1
|
Maltsev D, Solonko I, Sydorenko O. The assessment of microbial infection in children with autism spectrum disorders and genetic folate cycle deficiency. BMC Pediatr 2024; 24:200. [PMID: 38515059 PMCID: PMC10956213 DOI: 10.1186/s12887-024-04687-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/02/2024] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND The results of disparate clinical studies indicate abnormally frequent cases of certain microorganisms in children with autism spectrum disorders (ASD). However, these data require clarification and systematization. The study aims to study the structure of the microbial profile in children with ASD and genetic folate cycle deficiency (GFCD) and consider differences in diagnostic approaches for identifying microorganisms of different types. METHODS The study analyzed medical data from 240 children (187 boys and 63 girls) with GFCD aged 2 to 9 years. The children had clinical manifestations of ASD (the study group, SG). The control group (CG) included 53 clinically healthy children (37 boys and 16 girls) of the same age but without GFCD. Both groups of children were tested on active herpetic infections (HSV-1/2, VZV, EBV, CMV, HHV-6, HHV-7, HHV-8), ТТV, Streptococcus pyogenes, Candida albicans, Borrelia burgdorferi, Mycoplasma pneumoniae, Chlamydia pneumoniae, Yersinia enterocolitica, Toxoplasma gondii, congenital CMV neuroinfection and postnatal HSV-1/2 encephalitis. The testing used diagnostic methods specified in PubMed-indexed studies. RESULTS In the SG, TTV was found in 196 children (82%), HHV-7 - in 172 (72%), HHV-6 - in 162 (68%), EBV - in 153 (64%), Streptococcus pyogenes - in 127 (53%), Candida albicans - in 116 (48%), Borrelia - in 107 (45%), Mycoplasma pneumoniae - in 94 (39%), Chlamydia pneumoniae - in 85 (35%), Yersinia entеrocolitica - in 71 (30%), Toxoplasma gondii - in 54 (23%), congenital CMV neuroinfection - in 26 (11%), and postnatal HSV-1/2 encephalitis - in 11 children (5% of cases) (p < p0.05; Z < Z0.05). In the SG, there was a higher microbial load in older children (p < p0.05; Z < Z0.05). No gender differences were found. CONCLUSIONS The study described and characterized a specific abnormal microbial spectrum with a predominance of viral opportunistic agents in children with ASD associated with GFCD.
Collapse
Affiliation(s)
- Dmitry Maltsev
- Laboratory of Immunology and Molecular Biology, Research Institute of Experimental and Clinical Medicine, O'Bogomolets National Medical University, Kyiv, Ukraine.
| | - Iryna Solonko
- Laboratory of Immunology and Molecular Biology, Research Institute of Experimental and Clinical Medicine, O'Bogomolets National Medical University, Kyiv, Ukraine
| | - Olena Sydorenko
- Laboratory of Immunology and Molecular Biology, Research Institute of Experimental and Clinical Medicine, O'Bogomolets National Medical University, Kyiv, Ukraine
| |
Collapse
|
2
|
Goh M, Joy C, Gillespie AN, Soh QR, He F, Sung V. Asymptomatic viruses detectable in saliva in the first year of life: a narrative review. Pediatr Res 2024; 95:508-531. [PMID: 38135726 DOI: 10.1038/s41390-023-02952-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/15/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023]
Abstract
Viral infections are common in children. Many can be asymptomatic or have delayed health consequences. In view of increasing availability of point-of-care viral detection technologies, with possible application in newborn screening, this review aimed to (1) identify potentially asymptomatic viruses detectable in infants under one year old, via saliva/nasopharyngeal swab, and (2) describe associations between viruses and long-term health conditions. We systematically searched Embase(Ovid), Medline(Ovid) and PubMed, then further searched the literature in a tiered approach. From the 143 articles included, 28 potentially asymptomatic viruses were identified. Our second search revealed associations with a range of delayed health conditions, with most related to the severity of initial symptoms. Many respiratory viruses were linked with development of recurrent wheeze or asthma. Of note, some potentially asymptomatic viruses are linked with later non-communicable diseases: adenovirus serotype 36 and obesity, Enterovirus-A71 associated Hand, Foot, Mouth Disease and Attention-Deficit Hyperactivity Disorder, Ebstein Barr Virus (EBV) and malignancy, EBV and multiple sclerosis, HHV-6 and epilepsy, HBoV-1 and lung fibrosis and Norovirus and functional gastrointestinal disorders. Our review identified many potentially asymptomatic viruses, detectable in early life with potential delayed health consequences, that could be important to screen for in the future using rapid point-of-care viral detection methods. IMPACT: Novel point-of-care viral detection technologies enable rapid detection of viruses, both old and emerging. In view of increasing capability to screen for viruses, this is the first review to explore which potentially asymptomatic viruses, that are detectable using saliva and/or nasopharyngeal swabs in infants less than one year of age, are associated with delayed adverse health conditions. Further research into detecting such viruses in early life and their delayed health outcomes may pave new ways to prevent non-communicable diseases in the future.
Collapse
Affiliation(s)
- Melody Goh
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
- Prevention Innovation, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - Charissa Joy
- Prevention Innovation, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Monash Children's Hospital Clayton, Clayton, VIC, Australia
| | - Alanna N Gillespie
- Prevention Innovation, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Centre for Community Child Health, The Royal Children's Hospital, Parkville, VIC, Australia
| | - Qi Rui Soh
- Prevention Innovation, Murdoch Children's Research Institute, Parkville, VIC, Australia
- The University of Melbourne, Faculty of Medicine Dentistry and Health Sciences Melbourne, Melbourne, VIC, Australia
| | - Fan He
- Prevention Innovation, Murdoch Children's Research Institute, Parkville, VIC, Australia
- John Richards Centre for Rural Ageing Research, La Trobe University, Wodonga, VIC, Australia
| | - Valerie Sung
- Prevention Innovation, Murdoch Children's Research Institute, Parkville, VIC, Australia.
