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Circadian and Brain State Modulation of Network Hyperexcitability in Alzheimer's Disease. eNeuro 2018; 5:eN-CFN-0426-17. [PMID: 29780880 PMCID: PMC5956746 DOI: 10.1523/eneuro.0426-17.2018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/08/2018] [Accepted: 04/06/2018] [Indexed: 01/08/2023] Open
Abstract
Network hyperexcitability is a feature of Alzheimer' disease (AD) as well as numerous transgenic mouse models of AD. While hyperexcitability in AD patients and AD animal models share certain features, the mechanistic overlap remains to be established. We aimed to identify features of network hyperexcitability in AD models that can be related to epileptiform activity signatures in AD patients. We studied network hyperexcitability in mice expressing amyloid precursor protein (APP) with mutations that cause familial AD, and compared a transgenic model that overexpresses human APP (hAPP) (J20), to a knock-in model expressing APP at physiological levels (APPNL/F). We recorded continuous long-term electrocorticogram (ECoG) activity from mice, and studied modulation by circadian cycle, behavioral, and brain state. We report that while J20s exhibit frequent interictal spikes (IISs), APPNL/F mice do not. In J20 mice, IISs were most prevalent during daylight hours and the circadian modulation was associated with sleep. Further analysis of brain state revealed that IIS in J20s are associated with features of rapid eye movement (REM) sleep. We found no evidence of cholinergic changes that may contribute to IIS-circadian coupling in J20s. In contrast to J20s, intracranial recordings capturing IIS in AD patients demonstrated frequent IIS in non-REM (NREM) sleep. The salient differences in sleep-stage coupling of IIS in APP overexpressing mice and AD patients suggests that different mechanisms may underlie network hyperexcitability in mice and humans. We posit that sleep-stage coupling of IIS should be an important consideration in identifying mouse AD models that most closely recapitulate network hyperexcitability in human AD.
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302
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Amyloid causes intermittent network disruptions in cognitively intact older subjects. Brain Imaging Behav 2018; 13:699-716. [DOI: 10.1007/s11682-018-9869-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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303
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Beagle AJ, Darwish SM, Ranasinghe KG, La AL, Karageorgiou E, Vossel KA. Relative Incidence of Seizures and Myoclonus in Alzheimer's Disease, Dementia with Lewy Bodies, and Frontotemporal Dementia. J Alzheimers Dis 2018; 60:211-223. [PMID: 28826176 DOI: 10.3233/jad-170031] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Patients with Alzheimer's disease (AD) are more prone to seizures and myoclonus, but relative risk of these symptoms among other dementia types is unknown. OBJECTIVE To determine incidence of seizures and myoclonus in the three most common neurodegenerative dementias: AD, dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD). METHODS Our institution's medical records were reviewed for new-onset unprovoked seizures and myoclonus in patients meeting criteria for AD (n = 1,320), DLB (n = 178), and FTD (n = 348). Cumulative probabilities of developing seizures and myoclonus were compared between diagnostic groups, whereas age-stratified incidence rates were determined relative to control populations. RESULTS The cumulative probability of developing seizures after disease onset was 11.5% overall, highest in AD (13.4%) and DLB (14.7%) and lowest in FTD (3.0%). The cumulative probability of developing myoclonus was 42.1% overall, highest in DLB (58.1%). The seizure incidence rates, relative to control populations, were nearly 10-fold in AD and DLB, and 6-fold in FTD. Relative seizure rates increased with earlier age-at-onset in AD (age <50, 127-fold; 50-69, 21-fold; 70+, 2-fold) and FTD (age <50, 53-fold; 50-69, 9-fold), and relative myoclonus rates increased with earlier age-at-onset in all groups. Seizures began an average of 3.9 years after the onset of cognitive or motor decline, and myoclonus began 5.4 years after onset. CONCLUSIONS Seizures and myoclonus occur with greater incidence in patients with AD, DLB, and FTD than in the general population, but rates vary with diagnosis, suggesting varied pathomechanisms of network hyperexcitability. Patients often experience these symptoms early in disease, suggesting hyperexcitability could be an important target for interventions.
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Affiliation(s)
- Alexander J Beagle
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Sonja M Darwish
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Kamalini G Ranasinghe
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Alice L La
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Elissaios Karageorgiou
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA.,Neurological Institute of Athens, Athens, Greece
| | - Keith A Vossel
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA.,N. Bud Grossman Center for Memory Research and Care, Institute for Translational Neuroscience, and Department of Neurology, University of Minnesota, Minneapolis, MN, USA
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304
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Reichenbach N, Delekate A, Breithausen B, Keppler K, Poll S, Schulte T, Peter J, Plescher M, Hansen JN, Blank N, Keller A, Fuhrmann M, Henneberger C, Halle A, Petzold GC. P2Y1 receptor blockade normalizes network dysfunction and cognition in an Alzheimer's disease model. J Exp Med 2018; 215:1649-1663. [PMID: 29724785 PMCID: PMC5987918 DOI: 10.1084/jem.20171487] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 02/12/2018] [Accepted: 04/12/2018] [Indexed: 11/04/2022] Open
Abstract
Astrocytic hyperactivity is an important contributor to neuronal-glial network dysfunction in Alzheimer's disease (AD). We have previously shown that astrocyte hyperactivity is mediated by signaling through the P2Y1 purinoreceptor (P2Y1R) pathway. Using the APPPS1 mouse model of AD, we here find that chronic intracerebroventricular infusion of P2Y1R inhibitors normalizes astroglial and neuronal network dysfunction, as measured by in vivo two-photon microscopy, augments structural synaptic integrity, and preserves hippocampal long-term potentiation. These effects occur independently from β-amyloid metabolism or plaque burden but are associated with a higher morphological complexity of periplaque reactive astrocytes, as well as reduced dystrophic neurite burden and greater plaque compaction. Importantly, APPPS1 mice chronically treated with P2Y1R antagonists, as well as APPPS1 mice carrying an astrocyte-specific genetic deletion (Ip3r2-/-) of signaling pathways downstream of P2Y1R activation, are protected from the decline of spatial learning and memory. In summary, our study establishes the restoration of network homoeostasis by P2Y1R inhibition as a novel treatment target in AD.
