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Granholm AC, Hamlett ED. The Role of Tau Pathology in Alzheimer's Disease and Down Syndrome. J Clin Med 2024; 13:1338. [PMID: 38592182 PMCID: PMC10932364 DOI: 10.3390/jcm13051338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/10/2024] [Accepted: 02/20/2024] [Indexed: 04/10/2024] Open
Abstract
Background: Individuals with Down syndrome (DS) exhibit an almost complete penetrance of Alzheimer's disease (AD) pathology but are underrepresented in clinical trials for AD. The Tau protein is associated with microtubule function in the neuron and is crucial for normal axonal transport. In several different neurodegenerative disorders, Tau misfolding leads to hyper-phosphorylation of Tau (p-Tau), which may seed pathology to bystander cells and spread. This review is focused on current findings regarding p-Tau and its potential to seed pathology as a "prion-like" spreader. It also considers the consequences of p-Tau pathology leading to AD, particularly in individuals with Down syndrome. Methods: Scopus (SC) and PubMed (PM) were searched in English using keywords "tau AND seeding AND brain AND down syndrome". A total of 558 SC or 529 PM potentially relevant articles were identified, of which only six SC or three PM articles mentioned Down syndrome. This review was built upon the literature and the recent findings of our group and others. Results: Misfolded p-Tau isoforms are seeding competent and may be responsible for spreading AD pathology. Conclusions: This review demonstrates recent work focused on understanding the role of neurofibrillary tangles and monomeric/oligomeric Tau in the prion-like spreading of Tau pathology in the human brain.
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Affiliation(s)
- Ann-Charlotte Granholm
- Department of Neurosurgery, University of Colorado Anschutz Medical Center, Aurora, CO 80045, USA
| | - Eric D. Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
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2
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Chmiel J, Rybakowski F, Leszek J. EEG in Down Syndrome-A Review and Insights into Potential Neural Mechanisms. Brain Sci 2024; 14:136. [PMID: 38391711 PMCID: PMC10886507 DOI: 10.3390/brainsci14020136] [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: 12/17/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
Introduction: Down syndrome (DS) stands out as one of the most prevalent genetic disorders, imposing a significant burden on both society and the healthcare system. Scientists are making efforts to understand the neural mechanisms behind the pathophysiology of this disorder. Among the valuable methods for studying these mechanisms is electroencephalography (EEG), a non-invasive technique that measures the brain's electrical activity, characterised by its excellent temporal resolution. This review aims to consolidate studies examining EEG usage in individuals with DS. The objective was to identify shared elements of disrupted EEG activity and, crucially, to elucidate the neural mechanisms underpinning these deviations. Searches were conducted on Pubmed/Medline, Research Gate, and Cochrane databases. Results: The literature search yielded 17 relevant articles. Despite the significant time span, small sample size, and overall heterogeneity of the included studies, three common features of aberrant EEG activity in people with DS were found. Potential mechanisms for this altered activity were delineated. Conclusions: The studies included in this review show altered EEG activity in people with DS compared to the control group. To bolster these current findings, future investigations with larger sample sizes are imperative.
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Affiliation(s)
- James Chmiel
- Institute of Neurofeedback and tDCS Poland, 70-393 Szczecin, Poland
| | - Filip Rybakowski
- Department and Clinic of Psychiatry, Poznan University of Medical Sciences, 61-701 Poznań, Poland
| | - Jerzy Leszek
- Department and Clinic of Psychiatry, Wrocław Medical University, 54-235 Wrocław, Poland
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3
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O’Boyle NM, Helesbeux JJ, Meegan MJ, Sasse A, O’Shaughnessy E, Qaisar A, Clancy A, McCarthy F, Marchand P. 30th Annual GP2A Medicinal Chemistry Conference. Pharmaceuticals (Basel) 2023; 16:ph16030432. [PMID: 36986531 PMCID: PMC10056312 DOI: 10.3390/ph16030432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/16/2023] [Indexed: 03/14/2023] Open
Abstract
The Group for the Promotion of Pharmaceutical Chemistry in Academia (GP2A) held their 30th annual conference in August 2022 in Trinity College Dublin, Ireland. There were 9 keynote presentations, 10 early career researcher presentations and 41 poster presentations.