- Monash Children's Hospital Clayton, Clayton, VIC, Australia.
- Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia.
| |
Collapse
|
3
|
de Fàbregues O, Sellés M, Ramos-Vicente D, Roch G, Vila M, Bové J. Relevance of tissue-resident memory CD8 T cells in the onset of Parkinson's disease and examination of its possible etiologies: infectious or autoimmune? Neurobiol Dis 2023; 187:106308. [PMID: 37741513 DOI: 10.1016/j.nbd.2023.106308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/05/2023] [Accepted: 09/20/2023] [Indexed: 09/25/2023] Open
Abstract
Tissue-resident memory CD8 T cells are responsible for local immune surveillance in different tissues, including the brain. They constitute the first line of defense against pathogens and cancer cells and play a role in autoimmunity. A recently published study demonstrated that CD8 T cells with markers of residency containing distinct granzymes and interferon-γ infiltrate the parenchyma of the substantia nigra and contact dopaminergic neurons in an early premotor stage of Parkinson's disease. This infiltration precedes α-synuclein aggregation and neuronal loss in the substantia nigra, suggesting a relevant role for CD8 T cells in the onset of the disease. To date, the nature of the antigen that initiates the adaptive immune response remains unknown. This review will discuss the role of tissue-resident memory CD8 T cells in brain immune homeostasis and in the onset of Parkinson's disease and other neurological diseases. We also discuss how aging and genetic factors can affect the CD8 T cell immune response and how animal models can be misleading when studying human-related immune response. Finally, we speculate about a possible infectious or autoimmune origin of Parkinson's disease.
Collapse
Affiliation(s)
- Oriol de Fàbregues
- Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute, Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona, Catalonia, Spain; Movement Disorders Unit, Neurology Department, Vall d'Hebron University Hospital
| | - Maria Sellés
- Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute, Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona, Catalonia, Spain
| | - David Ramos-Vicente
- Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute, Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona, Catalonia, Spain
| | - Gerard Roch
- Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute, Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona, Catalonia, Spain
| | - Miquel Vila
- Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute, Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona, Catalonia, Spain; Department of Biochemistry and Molecular Biology, Autonomous University of Barcelona, Barcelona, Catalonia, Spain; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA; Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Catalonia, Spain
| | - Jordi Bové
- Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute, Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona, Catalonia, Spain.
| |
Collapse
|
4
|
Wang JQ, Yang HY, Shao X, Jiang XY, Li JM. Latent, Early or Late Human Herpes Virus-6B Expression in Adult Mesial Temporal Lobe Epilepsy: Association of Virus Life Cycle with Inflammatory Cytokines in Brain Tissue and Cerebral Spinal Fluid. Neuroscience 2022; 504:21-32. [PMID: 36067950 DOI: 10.1016/j.neuroscience.2022.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/08/2022] [Accepted: 08/25/2022] [Indexed: 10/31/2022]
Abstract
BACKGROUND Human herpes virus-6B (HHV-6B) was suggested as an important etiologic factor of mesial temporal lobe epilepsy, while the mechanism is still unknown. Here, we aimed to analyze antigens representing latent, early and late HHV-6B infection and the association with inflammatory cytokines in brain tissue and cerebral spinal fluid (CSF) from MTLE patients with HHV-6B-positivity. METHODS Nested polymerase chain reaction (nPCR), real-time PCR, immunohistochemistry (ICH) and suspension bead array for cytokines were performed. RESULTS Nested polymerase chain reaction (nPCR) in brain tissue revealed HHV-6B DNA in 19 of 49 MTLE patients (39%) and 1 of 19 controls (5%) (P < 0.001), but not in CSF. ICH showed HHV-6B early antigen (P41) positivity in 3 patients (6%), late antigen (gp116/54/64) positivity in 5 patients (10%), latent antigen (U94) positivity in 8 patients (16%), and multiple antigen (early and late or/and latent) positivity in 9 patients (18%). None of these HHV-6B related proteins were found positive in control brain tissue. PCR revealed significant up-regulation of IL-1a, IL-2 and IL-7 mRNA levels in the brain tissue from MTLE patients expressing early antigens compared to those expressing late, latent, multiple antigens, negative antigens and the controls. Suspension bead array of the CSF confirmed significant up-regulation of IL-1a and IL-7 protein expression from MTLE patients expressing early antigens compared to the other groups. CONCLUSIONS Our finding suggests HHV-6B is a common etiologic agent of MTLE. Different virus life cycle may play an important modifying role in inflammatory biology that warrants further investigation. Though virus DNA is difficult detected in CSF, up-regulation of IL-1a and IL-7 in CSF indicates the two cytokines may be taken as indirect biomarker of HHV-6B infection.