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Affiliation(s)
| | | | - Björn Breithausen
- Institute of Cellular Neurosciences, University Hospital Bonn, Bonn, Germany
| | - Kevin Keppler
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Stefanie Poll
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | | | - Jan Peter
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | | | - Jan N Hansen
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Nelli Blank
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Armin Keller
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | | | - Christian Henneberger
- German Center for Neurodegenerative Diseases, Bonn, Germany.,Institute of Cellular Neurosciences, University Hospital Bonn, Bonn, Germany.,Institute of Neurology, University College London, London, England, UK
| | - Annett Halle
- German Center for Neurodegenerative Diseases, Bonn, Germany.,Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases, Bonn, Germany .,Department of Neurology, University Hospital Bonn, Bonn, Germany
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305
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Corbett BF, You JC, Zhang X, Pyfer MS, Tosi U, Iascone DM, Petrof I, Hazra A, Fu CH, Stephens GS, Ashok AA, Aschmies S, Zhao L, Nestler EJ, Chin J. ΔFosB Regulates Gene Expression and Cognitive Dysfunction in a Mouse Model of Alzheimer's Disease. Cell Rep 2018; 20:344-355. [PMID: 28700937 DOI: 10.1016/j.celrep.2017.06.040] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/15/2017] [Accepted: 06/15/2017] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by cognitive decline and 5- to 10-fold increased seizure incidence. How seizures contribute to cognitive decline in AD or other disorders is unclear. We show that spontaneous seizures increase expression of ΔFosB, a highly stable Fos-family transcription factor, in the hippocampus of an AD mouse model. ΔFosB suppressed expression of the immediate early gene c-Fos, which is critical for plasticity and cognition, by binding its promoter and triggering histone deacetylation. Acute histone deacetylase (HDAC) inhibition or inhibition of ΔFosB activity restored c-Fos induction and improved cognition in AD mice. Administration of seizure-inducing agents to nontransgenic mice also resulted in ΔFosB-mediated suppression of c-Fos, suggesting that this mechanism is not confined to AD mice. These results explain observations that c-Fos expression increases after acute neuronal activity but decreases with chronic activity. Moreover, these results indicate a general mechanism by which seizures contribute to persistent cognitive deficits, even during seizure-free periods.
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Affiliation(s)
- Brian F Corbett
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Jason C You
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Xiaohong Zhang
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Mark S Pyfer
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Umberto Tosi
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Daniel M Iascone
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Iraklis Petrof
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Anupam Hazra
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Chia-Hsuan Fu
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gabriel S Stephens
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Annie A Ashok
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Suzan Aschmies
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Lijuan Zhao
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Eric J Nestler
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jeannie Chin
- Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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306
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Gardner RC, Dams-O'Connor K, Morrissey MR, Manley GT. Geriatric Traumatic Brain Injury: Epidemiology, Outcomes, Knowledge Gaps, and Future Directions. J Neurotrauma 2018; 35:889-906. [PMID: 29212411 PMCID: PMC5865621 DOI: 10.1089/neu.2017.5371] [Citation(s) in RCA: 244] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
This review of the literature on traumatic brain injury (TBI) in older adults focuses on incident TBI sustained in older adulthood ("geriatric TBI") rather than on the separate, but related, topic of older adults with a history of earlier-life TBI. We describe the epidemiology of geriatric TBI, the impact of comorbidities and pre-injury function on TBI risk and outcomes, diagnostic testing, management issues, outcomes, and critical directions for future research. The highest incidence of TBI-related emergency department visits, hospitalizations, and deaths occur in older adults. Higher morbidity and mortality rates among older versus younger individuals with TBI may contribute to an assumption of futility about aggressive management of geriatric TBI. However, many older adults with TBI respond well to aggressive management and rehabilitation, suggesting that chronological age and TBI severity alone are inadequate prognostic markers. Yet there are few geriatric-specific TBI guidelines to assist with complex management decisions, and TBI prognostic models do not perform optimally in this population. Major barriers in management of geriatric TBI include under-representation of older adults in TBI research, lack of systematic measurement of pre-injury health that may be a better predictor of outcome and response to treatment than age and TBI severity alone, and lack of geriatric-specific TBI common data elements (CDEs). This review highlights the urgent need to develop more age-inclusive TBI research protocols, geriatric TBI CDEs, geriatric TBI prognostic models, and evidence-based geriatric TBI consensus management guidelines aimed at improving short- and long-term outcomes for the large and growing geriatric TBI population.
