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Ewens AN, Pilski A, Hastings SD, Krook-Magnuson C, Graves SM, Krook-Magnuson E, Thayer SA. Levetiracetam Prevents Neurophysiological Changes and Preserves Cognitive Function in the Human Immunodeficiency Virus (HIV)-1 Transactivator of Transcription Transgenic Mouse Model of HIV-Associated Neurocognitive Disorder. J Pharmacol Exp Ther 2024; 391:104-118. [PMID: 39060163 PMCID: PMC11413936 DOI: 10.1124/jpet.124.002272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/24/2024] [Accepted: 07/22/2024] [Indexed: 07/28/2024] Open
Abstract
Human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) affects nearly half of the 39 million people living with HIV. HAND symptoms range from subclinical cognitive impairment to dementia; the mechanisms that underlie HAND remain unclear and there is no treatment. The HIV protein transactivator of transcription (TAT) is thought to contribute to HAND because it persists in the central nervous system and elicits neurotoxicity in animal models. Network hyperexcitability is associated with accelerated cognitive decline in neurodegenerative disorders. Here we show that the antiepileptic drug levetiracetam (LEV) attenuated aberrant excitatory synaptic transmission, protected synaptic plasticity, reduced seizure susceptibility, and preserved cognition in inducible TAT (iTAT) transgenic male mice. iTAT mice had an increased frequency of spontaneous excitatory postsynaptic currents in hippocampal slice recordings and impaired long-term potentiation, a form of synaptic plasticity that underlies learning and memory. Two-week administration of LEV by osmotic minipump prevented both impairments. Kainic acid administered to iTAT mice induced a higher maximum behavioral seizure score, longer seizure duration, and shorter latency to first seizure, consistent with a lower seizure threshold. LEV treatment prevented these in vivo signs of hyperexcitability. Lastly, in the Barnes maze, iTAT mice required more time to reach the goal, committed more errors, and received lower cognitive scores relative to iTAT mice treated with LEV. Thus, TAT expression drives functional deficits, suggesting a causative role in HAND. As LEV not only prevented aberrant synaptic activity in iTAT mice but also prevented cognitive dysfunction, it may provide a promising pharmacological approach to the treatment of HAND. SIGNIFICANCE STATEMENT: Approximately half of people living with human immunodeficiency virus (HIV) also suffer from HIV-associated neurocognitive disorder (HAND), for which there is no treatment. The HIV protein transactivator of transcription (TAT) causes toxicity that is thought to contribute to HAND. Here, the antiepileptic drug levetiracetam (LEV) prevented synaptic and cognitive impairments in a TAT-expressing mouse. LEV is widely used to treat seizures and is well-tolerated in humans, including those with HIV. This study supports further investigation of LEV-mediated neuroprotection in HAND.
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Affiliation(s)
- Ashley N Ewens
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Alexander Pilski
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Shayne D Hastings
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Chris Krook-Magnuson
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Steven M Graves
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Esther Krook-Magnuson
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Stanley A Thayer
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
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2
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Almeida VN. Somatostatin and the pathophysiology of Alzheimer's disease. Ageing Res Rev 2024; 96:102270. [PMID: 38484981 DOI: 10.1016/j.arr.2024.102270] [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: 07/18/2023] [Revised: 03/09/2024] [Accepted: 03/09/2024] [Indexed: 03/28/2024]
Abstract
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.
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Affiliation(s)
- Victor N Almeida
- Institute of Psychiatry, Faculty of Medicine, University of São Paulo (USP), Brazil; Faculty of Languages, Federal University of Minas Gerais (UFMG), Brazil.
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3
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Ashford JW. Neuroplasticity: The Critical Issue for Alzheimer's Disease and Links to Obesity and Depression. Am J Geriatr Psychiatry 2023; 31:867-875. [PMID: 37481402 DOI: 10.1016/j.jagp.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/24/2023]
Affiliation(s)
- J Wesson Ashford
- Department of Psychiatry & Behavioral Sciences, VA Palo Alto Health Care System, Stanford University, Palo Alto, CA.
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4
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Bosco F, Guarnieri L, Rania V, Palma E, Citraro R, Corasaniti MT, Leo A, De Sarro G. Antiseizure Medications in Alzheimer's Disease from Preclinical to Clinical Evidence. Int J Mol Sci 2023; 24:12639. [PMID: 37628821 PMCID: PMC10454935 DOI: 10.3390/ijms241612639] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/06/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Alzheimer's disease (AD) and epilepsy are common neurological disorders in the elderly. A bi-directional link between these neurological diseases has been reported, with patients with either condition carrying almost a two-fold risk of contracting the other compared to healthy subjects. AD/epilepsy adversely affects patients' quality of life and represents a severe public health problem. Thus, identifying the relationship between epilepsy and AD represents an ongoing challenge and continuing need. Seizures in AD patients are often unrecognized because they are often nonconvulsive and sometimes mimic some behavioral symptoms of AD. Regarding this, it has been hypothesized that epileptogenesis and neurodegeneration share common underlying mechanisms. Targeted treatment to decrease epileptiform activity could represent a valuable strategy for delaying the neurodegenerative process and related cognitive impairment. Several preclinical studies have shown that some antiseizure medications (ASMs) targeting abnormal network hyperexcitability may change the natural progression of AD. However, to date, no guidelines are available for managing seizures in AD patients because of the paucity of randomized clinical trials sufficient for answering the correlated questions. Future AD clinical studies are mandatory to update clinicians about the symptomatic treatment of seizures in AD patients and recognize whether ASM therapy could change the natural progression of the disease, thereby rescuing cognitive performance.
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Affiliation(s)
- Francesca Bosco
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (F.B.); (L.G.); (V.R.); (R.C.); (G.D.S.)
| | - Lorenza Guarnieri
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (F.B.); (L.G.); (V.R.); (R.C.); (G.D.S.)
| | - Vincenzo Rania
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (F.B.); (L.G.); (V.R.); (R.C.); (G.D.S.)
| | - Ernesto Palma
- Department of Health Sciences, School of Pharmacy, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (E.P.); (M.T.C.)
| | - Rita Citraro
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (F.B.); (L.G.); (V.R.); (R.C.); (G.D.S.)
- System and Applied Pharmacology, University Magna Graecia (FAS@UMG) Research Center, Department of Health Sciences, School of Medicine, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | - Maria Tiziana Corasaniti
- Department of Health Sciences, School of Pharmacy, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (E.P.); (M.T.C.)
| | - Antonio Leo
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (F.B.); (L.G.); (V.R.); (R.C.); (G.D.S.)
- System and Applied Pharmacology, University Magna Graecia (FAS@UMG) Research Center, Department of Health Sciences, School of Medicine, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | - Giovambattista De Sarro
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (F.B.); (L.G.); (V.R.); (R.C.); (G.D.S.)
- System and Applied Pharmacology, University Magna Graecia (FAS@UMG) Research Center, Department of Health Sciences, School of Medicine, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
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5
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Perone I, Ghena N, Wang J, Mackey C, Wan R, Malla S, Gorospe M, Cheng A, Mattson MP. Mitochondrial SIRT3 Deficiency Results in Neuronal Network Hyperexcitability, Accelerates Age-Related Aβ Pathology, and Renders Neurons Vulnerable to Aβ Toxicity. Neuromolecular Med 2023; 25:27-39. [PMID: 35749057 PMCID: PMC9810471 DOI: 10.1007/s12017-022-08713-2] [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: 03/31/2022] [Accepted: 06/01/2022] [Indexed: 01/05/2023]
Abstract
Aging is the major risk factor for Alzheimer's disease (AD). Mitochondrial dysfunction and neuronal network hyperexcitability are two age-related alterations implicated in AD pathogenesis. We found that levels of the mitochondrial protein deacetylase sirtuin-3 (SIRT3) are significantly reduced, and consequently mitochondria protein acetylation is increased in brain cells during aging. SIRT3-deficient mice exhibit robust mitochondrial protein hyperacetylation and reduced mitochondrial mass during aging. Moreover, SIRT3-deficient mice exhibit epileptiform and burst-firing electroencephalogram activity indicating neuronal network hyperexcitability. Both aging and SIRT3 deficiency result in increased sensitivity to kainic acid-induced seizures. Exposure of cultured cerebral cortical neurons to amyloid β-peptide (Aβ) results in a reduction in SIRT3 levels and SIRT3-deficient neurons exhibit heightened sensitivity to Aβ toxicity. Finally, SIRT3 haploinsufficiency in middle-aged App/Ps1 double mutant transgenic mice results in a significant increase in Aβ load compared with App/Ps1 double mutant mice with normal SIRT3 levels. Collectively, our findings suggest that SIRT3 plays an important role in protecting neurons against Aβ pathology and excitotoxicity.
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Affiliation(s)
- Isabella Perone
- Laboratory of Genetics and Genomics, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Nathaniel Ghena
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Jing Wang
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
- Department of Integrative Medicine and Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chelsea Mackey
- Department of Integrative Medicine and Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Laboratory of Cardiovascular Science, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Ruiqian Wan
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Sulochan Malla
- Laboratory of Genetics and Genomics, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Myriam Gorospe
- Laboratory of Genetics and Genomics, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Aiwu Cheng
- Laboratory of Genetics and Genomics, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA.
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA.
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA.
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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6
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Sciaccaluga M, Ruffolo G, Palma E, Costa C. Traditional and Innovative Anti-seizure Medications Targeting Key Physiopathological Mechanisms: Focus on Neurodevelopment and Neurodegeneration. Curr Neuropharmacol 2023; 21:1736-1754. [PMID: 37143270 PMCID: PMC10514539 DOI: 10.2174/1570159x21666230504160948] [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: 09/03/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 05/06/2023] Open
Abstract
Despite the wide range of compounds currently available to treat epilepsy, there is still no drug that directly tackles the physiopathological mechanisms underlying its development. Indeed, antiseizure medications attempt to prevent seizures but are inefficacious in counteracting or rescuing the physiopathological phenomena that underlie their onset and recurrence, and hence do not cure epilepsy. Classically, the altered excitation/inhibition balance is postulated as the mechanism underlying epileptogenesis and seizure generation. This oversimplification, however, does not account for deficits in homeostatic plasticity resulting from either insufficient or excessive compensatory mechanisms in response to a change in network activity. In this respect, both neurodevelopmental epilepsies and those associated with neurodegeneration may share common underlying mechanisms that still need to be fully elucidated. The understanding of these molecular mechanisms shed light on the identification of new classes of drugs able not only to suppress seizures, but also to present potential antiepileptogenic effects or "disease-modifying" properties.
