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Brand-Schieber E, Werner P, Iacobas DA, Iacobas S, Beelitz M, Lowery SL, Spray DC, Scemes E. Connexin43, the major gap junction protein of astrocytes, is down-regulated in inflamed white matter in an animal model of multiple sclerosis. J Neurosci Res 2005; 80:798-808. [PMID: 15898103 PMCID: PMC1226319 DOI: 10.1002/jnr.20474] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Both multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), its animal model, involve inflammatory attack on central nervous system (CNS) white matter, leading to demyelination and axonal damage. Changes in astrocytic morphology and function are also prominent features of MS and EAE. Resting astrocytes form a network that is interconnected through gap junctions, composed mainly of connexin43 (Cx43) protein. Although astrocytic gap junctional connectivity is known to be altered in many CNS pathologies, little is known about Cx43 expression in inflammatory demyelinating disease. Therefore, we evaluated the expression of Cx43 in spinal cords of EAE mice compared with healthy controls. Lumbar ventral white matter areas were heavily infiltrated with CD11beta-immunoreactive monocytes, and within these infiltrated regions loss of Cx43 immunoreactivity was evident. These regions also showed axonal dystrophy, demonstrated by the abnormally dephosphorylated heavy-chain neurofilament proteins. Astrocytes in these Cx43-depleted lesions were strongly glial fibrillary acidic protein reactive. Significant loss (38%) of Cx43 protein in EAE mouse at the lumbar portion of spinal cords was confirmed by Western blot analysis. Decreased Cx43 transcript level was also observed on cDNA microarray analysis. In addition to changes in Cx43 expression, numerous other genes were altered, including those encoding adhesion and extracellular matrix proteins. Our data support the notion that, in addition to damage of myelinating glia, altered astrocyte connectivity is a prominent feature of inflammatory demyelination.
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Brand-Schieber E, Werner P. Calcium channel blockers ameliorate disease in a mouse model of multiple sclerosis. Exp Neurol 2004; 189:5-9. [PMID: 15296830 DOI: 10.1016/j.expneurol.2004.05.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Revised: 05/10/2004] [Accepted: 05/11/2004] [Indexed: 11/23/2022]
Abstract
Multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), an animal model of MS, are inflammatory demyelinating diseases of the central nervous system. The inflammatory attacks lead to glial dysfunction and death, axonal damage, and neurological deficits. Numerous studies in rat suggest that extracellular calcium influx, via voltage-gated calcium channels (VGCC), contributes to white matter damage in acute spinal cord injury and stroke. Our immunohistochemical finding that mouse spinal cord axons display subunits of L-type VGCC also supports this hypothesis. Furthermore, we hypothesized that VGCC also play a role in EAE, and possibly, MS. In our study, administration of the calcium channel blockers (CCB) bepridil and nitrendipine significantly ameliorated EAE in mice, compared with vehicle-treated controls. Spinal cord samples showed reduced inflammation and axonal pathology in bepridil-treated animals. Our data support the hypothesis that calcium influx via VGCC plays a significant role in the development of neurological disability and white matter damage in EAE and MS.
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Erälinna JP, Soilu-Hänninen M, Röyttä M, Hukkanen V, Salmi AA, Salonen R. Blood-brain barrier breakdown and increased intercellular adhesion molecule (ICAM-1/CD54) expression after Semliki Forest (A7) virus infection facilitates the development of experimental allergic encephalomyelitis. J Neuroimmunol 1996; 66:103-14. [PMID: 8964903 DOI: 10.1016/0165-5728(96)00031-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This report describes two mechanisms by which virus infection can facilitate demyelinating autoimmune inflammation in the murine CNS. In the BALB/c mouse model of experimental allergic encephalomyelitis (EAE), peripheral infection with an avirulent strain (A7) of Semliki Forest virus (SFV) increased the morbidity to EAE by infecting endothelial cells and damaging the blood-brain barrier (BBB). An influx of hematogenous CD18+ (LFA-1+ and MAC-1+) cells into the CNS compartment was followed by a local increase in intercellular adhesion molecule 1 (ICAM-1) expression on the vascular endothelium. Although SFV A7 infection without EAE induction caused multifocal cerebral vascular endothelial cell infection and BBB damage followed by cellular infiltration and transient increase of ICAM-1, inflammation and demyelination of CNS white matter with classical clinical signs of EAE was observed only in EAE-induced BALB/c mice, whereas the control mice remained neurologically healthy. The upregulation of ICAM-1 after virus infection was detected after the CD18+ (LFA-1+ and MAC-1+) cells had infiltrated the CNS both after EAE induction and also in nonsensitized control mice. The observed increase in ICAM-1 expression was transient in nonsensitized SFV A7 infected mice just as in the cellular infiltrates in the CNS, but EAE induction resulted in prolongation in both the cellular infiltrates and upregulation of ICAM-1. Thus, SFV A7 infection causes BBB damage and prolongs increased ICAM-1 expression on brain endothelium. This results in increased and more rapid morbidity to EAE in mice which have been sensitized with neuroantigen. However, SFV A7-infected mice without neuroantigen sensitization remain neurologically healthy.