Collapse
Affiliation(s)
- Jia-Qi Wang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Hong-Yu Yang
- University of Electronic Science and Technology of China Hospital, China
| | | | - Xin-Yue Jiang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China; Chengdu Second People's Hospital, Chengdu, Sichuan Province, China
| | - Jin-Mei Li
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China.
| |
Collapse
|
5
|
Kawamura Y, Maesawa S, Numoto S, Saito R, Yoshikawa T, Okumura A. Human herpesvirus 6 DNA was not detected in a brain specimen from a patient with mesial temporal sclerosis after status epilepticus due to human herpesvirus 6 infection. Epilepsia Open 2022; 7:817-821. [PMID: 35916714 PMCID: PMC9712467 DOI: 10.1002/epi4.12634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/28/2022] [Indexed: 12/30/2022] Open
Abstract
We performed virological analysis of resected brain tissues from a patient with temporal lobe epilepsy associated with mesial temporal sclerosis after febrile status epilepticus caused by human herpesvirus 6 infection. The patient had febrile status epilepticus at 9 months of age associated with human herpesvirus 6 infection. Magnetic resonance imaging revealed reduced water diffusion in the right temporal lobe and hippocampus. Polymerase chain reaction analysis detected 1.6 × 105 copies/μg of human herpesvirus 6 DNA in whole blood, but none in the cerebrospinal fluid. The patient developed temporal lobe epilepsy associated with mesial temporal sclerosis at 67 months of age, necessitating surgical treatment. Anterior temporal lobectomy was performed at 171 months of age. Real-time polymerase chain reaction analysis of resected brain tissues revealed no viral DNA. In our patient, human herpesvirus 6 infection triggered febrile status epilepticus, while direct evidence to prove contribution of HHV-6 to the development of MTS was not obtained.
Collapse
Affiliation(s)
- Yoshiki Kawamura
- Department of PediatricsFujita Health University School of MedicineAichiJapan
| | - Satoshi Maesawa
- Department of NeurosurgeryNagoya University Graduate School of MedicineAichiJapan
| | - Shingo Numoto
- Department of PediatricsAichi Medical UniversityAichiJapan
| | - Ryuta Saito
- Department of NeurosurgeryNagoya University Graduate School of MedicineAichiJapan
| | - Tetsushi Yoshikawa
- Department of PediatricsFujita Health University School of MedicineAichiJapan
| | | |
Collapse
|
6
|
Löscher W, Howe CL. Molecular Mechanisms in the Genesis of Seizures and Epilepsy Associated With Viral Infection. Front Mol Neurosci 2022; 15:870868. [PMID: 35615063 PMCID: PMC9125338 DOI: 10.3389/fnmol.2022.870868] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/05/2022] [Indexed: 12/16/2022] Open
Abstract
Seizures are a common presenting symptom during viral infections of the central nervous system (CNS) and can occur during the initial phase of infection ("early" or acute symptomatic seizures), after recovery ("late" or spontaneous seizures, indicating the development of acquired epilepsy), or both. The development of acute and delayed seizures may have shared as well as unique pathogenic mechanisms and prognostic implications. Based on an extensive review of the literature, we present an overview of viruses that are associated with early and late seizures in humans. We then describe potential pathophysiologic mechanisms underlying ictogenesis and epileptogenesis, including routes of neuroinvasion, viral control and clearance, systemic inflammation, alterations of the blood-brain barrier, neuroinflammation, and inflammation-induced molecular reorganization of synapses and neural circuits. We provide clinical and animal model findings to highlight commonalities and differences in these processes across various neurotropic or neuropathogenic viruses, including herpesviruses, SARS-CoV-2, flaviviruses, and picornaviruses. In addition, we extensively review the literature regarding Theiler's murine encephalomyelitis virus (TMEV). This picornavirus, although not pathogenic for humans, is possibly the best-characterized model for understanding the molecular mechanisms that drive seizures, epilepsy, and hippocampal damage during viral infection. An enhanced understanding of these mechanisms derived from the TMEV model may lead to novel therapeutic interventions that interfere with ictogenesis and epileptogenesis, even within non-infectious contexts.
Collapse
Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine, Hannover, Germany,Center for Systems Neuroscience, Hannover, Germany,*Correspondence: Wolfgang Löscher,
| | - Charles L. Howe
- Division of Experimental Neurology, Department of Neurology, Mayo Clinic, Rochester, MN, United States,Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, Rochester, MN, United States
| |
Collapse
|
7
|
Mekheal E, Tagliaferri AR, Vasquez KS, Pjetergjoka R, Lobue G, Townsend D, Leou K, Singhal M. A Rare Case of HHV-6 Encephalitis in an Immunocompetent Host: Case Report and Literature Review. Cureus 2022; 14:e23007. [PMID: 35415058 PMCID: PMC8993705 DOI: 10.7759/cureus.23007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2022] [Indexed: 11/19/2022] Open
Abstract
Human herpesvirus-6 (HHV-6) is a virus known for causing the highly contagious infection, roseola infantum, and has been associated with causing encephalitis in pediatric patients and less commonly in adult patients as well. Regardless of the patient's age, the primary HHV-6 infection could be complicated by neurological sequelae including encephalitis, acute encephalopathy with biphasic seizures syndrome, or demyelinating disease. HHV-6 encephalitis does occur in an adult as a primary infection or reactivation. However, immunocompromised, hematopoietic stem cell transplantation patients, and solid organ transplant recipients are the most affected population. Here we present a rare case of HHV-6 encephalitis in a 26-year-old healthy immunocompetent male. HHV-6 viral DNA was detected in the cerebrospinal fluid during the acute stage of the disease, and the diagnosis was confirmed by quantitative polymerase chain reaction (PCR). The patient was treated with ganciclovir and had a complete response to treatment without any further complication. The pathophysiology, clinical course, and treatment in otherwise immunocompetent adult patients are also discussed.