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Affiliation(s)
- Miriam Sciaccaluga
- Section of Neurology, S.M. della Misericordia Hospital, Department of Medicine and Surgery, University of Perugia, Piazzale Gambuli 1, Perugia, 06129, Italy
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Istituto Pasteur—Fondazione Cenci Bolognetti, University of Rome, Sapienza, Rome, 00185, Italy
- IRCCS San Raffaele Roma, Rome, 00166, Italy
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Istituto Pasteur—Fondazione Cenci Bolognetti, University of Rome, Sapienza, Rome, 00185, Italy
- IRCCS San Raffaele Roma, Rome, 00166, Italy
| | - Cinzia Costa
- Section of Neurology, S.M. della Misericordia Hospital, Department of Medicine and Surgery, University of Perugia, Piazzale Gambuli 1, Perugia, 06129, Italy
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7
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Fernandez‐Perez EJ, Muñoz B, Bascuñan DA, Peters C, Riffo‐Lepe NO, Espinoza MP, Morgan PJ, Filippi C, Bourboulou R, Sengupta U, Kayed R, Epsztein J, Aguayo LG. Synaptic dysregulation and hyperexcitability induced by intracellular amyloid beta oligomers. Aging Cell 2021; 20:e13455. [PMID: 34409748 PMCID: PMC8441418 DOI: 10.1111/acel.13455] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/21/2021] [Accepted: 08/05/2021] [Indexed: 12/19/2022] Open
Abstract
Intracellular amyloid beta oligomer (iAβo) accumulation and neuronal hyperexcitability are two crucial events at early stages of Alzheimer's disease (AD). However, to date, no mechanism linking iAβo with an increase in neuronal excitability has been reported. Here, the effects of human AD brain-derived (h-iAβo) and synthetic (iAβo) peptides on synaptic currents and action potential firing were investigated in hippocampal neurons. Starting from 500 pM, iAβo rapidly increased the frequency of synaptic currents and higher concentrations potentiated the AMPA receptor-mediated current. Both effects were PKC-dependent. Parallel recordings of synaptic currents and nitric oxide (NO)-associated fluorescence showed that the increased frequency, related to pre-synaptic release, was dependent on a NO-mediated retrograde signaling. Moreover, increased synchronization in NO production was also observed in neurons neighboring those dialyzed with iAβo, indicating that iAβo can increase network excitability at a distance. Current-clamp recordings suggested that iAβo increased neuronal excitability via AMPA-driven synaptic activity without altering membrane intrinsic properties. These results strongly indicate that iAβo causes functional spreading of hyperexcitability through a synaptic-driven mechanism and offers an important neuropathological significance to intracellular species in the initial stages of AD, which include brain hyperexcitability and seizures.
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Affiliation(s)
| | - Braulio Muñoz
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Denisse A. Bascuñan
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Christian Peters
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Nicolas O. Riffo‐Lepe
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Maria P. Espinoza
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Peter J. Morgan
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Caroline Filippi
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Romain Bourboulou
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Urmi Sengupta
- Mitchell Center for Neurodegenerative DiseasesUniversity of Texas Medical BranchGalvestonTexasUSA
- Department of Neurology, Neuroscience and Cell BiologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative DiseasesUniversity of Texas Medical BranchGalvestonTexasUSA
- Department of Neurology, Neuroscience and Cell BiologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Jérôme Epsztein
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Luis G. Aguayo
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
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8
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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: 64] [Impact Index Per Article: 21.3] [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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9
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Carli G, Tondo G, Boccalini C, Perani D. Brain Molecular Connectivity in Neurodegenerative Conditions. Brain Sci 2021; 11:brainsci11040433. [PMID: 33800680 PMCID: PMC8067093 DOI: 10.3390/brainsci11040433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/15/2021] [Accepted: 03/23/2021] [Indexed: 12/28/2022] Open
Abstract
Positron emission tomography (PET) allows for the in vivo assessment of early brain functional and molecular changes in neurodegenerative conditions, representing a unique tool in the diagnostic workup. The increased use of multivariate PET imaging analysis approaches has provided the chance to investigate regional molecular processes and long-distance brain circuit functional interactions in the last decade. PET metabolic and neurotransmission connectome can reveal brain region interactions. This review is an overview of concepts and methods for PET molecular and metabolic covariance assessment with evidence in neurodegenerative conditions, including Alzheimer’s disease and Lewy bodies disease spectrum. We highlight the effects of environmental and biological factors on brain network organization. All of the above might contribute to innovative diagnostic tools and potential disease-modifying interventions.
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Affiliation(s)
- Giulia Carli
- School of Psychology, Vita-Salute San Raffaele University, 20121 Milan, Italy; (G.C.); (G.T.); (C.B.)
- In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20121 Milan, Italy
| | - Giacomo Tondo
- School of Psychology, Vita-Salute San Raffaele University, 20121 Milan, Italy; (G.C.); (G.T.); (C.B.)
- In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20121 Milan, Italy
| | - Cecilia Boccalini
- School of Psychology, Vita-Salute San Raffaele University, 20121 Milan, Italy; (G.C.); (G.T.); (C.B.)
- In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20121 Milan, Italy
| | - Daniela Perani
- School of Psychology, Vita-Salute San Raffaele University, 20121 Milan, Italy; (G.C.); (G.T.); (C.B.)
- In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20121 Milan, Italy
- Nuclear Medicine Unit, San Raffaele Hospital, 20121 Milan, Italy
- Correspondence: ; Tel.: +39-02-26432224
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10
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Romoli M, Mazzocchetti P, D'Alonzo R, Siliquini S, Rinaldi VE, Verrotti A, Calabresi P, Costa C. Valproic Acid and Epilepsy: From Molecular Mechanisms to Clinical Evidences. Curr Neuropharmacol 2020; 17:926-946. [PMID: 30592252 PMCID: PMC7052829 DOI: 10.2174/1570159x17666181227165722] [Citation(s) in RCA: 165] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/03/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022] Open
Abstract
After more than a century from its discovery, valproic acid (VPA) still represents one of the most efficient antiepi-leptic drugs (AEDs). Pre and post-synaptic effects of VPA depend on a very broad spectrum of actions, including the regu-lation of ionic currents and the facilitation of GABAergic over glutamatergic transmission. As a result, VPA indirectly mod-ulates neurotransmitter release and strengthens the threshold for seizure activity. However, even though participating to the anticonvulsant action, such mechanisms seem to have minor impact on epileptogenesis. Nonetheless, VPA has been reported to exert anti-epileptogenic effects. Epigenetic mechanisms, including histone deacetylases (HDACs), BDNF and GDNF modulation are pivotal to orientate neurons toward a neuroprotective status and promote dendritic spines organization. From such broad spectrum of actions comes constantly enlarging indications for VPA. It represents a drug of choice in child and adult with epilepsy, with either general or focal seizures, and is a consistent and safe IV option in generalized convulsive sta-tus epilepticus. Moreover, since VPA modulates DNA transcription through HDACs, recent evidences point to its use as an anti-nociceptive in migraine prophylaxis, and, even more interestingly, as a positive modulator of chemotherapy in cancer treatment. Furthermore, VPA-induced neuroprotection is under investigation for benefit in stroke and traumatic brain injury. Hence, VPA has still got its place in epilepsy, and yet deserves attention for its use far beyond neurological diseases. In this review, we aim to highlight, with a translational intent, the molecular basis and the clinical indications of VPA.
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Affiliation(s)
- Michele Romoli
- Neurology Clinic, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy
| | - Petra Mazzocchetti
- Neurology Clinic, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy
| | - Renato D'Alonzo
- Pediatric Clinic, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy
| | | | - Victoria Elisa Rinaldi
- Pediatric Clinic, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy
| | - Alberto Verrotti
- Department of Pediatrics, University of L'Aquila - San Salvatore Hospital, L'Aquila, Italy
| | - Paolo Calabresi
- Neurology Clinic, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy.,IRCCS "Santa Lucia", Rome, Italy
| | - Cinzia Costa
- Neurology Clinic, University of Perugia - S. Maria della Misericordia Hospital, Perugia, Italy
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Involvement of GABAergic interneuron dysfunction and neuronal network hyperexcitability in Alzheimer's disease: Amelioration by metabolic switching. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 154:191-205. [DOI: 10.1016/bs.irn.2020.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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SIRT3 Haploinsufficiency Aggravates Loss of GABAergic Interneurons and Neuronal Network Hyperexcitability in an Alzheimer's Disease Model. J Neurosci 2019; 40:694-709. [PMID: 31818974 DOI: 10.1523/jneurosci.1446-19.2019] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/26/2019] [Accepted: 11/05/2019] [Indexed: 01/17/2023] Open
Abstract
Impaired mitochondrial function and aberrant neuronal network activity are believed to be early events in the pathogenesis of Alzheimer's disease (AD), but how mitochondrial alterations contribute to aberrant activity in neuronal circuits is unknown. In this study, we examined the function of mitochondrial protein deacetylase sirtuin 3 (SIRT3) in the pathogenesis of AD. Compared with AppPs1 mice, Sirt3-haploinsufficient AppPs1 mice (Sirt3+/-AppPs1) exhibit early epileptiform EEG activity and seizure. Both male and female Sirt3+/-AppPs1 mice were observed to die prematurely before 5 months of age. When comparing male mice among different genotypes, Sirt3 haploinsufficiency renders GABAergic interneurons in the cerebral cortex vulnerable to degeneration and associated neuronal network hyperexcitability. Feeding Sirt3+/-AppPs1 AD mice with a ketone ester-rich diet increases SIRT3 expression and prevents seizure-related death and the degeneration of GABAergic neurons, indicating that the aggravated GABAergic neuron loss and neuronal network hyperexcitability in Sirt3+/-AppPs1 mice are caused by SIRT3 reduction and can be rescued by increase of SIRT3 expression. Consistent with a protective role in AD, SIRT3 levels are reduced in association with cerebral cortical Aβ pathology in AD patients. In summary, SIRT3 preserves GABAergic interneurons and protects cerebral circuits against hyperexcitability, and this neuroprotective mechanism can be bolstered by dietary ketone esters.SIGNIFICANCE STATEMENT GABAergic neurons provide the main inhibitory control of neuronal activity in the brain. By preserving mitochondrial function, SIRT3 protects parvalbumin and calretinin interneurons against Aβ-associated dysfunction and degeneration in AppPs1 Alzheimer's disease mice, thus restraining neuronal network hyperactivity. The neuronal network dysfunction that occurs in Alzheimer's disease can be partially reversed by physiological, dietary, and pharmacological interventions to increase SIRT3 expression and enhance the functionality of GABAergic interneurons.
