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Xiao J, Qiu QW, Qin C, Tao R, Qiao SY, Chen M, Pan DJ, Tian DS. Dynamic changes of peripheral blood lymphocyte subsets in acute ischemic stroke and prognostic value. Brain Behav 2021; 11:e01919. [PMID: 33111494 PMCID: PMC7821621 DOI: 10.1002/brb3.1919] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To explore dynamic changes of peripheral blood lymphocyte subsets in patients with acute ischemic stroke (AIS) and the relationship with stroke severity and long-term outcomes. METHODS A total of 96 consecutive patients with AIS and 28 age- and gender-matched healthy controls were recruited. Peripheral blood samples were collected, and the percentages of lymphocyte subsets were analyzed by flow cytometry. The dynamic changes in lymphocyte subsets and their correlation with clinical parameters, such as National Institutes of Health Stroke Scale (NIHSS) scores at onset and modified Rankin scale (mRS) scores 3 months later, were evaluated. RESULTS In our study, we observed a decrease in the percentages of T-lymphocytes (T cells), helper/inducible T-lymphocytes (Th cells) and suppressor/cytotoxic T-lymphocytes (Ts cells) in AIS patients as compared to controls. The frequencies of T cells and Ts cells on day 8-14 after stroke in NIHSS ≤4 group were significantly higher than those in NIHSS >4 group. The percentages of T cells and Th cells on day 1-3 after stroke in the mRS ≤2 group were higher than those in the mRS >2 group. CONCLUSION The frequencies of T cells, Th cells, and Ts cells in AIS are declined dramatically at least 14 days after stroke. Lower frequencies of T cells and Ts cells on day 8-14 after stroke represent more severe disease conditions, and the percentages of T cells and Th cells within 72 hr after stroke are negatively correlated with 3-month outcomes, which might have a potential for predicting long-term prognosis of stroke.
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Affiliation(s)
- Jun Xiao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qian-Wen Qiu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chuan Qin
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ran Tao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Su-Ya Qiao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Man Chen
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Deng-Ji Pan
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dai-Shi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Joseph A, Liao R, Zhang M, Helmbrecht H, McKenna M, Filteau JR, Nance E. Nanoparticle-microglial interaction in the ischemic brain is modulated by injury duration and treatment. Bioeng Transl Med 2020; 5:e10175. [PMID: 33005740 PMCID: PMC7510458 DOI: 10.1002/btm2.10175] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022] Open
Abstract
Cerebral ischemia is a major cause of death in both neonates and adults, and currently has no cure. Nanotechnology represents one promising area of therapeutic development for cerebral ischemia due to the ability of nanoparticles to overcome biological barriers in the brain. ex vivo injury models have emerged as a high-throughput alternative that can recapitulate disease processes and enable nanoscale probing of the brain microenvironment. In this study, we used oxygen-glucose deprivation (OGD) to model ischemic injury and studied nanoparticle interaction with microglia, resident immune cells in the brain that are of increasing interest for therapeutic delivery. By measuring cell death and glutathione production, we evaluated the effect of OGD exposure time and treatment with azithromycin (AZ) on slice health. We found a robust injury response with 0.5 hr of OGD exposure and effective treatment after immediate application of AZ. We observed an OGD-induced shift in microglial morphology toward increased heterogeneity and circularity, and a decrease in microglial number, which was reversed after treatment. OGD enhanced diffusion of polystyrene-poly(ethylene glycol) (PS-PEG) nanoparticles, improving transport and ability to reach target cells. While microglial uptake of dendrimers or quantum dots (QDs) was not enhanced after injury, internalization of PS-PEG was significantly increased. For PS-PEG, AZ treatment restored microglial uptake to normal control levels. Our results suggest that different nanoparticle platforms should be carefully screened before application and upon doing so; disease-mediated changes in the brain microenvironment can be leveraged by nanoscale drug delivery devices for enhanced cell interaction.
