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Arshavsky YI. Autoimmune hypothesis of Alzheimer's disease: unanswered question. J Neurophysiol 2024; 132:929-942. [PMID: 39163023 DOI: 10.1152/jn.00259.2024] [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: 06/18/2024] [Revised: 07/24/2024] [Accepted: 07/25/2024] [Indexed: 08/21/2024] Open
Abstract
Alzheimer's disease (AD) was described more than a century ago. However, there are still no effective approaches to its treatment, which may suggest that the search for the cure is not being conducted in the most productive direction. AD begins as selective impairments of declarative memory with no deficits in other cognitive functions. Therefore, understanding of the AD pathogenesis has to include the understanding of this selectivity. Currently, the main efforts aimed at prevention and treatment of AD are based on the dominating hypothesis for the AD pathogenesis: the amyloid hypothesis. But this hypothesis does not explain selective memory impairments since β-amyloid accumulates extracellularly and should be toxic to all types of cerebral neurons, not only to "memory engram neurons." To explain selective memory impairment, I propose the autoimmune hypothesis of AD, based on the analysis of risk factors for AD and molecular mechanisms of memory formation. Memory formation is associated with epigenetic modifications of chromatin in memory engram neurons and, therefore, might be accompanied by the expression of memory-specific proteins recognized by the adaptive immune system as "non-self" antigens. Normally, the brain is protected by the blood-brain barrier (BBB). All risk factors for AD provoke BBB disruptions, possibly leading to an autoimmune reaction against memory engram neurons. This reaction would make them selectively sensitive to tauopathy. If this hypothesis is confirmed, the strategies for AD prevention and treatment would be radically changed.
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Affiliation(s)
- Yuri I Arshavsky
- BioCircuits Institute, University of California, San Diego, La Jolla, California, United States
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Bermejo-Pareja F, del Ser T. Controversial Past, Splendid Present, Unpredictable Future: A Brief Review of Alzheimer Disease History. J Clin Med 2024; 13:536. [PMID: 38256670 PMCID: PMC10816332 DOI: 10.3390/jcm13020536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/29/2023] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
Background: The concept of Alzheimer disease (AD)-since its histological discovery by Alzheimer to the present day-has undergone substantial modifications. Methods: We conducted a classical narrative review of this field with a bibliography selection (giving preference to Medline best match). Results: The following subjects are reviewed and discussed: Alzheimer's discovery, Kraepelin's creation of a new disease that was a rare condition until the 1970's, the growing interest and investment in AD as a major killer in a society with a large elderly population in the second half of the 20th century, the consolidation of the AD clinicopathological model, and the modern AD nosology based on the dominant amyloid hypothesis among many others. In the 21st century, the development of AD biomarkers has supported a novel biological definition of AD, although the proposed therapies have failed to cure this disease. The incidence of dementia/AD has shown a decrease in affluent countries (possibly due to control of risk factors), and mixed dementia has been established as the most frequent etiology in the oldest old. Conclusions: The current concept of AD lacks unanimity. Many hypotheses attempt to explain its complex physiopathology entwined with aging, and the dominant amyloid cascade has yielded poor therapeutic results. The reduction in the incidence of dementia/AD appears promising but it should be confirmed in the future. A reevaluation of the AD concept is also necessary.
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Affiliation(s)
- Félix Bermejo-Pareja
- CIBERNED, Institute of Health Carlos III, 28029 Madrid, Spain
- Institute of Research i+12, University Hospital “12 de Octubre”, 28041 Madrid, Spain
| | - Teodoro del Ser
- Alzheimer’s Centre Reina Sofia—CIEN Foundation, Institute of Health Carlos III, 28031 Madrid, Spain;
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Miranda M, Morici JF, Zanoni MB, Bekinschtein P. Brain-Derived Neurotrophic Factor: A Key Molecule for Memory in the Healthy and the Pathological Brain. Front Cell Neurosci 2019; 13:363. [PMID: 31440144 PMCID: PMC6692714 DOI: 10.3389/fncel.2019.00363] [Citation(s) in RCA: 764] [Impact Index Per Article: 127.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/25/2019] [Indexed: 12/13/2022] Open
Abstract
Brain Derived Neurotrophic Factor (BDNF) is a key molecule involved in plastic changes related to learning and memory. The expression of BDNF is highly regulated, and can lead to great variability in BDNF levels in healthy subjects. Changes in BDNF expression are associated with both normal and pathological aging and also psychiatric disease, in particular in structures important for memory processes such as the hippocampus and parahippocampal areas. Some interventions like exercise or antidepressant administration enhance the expression of BDNF in normal and pathological conditions. In this review, we will describe studies from rodents and humans to bring together research on how BDNF expression is regulated, how this expression changes in the pathological brain and also exciting work on how interventions known to enhance this neurotrophin could have clinical relevance. We propose that, although BDNF may not be a valid biomarker for neurodegenerative/neuropsychiatric diseases because of its disregulation common to many pathological conditions, it could be thought of as a marker that specifically relates to the occurrence and/or progression of the mnemonic symptoms that are common to many pathological conditions.
