The results revealed differences in risk taking and explorative behavior between the sham animals and the animals subjected to trauma. Animals subjected to trauma were characterized by taking more risks and had a higher level of exploration activity, but they sought less shelter. Repeated exposure to the MCSF caused a general decrease in activity in the naive and sham group, while a more specific behavioral impairment was seen in injured mice, suggesting cognitive dysfunction. We submit that the MCSF test is a useful complementary tool for functional outcome evaluation in experimental TBI.
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| 35. |
- Ekmark-Lewén, Sara, et al.
(författare)
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Traumatic axonal injury in the mouse is accompanied by a dynamic inflammatory response, astroglial reactivity and complex behavioral changes
- 2013
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 10:1, s. 44-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundDiffuse traumatic axonal injury (TAI), a common consequence of traumatic brain injury, is associated with high morbidity and mortality. Inflammatory processes may play an important role in the pathophysiology of TAI. In the murine central fluid percussion injury (cFPI) TAI model, the neuroinflammatory and astroglial response and behavioral changes are unknown.MethodsTwenty cFPI-injured and nine sham-injured mice were used, and the neuroinflammatory and astroglial response was evaluated by immunohistochemistry at 1, 3 and 7 days post-injury. The multivariate concentric square field test (MCSF) was used to compare complex behavioral changes in mice subjected to cFPI (n = 16) or sham injury (n = 10). Data was analyzed using non-parametric statistics and principal component analysis (MCSF data).ResultsAt all post-injury time points, beta-amyloid precursor protein (beta-APP) immunoreactivity revealed widespread bilateral axonal injury and IgG immunostaining showed increased blood--brain barrier permeability. Using vimentin and glial fibrillary acidic protein (GFAP) immunohistochemistry, glial cell reactivity was observed in cortical regions and important white matter tracts peaking at three days post-injury. Only vimentin was increased post-injury in the internal capsule and only GFAP in the thalamus. Compared to sham-injured controls, an increased number of activated microglia (MAC-2), infiltrating neutrophils (GR-1) and T-cells (CD3) appearing one day after TAI (P<0.05 for all cell types) was observed in subcortical white matter. In the MCSF, the behavioral patterns including general activity and exploratory behavior differed between cFPI mice and sham-injured controls.ConclusionsTraumatic axonal injury in mice resulted in marked bilateral astroglial and neuroinflammatory responses and complex behavioral changes. The cFPI model in mice appears suitable for the study of injury mechanisms, including neuroinflammation, and the development of treatments targeting traumatic axonal injury.
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| 36. |
- Ekmark-Lewén, Sara, et al.
(författare)
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Vimentin and GFAP responses in astrocytes after contusion trauma to the murine brain
- 2010
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Ingår i: Restorative Neurology and Neuroscience. - 0922-6028 .- 1878-3627. ; 28:3, s. 311-321
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Astroglial responses after traumatic brain injury are difficult to detect with routine morphological methods. The aims for this study were to compare the temporal and spatial expression pattern of vimentin-and glial fibrillary acidic protein (GFAP) in a weight drop model of mild cerebral contusion injury in the rat. We also wanted to study the vimentin response with immunohistochemistry and vimentin mRNA RT-PCR analysis in severe cortical contusion injury produced by the controlled cortical impact in the mouse. Methods: Vimentin and GFAP immunohistochemistry (1day, 3 days and 7 days) combined with vimentin mRNA RT-PCR analysis (1 h, 4 h, 22 h, 3 days and 7 days) were used after experimental traumatic brain injury in the rat and mouse. Results: Increases in post-traumatic vimentin mRNA levels in the cortex and in the hippocampus appeared together with vimentin immunoreactivity in astrocytes in the perimeter of the cortical lesion, in the subcortical white matter and in the hippocampus starting at one day after severe trauma. GFAP immunostaining revealed hypertrophic astrocytes peaking at day 3 in the perifocal cortical region. There was no significant increase in GFAP immunoreactivity in the white matter in the rat. However, in the mouse there was a slight increase in the number of GFAP positive cells in this region, 3 days after trauma. Overall the pattern of vimentin immunoreactivity was very similar in the rat and mouse. Conclusions: Vimentin immunoreactivity was more sensitive than the GFAP staining method to demonstrate the distribution and time course of astrocyte reactions after a contusion injury, especially in the white matter distant from the cortical lesion.
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| 37. |
- Engquist, Henrik, et al.
(författare)
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CBF changes and cerebral energy metabolism during hypervolemia, hemodilution, and hypertension therapy in patients with poor-grade subarachnoid hemorrhage
- 2021
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Ingår i: Journal of Neurosurgery. - : Journal of Neurosurgery Publishing Group (JNSPG). - 0022-3085 .- 1933-0693. ; 134:2, s. 555-564
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Despite the multifactorial pathogenesis of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH), augmentation of cerebral blood flow (CBF) is still considered essential in the clinical management of DCI. The aim of this prospective observational study was to investigate cerebral metabolic changes in relation to CBF during therapeutic hypervolemia, hemodilution, and hypertension (HHH) therapy in poor-grade SAH patients with DCI.METHODS: CBF was assessed by bedside xenon-enhanced CT at days 0–3, 4–7, and 8–12, and the cerebral metabolic state by cerebral microdialysis (CMD), analyzing glucose, lactate, pyruvate, and glutamate hourly. At clinical suspicion of DCI, HHH therapy was instituted for 5 days. CBF measurements and CMD data at baseline and during HHH therapy were required for study inclusion. Non-DCI patients with measurements in corresponding time windows were included as a reference group.RESULTS: In DCI patients receiving HHH therapy (n = 12), global cortical CBF increased from 30.4 ml/100 g/min (IQR 25.1–33.8 ml/100 g/min) to 38.4 ml/100 g/min (IQR 34.2–46.1 ml/100 g/min; p = 0.006). The energy metabolic CMD parameters stayed statistically unchanged with a lactate/pyruvate (L/P) ratio of 26.9 (IQR 22.9–48.5) at baseline and 31.6 (IQR 22.4–35.7) during HHH. Categorized by energy metabolic patterns during HHH, no patient had severe ischemia, 8 showed derangement corresponding to mitochondrial dysfunction, and 4 were normal. The reference group of non-DCI patients (n = 11) had higher CBF and lower L/P ratios at baseline with no change over time, and the metabolic pattern was normal in all these patients.CONCLUSIONS: Global and regional CBF improved and the cerebral energy metabolic CMD parameters stayed statistically unchanged during HHH therapy in DCI patients. None of the patients developed metabolic signs of severe ischemia, but a disturbed energy metabolic pattern was a common occurrence, possibly explained by mitochondrial dysfunction despite improved microcirculation.
