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Buchanan RA, Wang Y, May JM, Harrison FE. Ascorbate insufficiency disrupts glutamatergic signaling and alters electroencephalogram phenotypes in a mouse model of Alzheimer's disease. Neurobiol Dis 2024; 199:106602. [PMID: 39004234 DOI: 10.1016/j.nbd.2024.106602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/16/2024] Open
Abstract
Clinical studies have reported that increased epileptiform and subclinical epileptiform activity can be detected in many patients with an Alzheimer's disease (AD) diagnosis using electroencephalogram (EEG) and this may correlate with poorer cognition. Ascorbate may have a specific role as a neuromodulator in AD as it is released concomitantly with glutamate reuptake following excitatory neurotransmission. Insufficiency may therefore result in an exacerbated excitatory/inhibitory imbalance in neuronal signaling. Using a mouse model of AD that requires dietary ascorbate (Gulo-/-APPswe/PSEN1dE9), EEG was recorded at baseline and during 4 weeks of ascorbate depletion in young (5-month-old) and aged (20-month-old) animals. Data were scored for changes in quantity of spike trains, individual spikes, sleep-wake rhythms, sleep fragmentation, and brainwave power bands during light periods each week. We found an early increase in neuronal spike discharges with age and following ascorbate depletion in AD model mice and not controls, which did not correlate with brain amyloid load. Our data also show more sleep fragmentation with age and with ascorbate depletion. Additionally, changes in brain wave activity were observed within different vigilance states in both young and aged mice, where Gulo-/-APPswe/PSEN1dE9 mice had shifts towards higher frequency bands (alpha, beta, and gamma) and ascorbate depletion resulted in shifts towards lower frequency bands (delta and theta). Microarray data supported ascorbate insufficiency altering glutamatergic transmission through the decreased expression of glutamate related genes, however no changes in protein expression of glutamate reuptake transporters were observed. These data suggest that maintaining optimal brain ascorbate levels may support normal brain electrical activity and sleep patterns, particularly in AD patient populations where disruptions are observed.
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Affiliation(s)
- Rebecca A Buchanan
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
| | - Yuhan Wang
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - James M May
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Fiona E Harrison
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.
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Kalyvas AC, Dimitriou M, Ioannidis P, Grigoriadis N, Afrantou T. Alzheimer's Disease and Epilepsy: Exploring Shared Pathways and Promising Biomarkers for Future Treatments. J Clin Med 2024; 13:3879. [PMID: 38999445 PMCID: PMC11242231 DOI: 10.3390/jcm13133879] [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: 05/07/2024] [Revised: 06/25/2024] [Accepted: 06/29/2024] [Indexed: 07/14/2024] Open
Abstract
Background: Alzheimer's disease (AD) and epilepsy represent two complex neurological disorders with distinct clinical manifestations, yet recent research has highlighted their intricate interplay. This review examines the association between AD and epilepsy, with particular emphasis on late-onset epilepsy of unknown etiology, increasingly acknowledged as a prodrome of AD. It delves into epidemiology, pathogenic mechanisms, clinical features, diagnostic characteristics, treatment strategies, and emerging biomarkers to provide a comprehensive understanding of this relationship. Methods: A comprehensive literature search was conducted, identifying 128 relevant articles published between 2018 and 2024. Results: Findings underscore a bidirectional relationship between AD and epilepsy, indicating shared pathogenic pathways that extend beyond traditional amyloid-beta and Tau protein pathology. These pathways encompass neuroinflammation, synaptic dysfunction, structural and network alterations, as well as molecular mechanisms. Notably, epileptic activity in AD patients may exacerbate cognitive decline, necessitating prompt detection and treatment. Novel biomarkers, such as subclinical epileptiform activity detected via advanced electroencephalographic techniques, offer promise for early diagnosis and targeted interventions. Furthermore, emerging therapeutic approaches targeting shared pathogenic mechanisms hold potential for disease modification in both AD and epilepsy. Conclusions: This review highlights the importance of understanding the relationship between AD and epilepsy, providing insights into future research directions. Clinical data and diagnostic methods are also reviewed, enabling clinicians to implement more effective treatment strategies.
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Affiliation(s)
- Athanasios-Christos Kalyvas
- 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, GR54636 Thessaloniki, Greece
| | - Maria Dimitriou
- 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, GR54636 Thessaloniki, Greece
| | - Panagiotis Ioannidis
- 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, GR54636 Thessaloniki, Greece
| | - Nikolaos Grigoriadis
- 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, GR54636 Thessaloniki, Greece
| | - Theodora Afrantou
- 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, GR54636 Thessaloniki, Greece
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Nicolas G. Lessons from genetic studies in Alzheimer disease. Rev Neurol (Paris) 2024; 180:368-377. [PMID: 38429159 DOI: 10.1016/j.neurol.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 12/27/2023] [Indexed: 03/03/2024]
Abstract
Research on Alzheimer disease (AD) genetics has provided critical advances to the knowledge of AD pathophysiological mechanisms. The etiology of AD can be divided into monogenic (autosomal dominant inheritance) and complex (multifactorial determinism). In monogenic AD, recent advances mainly concern mutation-associated mechanisms, presymptomatic clinical studies, and the search for modifiers of ages of onset that are still ongoing. In complex AD, genetic factors can be further categorized into three classes: (i) the APOE-ɛ4 and ɛ2 common alleles that represent a category by themselves as they are both common and with a strong impact on AD risk; (ii) common variants with a modest effect, identified in genome-wide association studies (GWAS); and (iii) rare variants with a moderate-to-strong effect, identified in case-control sequencing studies. Regarding APOE, odds ratios, available in multiple ethnicities, can now be converted into penetrance curves, although such curves remain to be performed in diverse ethnicities. In addition, advances in the understanding of mechanisms have been recently reported and rare APOE variants add to the complexity. In the GWAS category, novel loci have been discovered thanks to larger studies, doubling the number of hits as compared to the previous reference meta-analysis. However, such modest risk factors cannot be used in the clinic, neither individually, nor in genetic risk scores. In the category of rare variants, two novel genes, ABCA1 and ATP8B4 now add to the three main ones, TREM2, SORL1, and ABCA7. The study of such rare variants suggests oligogenic inheritance in some families, as also suggested by digenic penetrance curves for SORL1 loss-of-function variants with APOE-ɛ4. Cumulate frequencies of definite (so-called) rare risk factors are 2.3% to 3.6% (depending on thresholds on odds ratios) in control databases and many more remain to be classified and identified, showing how important these risk factors may be as part of the complex determinism of AD. A better understanding of these rare risk factors and their combined effects on each other, with common variants, and with environmental factors, should allow for a prediction of AD risk and, eventually, preventive medicine. Taken together, most genetic determinants of AD, in monogenic and in complex forms, point toward the aggregation of Aβ as a pivotal triggering factor, such that targeting it may be efficient as prevention in at-risk individuals. The role of neuroinflammation, microglia, and Tau pathology modulation are important sources of research for disease modification.