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Affiliation(s)
- Raquel C. Gardner
- Department of Neurology, University of California San Francisco, and San Francisco VA Medical Center, San Francisco, California
- University of California San Francisco Weill Institute for Neurosciences, San Francisco, California
| | - Kristen Dams-O'Connor
- Department of Rehabilitation Medicine, Icahn School of Medicine at Mt. Sinai, New York, New York
| | - Molly Rose Morrissey
- Department of Neurosurgery, Brain and Spinal Injury Center, University of California San Francisco and Zuckerberg San Francisco General Hospital, San Francisco, California
| | - Geoffrey T. Manley
- University of California San Francisco Weill Institute for Neurosciences, San Francisco, California
- Department of Neurosurgery, Brain and Spinal Injury Center, University of California San Francisco and Zuckerberg San Francisco General Hospital, San Francisco, California
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307
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Nav1.1-Overexpressing Interneuron Transplants Restore Brain Rhythms and Cognition in a Mouse Model of Alzheimer's Disease. Neuron 2018; 98:75-89.e5. [PMID: 29551491 DOI: 10.1016/j.neuron.2018.02.029] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 01/12/2018] [Accepted: 02/26/2018] [Indexed: 01/01/2023]
Abstract
Inhibitory interneurons regulate the oscillatory rhythms and network synchrony that are required for cognitive functions and disrupted in Alzheimer's disease (AD). Network dysrhythmias in AD and multiple neuropsychiatric disorders are associated with hypofunction of Nav1.1, a voltage-gated sodium channel subunit predominantly expressed in interneurons. We show that Nav1.1-overexpressing, but not wild-type, interneuron transplants derived from the embryonic medial ganglionic eminence (MGE) enhance behavior-dependent gamma oscillatory activity, reduce network hypersynchrony, and improve cognitive functions in human amyloid precursor protein (hAPP)-transgenic mice, which simulate key aspects of AD. Increased Nav1.1 levels accelerated action potential kinetics of transplanted fast-spiking and non-fast-spiking interneurons. Nav1.1-deficient interneuron transplants were sufficient to cause behavioral abnormalities in wild-type mice. We conclude that the efficacy of interneuron transplantation and the function of transplanted cells in an AD-relevant context depend on their Nav1.1 levels. Disease-specific molecular optimization of cell transplants may be required to ensure therapeutic benefits in different conditions.
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308
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Alberti A, Thomas B, Marchal C. Spécificités de la prise en charge de l’épilepsie chez le sujet âgé. Presse Med 2018; 47:261-265. [DOI: 10.1016/j.lpm.2018.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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309
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Genome-wide profiling reveals functional diversification of ∆FosB gene targets in the hippocampus of an Alzheimer's disease mouse model. PLoS One 2018; 13:e0192508. [PMID: 29408867 PMCID: PMC5800686 DOI: 10.1371/journal.pone.0192508] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 01/24/2018] [Indexed: 01/20/2023] Open
Abstract
The activity-induced transcription factor ∆FosB has been implicated in Alzheimer’s disease (AD) as a critical regulator of hippocampal function and cognition downstream of seizures and network hyperexcitability. With its long half-life (> 1 week), ∆FosB is well-poised to modulate hippocampal gene expression over extended periods of time, enabling effects to persist even during seizure-free periods. However, the transcriptional mechanisms by which ∆FosB regulates hippocampal function are poorly understood due to lack of identified hippocampal gene targets. To identify putative ∆FosB gene targets, we employed high-throughput sequencing of genomic DNA bound to ∆FosB after chromatin immunoprecipitation (ChIP-sequencing). We compared ChIP-sequencing results from hippocampi of transgenic mice expressing mutant human amyloid precursor protein (APP) and nontransgenic (NTG) wild-type littermates. Surprisingly, only 52 ∆FosB gene targets were shared between NTG and APP mice; the vast majority of targets were unique to one genotype or the other. We also found a functional shift in the repertoire of ∆FosB gene targets between NTG and APP mice. A large number of targets in NTG mice are involved in neurodevelopment and/or cell morphogenesis, whereas in APP mice there is an enrichment of targets involved in regulation of membrane potential and neuronal excitability. RNA-sequencing and quantitative PCR experiments confirmed that expression of putative ∆FosB gene targets were altered in the hippocampus of APP mice. This study provides key insights into functional domains regulated by ∆FosB in the hippocampus, emphasizing remarkably different programs of gene regulation under physiological and pathological conditions.
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310
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Styr B, Slutsky I. Imbalance between firing homeostasis and synaptic plasticity drives early-phase Alzheimer's disease. Nat Neurosci 2018; 21:463-473. [PMID: 29403035 DOI: 10.1038/s41593-018-0080-x] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022]
Abstract
During recent years, the preclinical stage of Alzheimer's disease (AD) has become a major focus of research. Continued failures in clinical trials and the realization that early intervention may offer better therapeutic outcome triggered a conceptual shift from late-stage AD pathology to early-stage pathophysiology. While much effort has been directed at understanding the factors initiating AD, little is known about the principle basis underlying the disease progression at its early stages. In this Perspective, we suggest a hypothesis to explain the transition from 'silent' signatures of aberrant neural circuit activity to clinically evident memory impairments. Namely, we propose that failures in firing homeostasis and imbalance between firing stability and synaptic plasticity in cortico-hippocampal circuits represent the driving force of early disease progression. We analyze the main types of possible homeostatic failures and provide the essential conceptual framework for examining the causal link between dysregulation of firing homeostasis, aberrant neural circuit activity and memory-related plasticity impairments associated with early AD.
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Affiliation(s)
- Boaz Styr
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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311
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Intracellular Ca 2+ stores control in vivo neuronal hyperactivity in a mouse model of Alzheimer's disease. Proc Natl Acad Sci U S A 2018; 115:E1279-E1288. [PMID: 29358403 DOI: 10.1073/pnas.1714409115] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuronal hyperactivity is the emerging functional hallmark of Alzheimer's disease (AD) in both humans and different mouse models, mediating an impairment of memory and cognition. The mechanisms underlying neuronal hyperactivity remain, however, elusive. In vivo Ca2+ imaging of somatic, dendritic, and axonal activity patterns of cortical neurons revealed that both healthy aging and AD-related mutations augment neuronal hyperactivity. The AD-related enhancement occurred even without amyloid deposition and neuroinflammation, mainly due to presenilin-mediated dysfunction of intracellular Ca2+ stores in presynaptic boutons, likely causing more frequent activation of synaptic NMDA receptors. In mutant but not wild-type mice, store emptying reduced both the frequency and amplitude of presynaptic Ca2+ transients and, most importantly, normalized neuronal network activity. Postsynaptically, the store dysfunction was minor and largely restricted to hyperactive cells. These findings identify presynaptic Ca2+ stores as a key element controlling AD-related neuronal hyperactivity and as a target for disease-modifying treatments.
