1
|
Abstract
Human herpesvirus 6A (HHV-6A) and human herpesvirus 6B (HHV-6B), collectively termed HHV-6A/B, are neurotropic viruses that permanently infect most humans from an early age. Although most people infected with these viruses appear to suffer no ill effects, the viruses are a well-established cause of encephalitis in immunocompromised patients. In this review, we summarize the evidence that the viruses may also be one trigger for febrile seizures (including febrile status epilepticus) in immunocompetent infants and children, mesial temporal lobe epilepsy, multiple sclerosis (MS), and, possibly, Alzheimer's disease. We propose criteria for linking ubiquitous infectious agents capable of producing lifelong infection to any neurologic disease, and then we examine to what extent these criteria have been met for these viruses and these diseases.
Collapse
Affiliation(s)
- Anthony L Komaroff
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Philip E Pellett
- Department of Microbiology and Immunology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Steven Jacobson
- Virology/Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
2
|
Bell LA, Wallis GJ, Wilcox KS. Reactivity and increased proliferation of NG2 cells following central nervous system infection with Theiler's murine encephalomyelitis virus. J Neuroinflammation 2020; 17:369. [PMID: 33272299 PMCID: PMC7713670 DOI: 10.1186/s12974-020-02043-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/24/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Neuron-glial antigen 2 (NG2) cells are a glial cell type tiled throughout the gray and white matter of the central nervous system (CNS). NG2 cells are known for their ability to differentiate into oligodendrocytes and are commonly referred to as oligodendrocyte precursor cells. However, recent investigations have begun to identify additional functions of NG2 cells in CNS health and pathology. NG2 cells form physical and functional connections with neurons and other glial cell types throughout the CNS, allowing them to monitor and respond to the neural environment. Growing evidence indicates that NG2 cells become reactive under pathological conditions, though their specific roles are only beginning to be elucidated. While reactive microglia and astrocytes are well-established contributors to neuroinflammation and the development of epilepsy following CNS infection, the dynamics of NG2 cells remain unclear. Therefore, we investigated NG2 cell reactivity in a viral-induced mouse model of temporal lobe epilepsy. METHODS C57BL6/J mice were injected intracortically with Theiler's murine encephalomyelitis virus (TMEV) or PBS. Mice were graded twice daily for seizures between 3 and 7 days post-injection (dpi). At 4 and 14 dpi, brains were fixed and stained for NG2, the microglia/macrophage marker IBA1, and the proliferation marker Ki-67. Confocal z stacks were acquired in both the hippocampus and the overlying cortex. Total field areas stained by each cell marker and total field area of colocalized pixels between NG2 and Ki67 were compared between groups. RESULTS Both NG2 cells and microglia/macrophages displayed increased immunoreactivity and reactive morphologies in the hippocampus of TMEV-injected mice. While increased immunoreactivity for IBA1 was also present in the cortex, there was no significant change in NG2 immunoreactivity in the cortex following TMEV infection. Colocalization analysis for NG2 and Ki-67 revealed a significant increase in overlap between NG2 and Ki-67 in the hippocampus of TMEV-injected mice at both time points, but no significant differences in cortex. CONCLUSIONS NG2 cells acquire a reactive phenotype and proliferate in response to TMEV infection. These results suggest that NG2 cells alter their function in response to viral encephalopathy, making them potential targets to prevent the development of epilepsy following viral infection.
Collapse
Affiliation(s)
- Laura A Bell
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, 84112, USA
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, 84112, USA
| | - Glenna J Wallis
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Karen S Wilcox
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, 84112, USA.