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Affiliation(s)
- Niamh M. O’Boyle
- School of Pharmacy and Pharmaceutical Sciences, Panoz Institute and Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 PN40 Dublin, Ireland
- Correspondence: ; Tel.: +353-1896-2524
| | | | - Mary J. Meegan
- School of Pharmacy and Pharmaceutical Sciences, Panoz Institute and Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Astrid Sasse
- School of Pharmacy and Pharmaceutical Sciences, Panoz Institute and Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Elizabeth O’Shaughnessy
- School of Pharmacy and Pharmaceutical Sciences, Panoz Institute and Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Alina Qaisar
- School of Pharmacy and Pharmaceutical Sciences, Panoz Institute and Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Aoife Clancy
- School of Pharmacy and Pharmaceutical Sciences, Panoz Institute and Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Florence McCarthy
- School of Chemistry and ABCRF, University College Cork, T12 K8AF Cork, Ireland
| | - Pascal Marchand
- Cibles et Médicaments des Infections et de l’Immunité, IICiMed, Nantes Université, UR 1155, F-44000 Nantes, France
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4
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Tsang W, Oliver D, Triantafyllopoulou P. Quality of life measurement tools for people with dementia and intellectual disabilities: A systematic review. JOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES 2022; 36:28-38. [PMID: 36380473 PMCID: PMC10099806 DOI: 10.1111/jar.13050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/15/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Adults with intellectual disabilities are an at-risk group of developing dementia. In the absence of a cure for dementia, emphasis on treatment is the promotion of Quality of life (QoL). The aim of this review is to identify and describe QoL tools for people with intellectual disabilities and dementia. METHOD A systematic review was carried out using 10 databases and papers from up to March year 2021. RESULTS Two instruments were identified and examined. The QoL in late-stage dementia, which showed evidence of good levels of internal consistency, intra-rater reliability, test-retest reliability, and convergent validity. The Dementia Quality of Life - proxy was also used; however, its psychometric properties have yet to be studied within the intellectual disabilities population. CONCLUSION It is recommended instruments should be developed and psychometrically tested specifically for adults with intellectual disabilities and dementia to help inform policy makers, measure outcomes of interventions and personal outcomes.
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Affiliation(s)
- Winnie Tsang
- School of Social Policy, Sociology and Social Research, Tizard Centre University of Kent Canterbury UK
| | - David Oliver
- School of Social Policy, Sociology and Social Research, Tizard Centre University of Kent Canterbury UK
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5
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Nübling G, Wagemann O, Loosli SV, Wlasich E, Danek A, Levin J. [Diagnosing Alzheimer Dementia in People with Down Syndrome in Accordance with ICD, DSM V and A/T/N System]. FORTSCHRITTE DER NEUROLOGIE-PSYCHIATRIE 2022; 90:416-420. [PMID: 35320851 DOI: 10.1055/a-1771-6273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Due to a triplication of the amyloid precursor protein (APP) gene on chromosome 21, most people with Down's Syndrome (DS) are at high risk of developing an Alzheimer type of dementia associated with Down's Syndrome (DS-AD). The diagnostic process of DS-AD is challenging due to the high variability of symptoms ranging from memory deficits to social withdrawal or aggression, as well as a broad spectrum of differential diagnoses. Currently, ICD-10, DSM-V and the novel A(amyloid)/T(tau)/N (neurodegeneration) system are available for classifying dementia, although DS-AD is not represented as a specific entity in any of these systems. Here, we discuss challenges in arriving at a diagnosis of Alzheimer dementia in people with DS in accordance with these diagnostic systems.