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Affiliation(s)
- G Nicolas
- Univ Rouen Normandie, Normandie Univ, Inserm U1245 and CHU Rouen, Department of Genetics and CNRMAJ, 76000 Rouen, France.
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Nicolas G. Recent advances in Alzheimer disease genetics. Curr Opin Neurol 2024; 37:154-165. [PMID: 38235704 DOI: 10.1097/wco.0000000000001242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
PURPOSE OF REVIEW Genetics studies provide important insights into Alzheimer disease (AD) etiology and mechanisms. Critical advances have been made recently, mainly thanks to the access to novel techniques and larger studies. RECENT FINDINGS In monogenic AD, progress has been made with a better understanding of the mechanisms associated with pathogenic variants and the input of clinical studies in presymptomatic individuals. In complex AD, increasing sample sizes in both DNA chip-based (genome-wide association studies, GWAS) and exome/genome sequencing case-control studies unveiled novel common and rare risk factors, while the understanding of their combined effect starts to suggest the existence of rare families with oligogenic inheritance of early-onset, nonmonogenic, AD. SUMMARY Most genetic risk factors with a known consequence designate the aggregation of the Aβ peptide as a core etiological factor in complex AD thus confirming that the research based on monogenic AD - where the amyloid cascade seems more straightforward - is relevant to complex AD as well. Novel mechanistic insights and risk factor studies unveiling novel factors and attempting to combine the effect of common and rare variants will offer promising perspectives for future AD prevention, at least regarding early-onset AD, and probably in case of later onset as well.
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Affiliation(s)
- Gaël Nicolas
- Univ Rouen Normandie, Normandie Univ, Inserm U1245 and CHU Rouen, Department of Genetics and CNRMAJ, F-76000 Rouen, France
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Lisgaras CP, Scharfman HE. Interictal spikes in Alzheimer's disease: Preclinical evidence for dominance of the dentate gyrus and cholinergic control by the medial septum. Neurobiol Dis 2023; 187:106294. [PMID: 37714307 PMCID: PMC10617404 DOI: 10.1016/j.nbd.2023.106294] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/17/2023] Open
Abstract
Interictal spikes (IIS) are a common type of abnormal electrical activity in Alzheimer's disease (AD) and preclinical models. The brain regions where IIS are largest are not known but are important because such data would suggest sites that contribute to IIS generation. Because hippocampus and cortex exhibit altered excitability in AD models, we asked which areas dominate the activity during IIS along the cortical-CA1-dentate gyrus (DG) dorso-ventral axis. Because medial septal (MS) cholinergic neurons are overactive when IIS typically occur, we also tested the novel hypothesis that silencing the MS cholinergic neurons selectively would reduce IIS. We used mice that simulate aspects of AD: Tg2576 mice, presenilin 2 (PS2) knockout mice and Ts65Dn mice. To selectively silence MS cholinergic neurons, Tg2576 mice were bred with choline-acetyltransferase (ChAT)-Cre mice and offspring were injected in the MS with AAV encoding inhibitory designer receptors exclusively activated by designer drugs (DREADDs). We recorded local field potentials along the cortical-CA1-DG axis using silicon probes during wakefulness, slow-wave sleep (SWS) and rapid eye movement (REM) sleep. We detected IIS in all transgenic or knockout mice but not age-matched controls. IIS were detectable throughout the cortical-CA1-DG axis and occurred primarily during REM sleep. In all 3 mouse lines, IIS amplitudes were significantly greater in the DG granule cell layer vs. CA1 pyramidal layer or overlying cortex. Current source density analysis showed robust and early current sources in the DG, and additional sources in CA1 and the cortex also. Selective chemogenetic silencing of MS cholinergic neurons significantly reduced IIS rate during REM sleep without affecting the overall duration, number of REM bouts, latency to REM sleep, or theta power during REM. Notably, two control interventions showed no effects. Consistent maximal amplitude and strong current sources of IIS in the DG suggest that the DG is remarkably active during IIS. In addition, selectively reducing MS cholinergic tone, at times when MS is hyperactive, could be a new strategy to reduce IIS in AD.
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Affiliation(s)
- Christos Panagiotis Lisgaras
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, and the Neuroscience Institute New York University Langone Health, 550 First Ave., New York, NY 10016, United States of America; Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, New York State Office of Mental Health, 140 Old Orangeburg Road, Bldg. 35, Orangeburg, NY 10962, United States of America.