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, 84112, USA.
| |
Collapse
|
3
|
Barker-Haliski ML, Heck TD, Dahle EJ, Vanegas F, Pruess TH, Wilcox KS, White HS. Acute treatment with minocycline, but not valproic acid, improves long-term behavioral outcomes in the Theiler's virus model of temporal lobe epilepsy. Epilepsia 2016; 57:1958-1967. [PMID: 27739576 PMCID: PMC5154893 DOI: 10.1111/epi.13577] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2016] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Infection with Theiler's murine encephalomyelitis virus (TMEV) in C57Bl/6J mice induces acute seizures and development of spontaneous recurrent seizures and behavioral comorbidities weeks later. The present studies sought to determine whether acute therapeutic intervention with an anti-inflammatory-based approach could prevent or modify development of TMEV-induced long-term behavioral comorbidities. Valproic acid (VPA), in addition to its prototypical anticonvulsant properties, inhibits histone deacetylase (HDAC) activity, which may alter expression of the inflammasome. Minocycline (MIN) has previously demonstrated an antiseizure effect in the TMEV model via direct anti-inflammatory mechanisms, but the long-term effect of MIN treatment on the development of chronic behavioral comorbidities is unknown. METHODS Mice infected with TMEV were acutely administered MIN (50 mg/kg, b.i.d. and q.d.) or VPA (100 mg/kg, q.d.) during the 7-day viral infection period. Animals were evaluated for acute seizure severity and subsequent development of chronic behavioral comorbidities and seizure threshold. RESULTS Administration of VPA reduced the proportion of mice with seizures, delayed onset of symptomatic seizures, and reduced seizure burden during the acute infection. This was in contrast to the effects of administration of once-daily MIN, which did not affect the proportion of mice with seizures or delay onset of acute symptomatic seizures. However, VPA-treated mice were no different from vehicle (VEH)-treated mice in long-term behavioral outcomes, including open field activity and seizure threshold. Once-daily MIN treatment, despite no effect on the maximum observed Racine stage seizure severity, was associated with improved long-term behavioral outcomes and normalized seizure threshold. SIGNIFICANCE Acute seizure control alone is insufficient to modify chronic disease comorbidities in the TMEV model. This work further supports the role of an inflammatory response in the development of chronic behavioral comorbidities and further highlights the utility of this platform for the development of mechanistically novel pharmacotherapies for epilepsy.
Collapse
Affiliation(s)
- Melissa L. Barker-Haliski
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
- Department of Pharmacy, School of Pharmacy, University of Washington, Box 357630, H375 Health Sciences Building, Seattle, WA 98195-7630
| | - Taylor D. Heck
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
| | - E. Jill Dahle
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
| | - Fabiola Vanegas
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
| | - Timothy H. Pruess
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
| | - Karen S. Wilcox
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
| | - H. Steve White
- Anticonvulsant Drug Development Program, Dept. of Pharmacology & Toxicology, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, 801-581-6733
- Department of Pharmacy, School of Pharmacy, University of Washington, Box 357630, H375 Health Sciences Building, Seattle, WA 98195-7630
| |
Collapse
|
4
|
Karatas H, Gurer G, Pinar A, Soylemezoglu F, Tezel GG, Hascelik G, Akalan N, Tuncer S, Ciger A, Saygi S. Investigation of HSV-1, HSV-2, CMV, HHV-6 and HHV-8 DNA by real-time PCR in surgical resection materials of epilepsy patients with mesial temporal lobe sclerosis. J Neurol Sci 2008; 264:151-6. [PMID: 17804017 DOI: 10.1016/j.jns.2007.08.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2006] [Revised: 08/08/2007] [Accepted: 08/13/2007] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The objective of this study is to investigate the presence of viral DNAs of HSV-1, HSV-2, HHV-6, HHV-8, and CMV in hippocampus of the patients with mesial temporal lobe epilepsy (MTLE) syndrome. METHODS Pathological specimens were obtained from 33 patients with MTLE undergone temporal lobectomy with amygdalo-hippocampectomy due to intractable seizures. Autopsy materials from the hippocampus of 7 patients without neurological disease were used as controls. The data was also correlated with the clinical history of patients including febrile convulsions, age, and history of CNS infections. Real-time polymerase chain reaction method was performed for detection of DNAs of these viruses. RESULTS HHV-6, HSV-1 and HHV-8 were detected in the hippocampus of 3, 2 and 1 patients with MTLE respectively. None of the hippocampus of patients with MTLE was positive for DNA of HSV-2 and/or CMV. Three patients with positive HHV-6 DNAs had febrile convulsions and family history for epilepsy. None of our control specimens showed PCR positivity to any of the 5 tested viruses. CONCLUSIONS Our study is the first to report the presence of HHV-8 viral genome in the brain tissue of patient with MTLE. Viral DNAs were detected in a total of 18% of the patients in this study; we can conclude that activity of the latent virus in patients with hippocampal sclerosis should be more extensively studied to establish its role in active infection.