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Affiliation(s)
- Andrea Joseph
- Department of Chemical EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Rick Liao
- Department of Chemical EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Mengying Zhang
- Molecular Engineering and Sciences InstituteUniversity of WashingtonSeattleWashingtonUSA
| | - Hawley Helmbrecht
- Department of Chemical EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Michael McKenna
- Department of Chemical EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Jeremy R. Filteau
- Department of Chemical EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Elizabeth Nance
- Department of Chemical EngineeringUniversity of WashingtonSeattleWashingtonUSA
- Molecular Engineering and Sciences InstituteUniversity of WashingtonSeattleWashingtonUSA
- Department of RadiologyUniversity of WashingtonSeattleWashingtonUSA
- eScience InstituteUniversity of WashingtonSeattleWashingtonUSA
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Intra-arterial Stem Cell Therapy Diminishes Inflammasome Activation After Ischemic Stroke: a Possible Role of Acid Sensing Ion Channel 1a. J Mol Neurosci 2019; 71:419-426. [PMID: 31820348 DOI: 10.1007/s12031-019-01460-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/29/2019] [Indexed: 12/19/2022]
Abstract
Studies from our lab demonstrated that 1 × 105 intra-arterial mesenchymal stem cells (IA MSCs) at 6 h following ischemic stroke are efficacious owing to its maximum homing due to elevated stromal derived factor 1 (SDF1) in the tissue. Further, IA MSCs could abate the infarct progression, improve functional outcome, and decrease expression of calcineurin by modifying neuronal Ca2+ channels following ischemic stroke. Since stroke pathology also encompasses acidosis that worsens the condition; hence, the role of acid sensing ion channels (ASICs) in this context could not be overlooked. ASIC1a being the major contributor towards acidosis triggers Ca2+ ions overload which progressively contributes towards exacerbation of neuronal injury following ischemic insult. Inflammasome involvement in ischemic stroke is well reported as activated ASIC1a increases the expression of inflammasome in a pH-dependent manner to trigger inflammatory cascade. Hence, the current study aimed to identify if IA MSCs can decrease the production of inflammasome by attenuating ASIC1a expression to render neuroprotection. Ovariectomized Sprague Dawley (SD) rats exposed to middle cerebral artery occlusion (MCAo) for 90 min were treated with phosphate-buffered saline (PBS) or 1 × 105 MSCs IA at 6 h to check for the expression of ASIC1a and inflammasome in different groups. Inhibition studies were carried out to explore the underlying mechanism. Our results demonstrate that IA MSCs improves functional outcome and oxidative stress parameters, and decreases the expression of ASIC1a and inflammasomes in the cortical brain region after ischemic stroke. This study offers a preliminary evidence of the role of IA MSCs in regulating inflammasome by modulating ASIC1a.
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Neuroprotective Effects of Musk of Muskrat on Transient Focal Cerebral Ischemia in Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:9817949. [PMID: 31341507 PMCID: PMC6614976 DOI: 10.1155/2019/9817949] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/11/2019] [Indexed: 11/18/2022]
Abstract
Musk of musk deer has been one of the most precious traditional medicinal materials for treatment of stroke, but trading is prohibited. Musk of muskrat, Ondatra zibethicus, is an accessible substitute for musk of musk deer. However, neuroprotective effects of the musk of muskrat on stroke model are so far unclear. Aim of the study is to determine neuroprotective effects of the musk of muskrat on focal cerebral ischemia. The protective effects against focal cerebral ischemia were evaluated using a model of middle cerebral artery occlusion (90-minute occlusion followed by 24-hour reperfusion). Musk of muskrat was collected from scent bag of muskrat and orally administered at doses of 100 and 300 mg/kg twice at times of 0 and 90 min after occlusion. The effects on sensorimotor dysfunction were investigated by using balance beam test and rotarod test after brain ischemia. The expression of cyclooxygenase-2 (COX-2) was investigated by immunohistochemistry. Oral administration of musk at 300 mg/kg significantly reduced (p<0.001) the infarct volume by 32.4% compared with a vehicle-treated group. Oral administration of musk at 300 mg/kg also ameliorated ischemia-induced spontaneous and vestibule sensorimotor dysfunction in balance beam test and rotarod test compared with control group and COX-2 upregulation. Musk of muskrat may have neuroprotective effects against transient focal cerebral ischemia with recovery of sensorimotor dysfunction. Regarding the immunohistochemistry, the effects of muskrat may be due to anti-inflammatory properties through inhibition of COX-2 expressions.