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Affiliation(s)
- Magdalena Miranda
- Laboratory of Memory Research and Molecular Cognition, Institute for Cognitive and Translational Neuroscience, Instituto de Neurología Cognitiva, CONICET, Universidad Favaloro, Buenos Aires, Argentina
| | - Juan Facundo Morici
- Laboratory of Memory Research and Molecular Cognition, Institute for Cognitive and Translational Neuroscience, Instituto de Neurología Cognitiva, CONICET, Universidad Favaloro, Buenos Aires, Argentina
| | - María Belén Zanoni
- Laboratory of Memory Research and Molecular Cognition, Institute for Cognitive and Translational Neuroscience, Instituto de Neurología Cognitiva, CONICET, Universidad Favaloro, Buenos Aires, Argentina
| | - Pedro Bekinschtein
- Laboratory of Memory Research and Molecular Cognition, Institute for Cognitive and Translational Neuroscience, Instituto de Neurología Cognitiva, CONICET, Universidad Favaloro, Buenos Aires, Argentina
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Wu L, Feng XT, Hu YQ, Tang N, Zhao QS, Li TW, Li HY, Wang QB, Bi XY, Cai XK. Global Gene Expression Profile of the Hippocampus in a Rat Model of Vascular Dementia. TOHOKU J EXP MED 2016; 237:57-67. [PMID: 26353909 DOI: 10.1620/tjem.237.57] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Vascular dementia (VD) has been one of the most serious public health problems worldwide. It is well known that cerebral hypoperfusion is the key pathophysiological basis of VD, but it remains unclear how global genes in hippocampus respond to cerebral ischemia-reperfusion. In this study, we aimed to reveal the global gene expression profile in the hippocampus of VD using a rat model. VD was induced by repeated occlusion of common carotid arteries followed by reperfusion. The rats with VD were characterized by deficit of memory and cognitive function and by the histopathological changes in the hippocampus, such as a reduction in the number and the size of neurons accompanied by an increase in intercellular space. Microarray analysis of global genes displayed up-regulation of 7 probesets with genes with fold change more than 1.5 (P < 0.05) and down-regulation of 13 probesets with genes with fold change less than 0.667 (P < 0.05) in the hippocampus. Gene Ontology (GO) and pathway analysis showed that the up-regulated genes are mainly involved in oxygen binding and transport, autoimmune response and inflammation, and that the down-regulated genes are related to glucose metabolism, autoimmune response and inflammation, and other biological process, related to memory and cognitive function. Thus, the abnormally expressed genes are closely related to oxygen transport, glucose metabolism, and autoimmune response. The current findings display global gene expression profile of the hippocampus in a rat model of VD, providing new insights into the molecular pathogenesis of VD.
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Affiliation(s)
- Lin Wu
- Guangxi Scientific Experimental Center of Traditional Chinese Medicine, Guangxi University of Chinese Medicine
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Karczewski P, Hempel P, Kunze R, Bimmler M. Agonistic Autoantibodies to the α1-Adrenergic Receptor and the β2-Adrenergic Receptor in Alzheimer’s and Vascular Dementia. Scand J Immunol 2012; 75:524-30. [DOI: 10.1111/j.1365-3083.2012.02684.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Sardi F, Fassina L, Venturini L, Inguscio M, Guerriero F, Rolfo E, Ricevuti G. Alzheimer's disease, autoimmunity and inflammation. The good, the bad and the ugly. Autoimmun Rev 2011; 11:149-53. [DOI: 10.1016/j.autrev.2011.09.005] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/19/2011] [Indexed: 11/26/2022]
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Kapadia M, Sakic B. Autoimmune and inflammatory mechanisms of CNS damage. Prog Neurobiol 2011; 95:301-33. [PMID: 21889967 DOI: 10.1016/j.pneurobio.2011.08.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 08/18/2011] [Accepted: 08/19/2011] [Indexed: 12/13/2022]
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Hampl R, Bicíková M. Neuroimmunomodulatory steroids in Alzheimer dementia. J Steroid Biochem Mol Biol 2010; 119:97-104. [PMID: 20153425 DOI: 10.1016/j.jsbmb.2010.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 02/03/2010] [Accepted: 02/04/2010] [Indexed: 01/09/2023]
Abstract
Though pathobiochemical and neurochemical changes and accompanied morphological alterations in Alzheimer dementia are well known, the triggering mechanisms, if any, remain obscure. Important factors influencing the development and progression of Alzheimer disease include hormonal steroids and their metabolites, some of which may serve as therapeutic agents. This review focusses on major biochemical alterations in the brain of Alzheimer patients with respect to the involvement of steroids. It includes their role in impairment of fuel supply and in brain glycoregulation, with especial emphasis on glucocorticoids and their counter-regulatory steroids as dehydroepiandrosterone and its metabolites. Further, the role of steroids in beta-amyloid pathology is reviewed including alterations in tau-protein(s) phosphorylation. The (auto)immune theory of Alzheimer dementia is briefly outlined, pointing to the possible involvement of steroids in brain ageing, immunosenescence and neuronal apoptosis. Some effects of steroids are briefly mentioned on the formation and removal of reactive oxygen species and their effect on calcium flux and cytotoxicity. The recent biochemical research of Alzheimer disease focusses on molecular signalling at which steroids also take part. New findings may be anticipated when the mosaic describing the molecular mechanisms behind these events becomes more complete.