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Affiliation(s)
- Georg Nübling
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Standort München, Germany
| | - Olivia Wagemann
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Standort München, Germany
| | - Sandra V Loosli
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, Germany
| | - Elisabeth Wlasich
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, Germany
| | - Adrian Danek
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, Germany
| | - Johannes Levin
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Standort München, Germany.,Munich Cluster for Systems Neurology (SyNergy), München, Germany
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6
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Martinez JL, Zammit MD, West NR, Christian BT, Bhattacharyya A. Basal Forebrain Cholinergic Neurons: Linking Down Syndrome and Alzheimer's Disease. Front Aging Neurosci 2021; 13:703876. [PMID: 34322015 PMCID: PMC8311593 DOI: 10.3389/fnagi.2021.703876] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/17/2021] [Indexed: 12/31/2022] Open
Abstract
Down syndrome (DS, trisomy 21) is characterized by intellectual impairment at birth and Alzheimer's disease (AD) pathology in middle age. As individuals with DS age, their cognitive functions decline as they develop AD pathology. The susceptibility to degeneration of a subset of neurons, known as basal forebrain cholinergic neurons (BFCNs), in DS and AD is a critical link between cognitive impairment and neurodegeneration in both disorders. BFCNs are the primary source of cholinergic innervation to the cerebral cortex and hippocampus, as well as the amygdala. They play a critical role in the processing of information related to cognitive function and are directly engaged in regulating circuits of attention and memory throughout the lifespan. Given the importance of BFCNs in attention and memory, it is not surprising that these neurons contribute to dysfunctional neuronal circuitry in DS and are vulnerable in adults with DS and AD, where their degeneration leads to memory loss and disturbance in language. BFCNs are thus a relevant cell target for therapeutics for both DS and AD but, despite some success, efforts in this area have waned. There are gaps in our knowledge of BFCN vulnerability that preclude our ability to effectively design interventions. Here, we review the role of BFCN function and degeneration in AD and DS and identify under-studied aspects of BFCN biology. The current gaps in BFCN relevant imaging studies, therapeutics, and human models limit our insight into the mechanistic vulnerability of BFCNs in individuals with DS and AD.
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Affiliation(s)
- Jose L. Martinez
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States
- Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Matthew D. Zammit
- Waisman Center, University of Wisconsin, Madison, WI, United States
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Nicole R. West
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States
- Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Bradley T. Christian
- Waisman Center, University of Wisconsin, Madison, WI, United States
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin, Madison, WI, United States
- Department of Cellular and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
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7
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Chrétien B, Jourdan JP, Davis A, Fedrizzi S, Bureau R, Sassier M, Rochais C, Alexandre J, Lelong-Boulouard V, Dolladille C, Dallemagne P. Disproportionality analysis in VigiBase as a drug repositioning method for the discovery of potentially useful drugs in Alzheimer's disease. Br J Clin Pharmacol 2020; 87:2830-2837. [PMID: 33274491 DOI: 10.1111/bcp.14690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/09/2020] [Accepted: 11/28/2020] [Indexed: 12/12/2022] Open
Abstract
Drug repositioning aims to propose new indications for marketed drugs. Although several methods exist, the utility of pharmacovigilance databases for this purpose is unclear. We conducted a disproportionality analysis in the World Health Organization pharmacovigilance database VigiBase to identify potential anticholinesterase drug candidates for repositioning in Alzheimer's disease (AD). METHODS Disproportionality analysis is a validated method for detecting significant associations between drugs and adverse events (AEs) in pharmacovigilance databases. We applied this approach in VigiBase to establish the safety profile displayed by the anticholinesterase drugs used in AD and searched the database for drugs with similar safety profiles. The detected drugs with potential activity against acetylcholinesterase and butyrylcholinesterases (BuChEs) were then evaluated to confirm their anticholinesterase potential. RESULTS We identified 22 drugs with safety profiles similar to AD medicines. Among these drugs, 4 (clozapine, aripiprazole, sertraline and S-duloxetine) showed a human BuChE inhibition rate of over 70% at 10-5 M. Their human BuChE half maximal inhibitory concentration values were compatible with clinical anticholinesterase action in humans at their normal doses. The most active human BuChE inhibitor in our study was S-duloxetine, with a half maximal inhibitory concentration of 1.2 μM. Combined with its ability to inhibit serotonin (5-HT) reuptake, the use of this drug could represent a novel multitarget directed ligand therapeutic strategy for AD. CONCLUSION We identified 4 drugs with repositioning potential in AD using drug safety profiles derived from a pharmacovigilance database. This method could be useful for future drug repositioning efforts.