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312
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Jones AL, Britton JW, Blessing MM, Parisi JE, Cascino GD. Chronic traumatic encephalopathy in an epilepsy surgery cohort: Clinical and pathologic findings. Neurology 2018; 90:e474-e478. [PMID: 29321231 DOI: 10.1212/wnl.0000000000004927] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/27/2017] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine the occurrence of chronic traumatic encephalopathy (CTE) in young adult patients undergoing epilepsy surgery. METHODS Ten patients who underwent epilepsy surgery were randomly selected for this retrospective study. The patients were 18-45 years of age, had preoperative neuropsychological evaluation, and had 1 year postoperative follow-up. Microscopic sections from resections were evaluated for the presence of CTE with standard stains and antibodies to tau (clone AT8). RESULTS The median age at resection was 32.5 years (range 23-43) and the median duration of seizures was 23.5 years (range 3-28). Eight had a history of head injury. Preoperative neuropsychological testing showed mild to moderate cognitive impairment in 8 patients (80%). Pathologic examination in one patient showed focal sparse tau-immunoreactive lesions along descending rami and cortical gyral depths of the resected frontal lobe. Nine patients had no evidence of CTE. All focal cortical resections showed variable subpial and subcortical gliosis commonly identified in patients with chronic seizure disorders. CONCLUSIONS The present small retrospective observational study suggests that CTE may occur, but appears uncommon, in young adult patients undergoing surgical treatment for drug-resistant focal epilepsy. The significance of these findings requires further investigation to define the relative importance of tau accumulation in younger adult patients with drug-resistant focal epilepsy and cognitive decline.
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Affiliation(s)
- Amy L Jones
- From the Department of Neurology (A.L.J., J.W.B., J.E.P., G.D.C.), Division of Epilepsy (A.L.J., J.W.B., G.D.C.), and Department of Laboratory Medicine and Pathology (M.M.B., J.E.P.), Mayo Clinic, Rochester, MN
| | - Jeffrey W Britton
- From the Department of Neurology (A.L.J., J.W.B., J.E.P., G.D.C.), Division of Epilepsy (A.L.J., J.W.B., G.D.C.), and Department of Laboratory Medicine and Pathology (M.M.B., J.E.P.), Mayo Clinic, Rochester, MN
| | - Melissa M Blessing
- From the Department of Neurology (A.L.J., J.W.B., J.E.P., G.D.C.), Division of Epilepsy (A.L.J., J.W.B., G.D.C.), and Department of Laboratory Medicine and Pathology (M.M.B., J.E.P.), Mayo Clinic, Rochester, MN
| | - Joseph E Parisi
- From the Department of Neurology (A.L.J., J.W.B., J.E.P., G.D.C.), Division of Epilepsy (A.L.J., J.W.B., G.D.C.), and Department of Laboratory Medicine and Pathology (M.M.B., J.E.P.), Mayo Clinic, Rochester, MN
| | - Gregory D Cascino
- From the Department of Neurology (A.L.J., J.W.B., J.E.P., G.D.C.), Division of Epilepsy (A.L.J., J.W.B., G.D.C.), and Department of Laboratory Medicine and Pathology (M.M.B., J.E.P.), Mayo Clinic, Rochester, MN.
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313
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Scharfman HE, Kanner AM, Friedman A, Blümcke I, Crocker CE, Cendes F, Diaz-Arrastia R, Förstl H, Fenton AA, Grace AA, Palop J, Morrison J, Nehlig A, Prasad A, Wilcox KS, Jette N, Pohlmann-Eden B. Epilepsy as a Network Disorder (2): What can we learn from other network disorders such as dementia and schizophrenia, and what are the implications for translational research? Epilepsy Behav 2018; 78:302-312. [PMID: 29097123 PMCID: PMC5756681 DOI: 10.1016/j.yebeh.2017.09.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 12/18/2022]
Abstract
There is common agreement that many disorders of the central nervous system are 'complex', that is, there are many potential factors that influence the development of the disease, underlying mechanisms, and successful treatment. Most of these disorders, unfortunately, have no cure at the present time, and therapeutic strategies often have debilitating side effects. Interestingly, some of the 'complexities' of one disorder are found in another, and the similarities are often network defects. It seems likely that more discussions of these commonalities could advance our understanding and, therefore, have clinical implications or translational impact. With this in mind, the Fourth International Halifax Epilepsy Conference and Retreat was held as described in the prior paper, and this companion paper focuses on the second half of the meeting. Leaders in various subspecialties of epilepsy research were asked to address aging and dementia or psychosis in people with epilepsy (PWE). Commonalities between autism, depression, aging and dementia, psychosis, and epilepsy were the focus of the presentations and discussion. In the last session, additional experts commented on new conceptualization of translational epilepsy research efforts. Here, the presentations are reviewed, and salient points are highlighted.
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Affiliation(s)
- Helen E Scharfman
- Departments of Psychiatry, Neurosciences and Physiology, and the Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA.
| | - Andres M Kanner
- University of Miami, Miller School of Medicine, 1120 NW 14th Street, Room #1324, Miami, FL 33136, USA
| | - Alon Friedman
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada; Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ingmar Blümcke
- Neuropathological Institute, University Hospitals Erlangen, Germany
| | - Candice E Crocker
- Nova Scotia Early Psychosis Program, Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
| | - Fernando Cendes
- Department of Neurology, University of Campinas, 13083-888 Campinas, Sao Paulo, Brazil
| | - Ramon Diaz-Arrastia
- Centre for Neuroscience & Regenerative Medicine, Uniformed Services University of the Health Sciences, 12725 Twinbrook Parkway, Rockville, MD 20852, USA
| | - Hans Förstl
- Department of Psychiatry, University of Munich, Klinikum rechts der Isar, Ismaninger Strabe 22, D-81675 Munich, Germany
| | - André A Fenton
- Centre for Neural Science, New York University, 4 Washington Place, Room 809, New York, NY 10003, USA
| | - Anthony A Grace
- University of Pittsburgh, 456 Langley Hall, 4200 Fifth Avenue, Pittsburgh, PA 15269, USA
| | - Jorge Palop
- Department of Neurology, Gladstone Institute, 1650 Owens Street, San Francisco, CA 94158-2261, USA
| | - Jason Morrison
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
| | - Astrid Nehlig
- INSERM U 1129, Hôpital Necker, Paris, Faculty of Medicine, Strasbourg, France
| | - Asuri Prasad
- Department of Pediatrics, Children's Hospital of Western Ontario, London, ON, Canada
| | - Karen S Wilcox
- Department of Pharmacology & Toxicology, Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, USA
| | - Nathalie Jette
- Icahn School of Medicine at Mount Sinai, Department of Neurology, New York, NY, USA; Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Bernd Pohlmann-Eden
- Brain Repair Center, Life Science Research Institute, Dalhousie University, Room 229, PO Box 15000, Halifax, NS B3H4R2, Canada.
