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Gelibter S, Saraceno L, Pirro F, Susani EL, Protti A. As time goes by: Treatment challenges in elderly people with multiple sclerosis. J Neuroimmunol 2024; 391:578368. [PMID: 38761652 DOI: 10.1016/j.jneuroim.2024.578368] [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: 12/20/2023] [Revised: 03/11/2024] [Accepted: 05/12/2024] [Indexed: 05/20/2024]
Abstract
A demographic shift in multiple sclerosis (MS) is leading to an increased number of elderly people with MS (pwMS) and a rise in late-onset MS (LOMS) cases. This shift adds complexity to the treatment management of these patients, due to enhanced treatment-associated risks and the possible interplay between immunosenescence and disease-modifying therapies (DMTs). In the present paper, we performed a systematic review of the current evidence concerning the relationship between aging and treatment management in elderly pwMS. Our literature search identified 35 original studies relevant to this topic. The gathered evidence consistently indicates a diminished efficacy of DMTs in older pwMS, particularly in preventing disability accrual. Against this background, high-efficacy therapies (HETs) appear to show less benefit over moderate-low-efficacy DMTs in older patients. These data mainly derive from observational retrospective studies or meta-analyses conducted on randomized clinical trials (RCTs). RCTs, however, exclude pwMS older than 55 years, limiting our ability to acquire robust evidence regarding this patient group. Regarding treatment discontinuation in elderly pwMS with stable disease, the available data, which mainly focuses on older injectable DMTs, suggests that their suspension appears to be relatively safe in terms of disease activity. Nevertheless, the first RCT specifically targeting treatment discontinuation recently failed to demonstrate the non-inferiority of treatment discontinuation over continuation, in terms of MRI activity. On the other hand, the evidence on the impact of discontinuation on disease progression is more conflicting and less robust. Furthermore, there is an important lack of studies concerning sequestering DMTs and virtually no data on the discontinuation of anti-CD20 monoclonal antibodies. De-escalation strategy is gaining attention as a de-risking approach alternative to complete treatment discontinuation. It may be defined as the decision to shift from HETs to less potent DMTs in elderly pwMS who have a stable disease. This strategy could reduce treatment-related risks, while minimizing the risk of disease activity and progression potentially associated with treatment discontinuation. This approach, however, remains unexplored due to a lack of studies. Given these findings, the present scenario underlines the urgent need for more comprehensive and robust studies to develop optimized, data-driven treatment strategies for elderly pwMS and LOMS, addressing the unique challenges of MS treatment and aging.
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Affiliation(s)
- Stefano Gelibter
- Department of Neurosciences, Neurology and Stroke Unit, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy.
| | - Lorenzo Saraceno
- Department of Neurosciences, Neurology and Stroke Unit, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Fiammetta Pirro
- Department of Neurosciences, Neurology and Stroke Unit, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Emanuela Laura Susani
- Department of Neurosciences, Neurology and Stroke Unit, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Alessandra Protti
- Department of Neurosciences, Neurology and Stroke Unit, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
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Da Silva DE, Richards CM, McRae SA, Riar I, Yang S(S, Zurfluh NE, Gibon J, Klegeris A. Extracellular mixed histones are neurotoxic and modulate select neuroimmune responses of glial cells. PLoS One 2024; 19:e0298748. [PMID: 38630734 PMCID: PMC11023449 DOI: 10.1371/journal.pone.0298748] [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: 05/15/2023] [Accepted: 01/29/2024] [Indexed: 04/19/2024] Open
Abstract