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Han C, Kim NH, Kwon DY, Seo WK, Park MH. Lack of association between antisperm antibodies and language dysfunction in Alzheimer's disease. Arch Gerontol Geriatr 2009; 50:338-40. [PMID: 19573931 DOI: 10.1016/j.archger.2009.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 05/24/2009] [Accepted: 05/26/2009] [Indexed: 10/20/2022]
Abstract
Alzheimer's disease (AD) is the single most common cause of primary dementia. Language-based frontotemporal dementia, another type of primary dementia, is known as primary progressive aphasia (PPA). Although the cardinal feature of AD is a progressive loss of memory, many patients with AD also present with language impairment. Moreover AD and PPA have partially shared pathophysiology. Recently, it was suggested that a history of vasectomy might be a risk factor for PPA, by immune responses to sperm or antisperm antibody (ASA), which has long been known to have antigenic property. As ASAs could develop naturally in both men and women, we studied the relation between the presence of ASAs and cognitive function in AD. A total of 86 elderly were selected (46 patient with AD, 20 with mild cognitive impairment, and 20 without cognitive dysfunction) and were assessed for the presence of ASAs with neuropsychological evaluation. However, there were no significant differences in the distribution of ASAs according to cognitive status or language function status. Thus, the current study does not support the association between the immune responses and language dysfunction in AD.
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Affiliation(s)
- Changsu Han
- Geriatric Health Clinic and Research Institute, Korea University Ansan Hospital, and Department of Psychiatry, Korea University Medical College, 516 Gojan-1-dong, Danwon-gu, Ansan, Gyeonggi-do 425-707, Republic of Korea
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Pluta R, Amek MU. Brain ischemia and ischemic blood-brain barrier as etiological factors in sporadic Alzheimer's disease. Neuropsychiatr Dis Treat 2008; 4:855-64. [PMID: 19183778 PMCID: PMC2626921 DOI: 10.2147/ndt.s3739] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The development of neuronal death and amyloid plaques is a characteristic feature of ischemic- and Alzheimer-type dementia. An important aspect of neuronal loss and amyloid plaques are their topography and neuropathogenesis. This review was performed to present the hypothesis that different fragments of blood-borne amyloid precursor protein are able to enter the ischemic blood-brain barrier. Chronic disruption of the blood-brain barrier after ischemic injury was shown. As an effect of chronic ischemic blood-brain barrier injury, a visible connection of amyloid plaques with neurovasculature was observed. This neuropathology appears to have similar distribution and mechanisms to Alzheimer's disease. The usefulness of rival ischemic theory in elucidating the neuropathogenesis of amyloid plaques formation and neuronal death in Alzheimer's disorder is discussed.
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Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Department of Neurodegenerative Disorders, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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Boscolo S, Tongiorgi E. Quantification of antineural antibodies in autoimmune neurological disorders. Expert Rev Clin Immunol 2007; 3:949-73. [PMID: 20477143 DOI: 10.1586/1744666x.3.6.949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
More than 50 different neurological pathologies have a confirmed or suspected autoimmune etiology affecting an estimated number of 75 million people worldwide. Autoantibodies are a useful diagnostic marker for most autoimmune diseases even though their pathological role is not evident, and several tests for their detection are commercially available. However, for autoimmune diseases involving the nervous system, lack of clear information on the identity of antineural antibody targets and the presence of many rare diseases have hampered the development of specific diagnostic assays. This review focuses on the actual knowledge on confirmed and suspected autoimmune diseases that target the CNS and the diagnostic relevance of corresponding antineural autoantibodies.