| | - Helen E Scharfman
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, and the Neuroscience Institute New York University Langone Health, 550 First Ave., New York, NY 10016, United States of America; Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, New York State Office of Mental Health, 140 Old Orangeburg Road, Bldg. 35, Orangeburg, NY 10962, United States of America
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Leitner DF, Kanshin E, Faustin A, Thierry M, Friedman D, Devore S, Ueberheide B, Devinsky O, Wisniewski T. Localized proteomic differences in the choroid plexus of Alzheimer's disease and epilepsy patients. Front Neurol 2023; 14:1221775. [PMID: 37521285 PMCID: PMC10379643 DOI: 10.3389/fneur.2023.1221775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/22/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction Alzheimer's disease (AD) and epilepsy are reciprocally related. Among sporadic AD patients, clinical seizures occur in 10-22% and subclinical epileptiform abnormalities occur in 22-54%. Cognitive deficits, especially short-term memory impairments, occur in most epilepsy patients. Common neurophysiological and molecular mechanisms occur in AD and epilepsy. The choroid plexus undergoes pathological changes in aging, AD, and epilepsy, including decreased CSF turnover, amyloid beta (Aβ), and tau accumulation due to impaired clearance and disrupted CSF amino acid homeostasis. This pathology may contribute to synaptic dysfunction in AD and epilepsy. Methods We evaluated control (n = 8), severe AD (n = 8; A3, B3, C3 neuropathology), and epilepsy autopsy cases (n = 12) using laser capture microdissection (LCM) followed by label-free quantitative mass spectrometry on the choroid plexus adjacent to the hippocampus at the lateral geniculate nucleus level. Results Proteomics identified 2,459 proteins in the choroid plexus. At a 5% false discovery rate (FDR), 616 proteins were differentially expressed in AD vs. control, 1 protein in epilepsy vs. control, and 438 proteins in AD vs. epilepsy. There was more variability in the epilepsy group across syndromes. The top 20 signaling pathways associated with differentially expressed proteins in AD vs. control included cell metabolism pathways; activated fatty acid beta-oxidation (p = 2.00 x 10-7, z = 3.00), and inhibited glycolysis (p = 1.00 x 10-12, z = -3.46). For AD vs. epilepsy, the altered pathways included cell metabolism pathways, activated complement system (p = 5.62 x 10-5, z = 2.00), and pathogen-induced cytokine storm (p = 2.19 x 10-2, z = 3.61). Of the 617 altered proteins in AD and epilepsy vs. controls, 497 (81%) were positively correlated (p < 0.0001, R2 = 0.27). Discussion We found altered signaling pathways in the choroid plexus of severe AD cases and many correlated changes in the protein expression of cell metabolism pathways in AD and epilepsy cases. The shared molecular mechanisms should be investigated further to distinguish primary pathogenic changes from the secondary ones. These mechanisms could inform novel therapeutic strategies to prevent disease progression or restore normal function. A focus on dual-diagnosed AD/epilepsy cases, specific epilepsy syndromes, such as temporal lobe epilepsy, and changes across different severity levels in AD and epilepsy would add to our understanding.
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Affiliation(s)
- Dominique F. Leitner
- Comprehensive Epilepsy Center, New York University Grossman School of Medicine, New York, NY, United States
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Evgeny Kanshin
- Proteomics Laboratory, Division of Advanced Research Technologies, New York University Grossman School of Medicine, New York, NY, United States
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, United States
| | - Arline Faustin
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, United States
| | - Manon Thierry
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Daniel Friedman
- Comprehensive Epilepsy Center, New York University Grossman School of Medicine, New York, NY, United States
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Sasha Devore
- Comprehensive Epilepsy Center, New York University Grossman School of Medicine, New York, NY, United States
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Beatrix Ueberheide
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Proteomics Laboratory, Division of Advanced Research Technologies, New York University Grossman School of Medicine, New York, NY, United States
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, United States
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, New York University Grossman School of Medicine, New York, NY, United States
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Thomas Wisniewski
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, United States
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Melgosa-Ecenarro L, Doostdar N, Radulescu CI, Jackson JS, Barnes SJ. Pinpointing the locus of GABAergic vulnerability in Alzheimer's disease. Semin Cell Dev Biol 2023; 139:35-54. [PMID: 35963663 DOI: 10.1016/j.semcdb.2022.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 06/30/2022] [Accepted: 06/30/2022] [Indexed: 12/31/2022]
Abstract
The early stages of Alzheimer's disease (AD) have been linked to microcircuit dysfunction and pathophysiological neuronal firing in several brain regions. Inhibitory GABAergic microcircuitry is a critical feature of stable neural-circuit function in the healthy brain, and its dysregulation has therefore been proposed as contributing to AD-related pathophysiology. However, exactly how the critical balance between excitatory and inhibitory microcircuitry is modified by AD pathogenesis remains unclear. Here, we set the current evidence implicating dysfunctional GABAergic microcircuitry as a driver of early AD pathophysiology in a simple conceptual framework. Our framework is based on a generalised reductionist model of firing-rate control by local feedback inhibition. We use this framework to consider multiple loci that may be vulnerable to disruption by AD pathogenesis. We first start with evidence investigating how AD-related processes may impact the gross number of inhibitory neurons in the network. We then move to discuss how pathology may impact intrinsic cellular properties and firing thresholds of GABAergic neurons. Finally, we cover how AD-related pathogenesis may disrupt synaptic connectivity between excitatory and inhibitory neurons. We use the feedback inhibition framework to discuss and organise the available evidence from both preclinical rodent work and human studies in AD patients and conclude by identifying key questions and understudied areas for future investigation.
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Affiliation(s)
- Leire Melgosa-Ecenarro
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Nazanin Doostdar
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Carola I Radulescu
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Johanna S Jackson
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Samuel J Barnes
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.
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Early death in a mouse model of Alzheimer's disease exacerbated by microglial loss of TAM receptor signaling. Proc Natl Acad Sci U S A 2022; 119:e2204306119. [PMID: 36191221 PMCID: PMC9564325 DOI: 10.1073/pnas.2204306119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recurrent seizure is a common comorbidity in early-stage Alzheimer's disease (AD) and may contribute to AD pathogenesis and cognitive decline. Similarly, many mouse models of Alzheimer's disease that overproduce amyloid beta are prone to epileptiform seizures that may result in early sudden death. We studied one such model, designated APP/PS1, and found that mutation of the TAM receptor tyrosine kinase (RTK) Mer or its ligand Gas6 greatly exacerbated early death. Lethality was tied to violent seizures that appeared to initiate in the dentate gyrus (DG) of the hippocampus, where Mer plays an essential role in the microglial phagocytosis of both apoptotic and newborn cells normally generated during adult neurogenesis. We found that newborn DG neurons and excitatory synapses between the DG and the cornu ammonis field 3 (CA3) field of the hippocampus were increased in TAM-deficient mice, and that premature death and adult neurogenesis in these mice were coincident. In contrast, the incidence of lethal seizures and the deposition of dense-core amyloid plaques were strongly anticorrelated. Together, these results argue that TAM-mediated phagocytosis sculpts synaptic connectivity in the hippocampus, and that seizure-inducing amyloid beta polymers are present prior to the formation of dense-core plaques.