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Tyurenkov IN, Gumilevsky BY, Filina IS, Bakulin DA, Volotova EV, Kurkin DV. [The influence of the immunity activation and suppression on the outcome of brain ischemia]. Zh Nevrol Psikhiatr Im S S Korsakova 2015; 115:23-29. [PMID: 26525931 DOI: 10.17116/jnevro20151159223-29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
AIM To explore the influence of the immunity activation and suppression on the outcome of brain ischemia in experimental animals. MATERIAL AND METHODS Brain ischemia has been modulated by irreversible staged bilateral common carotid arteries occlusion. Suppression of the immune system has been conducted by administration of cyclosporin A (5 mg/kg, per os). Activation of the immune system has been conducted by administration of lipopolysaccharide (10 mkg/kg, i.p.). RESULTS Authors have established that in animals with immunosuppression there is an increase in the concentration of the neuron specific proteins in blood serum (NSE and MBP), mortality (by 20%) and severity of neurological deficit (by 33%). Rats with immunosuppression have reduced general locomotor activity (by 44%), exploratory behavior in the Open Field Test (by 43%) and decrease in the motor activity in the Rotarod Test (by 19%) compared to the group of rats with brain ischemia and intact immune systems. During the immunity activation after brain ischemia injury, the decrease in NSE and MBP levels, mortality (by 15%) and severity of neurological deficit (by 13%) as well as higher concentrations of neurotrophins BDNF and NGF and higher general locomotor activity of animals (by 34%) and physical endurance (by 55%) in the Open Field and Rotarod Tests, respectively, were observed. CONCLUSION Immunosupression negatively affected the outcome of brain ischemia.
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Affiliation(s)
| | | | - I S Filina
- Volgograd State Medical University, Volgograd
| | - D A Bakulin
- Volgograd State Medical University, Volgograd
| | | | - D V Kurkin
- Volgograd State Medical University, Volgograd
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Neumann J, Riek-Burchardt M, Herz J, Doeppner TR, König R, Hütten H, Etemire E, Männ L, Klingberg A, Fischer T, Görtler MW, Heinze HJ, Reichardt P, Schraven B, Hermann DM, Reymann KG, Gunzer M. Very-late-antigen-4 (VLA-4)-mediated brain invasion by neutrophils leads to interactions with microglia, increased ischemic injury and impaired behavior in experimental stroke. Acta Neuropathol 2015; 129:259-77. [PMID: 25391494 DOI: 10.1007/s00401-014-1355-2] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 10/08/2014] [Accepted: 10/08/2014] [Indexed: 12/17/2022]
Abstract
Neuronal injury from ischemic stroke is aggravated by invading peripheral immune cells. Early infiltrates of neutrophil granulocytes and T-cells influence the outcome of stroke. So far, however, neither the timing nor the cellular dynamics of neutrophil entry, its consequences for the invaded brain area, or the relative importance of T-cells has been extensively studied in an intravital setting. Here, we have used intravital two-photon microscopy to document neutrophils and brain-resident microglia in mice after induction of experimental stroke. We demonstrated that neutrophils immediately rolled, firmly adhered, and transmigrated at sites of endothelial activation in stroke-affected brain areas. The ensuing neutrophil invasion was associated with local blood-brain barrier breakdown and infarct formation. Brain-resident microglia recognized both endothelial damage and neutrophil invasion. In a cooperative manner, they formed cytoplasmic processes to physically shield activated endothelia and trap infiltrating neutrophils. Interestingly, the systemic blockade of very-late-antigen-4 immediately and very effectively inhibited the endothelial interaction and brain entry of neutrophils. This treatment thereby strongly reduced the ischemic tissue injury and effectively protected the mice from stroke-associated behavioral impairment. Behavioral preservation was also equally well achieved with the antibody-mediated depletion of myeloid cells or specifically neutrophils. In contrast, T-cell depletion more effectively reduced the infarct volume without improving the behavioral performance. Thus, neutrophil invasion of the ischemic brain is rapid, massive, and a key mediator of functional impairment, while peripheral T-cells promote brain damage. Acutely depleting T-cells and inhibiting brain infiltration of neutrophils might, therefore, be a powerful early stroke treatment.