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Affiliation(s)
- Sabrina Boscolo
- BRAIN Centre for Neuroscience, Department of Biology, University of Trieste, Via Giorgieri, 10. 34127 Trieste, Italy.
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Abstract
Although the effect of estrogen replacement therapy on the incidence of the neurodegenerative disease such as Alzheimer's disease is controversial, experimental studies indicate that estrogen replacement to young adult animals is neuroprotective and that perimenopausal estrogen replacement is associated with a decreased incidence of Alzheimer's disease. Estrogen affects a wide variety of cellular processes that can protect neuronal health. This article considers the disruption of the blood-brain barrier in Alzheimer's disease and forwards the hypothesis that estrogen may preserve neural health by maintaining the integrity of the blood-brain barrier.
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Affiliation(s)
- Farida Sohrabji
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, College Station, TX 77843, USA.
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Jellinger KA. Alzheimer 100 – highlights in the history of Alzheimer research. J Neural Transm (Vienna) 2006; 113:1603-23. [PMID: 17039299 DOI: 10.1007/s00702-006-0578-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 09/11/2006] [Indexed: 11/24/2022]
Abstract
Alzheimer disease, a progressive neurodegenerative disorder of hitherto unknown etiology leading progressively to severe incapacity and death, has become the pandemic of the 21(st) century. On World Alzheimer Day, September 21, 2006, the 100(th) anniversary of the first description of the clinical and histological findings in this disorder by A. Alzheimer, was celebrated. This retrospective review of the most important events and advances in Alzheimer research presents its early history in which only clinical and histologic signs of this peculiar disease were described. Electron microscopy, quantitative morphology and modern biochemistry emerging in the second half of the 20(th) century opened a new era in dementia research with description of the ultrastructure and biochemistry of senile plaques and neurofibrillary tangles, the major disease markers of AD. Advances in the development of clinical, neuropathological, and neuroimaging criteria, modern instruments and algorithms in the diagnosis of the disorder followed, enabling long-term studies and more exact diagnosis of AD and related disorders. Landmark studies were the development of operational criteria for the post mortem diagnosis of AD based on semiquantitative assessment and developmental patterns of its major markers. Basic research gave insight into the molecular genetics and pathophysiology of AD, and, based on the biochemical findings, new pharmacological treatment options were opened. Recently, biological and other surrogate, in particular functional neuroimaging, markers allow an early detection of presymptomatic stages of AD, their risk factors and progression which, in the future, might be prevented or at least slowed by new therapeutic approaches. Since the etiology of AD is hitherto unknown, causative therapies are still not available. The paper discusses future research needs and challenges for developing new diagnostic strategies for early and accurate detection of neurodegenerative processes leading to dementia, better epidemiologic and gender data as well as more insights into the pathogenic cascade of AD and other dementing disorders which will depend on international networks and close cooperation between clinicians, neuroscientists, caregivers, public health institutions, and individual sponsors.
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Affiliation(s)
- K A Jellinger
- Institute of Clinical Neurobiology, Vienna, Austria.
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Arshavsky YI. “The seven sins” of the Hebbian synapse: Can the hypothesis of synaptic plasticity explain long-term memory consolidation? Prog Neurobiol 2006; 80:99-113. [PMID: 17074430 DOI: 10.1016/j.pneurobio.2006.09.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 09/25/2006] [Accepted: 09/26/2006] [Indexed: 11/16/2022]
Abstract
Memorizing new facts and events means that entering information produces specific physical changes within the brain. According to the commonly accepted view, traces of memory are stored through the structural modifications of synaptic connections, which result in changes of synaptic efficiency and, therefore, in formations of new patterns of neural activity (the hypothesis of synaptic plasticity). Most of the current knowledge on learning and initial stages of memory consolidation ("synaptic consolidation") is based on this hypothesis. However, the hypothesis of synaptic plasticity faces a number of conceptual and experimental difficulties when it deals with potentially permanent consolidation of declarative memory ("system consolidation"). These difficulties are rooted in the major intrinsic self-contradiction of the hypothesis: stable declarative memory is unlikely to be based on such a non-stable foundation as synaptic plasticity. Memory that can last throughout an entire lifespan should be "etched in stone." The only "stone-like" molecules within living cells are DNA molecules. Therefore, I advocate an alternative, genomic hypothesis of memory, which suggests that acquired information is persistently stored within individual neurons through modifications of DNA, and that these modifications serve as the carriers of elementary memory traces.
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Affiliation(s)
- Yuri I Arshavsky
- Institute for Nonlinear Science, University of California San Diego, La Jolla, CA 92093-0402, USA.
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