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Baker J, Schott J. AD and its comorbidities: An obstacle to develop a clinically efficient treatment? Rev Neurol (Paris) 2022; 178:450-459. [DOI: 10.1016/j.neurol.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/08/2022] [Indexed: 10/18/2022]
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10
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Mechanisms Involved in Epileptogenesis in Alzheimer's Disease and Their Therapeutic Implications. Int J Mol Sci 2022; 23:ijms23084307. [PMID: 35457126 PMCID: PMC9030029 DOI: 10.3390/ijms23084307] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/09/2022] [Accepted: 04/11/2022] [Indexed: 12/22/2022] Open
Abstract
Epilepsy and Alzheimer's disease (AD) incidence increases with age. There are reciprocal relationships between epilepsy and AD. Epilepsy is a risk factor for AD and, in turn, AD is an independent risk factor for developing epilepsy in old age, and abnormal AD biomarkers in PET and/or CSF are frequently found in late-onset epilepsies of unknown etiology. Accordingly, epilepsy and AD share pathophysiological processes, including neuronal hyperexcitability and an early excitatory-inhibitory dysregulation, leading to dysfunction in the inhibitory GABAergic and excitatory glutamatergic systems. Moreover, both β-amyloid and tau protein aggregates, the anatomopathological hallmarks of AD, have proepileptic effects. Finally, these aggregates have been found in the resection material of refractory temporal lobe epilepsies, suggesting that epilepsy leads to amyloid and tau aggregates. Some epileptic syndromes, such as medial temporal lobe epilepsy, share structural and functional neuroimaging findings with AD, leading to overlapping symptomatology, such as episodic memory deficits and toxic synergistic effects. In this respect, the existence of epileptiform activity and electroclinical seizures in AD appears to accelerate the progression of cognitive decline, and the presence of cognitive decline is much more prevalent in epileptic patients than in elderly patients without epilepsy. Notwithstanding their clinical significance, the diagnosis of clinical seizures in AD is a challenge. Most are focal and manifest with an altered level of consciousness without motor symptoms, and are often interpreted as cognitive fluctuations. Finally, despite the frequent association of epilepsy and AD dementia, there is a lack of clinical trials to guide the use of antiseizure medications (ASMs). There is also a potential role for ASMs to be used as disease-modifying drugs in AD.
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Cope ZA, Murai T, Sukoff Rizzo SJ. Emerging Electroencephalographic Biomarkers to Improve Preclinical to Clinical Translation in Alzheimer's Disease. Front Aging Neurosci 2022; 14:805063. [PMID: 35250541 PMCID: PMC8891809 DOI: 10.3389/fnagi.2022.805063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/26/2022] [Indexed: 11/18/2022] Open
Abstract
Continually emerging data indicate that sub-clinical, non-convulsive epileptiform activity is not only prevalent in Alzheimer's disease (AD) but is detectable early in the course of the disease and predicts cognitive decline in both humans and animal models. Epileptiform activity and other electroencephalographic (EEG) measures may hold powerful, untapped potential to improve the translational validity of AD-related biomarkers in model animals ranging from mice, to rats, and non-human primates. In this review, we will focus on studies of epileptiform activity, EEG slowing, and theta-gamma coupling in preclinical models, with particular focus on its role in cognitive decline and relevance to AD. Here, each biomarker is described in the context of the contemporary literature and recent findings in AD relevant animal models are discussed.
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Affiliation(s)
| | | | - Stacey J. Sukoff Rizzo
- Aging Institute, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Du P, Li X, Yang Y, Fan X, Fang X, Zhou Z. Enhanced coagulation by two-stage alum addition: the role of solution pH, floc breakage and assistant of non-ionic polyacrylamide. ENVIRONMENTAL TECHNOLOGY 2021; 42:4456-4465. [PMID: 32345190 DOI: 10.1080/09593330.2020.1762757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
Coagulation process is highly influenced by solution pH, floc breakage, and coagulant aid. In this work, two-stage addition of alum-based coagulants, polyaluminum chloride (PACl) and aluminum sulfate (Al2(SO4)3), was compared to their one-stage addition with the same total dosage. The dose ratio of primary and secondary addition was optimised. The effects of solution pH, floc breakage and dosing timing of coagulant aid of non-ionic polyacrylamide (NPAM) on coagulation efficiency and floc property were investigated. The results showed that two-stage addition of PACl showed less sensitivity with the variation of pH. Compared to PACl, two-stage addition of Al2(SO4)3 was more sensitive to the solution pH, especially when the pH ranged from 7 to 10. For all cases, the presence of floc breakage improved the removal of colloidal particles. The coagulation mechanism of primary coagulant was charge neutralisation, while other mechanism was involved with the secondary addition of coagulant. Compared to one-stage addition, the settling performance of aggregates and particulates removal in two-stage addition was more effective with the variation of dosage or dosing timing of NPAM. The present work provides detailed operating parameters for this coagulation strategy.