Collapse
|
8
|
Theodore WH, Leibovitch E, Billioux BJ, Inati SK, Zaghloul K, Heiss J, Gaillard WD, Jacobson S. Human herpesvirus 6 and epilepsy. Epilepsia Open 2021; 6:777-780. [PMID: 34324277 PMCID: PMC8633468 DOI: 10.1002/epi4.12531] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 01/12/2023] Open
Abstract
We investigated the association between human herpesvirus 6 (HHV‐6) and mesial temporal sclerosis (MTS) in 87 patients who had surgery for drug‐resistant epilepsy. Fifty‐four had MTS, 22 focal cortical dysplasia (FCD), four tumors, three vascular malformations, and three a history of encephalitis. We extracted DNA from fresh brain tissue immediately after surgery and performed viral detection with quantitative real‐time polymerase chain reaction (PCR) or digital droplet PCR specific for HHV‐6A and HHV‐6B. Tissue was studied with standard clinical techniques, including hematoxylin and eosin, glial fibrillary acidic protein, and NeuN stains. Twenty‐nine of 54 patients with MTS, six of 23 with focal cortical dysplasia (FCD), and one of three with a history of encephalitis were positive for HHV‐6 (P < .02). Febrile seizure history was not associated with HHV‐6 detection. Patients with MTS had significantly lower seizure onset age than those with other pathologies. Thirteen patients had positron emission tomography with [11C]PBR28, a marker for reactive astrocytes and activated microglia; there was a trend for HHV‐6‐positive patients to have higher binding in their seizure foci, suggesting inflammation. Our study supports a potential role for HHV‐6 in the etiology of MTS.
Collapse
Affiliation(s)
- William H Theodore
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Emily Leibovitch
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Bridgette J Billioux
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Sara K Inati
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Kareem Zaghloul
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - John Heiss
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - William D Gaillard
- Department of Neurology, Children's National Medical Center, Washington, DC, USA
| | - Steven Jacobson
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| |
Collapse
|
9
|
Analysis of autoantibody spectrum and human herpesvirus 6 in adult patients with 'early' versus 'late' diagnosis of 'possible limbic encephalitis'. Epilepsy Res 2021; 176:106698. [PMID: 34246119 DOI: 10.1016/j.eplepsyres.2021.106698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 06/11/2021] [Accepted: 06/19/2021] [Indexed: 11/22/2022]
Abstract
New onset temporal seizures are increasingly encountered in adult patients. Many of those fulfill diagnostic criteria for possible or definite limbic encephalitis (LE). LE is associated with autoantibodies (autoABs) against neuronal surface structures ('neuronal' autoABs), 'onconeuronal' or GAD65. AutoABs can emerge in a paraneoplastic setting. However, by far not all patients with possible/definite LE have an oncological history. AutoABs have also found to arise in the context of viral encephalitis. Rare associations between autoAB-positive LE and human herpes virus 6 (HHV-6) infection have been as well reported. Our present analysis was dedicated to learn about potentially different autoAB spectra and HHV-6 detection rates in adult-onset temporal seizure patients with possible LE and largely different time spans between first seizure events and referral to a tertiary epileptological center due to pharmacoresistent seizures. We scrutinized serum/CSF samples obtained from adults with 'early diagnosis' of possible LE (≤ 30 months after first seizure event; n = 94) versus a patient group with 'late diagnosis' of possible LE (≥ 97 months; n = 45) for the presence of autoABs and HHV-6 DNA. AutoABs were detected in CSF and/or serum samples (n = 20) in 21.3 % of the early diagnosis patients with the highest abundance of anti-LGI1 (n = 8), significantly more frequent than in the late diagnosis group (autoAB positive: n = 4 (8.9 %); *p < 0.05, Fisher's Exact Test). Quantitative PCR revealed viral HHV-6 DNA in only one serum sample of the early diagnosis cohort but no evidence in corresponding CSF samples or in any sample of the late diagnosis group. The present data demonstrate a higher incidence of distinct autoABs in adults with early diagnosis of possible LE. The distinct spectra of autoABs have to be taken into account in the differential diagnosis of possible LE patients with short versus more sustained duration of temporal seizure activity.
Collapse
|
10
|
Abstract
Numerous studies have identified microbial sequences or epitopes in pathological and non-pathological human brain samples. It has not been resolved if these observations are artifactual, or truly represent population of the brain by microbes. Given the tempting speculation that resident microbes could play a role in the many neuropsychiatric and neurodegenerative diseases that currently lack clear etiologies, there is a strong motivation to determine the “ground truth” of microbial existence in living brains. Here I argue that the evidence for the presence of microbes in diseased brains is quite strong, but a compelling demonstration of resident microbes in the healthy human brain remains to be done. Dedicated animal models studies may be required to determine if there is indeed a “brain microbiome.”
Collapse
Affiliation(s)
- Christopher D Link
- Department of Integrative Physiology/Institute for Behavioral Genetics, University of Colorado, Boulder, Boulder, CO, USA
| |
Collapse
|
11
|
Abstract
AbstractHuman herpes virus 6 (HHV-6) is a ubiquitous and most common pathogen that affects humans. Human herpes virus 6B (HHV-6B) is a wide spread human herpesvirus that infects most people when they are children, establishes latent infections in the central nervous system (CNS), especially in the hippocampus and amygdala, and induces neurologic diseases. HHV-6 can establish a latent infection and be reactivated by various stimuli. Recently, viral genomic DNA of HHV-6B has been detected in surgically removed brain tissues of intractable epilepsy patients, suggesting the involvement of HHV-6B in the pathogenesis of epilepsy. Temporal lobe epilepsy (TLE) has been shown to be closely related with HHV-6B. TLE patients with HHV-6B in their brains suffer from reiterative attacks of febrile seizures and hippocampal sclerosis. However, the mechanisms underlying the contribution of this virus to the development of TLE remains unknown. The direct damage and immune activation caused by the virus are involved in the process of neuron damage, abnormal neural circuit formation and glial cell proliferation. In addition, some cytokines like interleukin-17A (IL-17A), nuclear factor-kappa B (NF-κb), transforming growth factor-β (TGF-β), mitogen-activated protein kinase (MAPK) and phospholipase A2 are up-regulated and involved in the pathological process of TLE. More studies are needed to clarify the mechanisms underlying the link between HHV-6B and epilepsy, and identify biomarkers to recognize different patient groups for anti-inflammatory or immunomodulatory therapies.