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Affiliation(s)
- Basile Chrétien
- Department of Pharmacology, Caen University Hospital, Caen, F-14000, France.,Pharmacovigilance Regional Center, Caen University Hospital, Caen, F-14000, France
| | - Jean-Pierre Jourdan
- Department of Pharmacy, Caen University Hospital, Caen, F-14000, France.,Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), Normandie Univ, UNICAEN, Caen, F-14000, France
| | - Audrey Davis
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), Normandie Univ, UNICAEN, Caen, F-14000, France
| | - Sophie Fedrizzi
- Department of Pharmacology, Caen University Hospital, Caen, F-14000, France.,Pharmacovigilance Regional Center, Caen University Hospital, Caen, F-14000, France
| | - Ronan Bureau
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), Normandie Univ, UNICAEN, Caen, F-14000, France
| | - Marion Sassier
- Department of Pharmacology, Caen University Hospital, Caen, F-14000, France.,Pharmacovigilance Regional Center, Caen University Hospital, Caen, F-14000, France
| | - Christophe Rochais
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), Normandie Univ, UNICAEN, Caen, F-14000, France
| | - Joachim Alexandre
- Department of Pharmacology, Caen University Hospital, Caen, F-14000, France.,Pharmacovigilance Regional Center, Caen University Hospital, Caen, F-14000, France.,EA4650, Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, Normandie Univ, UNICAEN, Caen, 14000, France
| | - Véronique Lelong-Boulouard
- Department of Pharmacology, Caen University Hospital, Caen, F-14000, France.,INSERM UMR 1075, COMETE-MOBILITES "Vieillissement, Pathologie, Santé", Normandie Univ, UNICAEN, Caen, 14000, France
| | - Charles Dolladille
- Department of Pharmacology, Caen University Hospital, Caen, F-14000, France.,EA4650, Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, Normandie Univ, UNICAEN, Caen, 14000, France
| | - Patrick Dallemagne
- Centre d'Etudes et de Recherche sur le Médicament de Normandie (CERMN), Normandie Univ, UNICAEN, Caen, F-14000, France
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8
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Santoro JD, Pagarkar D, Chu DT, Rosso M, Paulsen KC, Levitt P, Rafii MS. Neurologic complications of Down syndrome: a systematic review. J Neurol 2020; 268:4495-4509. [PMID: 32920658 DOI: 10.1007/s00415-020-10179-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 12/18/2022]
Abstract
Down syndrome (DS) is one of the most well-recognized genetic disorders. Persons with DS are known to have a variety of co-morbid medical problems, affecting nearly all organ systems. Improved healthcare interventions and research have allowed for increased life span of persons with DS, although disorders of the neurologic system remain underexplored. The purpose of this systematic review is to provide clinically pertinent information on the neurological phenotypes of frequently occurring or clinically relevant conditions. A retrospective review of MEDLINE, Scopus, and Pubmed were used to identify sources among seventeen, clinically relevant, search categories. MeSH terms all contained the phrase "Down Syndrome" in conjunction with the topic of interest. 'Frequently-occurring' was defined as prevalent in more than 10% of persons with DS across their lifespan, whereas 'clinically-relevant' was defined as a disease condition where early diagnosis or intervention can augment the disease course. In total, 4896 sources were identified with 159 sources meeting criteria for inclusion. Seventeen clinical conditions were grouped under the following subjects: hypotonia, intellectual and learning disability, cervical instability, autism spectrum disorder, epilepsy, cerebrovascular disease, Alzheimer's disease and neuropsychiatric disease. The results of this review provide a blueprint for the clinical neurologist taking care of persons with DS across the age spectrum and indicate that there are many underrecognized and misdiagnosed co-occurring conditions in DS, highlighting the need for further research.