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Affiliation(s)
- Peng Du
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing, People's Republic of China
| | - Xing Li
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing, People's Republic of China
| | - Yanling Yang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing, People's Republic of China
| | - Xiaoyan Fan
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing, People's Republic of China
| | - Xiaobo Fang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing, People's Republic of China
| | - Zhiwei Zhou
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing, People's Republic of China
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Haoudy S, Jonveaux T, Puisieux S, Epstein J, Hopes L, Maillard L, Aron O, Tyvaert L. Epilepsy in Early Onset Alzheimer's Disease. J Alzheimers Dis 2021; 85:615-626. [PMID: 34864663 DOI: 10.3233/jad-210681] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Epilepsy seems to be an important comorbidity in patients with early onset Alzheimer's disease (EOAD). Currently, seizures are still underestimated in this population. However, seizures may interact with AD evolution with possible acceleration of cognitive decline. OBJECTIVE To better define the epileptic disorders observed in patients with EOAD. METHODS All patients diagnosed as EOAD in our hospital between 2013 and 2019 with positive CSF biomarkers for AD were selected. The usual follow-up was extended with a 3-h EEG and a consultation with an epilepsy expert. Information on epilepsy and AD were collected and analyzed. RESULTS Among the 25 included patients, 10 (40%) were classified as epileptic. Seizure types were tonic-clonic (25%), typical temporal seizures (25%), myoclonus (25%), focal extra-temporal seizures (8%), and other seizure types (17%). AD-E patients had a significant lower MMSE (15.3±8.4 AD-E versus 22.1±5.1 AD-NE, p = 0.036) and a lower autonomy (IADL 4.1±2.7 AD-E versus 6.4±1.9 AD-NE, p = 0.046) at AD diagnosis with comparable ages between AD-E and AD-NE. Epileptic patients seemed to present a faster cognitive decline ([ΔMMSE per year 1.7±1.3 AD-E versus 0.9±1.4 AD-NE; p = 0.09). All patients with severe cognitive impairment (MMSE ≤ 10) had an epileptic comorbidity. CONCLUSION Epilepsy is a frequent comorbidity in EOAD patients, with a percentage of 40%in our study. This comorbidity may be associated with a severe form of EOAD. The role of epilepsy in the acceleration of cognitive decline and the positive impact of antiepileptic drugs on cognition need further research.
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Affiliation(s)
- Sarah Haoudy
- Department of Neurology, University Hospital Nancy, France
| | - Thérèse Jonveaux
- Department of Neurology, University Hospital Nancy, France.,CMRR, University Hospital Nancy, France.,Laboratoire Lorrain de Psychologie et deNeurosciences de la Dynamique des Comportements 2LPN EA 7489
| | | | - Jonathan Epstein
- Department of Clinical Epidemiology, INSERM, University of Lorraine and University Hospital Nancy, France
| | - Lucie Hopes
- Department of Neurology, University Hospital Nancy, France
| | - Louis Maillard
- Department of Neurology, University Hospital Nancy, France.,UMR 7039 CRAN Nancy, France.,University of Lorraine Nancy, France
| | - Olivier Aron
- Department of Neurology, University Hospital Nancy, France.,UMR 7039 CRAN Nancy, France
| | - Louise Tyvaert
- Department of Neurology, University Hospital Nancy, France.,UMR 7039 CRAN Nancy, France.,University of Lorraine Nancy, France
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14
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Romoli M, Sen A, Parnetti L, Calabresi P, Costa C. Amyloid-β: a potential link between epilepsy and cognitive decline. Nat Rev Neurol 2021; 17:469-485. [PMID: 34117482 DOI: 10.1038/s41582-021-00505-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2021] [Indexed: 02/05/2023]
Abstract
People with epilepsy - in particular, late-onset epilepsy of unknown aetiology - have an elevated risk of dementia, and seizures have been detected in the early stages of Alzheimer disease (AD), supporting the concept of an epileptic AD prodrome. However, the relationship between epilepsy and cognitive decline remains controversial, with substantial uncertainties about whether epilepsy drives cognitive decline or vice versa, and whether shared pathways underlie both conditions. Here, we review evidence that amyloid-β (Aβ) forms part of a shared pathway between epilepsy and cognitive decline, particularly in the context of AD. People with epilepsy show an increased burden of Aβ pathology in the brain, and Aβ-mediated epileptogenic alterations have been demonstrated in experimental studies, with evidence suggesting that Aβ pathology might already be pro-epileptogenic at the soluble stage, long before plaque deposition. We discuss the hypothesis that Aβ mediates - or is at least a major determinant of - a continuum spanning epilepsy and cognitive decline. Serial cognitive testing and assessment of Aβ levels might be worthwhile to stratify the risk of developing dementia in people with late-onset epilepsy. If seizures are a clinical harbinger of dementia, people with late-onset epilepsy could be an ideal group in which to implement preventive or therapeutic strategies to slow cognitive decline.
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Affiliation(s)
- Michele Romoli
- Neurology Clinic, Department of Medicine and Surgery, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy.,Oxford Epilepsy Research Group, NIHR Biomedical Research Centre, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK.,Neurology and Stroke Unit, "Maurizio Bufalini" Hospital, Cesena, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, Neurologia e Rete Stroke Metropolitana, Ospedale Maggiore, Bologna, Italy
| | - Arjune Sen
- Oxford Epilepsy Research Group, NIHR Biomedical Research Centre, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Lucilla Parnetti
- Neurology Clinic, Department of Medicine and Surgery, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy
| | - Paolo Calabresi
- Dipartimento di Neuroscienze, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A. Gemelli, IRCCS, UOC Neurologia, Dipartimento di Scienze dell'Invecchiamento, Neurologiche, Ortopediche e della Testa-Collo, Rome, Italy
| | - Cinzia Costa
- Neurology Clinic, Department of Medicine and Surgery, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy.