Collapse
|
12
|
Komaroff AL, Pellett PE, Jacobson S. Human Herpesviruses 6A and 6B in Brain Diseases: Association versus Causation. Clin Microbiol Rev 2020; 34:e00143-20. [PMID: 33177186 PMCID: PMC7667666 DOI: 10.1128/cmr.00143-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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
|
13
|
Santpere G, Telford M, Andrés-Benito P, Navarro A, Ferrer I. The Presence of Human Herpesvirus 6 in the Brain in Health and Disease. Biomolecules 2020; 10:E1520. [PMID: 33172107 PMCID: PMC7694807 DOI: 10.3390/biom10111520] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 01/03/2023] Open
Abstract
The human herpesvirus 6 (HHV-6) -A and -B are two dsDNA beta-herpesviruses infectingalmost the entire worldwide population. These viruses have been implicated in multipleneurological conditions in individuals of various ages and immunological status, includingencephalitis, epilepsy, and febrile seizures. HHV-6s have also been suggested as playing a role inthe etiology of neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease. Theapparent robustness of these suggested associations is contingent on the accuracy of HHV-6detection in the nervous system. The effort of more than three decades of researching HHV-6 in thebrain has yielded numerous observations, albeit using variable technical approaches in terms oftissue preservation, detection techniques, sample sizes, brain regions, and comorbidities. In thisreview, we aimed to summarize current knowledge about the entry routes and direct presence ofHHV-6 in the brain parenchyma at the level of DNA, RNA, proteins, and specific cell types, inhealthy subjects and in those with neurological conditions. We also discuss recent findings relatedto the presence of HHV-6 in the brains of patients with Alzheimer's disease in light of availableevidence.
Collapse
Affiliation(s)
- Gabriel Santpere
- Neurogenomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM), DCEXS, Universitat Pompeu Fabra, 08003 Barcelona, Catalonia, Spain
| | - Marco Telford
- Institute of Evolutionary Biology (UPF-CSIC), Departament de Ciències Experimentals i la Salut, Universitat Pompeu Fabra, PRBB, 08003 Barcelona, Catalonia, Spain; (M.T.); (A.N.)
| | - Pol Andrés-Benito
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Arcadi Navarro
- Institute of Evolutionary Biology (UPF-CSIC), Departament de Ciències Experimentals i la Salut, Universitat Pompeu Fabra, PRBB, 08003 Barcelona, Catalonia, Spain; (M.T.); (A.N.)
- Catalan Institution of Research and Advanced Studies (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Carrer del Dr. Aiguader 88, 08003 Barcelona, Spain
- Barcelonaβeta Brain Research Center (BBRC), Pasqual Maragall Foundation, Wellington 30, 08005 Barcelona, Spain
| | - Isidre Ferrer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Hospitalet de Llobregat, 08907 Barcelona, Spain
- Bellvitge University Hospital, IDIBELL (Bellvitge Biomedical Research Centre), Hospitalet de Llobregat, 08908 Barcelona, Spain
| |
Collapse
|
14
|
Dunn N, Kharlamova N, Fogdell-Hahn A. The role of herpesvirus 6A and 6B in multiple sclerosis and epilepsy. Scand J Immunol 2020; 92:e12984. [PMID: 33037649 PMCID: PMC7757173 DOI: 10.1111/sji.12984] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/11/2020] [Accepted: 10/05/2020] [Indexed: 01/07/2023]
Abstract
Human herpesvirus 6A (HHV‐6A) and 6B (HHV‐6B) are two closely related viruses that can infect cells of the central nervous system (CNS). The similarities between these viruses have made it difficult to separate them on serological level. The broad term HHV‐6 remains when referring to studies where the two species were not distinguished, and as such, the seroprevalence is over 90% in the adult population. HHV‐6B has been detected in up to 100% of infants with the primary infection roseola infantum, but less is known about the primary infection of HHV‐6A. Both viruses are neurotropic and have capacity to establish lifelong latency in cells of the central nervous system, with potential to reactivate and cause complications later in life. HHV‐6A infection has been associated with an increased risk of multiple sclerosis (MS), whereas HHV‐6B is indicated to be involved in pathogenesis of epilepsy. These two associations show how neurological diseases might be caused by viral infections, but as suggested here, through completely different molecular mechanisms, in an autoimmune disease, such as MS, by triggering an overreaction of the immune system and in epilepsy by hampering internal cellular functions when the immune system fails to eliminate the virus. Understanding the viral mechanisms of primary infection and reactivation and their spectrum of associated symptoms will aid our ability to diagnose, treat and prevent these severe and chronic diseases. This review explores the role of HHV‐6A and HHV‐6B specifically in MS and epilepsy, the evidence to date and the future directions of this field.