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Affiliation(s)
- J P Erälinna
- Department of Virology, University of Turku, Finland.
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Duckers HJ, van Dokkum RP, Verhaagen J, Lopes da Silva FH, Gispen WH. Functional and neurophysiological evidence of the efficacy of trophic pharmacotherapy using an adrenocorticotrophic hormone4-9 analog in experimental allergic encephalomyelitis, an animal model of multiple sclerosis. Neuroscience 1996; 71:507-21. [PMID: 9053803 DOI: 10.1016/0306-4522(95)00451-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Chronic experimental allergic encephalomyelitis (CEAE) is a well-established animal model for the human syndrome, multiple sclerosis. CEAE has striking histological, electrophysiological and clinical analogies with multiple sclerosis and is a valuable animal model for the preclinical pharmacotherapeutical development of new putative therapeutic agents. In this paper, we describe a neurotrophic repair approach in Lewis rats suffering from CEAE. The neurotrophic peptide used is a degradation resistant adrenocorticotrophic hormone4-9 analog. The development of CEAE was examined using a combination of clinical, functional and electrophysiological parameters including somatosensory and motor evoked potentials. The latencies and amplitudes of the various evoked potentials can provide quantitative, objective data regarding the involvement of different nerve tracts in CEAE and the effectiveness of the neurotrophic peptide. Repeated subcutaneous injections of the neurotrophic peptide suppressed the development of CEAE-related clinical symptoms, markedly improved motor performance and reduced the reaction time upon thermal stimulation as compared to saline-treated CEAE animals during a 17 week follow-up study. Prolonged onset latencies of corticomotor evoked potentials and peak latencies of somatosensory evoked potentials due to the demyelination were normalized upon peptide treatment. In addition, peptide treatment substantially prevented total blocking of the corticomotor pathway in CEAE-animals and reduced the attenuation of sensory evoked potentials-related peak amplitudes as compared to saline-treated animals. The functional and electrophysiological improvements observed in CEAE-animals treated with the adrenocorticotrophic hormone4-9 analog, suggest that a neurotrophic repair approach could be of great value to promote the restoration of function in a disabling demyelinating disorder.
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Affiliation(s)
- H J Duckers
- Rudolf Magnus Institute for Neurosciences, Department of Medical Pharmacology, Medical Faculty, University of Utrecht, The Netherlands
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de Vries HE, Eppens EF, Prins M, Kuiper J, van Berkel TJ, de Boer AG, Breimer DD. Transport of a hydrophilic compound into the cerebrospinal fluid during experimental allergic encephalomyelitis and after lipopolysaccharide administration. Pharm Res 1995; 12:1932-6. [PMID: 8786968 DOI: 10.1023/a:1016291806357] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE The transport of the hydrophilic model compound sodium fluorescein into the cerebrospinal fluid (CSF) of rats was studied during experimental allergic encephalomyelitis (EAE), as a model for local central nervous system (CNS) inflammatory disease, and after a single injection of a pyrogenic dose of lipopolysaccharide (LPS), as a model for a general inflammation. METHODS Transport of sodium fluorescein was measured by means of serial CSF and plasma sampling. Transport of this hydrophilic model compound was studied in Lewis rats suffering from EAA and three hours after LPS administration in male Wistar rats. RESULTS During acute EAE, sodium fluorescein concentrations in the CSF increased twofold compared to control animals, whereas plasma kinetics were comparable within both groups. After i.v. LPS administration, however, plasma as well as CSF kinetic parameters of sodium fluorescein concentration were significantly changed from those seen in control animals. Transport of sodium fluorescein from plasma into the CSF was calculated as the ratio Area Under the Curve (AUC)CSF/AUCPLASMA. During acute EAE this ratio increased 2-fold compared to control animals, whereas after i.v. LPS administration it was not significantly different from the one obtained in control animals. CONCLUSIONS These results suggest an opening of the blood-brain barrier (BBB) during a cerebral inflammatory response, like acute EAE, but not after LPS administration.
