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van den Berg M, Toen D, Verhoye M, Keliris GA. Alterations in theta-gamma coupling and sharp wave-ripple, signs of prodromal hippocampal network impairment in the TgF344-AD rat model. Front Aging Neurosci 2023; 15:1081058. [PMID: 37032829 PMCID: PMC10075364 DOI: 10.3389/fnagi.2023.1081058] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/27/2023] [Indexed: 04/11/2023] Open
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative disorder caused by the accumulation of toxic proteins, amyloid-beta (Aβ) and tau, which eventually leads to dementia. Disease-modifying therapies are still lacking, due to incomplete insights into the neuropathological mechanisms of AD. Synaptic dysfunction is known to occur before cognitive symptoms become apparent and recent studies have demonstrated that imbalanced synaptic signaling drives the progression of AD, suggesting that early synaptic dysfunction could be an interesting therapeutic target. Synaptic dysfunction results in altered oscillatory activity, which can be detected with electroencephalography and electrophysiological recordings. However, the majority of these studies have been performed at advanced stages of AD, when extensive damage and cognitive symptoms are already present. The current study aimed to investigate if the hippocampal oscillatory activity is altered at pre-plaque stages of AD. The rats received stereotactic surgery to implant a laminar electrode in the CA1 layer of the right hippocampus. Electrophysiological recordings during two consecutive days in an open field were performed in 4-5-month-old TgF344-AD rats when increased concentrations of soluble Aβ species were observed in the brain, in the absence of Aβ-plaques. We observed a decreased power of high theta oscillations in TgF344-AD rats compared to wild-type littermates. Sharp wave-ripple (SWR) analysis revealed an increased SWR power and a decreased duration of SWR during quiet wake in TgF344-AD rats. The alterations in properties of SWR and the increased power of fast oscillations are suggestive of neuronal hyperexcitability, as has been demonstrated to occur during presymptomatic stages of AD. In addition, decreased strength of theta-gamma coupling, an important neuronal correlate of memory encoding, was observed in the TgF344-AD rats. Theta-gamma phase amplitude coupling has been associated with memory encoding and the execution of cognitive functions. Studies have demonstrated that mild cognitive impairment patients display decreased coupling strength, similar to what is described here. The current study demonstrates altered hippocampal network activity occurring at pre-plaque stages of AD and provides insights into prodromal network dysfunction in AD. The alterations observed could aid in the detection of AD during presymptomatic stages.
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Affiliation(s)
- Monica van den Berg
- Bio-Imaging Lab, University of Antwerp, Wilrijk, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- *Correspondence: Monica van den Berg, ; Georgios A. Keliris,
| | - Daniëlle Toen
- Bio-Imaging Lab, University of Antwerp, Wilrijk, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Wilrijk, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Georgios A. Keliris
- Bio-Imaging Lab, University of Antwerp, Wilrijk, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Institute of Computer Science, Foundation for Research and Technology – Hellas, Heraklion, Crete, Greece
- *Correspondence: Monica van den Berg, ; Georgios A. Keliris,
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Kumar M, Bansal N. A Revisit to Etiopathogenesis and Therapeutic Strategies in Alzheimer's Disease. Curr Drug Targets 2021; 23:486-512. [PMID: 34792002 DOI: 10.2174/1389450122666211118125233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/05/2021] [Accepted: 09/13/2021] [Indexed: 11/22/2022]
Abstract
Dementia is a cluster of brain abnormalities that trigger progressive memory deficits and other cognitive abilities such as skills, language, or executive function. Alzheimer's disease (AD) is the foremost type of age-associated dementia that involves progressive neurodegeneration accompanied by profound cognitive deficits in advanced stages that severely hamper social or occupational abilities with or without the involvement of any other psychiatric condition. The last two decades witnessed a sharp increase (~123%) in mortality due to AD type dementia, typically owing to a very low disclosure rate (~45%) and hence, the prophylactic, as well as the therapeutic cure of AD, has been a huge challenge. Although understanding of AD pathogenesis has witnessed a remarkable growth (e.g., tauopathy, oxidative stress, lipid transport, glucose uptake, apoptosis, synaptic dysfunction, inflammation, and immune system), still a dearth of an effective therapeutic agent in the management of AD prompts the quest for newer pharmacological targets in the purview of its growing epidemiological status. Most of the current therapeutic strategies focus on modulation of a single target, e.g., inhibition of acetylcholinesterase, glutamate excitotoxicity (memantine), or nootropics (piracetam), even though AD is a multifaceted neurological disorder. There is an impedance urgency to find not only symptomatic but effective disease-modifying therapies. The present review focuses on the risk / protective factors and pathogenic mechanisms involved in AD. In addition to the existing symptomatic therapeutic approach, a diverse array of possible targets linked to pathogenic cascades have been re-investigated to envisage the pharmacotherapeutic strategies in AD.