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Calvo-Flores Guzmán B, Vinnakota C, Govindpani K, Waldvogel HJ, Faull RL, Kwakowsky A. The GABAergic system as a therapeutic target for Alzheimer's disease. J Neurochem 2018; 146:649-669. [DOI: 10.1111/jnc.14345] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 02/21/2018] [Accepted: 03/14/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Beatriz Calvo-Flores Guzmán
- Centre for Brain Research; Faculty of Medical and Health Sciences; Department of Anatomy and Medical Imaging; University of Auckland; Auckland New Zealand
| | - Chitra Vinnakota
- Centre for Brain Research; Faculty of Medical and Health Sciences; Department of Anatomy and Medical Imaging; University of Auckland; Auckland New Zealand
| | - Karan Govindpani
- Centre for Brain Research; Faculty of Medical and Health Sciences; Department of Anatomy and Medical Imaging; University of Auckland; Auckland New Zealand
| | - Henry J. Waldvogel
- Centre for Brain Research; Faculty of Medical and Health Sciences; Department of Anatomy and Medical Imaging; University of Auckland; Auckland New Zealand
| | - Richard L.M. Faull
- Centre for Brain Research; Faculty of Medical and Health Sciences; Department of Anatomy and Medical Imaging; University of Auckland; Auckland New Zealand
| | - Andrea Kwakowsky
- Centre for Brain Research; Faculty of Medical and Health Sciences; Department of Anatomy and Medical Imaging; University of Auckland; Auckland New Zealand
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14
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Liu D, Lu H, Stein E, Zhou Z, Yang Y, Mattson MP. Brain regional synchronous activity predicts tauopathy in 3×TgAD mice. Neurobiol Aging 2018; 70:160-169. [PMID: 30015035 DOI: 10.1016/j.neurobiolaging.2018.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/20/2018] [Accepted: 06/10/2018] [Indexed: 02/08/2023]
Abstract
Alzheimer's disease (AD) is characterized by progressive cognitive impairment and by extensive neuronal loss associated with extracellular amyloid β-peptide (Aβ) plaques and intraneuronal tau pathology in temporal and parietal lobes. AD patients are at increased risk for epileptic seizures, and data from experimental models of AD suggest that aberrant neuronal network activity occurs early in the disease process before cognitive deficits and neuronal degeneration. The contributions of Aβ and/or tau pathologies to dysregulation of neuronal network activity are unclear. Using a transgenic mouse model of AD (3×TgAD mice) in which there occurs differential age-dependent development of tau and Aβ plaque pathologies, we applied analysis of resting state functional magnetic resonance imaging regional homogeneity, a measure of local synchronous activity, to discriminate the effects of Aβ and tau on neuronal network activity throughout the brain. Compared to age-matched wild-type mice, 6- to 8-month-old 3×TgAD mice exhibited increased regional homogeneity in the hippocampus and parietal and temporal cortices, regions with tau pathology but not Aβ pathology at this age. By 18-24 months of age, 3×TgAD mice exhibited extensive tau and Aβ pathologies involving the hippocampus and multiple functionally related brain regions, with a spatial expansion of increased local synchronous activity to include those regions. Our findings demonstrate that age-related brain regional hypersynchronous activity is associated with early tau pathology in a mouse model, consistent with a role for early tau pathology in the neuronal circuit hyperexcitability that is believed to precede and contribute to neuronal degeneration in AD.
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Affiliation(s)
- Dong Liu
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - Hanbing Lu
- Neuroimaging Research Branch, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, USA
| | - Elliot Stein
- Neuroimaging Research Branch, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, USA
| | - Zhujuan Zhou
- Department of Neurology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Yihong Yang
- Neuroimaging Research Branch, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore MD, USA.
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15
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Durães F, Pinto M, Sousa E. Old Drugs as New Treatments for Neurodegenerative Diseases. Pharmaceuticals (Basel) 2018; 11:ph11020044. [PMID: 29751602 PMCID: PMC6027455 DOI: 10.3390/ph11020044] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative diseases are increasing in number, given that the general global population is becoming older. They manifest themselves through mechanisms that are not fully understood, in many cases, and impair memory, cognition and movement. Currently, no neurodegenerative disease is curable, and the treatments available only manage the symptoms or halt the progression of the disease. Therefore, there is an urgent need for new treatments for this kind of disease, since the World Health Organization has predicted that neurodegenerative diseases affecting motor function will become the second-most prevalent cause of death in the next 20 years. New therapies can come from three main sources: synthesis, natural products, and existing drugs. This last source is known as drug repurposing, which is the most advantageous, since the drug’s pharmacokinetic and pharmacodynamic profiles are already established, and the investment put into this strategy is not as significant as for the classic development of new drugs. There have been several studies on the potential of old drugs for the most relevant neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, Multiple Sclerosis and Amyotrophic Lateral Sclerosis.
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Affiliation(s)
- Fernando Durães
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- CIIMAR, Interdisciplinary Center of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos P, 4450-208 Matosinhos, Portugal.
| | - Madalena Pinto
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- CIIMAR, Interdisciplinary Center of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos P, 4450-208 Matosinhos, Portugal.
| | - Emília Sousa
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- CIIMAR, Interdisciplinary Center of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos P, 4450-208 Matosinhos, Portugal.
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16
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Zimmermann J, Perry A, Breakspear M, Schirner M, Sachdev P, Wen W, Kochan NA, Mapstone M, Ritter P, McIntosh AR, Solodkin A. Differentiation of Alzheimer's disease based on local and global parameters in personalized Virtual Brain models. NEUROIMAGE-CLINICAL 2018; 19:240-251. [PMID: 30035018 PMCID: PMC6051478 DOI: 10.1016/j.nicl.2018.04.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 04/05/2018] [Accepted: 04/14/2018] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease (AD) is marked by cognitive dysfunction emerging from neuropathological processes impacting brain function. AD affects brain dynamics at the local level, such as changes in the balance of inhibitory and excitatory neuronal populations, as well as long-range changes to the global network. Individual differences in these changes as they relate to behaviour are poorly understood. Here, we use a multi-scale neurophysiological model, “The Virtual Brain (TVB)”, based on empirical multi-modal neuroimaging data, to study how local and global dynamics correlate with individual differences in cognition. In particular, we modeled individual resting-state functional activity of 124 individuals across the behavioural spectrum from healthy aging, to amnesic Mild Cognitive Impairment (MCI), to AD. The model parameters required to accurately simulate empirical functional brain imaging data correlated significantly with cognition, and exceeded the predictive capacity of empirical connectomes. Modeled local and global dynamics correlate with individual cognition in Alzheimer's. Proof of concept of The Virtual Brain to characterize individual dynamics Brain-behaviour relations depend on the network modeled (whole brain or limbic). Model parameters predict cognition better than metrics of neuroimaging data.
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Affiliation(s)
- J Zimmermann
- Baycrest Health Sciences, Rotman Research Institute, 3560 Bathurst St, Toronto, Ontario M6A 2E1, Canada.
| | - A Perry
- Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia; Program of Mental Health Research, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany
| | - M Breakspear
- Program of Mental Health Research, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia; Metro North Mental Health Service, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia
| | - M Schirner
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Dept. of Neurology, Chariteplatz 1, Berlin 13353, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany
| | - P Sachdev
- Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - W Wen
- Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - N A Kochan
- Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - M Mapstone
- UC Irvine Health School of Medicine, Irvine Hall, 1001 Health Sciences Road, Irvine, CA 92697-3950, USA
| | - P Ritter
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Dept. of Neurology, Chariteplatz 1, Berlin 13353, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany
| | - A R McIntosh
- Baycrest Health Sciences, Rotman Research Institute, 3560 Bathurst St, Toronto, Ontario M6A 2E1, Canada
| | - A Solodkin
- UC Irvine Health School of Medicine, Irvine Hall, 1001 Health Sciences Road, Irvine, CA 92697-3950, USA
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17
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van Woerkom AE. A fully integrated new paradigm for lithium's mode of action - lithium utilizes latent cellular fail-safe mechanisms. Neuropsychiatr Dis Treat 2017; 13:275-302. [PMID: 28203080 PMCID: PMC5293501 DOI: 10.2147/ndt.s123612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It is proposed that lithium's therapeutic effects occur indirectly by augmenting a cascade of protective "fail-safe" pathways pre-configured to activate in response to a dangerous low cell [Mg++] situation, eg, posttraumatic brain injury, alongside relative cell adenosine triphosphate depletion. Lithium activates cell protection, as it neatly mimics a lowered intracellular [Mg++] level.