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| 38. |
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| 39. |
- Fridgeirsdottir, Gudrun Andrea, et al.
(författare)
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Escalated handling of young C57BL/6 mice results in altered Morris water maze performance
- 2014
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 119:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background. The handling of experimental animals prior to experimental interventions is often poorly described, even though it may affect the final functional outcome. This study explores how the use of repeated handling of C57BL/6 mice prior to Morris water maze (MWM) tests can affect the performance. Methods and materials. The handled animals were subjected to the escalating handling protocol, with the investigator spending 5 min per day per cage for 8 days prior to the MWM test. On the last days of handling, the mice were introduced to water and the concept of a hidden platform. The MWM test consisted of four daily trials for 90 s per day for 4 days with a hidden platform. A probe test was performed 4 days after the last learning trial. Control animals were not handled prior to MWM. Results. Handling reduced the latency to find the platform on the first 2 days of the MWM tests and reduced thigmotaxis. The mice increased their swim speed and elicited more explorative behavior in the learning trials and to some lesser extent in the probe trials. Conclusions. The improvement in MWM navigation was most likely due to reduced stress and anxiety regarding the investigator and the test. Handled mice displayed less variability than non-handled mice, suggesting that by using a controlled handling protocol prior to the experiments fewer C57BL/6 mice would be needed to achieve statistically significant differences in studies of learning and spatial memory using MWM.
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| 40. |
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| 41. |
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| 42. |
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| 43. |
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| 44. |
- Hanrieder, Jörg, 1980, et al.
(författare)
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Temporally resolved differential proteomic analysis of human ventricular CSF for monitoring traumatic brain injury biomarker candidates.
- 2009
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Ingår i: Journal of neuroscience methods. - : Elsevier BV. - 0165-0270 .- 1872-678X. ; 177:2, s. 469-78
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Tidskriftsartikel (refereegranskat)abstract
- A shotgun proteomic approach based on nanoflow liquid chromatography (nanoLC) in conjunction with matrix assisted laser desorption/ionization time of flight tandem mass spectrometry (MALDI TOF MS/MS) was utilized to quantitatively analyze the protein content of consecutive ventricular cerebrospinal fluid (CSF) samples of severe traumatic brain injury (TBI) patients on an individual basis. CSF was acquired from the lateral ventricle 1-9 days after the TBI incident by canula drain to investigate temporally resolved protein changes in three patients that required intracranial pressure monitoring during neurointensive care. The samples were subjected to at once tryptic digestion followed by isobaric tag labeling before multiplexed peptide separation and MS analysis. By using this approach, we were able to follow characteristic changes in protein concentrations over time allowing new conclusions to be drawn about ongoing pathological processes during TBI. Certain suggested protein-biomarker candidates for TBI, like acute phase reactants (APRs), fibrinogens (FIB), cystatin C (CC) or more brain specific proteins like glial fibrillary acid protein (GFAP) and neuron-specific enolase (NSE) were found to be significantly up-regulated which is in strong consistence with previously reported results. This methodology appears to be a promising tool for studying candidate biomarkers of neurovascular and traumatic brain injuries in the neurointensive care setting.
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| 45. |
- Hillered, Lars, et al.
(författare)
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Cerebral microdialysis for protein biomarker monitoring in the neurointensive care setting - a technical approach
- 2014
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 5, s. 245-
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral microdialysis (MD) was introduced as a neurochemical monitoring method in the early 1990s and is currently widely used for the sampling of low molecular weight molecules, signaling energy crisis, and cellular distress in the neurointensive care (NIC) setting. There is a growing interest in MD for harvesting of intracerebral protein biomarkers of secondary injury mechanisms in acute traumatic and neurovascular brain injury in the NIC community. The initial enthusiasm over the opportunity to sample protein biomarkers with high molecular weight cut-off MD catheters has dampened somewhat with the emerging realization of inherent methodological problems including protein-protein interaction, protein adhesion, and biofouling, causing an unstable in vivo performance (i.e., fluid recovery and extraction efficiency) of the MD catheter. This review will focus on the results of a multidisciplinary collaborative effort, within the Uppsala Berzelii Centre for Neurodiagnostics during the past several years, to study the features of the complex process of high molecular weight cut-off MD for protein biomarkers. This research has led to new methodology showing robust in vivo performance with optimized fluid recovery and improved extraction efficiency, allowing for more accurate biomarker monitoring. In combination with evolving analytical methodology allowing for multiplex biomarker analysis in ultra-small MD samples, a new opportunity opens up for high-resolution temporal mapping of secondary injury cascades, such as neuroinflammation and other cell injury reactions directly in the injured human brain. Such data may provide an important basis for improved characterization of complex injuries, e.g., traumatic and neurovascular brain injury, and help in defining targets and treatment windows for neuroprotective drug development.
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| 46. |
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