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Affiliation(s)
- H E de Vries
- Leiden/Amsterdam Center for Drug Research, University of Leiden, Netherlands
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Stahl W, Dias JA, Turek G, Kaneda Y. Etiology of ovarian dysfunction in chronic murine toxoplasmosis. Parasitol Res 1995; 81:114-20. [PMID: 7731917 DOI: 10.1007/bf00931615] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ovarian dysfunction develops in Nya:NYLAR mice chronically infected with Toxoplasma gondii. To differentiate between primary ovarian failure and pituitary gonadotropin insufficiency, we (a) monitored ovarian responsiveness to pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) and (b) assessed endogenous pituitary gonadotropin capacity by the degree of ovarian compensatory hypertrophy (OCH) developing after unilateral ovariectomy (ULO). PMSG stimulated vigorous folliculogenesis and estrogen synthesis, but not ovulation. HCG given 3 days after PMSG induced "superovulation" within 16 h. These observations indicate the absence of the critical preovulatory surge of endogenous luteinizing hormone (LH) from the pituitary. In addition, ULO did not result in compensatory hypertrophy of the contralateral ovary, an indication of follicle-stimulating hormone (FSH) insufficiency. We hypothesize that cytokines released peripherally in response to the parasite reached the hypothalamus and initiated a sequence of events that inhibited the pulsatile release of gonadotropin-releasing hormone (GnRH), leading to the subsequent impairment of the pituitary-ovarian axis.
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Affiliation(s)
- W Stahl
- Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201, USA
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McMenamin P, Broekhuyse R, Forrester J. Ultrastructural pathology of experimental autoimmune uveitis: A review. Micron 1993. [DOI: 10.1016/0968-4328(93)90028-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Neu I, Mallinger J, Wildfeuer A, Mehlber L. Leukotrienes in the cerebrospinal fluid of multiple sclerosis patients. Acta Neurol Scand 1992; 86:586-7. [PMID: 1336293 DOI: 10.1111/j.1600-0404.1992.tb05491.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The concentration of the leukotrienes B4 (LTB4) and C4 (LTC4) was measured in the cerebrospinal fluid (CSF) of 38 multiple sclerosis (MS) patients and 51 with other neurological diseases. The LTB4 and LTC4 levels were significantly elevated in MS compared with the controls. The findings suggest that lipoxygenase products might play a pathogenetic role in the early, encephalitogenic phase of MS. The administration of lipoxygenase inhibitors or leukotriene antagonists might well open new perspectives for the treatment of MS.
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Affiliation(s)
- I Neu
- Sindelfingen Municipal Hospital, Germany
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Lightman S, Greenwood J. Effect of lymphocytic infiltration on the blood-retinal barrier in experimental autoimmune uveoretinitis. Clin Exp Immunol 1992; 88:473-7. [PMID: 1606733 PMCID: PMC1554517 DOI: 10.1111/j.1365-2249.1992.tb06474.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Using an experimental model of autoimmune uveoretinitis, we have examined the relationship of T cell infiltration in the retina to blood-retinal barrier (BRB) breakdown. Sensitive quantitative in vivo techniques were used to examine BRB permeability to sucrose, a low mol. wt non-transported solute. Electron microscopy was also used to localize extravasated horseradish peroxidase, a macromolecular visual tracer, from the retinal vasculature and to identify the route by which any leakage was occurring. No increase in BRB permeability was found prior to lymphocytic infiltration. By day 10 of the disease inflammatory cells could be seen within the structurally intact retina, which was shortly followed by an increase in the permeability of the BRB to sucrose. Only later in the disease process, when damage to the photoreceptor layer became apparent, did extravasation of the macromolecule HRP occur. At no stage of the disease process was there any detectable damage to inter-endothelial tight junctions. The size-dependancy of tracer extravasation in the initial stages of the disease is indicative of a paracellular route being responsible for the increase in BRB permeability. In later stages of the disease some evidence of horseradish peroxidase filled 'vesicle-like' profiles was observed. We suggest that the devastating complication of BRB breakdown in ocular inflammation is a direct consequence of lymphocytic infiltration.