Although histone proteins are widely known for their intranuclear functions where they organize DNA, all five histone types can also be released into the extracellular space from damaged cells. Extracellular histones can interact with pattern recognition receptors of peripheral immune cells, including toll-like receptor 4 (TLR4), causing pro-inflammatory activation, which indicates they may act as damage-associated molecular patterns (DAMPs) in peripheral tissues. Very limited information is available about functions of extracellular histones in the central nervous system (CNS). To address this knowledge gap, we applied mixed histones (MH) to cultured cells modeling neurons, microglia, and astrocytes. Microglia are the professional CNS immunocytes, while astrocytes are the main support cells for neurons. Both these cell types are critical for neuroimmune responses and their dysregulated activity contributes to neurodegenerative diseases. We measured effects of extracellular MH on cell viability and select neuroimmune functions of microglia and astrocytes. MH were toxic to cultured primary murine neurons and also reduced viability of NSC-34 murine and SH-SY5Y human neuron-like cells in TLR4-dependent manner. MH did not affect the viability of resting or immune-stimulated BV-2 murine microglia or U118 MG human astrocytic cells. When applied to BV-2 cells, MH enhanced secretion of the potential neurotoxin glutamate, but did not modulate the release of nitric oxide (NO), tumor necrosis factor-α (TNF), C-X-C motif chemokine ligand 10 (CXCL10), or the overall cytotoxicity of lipopolysaccharide (LPS)- and/or interferon (IFN)-γ-stimulated BV-2 microglial cells towards NSC-34 neuron-like cells. We demonstrated, for the first time, that MH downregulated phagocytic activity of LPS-stimulated BV-2 microglia. However, MH also exhibited protective effect by ameliorating the cytotoxicity of LPS-stimulated U118 MG astrocytic cells towards SH-SY5Y neuron-like cells. Our data demonstrate extracellular MH could both damage neurons and alter neuroimmune functions of glial cells. These actions of MH could be targeted for treatment of neurodegenerative diseases.
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Affiliation(s)
- Dylan E. Da Silva
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Christy M. Richards
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Seamus A. McRae
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Ishvin Riar
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Sijie (Shirley) Yang
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Noah E. Zurfluh
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Julien Gibon
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
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Shin HJ, Kim IS, Choi SG, Lee K, Park H, Shin J, Kim D, Beom J, Yi YY, Gupta DP, Song GJ, Chung WS, Lee CJ, Kim DW. Rejuvenating aged microglia by p16 ink4a-siRNA-loaded nanoparticles increases amyloid-β clearance in animal models of Alzheimer's disease. Mol Neurodegener 2024; 19:25. [PMID: 38493185 PMCID: PMC10943801 DOI: 10.1186/s13024-024-00715-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 02/27/2024] [Indexed: 03/18/2024] Open
Abstract
Age-dependent accumulation of amyloid plaques in patients with sporadic Alzheimer's disease (AD) is associated with reduced amyloid clearance. Older microglia have a reduced ability to phagocytose amyloid, so phagocytosis of amyloid plaques by microglia could be regulated to prevent amyloid accumulation. Furthermore, considering the aging-related disruption of cell cycle machinery in old microglia, we hypothesize that regulating their cell cycle could rejuvenate them and enhance their ability to promote more efficient amyloid clearance. First, we used gene ontology analysis of microglia from young and old mice to identify differential expression of cyclin-dependent kinase inhibitor 2A (p16ink4a), a cell cycle factor related to aging. We found that p16ink4a expression was increased in microglia near amyloid plaques in brain tissue from patients with AD and 5XFAD mice, a model of AD. In BV2 microglia, small interfering RNA (siRNA)-mediated p16ink4a downregulation transformed microglia with enhanced amyloid phagocytic capacity through regulated the cell cycle and increased cell proliferation. To regulate microglial phagocytosis by gene transduction, we used poly (D,L-lactic-co-glycolic acid) (PLGA) nanoparticles, which predominantly target microglia, to deliver the siRNA and to control microglial reactivity. Nanoparticle-based delivery of p16ink4a siRNA reduced amyloid plaque formation and the number of aged microglia surrounding the plaque and reversed learning deterioration and spatial memory deficits. We propose that downregulation of p16ink4a in microglia is a promising strategy for the treatment of Alzheimer's disease.