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Bodhankar S, Chen Y, Vandenbark AA, Murphy SJ, Offner H. Treatment of experimental stroke with IL-10-producing B-cells reduces infarct size and peripheral and CNS inflammation in wild-type B-cell-sufficient mice. Metab Brain Dis 2014; 29:59-73. [PMID: 24374817 PMCID: PMC3944055 DOI: 10.1007/s11011-013-9474-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 12/16/2013] [Indexed: 12/11/2022]
Abstract
Clinical stroke induces inflammatory processes leading to cerebral and splenic injury and profound peripheral immunosuppression. IL-10 expression is elevated during major CNS diseases and limits inflammation in the brain. Recent evidence demonstrated that absence of B-cells led to larger infarct volumes and CNS damage after middle cerebral artery occlusion (MCAO) that could be prevented by transfer of IL-10(+) B-cells. The purpose of this study was to determine if the beneficial immunoregulatory effects on MCAO of the IL-10(+) B-cell subpopulation also extends to B-cell-sufficient mice that would better represent stroke subjects. CNS inflammation and infarct volumes were evaluated in male C57BL/6J (WT) mice that received either RPMI or IL-10(+) B-cells and underwent 60 min of middle cerebral artery occlusion (MCAO) followed by 96 h of reperfusion. Transfer of IL-10(+) B-cells markedly reduced infarct volume in WT recipient mice when given 24 h prior to or 4 h after MCAO. B-cell protected (24 h pre-MCAO) mice had increased regulatory subpopulations in the periphery, reduced numbers of activated, inflammatory T-cells, decreased infiltration of T-cells and a less inflammatory milieu in the ischemic hemispheres of the IL-10(+) B-cell-treated group. Moreover, transfer of IL-10(+) B-cells 24 h before MCAO led to a significant preservation of regulatory immune subsets in the IL-10(+) B-cell protected group presumably indicating their role in immunomodulatory mechanisms, post-stroke. Our studies are the first to demonstrate a major immunoregulatory role for IL-10(+) regulatory B-cells in preventing and treating MCAO in WT mice and also implicating their potential role in attenuating complications due to post-stroke immunosuppression.
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Affiliation(s)
- Sheetal Bodhankar
- Neuroimmunology Research, VA Medical Center, Portland, OR, USA
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Yingxin Chen
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Arthur A. Vandenbark
- Neuroimmunology Research, VA Medical Center, Portland, OR, USA
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, USA
| | - Stephanie J. Murphy
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Halina Offner
- Neuroimmunology Research, VA Medical Center, Portland, OR, USA
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
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Abstract
Inflammatory mechanisms contribute substantially to secondary tissue injury after brain ischemia. Regulatory T cells (Tregs) are key endogenous modulators of postischemic neuroinflammation. We investigated the potential of histone deacetylase inhibition (HDACi) to enhance Treg potency for experimental stroke in mice. HDACi using trichostatin A increased the number of Tregs and boosted their immunosuppressive capacity and interleukin (IL)-10 expression. In vivo treatment reduced infarct volumes and behavioral deficits after cortical brain ischemia, attenuated cerebral proinflammatory cytokine expression, and increased numbers of brain-invading Tregs. A similar effect was obtained using tubastatin, a specific inhibitor of HDAC6 and a key HDAC in Foxp3 regulation. The neuroprotective effect of HDACi depended on the presence of Foxp3(+) Tregs, and in vivo and in vitro studies showed that the anti-inflammatory cytokine IL-10 was their main mediator. In summary, modulation of Treg function by HDACi is a novel and potent target to intervene at the center of neuroinflammation. Furthermore, this novel concept of modulating endogenous immune mechanisms might be translated to a broad spectrum of diseases, including primary neuroinflammatory and neurodegenerative disorders.