Collapse
Affiliation(s)
- Nicky Dunn
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Stockholm, Sweden
| | - Nastya Kharlamova
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Stockholm, Sweden
| | - Anna Fogdell-Hahn
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Stockholm, Sweden
| |
Collapse
|
15
|
Akinsoji EO, Leibovitch E, Billioux BJ, Abath Neto OL, Ray-Chaudhury A, Inati SK, Zaghloul K, Heiss J, Jacobson S, Theodore WH. HHV-6 and hippocampal volume in patients with mesial temporal sclerosis. Ann Clin Transl Neurol 2020; 7:1674-1680. [PMID: 33325656 PMCID: PMC7480901 DOI: 10.1002/acn3.51152] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/16/2020] [Indexed: 12/11/2022] Open
Abstract
Objective To study the effects of human herpes virus 6 (HHV‐6) on the hippocampal volume in patients with mesial temporal sclerosis (MTS). Background HHV‐6 may play an etiologic role in MTS. Previous studies found a possible association with febrile status epilepticus. Several investigators have reported a higher prevalence of HHV‐6 in MTS resections compared to other epilepsy etiologies. Design/Methods We used FreeSurfer to segment cortical structures and obtain whole hippocampal and subfield volumes in 41 patients with intractable epilepsy. In addition, an investigator blinded to other data traced hippocampi manually on each slice. The main study outcome measure was the asymmetry index (AI) between hippocampal volumes ipsilateral and contralateral to seizure foci compared between HHV‐6 positive and negative patients. Viral DNA was isolated from fresh brain tissue obtained at temporal lobectomy. For 25 patients, viral detection was performed using quantitative real‐time PCR specific for HHV‐6A and HHV‐6B. For 16 patients, viral DNA detection was performed using digital droplet PCR specific for HHV‐6A and HHV‐6B. Results Twenty‐two patients were positive (14 of 25 tested with real‐time PCR, and 8 of 16 with digital droplet PCR), and 19 negatives for HHV‐6. HHV‐6 negative patients had significantly greater AI and lower total hippocampal volume ipsilateral to seizure foci than HHV‐6 positive patients. Epilepsy duration and age of onset did not affect results. Interpretation Our data suggest multiple potential etiologies for MTS. HHV‐6 may have a less severe effect on the hippocampus than other etiologies.
Collapse
Affiliation(s)
- Elizabeth O Akinsoji
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - Emily Leibovitch
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - B Jeanne Billioux
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - Osorio Lopes Abath Neto
- National Institute of Neurological Disorders and Stroke, National Cancer Institute, NIH, Bethesda, Maryland
| | - Abhik Ray-Chaudhury
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - Sara K Inati
- EEG Laboratory, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - Kareem Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - John Heiss
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - Steven Jacobson
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - William H Theodore
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| |
Collapse
|
16
|
Lathe R, St Clair D. From conifers to cognition: Microbes, brain and behavior. GENES BRAIN AND BEHAVIOR 2020; 19:e12680. [PMID: 32515128 DOI: 10.1111/gbb.12680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 12/25/2022]
Abstract
A diversity of bacteria, protozoans and viruses ("endozoites") were recently uncovered within healthy tissues including the human brain. By contrast, it was already recognized a century ago that healthy plants tissues contain abundant endogenous microbes ("endophytes"). Taking endophytes as an informative precedent, we overview the nature, prevalence, and role of endozoites in mammalian tissues, centrally focusing on the brain, concluding that endozoites are ubiquitous in diverse tissues. These passengers often remain subclinical, but they are not silent. We address their routes of entry, mechanisms of persistence, tissue specificity, and potential to cause long-term behavioral changes and/or immunosuppression in mammals, where rabies virus is the exemplar. We extend the discussion to Herpesviridae, Coronaviridae, and Toxoplasma, as well as to diverse bacteria and yeasts, and debate the advantages and disadvantages that endozoite infection might afford to the host and to the ecosystem. We provide a clinical perspective in which endozoites are implicated in neurodegenerative disease, anxiety/depression, and schizophrenia. We conclude that endozoites are instrumental in the delicate balance between health and disease, including age-related brain disease, and that endozoites have played an important role in the evolution of brain function and human behavior.
Collapse
Affiliation(s)
- Richard Lathe
- Division of Infection Medicine, University of Edinburgh Medical School, Edinburgh, UK
| | - David St Clair
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
| |
Collapse
|
17
|
Persistent Roseoloviruses Infection in Adult Patients with Epilepsy. Brain Sci 2020; 10:brainsci10050287. [PMID: 32403392 PMCID: PMC7288180 DOI: 10.3390/brainsci10050287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 12/31/2022] Open
Abstract
Background: Human herpesviruses (HHV)-6A, HHV-6B and HHV-7 are considered to be involved in the pathogenesis of epilepsy, a common neurological disorder. The objective of this study was to determine the association of roseoloviruses infection with epilepsy. Methods: 53 epilepsy patients and 104 ordinary blood donors were analyzed to determine presence of virus-specific antibodies by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA), genomic sequences, viral load and gene expression by polymerase chain reactions (PCRs) and restriction analysis, HHV-6 protein expression by IFA and level of cytokines by ELISA. Results: Roseoloviruses genomic sequences in DNA samples from whole blood were found in 86.8% of patients versus 54.8% of controls and active infection was revealed only in patients with epilepsy (19.6% of roseolovirus-positive patients). Significantly higher viral load and more frequent gene expression was detected in patients compared to the controls. HHV-6-encoded protein expression was demonstrated in 53.3% of patients with previously detected HHV-6 DNA. Changes in level of cytokines were determined in patients with elevated viral load compared to the patients without elevated viral loads and to the controls. Conclusions: Results on frequent active HHV-6 and HHV-7 infection in epilepsy patient’ peripheral blood indicate on possible involvement of these viruses in the disease development.