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Affiliation(s)
- S Lightman
- Department of Clinical Science, Institute of Ophthalmology, London, UK
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Greenwood J. The blood-retinal barrier in experimental autoimmune uveoretinitis (EAU): a review. Curr Eye Res 1992; 11 Suppl:25-32. [PMID: 1424749 DOI: 10.3109/02713689208999508] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The blood-retinal barrier (BRB) is believed to play an important part in the pathogenesis of experimental autoimmune uveoretinitis (EAU). Central to the disease process is the recruitment of inflammatory cells from the circulation, a mechanism that is controlled in part by the BRB. As the disease progresses the BRB becomes disrupted first to small and then to large molecular weight tracers. In these two respects EAU shares many similarities with experimental autoimmune encephalomyelitis (EAE) in which there is dysfunction of the blood-brain barrier (BBB). In EAU, however, the differential roles played by the two barrier sites that comprise the BRB are not clear although some evidence would suggest that it is the retinal endothelium that is initially involved. BRB breakdown in EAU has been found to occur concomitantly with lymphocyte infiltration by mechanisms that remain to be elucidated.
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Affiliation(s)
- J Greenwood
- Department of Clinical Science, Institute of Ophthalmology, London, UK
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Iannotti F. Functional imaging of blood brain barrier permeability by single photon emission computerised tomography and positron emission tomography. Adv Tech Stand Neurosurg 1992; 19:103-19. [PMID: 1418118 DOI: 10.1007/978-3-7091-6672-7_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- F Iannotti
- Istituto di Neurochirurgia, I Facoltà Medica, Università degli Studi di Napoli, Italy
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12
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Abstract
The functional status of the blood-brain barrier (BBB) must be taken into account when designing and interpreting brain imaging techniques. The integrity of the BBB is affected in many diseases of the brain, with the potential involvement of a number of different but poorly understood cellular mechanisms. Factors known to disrupt the BBB experimentally include arachidonic acid and the eicosanoids, bradykinin, histamine and free radicals. These active compounds, released in pathological tissue, may alter cytosolic calcium levels and induce second messenger systems leading to an alteration in BBB permeability. Extravasation of plasma proteins may occur via disrupted tight junctions, stimulation of fluid-phase vesicular transport or the formation of transcellular pores or channels.
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Affiliation(s)
- J Greenwood
- Department of Clinical Science, Institute of Ophthalmology, London, UK
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13
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Prosiegel M, Neu I, Vogl S, Hoffmann G, Wildfeuer A, Ruhenstroth-Bauer G. Suppression of experimental autoimmune encephalomyelitis by sulfasalazine. Acta Neurol Scand 1990; 81:237-8. [PMID: 1972308 DOI: 10.1111/j.1600-0404.1990.tb00973.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
It has recently been suggested that the sulfidopeptide leukotriene C4 (LTC4), a 5-lipoxygenase product of the arachidonic acid metabolism and one of the most potent mediators of vascular permeability, might be involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). Subsequently, 20 guinea pigs with EAE were treated with sulfasalazine, a substance with a proved leukotriene inhibiting effect, which has previously been described as exerting beneficial effects in patients with inflammatory bowel disease and rheumatoid arthritis. The sulfasalazine-treated guinea pigs showed a significantly better clinical outcome, as well as a significantly lower histological inflammation score compared with 19 controls.
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Affiliation(s)
- M Prosiegel
- Department of Neurology, Fachklinik Enzensberg, Hopfen am See, West Germany
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Konkol RJ, Wesselmann U, Karpus WJ, Leo GL, Killen JA, Roerig DL. Suppression of clinical weakness in experimental autoimmune encephalomyelitis associated with weight changes, and post-decapitation convulsions after intracisternal-ventricular administration of 6-hydroxydopamine. J Neuroimmunol 1990; 26:25-34. [PMID: 1688441 DOI: 10.1016/0165-5728(90)90116-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Selective depletion of central nervous system norepinephrine (NE) by the neurotoxin 6-hydroxydopamine (6-OHDA) in rats subsequently inoculated with myelin basic protein (MBP) and complete Freund's adjuvant (CFA) produced experimental autoimmune encephalomyelitis (EAE) without the usual expected degree of weakness. The preservation of strength occurred in spite of continued weight loss. Post-decapitation myoclonic convulsive kick latency and kick number, which are known to depend on spinal cord NE, agreed well with the degree of weakness through the clinical disease course. The only difference between EAE groups was that the stronger 6-OHDA pretreated EAE animals did not have an elevated pons-medulla NE compared to saline intracisternal-ventricular (i.c.v.) pretreated controls. We conclude that 6-OHDA can influence the clinical course of weakness by interfering with central noradrenergic activity independent of other features associated with disease in EAE. This effect of 6-OHDA may be exerted through alteration of the blood-spinal cord barrier function and/or central nervous system blood flow.
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Affiliation(s)
- R J Konkol
- Department of Neurology, Medical College of Wisconsin, Milwaukee
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