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Barreto G, White RE, Ouyang Y, Xu L, Giffard RG. Astrocytes: targets for neuroprotection in stroke. Cent Nerv Syst Agents Med Chem 2012; 11:164-73. [PMID: 21521168 DOI: 10.2174/187152411796011303] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 02/05/2011] [Accepted: 03/09/2011] [Indexed: 02/08/2023]
Abstract
In the past two decades, over 1000 clinical trials have failed to demonstrate a benefit in treating stroke, with the exception of thrombolytics. Although many targets have been pursued, including antioxidants, calcium channel blockers, glutamate receptor blockers, and neurotrophic factors, often the focus has been on neuronal mechanisms of injury. Broader attention to loss and dysfunction of non-neuronal cell types is now required to increase the chance of success. Of the several glial cell types, this review will focus on astrocytes. Astrocytes are the most abundant cell type in the higher mammalian nervous system, and they play key roles in normal CNS physiology and in central nervous system injury and pathology. In the setting of ischemia astrocytes perform multiple functions, some beneficial and some potentially detrimental, making them excellent candidates as therapeutic targets to improve outcome following stroke and in other central nervous system injuries. The older neurocentric view of the central nervous system has changed radically with the growing understanding of the many essential functions of astrocytes. These include K+ buffering, glutamate clearance, brain antioxidant defense, close metabolic coupling with neurons, and modulation of neuronal excitability. In this review, we will focus on those functions of astrocytes that can both protect and endanger neurons, and discuss how manipulating these functions provides a novel and important strategy to enhance neuronal survival and improve outcome following cerebral ischemia.
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Affiliation(s)
- George Barreto
- Department of Anesthesia, Stanford University School of Medicine, S272, Stanford, CA 94305, USA
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Obrig H, Steinbrink J. Non-invasive optical imaging of stroke. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4470-94. [PMID: 22006902 DOI: 10.1098/rsta.2011.0252] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The acute onset of a neurological deficit is the key clinical feature of stroke. In most cases, however, pathophysiological changes in the cerebral vasculature precede the event, often by many years. Persisting neurological deficits may also require long-term rehabilitation. Hence, stroke may be considered a chronic disease, and diagnostic and therapeutic efforts must include identification of specific risk factors, and the monitoring of and interventions in the acute and subacute stages, and should aim at a pathophysiologically based approach to optimize the rehabilitative effort. Non-invasive optical techniques have been experimentally used in all three stages of the disease and may complement the established diagnostic and monitoring tools. Here, we provide an overview of studies using the methodology in the context of stroke, and we sketch perspectives of how they may be integrated into the assessment of the highly dynamic pathophysiological processes during the acute and subacute stages of the disease and also during rehabilitation and (secondary) prevention of stroke.
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Affiliation(s)
- Hellmuth Obrig
- Department of Cognitive Neurology, University Hospital Leipzig, Liebigstraße 16, 04103 Leipzig, Germany.
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Liesz A, Sun L, Zhou W, Schwarting S, Mracsko E, Zorn M, Bauer H, Sommer C, Veltkamp R. FTY720 reduces post-ischemic brain lymphocyte influx but does not improve outcome in permanent murine cerebral ischemia. PLoS One 2011; 6:e21312. [PMID: 21701599 PMCID: PMC3119049 DOI: 10.1371/journal.pone.0021312] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/25/2011] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The contribution of neuroinflammation and specifically brain lymphocyte invasion is increasingly recognised as a substantial pathophysiological mechanism after stroke. FTY720 is a potent treatment for primary neuroinflammatory diseases by inhibiting lymphocyte circulation and brain immigration. Previous studies using transient focal ischemia models showed a protective effect of FTY720 but did only partially characterize the involved pathways. We tested the neuroprotective properties of FTY720 in permanent and transient cortical ischemia and analyzed the underlying neuroimmunological mechanisms. METHODOLOGY/PRINCIPAL FINDINGS FTY720 treatment resulted in substantial reduction of circulating lymphocytes while blood monocyte counts were significantly increased. The number of histologically and flow cytometrically analyzed brain invading T- and B lymphocytes was significantly reduced in FTY720 treated mice. However, despite testing a variety of treatment protocols, infarct volume and behavioural dysfunction were not reduced 7d after permanent occlusion of the distal middle cerebral artery (MCAO). Additionally, we did not measure a significant reduction in infarct volume at 24 h after 60 min filament-induced MCAO, and did not see differences in brain edema between PBS and FTY720 treatment. Analysis of brain cytokine expression revealed complex effects of FTY720 on postischemic neuroinflammation comprising a substantial reduction of delayed proinflammatory cytokine expression at 3d but an early increase of IL-1β and IFN-γ at 24 h after MCAO. Also, serum cytokine levels of IL-6 and TNF-α were increased in FTY720 treated animals compared to controls. CONCLUSIONS/SIGNIFICANCE In the present study we were able to detect a reduction of lymphocyte brain invasion by FTY720 but could not achieve a significant reduction of infarct volumes and behavioural dysfunction. This lack of neuroprotection despite effective lymphopenia might be attributed to a divergent impact of FTY720 on cytokine expression and possible activation of innate immune cells after brain ischemia.