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Affiliation(s)
- Jonathan D Santoro
- Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA. .,Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
| | - Dania Pagarkar
- Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Duong T Chu
- Faculty of Medicine, Queen's University, Kingston, ON, Canada
| | - Mattia Rosso
- Department of Neurology, Medical University of South Carolina, Charleston, SC, USA
| | - Kelli C Paulsen
- Division of Neurology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Pat Levitt
- Department of Pediatrics and Program in Developmental Neuroscience and Developmental Neurogenetics, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Michael S Rafii
- Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA.,Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Alzheimer's Therapeutic Research Institute (ATRI), Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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9
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Antonarakis SE, Skotko BG, Rafii MS, Strydom A, Pape SE, Bianchi DW, Sherman SL, Reeves RH. Down syndrome. Nat Rev Dis Primers 2020; 6:9. [PMID: 32029743 PMCID: PMC8428796 DOI: 10.1038/s41572-019-0143-7] [Citation(s) in RCA: 349] [Impact Index Per Article: 87.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/17/2019] [Indexed: 12/11/2022]
Abstract
Trisomy 21, the presence of a supernumerary chromosome 21, results in a collection of clinical features commonly known as Down syndrome (DS). DS is among the most genetically complex of the conditions that are compatible with human survival post-term, and the most frequent survivable autosomal aneuploidy. Mouse models of DS, involving trisomy of all or part of human chromosome 21 or orthologous mouse genomic regions, are providing valuable insights into the contribution of triplicated genes or groups of genes to the many clinical manifestations in DS. This endeavour is challenging, as there are >200 protein-coding genes on chromosome 21 and they can have direct and indirect effects on homeostasis in cells, tissues, organs and systems. Although this complexity poses formidable challenges to understanding the underlying molecular basis for each of the many clinical features of DS, it also provides opportunities for improving understanding of genetic mechanisms underlying the development and function of many cell types, tissues, organs and systems. Since the first description of trisomy 21, we have learned much about intellectual disability and genetic risk factors for congenital heart disease. The lower occurrence of solid tumours in individuals with DS supports the identification of chromosome 21 genes that protect against cancer when overexpressed. The universal occurrence of the histopathology of Alzheimer disease and the high prevalence of dementia in DS are providing insights into the pathology and treatment of Alzheimer disease. Clinical trials to ameliorate intellectual disability in DS signal a new era in which therapeutic interventions based on knowledge of the molecular pathophysiology of DS can now be explored; these efforts provide reasonable hope for the future.
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Affiliation(s)
- Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland.