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Affiliation(s)
- Hyo Jung Shin
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Brain Research Institute, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - In Soo Kim
- Department of Medical Science, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Department of Pharmacology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Seung Gyu Choi
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Brain Research Institute, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Kayoung Lee
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Department of Medical Science, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Hyewon Park
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Department of Medical Science, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Juhee Shin
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Department of Medical Science, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Dayoung Kim
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Jaewon Beom
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Yoon Young Yi
- Department of Pediatrics, College of Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea
| | - Deepak Prasad Gupta
- Department of Medicine, College of Medicine, Catholic Kwandong University, Gangneung, Gangwon-Do, Republic of Korea
| | - Gyun Jee Song
- Department of Medicine, College of Medicine, Catholic Kwandong University, Gangneung, Gangwon-Do, Republic of Korea
- Translational Brain Research Center, International St. Mary's Hospital, Catholic Kwandong University, Incheon, Republic of Korea
| | - Won-Suk Chung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, Republic of Korea
| | - Dong Woon Kim
- Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, Daejeon, Republic of Korea.
- Brain Research Institute, Chungnam National University College of Medicine, Daejeon, Republic of Korea.
- Department of Medical Science, Chungnam National University College of Medicine, Daejeon, Republic of Korea.
- Department of Oral Anatomy and Developmental Biology, College of Dentistry Kyung Hee University, Seoul, Republic of Korea.
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4
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Brown GC. Cell death by phagocytosis. Nat Rev Immunol 2024; 24:91-102. [PMID: 37604896 DOI: 10.1038/s41577-023-00921-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2023] [Indexed: 08/23/2023]
Abstract
Cells can die as a consequence of being phagocytosed by other cells - a form of cell death that has been called phagotrophy, cell cannibalism, programmed cell removal and primary phagocytosis. However, these are all different manifestations of cell death by phagocytosis (termed 'phagoptosis' for short). The engulfed cells die as a result of cytotoxic oxidants, peptides and degradative enzymes within acidic phagolysosomes. Cell death by phagocytosis was discovered by Metchnikov in the 1880s, but was neglected until recently. It is now known to contribute to developmental cell death in nematodes, Drosophila and mammals, and is central to innate and adaptive immunity against pathogens. Cell death by phagocytosis mediates physiological turnover of erythrocytes and other leucocytes, making it the most abundant form of cell death in the mammalian body. Immunity against cancer is also partly mediated by macrophage phagocytosis of cancer cells, but cancer cells can also phagocytose host cells and other cancer cells in order to survive. Recent evidence indicates neurodegeneration and other neuropathologies can be mediated by microglial phagocytosis of stressed neurons. Thus, despite cell death by phagocytosis being poorly recognized, it is one of the oldest, commonest and most important forms of cell death.
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Affiliation(s)
- Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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Castro R, Lopes M, De Biase L, Valdez G. Aging spinal cord microglia become phenotypically heterogeneous and preferentially target motor neurons and their synapses. Glia 2024; 72:206-221. [PMID: 37737058 PMCID: PMC10773989 DOI: 10.1002/glia.24470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/07/2023] [Accepted: 09/03/2023] [Indexed: 09/23/2023]
Abstract
Microglia have been found to acquire unique region-dependent deleterious features with age and diseases that contribute to neuronal dysfunction and degeneration in the brain. However, it remains unknown whether microglia exhibit similar phenotypic heterogeneity in the spinal cord. Here, we performed a regional analysis of spinal cord microglia in 3-, 16-, 23-, and 30-month-old mice. Using light and electron microscopy, we discovered that spinal cord microglia acquire an increasingly activated phenotype during the course of aging regardless of regional location. However, aging causes microglia in the ventral but not dorsal horn to lose their spatial organization. Aged ventral horn microglia also aggregate around the somata of motor neurons and increase their contacts with motor synapses, which have been shown to be lost with age. These findings suggest that microglia may affect the ability of motor neurons to receive and relay motor commands during aging. To generate additional insights about aging spinal cord microglia, we performed RNA-sequencing on FACS-isolated microglia from 3-, 18-, 22-, and 29-month-old mice. We found that spinal cord microglia acquire a similar transcriptional identity as those in the brain during aging that includes altered expression of genes with roles in microglia-neuron interactions and inflammation. By 29 months of age, spinal cord microglia exhibit additional and unique transcriptional changes known and predicted to cause senescence and to alter lysosomal and ribosomal regulation. Altogether, this work provides the foundation to target microglia to ameliorate aged-related changes in the spinal cord, and particularly on the motor circuit.