Collapse
MESH Headings
- Adolescent
- Adult
- Autopsy
- Cytomegalovirus/genetics
- DNA, Viral/analysis
- Encephalitis, Herpes Simplex/complications
- Encephalitis, Herpes Simplex/diagnosis
- Encephalitis, Herpes Simplex/genetics
- Epilepsy, Temporal Lobe/pathology
- Epilepsy, Temporal Lobe/physiopathology
- Epilepsy, Temporal Lobe/virology
- Female
- Herpes Simplex/complications
- Herpesviridae Infections/complications
- Herpesviridae Infections/diagnosis
- Herpesviridae Infections/genetics
- Herpesvirus 1, Human/genetics
- Herpesvirus 2, Human/genetics
- Herpesvirus 6, Human/genetics
- Herpesvirus 8, Human/genetics
- Hippocampus/pathology
- Hippocampus/physiopathology
- Hippocampus/virology
- Humans
- Male
- Reverse Transcriptase Polymerase Chain Reaction
- Virus Latency/genetics
Collapse
Affiliation(s)
- Hulya Karatas
- Hacettepe University, Faculty of Medicine, Department of Neurology, Sihhiye, Ankara, 06100, Turkey.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Seeley WW, Marty FM, Holmes TM, Upchurch K, Soiffer RJ, Antin JH, Baden LR, Bromfield EB. Post-transplant acute limbic encephalitis: clinical features and relationship to HHV6. Neurology 2007; 69:156-65. [PMID: 17620548 DOI: 10.1212/01.wnl.0000265591.10200.d7] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Acute limbic encephalitis has been reported in the setting of treatment-related immunosuppression and attributed to human herpesvirus-6 (HHV6) infection. Clinical and laboratory features of the syndrome, however, have not been well characterized. METHODS We describe the clinical, EEG, MRI, and laboratory features of nine patients with acute limbic encephalitis after allogeneic hematopoietic stem cell transplantation (HSCT). To explore the relationship between HHV6 and this syndrome, we reviewed available CSF HHV6 PCR results from all HSCT patients seen at our center from March 17, 2003, through March 31, 2005. RESULTS Patients displayed a consistent and distinctive clinical syndrome featuring anterograde amnesia, the syndrome of inappropriate antidiuretic hormone secretion, mild CSF pleocytosis, and temporal EEG abnormalities, often reflecting clinical or subclinical seizures. MRI showed hyperintensities within the uncus, amygdala, entorhinal area, and hippocampus on T2, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) sequences. CSF PCR assays for HHV6 were positive in six of nine patients on initial lumbar puncture. All patients were treated with foscarnet or ganciclovir. Cognitive recovery varied among long-term survivors. The one brain autopsy showed limbic gliosis and profound neuronal loss in amygdala and hippocampus. Among 27 HSCT patients with CSF tested for HHV6 over a 2-year period, positive results occurred only in patients with clinical limbic encephalitis. CONCLUSIONS Patients undergoing allogeneic hematopoietic stem cell transplantation are at risk for post-transplant acute limbic encephalitis (PALE), a distinct neurologic syndrome. Treatment considerations should include aggressive seizure control and, possibly, antiviral therapy. PALE can be associated with the CSF presence of human herpesvirus-6, but the pathogenic role of the virus requires further exploration.