| | - Brian G Skotko
- Down Syndrome Program, Division of Medical Genetics, Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Michael S Rafii
- Keck School of Medicine of University of Southern California, California, CA, USA
| | - Andre Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Sarah E Pape
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Diana W Bianchi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Stephanie L Sherman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Roger H Reeves
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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10
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Rafii MS, Santoro SL. Prevalence and Severity of Alzheimer Disease in Individuals With Down Syndrome. JAMA Neurol 2019; 76:142-143. [PMID: 30452497 DOI: 10.1001/jamaneurol.2018.3443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Michael S Rafii
- Alzheimer's Therapeutic Research Institute, Keck School of Medicine of the University of Southern California, San Diego
| | - Stephanie L Santoro
- Down Syndrome Program, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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11
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Rueda N, Flórez J, Dierssen M, Martínez-Cué C. Translational validity and implications of pharmacotherapies in preclinical models of Down syndrome. PROGRESS IN BRAIN RESEARCH 2019; 251:245-268. [PMID: 32057309 DOI: 10.1016/bs.pbr.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neurodevelopmental disorders are challenging to study in the laboratory, and despite a large investment, few novel treatments have been developed in the last decade. While animal models have been valuable in elucidating disease mechanisms and in providing insights into the function of specific genes, the predictive validity of preclinical models to test potential therapies has been questioned. In the last two decades, diverse new murine models of Down syndrome (DS) have been developed and numerous studies have demonstrated neurobiological alterations that could be responsible for the cognitive and behavioral phenotypes found in this syndrome. In many cases, similar alterations were found in murine models and in individuals with DS, although several phenotypes shown in animals have yet not been confirmed in the human condition. Some of the neurobiological alterations observed in mice have been proposed to account for their changes in cognition and behavior, and have received special attention because of being putative therapeutic targets. Those include increased oxidative stress, altered neurogenesis, overexpression of the Dyrk1A gene, GABA-mediated overinhibition and Alzheimer's disease-related neurodegeneration. Subsequently, different laboratories have tested the efficacy of pharmacotherapies targeting these alterations. Unfortunately, animal models are limited in their ability to mimic the extremely complex process of human neurodevelopment and neuropathology. Therefore, the safety and efficacy identified in animal studies are not always translated to humans, and most of the drugs tested have not demonstrated any positive effect or very limited efficacy in clinical trials. Despite their limitations, though, animal trials give us extremely valuable information for developing and testing drugs for human use that cannot be obtained from molecular or cellular experiments alone. This chapter reviews some of these therapeutic approaches and discusses some reasons that could account for the discrepancy between the findings in mouse models of DS and in humans, including: (i) the incomplete resemble of the genetic alterations of available mouse models of DS and human trisomy 21, (ii) the lack of evidence that some of the phenotypic alterations found in mice (e.g., GABA-mediated overinhibition, and alterations in adult neurogenesis) are also present in DS individuals, and (iii) the inaccuracy and/or inadequacy of the methods used in clinical trials to detect changes in the cognitive and behavioral functions of people with DS. Despite the shortcomings of animal models, animal experimentation remains an invaluable tool in developing drugs. Thus, we will also discuss how to increase predictive validity of mouse models.
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Affiliation(s)
- Noemí Rueda
- Department of Physiology and Pharmacology, University of Cantabria, Santander, Spain
| | - Jesús Flórez
- Department of Physiology and Pharmacology, University of Cantabria, Santander, Spain
| | - Mara Dierssen
- Cellular and Systems Neurobiology, Systems Biology Program, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Carmen Martínez-Cué
- Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain.
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12
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Baburamani AA, Patkee PA, Arichi T, Rutherford MA. New approaches to studying early brain development in Down syndrome. Dev Med Child Neurol 2019; 61:867-879. [PMID: 31102269 PMCID: PMC6618001 DOI: 10.1111/dmcn.14260] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/28/2019] [Indexed: 12/19/2022]
Abstract
Down syndrome is the most common genetic developmental disorder in humans and is caused by partial or complete triplication of human chromosome 21 (trisomy 21). It is a complex condition which results in multiple lifelong health problems, including varying degrees of intellectual disability and delays in speech, memory, and learning. As both length and quality of life are improving for individuals with Down syndrome, attention is now being directed to understanding and potentially treating the associated cognitive difficulties and their underlying biological substrates. These have included imaging and postmortem studies which have identified decreased regional brain volumes and histological anomalies that accompany early onset dementia. In addition, advances in genome-wide analysis and Down syndrome mouse models are providing valuable insight into potential targets for intervention that could improve neurogenesis and long-term cognition. As little is known about early brain development in human Down syndrome, we review recent advances in magnetic resonance imaging that allow non-invasive visualization of brain macro- and microstructure, even in utero. It is hoped that together these advances may enable Down syndrome to become one of the first genetic disorders to be targeted by antenatal treatments designed to 'normalize' brain development. WHAT THIS PAPER ADDS: Magnetic resonance imaging can provide non-invasive characterization of early brain development in Down syndrome. Down syndrome mouse models enable study of underlying pathology and potential intervention strategies. Potential therapies could modify brain structure and improve early cognitive levels. Down syndrome may be the first genetic disorder to have targeted therapies which alter antenatal brain development.