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Affiliation(s)
- Arthur Ernst van Woerkom
- South Birmingham and Solihull Mental Health NHS Foundation Trust, Longbridge CMHT, Rubery, Birmingham, UK
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18
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Chung JK, Nakajima S, Shinagawa S, Plitman E, Chakravarty MM, Iwata Y, Caravaggio F, Pollock BG, Gerretsen P, Graff-Guerrero A. Benzodiazepine Use Attenuates Cortical β-Amyloid and is Not Associated with Progressive Cognitive Decline in Nondemented Elderly Adults: A Pilot Study Using F 18-Florbetapir Positron Emission Tomography. Am J Geriatr Psychiatry 2016; 24:1028-1039. [PMID: 27538351 DOI: 10.1016/j.jagp.2016.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 04/20/2016] [Accepted: 04/29/2016] [Indexed: 12/18/2022]
Abstract
OBJECTIVE It is inconclusive as to whether benzodiazepines (BZDs) are related to cognitive deterioration in the elderly populations. Animal studies suggest that γ-aminobutyric acid A receptor agonists, such as BZDs, may prevent Aβ-neurotoxicity and reduce β-amyloid (Aβ). However, no studies have investigated the effects of BZD use on Aβ in humans. METHODS This cross-sectional, prospective study using Alzheimer's Disease Neuroimaging Initiative sites in the United States and Canada on nondemented elderly adults between 55 and 90 years of age assessed cortical Aβ levels by positron emission tomography radiotracer F18-Florbetapir. Changes in global cognitive function and verbal memory performance over 2 years were assessed using scores on Montreal Cognitive Assessment and five domains of Rey Auditory Verbal Learning Test, respectively. RESULTS Previous BZD users (N = 15) had lower cortical Aβ levels in frontal (F(1, 26) = 8.82, p = 0.006), cingulate (F(1, 26) = 8.58, p = 0.007), parietal (F(1, 26) = 7.31, p = 0.012), and temporal (F(1, 26) = 7.67, p = 0.010) regions compared with matched BZD nonusers (N = 15), after controlling for history of psychiatric disorders and antidepressant use. Also, no differences were found in global cognitive function and changes in cortical Aβ over 2 years between continuous BZD users (N = 15) andthe matched nonuser group (N = 15). CONCLUSION Previous BZD use was associated with lower cortical Aβ levels in nondemented elderly control subjects. Future studies with larger samples are required to replicate our findings.
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Affiliation(s)
- Jun Ku Chung
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Shinichiro Nakajima
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | | | - Eric Plitman
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - M Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health Institute, McGill University, Montreal, Quebec, Canada; Department of Psychiatry and Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Yusuke Iwata
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | - Fernando Caravaggio
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Bruce G Pollock
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Philip Gerretsen
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ariel Graff-Guerrero
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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Giorgi FS, Guida M, Vergallo A, Bonuccelli U, Zaccara G. Treatment of epilepsy in patients with Alzheimer’s disease. Expert Rev Neurother 2016; 17:309-318. [DOI: 10.1080/14737175.2017.1243469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Filippo Sean Giorgi
- Neurology Unit, Department of Clinical and Experimental Medicine, University of Pisa-Pisa University Hospital, Pisa, Italy
| | - Melania Guida
- Neurology Unit, Department of Clinical and Experimental Medicine, University of Pisa-Pisa University Hospital, Pisa, Italy
| | - Andrea Vergallo
- Neurology Unit, Department of Clinical and Experimental Medicine, University of Pisa-Pisa University Hospital, Pisa, Italy
| | - Ubaldo Bonuccelli
- Neurology Unit, Department of Clinical and Experimental Medicine, University of Pisa-Pisa University Hospital, Pisa, Italy
| | - Gaetano Zaccara
- Neurology Unit, Department of Medicine, Florence Health Authority, Firenze, Italy
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20
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Savitz J, Morris HM, Drevets WC. Neuroimaging Studies of Bipolar Depression: Therapeutic Implications. BIPOLAR DEPRESSION: MOLECULAR NEUROBIOLOGY, CLINICAL DIAGNOSIS, AND PHARMACOTHERAPY 2016. [DOI: 10.1007/978-3-319-31689-5_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Effects of isoflurane-induced anaesthesia on cognitive performance in a mouse model of Alzheimer's disease: A randomised trial in transgenic APP23 mice. Eur J Anaesthesiol 2015; 30:605-11. [PMID: 23274617 DOI: 10.1097/eja.0b013e32835b824b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Results from in-vitro experiments suggest that inhalational anaesthetics may have a detrimental effect on the course and incidence of Alzheimer's disease. However, case-control studies in humans show no negative impact of anaesthetics on the course of Alzheimer's disease. OBJECTIVE To test the hypothesis that 2 h of general anaesthesia with 1 MAC isoflurane changes learning abilities of young and old transgenic Alzheimer's mice (APP23 mice). DESIGN Randomised controlled double-blinded study in mice. SETTING Animal laboratory and operating theatre in the Klinik für Anästhesiologie, Technische Universität München, Germany ANIMALS Ninety-six male mice divided in four groups: young (4 months) APP23 mice and corresponding wild-type mice; old (14 to 16 months) APP23 and corresponding wild-type mice. INTERVENTION Mice were either anaesthetised for 2 h with 1 MAC isoflurane or sham-anaesthetised ('isoflurane' or 'control'). MAIN OUTCOME MEASURES Learning and locomotor activity during the following 8 days using the modified Hole Board Test for mice. Results are median (interquartile range) and median difference (95% confidence interval). RESULTS Young mice, [1.0 (1.3)] as assessed by the number of omission errors, learned better than old [1.8 (1.8); age: P = 0.004, median difference 0.5 (0.2 to 1.0)]. Anaesthetised animals [0.8 (1.5)] learned better than controls [1.6 (1.7); anaesthesia: P = 0.010, median difference 0.5 (0.1 to 0.9)]. This was accompanied by higher locomotor activity in young compared to old mice as assessed by number of line crossings per minute [10 (5) min(-1) vs. 7 (3) min(-1), P < 0.001, median difference 3 (2 to 4) min(-1)]. Anaesthesia and genotype Alzheimer's disease had no impact on locomotor activity. CONCLUSION Isoflurane may have protective, rather than detrimental, effects on cognition in Alzheimer's disease.
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Park SW, Lee JG, Seo MK, Cho HY, Lee CH, Lee JH, Lee BJ, Baek JH, Seol W, Kim YH. Effects of mood-stabilizing drugs on dendritic outgrowth and synaptic protein levels in primary hippocampal neurons. Bipolar Disord 2015; 17:278-90. [PMID: 25307211 DOI: 10.1111/bdi.12262] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 07/23/2014] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Mood-stabilizing drugs, such as lithium (Li) and valproate (VPA), are widely used for the treatment of bipolar disorder, a disease marked by recurrent episodes of mania and depression. Growing evidence suggests that Li exerts neurotrophic and neuroprotective effects, leading to an increase in neural plasticity. The present study investigated whether other mood-stabilizing drugs produce similar effects in primary hippocampal neurons. METHODS The effects of the mood-stabilizing drugs Li, VPA, carbamazepine (CBZ), and lamotrigine (LTG) on hippocampal dendritic outgrowth were examined. Western blotting analysis was used to measure the expression of synaptic proteins - that is, brain-derived neurotrophic factor (BDNF), postsynaptic density protein-95 (PSD-95), neuroligin 1 (NLG1), β-neurexin, and synaptophysin (SYP). To determine neuroprotective effects, we used a B27-deprivation cytotoxicity model which causes hippocampal cell death upon removal of B27 from the culture medium. RESULTS Li (0.5-2.0 mM), VPA (0.5-2.0 mM), CBZ (0.01-0.10 mM), and LTG (0.01-0.10 mM) significantly increased dendritic outgrowth. The neurotrophic effect of Li and VPA was blocked by inhibition of phosphatidylinositol 3-kinase, extracellular signal-regulated kinase, and protein kinase A signaling; the effects of CBZ and LTG were not affected by inhibition of these signaling pathways. Li, VPA, and CBZ prevented B27 deprivation-induced decreases in BDNF, PSD-95, NLG1, β-neurexin, and SYP levels, whereas LTG did not. CONCLUSIONS These results suggest that Li, VPA, CBZ, and LTG exert neurotrophic effects by promoting dendritic outgrowth; however, the mechanism of action differs. Furthermore, certain mood-stabilizing drugs may exert neuroprotective effects by enhancing synaptic protein levels against cytotoxicity in hippocampal cultures.
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Affiliation(s)
- Sung Woo Park
- Paik Institute for Clinical Research, Inje University, Busan, Korea; Department of Health Science and Technology, Graduate School of Inje University, Busan, Korea
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Kim TW. Drug repositioning approaches for the discovery of new therapeutics for Alzheimer's disease. Neurotherapeutics 2015; 12:132-42. [PMID: 25549849 PMCID: PMC4322062 DOI: 10.1007/s13311-014-0325-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and represents one of the highest unmet needs in medicine today. Drug development efforts for AD have been encumbered by largely unsuccessful clinical trials in the last decade. Drug repositioning, a process of discovering a new therapeutic use for existing drugs or drug candidates, is an attractive and timely drug development strategy especially for AD. Compared with traditional de novo drug development, time and cost are reduced as the safety and pharmacokinetic properties of most repositioning candidates have already been determined. A majority of drug repositioning efforts for AD have been based on positive clinical or epidemiological observations or in vivo efficacy found in mouse models of AD. More systematic, multidisciplinary approaches will further facilitate drug repositioning for AD. Some experimental approaches include unbiased phenotypic screening using the library of available drug collections in physiologically relevant model systems (e.g. stem cell-derived neurons or glial cells), computational prediction and selection approaches that leverage the accumulating data resulting from RNA expression profiles, and genome-wide association studies. This review will summarize several notable strategies and representative examples of drug repositioning for AD.