Collapse
MESH Headings
- Adult
- Amnesia, Anterograde/immunology
- Amnesia, Anterograde/physiopathology
- Amnesia, Anterograde/virology
- Amygdala/pathology
- Amygdala/physiopathology
- Antiviral Agents/therapeutic use
- Diabetes Insipidus/immunology
- Diabetes Insipidus/physiopathology
- Diabetes Insipidus/virology
- Encephalitis, Herpes Simplex/immunology
- Encephalitis, Herpes Simplex/physiopathology
- Encephalitis, Herpes Simplex/virology
- Epilepsy, Temporal Lobe/immunology
- Epilepsy, Temporal Lobe/physiopathology
- Epilepsy, Temporal Lobe/virology
- Hematopoietic Stem Cell Transplantation/adverse effects
- Herpesvirus 6, Human/immunology
- Hippocampus/pathology
- Hippocampus/physiopathology
- Humans
- Limbic Encephalitis/immunology
- Limbic Encephalitis/physiopathology
- Limbic Encephalitis/virology
- Magnetic Resonance Imaging
- Male
- Middle Aged
- Postoperative Complications/immunology
- Postoperative Complications/physiopathology
- Postoperative Complications/virology
- Treatment Outcome
Collapse
Affiliation(s)
- W W Seeley
- Department of Neurology, Brigham & Women's Hospital, Boston, MA, USA.
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Fotheringham J, Donati D, Akhyani N, Fogdell-Hahn A, Vortmeyer A, Heiss JD, Williams E, Weinstein S, Bruce DA, Gaillard WD, Sato S, Theodore WH, Jacobson S. Association of human herpesvirus-6B with mesial temporal lobe epilepsy. PLoS Med 2007; 4:e180. [PMID: 17535102 PMCID: PMC1880851 DOI: 10.1371/journal.pmed.0040180] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Accepted: 03/29/2007] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Human herpesvirus-6 (HHV-6) is a beta-herpesvirus with 90% seroprevalence that infects and establishes latency in the central nervous system. Two HHV-6 variants are known: HHV-6A and HHV-6B. Active infection or reactivation of HHV-6 in the brain is associated with neurological disorders, including epilepsy, encephalitis, and multiple sclerosis. In a preliminary study, we found HHV-6B DNA in resected brain tissue from patients with mesial temporal lobe epilepsy (MTLE) and have localized viral antigen to glial fibrillary acidic protein (GFAP)-positive glia in the same brain sections. We sought, first, to determine the extent of HHV-6 infection in brain material resected from MTLE and non-MTLE patients; and second, to establish in vitro primary astrocyte cultures from freshly resected brain material and determine expression of glutamate transporters. METHODS AND FINDINGS HHV-6B infection in astrocytes and brain specimens was investigated in resected brain material from MTLE and non-MTLE patients using PCR and immunofluorescence. HHV-6B viral DNA was detected by TaqMan PCR in brain resections from 11 of 16 (69%) additional patients with MTLE and from zero of seven (0%) additional patients without MTLE. All brain regions that tested positive by HHV-6B variant-specific TaqMan PCR were positive for viral DNA by nested PCR. Primary astrocytes were isolated and cultured from seven epilepsy brain resections and astrocyte purity was defined by GFAP reactivity. HHV-6 gp116/54/64 antigen was detected in primary cultured GFAP-positive astrocytes from resected tissue that was HHV-6 DNA positive-the first demonstration of an ex vivo HHV-6-infected astrocyte culture isolated from HHV-6-positive brain material. Previous work has shown that MTLE is related to glutamate transporter dysfunction. We infected astrocyte cultures in vitro with HHV-6 and found a marked decrease in glutamate transporter EAAT-2 expression. CONCLUSIONS Overall, we have now detected HHV-6B in 15 of 24 patients with mesial temporal sclerosis/MTLE, in contrast to zero of 14 with other syndromes. Our results suggest a potential etiology and pathogenic mechanism for MTLE.
