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Abbate C. The Adult Neurogenesis Theory of Alzheimer's Disease. J Alzheimers Dis 2023:JAD221279. [PMID: 37182879 DOI: 10.3233/jad-221279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Alzheimer's disease starts in neural stem cells (NSCs) in the niches of adult neurogenesis. All primary factors responsible for pathological tau hyperphosphorylation are inherent to adult neurogenesis and migration. However, when amyloid pathology is present, it strongly amplifies tau pathogenesis. Indeed, the progressive accumulation of extracellular amyloid-β deposits in the brain triggers a state of chronic inflammation by microglia. Microglial activation has a significant pro-neurogenic effect that fosters the process of adult neurogenesis and supports neuronal migration. Unfortunately, this "reactive" pro-neurogenic activity ultimately perturbs homeostatic equilibrium in the niches of adult neurogenesis by amplifying tau pathogenesis in AD. This scenario involves NSCs in the subgranular zone of the hippocampal dentate gyrus in late-onset AD (LOAD) and NSCs in the ventricular-subventricular zone along the lateral ventricles in early-onset AD (EOAD), including familial AD (FAD). Neuroblasts carrying the initial seed of tau pathology travel throughout the brain via neuronal migration driven by complex signals and convey the disease from the niches of adult neurogenesis to near (LOAD) or distant (EOAD) brain regions. In these locations, or in close proximity, a focus of degeneration begins to develop. Then, tau pathology spreads from the initial foci to large neuronal networks along neural connections through neuron-to-neuron transmission.
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Affiliation(s)
- Carlo Abbate
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
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Anan’ina T, Kisel A, Kudabaeva M, Chernysheva G, Smolyakova V, Usov K, Krutenkova E, Plotnikov M, Khodanovich M. Neurodegeneration, Myelin Loss and Glial Response in the Three-Vessel Global Ischemia Model in Rat. Int J Mol Sci 2020; 21:ijms21176246. [PMID: 32872364 PMCID: PMC7504277 DOI: 10.3390/ijms21176246] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
(1) Background: Although myelin disruption is an integral part of ischemic brain injury, it is rarely the subject of research, particularly in animal models. This study assessed for the first time, myelin and oligodendrocyte loss in a three-vessel model of global cerebral ischemia (GCI), which causes hippocampal damage. In addition, we investigated the relationships between demyelination and changes in microglia and astrocytes, as well as oligodendrogenesis in the hippocampus; (2) Methods: Adult male Wistar rats (n = 15) underwent complete interruption of cerebral blood flow for 7 min by ligation of the major arteries supplying the brain or sham-operation. At 10 and 30 days after the surgery, brain slices were stained for neurodegeneration with Fluoro-Jade C and immunohistochemically to assess myelin content (MBP+ percentage of total area), oligodendrocyte (CNP+ cells) and neuronal (NeuN+ cells) loss, neuroinflammation (Iba1+ cells), astrogliosis (GFAP+ cells) and oligodendrogenesis (NG2+ cells); (3) Results: 10 days after GCI significant myelin and oligodendrocyte loss was found only in the stratum oriens and stratum pyramidale. By the 30th day, demyelination in these hippocampal layers intensified and affected the substratum radiatum. In addition to myelin damage, activation and an increase in the number of microglia and astrocytes in the corresponding layers, a loss of the CA1 pyramidal neurons, and neurodegeneration in the neocortex and thalamus was observed. At a 10-day time point, we observed rod-shaped microglia in the substratum radiatum. Parallel with ongoing myelin loss on the 30th day after ischemia, we found significant oligodendrogenesis in demyelinated hippocampal layers; (4) Conclusions: Our study showed that GCI-simulating cardiac arrest in humans—causes not only the loss of pyramidal neurons in the CA1 field, but also the myelin loss of adjacent layers of the hippocampus.
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Affiliation(s)
- Tatiana Anan’ina
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Lenina Ave., 634050 Tomsk, Russia; (T.A.); (A.K.); (M.K.); (K.U.); (E.K.)
| | - Alena Kisel
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Lenina Ave., 634050 Tomsk, Russia; (T.A.); (A.K.); (M.K.); (K.U.); (E.K.)
| | - Marina Kudabaeva
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Lenina Ave., 634050 Tomsk, Russia; (T.A.); (A.K.); (M.K.); (K.U.); (E.K.)
| | - Galina Chernysheva
- Laboratory of Pharmacology of Blood Circulation, E. D. Goldberg Research Institute of Pharmacology and Regenerative Medicine, Tomsk National Research Medical Center, Russian Academy of Sciences, Lenina Ave., 634028 Tomsk, Russia; (G.C.); (V.S.); (M.P.)
| | - Vera Smolyakova
- Laboratory of Pharmacology of Blood Circulation, E. D. Goldberg Research Institute of Pharmacology and Regenerative Medicine, Tomsk National Research Medical Center, Russian Academy of Sciences, Lenina Ave., 634028 Tomsk, Russia; (G.C.); (V.S.); (M.P.)