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Affiliation(s)
- Tae-Wan Kim
- Department of Pathology and Cell Biology, and Taub Institute of Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, 10032, USA,
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Mishra J, Chaudhary T, Kumar A. Rosiglitazone synergizes the neuroprotective effects of valproic acid against quinolinic acid-induced neurotoxicity in rats: targeting PPARγ and HDAC pathways. Neurotox Res 2014; 26:130-51. [PMID: 24566814 DOI: 10.1007/s12640-014-9458-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 02/01/2014] [Accepted: 02/04/2014] [Indexed: 12/15/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder which affects medium spiny GABAergic neurons mainly in the striatum. Oxidative damage, neuro-inflammation, apoptosis, protein aggregation, and signaling of neurotrophic factors are some of the common cellular pathways involved in HD. Quinolinic acid (QA) causes excitotoxicity by stimulating N-methyl-D-aspartate receptors via calcium overload leading to neurodegeneration. Neuroprotective potential of peroxisome proliferator activated receptor-γ (PPARγ) agonists and histone deacetylase (HDAC) inhibitors have been well documented in experimental models of neurodegenerative disorders; however, their exact mechanisms are not clear. Therefore, present study has been designed to explore possible neuroprotective mechanism of valproic acid (VPA) and its interaction with rosiglitazone against QA induced HD-like symptoms in rats. Single bilateral intrastriatal QA (200 nmol/2 μl saline) administration significantly caused motor incoordination, memory impairment, oxidative damage, mitochondrial dysfunction (complex I, II, II and IV), cellular alterations [tumor necrosis factor-alpha (TNF-α), caspase-3, brain derived neurotrophic factor, acetylcholinesterase], and striatal neurodegeneration as compared to sham group. Treatment with rosiglitazone (5, 10 mg/kg) and VPA (100, 200 mg/kg) for 21 days significantly attenuated these behavioral, biochemical, and cellular alterations as compared to control (QA 200 nmol) group. However, VPA (100 mg/kg) treatment in combination with rosiglitazone (5 mg/kg) for 21 days synergized their neuroprotective effect, which was significant as compared to their effects per se in QA-treated animals. The present study provides an evidence of possible interplay of PPARγ agonists and HDAC inhibitors as a novel therapeutic strategy in the management of HD.
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Affiliation(s)
- Jitendriya Mishra
- Pharmacology Division, UGC Centre of Advanced Study (UGC-CAS), University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, 160014, India
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Appleby BS, Nacopoulos D, Milano N, Zhong K, Cummings JL. A review: treatment of Alzheimer's disease discovered in repurposed agents. Dement Geriatr Cogn Disord 2013; 35:1-22. [PMID: 23307039 DOI: 10.1159/000345791] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/13/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND/AIMS Many compounds that have already been approved for alternate diagnoses have been studied in relation to Alzheimer's disease (AD). The purpose of this review is to summarize these studies and discuss the rationale and benefits of repurposing drugs for AD treatment. METHODS Studies of drugs related to AD treatment that were relevant to a disease-modifying mechanism of action (MOA) and are already approved by the Food and Drug Administration for non-AD diagnoses were collected from PubMed. RESULTS Many drugs already approved for the treatment of other diseases have been studied in relation to AD treatment. Numerous drugs with known toxicity profiles have the potential to be repurposed as a treatment for AD. CONCLUSION Known MOA, toxicology, and pharmacodynamic profiles would accelerate the process and increase the odds of finding a more timely disease-modifying treatment for AD.
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Affiliation(s)
- Brian S Appleby
- Cleveland Clinic Lou Ruvo Center for Brain Health, Cleveland, OH, USA
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What's hAPPening at synapses? The role of amyloid β-protein precursor and β-amyloid in neurological disorders. Mol Psychiatry 2013; 18:425-34. [PMID: 22925831 DOI: 10.1038/mp.2012.122] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Accumulating evidence suggests that dysregulated levels of amyloid β-protein precursor (APP) and its catabolites contribute to the impaired synaptic plasticity and seizure incidence observed in several neurological disorders, including Alzheimer's disease, fragile X syndrome, Down's syndrome, autism, epilepsy and Parkinson's disease as well as in brain injury. This review article summarizes what is known regarding the synaptic synthesis, processing and function of APP and amyloid-beta (Aβ), as well as discusses how these proteins could contribute to the altered synaptic plasticity and pathology of the aforementioned disorders. In addition, APP and its proteolytic fragments are emerging as biomarkers for neurological health, and pharmacological interventions that modulate their levels, such as secretase inhibitors, passive immunotherapy against Aβ and mGluR5 antagonists, are reviewed.
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Tariot PN, Schneider LS, Cummings J, Thomas RG, Raman R, Jakimovich LJ, Loy R, Bartocci B, Fleisher A, Ismail MS, Porsteinsson A, Weiner M, Jack CR, Thal L, Aisen PS. Chronic divalproex sodium to attenuate agitation and clinical progression of Alzheimer disease. ACTA ACUST UNITED AC 2011; 68:853-61. [PMID: 21810649 DOI: 10.1001/archgenpsychiatry.2011.72] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Agitation and psychosis are common in Alzheimer disease and cause considerable morbidity. We attempted to delay or to prevent agitation and psychosis with the use of divalproex sodium (valproate). OBJECTIVE To determine whether treatment with valproate could delay or prevent emergence of agitation or psychosis. DESIGN, SETTING, AND PATIENTS A multicenter, randomized, double-blind, placebo-controlled trial of flexible-dose valproate in 313 (of 513 screened) individuals with moderate Alzheimer disease who had not yet experienced agitation or psychosis. The study was conducted from November 1, 2005, through March 31, 2009, at 46 sites in the United States. INTERVENTION Participants were randomly assigned to valproate treatment at a target dose of 10 to 12 mg per kilogram of body weight per day or identical-appearing placebo for 24 months followed by a 2-month period of single-blind placebo treatment. MAIN OUTCOME MEASURE Time to emergence of clinically significant agitation or psychosis. RESULTS A total of 122 participants (59 receiving valproate and 63 receiving placebo) completed 24 months of treatment while taking study medication; 42 (27 receiving valproate and 15 receiving placebo) reached 24 months having discontinued study medication; 150 reached month 26. There was no difference between groups in time to emergence of agitation or psychosis (Cox proportional hazard ratio, 0.96; P = .88). There was no difference between groups in change on any secondary outcome. The valproate group had higher rates of somnolence, gait disturbance, tremor, diarrhea, and weakness. Eighty-eight participants underwent magnetic resonance imaging scans at baseline and 12 months; the valproate group showed greater loss in hippocampal and whole-brain volume, accompanied by greater ventricular expansion (P < .001). CONCLUSION Valproate treatment did not delay emergence of agitation or psychosis or slow cognitive or functional decline in patients with moderate Alzheimer disease and was associated with significant toxic effects.
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Affiliation(s)
- Pierre N Tariot
- Banner Alzheimer's Institute, 901 E Willetta St., Phoenix, AZ 85006, USA.
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Fleisher AS, Truran D, Mai JT, Langbaum JBS, Aisen PS, Cummings JL, Jack CR, Weiner MW, Thomas RG, Schneider LS, Tariot PN. Chronic divalproex sodium use and brain atrophy in Alzheimer disease. Neurology 2011; 77:1263-71. [PMID: 21917762 DOI: 10.1212/wnl.0b013e318230a16c] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE We evaluated the effect of the divalproex sodium formulation of valproic acid on brain volumes using MRI in people with mild to moderate Alzheimer disease (AD) and assessed for changes associated with behavioral and cognitive effects. METHODS Eighty-nine of 313 participants randomized to divalproex or placebo in a 24-month, parallel-group trial received MRI scans at baseline and 12 months. Interval MRI annual percent changes in whole brain, ventricular, and hippocampal volumes were the primary outcomes of interest. Change from baseline in clinical outcomes was assessed at 6-month intervals. RESULTS There were no baseline differences between active treatment and placebo groups in age, education, brain volumes, clinical rating scores, or APOE ε4 carrier status. The group treated with divalproex showed a greater rate of decline in left and right hippocampal and brain volumes (-10.9% and -12.4% vs -5.6% and -6.3%, and -3.5% vs -1.4%, respectively), and a greater rate of ventricular expansion (24.5% vs 9.9%) (p < 0.001). Mini-Mental State Examination scores showed a more rapid decline with divalproex through month 12 (placebo = -2.0 ± 4.3, divalproex = -3.9 ± 4.0) (p = 0.037), although there were no changes on other cognitive, behavioral, or functional ratings at 12 and 24 months. CONCLUSIONS Divalproex treatment was associated with accelerated brain volume loss over 1 year and perhaps with greater cognitive impairment. The long-term clinical effects of these changes are not known.
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Affiliation(s)
- A S Fleisher
- Banner Alzheimer's Institute, 901 E Willetta Street, Phoenix, AZ 85006, USA.
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Liu D, Pitta M, Lee JH, Ray B, Lahiri DK, Furukawa K, Mughal M, Jiang H, Villarreal J, Cutler RG, Greig NH, Mattson MP. The KATP channel activator diazoxide ameliorates amyloid-β and tau pathologies and improves memory in the 3xTgAD mouse model of Alzheimer's disease. J Alzheimers Dis 2011; 22:443-57. [PMID: 20847430 DOI: 10.3233/jad-2010-101017] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Compromised cellular energy metabolism, cerebral hypoperfusion, and neuronal calcium dysregulation are involved in the pathological process of Alzheimer's disease (AD). ATP-sensitive potassium (KATP) channels in plasma membrane and inner mitochondrial membrane play important roles in modulating neuronal excitability, cell survival, and cerebral vascular tone. To investigate the therapeutic potential of drugs that activate KATP channels in AD, we first characterized the effects of the KATP channel opener diazoxide on cultured neurons, and then determined its ability to modify the disease process in the 3xTgAD mouse model of AD. Plasma and mitochondrial membrane potentials, cell excitability, intracellular Ca2+ levels and bioenergetics were measured in cultured cerebral cortical neurons exposed to diazoxide. Diazoxide hyperpolarized neurons, reduced the frequency of action potentials, attenuated Ca2+ influx through NMDA receptor channels, and reduced oxidative stress. 3xTgAD mice treated with diazoxide for 8 months exhibited improved performance in a learning and memory test, reduced levels of anxiety, decreased accumulation of Aβ oligomers and hyperphosphorylated tau in the cortex and hippocampus, and increased cerebral blood flow. Our findings show that diazoxide can ameliorate molecular, cytopathological, and behavioral alterations in a mouse model of AD suggesting a therapeutic potential for drugs that activate KATP channels in the treatment of AD.