Collapse
Affiliation(s)
- Julie Fotheringham
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Donatella Donati
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
- Struttura Complessa di Microbiologia e Virologia, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Nahid Akhyani
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anna Fogdell-Hahn
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Clinical Neuroscience, Division of Neurology, Karolinska Institutet, Stockholm, Sweden
| | - Alexander Vortmeyer
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John D Heiss
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Elizabeth Williams
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Steven Weinstein
- Children's National Medical Center, Washington, District of Columbia, United States of America
| | - Derek A Bruce
- Children's National Medical Center, Washington, District of Columbia, United States of America
| | - William D Gaillard
- Children's National Medical Center, Washington, District of Columbia, United States of America
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Maryland, United States of America
| | - Susumu Sato
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Maryland, United States of America
| | - William H Theodore
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Maryland, United States of America
| | - Steven Jacobson
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
7
|
Yamashita N, Morishima T. HHV-6 and seizures. Herpes 2005; 12:46-9. [PMID: 16209861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Accepted: 07/18/2005] [Indexed: 05/04/2023]
Abstract
Human herpes virus-6 (HHV-6) is a ubiquitous virus, but one that can induce various neurological diseases. Recently, several seizures have been reported as new HHV-6-associated diseases based on virological analysis. Neonates who are perinatally infected with HHV-6 can develop afebrile seizures, which are considered to be exanthem subitum (ES) in the neonatal period. Infants with ES also tend to develop atypical febrile seizures. After primary infection, HHV-6 commonly establishes latency in the central nervous system (CNS) and sometimes reactivates in the hippocampus, causing limbic encephalitis and temporal lobe epilepsy. These HHV-6-associated CNS diseases due to virus reactivation can occur in both immunocompromised and immunocompetent hosts. This article summarizes HHV-6-associated seizures during childhood.
Collapse
Affiliation(s)
- Nobuko Yamashita
- Department of Pediatrics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | | |
Collapse
|
8
|
Eeg-Olofsson O, Bergström T, Andermann F, Andermann E, Olivier A, Rydenhag B. Herpesviral DNA in brain tissue from patients with temporal lobe epilepsy. Acta Neurol Scand 2004; 109:169-74. [PMID: 14763952 DOI: 10.1046/j.1600-0404.2003.00238.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Presence of DNA from six herpesviruses were examined in brain tissue from patients operated for temporal lobe epilepsy. MATERIAL AND METHODS A total of 19 Canadian patients (I) with a median age of 22 years, 17 Swedish patients (II) with a median age of 14 years and a reference group comprising 12 individuals were studied. Presence of herpesviral DNA was detected by nested polymerase chain reaction. RESULTS Of three children with Rasmussen's encephalitis, Cytomegalovirus (CMV) DNA was found in two, and human herpesvirus type 6 DNA in two. In six children with ganglioglioma, Epstein-Barr virus (EBV) was detected in four. CMV DNA was found significantly more in group I compared with II, while the reverse occurred with EBV DNA. Malformations of cortical development were found significantly more in group II compared with I. CONCLUSION Detection of DNA from some herpesviruses in epileptic brain tissue may possibly be associated with distinct clinical conditions, but factors such as age and malformations of cortical development should also be considered.