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15
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Altuna M, Giménez S, Fortea J. Epilepsy in Down Syndrome: A Highly Prevalent Comorbidity. J Clin Med 2021; 10:2776. [PMID: 34202784 PMCID: PMC8268854 DOI: 10.3390/jcm10132776] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/14/2022] Open
Abstract
Individuals with Down syndrome (DS) have an increased risk for epilepsy during the whole lifespan, but especially after age 40 years. The increase in the number of individuals with DS living into late middle age due to improved health care is resulting in an increase in epilepsy prevalence in this population. However, these epileptic seizures are probably underdiagnosed and inadequately treated. This late onset epilepsy is linked to the development of symptomatic Alzheimer's disease (AD), which is the main comorbidity in adults with DS with a cumulative incidence of more than 90% of adults by the seventh decade. More than 50% of patients with DS and AD dementia will most likely develop epilepsy, which in this context has a specific clinical presentation in the form of generalized myoclonic epilepsy. This epilepsy, named late onset myoclonic epilepsy (LOMEDS) affects the quality of life, might be associated with worse cognitive and functional outcomes in patients with AD dementia and has an impact on mortality. This review aims to summarize the current knowledge about the clinical and electrophysiological characteristics, diagnosis and treatment of epileptic seizures in the DS population, with a special emphasis on LOMEDS. Raised awareness and a better understanding of epilepsy in DS from families, caregivers and clinicians could enable earlier diagnoses and better treatments for individuals with DS.
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Affiliation(s)
- Miren Altuna
- Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, 08041 Barcelona, Spain;
- Center of Biomedical Investigation Network for Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain
| | - Sandra Giménez
- Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, 08041 Barcelona, Spain;
- Multidisciplinary Sleep Unit, Respiratory Department, Hospital de la Santa Creu i Sant Pau, 08041 Barcelona, Spain
| | - Juan Fortea
- Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, 08041 Barcelona, Spain;
- Center of Biomedical Investigation Network for Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain
- Barcelona Down Medical Center, Fundació Catalana de Síndrome de Down, 08029 Barcelona, Spain
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16
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Lauterborn JC, Scaduto P, Cox CD, Schulmann A, Lynch G, Gall CM, Keene CD, Limon A. Increased excitatory to inhibitory synaptic ratio in parietal cortex samples from individuals with Alzheimer's disease. Nat Commun 2021; 12:2603. [PMID: 33972518 PMCID: PMC8110554 DOI: 10.1038/s41467-021-22742-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/24/2021] [Indexed: 02/08/2023] Open
Abstract
Synaptic disturbances in excitatory to inhibitory (E/I) balance in forebrain circuits are thought to contribute to the progression of Alzheimer's disease (AD) and dementia, although direct evidence for such imbalance in humans is lacking. We assessed anatomical and electrophysiological synaptic E/I ratios in post-mortem parietal cortex samples from middle-aged individuals with AD (early-onset) or Down syndrome (DS) by fluorescence deconvolution tomography and microtransplantation of synaptic membranes. Both approaches revealed significantly elevated E/I ratios for AD, but not DS, versus controls. Gene expression studies in an independent AD cohort also demonstrated elevated E/I ratios in individuals with AD as compared to controls. These findings provide evidence of a marked pro-excitatory perturbation of synaptic E/I balance in AD parietal cortex, a region within the default mode network that is overly active in the disorder, and support the hypothesis that E/I imbalances disrupt cognition-related shifts in cortical activity which contribute to the intellectual decline in AD.
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Affiliation(s)
- Julie C Lauterborn
- Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, CA, USA.
| | - Pietro Scaduto
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases. School of Medicine, University of Texas Medical Branch at Galveston, Galveston, USA
| | - Conor D Cox
- Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, CA, USA
| | - Anton Schulmann
- National Institute of Mental Health, Human Genetics Branch, Bethesda, MD, USA
| | - Gary Lynch
- Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, CA, USA
- Department of Psychiatry & Human Behavior, University of California at Irvine, Irvine, CA, 92697, USA
| | - Christine M Gall
- Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, CA, USA
| | - C Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | - Agenor Limon
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases. School of Medicine, University of Texas Medical Branch at Galveston, Galveston, USA.
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17
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Application of sodium alginate as a coagulant aid for mitigating membrane fouling induced by humic acid in dead-end ultrafiltration process. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.117421] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Vöglein J, Ricard I, Noachtar S, Kukull WA, Dieterich M, Levin J, Danek A. Seizures in Alzheimer's disease are highly recurrent and associated with a poor disease course. J Neurol 2020; 267:2941-2948. [PMID: 32488295 PMCID: PMC7501095 DOI: 10.1007/s00415-020-09937-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Seizures are an important comorbidity in Alzheimer's disease (AD). Conflicting results regarding clinical parameters associated with seizures in AD were previously reported. Data on seizure recurrence risk, a crucial parameter for treatment decisions, are lacking. METHODS National Alzheimer's Coordinating Center data were analyzed. Seizure prevalence in AD and an association with disease duration were investigated. Associations of seizures with age of AD onset and with cognitive and functional performance, and seizure recurrence risk were studied. RESULTS 20,745 individuals were investigated. In AD dementia, seizure recurrence risk was 70.4% within 7.5 months. Seizure history was associated with an earlier age of onset of cognitive symptoms (seizures vs. no seizures: 64.7 vs. 70.4 years; p < 0.0001) and worse cognitive and functional performance (mean MMSE score: 16.6 vs. 19.6; mean CDR-sum of boxes score: 9.3 vs. 6.8; p < 0.0001; adjusted for disease duration and age). Seizure prevalence increased with duration of AD dementia (standardized OR = 1.55, 95% CI = 1.39-1.73, p < 0.0001), rising from 1.51% at 4.8 years to 5.43% at 11 years disease duration. Seizures were more frequent in AD dementia compared to normal controls (active seizures: 1.51% vs. 0.35%, p < 0.0001, OR = 4.34, 95% CI = 3.01-6.27; seizure history: 3.14% vs. 1.57%, p < 0.0001, OR = 2.03, 95% CI = 1.67-2.46). CONCLUSION Seizures in AD dementia feature an exceptionally high recurrence risk and are associated with a poor course of cognitive symptoms. AD patients are at an increased risk for seizures, particularly in later disease stages. Our findings emphasize a need for seizure history assessment in AD, inform individual therapeutic decisions and underline the necessity of systematic treatment studies of AD-associated epilepsy.