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Affiliation(s)
- Manish Kumar
- Chitkara College of Pharmacy, Chitkara University, Punjab. India
| | - Nitin Bansal
- Department of Pharmaceutical Sciences, Chaudhary Bansi Lal University (CBLU), Bhiwani, Haryana 127021. India
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Calabrò M, Rinaldi C, Santoro G, Crisafulli C. The biological pathways of Alzheimer disease: a review. AIMS Neurosci 2020; 8:86-132. [PMID: 33490374 PMCID: PMC7815481 DOI: 10.3934/neuroscience.2021005] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer disease is a progressive neurodegenerative disorder, mainly affecting older people, which severely impairs patients' quality of life. In the recent years, the number of affected individuals has seen a rapid increase. It is estimated that up to 107 million subjects will be affected by 2050 worldwide. Research in this area has revealed a lot about the biological and environmental underpinnings of Alzheimer, especially its correlation with β-Amyloid and Tau related mechanics; however, the precise molecular events and biological pathways behind the disease are yet to be discovered. In this review, we focus our attention on the biological mechanics that may lie behind Alzheimer development. In particular, we briefly describe the genetic elements and discuss about specific biological processes potentially associated with the disease.
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Affiliation(s)
| | | | | | - Concetta Crisafulli
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Italy
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Shin J, Kong C, Lee J, Choi BY, Sim J, Koh CS, Park M, Na YC, Suh SW, Chang WS, Chang JW. Focused ultrasound-induced blood-brain barrier opening improves adult hippocampal neurogenesis and cognitive function in a cholinergic degeneration dementia rat model. ALZHEIMERS RESEARCH & THERAPY 2019; 11:110. [PMID: 31881998 PMCID: PMC6933667 DOI: 10.1186/s13195-019-0569-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/12/2019] [Indexed: 12/14/2022]
Abstract
Background The persistence of adult hippocampal neurogenesis (AHN) is sharply decreased in Alzheimer’s disease (AD). The neuropathologies of AD include the presence of amyloid-β deposition in plaques, tau hyperphosphorylation in neurofibrillary tangles, and cholinergic system degeneration. The focused ultrasound (FUS)-mediated blood-brain barrier opening modulates tau hyperphosphorylation, the accumulation of amyloid-β proteins, and increases in AHN. However, it remains unclear whether FUS can modulate AHN in cholinergic-deficient conditions. In this study, we investigated the effect of FUS on AHN in a cholinergic degeneration rat model of dementia. Methods Adult male Sprague-Dawley rats (n = 48; 200–250 g) were divided into control (phosphate-buffered saline injection), 192 IgG-saporin (SAP), and SAP+FUS groups; in the two latter groups, SAP was injected bilaterally into the lateral ventricle. We applied FUS to the bilateral hippocampus with microbubbles. Immunohistochemistry, enzyme-linked immunosorbent assay, immunoblotting, 5-bromo-2′-deoxyuridine labeling, an acetylcholinesterase assay, and the Morris water maze test were performed to assess choline acetyltransferase, acetylcholinesterase activity, brain-derived neurotrophic factor expression, neural proliferation, and spatial memory, respectively. Statistical significance of differences in between groups was calculated using one-way and two-way analyses of variance followed by Tukey’s multiple comparison test to determine the individual and interactive effects of FUS on immunochemistry and behavioral analysis. P < 0.05 was considered significant. Results Cholinergic degeneration in rats significantly decreased the number of choline acetyltransferase neurons (P < 0.05) in the basal forebrain, as well as AHN and spatial memory function. Rats that underwent FUS-mediated brain-blood barrier opening exhibited significant increases in brain-derived neurotrophic factor (BDNF; P < 0.05), early growth response protein 1 (EGR1) (P < 0.01), AHN (P < 0.01), and acetylcholinesterase activity in the frontal cortex (P < 0.05) and hippocampus (P < 0.01) and crossing over (P < 0.01) the platform in the Morris water maze relative to the SAP group after sonication. Conclusions FUS treatment increased AHN and improved spatial memory. This improvement was mediated by increased hippocampal BDNF and EGR1. FUS treatment may also restore AHN and protect against neurodegeneration, providing a potentially powerful therapeutic strategy for AD.