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Affiliation(s)
- Arthur Liesz
- Department of Neurology, University Heidelberg, Heidelberg, Germany.
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Elango C, Devaraj SN. Immunomodulatory effect of Hawthorn extract in an experimental stroke model. J Neuroinflammation 2010; 7:97. [PMID: 21192826 PMCID: PMC3022819 DOI: 10.1186/1742-2094-7-97] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 12/30/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recently, we reported a neuroprotective effect for Hawthorn (Crataegus oxyacantha) ethanolic extract in middle cerebral artery occlusion-(MCAO) induced stroke in rats. The present study sheds more light on the extract's mechanism of neuroprotection, especially its immunomodulatory effect. METHODS After 15 days of treatment with Hawthorn extract [100 mg/kg, pretreatment (oral)], male Sprague Dawley rats underwent transient MCAO for 75 mins followed by reperfusion (either 3 or 24 hrs). We measured pro-inflammatory cytokines (IL-1β, TNF-α, IL-6), ICAM-1, IL-10 and pSTAT-3 expression in the brain by appropriate methods. We also looked at the cytotoxic T cell sub-population among leukocytes (FACS) and inflammatory cell activation and recruitment in brain (using a myeloperoxidase activity assay) after ischemia and reperfusion (I/R). Apoptosis (TUNEL), and Bcl-xL- and Foxp3- (T(reg) marker) positive cells in the ipsilateral hemisphere of the brain were analyzed separately using immunofluorescence. RESULTS Our results indicate that occlusion followed by 3 hrs of reperfusion increased pro-inflammatory cytokine and ICAM-1 gene expressions in the ipsilateral hemisphere, and that Hawthorn pre-treatment significantly (p ≤ 0.01) lowered these levels. Furthermore, such pre-treatment was able to increase IL-10 levels and Foxp3-positive cells in brain after 24 hrs of reperfusion. The increase in cytotoxic T cell population in vehicle rats after 24 hrs of reperfusion was decreased by at least 40% with Hawthorn pretreatment. In addition, there was a decrease in inflammatory cell activation and infiltration in pretreated brain. Hawthorn pretreatment elevated pSTAT-3 levels in brain after I/R. We also observed an increase in Bcl-xL-positive cells, which in turn may have influenced the reduction in TUNEL-positive cells compared to vehicle-treated brain. CONCLUSIONS In summary, Hawthorn extract helped alleviate pro-inflammatory immune responses associated with I/R-induced injury, boosted IL-10 levels, and increased Foxp3-positive T(regs) in the brain, which may have aided in suppression of activated inflammatory cells. Such treatment also minimizes apoptotic cell death by influencing STAT-3 phosphorylation and Bcl-xL expression in the brain. Taken together, the immunomodulatory effect of Hawthorn extract may play a critical role in the neuroprotection observed in this MCAO-induced stroke model.