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Affiliation(s)
- Ana A Baburamani
- Centre for the Developing BrainDepartment of Perinatal Imaging and HealthSchool of Biomedical Engineering & Imaging SciencesKing's College LondonKing's Health PartnersSt Thomas’ HospitalLondonUK
| | - Prachi A Patkee
- Centre for the Developing BrainDepartment of Perinatal Imaging and HealthSchool of Biomedical Engineering & Imaging SciencesKing's College LondonKing's Health PartnersSt Thomas’ HospitalLondonUK
| | - Tomoki Arichi
- Centre for the Developing BrainDepartment of Perinatal Imaging and HealthSchool of Biomedical Engineering & Imaging SciencesKing's College LondonKing's Health PartnersSt Thomas’ HospitalLondonUK,Department of BioengineeringImperial College LondonLondonUK,Children's NeurosciencesEvelina London Children's HospitalLondonUK
| | - Mary A Rutherford
- Centre for the Developing BrainDepartment of Perinatal Imaging and HealthSchool of Biomedical Engineering & Imaging SciencesKing's College LondonKing's Health PartnersSt Thomas’ HospitalLondonUK
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Hithersay R, Startin CM, Hamburg S, Mok KY, Hardy J, Fisher EMC, Tybulewicz VLJ, Nizetic D, Strydom A. Association of Dementia With Mortality Among Adults With Down Syndrome Older Than 35 Years. JAMA Neurol 2019; 76:152-160. [PMID: 30452522 PMCID: PMC6439956 DOI: 10.1001/jamaneurol.2018.3616] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/20/2018] [Indexed: 01/30/2023]
Abstract
Importance This work quantifies the fatal burden of dementia associated with Alzheimer disease in individuals with Down syndrome (DS). Objective To explore the association of dementia associated with Alzheimer disease with mortality and examine factors associated with dementia in adults with DS. Design, Settings and Participants Prospective longitudinal study in a community setting in England. Data collection began March 29, 2012. Cases were censored on December 13, 2017. The potential sample consisted of all adults 36 years and older from the London Down Syndrome Consortium cohort with 2 data times and dementia status recorded (N = 300); 6 withdrew from study, 28 were lost to follow-up, and 55 had a single data collection point at time of analysis. The final sample consisted of 211 participants, with 503.92 person-years' follow-up. Exposures Dementia status, age, sex, APOE genotype, level of intellectual disability, health variables, and living situation. Main Outcomes and Measures Crude mortality rates, time to death, and time to dementia diagnosis with proportional hazards of predictors. Results Of the 211 participants, 96 were women (45.5%) and 66 (31.3%) had a clinical dementia diagnosis. Twenty-seven participants (11 female; mean age at death, 56.74 years) died during the study period. Seventy percent had dementia. Crude mortality rates for individuals with dementia (1191.85 deaths per 10 000 person-years; 95% CI, 1168.49-1215.21) were 5 times higher than for those without (232.22 deaths per 10 000 person-years; 95% CI, 227.67-236.77). For those with dementia, APOE ε4 carriers had a 7-fold increased risk of death (hazard ratio [HR], 6.91; 95% CI, 1.756-27.195). For those without dementia, epilepsy with onset after age 36 years was associated with mortality (HR, 9.66; 95% CI, 1.59-58.56). APOE ε4 carriers (HR, 4.91; 95% CI, 2.53-9.56), adults with early-onset epilepsy (HR, 3.61; 95% CI, 1.12-11.60), multiple health comorbidities (HR, 1.956; 95% CI, 1.087-3.519), and those living with family (HR, 2.14; 95% CI, 1.08-4.20) received significantly earlier dementia diagnoses. Conclusions and Relevance Dementia was associated with mortality in 70% of older adults with DS. APOE ε4 carriers and/or people with multiple comorbid health conditions were at increased risk of dementia and death, highlighting the need for good health care. For those who died without a dementia diagnosis, late-onset epilepsy was the only significant factor associated with death, raising questions about potentially undiagnosed dementia cases in this group.