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314
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Epigenetic suppression of hippocampal calbindin-D28k by ΔFosB drives seizure-related cognitive deficits. Nat Med 2017; 23:1377-1383. [PMID: 29035369 PMCID: PMC5747956 DOI: 10.1038/nm.4413] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/29/2017] [Indexed: 12/13/2022]
Abstract
The calcium-binding protein calbindin-D28k is critical for hippocampal function and cognition1-3, but its expression is markedly decreased in various neurological disorders associated with epileptiform activity and seizures4-7. In Alzheimer's disease (AD) and epilepsy, both of which are accompanied by recurrent seizures8, the severity of cognitive deficits reflects the degree of calbindin reduction in the hippocampal dentate gyrus (DG)4,9,10. However, despite the importance of calbindin in both neuronal physiology and pathology, the regulatory mechanisms that control its expression in the hippocampus are poorly understood. Here we report an epigenetic mechanism by which seizures chronically suppress hippocampal calbindin expression and impair cognition. We demonstrate that ΔFosB, a highly stable transcription factor, is induced in the hippocampus of mouse models of AD and seizures, where it binds and triggers histone deacetylation at the calbindin gene (Calb1) promoter, and downregulates Calb1 transcription. Notably, increasing DG calbindin levels, either by direct virus-mediated expression or inhibition of ΔFosB signaling, improves spatial memory in a mouse model of AD. Moreover, levels of ΔFosB and calbindin expression are inversely related in DG of patients with temporal lobe epilepsy (TLE) or AD, and correlate with performance on the Mini-Mental State Examination (MMSE). We propose that chronic suppression of calbindin by ΔFosB is one mechanism by which intermittent seizures drive persistent cognitive deficits in conditions accompanied by recurrent seizures.
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315
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Ranasinghe KG, Hinkley LB, Beagle AJ, Mizuiri D, Honma SM, Welch AE, Hubbard I, Mandelli ML, Miller ZA, Garrett C, La A, Boxer AL, Houde JF, Miller BL, Vossel KA, Gorno-Tempini ML, Nagarajan SS. Distinct spatiotemporal patterns of neuronal functional connectivity in primary progressive aphasia variants. Brain 2017; 140:2737-2751. [PMID: 28969381 DOI: 10.1093/brain/awx217] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 07/04/2017] [Indexed: 12/15/2022] Open
Abstract
Primary progressive aphasia is a syndrome characterized by progressive loss of language abilities with three main phenotypic clinical presentations, including logopenic, non-fluent/agrammatic, and semantic variants. Previous imaging studies have shown unique anatomic impacts within language networks in each variant. However, direct measures of spontaneous neuronal activity and functional integrity of these impacted neural networks in primary progressive aphasia are lacking. The aim of this study was to characterize the spatial and temporal patterns of resting state neuronal synchronizations in primary progressive aphasia syndromes. We hypothesized that resting state brain oscillations will show unique deficits within language network in each variant of primary progressive aphasia. We examined 39 patients with primary progressive aphasia including logopenic variant (n = 14, age = 61 ± 9 years), non-fluent/agrammatic variant (n = 12, age = 71 ± 8 years) and semantic variant (n = 13, age = 65 ± 7 years) using magnetoencephalographic imaging, compared to a control group that was matched in age and gender to each primary progressive aphasia subgroup (n = 20, age = 65 ± 5 years). Each patient underwent a complete clinical evaluation including a comprehensive battery of language tests. We examined the whole-brain resting state functional connectivity as measured by imaginary coherence in each patient group compared to the control cohort, in three frequency oscillation bands-delta-theta (2-8 Hz); alpha (8-12 Hz); beta (12-30 Hz). Each variant showed a distinct spatiotemporal pattern of altered functional connectivity compared to age-matched controls. Specifically, we found significant hyposynchrony of alpha and beta frequency within the left posterior temporal and occipital cortices in patients with the logopenic variant, within the left inferior frontal cortex in patients with the non-fluent/agrammatic variant, and within the left temporo-parietal junction in patients with the semantic variant. Patients with logopenic variant primary progressive aphasia also showed significant hypersynchrony of delta-theta frequency within bilateral medial frontal and posterior parietal cortices. Furthermore, region of interest-based analyses comparing the spatiotemporal patterns of variant-specific regions of interest identified in comparison to age-matched controls showed significant differences between primary progressive aphasia variants themselves. We also found distinct patterns of regional spectral power changes in each primary progressive aphasia variant, compared to age-matched controls. Our results demonstrate neurophysiological signatures of network-specific neuronal dysfunction in primary progressive aphasia variants. The unique spatiotemporal patterns of neuronal synchrony signify diverse neurophysiological disruptions and pathological underpinnings of the language network in each variant.
