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1.
Cereb Cortex ; 33(16): 9639-9651, 2023 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-37401006

RESUMO

Down syndrome (DS) is associated with an ultra-high risk of developing Alzheimer's disease (AD). Understanding variability in pre-AD cognitive abilities may help understand cognitive decline in this population. The mismatch negativity (MMN) is an event-related potential component reflecting the detection of deviant stimuli that is thought to represent underlying memory processes, with reduced MMN amplitudes being associated with cognitive decline. To further understand the MMN in adults with DS without AD, we explored the relationships between MMN, age, and cognitive abilities (memory, language, and attention) in 27 individuals (aged 17-51) using a passive auditory oddball task. Statistically significant MMN was present only in 18 individuals up to 41 years of age and the latency were longer than canonical parameters reported in the literature. Reduced MMN amplitude was associated with lower memory scores, while longer MMN latencies were associated with poorer memory, verbal abilities, and attention. Therefore, the MMN may represent a valuable index of cognitive abilities in DS. In combination with previous findings, we hypothesize that while MMN response and amplitude may be associated with AD-related memory loss, MMN latency may be associated with speech signal processing. Future studies may explore the potential impact of AD on MMN in people with DS.


Assuntos
Doença de Alzheimer , Síndrome de Down , Humanos , Adulto , Eletroencefalografia , Estimulação Acústica , Potenciais Evocados/fisiologia , Cognição , Transtornos da Memória , Potenciais Evocados Auditivos/fisiologia
2.
Alzheimers Dement ; 20(5): 3649-3656, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38480678

RESUMO

Prior authorization criteria for Federal Drug Administration (FDA) approved immunotherapeutics, among the class of anti-amyloid monoclonal antibodies (mAbs), established by state drug formulary committees, are tailored for adults with late-onset Alzheimer's disease. This overlooks adults with Down syndrome (DS), who often experience dementia at a younger age and with different diagnostic assessment outcomes. This exclusion may deny DS adults access to potential disease-modifying treatments. To address this issue, an international expert panel convened to establish adaptations of prescribing criteria suitable for DS patients and parameters for access to Centers for Medicare & Medicaid Services (CMS) registries. The panel proposed mitigating disparities by modifying CMS and payer criteria to account for younger onset age, using alternative language and assessment instruments validated for cognitive decline in the DS population. The panel also recommended enhancing prescribing clinicians' diagnostic capabilities for DS and initiated awareness-raising activities within healthcare organizations. These efforts facilitated discussions with federal officials, aimed at achieving equity in access to anti-amyloid immunotherapeutics, with implications for national authorities worldwide evaluating these and other new disease-modifying therapeutics for Alzheimer's disease.


Assuntos
Síndrome de Down , Humanos , Estados Unidos , Doença de Alzheimer/tratamento farmacológico , Adulto , Anticorpos Monoclonais/uso terapêutico , Imunoterapia/métodos
3.
Alzheimers Dement ; 20(5): 3270-3280, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38506627

RESUMO

INTRODUCTION: People with Down syndrome (DS) have high risk of developing Alzheimer's disease (AD). This study examined mean ages of AD diagnosis and associations with co-occurring conditions among adults with DS from five European countries. METHODS: Data from 1335 people with DS from the Horizon 21 European DS Consortium were used for the analysis. RESULTS: Mean ages of AD diagnosis ranged between 51.4 (SD 7.0) years (United Kingdom) and 55.6 (SD 6.8) years (France). Sleep-related and mental health problems were associated with earlier age of AD diagnosis. The higher number of co-occurring conditions the more likely the person with DS is diagnosed with AD at an earlier age. DISCUSSION: Mean age of AD diagnosis in DS was relatively consistent across countries. However, co-occurring conditions varied and impacted on age of diagnosis, suggesting that improvements can be made in diagnosing and managing these conditions to delay onset of AD in DS. HIGHLIGHTS: Mean age of AD diagnosis was relatively consistent between countries Sleep problems and mental health problems were associated with earlier age of AD diagnosis APOE ε4 carriers were diagnosed with AD at an earlier age compared to non-carriers Number of co-occurring conditions was associated with earlier age of AD diagnosis No differences between level of intellectual disability and mean age of AD diagnosis.


Assuntos
Doença de Alzheimer , Síndrome de Down , Humanos , Síndrome de Down/epidemiologia , Síndrome de Down/diagnóstico , Síndrome de Down/complicações , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/epidemiologia , Masculino , Feminino , Pessoa de Meia-Idade , Europa (Continente)/epidemiologia , Adulto , Reino Unido/epidemiologia , Transtornos do Sono-Vigília/epidemiologia , Transtornos do Sono-Vigília/diagnóstico , Fatores Etários , Idade de Início , França/epidemiologia , Idoso , Comorbidade , Apolipoproteína E4/genética
4.
Neurobiol Dis ; 188: 106336, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38317803