| | - Konstantin Usov
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Lenina Ave., 634050 Tomsk, Russia; (T.A.); (A.K.); (M.K.); (K.U.); (E.K.)
| | - Elena Krutenkova
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Lenina Ave., 634050 Tomsk, Russia; (T.A.); (A.K.); (M.K.); (K.U.); (E.K.)
| | - Mark Plotnikov
- Laboratory of Pharmacology of Blood Circulation, E. D. Goldberg Research Institute of Pharmacology and Regenerative Medicine, Tomsk National Research Medical Center, Russian Academy of Sciences, Lenina Ave., 634028 Tomsk, Russia; (G.C.); (V.S.); (M.P.)
| | - Marina Khodanovich
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Lenina Ave., 634050 Tomsk, Russia; (T.A.); (A.K.); (M.K.); (K.U.); (E.K.)
- Correspondence:
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Khodanovich MY, Kisel’ AA, Chernysheva GA, Smol’yakova VI, Kudabaeva MS, Krutenkova EP, Tyumentseva YА, Plotnikov MB. p-Tyrosol Enhances the Production of New Neurons in the Hippocampal CA1 Field after Transient Global Cerebral Ischemia in Rats. Bull Exp Biol Med 2019; 168:224-228. [DOI: 10.1007/s10517-019-04679-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Indexed: 10/25/2022]
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Nemirovich-Danchenko NM, Khodanovich MY. New Neurons in the Post-ischemic and Injured Brain: Migrating or Resident? Front Neurosci 2019; 13:588. [PMID: 31275097 PMCID: PMC6591486 DOI: 10.3389/fnins.2019.00588] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 05/23/2019] [Indexed: 12/11/2022] Open
Abstract
The endogenous potential of adult neurogenesis is of particular interest for the development of new strategies for recovery after stroke and traumatic brain injury. These pathological conditions affect endogenous neurogenesis in two aspects. On the one hand, injury usually initiates the migration of neuronal precursors (NPCs) to the lesion area from the already existing, in physiological conditions, neurogenic niche - the ventricular-subventricular zone (V-SVZ) near the lateral ventricles. On the other hand, recent studies have convincingly demonstrated the local generation of new neurons near lesion areas in different brain locations. The striatum, cortex, and hippocampal CA1 region are considered to be locations of such new neurogenic zones in the damaged brain. This review focuses on the relative contribution of two types of NPCs of different origin, resident population in new neurogenic zones and cells migrating from the lateral ventricles, to post-stroke or post-traumatic enhancement of neurogenesis. The migratory pathways of NPCs have also been considered. In addition, the review highlights the advantages and limitations of different methodological approaches to the definition of NPC location and tracking of new neurons. In general, we suggest that despite the considerable number of studies, we still lack a comprehensive understanding of neurogenesis in the damaged brain. We believe that the advancement of methods for in vivo visualization and longitudinal observation of neurogenesis in the brain could fundamentally change the current situation in this field.
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Affiliation(s)
| | - Marina Yu. Khodanovich
- Laboratory of Neurobiology, Research Institute of Biology and Biophysics, Tomsk State University, Tomsk, Russia
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Sun Y, Sun X, Qu H, Zhao S, Xiao T, Zhao C. Neuroplasticity and behavioral effects of fluoxetine after experimental stroke. Restor Neurol Neurosci 2018; 35:457-468. [PMID: 28854520 DOI: 10.3233/rnn-170725] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The brain can undergo self-repair and has the ability to compensate for functions lost after a stroke. The plasticity of the ischemic brain is influenced by several factors including aging and pharmacotherapy. Fluoxetine is an antidepressant which enhances serotonergic neurotransmission through selective inhibition of neuronal reuptake of serotonin. In clinical practice, fluoxetine alleviates the symptoms of post-stroke depression (PSD), helps motor recovery in stroke patients. In animal experiments, chronic administration of fluoxetine induces increased excitability of mature granule cells (GCs), enhancing axonal and dendritic reorganization, as well as promoting neurogenesis or angiogenesis in the dentate gurus (DG), but the effect of fluoxetine in the subventricular zone (SVZ) remains controversial. Meanwhile, chronic treatment with fluoxetine did not reverse age-dependent suppression of proliferation cells in the DG. Interestingly, although fluoxetine has been found to enhance neurogenesis in the DG in stroke rats, this property is not consistent with the behavioral recovery. More studies into this issue will be required to reveal how to translate enhanced neuronal plasticity into behavioral benefits. This review provides an update of the current knowledge about the neurogenesis and the fate of the newly generated cells after the use of fluoxetine, as well as its ability to promote a behavioral recovery after stroke in clinical and experimental results and attempts to define the therapeutic properties of fluoxetine in regenerative neuroscience.