Collapse
|
18
|
Allnutt MA, Johnson K, Bennett DA, Connor SM, Troncoso JC, Pletnikova O, Albert MS, Resnick SM, Scholz SW, De Jager PL, Jacobson S. Human Herpesvirus 6 Detection in Alzheimer's Disease Cases and Controls across Multiple Cohorts. Neuron 2020; 105:1027-1035.e2. [PMID: 31983538 PMCID: PMC7182308 DOI: 10.1016/j.neuron.2019.12.031] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/11/2019] [Accepted: 12/26/2019] [Indexed: 01/03/2023]
Abstract
The interplay between viral infection and Alzheimer's disease (AD) has long been an area of interest, but proving causality has been elusive. Several recent studies have renewed the debate concerning the role of herpesviruses, and human herpesvirus 6 (HHV-6) in particular, in AD. We screened for HHV-6 detection across three independent AD brain repositories using (1) RNA sequencing (RNA-seq) datasets and (2) DNA samples extracted from AD and non-AD control brains. The RNA-seq data were screened for pathogens against taxon references from over 25,000 microbes, including 118 human viruses, whereas DNA samples were probed for PCR reactivity to HHV-6A and HHV-6B. HHV-6 demonstrated little specificity to AD brains over controls by either method, whereas other viruses, such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV), were detected at comparable levels. These direct methods of viral detection do not suggest an association between HHV-6 and AD.
Collapse
Affiliation(s)
- Mary Alice Allnutt
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20814, USA
| | - Kory Johnson
- Bioinformatics Section, Information Technology & Bioinformatics Program, Division of Intramural Research (DIR), National Institute of Neurological Disorders and Stroke/National Institute of Health, Bethesda, MD 20814, USA
| | - David A Bennett
- Alzheimer Disease Center, RUSH University, Chicago, IL 60612, USA
| | - Sarah M Connor
- Center for Translational & Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Juan C Troncoso
- Department of Pathology (Neuropathology), Johns Hopkins University Medical Center, Baltimore, MD 21205, USA
| | - Olga Pletnikova
- Department of Pathology (Neuropathology), Johns Hopkins University Medical Center, Baltimore, MD 21205, USA
| | - Marilyn S Albert
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Sonja W Scholz
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Neurodegenerative Diseases Research Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20814, USA
| | - Philip L De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Steven Jacobson
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20814, USA.
| |
Collapse
|
19
|
Asadi-Pooya AA, Bartolini L. Prevention and treatment of temporal lobe epilepsy: lessons from hepatitis B story! Int J Neurosci 2020; 130:1151-1155. [PMID: 32053411 DOI: 10.1080/00207454.2020.1730370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy and hippocampal sclerosis (HS) is the most common pathological substrate of TLE. Considering the significant consequences of uncontrolled seizures (e.g. increased morbidity and mortality), epilepsy prevention remains a necessity that potentially could save many lives. Human herpes virus-6 (HHV-6) has been linked to TLE in humans. The relationship between HHV-6 and HS-TLE could be attributed to a neuro-inflammatory cascade triggered by the infection, involving direct neuronal damage and production of several pro-inflammatory cytokines under certain conditions that are still incompletely understood. Hepatitis B virus (HBV) infection is another chronic viral infection with a life-long latency. HBV infection is linked to various clinical conditions, including liver cirrhosis. There are currently three ways to fight HBV infection and its consequences; primary prevention (by vaccination), secondary prevention (by drug therapy), and tertiary prevention (by liver transplantation). Considering the similarities between the natural histories of HHV-6 and HBV infections, and also the successful strategies which are currently available to fight HBV infection and its long-term consequences, here, we propose three strategies to fight HHV-6 and its possible long-term consequence (i.e. HS-TLE): Primary prevention: by developing vaccines to prevent HHV-6 infection; Secondary prevention: by considering trials of antiviral drugs to treat HHV-6 infection, when it happens in the childhood to hopefully prevent its long-term consequences; and, Tertiary prevention: by stem cell therapy for drug-resistant epilepsy.
Collapse
Affiliation(s)
- Ali A Asadi-Pooya
- Epilepsy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Jefferson Comprehensive Epilepsy Center, Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Luca Bartolini
- Hasbro Children's Hospital/Alpert Medical School of Brown University, Providence, RI, USA
| |
Collapse
|
20
|
Lum GR, Olson CA, Hsiao EY. Emerging roles for the intestinal microbiome in epilepsy. Neurobiol Dis 2020; 135:104576. [PMID: 31445165 DOI: 10.1016/j.nbd.2019.104576] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/29/2019] [Accepted: 08/14/2019] [Indexed: 02/07/2023] Open
Abstract
The gut microbiome is emerging as a key regulator of brain function and behavior and is associated with symptoms of several neurological disorders. There is emerging evidence that alterations in the gut microbiota are seen in epilepsy and in response to seizure interventions. In this review, we highlight recent studies reporting that individuals with refractory epilepsy exhibit altered composition of the gut microbiota. We further discuss antibiotic treatment and infection as microbiome-related factors that influence seizure susceptibility in humans and animal models. In addition, we evaluate how the microbiome may mediate effects of the ketogenic diet, probiotic treatment, and anti-epileptic drugs on reducing both seizure frequency and severity. Finally, we assess the open questions in interrogating roles for the microbiome in epilepsy and address the prospect that continued research may uncover fundamental insights for understanding risk factors for epilepsy, as well as novel approaches for treating refractory epilepsy.