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Affiliation(s)
- Ryan Castro
- Neuroscience Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Mikayla Lopes
- Molecular Biology, Cell Biology & Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Lindsay De Biase
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, Rhode Island, USA
- Department of Neurology, Warren Alpert Medical School of Medicine, Brown University, Providence, USA
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6
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Rusu B, Kukreja B, Wu T, Dan SJ, Feng MY, Kalish BT. Single-Nucleus Profiling Identifies Accelerated Oligodendrocyte Precursor Cell Senescence in a Mouse Model of Down Syndrome. eNeuro 2023; 10:ENEURO.0147-23.2023. [PMID: 37491366 PMCID: PMC10449487 DOI: 10.1523/eneuro.0147-23.2023] [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: 05/03/2023] [Revised: 07/06/2023] [Accepted: 07/10/2023] [Indexed: 07/27/2023] Open
Abstract
Down syndrome (DS), the most common genetic cause of intellectual disability, is associated with lifelong cognitive deficits. However, the mechanisms by which triplication of chromosome 21 genes drive neuroinflammation and cognitive dysfunction are poorly understood. Here, using the Ts65Dn mouse model of DS, we performed an integrated single-nucleus ATAC and RNA-sequencing (snATAC-seq and snRNA-seq) analysis of the adult cortex. We identified cell type-specific transcriptional and chromatin-associated changes in the Ts65Dn cortex, including regulators of neuroinflammation, transcription and translation, myelination, and mitochondrial function. We discovered enrichment of a senescence-associated transcriptional signature in Ts65Dn oligodendrocyte (OL) precursor cells (OPCs) and epigenetic changes consistent with a loss of heterochromatin. We found that senescence is restricted to a subset of OPCs concentrated in deep cortical layers. Treatment of Ts65Dn mice with a senescence-reducing flavonoid rescued cortical OPC proliferation, restored microglial homeostasis, and improved contextual fear memory. Together, these findings suggest that cortical OPC senescence may be an important driver of neuropathology in DS.
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Affiliation(s)
- Bianca Rusu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1A8, Canada
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario M5G 1L7, Canada
| | - Bharti Kukreja
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario M5G 1L7, Canada
| | - Taiyi Wu
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario M5G 1L7, Canada
| | - Sophie J Dan
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario M5G 1L7, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario M5G 1A8, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario M5G 1A8, Canada
| | - Min Yi Feng
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1A8, Canada
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario M5G 1L7, Canada
| | - Brian T Kalish
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1A8, Canada
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, Ontario M5G 1L7, Canada
- Division of Neonatology, Department of Paediatrics, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
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Jury-Garfe N, You Y, Martínez P, Redding-Ochoa J, Karahan H, Johnson TS, Zhang J, Kim J, Troncoso JC, Lasagna-Reeves CA. Enhanced microglial dynamics and paucity of tau seeding in the amyloid plaque microenvironment contributes to cognitive resilience in Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.27.550884. [PMID: 37546928 PMCID: PMC10402121 DOI: 10.1101/2023.07.27.550884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Asymptomatic Alzheimer's disease (AsymAD) describes the status of subjects with preserved cognition but with identifiable Alzheimer's disease (AD) brain pathology (i.e. Aβ-amyloid deposits, neuritic plaques, and neurofibrillary tangles) at autopsy. In this study, we investigated the postmortem brains of a cohort of AsymAD cases to gain insight into the underlying mechanisms of resilience to AD pathology and cognitive decline. Our results showed that AsymAD cases exhibit an enrichment of core plaques and decreased filamentous plaque accumulation, as well as an increase in microglia surrounding this last type. In AsymAD cases we found less pathological tau aggregation in dystrophic neurites compared to AD and tau seeding activity comparable to healthy control subjects. We used spatial transcriptomics to further characterize the plaque niche and found autophagy, endocytosis, and phagocytosis within the top upregulated pathways in the AsymAD plaque niche, but not in AD. Furthermore, we found ARP2, an actin-based motility protein crucial to initiate the formation of new actin filaments, increased within microglia in the proximity of amyloid plaques in AsymAD. Our findings support that the amyloid-plaque microenvironment in AsymAD cases is characterized by microglia with highly efficient actin-based cell motility mechanisms and decreased tau seeding compared to AD. These two mechanisms can potentially provide protection against the toxic cascade initiated by Aβ that preserves brain health and slows down the progression of AD pathology.