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Affiliation(s)
- Rosalyn Hithersay
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, England
- Division of Psychiatry, University College London, London, England
- London Down Syndrome Consortium, London, England
| | - Carla M. Startin
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, England
- Division of Psychiatry, University College London, London, England
- London Down Syndrome Consortium, London, England
| | - Sarah Hamburg
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, England
- Division of Psychiatry, University College London, London, England
- London Down Syndrome Consortium, London, England
| | - Kin Y. Mok
- London Down Syndrome Consortium, London, England
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, England
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, Special Administrative Region of China
| | - John Hardy
- London Down Syndrome Consortium, London, England
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, England
- Reta Lila Weston Institute, Institute of Neurology, University College London, London, England
| | - Elizabeth M. C. Fisher
- London Down Syndrome Consortium, London, England
- Department of Neuromuscular Diseases, Institute of Neurology, University College London, London, England
| | - Victor L. J. Tybulewicz
- London Down Syndrome Consortium, London, England
- The Francis Crick Institute, London, England
- Imperial College, London, England
| | - Dean Nizetic
- London Down Syndrome Consortium, London, England
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
- Blizard Institute, Barts and the London School of Medicine, Queen Mary University of London, London, England
| | - André Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, England
- Division of Psychiatry, University College London, London, England
- London Down Syndrome Consortium, London, England
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Buckley S. A request for clarifications and additional data. Br J Psychiatry 2018; 213:667. [PMID: 30339111 DOI: 10.1192/bjp.2018.193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Sue Buckley
- Psychologist,Down Syndrome Education International and University of Portsmouth,UK.
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Smith D, Chicoine B. Difficulties of diagnosing and managing dementia in people with Down syndrome. Br J Psychiatry 2018; 213:668-669. [PMID: 30339114 DOI: 10.1192/bjp.2018.199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- David Smith
- Physician,Down Syndrome Clinic of Wisconsin,USA
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Abstract
Introduction: Comorbid psychiatric disorders are common in Down syndrome (DS). Evidence for pharmacotherapy of psychiatric co-morbidity in DS is limited. Areas covered: This article reviews the literature on the pharmacotherapy of psychiatric conditions co-occurring with DS, including major depressive disorder (MDD), bipolar disorder, anxiety disorders, obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), psychosis, and catatonia. A section on the phenomenon of regression is included. Expert opinion: For MDD, we typically begin with selective serotonin reuptake inhibitors (SSRIs). For bipolar disorder, we often use carbamazepine. For psychotic symptoms, we begin with risperidone or aripiprazole. We use buspirone to treat anxiety. For obsessional slowness/OCD, we begin with an SSRI. For stereotypical repetitive behavior, we tend to use buspirone. For ADHD, we begin with guanfacine. For irritability of comorbid ASD, we use risperidone or aripiprazole. For dementia in DS, we refer to a neurologist for medical work-up and medication management. We treat catatonia-like 'regression' with lorazepam. If ineffective, we use memantine or clozapine. Electroconvulsive therapy is considered if pharmacotherapy is ineffective. We treat 'regression' with symptoms of MDD ± psychosis, with an antidepressant and an antipsychotic if needed. Randomized controlled trials of medications for comorbid psychiatric disorders in DS are warranted.
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Affiliation(s)
- Michelle L Palumbo
- a Instructor in Pediatrics, Harvard Medical School , Lurie Center for Autism , Lexington , MA , USA
| | - Christopher J McDougle
- b Nancy Lurie Marks Professor in the Field of Autism, Harvard Medical School, Director , Lurie Center for Autism , Lexington , MA , USA
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