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Affiliation(s)
- Jonathan Vöglein
- German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Straße 17, 81377, Munich, Germany
- Department of Neurology, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany
| | - Ingrid Ricard
- Institute for Medical Informatics, Biometry and Epidemiology, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany
| | - Soheyl Noachtar
- Department of Neurology, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany
| | - Walter A Kukull
- Department of Epidemiology, University of Washington School of Public Health, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Marianne Dieterich
- German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Straße 17, 81377, Munich, Germany
- Department of Neurology, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Straße 17, 81377, Munich, Germany
- German Center for Vertigo and Balance Disorders, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany
| | - Johannes Levin
- German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Straße 17, 81377, Munich, Germany.
- Department of Neurology, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany.
- Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Straße 17, 81377, Munich, Germany.
| | - Adrian Danek
- German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Straße 17, 81377, Munich, Germany.
- Department of Neurology, Ludwig-Maximilians University, Marchioninistraße 15, 81377, Munich, Germany.
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19
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Abstract
Mutations in the presenilin-1 gene (PSEN1) on chromosome 14 are the most common cause of autosomal dominant Alzheimer's disease (ADAD), which has a broad clinical phenotype, encompassing not only dementia but a variety of other neurological features. We report the case of a 32 years old man with a family history of early onset AD associated with a PSEN1 mutation in the exon 4 (I83T). The proband's, carrying the mutation, present a refractory epilepsy predating cognitive decline. We discuss the physiopathological mechanisms of epilepsy during AD associated with PSEN 1 mutation, the possibility of linking this epilepsy to the mutation?.
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Affiliation(s)
- Saloua Fray
- Neurology Department, Charles Nicolle Hospital , Tunis, Tunisia.,Faculty of Medicine, Tunis El Manar University , Tunis, Tunisia
| | - Afef Rassas
- Neurology Department, Charles Nicolle Hospital , Tunis, Tunisia.,Biochemistry and Molecular Biology Laboratory, Children's Hospital - Bab Saadoun , Tunis, Tunisia
| | - Taieb Messaoud
- Biochemistry and Molecular Biology Laboratory, Children's Hospital - Bab Saadoun , Tunis, Tunisia
| | - Samir Belal
- Faculty of Medicine, Tunis El Manar University , Tunis, Tunisia
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20
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Kanyo R, Leighton PLA, Neil GJ, Locskai LF, Allison WT. Amyloid-β precursor protein mutant zebrafish exhibit seizure susceptibility that depends on prion protein. Exp Neurol 2020; 328:113283. [PMID: 32165257 DOI: 10.1016/j.expneurol.2020.113283] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 02/03/2020] [Accepted: 03/08/2020] [Indexed: 12/11/2022]
Abstract
It has been proposed that Amyloid β Precursor Protein (APP) might act as a rheostat controlling neuronal excitability, but mechanisms have remained untested. APP and its catabolite Aβ are known to impact upon synapse function and dysfunction via their interaction with the prion protein (PrPC), suggesting a candidate pathway. Here we test if PrPC is required for this APP function in vivo, perhaps via modulating mGluR5 ion channels. We engineered zebrafish to lack homologs of PrPC and APP, allowing us to assess their purported genetic and physiological interactions in CNS development. We generated four appa null alleles as well as prp1-/-;appa-/- double mutants (engineering of prp1 mutant alleles is described elsewhere). Unexpectedly, appa-/- and compound prp1-/-;appa-/- mutants are viable and lacked overt phenotypes (except being slightly smaller than wildtype fish at some developmental stages). Zebrafish prp1-/- mutants were substantially more sensitive to appa knockdown than wildtype fish, and both zebrafish prp1 and mammalian Prnp mRNA were significantly able to partially rescue this effect. Further, appa-/- mutants exhibited increased seizures upon exposure to low doses of convulsant. The mechanism of this seizure susceptibility requires prp1 insomuch that seizures were significantly dampened to wildtype levels in prp1-/-;appa-/- mutants. Inhibiting mGluR5 channels, which may be downstream of PrPC, increased seizure intensity only in prp1-/- mutants, and this seizure mechanism required intact appa. Taken together, these results support an intriguing genetic interaction between prp1 and appa with their shared roles impacting upon neuron hyperexcitability, thus complementing and extending past works detailing their biochemical interaction(s).
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Affiliation(s)
- Richard Kanyo
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Patricia L A Leighton
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Gavin J Neil
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Laszlo F Locskai
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - W Ted Allison
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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21
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Villa C, Suphesiz H, Combi R, Akyuz E. Potassium channels in the neuronal homeostasis and neurodegenerative pathways underlying Alzheimer's disease: An update. Mech Ageing Dev 2019; 185:111197. [PMID: 31862274 DOI: 10.1016/j.mad.2019.111197] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/27/2019] [Accepted: 12/12/2019] [Indexed: 02/06/2023]
Abstract
With more than 80 subunits, potassium (K+) channels represent a group of ion channels showing high degree of diversity and ubiquity. They play important role in the control of membrane depolarization and cell excitability in several tissues, including the brain. Controlling the intracellular and extracellular K+ flow in cells, they also modulate the hormone and neurotransmitter release, apoptosis and cell proliferation. It is therefore not surprising that an improper functioning of K+ channels in neurons has been associated with pathophysiology of a wide range of neurological disorders, especially Alzheimer's disease (AD). This review aims to give a comprehensive overview of the basic properties and pathophysiological functions of the main classes of K+ channels in the context of disease processes, also discussing the progress, challenges and opportunities to develop drugs targeting these channels as potential pharmacological approach for AD treatment.
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Affiliation(s)
- Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, Italy
| | | | - Romina Combi
- School of Medicine and Surgery, University of Milano-Bicocca, Italy
| | - Enes Akyuz
- Yozgat Bozok University, Medical Faculty, Department of Biophysics, Yozgat, Turkey.