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Affiliation(s)
- Chinnasamy Elango
- Department of Biochemistry, University of Madras, Guindy Campus, Chennai-600 025, Tamil Nadu, India
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Kriz J, Lalancette-Hébert M. Inflammation, plasticity and real-time imaging after cerebral ischemia. Acta Neuropathol 2009; 117:497-509. [PMID: 19225790 DOI: 10.1007/s00401-009-0496-1] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 02/05/2009] [Accepted: 02/06/2009] [Indexed: 12/24/2022]
Abstract
With an incidence of approximately 350 in 100,000, stroke is the third leading cause of death and a major cause of disability in industrialized countries. At present, although progress has been made in understanding the molecular pathways that lead to ischemic cell death, the current clinical treatments remain poorly effective. There is mounting evidence that inflammation plays an important role in cerebral ischemia. Experimentally and clinically, brain response to ischemic injury is associated with an acute and prolonged inflammatory process characterized by the activation of resident glial cells, production of inflammatory cytokines as well as leukocyte and monocyte infiltration in the brain, events that may contribute to ischemic brain injury and affect brain recovery and plasticity. However, whether the post-ischemic inflammatory response is deleterious or beneficial to brain recovery is presently a matter of debate and controversies. Here, we summarize the current knowledge on the molecular mechanisms underlying post-ischemic neuronal plasticity and the potential role of inflammation in regenerative processes and functional recovery after stroke. Furthermore, because of the dynamic nature of the brain inflammatory response, we highlight the importance of the development of novel experimental approaches such as real-time imaging. Finally, we discuss the novel transgenic reporter mice models that have allowed us to visualize and to analyze the processes such as neuroinflammation and neuronal repair from the ischemic brains of live animals.
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Affiliation(s)
- Jasna Kriz
- Department of Anatomy and Physiology, Faculty of Medicine, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUQ), T3-67, Laval University, 2705 Boulevard Laurier, Quebec, QC, G1V 4G2, Canada.
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Liesz A, Suri-Payer E, Veltkamp C, Doerr H, Sommer C, Rivest S, Giese T, Veltkamp R. Regulatory T cells are key cerebroprotective immunomodulators in acute experimental stroke. Nat Med 2009; 15:192-9. [PMID: 19169263 DOI: 10.1038/nm.1927] [Citation(s) in RCA: 805] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 01/02/2009] [Indexed: 12/15/2022]
Abstract
Systemic and local inflammatory processes have a key, mainly detrimental role in the pathophysiology of ischemic stroke. Currently, little is known about endogenous counterregulatory immune mechanisms. We examined the role of the key immunomodulators CD4(+)CD25(+) forkhead box P3 (Foxp3)(+) regulatory T lymphocytes (T(reg) cells), after experimental brain ischemia. Depletion of T(reg) cells profoundly increased delayed brain damage and deteriorated functional outcome. Absence of T(reg) cells augmented postischemic activation of resident and invading inflammatory cells including microglia and T cells, the main sources of deleterious cerebral tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), respectively. Early antagonization of TNF-alpha and delayed neutralization of IFN-gamma prevented infarct growth in T(reg) cell-depleted mice. Intracerebral interleukin-10 (IL-10) substitution abrogated the cytokine overexpression after T(reg) cell depletion and prevented secondary infarct growth, whereas transfer of IL-10-deficient T(reg) cells in an adoptive transfer model was ineffective. In conclusion, T(reg) cells are major cerebroprotective modulators of postischemic inflammatory brain damage targeting multiple inflammatory pathways. IL-10 signaling is essential for their immunomodulatory effect.
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Affiliation(s)
- Arthur Liesz
- Department of Neurology, University Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
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Bechmann I. Failed central nervous system regeneration: a downside of immune privilege? Neuromolecular Med 2006; 7:217-28. [PMID: 16247182 DOI: 10.1385/nmm:7:3:217] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Accepted: 07/07/2005] [Indexed: 12/25/2022]
Abstract
Immunity is required to eliminate dangerous or degenerated material and to support regeneration, but also causes significant parenchymal damage. In the eye and the brain, in which cornea and lens poorly regenerate and neurons are hardly replaceable, early transplantation experiments demonstrated remarkable tolerance to various grafts. This "immunologically privileged status" (Billingham and Boswell, 1953) may reflect evolutionary pressure to downmodulate certain actions of immune cells within particularly vulnerable tissues. As an example, tolerating certain "neurotrophic" viruses may often be a more successful strategy for survival than the elimination of all infected neurons. While several constitutive and inducible signals maintaining or re-establishing immune tolerance within the brain have been identified, it has also become evident that the resulting anti-inflammatory environment limits certain beneficial effects of neuroinflammation such as neurotrophin secretion or glutamate buffering by T-cells and the clearance of growth-inhibiting myelin or amyloid. Following spinal cord injury, the costs and benefits of neuroinflammation seem to come close because enhancing as well as suppressing innate or adaptive immunity caused amelioration and aggravation of functional regeneration in similar experiments. Evaluating such balances has also begun in (animal models of) Alzheimer's disease, central nervous system trauma, and stroke, and the appreciation of the beneficial side of neuroinflammation has caused a rethinking of the ill-defined use of immune suppressants. As dual roles for individual molecules have been recognized (Merrill and Benveniste, 1996), we are uncovering an already fine-tuned system, but the challenge remains to further support beneficial immune cascades without causing additional damage, and vice versa.