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Affiliation(s)
- Dong Liu
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
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A meta-analysis of mood stabilizers for Alzheimer's disease. ACTA ACUST UNITED AC 2010; 30:652-8. [PMID: 21063851 DOI: 10.1007/s11596-010-0559-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Indexed: 10/18/2022]
Abstract
The objective of this study was to assess the clinical evidence for or against mood stabilizers as a treatment for Alzheimer's disease (AD). We searched 5 databases from their inception to January 2010. Five randomized clinical trials of mood stabilizers to treat human patients suffering from AD were included. These trials assessed the effectiveness of mood stabilizers as an adjunct treatment to conventional anti-dementia drugs on behavioral and psychological symptoms, especially on agitation. Methodological quality was assessed using the Jadad score. The results suggested a significant effect in favor of placebo on the Mini-Mental Status Examination [n=270, weight mean difference (WMD), -0.89; 95% confidence intervals (CIs) -1.69 to -0.09, P=0.03] and on the Neuropsychiatric Inventory total (NPI total) (n=51, WMD, 3.71; 95% CIs 0.15 to 7.26, P=0.04). There were no significant differences in change scores on total Brief Psychiatric Rating Scale (BPRS total), NPI/BPRS agitation, Cohen-Mansfield Agitation Inventory total and Physical Self Maintenance Scale between mood stabilizers and placebo. Only one of these studies was free of methodological limitations (Jadad score=5). In conclusion, based on the existing evidence, mood stabilizers are ineffective or even harmful as a treatment for AD.
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Creed MC, Milgram NW. Amyloid-modifying therapies for Alzheimer's disease: therapeutic progress and its implications. AGE (DORDRECHT, NETHERLANDS) 2010; 32:365-84. [PMID: 20640545 PMCID: PMC2926857 DOI: 10.1007/s11357-010-9142-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 03/25/2010] [Indexed: 05/03/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia, affecting an estimated 4.8 million people in North America. For the past decade, the amyloid cascade hypothesis has dominated the field of AD research. This theory posits that the deposition of amyloid-beta protein (Abeta) in the brain is the key pathologic event in AD, which induces a series of neuropathological changes that manifest as cognitive decline and eventual dementia. Based on this theory, interventions that reduce Abeta burden in the brain would be expected to alleviate both the neuropathological changes and dementia, which characterize AD. Several diverse pharmacological strategies have been developed to accomplish this. These include inhibiting the formation of Abeta, preventing the aggregation of Abeta into insoluble aggregates, preventing the entry of Abeta into the brain from the periphery and enhancing the clearance of Abeta from the central nervous system. To date, no amyloid-modifying therapy has yet been successful in phase 3 clinical trials; however, several trials are currently underway. This article provides a review of the status of amyloid-modifying therapies and the implications for the amyloid cascade hypothesis.
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Affiliation(s)
- Meaghan C Creed
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
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Kim DH, Yoon BH, Jung WY, Kim JM, Park SJ, Park DH, Huh Y, Park C, Cheong JH, Lee KT, Shin CY, Ryu JH. Sinapic acid attenuates kainic acid-induced hippocampal neuronal damage in mice. Neuropharmacology 2010; 59:20-30. [PMID: 20363233 DOI: 10.1016/j.neuropharm.2010.03.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 01/27/2010] [Accepted: 03/19/2010] [Indexed: 10/19/2022]
Abstract
Excitotoxin induces neurodegeneration via glutamatergic activation or oxidative stress, which means that the blockade of glutamate receptors and the scavenging of free radicals are potential therapeutic targets in neurodegenerative diseases. Sinapic acid (SA) has a GABA(A) receptor agonistic property and free radical scavenging activity. We investigated the neuroprotective effects of SA on kainic acid (KA)-induced hippocampal brain damage in mice. SA (10 mg/kg) by oral administration has an anticonvulsant effect on KA-induced seizure-like behavior. Moreover, SA (10 mg/kg) significantly attenuated KA-induced neuronal cell death in the CA1 and CA3 hippocampal regions when administered as late as 6 h after KA. In addition, flumazenil, a GABA(A) antagonist, blocked the effect of SA administered immediately after KA but not the effect of SA administered 6 h after KA. This late protective effect of SA was accompanied by reduced levels of reactive gliosis, inducible nitric oxide synthase expression, and nitrotyrosine formation in the hippocampus. In the passive avoidance task, KA-induced memory impairments were ameliorated by SA. These results suggest that the potential therapeutic effect of SA is due to its attenuation of KA-induced neuronal damage in the brain via its anti-convulsive activity through GABA(A) receptor activation and radical scavenging activity.
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Affiliation(s)
- Dong Hyun Kim
- Department of Life and Nanopharmaceutical Sciences, Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul, Republic of Korea
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España J, Giménez-Llort L, Valero J, Miñano A, Rábano A, Rodriguez-Alvarez J, LaFerla FM, Saura CA. Intraneuronal beta-amyloid accumulation in the amygdala enhances fear and anxiety in Alzheimer's disease transgenic mice. Biol Psychiatry 2010; 67:513-21. [PMID: 19664757 DOI: 10.1016/j.biopsych.2009.06.015] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 06/18/2009] [Accepted: 06/19/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by progressive memory decline and neuropsychiatric symptoms. Despite common emotional symptoms in AD such as anxiety and fear are associated with a more rapid cognitive decline, the pathological mechanisms involved in these behavioral changes remain largely elusive. In this study, we examined the pathological mechanisms of emotional behavior in well-established AD transgenic mice expressing human mutant beta-amyloid (Abeta) precursor protein (APP(Ind) and APP(Sw,Ind)) and tau (3xTg-AD). METHODS We evaluated unconditioned and conditioned fear-induced freezing behavior and spatial memory in APP(Ind), APP(Sw,Ind), and 3xTg-AD transgenic mice. The Abeta and tau pathologies and signaling pathways involved in emotional processing were studied by immunohistochemistry and immunoblotting analyses. RESULTS The APP(Ind)/APP(Sw,Ind) and 3xTg-AD transgenic mice displayed at early ages enhanced innate and conditioned fear symptoms and spatial memory deficits coinciding with enhanced accumulation of Abeta in gamma-aminobutyric acid (GABA)ergic and glutamatergic neurons, respectively, of the basolateral amygdala (BLA). Similarly, the number of neurons with intraneuronal Abeta40 and Abeta42 was significantly increased in the BLA of human AD brains. Fear responses might reflect an influence of anxiety, because the anxiolytic compounds valproate, diazepam, and buspirone reduced efficiently unconditioned and conditioned fear responses in APP transgenic mice. In addition, phosphorylation of extracellular signal-regulated kinase (ERK)1/2, which is critical for acquisition and consolidation of fear conditioning, was increased in the amygdala of APP transgenic mice after cued conditioning. CONCLUSIONS We propose a deleterious role of intraneuronal Abeta on amygdala-dependent emotional responses by affecting the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway.
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Affiliation(s)
- Judit España
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Valproic acid as a promising agent to combat Alzheimer's disease. Brain Res Bull 2010; 81:3-6. [DOI: 10.1016/j.brainresbull.2009.09.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 09/04/2009] [Accepted: 09/07/2009] [Indexed: 01/03/2023]
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Amygdala volume in depressed patients with bipolar disorder assessed using high resolution 3T MRI: the impact of medication. Neuroimage 2009; 49:2966-76. [PMID: 19931399 DOI: 10.1016/j.neuroimage.2009.11.025] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 11/06/2009] [Accepted: 11/11/2009] [Indexed: 12/24/2022] Open
Abstract
MRI-based reports of both abnormally increased and decreased amygdala volume in bipolar disorder (BD) have surfaced in the literature. Two major methodological weaknesses characterizing extant studies are treatment with medication and inaccurate segmentation of the amygdala due to limitations in spatial and tissue contrast resolution. Here, we acquired high-resolution images (voxel size=0.55 x 0.55 x 0.60 mm) using a GE 3T MRI scanner, and a pulse sequence optimized for tissue contrast resolution. The amygdala was manually segmented by one rater blind to diagnosis, using coronal images. Eighteen unmedicated (mean medication-free period 11+/-10 months) BD subjects were age and gender matched with 18 healthy controls, and 17 medicated (lithium or divalproex) subjects were matched to 17 different controls. The unmedicated BD patients displayed smaller left and right amygdala volumes than their matched control group (p<0.01). Conversely, the BD subjects undergoing medication treatment showed a trend towards greater amygdala volumes than their matched HC sample (p=0.051). Right and left amygdala volumes were larger (p<0.05) or trended larger, respectively, in the medicated BD sample compared with the unmedicated BD sample. The two control groups did not differ from each other in either left or right amygdala volume. BD patients treated with lithium have displayed increased gray matter volume of the cortex and hippocampus relative to untreated BD subjects in previous studies. Here we extend these results to the amygdala. We raise the possibility that neuroplastic changes in the amygdala associated with BD are moderated by some mood stabilizing medications.
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Trends in the molecular pathogenesis and clinical therapeutics of common neurodegenerative disorders. Int J Mol Sci 2009; 10:2510-2557. [PMID: 19582217 PMCID: PMC2705504 DOI: 10.3390/ijms10062510] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 04/28/2009] [Accepted: 05/05/2009] [Indexed: 12/11/2022] Open
Abstract
The term neurodegenerative disorders, encompasses a variety of underlying conditions, sporadic and/or familial and are characterized by the persistent loss of neuronal subtypes. These disorders can disrupt molecular pathways, synapses, neuronal subpopulations and local circuits in specific brain regions, as well as higher-order neural networks. Abnormal network activities may result in a vicious cycle, further impairing the integrity and functions of neurons and synapses, for example, through aberrant excitation or inhibition. The most common neurodegenerative disorders are Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis and Huntington’s disease. The molecular features of these disorders have been extensively researched and various unique neurotherapeutic interventions have been developed. However, there is an enormous coercion to integrate the existing knowledge in order to intensify the reliability with which neurodegenerative disorders can be diagnosed and treated. The objective of this review article is therefore to assimilate these disorders’ in terms of their neuropathology, neurogenetics, etiology, trends in pharmacological treatment, clinical management, and the use of innovative neurotherapeutic interventions.