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Affiliation(s)
- Yefei Sun
- Gastrointestinal Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Xiaoyu Sun
- Department of Neurology, The People's Hospital of Liaoning Province, Shenyang, China
| | - Huiling Qu
- Department of Neurology, The People's Hospital of Liaoning Province, Shenyang, China
| | - Shanshan Zhao
- Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Ting Xiao
- Dermatology, The First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Immunodermatology, Ministry of Health, Ministry of Education, Shenyang, China
| | - Chuansheng Zhao
- Neurology, The First Hospital of China Medical University, Shenyang, China
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Effects of Fluoxetine on Hippocampal Neurogenesis and Neuroprotection in the Model of Global Cerebral Ischemia in Rats. Int J Mol Sci 2018; 19:ijms19010162. [PMID: 29304004 PMCID: PMC5796111 DOI: 10.3390/ijms19010162] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/27/2017] [Accepted: 01/02/2018] [Indexed: 01/17/2023] Open
Abstract
A selective serotonin reuptake inhibitor, fluoxetine, has recently attracted a significant interest as a neuroprotective therapeutic agent. There is substantial evidence of improved neurogenesis under fluoxetine treatment of brain ischemia in animal stroke models. We studied long-term effects of fluoxetine treatment on hippocampal neurogenesis, neuronal loss, inflammation, and functional recovery in a new model of global cerebral ischemia (GCI). Brain ischemia was induced in adult Wistar male rats by transient occlusion of three main vessels originating from the aortic arch and providing brain blood supply. Fluoxetine was injected intraperitoneally in a dose of 20 mg/kg for 10 days after surgery. To evaluate hippocampal neurogenesis at time points 10 and 30 days, 5-Bromo-2′-deoxyuridine was injected at days 8–10 after GCI. According to our results, 10-day fluoxetine injections decreased neuronal loss and inflammation, improved survival and functional recovery of animals, enhanced neurogenesis, and prevented an early pathological increase in neural stem cell recruitment in the subgranular zone (SGZ) of the hippocampus without reducing the number of mature neurons at day 30 after GCI. In summary, this study suggests that fluoxetine may provide a promising therapy in cerebral ischemia due to its neuroprotective, anti-inflammatory, and neurorestorative effect.
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Jayakumar S, Raghunath G, Ilango S, Vijayakumar J, Vijayaraghavan R. Effect of Fluoxetine on the Hippocampus of Wistar Albino Rats in Cold Restraint Stress Model. J Clin Diagn Res 2017; 11:AF01-AF06. [PMID: 28764145 DOI: 10.7860/jcdr/2017/26958.9953] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/06/2017] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Stress has been known to be a potential modulator of learning and memory. Long term stress can lead to depression. Fluoxetine is a selective serotonin reuptake inhibitor group of drug used in the treatment of depression. AIM The present study was conducted to evaluate the potential of Fluoxetine on cold restraint induced stress in the hippocampus of Wistar rats. MATERIALS AND METHODS A total of 18 male wistar albino rats were divided randomly into three groups (n=6). Group 1 was the control group which were kept in normal laboratory conditions. Group 2 was the negative control group which were given cold restraint stress for period of four weeks. Group 3 was the experimental group, where the animals were pretreated with fluoxetine 10 mg/kg for a period of one week followed by cold restraint stress for 30 minutes and cotreated with fluoxetine 10 mg/kg for a period of four weeks. The whole study was done for a period of five weeks followed by behavioural studies and subsequently sacrificed with removal of brain for various histological, Immunohistochemical (IHC), neurochemical and antioxidant analysis. The values were expressed as Mean±SEM. One-way analysis of variance followed by Tukey's multiple comparisons test was used for the comparison of means. A probability of 0.05 and less was taken as statistically significant using Prism Graphpad software version 6.01. RESULTS The results show there was significant improvement in the Morris water maze test after treatment with fluoxetine in Group 2. Similar results were also noted in the levels of neurotransmitters and antioxidant levels in brain and also in the number of cells counted in IHC and histological studies by H&E when Group 3 was compared with Group 2. The treatment reversed the damage in Group 2 which was comparable with the control group. CONCLUSION The results revealed that administration of fluoxetine 10 mg/kg given orally has a potential antistressor effect by improving the neurogenic and neuroprotective effect on the cold restraint stress induced hippocampal damage.
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Affiliation(s)
- Saikarthik Jayakumar
- Research Scholar, Department of Anatomy, Saveetha University, Chennai, Tamil Nadu, India
| | - Gunapriya Raghunath
- Professor and Head, Department of Anatomy, Saveetha Medical College, Chennai, Tamil Nadu, India
| | - Saraswathi Ilango
- Research Scholar, Department of Physiology, Bharath University, Chennai, Tamil Nadu, India
| | - J Vijayakumar
- Professor, Department of Anatomy, Saveetha Medical College, Chennai, Tamil Nadu, India
| | - R Vijayaraghavan
- Director of Research, Department of Anatomy, Saveetha University, Chennai, Tamil Nadu, India
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