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Affiliation(s)
- Ingo Bechmann
- Center for Anatomy, Institute of Cell Biology and Neurobiology, Department of Experimental Neuroimmunology, Charité-Universitätsmedizin Berlin, Schumannstr, 20/21 10098 Berlin, Germany.
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Thomas MS, Zhang W, Jordan PM, Saragovi HU, Taglialatela G. Signaling pathways mediating a selective induction of nitric oxide synthase II by tumor necrosis factor alpha in nerve growth factor-responsive cells. J Neuroinflammation 2005; 2:19. [PMID: 16144552 PMCID: PMC1242246 DOI: 10.1186/1742-2094-2-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 09/06/2005] [Indexed: 01/08/2023] Open
Abstract
Background Inflammation and oxidative stress play a critical role in neurodegeneration associated with acute and chronic insults of the nervous system. Notably, affected neurons are often responsive to and dependent on trophic factors such as nerve growth factor (NGF). We previously showed in NGF-responsive PC12 cells that tumor necrosis factor alpha (TNFα) and NGF synergistically induce the expression of the free-radical producing enzyme inducible nitric oxide synthase (iNOS). We proposed that NGF-responsive neurons might be selectively exposed to iNOS-mediated oxidative damage as a consequence of elevated TNFα levels. With the aim of identifying possible therapeutic targets, in the present study we investigated the signaling pathways involved in NGF/TNFα-promoted iNOS induction. Methods Western blotting, RT-PCR, transcription factor-specific reporter gene systems, mutant cells lacking the low affinity p75NTR NGF receptor and transfections of TNFα/NGF chimeric receptors were used to investigate signalling events associated with NGF/TNFα-promoted iNOS induction in PC12 cells. Results Our results show that iNOS expression resulting from NGF/TNFα combined treatment can be elicited in PC12 cells. Mutant PC12 cells lacking p75NTR did not respond, suggesting that p75NTR is required to mediate iNOS expression. Furthermore, cells transfected with chimeric TNFα/NGF receptors demonstrated that the simultaneous presence of both p75NTR and TrkA signaling is necessary to synergize with TNFα to mediate iNOS expression. Lastly, our data show that NGF/TNFα-promoted iNOS induction requires activation of the transcription factor nuclear factor kappa B (NF-κB). Conclusion Collectively, our in vitro model suggests that cells bearing both the high and low affinity NGF receptors may display increased sensitivity to TNFα in terms of iNOS expression and therefore be selectively at risk during acute (e.g. neurotrauma) or chronic (e.g. neurodegenerative diseases) conditions where high levels of pro-inflammatory cytokines in the nervous system occur pathologically. Our results also suggest that modulation of NFκB-promoted transcription of selective genes could serve as a potential therapeutic target to prevent neuroinflammation-induced neuronal damage.
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Affiliation(s)
- Michael S Thomas
- Department of Neuroscience and Cell Biology, the University of Texas Medical Branch at Galveston, Texas - USA
| | - WenRu Zhang
- Department of Neuroscience and Cell Biology, the University of Texas Medical Branch at Galveston, Texas - USA
| | - Paivi M Jordan
- Department of Neuroscience and Cell Biology, the University of Texas Medical Branch at Galveston, Texas - USA
| | - H Uri Saragovi
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Giulio Taglialatela
- Department of Neuroscience and Cell Biology, the University of Texas Medical Branch at Galveston, Texas - USA
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