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Affiliation(s)
- Nur Jury-Garfe
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yanwen You
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Pablo Martínez
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Javier Redding-Ochoa
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Hande Karahan
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, USA
| | - Travis S. Johnson
- Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, USA
| | - Jie Zhang
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jungsu Kim
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, USA
| | - Juan C. Troncoso
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Cristian A. Lasagna-Reeves
- Stark Neuroscience Research Institute, Indiana University, Indianapolis, USA
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
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Macaron G, Larochelle C, Arbour N, Galmard M, Girard JM, Prat A, Duquette P. Impact of aging on treatment considerations for multiple sclerosis patients. Front Neurol 2023; 14:1197212. [PMID: 37483447 PMCID: PMC10361071 DOI: 10.3389/fneur.2023.1197212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/18/2023] [Indexed: 07/25/2023] Open
Abstract
With a rapidly aging global population and improvement of outcomes with newer multiple sclerosis (MS)-specific disease-modifying therapies (DMTs), the epidemiology of MS has shifted to an older than previously described population, with a peak prevalence of the disease seen in the 55-65 years age group. Changes in the pathophysiology of MS appear to be age-dependent. Several studies have identified a consistent phase of disability worsening around the fifth decade of life. The latter appears to be independent of prior disease duration and inflammatory activity and concomitant to pathological changes from acute focal active demyelination to chronic smoldering plaques, slow-expanding lesions, and compartmentalized inflammation within the central nervous system (CNS). On the other hand, decreased CNS tissue reserve and poorer remyelinating capacity with aging lead to loss of relapse recovery potential. Aging with MS may imply longer exposure to DMTs, although treatment efficacy in patients >55 years has not been evaluated in pivotal randomized controlled trials and appears to decrease with age. Older individuals are more prone to adverse effects of DMTs, an important aspect of treatment individualization. Aging with MS also implies a higher global burden of comorbid illnesses that contribute to overall impairments and represent a crucial confounder in interpreting clinical worsening. Discontinuation of DMTs after age 55, when no evidence of clinical or radiological activity is detected, is currently under the spotlight. In this review, we will discuss the impact of aging on MS pathobiology, the effect of comorbidities and other confounders on clinical worsening, and focus on current therapeutic considerations in this age group.