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Bipolar and major depressive disorder: neuroimaging the developmental-degenerative divide. Neurosci Biobehav Rev 2009; 33:699-771. [PMID: 19428491 DOI: 10.1016/j.neubiorev.2009.01.004] [Citation(s) in RCA: 361] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/14/2009] [Indexed: 01/30/2023]
Abstract
Both major depressive disorder and bipolar disorder are the subject of a voluminous imaging and genetics literature. Here, we attempt a comprehensive review of MRI and metabolic PET studies conducted to date on these two disorders, and interpret our findings from the perspective of developmental and degenerative models of illness. Elevated activity and volume loss of the hippocampus, orbital and ventral prefrontal cortex are recurrent themes in the literature. In contrast, dorsal aspects of the PFC tend to display hypometabolism. Ventriculomegaly and white matter hyperintensities are intimately associated with depression in elderly populations and likely have a vascular origin. Important confounding influences are medication, phenotypic and genetic heterogeneity, and technological limitations. We suggest that environmental stress and genetic risk variants interact with each other in a complex manner to alter neural circuitry and precipitate illness. Imaging genetic approaches hold out promise for advancing our understanding of affective illness.
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Yaari R, Kumar S, Tariot PN. Non-cholinergic drug development for Alzheimer's disease. Expert Opin Drug Discov 2008; 3:745-60. [DOI: 10.1517/17460441.3.7.745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Ng B, Camacho A, Lara DR, Brunstein MG, Pinto OC, Akiskal HS. A case series on the hypothesized connection between dementia and bipolar spectrum disorders: bipolar type VI? J Affect Disord 2008; 107:307-15. [PMID: 17889374 DOI: 10.1016/j.jad.2007.08.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Accepted: 08/28/2007] [Indexed: 11/21/2022]
Abstract
BACKGROUND The concept of bipolar spectrum disorders has opened therapeutic opportunities for patients with atypical and complex affective conditions. The literature has recently described several commonalities in pathophysiological processes of bipolar disorders and dementia. However, this connection has been insufficiently appreciated at the clinical level, in part because affective dysregulation in the elderly and, particularly in the dementia setting, is typically attributed either to secondary depressive states or otherwise relegated to a neurologically understandable behavioral complication resulting from cerebral disease. METHODS We selected a case series of 10 elderly patients with late-onset mood and related behavioral symptomatology and cognitive decline without past history of clear-cut bipolar disorder. Clinical features, temperament, cognition, family history and pharmacological response were assessed to identify prototypical patients to illustrate the complexities of the dementia-bipolar interface. RESULTS Mixed and depressive mood symptoms were most commonly observed and all patients had been premorbidly of hyperthymic, cyclothymic and/or irritable temperaments. Most patients had a family history of bipolar disorder or disorders related to the bipolar diathesis. Symptoms were often refractory to or aggravated by antidepressants and acetylcholinesterase inhibitors, whereas mood stabilizers and/or atypical antipsychotics were beneficial, promoting behavioral improvement in all treated patients and marked cognitive recovery in five. LIMITATIONS Case series with retrospective methodology. CONCLUSION AND CLINICAL IMPLICATIONS Patients with cognitive decline and frequent mood lability might be manifesting a late-onset bipolar spectrum disorder, which we posit as type VI. We further posit that dementia and/or other biopsychosocial challenges associated with aging might release latent bipolarity in such individuals. Antidepressants, even drugs targeting dementia, might aggravate the behavioral dysregulation in these patients. Evaluation of premorbid temperament and/or family history of bipolarity and related disorders might help in broadening the clinical and biological understanding of such patients, providing a rationale for better customized treatment along the lines of mood stabilization and avoidance of antidepressants.
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Affiliation(s)
- Bernardo Ng
- International Mood Center, and Department of Psychiatry, University of California, San Diego, CA, USA.
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Palop JJ, Chin J, Roberson ED, Wang J, Thwin MT, Bien-Ly N, Yoo J, Ho KO, Yu GQ, Kreitzer A, Finkbeiner S, Noebels JL, Mucke L. Aberrant excitatory neuronal activity and compensatory remodeling of inhibitory hippocampal circuits in mouse models of Alzheimer's disease. Neuron 2007; 55:697-711. [PMID: 17785178 PMCID: PMC8055171 DOI: 10.1016/j.neuron.2007.07.025] [Citation(s) in RCA: 1194] [Impact Index Per Article: 70.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 05/11/2007] [Accepted: 07/18/2007] [Indexed: 11/27/2022]
Abstract
Neural network dysfunction may play an important role in Alzheimer's disease (AD). Neuronal circuits vulnerable to AD are also affected in human amyloid precursor protein (hAPP) transgenic mice. hAPP mice with high levels of amyloid-beta peptides in the brain develop AD-like abnormalities, including cognitive deficits and depletions of calcium-related proteins in the dentate gyrus, a region critically involved in learning and memory. Here, we report that hAPP mice have spontaneous nonconvulsive seizure activity in cortical and hippocampal networks, which is associated with GABAergic sprouting, enhanced synaptic inhibition, and synaptic plasticity deficits in the dentate gyrus. Many Abeta-induced neuronal alterations could be simulated in nontransgenic mice by excitotoxin challenge and prevented in hAPP mice by blocking overexcitation. Aberrant increases in network excitability and compensatory inhibitory mechanisms in the hippocampus may contribute to Abeta-induced neurological deficits in hAPP mice and, possibly, also in humans with AD.
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Affiliation(s)
- Jorge J. Palop
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Correspondence: or
| | - Jeannie Chin
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Erik D. Roberson
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jun Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Myo T. Thwin
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Nga Bien-Ly
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Jong Yoo
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kaitlyn O. Ho
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Anatol Kreitzer
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jeffrey L. Noebels
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
- Correspondence: or
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41
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Basselin M, Villacreses NE, Chen M, Bell JM, Rapoport SI. Chronic carbamazepine administration reduces N-methyl-D-aspartate receptor-initiated signaling via arachidonic acid in rat brain. Biol Psychiatry 2007; 62:934-43. [PMID: 17628508 PMCID: PMC2131715 DOI: 10.1016/j.biopsych.2007.04.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 04/11/2007] [Accepted: 04/11/2007] [Indexed: 01/16/2023]
Abstract
BACKGROUND Lithium and carbamazepine (CBZ) are used to treat mania in bipolar disorder. When given chronically to rats, both agents reduce arachidonic acid (AA) turnover in brain phospholipids and downstream AA metabolism. Lithium in rats also attenuates brain N-methyl-D-aspartic acid receptor (NMDAR) signaling via AA. We hypothesized that, like chronic lithium, chronic CBZ administration to rats would reduce NMDAR-mediated signaling via AA. METHODS We used our fatty acid method with quantitative autoradiography to image the regional brain incorporation coefficient k* of AA, a marker of AA signaling, in unanesthetized rats that had been given 25 mg/kg/day I.P. CBZ or vehicle for 30 days, then injected with NMDA (25 mg/kg I.P.) or saline. We also measured brain concentrations of two AA metabolites, prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)). RESULTS In chronic vehicle-treated rats, NMDA compared with saline increased k* significantly in 69 of 82 brain regions examined, but did not change k* significantly in any region in CBZ-treated rats. In vehicle- but not CBZ-treated rats, NMDA also increased brain concentrations of PGE(2) and TXB(2). CONCLUSIONS Chronic CBZ administration to rats blocks increments in the AA signal k*, and in PGE(2) and TXB(2) concentrations that are produced by NMDA in vehicle-treated rats. The clinical action of antimanic drugs might involve inhibition of brain NMDAR-mediated signaling involving AA and its metabolites.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Crouch PJ, Harding SME, White AR, Camakaris J, Bush AI, Masters CL. Mechanisms of A beta mediated neurodegeneration in Alzheimer's disease. Int J Biochem Cell Biol 2007; 40:181-98. [PMID: 17804276 DOI: 10.1016/j.biocel.2007.07.013] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/30/2007] [Accepted: 07/24/2007] [Indexed: 11/24/2022]
Abstract
Development of a comprehensive therapeutic treatment for the neurodegenerative Alzheimer's disease (AD) is limited by our understanding of the underlying biochemical mechanisms that drive neuronal failure. Numerous dysfunctional mechanisms have been described in AD, ranging from protein aggregation and oxidative stress to biometal dyshomeostasis and mitochondrial failure. In this review we discuss the critical role of amyloid-beta (A beta) in some of these potential mechanisms of neurodegeneration. The 39-43 amino acid A beta peptide has attracted intense research focus since it was identified as a major constituent of the amyloid deposits that characterise the AD brain, and it is now widely recognised as central to the development of AD. Familial forms of AD involve mutations that lead directly to altered A beta production from the amyloid-beta A4 precursor protein, and the degree of AD severity correlates with specific pools of A beta within the brain. A beta contributes directly to oxidative stress, mitochondrial dysfunction, impaired synaptic transmission, the disruption of membrane integrity, and impaired axonal transport. Further study of the mechanisms of A beta mediated neurodegeneration will considerably improve our understanding of AD, and may provide fundamental insights needed for the development of more effective therapeutic strategies.
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Affiliation(s)
- Peter J Crouch
- Department of Pathology, The University of Melbourne, Victoria 3010, Australia.
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43
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Abstract
Patients with Alzheimer's disease or other neurodegenerative disorders show remarkable fluctuations in neurological functions, even during the same day. These fluctuations cannot be caused by sudden loss or gain of nerve cells. Instead, it is likely that they reflect variations in the activity of neural networks and, perhaps, chronic intoxication by abnormal proteins that the brain is temporarily able to overcome. These ideas have far-reaching therapeutic implications.
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Affiliation(s)
- Jorge J Palop
- Gladstone Institute of Neurological Disease and Department of Neurology, University of California, San Francisco, California 94158, USA
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44
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Krebs M, Leopold K, Hinzpeter A, Schaefer M. Neuroprotective agents in schizophrenia and affective disorders. Expert Opin Pharmacother 2006; 7:837-48. [PMID: 16634707 DOI: 10.1517/14656566.7.7.837] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
With the exception of dementia, the use of neuroprotective agents in psychiatric disorders is not yet well established. However, recent data from brain imaging studies and clinical trials support the view that neurodegenerative mechanisms may play a role in the pathophysiology of schizophrenia and affective disorders. Further evidence for the use of neuroprotective agents can be drawn from the findings that second-generation antipsychotics, mood stabilizers and antidepressants have been shown to have neuroprotective effects in vitro and in vivo. Neuroprotective agents as add-on therapies (e.g., modafinil, erythropoietin, glycine, D-serine, memantine and celecoxib) are currently being evaluated in schizophrenia and related disorders. This paper reviews the current options for neuroprotective treatment approaches focusing on schizophrenia and affective disorders.