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22
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Paudel YN, Angelopoulou E, Jones NC, O’Brien TJ, Kwan P, Piperi C, Othman I, Shaikh MF. Tau Related Pathways as a Connecting Link between Epilepsy and Alzheimer's Disease. ACS Chem Neurosci 2019; 10:4199-4212. [PMID: 31532186 DOI: 10.1021/acschemneuro.9b00460] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Emerging findings point toward an important interconnection between epilepsy and Alzheimer's disease (AD) pathogenesis. Patients with epilepsy (PWE) commonly exhibit cognitive impairment similar to AD patients, who in turn are at a higher risk of developing epilepsy compared to age-matched controls. To date, no disease-modifying treatment strategy is available for either epilepsy or AD, reflecting an immediate need for exploring common molecular targets, which can delineate a possible mechanistic link between epilepsy and AD. This review attempts to disentangle the interconnectivity between epilepsy and AD pathogenesis via the crucial contribution of Tau protein. Tau protein is a microtubule-associated protein (MAP) that has been implicated in the pathophysiology of both epilepsy and AD. Hyperphosphorylation of Tau contributes to the different forms of human epilepsy and inhibition of the same exerted seizure inhibitions and altered disease progression in a range of animal models. Moreover, Tau-protein-mediated therapy has demonstrated promising outcomes in experimental models of AD. In this review, we discuss how Tau-related mechanisms might present a link between the cause of seizures in epilepsy and cognitive disruption in AD. Untangling this interconnection might be instrumental in designing novel therapies that can minimize epileptic seizures and cognitive deficits in patients with epilepsy and AD.
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Affiliation(s)
- Yam Nath Paudel
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor 46150, Malaysia
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens 10679, Greece
| | - Nigel C. Jones
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne 3800, Australia
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Royal Parade, Parkville, Victoria 3010, Australia
| | - Terence J. O’Brien
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne 3800, Australia
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Royal Parade, Parkville, Victoria 3010, Australia
| | - Patrick Kwan
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne 3800, Australia
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Royal Parade, Parkville, Victoria 3010, Australia
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens 10679, Greece
| | - Iekhsan Othman
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor 46150, Malaysia
| | - Mohd. Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor 46150, Malaysia
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne 3800, Australia
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23
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Du P, Li X, Yang Y, Su Z, Li H, Wang N, Guo T, Zhang T, Zhou Z. Optimized coagulation pretreatment alleviates ultrafiltration membrane fouling: The role of floc properties and slow-mixing speed on mechanisms of chitosan-assisted coagulation. J Environ Sci (China) 2019; 82:82-92. [PMID: 31133272 DOI: 10.1016/j.jes.2019.02.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 06/09/2023]
Abstract
To alleviate ultrafiltration (UF) membrane fouling, the pre-coagulation of poly-aluminum chloride (PACl) with the aid of chitosan (CTS) was conducted for synthetic humic acid-kaolin water treatment. Pre-coagulation of three molecular weights (MW) CTSs (50-190 kDa (CTSL), 190-310 kDa (CTSM) and 310-375 kDa (CTSH)) was optimized with slow-mixing speeds of 30, 60 and 90 r/min, respectively. The removal efficiency and floc properties as well as membrane fouling were analyzed, and were compared to results obtained by conventional coagulation with PACl. Results showed that variations in floc properties could be ascribed to the coagulation mechanisms of CTSL/CTSM/CTSH at different slow-mixing speeds, resulting in reduced UF membrane fouling. Specifically, at the low speed of 30 r/min, all three CTS types produced flocs with similar properties, while CTSL resulted in the lowest removal efficiency and aggravated irreversible fouling. At the appropriate speed of 60 r/min, CTSM generated the most compact flocs with the combined effects of bridging and path mechanisms. The compact cake layer formed could alleviate irreversible fouling, which was beneficial for prolonging the operation of the UF membrane. At the high speed of 90 r/min, CTSH formed fragile flocs and aggravated irreversible membrane fouling. We considered membrane fouling to be affected by floc properties and the resultant removal efficiency, which was governed by the MW of the CTS used and the slow-mixing speed applied as well.
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Affiliation(s)
- Peng Du
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Xing Li
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Yanling Yang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Zhaoyang Su
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Hang Li
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Nan Wang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Tingting Guo
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Tingting Zhang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Zhiwei Zhou
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China.
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24
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Powell G, Ziso B, Larner AJ. The overlap between epilepsy and Alzheimer's disease and the consequences for treatment. Expert Rev Neurother 2019; 19:653-661. [PMID: 31238746 DOI: 10.1080/14737175.2019.1629289] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Introduction: Alzheimer's disease may be associated with both clinical and subclinical epileptic seizure activity. Once regarded as an epiphenomenon, epileptiform activity may, in fact, be an integral part of the Alzheimer's phenotype, and may be not only a symptomatic therapeutic target but also a possible mechanism to retard or prevent disease progression. Areas covered: The authors review clinical research articles with a focus on the semiology, epidemiology, and treatment of seizures in Alzheimer's disease, and also look at some experimental animal model studies which have informed clinical thinking on seizure aetiopathogenesis. The evidence base for treatment decisions is sparse. A brief overview of the clinical assessment of Alzheimer's disease patients considering relevant differential diagnoses and diagnostic pitfalls is presented. Expert opinion: Studies of epileptic seizures in Alzheimer's disease have become more frequent over the last 5-10 years. Understanding of seizure semiology, epidemiology, and possible pathogenesis has increased. However, the optimal management of seizures in this context remains unknown, largely due to the paucity of studies sufficient to examine this question. Clearly, such studies will be required, not only to inform clinicians about symptomatic control of seizures in Alzheimer's disease but also to investigate whether this might impact on disease progression.
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Affiliation(s)
- Graham Powell
- a Mersey Regional Epilepsy Clinic , Walton Centre for Neurology and Neurosurgery , Liverpool , UK
| | - Besa Ziso
- a Mersey Regional Epilepsy Clinic , Walton Centre for Neurology and Neurosurgery , Liverpool , UK
| | - A J Larner
- b Cognitive Function Clinic , Walton Centre for Neurology and Neurosurgery , Liverpool , UK
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