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Affiliation(s)
- Kamalini G Ranasinghe
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Leighton B Hinkley
- Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco CA 94143, USA
| | - Alexander J Beagle
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Danielle Mizuiri
- Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco CA 94143, USA
| | - Susanne M Honma
- Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco CA 94143, USA
| | - Ariane E Welch
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Isabel Hubbard
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Maria Luisa Mandelli
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Zachary A Miller
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Coleman Garrett
- Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco CA 94143, USA
| | - Alice La
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Adam L Boxer
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - John F Houde
- Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco CA 94143, USA.,Speech Neuroscience Laboratory, Department of Otolaryngology, Head and Neck Surgery, University of California San Francisco, San Francisco CA 94143, USA
| | - Bruce L Miller
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Keith A Vossel
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Maria Luisa Gorno-Tempini
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Srikantan S Nagarajan
- Biomagnetic Imaging Laboratory, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco CA 94143, USA.,Speech Neuroscience Laboratory, Department of Otolaryngology, Head and Neck Surgery, University of California San Francisco, San Francisco CA 94143, USA
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316
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Corticothalamic network dysfunction and Alzheimer's disease. Brain Res 2017; 1702:38-45. [PMID: 28919464 DOI: 10.1016/j.brainres.2017.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/11/2017] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease that is characterized by progressive cognitive decline and a prominent loss of hippocampal-dependent memory. Therefore, much focus has been placed on understanding the function and dysfunction of the hippocampus in AD. However, AD is also accompanied by a number of other debilitating cognitive and behavioral alterations including deficits in attention, cognitive processing, and sleep maintenance. The underlying mechanisms that give rise to impairments in such diverse behavioral domains are unknown, and identifying them would shed insight into the multifactorial nature of AD as well as reveal potential new therapeutic targets to improve overall function in AD. We present here several lines of evidence that suggest that dysregulation of the corticothalamic network may be a common denominator that contributes to the diverse cognitive and behavioral alterations in AD. First, we will review the mechanisms by which this network regulates processes that include attention, cognitive processing, learning and memory, and sleep maintenance. Then we will review how these behavioral and cognitive domains are altered in AD. We will also discuss how dysregulation of tightly regulated activity in the corticothalamic network can give rise to non-convulsive seizures and other forms of epileptiform activity that have also been documented in both AD patients and transgenic mouse models of AD. In summary, the corticothalamic network has the potential to be a master regulator of diverse cognitive and behavioral domains that are affected in AD.
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317
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Horváth A, Szűcs A, Barcs G, Fabó D, Kelemen A, Halász P, Erőss L, Kamondi A. Interictal Epileptiform Activity in the Foramen Ovale Electrodes of a Frontotemporal Dementia Patient. J Alzheimers Dis Rep 2017; 1:89-96. [PMID: 30480231 PMCID: PMC6159658 DOI: 10.3233/adr-170020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Frontotemporal dementia (FTD) is a frequent cause of cognitive decline. While epilepsy is an important comorbidity of Alzheimer’s disease, we lack studies on its presence in FTD. We report on an FTD patient with transient, short-term changes of behavior and cognitive performance suggesting non-convulsive epilepsy. Video-EEG recording with foramen ovale (FO) electrodes revealed mesio-temporal epileptiform potentials, undetectable by scalp leads. We also found beta spindles in the FO electrodes, not described in the literature. We conclude that video-EEG monitoring with FO electrodes might usefully complement the assessment of dementia-associated epilepsy opening new perspectives in dementia-research.
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Affiliation(s)
- András Horváth
- National Institute of Clinical Neurosciences, Budapest, Hungary.,Semmelweis University School of PhD Studies, János Szentágothai Doctoral School of Neurosciences, Budapest, Hungary.,Department of Anatomy Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Anna Szűcs
- National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Gábor Barcs
- National Institute of Clinical Neurosciences, Budapest, Hungary.,Semmelweis University School of PhD Studies, János Szentágothai Doctoral School of Neurosciences, Budapest, Hungary
| | - Dániel Fabó
- National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Anna Kelemen
- National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Péter Halász
- National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Loránd Erőss
- National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Anita Kamondi
- National Institute of Clinical Neurosciences, Budapest, Hungary.,Department of Neurology, Semmelweis University, Budapest, Hungary
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318
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Burke JF, Peters A, Rolston JD. Intracranial Electroencephalography for Alzheimer's. Neurosurgery 2017; 81:N23-N24. [PMID: 28859460 DOI: 10.1093/neuros/nyx397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- John F Burke
- Department of Neurological Surgery University of California San Francisco San Francisco, California
| | - Angela Peters
- Department of Neurology University of Utah Salt Lake City, Utah
| | - John D Rolston
- Department of Neurosurgery University of Utah Salt Lake City, Utah
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319
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Sarkis RA, Willment KC, Gale SA, Dworetzky BA. Recurrent Epileptic Auras As a Presenting Symptom of Alzheimer's Disease. Front Neurol 2017; 8:360. [PMID: 28790971 PMCID: PMC5522840 DOI: 10.3389/fneur.2017.00360] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/07/2017] [Indexed: 11/13/2022] Open
Abstract
Seizures are a common co-morbidity during the course of Alzheimer's disease (AD) and in a subset of patients may be one of the presenting symptoms. In this case series, we highlight three patients with recurrent medically refractory epileptic auras whose work up ultimately lead to the diagnosis of AD. All three patients underwent prolonged EEG, serial neuropsychological testing, FDG-PET, cerebrospinal fluid (CSF) AD biomarkers, and MRI. CSF biomarkers were particularly helpful in two cases. These cases highlight the importance of having a high index of suspicion for AD in new onset "idiopathic" epilepsy in the elderly.