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Affiliation(s)
- Michael Krebs
- Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Campus Charité Mitte, Schumannstr. 20/21, D-10117 Berlin, Germany.
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Lee BY, Ban JY, Seong YH. Chronic stimulation of GABAA receptor with muscimol reduces amyloid β protein (25–35)-induced neurotoxicity in cultured rat cortical cells. Neurosci Res 2005; 52:347-56. [PMID: 15896866 DOI: 10.1016/j.neures.2005.04.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 03/28/2005] [Accepted: 04/15/2005] [Indexed: 12/20/2022]
Abstract
The present study was performed to examine how the stimulation of gamma-aminobutyric acid (GABA) receptor affects amyloid beta protein (25-35) (Abeta (25-35)), a synthetic 25-35 amyloid peptide, -induced neurotoxicity using cultured rat cortical neurons. Abeta (25-35) produced a concentration-dependent reduction of cell viability, which was significantly reduced by (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine (MK-801), an N-methyl-d-aspartate (NMDA) receptor antagonist, verapamil, an L-type Ca(2+) channel blocker, and N(G)-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase inhibitor. Pretreatment with muscimol, a GABAA receptor agonist, over a concentration range of 0.1-10microM 24h before the treatment with 10microM Abeta (25-35) showed concentration-dependent inhibition on the Abeta (25-35)-induced neuronal apoptotic death. However, baclofen (1 and 10microM), a GABAB receptor agonist, failed to inhibit the Abeta (25-35)-induced neuronal death. In addition, pretreatment with muscimol (1microM) for 24h inhibited the Abeta (25-35) (10microM)-induced elevation of cytosolic Ca(2+) concentration ([Ca(2+)]c) and glutamate release, generation of reactive oxygen species (ROS), and caspase-3 activity in cultured neurons. These neuroprotective effects of muscimol (1microM) were completely blocked by the simultaneous treatment with 10microM bicuculline, a GABAA receptor antagonist, indicating that the protective effects of muscimol were due to GABAA receptor stimulation. When, however, treated just 15min before the treatment with Abeta (25-35), muscimol (1microM) did not show any protective effect against Abeta (25-35) (10microM)-induced neurotoxicity in cultured neurons. These results suggest that the chronic activation of GABAA receptor may ameliorate Abeta-induced neurotoxicity by interfering with the increase of [Ca(2+)]c, and then by inhibiting glutamate release, generation of ROS and caspase-3 activity.
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Affiliation(s)
- Bo Young Lee
- College of Veterinary Medicine and Research Institute of Herbal Medicine, Chungbuk National University, 12 Gaesin-dong, Heungduk-Gu, Cheongju, Chungbuk 361-763, Republic of Korea
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46
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Abstract
In this article, we discuss and highlight some of the potential neurochemical underpinnings of bipolar disorder (BD) and epilepsy. Some similarities are found in both disorders, such as the episodic course of the illnesses, the possible mechanism of kindling, and the efficacy of some antiepileptic drugs (AEDs) in treatment, all pointing to a common underlying pathophysiology. Common mechanisms at the level of ion channels might include the antikindling and the calcium-antagonistic and potassium outward current-modulating properties of AEDs. However, future research on intracellular mechanisms might become decisive for a better understanding of the similarities between the disorders.
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Affiliation(s)
- Benedikt Amann
- Department of Psychiatry, University LMU Munich, Munich, Germany.
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47
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Gould TD, Quiroz JA, Singh J, Zarate CA, Manji HK. Emerging experimental therapeutics for bipolar disorder: insights from the molecular and cellular actions of current mood stabilizers. Mol Psychiatry 2004; 9:734-55. [PMID: 15136794 DOI: 10.1038/sj.mp.4001518] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bipolar disorder afflicts approximately 1-3% of both men and women, and is coincident with major economic, societal, medical, and interpersonal consequences. Current mediations used for its treatment are associated with variable rates of efficacy and often intolerable side effects. While preclinical and clinical knowledge in the neurosciences has expanded at a tremendous rate, recent years have seen no major breakthroughs in the development of novel types of treatment for bipolar disorder. We review here approaches to develop novel treatments specifically for bipolar disorder. Deliberate (ie not by serendipity) treatments may come from one of two general mechanisms: (1) Understanding the mechanism of action of current medications and thereafter designing novel drugs that mimics these mechanism(s); (2) Basing medication development upon the hypothetical or proven underlying pathophysiology of bipolar disorder. In this review, we focus upon the first approach. Molecular and cellular targets of current mood stabilizers include lithium inhibitable enzymes where lithium competes for a magnesium binding site (inositol monophosphatase, inositol polyphosphate 1-phosphatase, glycogen synthase kinase-3 (GSK-3), fructose 1,6-bisphosphatase, bisphosphate nucleotidase, phosphoglucomutase), valproate inhibitable enzymes (succinate semialdehyde dehydrogenase, succinate semialdehyde reductase, histone deacetylase), targets of carbamazepine (sodium channels, adenosine receptors, adenylate cyclase), and signaling pathways regulated by multiple drugs of different classes (phosphoinositol/protein kinase C, cyclic AMP, arachidonic acid, neurotrophic pathways). While the task of developing novel medications for bipolar disorder is truly daunting, we are hopeful that understanding the mechanism of action of current mood stabilizers will ultimately lead clinical trials with more specific medications and thus better treatments those who suffer from this devastating illness.
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Affiliation(s)
- T D Gould
- Laboratory of Molecular Pathophysiology, National Institute of Mental Health, Bethesda, MD 20892, USA
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48
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Louzada PR, Paula Lima AC, Mendonca-Silva DL, Noël F, De Mello FG, Ferreira ST. Taurine prevents the neurotoxicity of beta-amyloid and glutamate receptor agonists: activation of GABA receptors and possible implications for Alzheimer's disease and other neurological disorders. FASEB J 2004; 18:511-8. [PMID: 15003996 DOI: 10.1096/fj.03-0739com] [Citation(s) in RCA: 183] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Alzheimer's disease (AD) and several other neurological disorders have been linked to the overactivation of glutamatergic transmission and excitotoxicity as a common pathway of neuronal injury. The beta-amyloid peptide (Abeta) is centrally related to the pathogenesis of AD, and previous reports have demonstrated that the blockade of glutamate receptors prevents Abeta-induced neuronal death. We show that taurine, a beta-amino acid found at high concentrations in the brain, protects chick retinal neurons in culture against the neurotoxicity of Abeta and glutamate receptor agonists. The protective effect of taurine is not mediated by interaction with glutamate receptors, as demonstrated by binding studies using radiolabeled glutamate receptor ligands. The neuroprotective action of taurine is blocked by picrotoxin, an antagonist of GABA(A) receptors. GABA and the GABA(A) receptor agonists phenobarbital and melatonin also protect neurons against Abeta-induced neurotoxicity. These results suggest that activation of GABA receptors decreases neuronal vulnerability to excitotoxic damage and that pharmacological manipulation of the excitatory and inhibitory neurotransmitter tonus may protect neurons against a variety of insults. GABAergic transmission may represent a promising target for the treatment of AD and other neurological disorders in which excitotoxicity plays a relevant role.
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Affiliation(s)
- Paulo Roberto Louzada
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brasil
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Ren M, Leng Y, Jeong M, Leeds PR, Chuang DM. Valproic acid reduces brain damage induced by transient focal cerebral ischemia in rats: potential roles of histone deacetylase inhibition and heat shock protein induction. J Neurochem 2004; 89:1358-67. [PMID: 15189338 DOI: 10.1111/j.1471-4159.2004.02406.x] [Citation(s) in RCA: 297] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Growing evidence from in vitro studies supports that valproic acid (VPA), an anti-convulsant and mood-stabilizing drug, has neuroprotective effects. The present study investigated whether VPA reduces brain damage and improves functional outcome in a transient focal cerebral ischemia model of rats. Subcutaneous injection of VPA (300 mg/kg) immediately after ischemia followed by repeated injections every 12 h, was found to markedly decrease infarct size and reduce ischemia-induced neurological deficit scores measured at 24 and 48 h after ischemic onset. VPA treatment also suppressed ischemia-induced neuronal caspase-3 activation in the cerebral cortex. VPA treatments resulted in a time-dependent increase in acetylated histone H3 levels in the cortex and striatum of both ipsilateral and contralateral brain hemispheres of middle cerebral artery occlusion (MCAO) rats, as well as in these brain areas of normal, non-surgical rats, supporting the in vitro finding that VPA is a histone deacetylase (HDAC) inhibitor. Similarly, heat shock protein 70 (HSP70) levels were time-dependently up-regulated by VPA in the cortex and striatum of both ipsilateral and contralateral sides of MCAO rats and in these brain areas of normal rats. Altogether, our results demonstrate that VPA is neuroprotective in the cerebral ischemia model and suggest that the protection mechanisms may involve HDAC inhibition and HSP induction.
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Affiliation(s)
- Ming Ren
- Molecular Neurobiology Section, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, MSC 1363, Bethesda, MD 20892-1363, USA
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50
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Abstract
A large body of evidence has accrued that neuropsychiatric disturbances, such as agitation, are extremely common in Alzheimer's disease. These disturbances are associated with considerable morbidity including earlier nursing home admission, more rapid progression, exacerbation of functional and cognitive deficits, and increased caregiver distress. When attention to social or environmental causes, medical conditions, or other triggers of the behavioral disturbance fails to yield improvement, a role for medication may be indicated, whereby the most dominant behavioral target symptoms are matched to the most relevant medication class. Evidence is reviewed for various medication classes in treating agitation in the patient with Alzheimer's disease, and future treatment strategies may be aimed at delaying or preventing such neuropsychiatric disturbances.
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Affiliation(s)
- Louis A Profenno
- Department of Psychiatry, University of Rochester Medical Center, Monroe Community Hospital, Rochester, NY 14620, USA
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