Collapse
Affiliation(s)
- Gregory R Lum
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christine A Olson
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elaine Y Hsiao
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
21
|
Bartolini L, Theodore WH, Jacobson S, Gaillard WD. Infection with HHV-6 and its role in epilepsy. Epilepsy Res 2019; 153:34-39. [DOI: 10.1016/j.eplepsyres.2019.03.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/18/2019] [Accepted: 03/24/2019] [Indexed: 01/09/2023]
|
22
|
Itzhaki RF. Corroboration of a Major Role for Herpes Simplex Virus Type 1 in Alzheimer's Disease. Front Aging Neurosci 2018; 10:324. [PMID: 30405395 PMCID: PMC6202583 DOI: 10.3389/fnagi.2018.00324] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 09/25/2018] [Indexed: 01/10/2023] Open
Abstract
Strong evidence has emerged recently for the concept that herpes simplex virus type 1 (HSV1) is a major risk for Alzheimer’s disease (AD). This concept proposes that latent HSV1 in brain of carriers of the type 4 allele of the apolipoprotein E gene (APOE-ε4) is reactivated intermittently by events such as immunosuppression, peripheral infection, and inflammation, the consequent damage accumulating, and culminating eventually in the development of AD. Population data to investigate this epidemiologically, e.g., to find if subjects treated with antivirals might be protected from developing dementia—are available in Taiwan, from the National Health Insurance Research Database, in which 99.9% of the population has been enrolled. This is being extensively mined for information on microbial infections and disease. Three publications have now appeared describing data on the development of senile dementia (SD), and the treatment of those with marked overt signs of disease caused by varicella zoster virus (VZV), or by HSV. The striking results show that the risk of SD is much greater in those who are HSV-seropositive than in seronegative subjects, and that antiviral treatment causes a dramatic decrease in number of subjects who later develop SD. It should be stressed that these results apply only to those with severe cases of HSV1 or VZV infection, but when considered with the over 150 publications that strongly support an HSV1 role in AD, they greatly justify usage of antiherpes antivirals to treat AD. Three other studies are described which directly relate to HSV1 and AD: they deal respectively with lysosomal changes in HSV1-infected cell cultures, with evidence for a role of human herpes virus type 6 and 7 (HHV6 and HHV7) in AD, and viral effects on host gene expression, and with the antiviral characteristics of beta amyloid (Aβ). Three indirectly relevant studies deal respectively with schizophrenia, relating to antiviral treatment to target HSV1, with the likelihood that HSV1 is a cause of fibromyalgia (FM), and with FM being associated with later development of SD. Studies on the link between epilepsy, AD and herpes simplex encephalitis (HSE) are described also, as are the possible roles of APOE-ε4, HHV6 and HSV1 in epilepsy.
Collapse
Affiliation(s)
- Ruth F Itzhaki
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
23
|
Engdahl E, Niehusmann P, Fogdell-Hahn A. The effect of human herpesvirus 6B infection on the MAPK pathway. Virus Res 2018; 256:134-141. [PMID: 30130603 DOI: 10.1016/j.virusres.2018.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/03/2018] [Accepted: 08/16/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Human herpesvirus 6B (HHV-6B) is a neurotropic virus that has been repeatedly associated with mesial temporal lobe epilepsy (MTLE). However, the mechanism behind this suggested association is not known. Therefore, the aim of this study was to investigate what genes were affected by HHV-6B, possibly revealing HHV-6B induced disease causing mechanisms. MATERIAL AND METHOD First, gene expression in MTLE tissue positive for HHV-6B DNA (n = 10) and negative for HHV-6B DNA (n = 14) was compared using the Affymetrix® Human Gene 2.1 ST Array. Secondly, in vitro experiments were conducted where Molt-3 T cells were infected with HHV-6B and gene expression of MAP2K4 (MKK4) and 89 other genes in the MAPK signaling pathway was investigated using qPCR. In addition, phosphorylated MKK4 was assessed using IFA and the DNA methylation investigated with Illumina Infinium HumanMethylation450 BeadChip array. RESULTS MAP2K4 was one of the most differently expressed genes in the Affymetrix array, suggesting an upregulation by HHV-6B infection in MTLE tissue. No gene reached statistical significance but MAP2K4 was selected for further investigation in vitro, where it was clearly upregulated by HHV-6B infection both on gene expression and protein expression level. Further investigating expression of genes in the MAPK pathways in vitro revealed that several genes were affected by HHV-6B infection, but none of these genes displayed viral induced changes in DNA methylation. CONCLUSIONS As the MAPK pathways are involved in transforming different stimuli (like stress) into a cellular responses (like apoptosis or inflammation), it may not be surprising that genes in these pathways are affected by virus infection. This is the first report of HHV-6B's effect on these signaling cascades and given that both dysregulation of the MAPK pathways and an association with HHV-6B have been previously observed in epilepsy, a possible link of infection induced dysregulation of MAPK in epilepsy warrant further investigation.
Collapse
Affiliation(s)
- Elin Engdahl
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Pitt Niehusmann
- Department of Neurology/Pathology, Oslo University Hospital, 0450, Oslo, Norway; Department of Neuropathology, University of Bonn Medical Center, 53113, Bonn, Germany
| | - Anna Fogdell-Hahn
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| |
Collapse
|
24
|
Autistic traits in epilepsy models: Why, when and how? Epilepsy Res 2018; 144:62-70. [PMID: 29783181 DOI: 10.1016/j.eplepsyres.2018.05.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/18/2018] [Accepted: 05/14/2018] [Indexed: 12/27/2022]
Abstract
Autism spectrum disorder (ASD) is a common comorbidity of epilepsy and seizures and/or epileptiform activity are observed in a significant proportion of ASD patients. Current research also implies that autistic traits can be observed to a various degree in mice and rats with seizures. This suggests that there are shared mechanisms in both ASD and epilepsy syndromes. Here, we first review the standard, validated methods used to assess autistic traits in animal models as well as their limitations with regards to epilepsy models. We then discuss two of the potential pathological processes that could be shared between ASD and epilepsy. We first focus on functional implications of neuroinflammation including changes to excitable networks mediated by inflammatory regulators. Finally we examine mechanisms at the cellular and network level involved in neuronal excitability, timing and network coordination that may directly lead to behavioral disturbances present in both epilepsy and ASD. This mini-review summarizes the work first presented at an Investigators Workshop at the 2016 American Epilepsy Society meeting.
Collapse
|