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Affiliation(s)
- Gabrielle Macaron
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Faculté de Médecine, Université Saint-Joseph de Beyrouth, Beirut, Lebanon
| | - Catherine Larochelle
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Nathalie Arbour
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Manon Galmard
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Jean Marc Girard
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Alexandre Prat
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
| | - Pierre Duquette
- Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, QC, Canada
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9
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Murray CJ, Vecchiarelli HA, Tremblay MÈ. Enhancing axonal myelination in seniors: A review exploring the potential impact cannabis has on myelination in the aged brain. Front Aging Neurosci 2023; 15:1119552. [PMID: 37032821 PMCID: PMC10073480 DOI: 10.3389/fnagi.2023.1119552] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/22/2023] [Indexed: 04/11/2023] Open
Abstract
Consumption of cannabis is on the rise as public opinion trends toward acceptance and its consequent legalization. Specifically, the senior population is one of the demographics increasing their use of cannabis the fastest, but research aimed at understanding cannabis' impact on the aged brain is still scarce. Aging is characterized by many brain changes that slowly alter cognitive ability. One process that is greatly impacted during aging is axonal myelination. The slow degradation and loss of myelin (i.e., demyelination) in the brain with age has been shown to associate with cognitive decline and, furthermore, is a common characteristic of numerous neurological diseases experienced in aging. It is currently not known what causes this age-dependent degradation, but it is likely due to numerous confounding factors (i.e., heightened inflammation, reduced blood flow, cellular senescence) that impact the many cells responsible for maintaining overall homeostasis and myelin integrity. Importantly, animal studies using non-human primates and rodents have also revealed demyelination with age, providing a reliable model for researchers to try and understand the cellular mechanisms at play. In rodents, cannabis was recently shown to modulate the myelination process. Furthermore, studies looking at the direct modulatory impact cannabis has on microglia, astrocytes and oligodendrocyte lineage cells hint at potential mechanisms to prevent some of the more damaging activities performed by these cells that contribute to demyelination in aging. However, research focusing on how cannabis impacts myelination in the aged brain is lacking. Therefore, this review will explore the evidence thus far accumulated to show how cannabis impacts myelination and will extrapolate what this knowledge may mean for the aged brain.
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Affiliation(s)
- Colin J. Murray
- Neuroscience Graduate Program, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- *Correspondence: Colin J. Murray,
| | | | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Départment de Médicine Moléculaire, Université Laval, Québec City, QC, Canada
- Axe Neurosciences, Center de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montréal, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- Institute for Aging and Lifelong Health, University of Victoria, Victoria, BC, Canada
- Marie-Ève Tremblay,
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Modulation of the Microglial Nogo-A/NgR Signaling Pathway as a Therapeutic Target for Multiple Sclerosis. Cells 2022; 11:cells11233768. [PMID: 36497029 PMCID: PMC9737582 DOI: 10.3390/cells11233768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Current therapeutics targeting chronic phases of multiple sclerosis (MS) are considerably limited in reversing the neural damage resulting from repeated inflammation and demyelination insults in the multi-focal lesions. This inflammation is propagated by the activation of microglia, the endogenous immune cell aiding in the central nervous system homeostasis. Activated microglia may transition into polarized phenotypes; namely, the classically activated proinflammatory phenotype (previously categorized as M1) and the alternatively activated anti-inflammatory phenotype (previously, M2). These transitional microglial phenotypes are dynamic states, existing as a continuum. Shifting microglial polarization to an anti-inflammatory status may be a potential therapeutic strategy that can be harnessed to limit neuroinflammation and further neurodegeneration in MS. Our research has observed that the obstruction of signaling by inhibitory myelin proteins such as myelin-associated inhibitory factor, Nogo-A, with its receptor (NgR), can regulate microglial cell function and activity in pre-clinical animal studies. Our review explores the microglial role and polarization in MS pathology. Additionally, the potential therapeutics of targeting Nogo-A/NgR cellular mechanisms on microglia migration, polarization and phagocytosis for neurorepair in MS and other demyelination diseases will be discussed.
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Abukanna AMA, AlAnazi FM, AlAnazi ZM, AlAnazi FAL, AlAnaz AHO, AlAnazi RML. Aging and Changes in White Blood Cells Count and Immunity: A Systematic Review. CLINICAL CANCER INVESTIGATION JOURNAL 2022. [DOI: 10.51847/kcawdh6o97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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