Collapse
Affiliation(s)
- O Eeg-Olofsson
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. orvar@
| | | | | | | | | | | |
Collapse
|
9
|
Donati D, Akhyani N, Fogdell-Hahn A, Cermelli C, Cassiani-Ingoni R, Vortmeyer A, Heiss JD, Cogen P, Gaillard WD, Sato S, Theodore WH, Jacobson S. Detection of human herpesvirus-6 in mesial temporal lobe epilepsy surgical brain resections. Neurology 2004; 61:1405-11. [PMID: 14638964 PMCID: PMC4294224 DOI: 10.1212/01.wnl.0000094357.10782.f9] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Human herpesvirus-6 (HHV-6), a ubiquitous beta-herpesvirus, is the causative agent of roseola infantum and has been associated with a number of neurologic disorders including seizures, encephalitis/meningitis, and multiple sclerosis. Although the role of HHV-6 in human CNS disease remains to be fully defined, a number of studies have suggested that the CNS can be a site for persistent HHV-6 infection. OBJECTIVE To characterize the extent and distribution of HHV-6 in human glial cells from surgical brain resections of patients with mesial temporal lobe epilepsy (MTLE). METHOD Brain samples from eight patients with MTLE and seven patients with neocortical epilepsy (NE) undergoing surgical resection were quantitatively analyzed for the presence of HHV-6 DNA using a virus-specific real-time PCR assay. HHV-6 expression was also characterized by western blot analysis and in situ immunohistochemistry (IHC). In addition, HHV-6-reactive cells were analyzed for expression of glial fibrillary acidic protein (GFAP) by double immunofluorescence. RESULTS DNA obtained from four of eight patients with MTLE had significantly elevated levels of HHV-6 as quantified by real-time PCR. HHV-6 was not amplified in any of the seven patients with NE undergoing surgery. The highest levels of HHV-6 were demonstrated in hippocampal sections (up to 23,079 copies/10(6) cells) and subtyped as HHV-6B. Expression of HHV-6 was confirmed by western blot analysis and IHC. HHV-6 was co-localized to GFAP-positive cells that morphologically appeared to be astrocytes. CONCLUSIONS HHV-6B is present in brain specimens from a subset of patients with MTLE and localized to astrocytes in the absence of inflammation. The amplification of HHV-6 from hippocampal and temporal lobe astrocytes of MTLE warrants further investigation into the possible role of HHV-6 in the development of MTLE.
Collapse
Affiliation(s)
- D Donati
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Wu HM, Huang CC, Chen SH, Liang YC, Tsai JJ, Hsieh CL, Hsu KS. Herpes simplex virus type 1 inoculation enhances hippocampal excitability and seizure susceptibility in mice. Eur J Neurosci 2003; 18:3294-304. [PMID: 14686902 DOI: 10.1111/j.1460-9568.2003.03075.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herpes simplex virus type 1 (HSV-1) is the major pathogen related to epilepsy. However, little is known about the pathogenesis of HSV-1-associated epilepsy. Here, we report that corneal inoculation of mice with HSV-1 induces acute spontaneous behavioural and electrophysiological seizures and chronically increases hippocampal excitability and seizure susceptibility. In slices from infected mice, the surviving hippocampal CA3 pyramidal neurons exhibited a more depolarizing resting membrane potential concomitant with an increase in membrane input resistance. They also had a lower threshold for generating synchronized bursts and a decrease in the amplitude of afterhyperpolarization (AHP) than did controls. These results suggest that a direct change in the excitability of the hippocampal CA3 neuronal network could play an important role in facilitating the development of acute seizures and subsequent epilepsy.
Collapse
Affiliation(s)
- Hung-Ming Wu
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | | | | | | | | | | | | |
Collapse
|
11
|
Abstract
Mechanisms by which perinatal viral infections can disrupt hippocampal development and cause selective neuronal death may have implications for temporal lobe epilepsy and schizophrenia. Despite abnormalities of inhibitory interneurons in these diseases, the causal relationships between such neurotransmitter changes and viral infections remain unclear. This relationship was examined in a model in which rats, infected with lymphocytic choriomeningitis virus (LCMV) as neonates, manifest a gradual loss of hippocampal dentate granule cells and neuronal hyperexcitability. The current data demonstrate that GABAergic interneurons are dual immunostained for LCMV antigens prior to the loss of dentate granule cells, supporting the hypothesis that LCMV may disrupt developing inhibitory circuits causing unbalanced excitatory neurotransmission and the eventual death of dentate granule cells due to excitotoxicity.
Collapse
Affiliation(s)
- B D Pearce
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | | | | |
Collapse
|