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Affiliation(s)
- Jaewoo Shin
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.,Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Chanho Kong
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Jihyeon Lee
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.,Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Bo Young Choi
- Department of Physiology, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea
| | - Jiyeon Sim
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.,Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Chin Su Koh
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Minkyung Park
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.,Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Young Cheol Na
- Department of Neurosurgery, Catholic Kwandong University College of Medicine, International St Mary's Hospital, Incheon Metropolitan City, 22771, Republic of Korea
| | - Sang Won Suh
- Department of Physiology, Hallym University College of Medicine, Chuncheon, 24252, Republic of Korea
| | - Won Seok Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
| | - Jin Woo Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea. .,Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
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Neural pathways in medial septal cholinergic modulation of chronic pain: distinct contribution of the anterior cingulate cortex and ventral hippocampus. Pain 2018; 159:1550-1561. [DOI: 10.1097/j.pain.0000000000001240] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Llorente-Ovejero A, Manuel I, Giralt MT, Rodríguez-Puertas R. Increase in cortical endocannabinoid signaling in a rat model of basal forebrain cholinergic dysfunction. Neuroscience 2017; 362:206-218. [PMID: 28827178 DOI: 10.1016/j.neuroscience.2017.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/20/2017] [Accepted: 08/03/2017] [Indexed: 12/24/2022]
Abstract
The basal forebrain cholinergic pathways progressively degenerate during the progression of Alzheimer's disease, leading to an irreversible impairment of memory and thinking skills. The stereotaxic lesion with 192IgG-saporin in the rat brain has been used to eliminate basal forebrain cholinergic neurons and is aimed at emulating the cognitive damage described in this disease in order to explore its effects on behavior and on neurotransmission. Learning and memory processes that are controlled by cholinergic neurotransmission are also modulated by the endocannabinoid (eCB) system. The objective of the present study is to evaluate the eCB signaling in relation to the memory impairment induced in adult rats following a specific cholinergic lesion of the basal forebrain. Therefore, CB1 receptor-mediated signaling was analyzed using receptor and functional autoradiography, and cellular distribution by immunofluorescence. The passive avoidance test and histochemical data revealed a relationship between impaired behavioral responses and a loss of approximately 75% of cholinergic neurons in the nucleus basalis magnocellularis (NBM), accompanied by cortical cholinergic denervation. The decrease in CB1 receptor density observed in the hippocampus, together with hyperactivity of eCB signaling in the NBM and cortex, suggest an interaction between the eCB and cholinergic systems. Moreover, following basal forebrain cholinergic denervation, the presynaptic GABAergic immunoreactivity was reduced in cortical areas. In conclusion, CB1 receptors present in presynaptic GABAergic terminals in the hippocampus are down regulated, but not those in cortical glutamatergic synapses.
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Affiliation(s)
- Alberto Llorente-Ovejero
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Maria Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain.
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Abstract
Alzheimer's disease (AD) is a degenerative brain disease and the most common cause of dementia. AD is characterized by the extracellular amyloid beta (Aβ) plaques and intraneuronal deposits of neurofibrillary tangles (NFTs). Recently, as aging has become a familiar phenomenon around the world, patients with AD are increasing in number. Thus, many researchers are working toward finding effective therapeutics for AD focused on Aβ hypothesis, although there has been no success yet. In this review paper, we suggest that AD is a metabolic disease and that we should focus on metabolites that are affected by metabolic alterations to find effective therapeutics for AD. Aging is associated with not only AD but also obesity and type 2 diabetes (T2DM). AD, obesity, and T2DM share demographic profiles, risk factors, and clinical and biochemical features in common. Considering AD as a kind of metabolic disease, we suggest insulin, adiponectin, and antioxidants as mechanistic links among these diseases and targets for AD therapeutics. Patients with AD show reduced insulin signal transductions in the brain, and intranasal injection of insulin has been found to have an effect on AD treatment. In addition, adiponectin is decreased in the patients with obesity and T2DM. This reduction induces metabolic dysfunction both in the body and the brain, leading to AD pathogenesis. Oxidative stress is known to be induced by Aβ and NFTs, and we suggest that oxidative stress caused by metabolic alterations in the body induce brain metabolic alterations, resulting in AD.
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Affiliation(s)
- Somang Kang
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
- BK21 Plus Project for Medical Sciences and Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Yong Ho Lee
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Jong Eun Lee
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
- BK21 Plus Project for Medical Sciences and Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea. jelee@yuhs
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