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Affiliation(s)
- Rani A Sarkis
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Kim C Willment
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Seth A Gale
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Barbara A Dworetzky
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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320
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Itzhaki RF. Herpes simplex virus type 1 and Alzheimer's disease: possible mechanisms and signposts. FASEB J 2017; 31:3216-3226. [DOI: 10.1096/fj.201700360] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 04/21/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Ruth F. Itzhaki
- Nuffield Department of Clinical NeurosciencesUniversity of Oxford Oxford United Kingdom
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321
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Haberman RP, Branch A, Gallagher M. Targeting Neural Hyperactivity as a Treatment to Stem Progression of Late-Onset Alzheimer's Disease. Neurotherapeutics 2017; 14:662-676. [PMID: 28560709 PMCID: PMC5509635 DOI: 10.1007/s13311-017-0541-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sporadic late-onset Alzheimer's disease (LOAD), the most common form of dementia in the elderly, causes progressive and severe loss of cognitive abilities. With greater numbers of people living to advanced ages, LOAD will increasingly burden both the healthcare system and society. There are currently no available disease-modifying therapies, and the failure of several recent pathology-based strategies has highlighted the urgent need for effective therapeutic targets. With aging as the greatest risk factor for LOAD, targeting mechanisms by which aging contributes to disease could prove an effective strategy to delay progression to clinical dementia by intervention in elderly individuals in an early prodromal stage of disease. Excess neural activity in the hippocampus, a recently described phenomenon associated with age-dependent memory loss, was first identified in animal models of aging and subsequently translated to clinical conditions of aging and early-stage LOAD. Critically, elevated activity was similarly localized to specific circuits within the hippocampal formation in aged animals and humans. Here we review evidence for hippocampal hyperactivity as a significant contributor to age-dependent cognitive decline and the progressive accumulation of pathology in LOAD. We also describe studies demonstrating the efficacy of reducing hyperactivity with an initial test therapy, levetiracetam (Keppra), an atypical antiepileptic. By targeting excess neural activity, levetiracetam may improve cognition and attenuate the accumulation of pathology contributing to progression to the dementia phase of LOAD.
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Affiliation(s)
- Rebecca P Haberman
- Department of Psychological and Brain Sciences, The Johns Hopkins University, 3400 North Charles Street, 116 Dunning Hall, Baltimore, MD, 21218, USA.
| | - Audrey Branch
- Department of Psychological and Brain Sciences, The Johns Hopkins University, 3400 North Charles Street, 116 Dunning Hall, Baltimore, MD, 21218, USA
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, The Johns Hopkins University, 3400 North Charles Street, 116 Dunning Hall, Baltimore, MD, 21218, USA
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322
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Vossel KA, Tartaglia MC, Nygaard HB, Zeman AZ, Miller BL. Epileptic activity in Alzheimer's disease: causes and clinical relevance. Lancet Neurol 2017; 16:311-322. [PMID: 28327340 DOI: 10.1016/s1474-4422(17)30044-3] [Citation(s) in RCA: 345] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/10/2017] [Accepted: 01/31/2017] [Indexed: 01/18/2023]
Abstract
Epileptic activity is frequently associated with Alzheimer's disease; this association has therapeutic implications, because epileptic activity can occur at early disease stages and might contribute to pathogenesis. In clinical practice, seizures in patients with Alzheimer's disease can easily go unrecognised because they usually present as non-motor seizures, and can overlap with other symptoms of the disease. In patients with Alzheimer's disease, seizures can hasten cognitive decline, highlighting the clinical relevance of early recognition and treatment. Some evidence indicates that subclinical epileptiform activity in patients with Alzheimer's disease, detected by extended neurophysiological monitoring, can also lead to accelerated cognitive decline. Treatment of clinical seizures in patients with Alzheimer's disease with select antiepileptic drugs (AEDs), in low doses, is usually well tolerated and efficacious. Moreover, studies in mouse models of Alzheimer's disease suggest that certain classes of AEDs that reduce network hyperexcitability have disease-modifying properties. These AEDs target mechanisms of epileptogenesis involving amyloid β and tau. Clinical trials targeting network hyperexcitability in patients with Alzheimer's disease will identify whether AEDs or related strategies could improve their cognitive symptoms or slow decline.
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Affiliation(s)
- Keith A Vossel
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA.
| | | | - Haakon B Nygaard
- Division of Neurology, University of British Columbia, Vancouver, BC, Canada
| | - Adam Z Zeman
- Cognitive Neurology Research Group, University of Exeter Medical School, Exeter, UK
| | - Bruce L Miller
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA
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323
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Cretin B, Philippi N, Bousiges O, Dibitonto L, Sellal F, Martin-Hunyadi C, Blanc F. Do we know how to diagnose epilepsy early in Alzheimer's disease? Rev Neurol (Paris) 2017; 173:374-380. [DOI: 10.1016/j.neurol.2017.03.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 01/04/2017] [Accepted: 03/31/2017] [Indexed: 10/19/2022]
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324
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Calcineurin/NFAT Signaling in Activated Astrocytes Drives Network Hyperexcitability in Aβ-Bearing Mice. J Neurosci 2017; 37:6132-6148. [PMID: 28559377 DOI: 10.1523/jneurosci.0877-17.2017] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 12/25/2022] Open
Abstract
Hyperexcitable neuronal networks are mechanistically linked to the pathologic and clinical features of Alzheimer's disease (AD). Astrocytes are a primary defense against hyperexcitability, but their functional phenotype during AD is poorly understood. Here, we found that activated astrocytes in the 5xFAD mouse model were strongly associated with proteolysis of the protein phosphatase calcineurin (CN) and the elevated expression of the CN-dependent transcription factor nuclear factor of activated T cells 4 (NFAT4). Intrahippocampal injections of adeno-associated virus vectors containing the astrocyte-specific promoter Gfa2 and the NFAT inhibitory peptide VIVIT reduced signs of glutamate-mediated hyperexcitability in 5xFAD mice, measured in vivo with microelectrode arrays and ex vivo brain slices, using whole-cell voltage clamp. VIVIT treatment in 5xFAD mice led to increased expression of the astrocytic glutamate transporter GLT-1 and to attenuated changes in dendrite morphology, synaptic strength, and NMDAR-dependent responses. The results reveal astrocytic CN/NFAT4 as a key pathologic mechanism for driving glutamate dysregulation and neuronal hyperactivity during AD.SIGNIFICANCE STATEMENT Neuronal hyperexcitability and excitotoxicity are increasingly recognized as important mechanisms for neurodegeneration and dementia associated with Alzheimer's disease (AD). Astrocytes are profoundly activated during AD and may lose their capacity to regulate excitotoxic glutamate levels. Here, we show that a highly active calcineurin (CN) phosphatase fragment and its substrate transcription factor, nuclear factor of activated T cells (NFAT4), appear in astrocytes in direct proportion to the extent of astrocyte activation. The blockade of astrocytic CN/NFAT signaling in a common mouse model of AD, using adeno-associated virus vectors normalized glutamate signaling dynamics, increased astrocytic glutamate transporter levels and alleviated multiple signs of neuronal hyperexcitability. The results suggest that astrocyte activation drives hyperexcitability during AD through a mechanism involving aberrant CN/NFAT signaling and impaired glutamate transport.
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325
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Zilberter Y, Zilberter M. The vicious circle of hypometabolism in neurodegenerative diseases: Ways and mechanisms of metabolic correction. J Neurosci Res 2017; 95:2217-2235. [PMID: 28463438 DOI: 10.1002/jnr.24064] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 12/13/2022]
Abstract
Hypometabolism, characterized by decreased brain glucose consumption, is a common feature of many neurodegenerative diseases. Initial hypometabolic brain state, created by characteristic risk factors, may predispose the brain to acquired epilepsy and sporadic Alzheimer's and Parkinson's diseases, which are the focus of this review. Analysis of available data suggests that deficient glucose metabolism is likely a primary initiating factor for these diseases, and that resulting neuronal dysfunction further promotes the metabolic imbalance, establishing an effective positive feedback loop and a downward spiral of disease progression. Therefore, metabolic correction leading to the normalization of abnormalities in glucose metabolism may be an efficient tool to treat the neurological disorders by counteracting their primary pathological mechanisms. Published and preliminary experimental results on this approach for treating Alzheimer's disease and epilepsy models support the efficacy of metabolic correction, confirming the highly promising nature of the strategy. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yuri Zilberter
- Aix-Marseille Université, INSERM UMR1106, Institut de Neurosciences des Systèmes, Marseille, France
| | - Misha Zilberter
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California, 94158, USA
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326
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Lam AD, Deck G, Goldman A, Eskandar EN, Noebels J, Cole AJ. Silent hippocampal seizures and spikes identified by foramen ovale electrodes in Alzheimer's disease. Nat Med 2017; 23:678-680. [PMID: 28459436 PMCID: PMC5461182 DOI: 10.1038/nm.4330] [Citation(s) in RCA: 245] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/17/2017] [Indexed: 01/08/2023]
Abstract
We directly assessed mesial temporal activity in two Alzheimer’s disease (AD) patients without a history or EEG evidence of seizures, using intracranial foramen ovale electrodes. We detected clinically silent hippocampal seizures and epileptiform spikes during sleep, a period when both were most likely to interfere with memory consolidation. These index cases support a model in which early development of occult hippocampal hyperexcitability may contribute to the pathogenesis of AD.
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Affiliation(s)
- Alice D Lam
- MGH Epilepsy Service, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Gina Deck
- MGH Epilepsy Service, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Alica Goldman
- Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
| | - Emad N Eskandar
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey Noebels
- Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
| | - Andrew J Cole
- MGH Epilepsy Service, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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327
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Tjong E, McHugh W, Peng Y. Reversible dementia: subclinical seizure in early-onset dementia. Clin Case Rep 2017; 5:321-327. [PMID: 28265399 PMCID: PMC5331190 DOI: 10.1002/ccr3.843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 12/20/2016] [Accepted: 01/06/2017] [Indexed: 01/08/2023] Open
Abstract
We report a case of early‐onset dementia with subclinical seizures. Aggressive seizure control improved the patient's cognition. Commonly, an EEG is only performed following overt behavioral seizures. Therefore, subclinical seizures tend to be underdiagnosed. Serial or extended EEG should be seriously considered in patients with early‐onset dementia.
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Affiliation(s)
- Elysia Tjong
- Department of NeurologyRenown Institute for Neurosciences, Renown HealthUniversity of NevadaRenoNevadaUSA
| | - William McHugh
- Department of NeurologyRenown Institute for Neurosciences, Renown HealthUniversity of NevadaRenoNevadaUSA
| | - Yen‐Yi Peng
- Department of NeurologyRenown Institute for Neurosciences, Renown HealthUniversity of NevadaRenoNevadaUSA
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328
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Husain M. Alzheimer's disease: time to focus on the brain, not just molecules. Brain 2017; 140:251-253. [DOI: 10.1093/brain/aww353] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 01/01/2023] Open
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329
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Palop JJ, Mucke L. Network abnormalities and interneuron dysfunction in Alzheimer disease. Nat Rev Neurosci 2016; 17:777-792. [PMID: 27829687 DOI: 10.1038/nrn.2016.141] [Citation(s) in RCA: 603] [Impact Index Per Article: 75.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The function of neural circuits and networks can be controlled, in part, by modulating the synchrony of their components' activities. Network hypersynchrony and altered oscillatory rhythmic activity may contribute to cognitive abnormalities in Alzheimer disease (AD). In this condition, network activities that support cognition are altered decades before clinical disease onset, and these alterations predict future pathology and brain atrophy. Although the precise causes and pathophysiological consequences of these network alterations remain to be defined, interneuron dysfunction and network abnormalities have emerged as potential mechanisms of cognitive dysfunction in AD and related disorders. Here, we explore the concept that modulating these mechanisms may help to improve brain function in these conditions.
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Affiliation(s)
- Jorge J Palop
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, USA.,Department of Neurology, University of California, San Francisco, 1650 Owens Street, San Francisco, California 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, USA.,Department of Neurology, University of California, San Francisco, 1650 Owens Street, San Francisco, California 94158, USA
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