RESUMO

Down syndrome (DS) is one of the most common birth defects and the most prevalent genetic form of intellectual disability. DS arises from trisomy of chromosome 21, but its molecular and pathological consequences are not fully understood. In this study, we compared Dp1Tyb mice, a DS model, against their wild-type (WT) littermates of both sexes to investigate the impact of DS-related genetic abnormalities on the brain phenotype. We performed in vivo whole brain magnetic resonance imaging (MRI) and hippocampal 1H magnetic resonance spectroscopy (MRS) on the animals at 3 months of age. Subsequently, ex vivo MRI scans and histological analyses were conducted post-mortem. Our findings unveiled the following neuroanatomical and biochemical alterations in the Dp1Tyb brains: a smaller surface area and a rounder shape compared to WT brains, with DS males also presenting smaller global brain volume compared with the counterpart WT. Regional volumetric analysis revealed significant changes in 26 out of 72 examined brain regions, including the medial prefrontal cortex and dorsal hippocampus. These alterations were consistently observed in both in vivo and ex vivo imaging data. Additionally, high-resolution ex vivo imaging enabled us to investigate cerebellar layers and hippocampal sub-regions, revealing selective areas of decrease and remodelling in these structures. An analysis of hippocampal metabolites revealed an elevation in glutamine and the glutamine/glutamate ratio in the Dp1Tyb mice compared to controls, suggesting a possible imbalance in the excitation/inhibition ratio. This was accompanied by the decreased levels of taurine. Histological analysis revealed fewer neurons in the hippocampal CA3 and DG layers, along with an increase in astrocytes and microglia. These findings recapitulate multiple neuroanatomical and biochemical features associated with DS, enriching our understanding of the potential connection between chromosome 21 trisomy and the resultant phenotype.


Assuntos
Síndrome de Down , Masculino , Feminino , Camundongos , Animais , Síndrome de Down/patologia , Trissomia/genética , Trissomia/patologia , Glutamina/metabolismo , Encéfalo/metabolismo , Hipocampo/metabolismo , Modelos Animais de Doenças
5.
PLoS Med ; 20(3): e1004117, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36940198

RESUMO

BACKGROUND: Accurate recognition and recording of intellectual disability in those who are admitted to general hospitals is necessary for making reasonable adjustments, ensuring equitable access, and monitoring quality of care. In this study, we determined the rate of recording of intellectual disability in those with the condition who were admitted to hospital and factors associated with the condition being unrecorded. METHODS AND FINDINGS: Retrospective cohort study using 2 linked datasets of routinely collected clinical data in England. We identified adults with diagnosed intellectual disability in a large secondary mental healthcare database and used general hospital records to investigate recording of intellectual disability when people were admitted to general hospitals between 2006 and 2019. Trends over time and factors associated with intellectual disability being unrecorded were investigated. We obtained data on 2,477 adults with intellectual disability who were admitted to a general hospital in England at least once during the study period (total number of admissions = 27,314; median number of admissions = 5). People with intellectual disability were accurately recorded as having the condition during 2.9% (95% CI 2.7% to 3.1%) of their admissions. Broadening the criteria to include a nonspecific code of learning difficulty increased recording to 27.7% (95% CI 27.2% to 28.3%) of all admissions. In analyses adjusted for age, sex, ethnicity, and socioeconomic deprivation, having a mild intellectual disability and being married were associated with increased odds of the intellectual disability being unrecorded in hospital records. We had no measure of quality of hospital care received and could not relate this to the presence or absence of a record of intellectual disability in the patient record. CONCLUSIONS: Recognition and recording of intellectual disability in adults admitted to English general hospitals needs to be improved. Staff awareness training, screening at the point of admission, and data sharing between health and social care services could improve care for people with intellectual disability.


Assuntos
Deficiência Intelectual , Adulto , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/epidemiologia , Hospitais Gerais , Estudos de Coortes , Estudos Retrospectivos , Inglaterra/epidemiologia
6.
Alzheimers Dement ; 19(4): 1383-1392, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36149090

RESUMO

INTRODUCTION: Down syndrome (DS) is associated with immune dysregulation and a high risk of early onset Alzheimer's disease (AD). Complement is a key part of innate immunity and driver of pathological inflammation, including neuroinflammation in AD. Complement dysregulation has been reported in DS; however, the pattern of dysregulation and its relationship to AD risk is unclear. METHODS: Plasma levels of 14 complement biomarkers were measured in 71 adults with DS and 46 controls to identify DS-associated dysregulation; impact of apolipoprotein E (APOE) ε4 genotype, single nucleotide polymorphisms (SNPs) in CLU and CR1, and dementia on complement biomarkers was assessed. RESULTS: Plasma levels of complement activation products (TCC, iC3b), proteins (C1q, C3, C9), and regulators (C1 inhibitor, factor H, FHR4, clusterin) were significantly elevated in DS versus controls while FI and sCR1 were significantly lower. In DS with AD (n = 13), C3 and FI were significantly decreased compared to non-AD DS (n = 58). Neither APOE genotype nor CLU SNPs impacted complement levels, while rs6656401 in CR1 significantly impacted plasma sCR1 levels. CONCLUSIONS: Complement is dysregulated in DS, likely reflecting the generalized immune dysregulation state; measurement may help identify inflammatory events in individuals with DS. Complement biomarkers differed in DS with and without AD and may aid diagnosis and/or prediction. HIGHLIGHTS: Complement is significantly dysregulated in plasma of people with DS who show changes in levels of multiple complement proteins compared to controls. People with DS and dementia show evidence of additional complement dysregulation with significantly lower levels of C3 and factor I compared to those without dementia. rs6656401 in CR1 was associated with significantly elevated sCR1 plasma levels in DS.


Assuntos
Doença de Alzheimer , Síndrome de Down , Adulto , Humanos , Doença de Alzheimer/metabolismo , Síndrome de Down/complicações , Proteínas do Sistema Complemento/genética , Apolipoproteínas E/genética , Apolipoproteína E4/genética , Biomarcadores
7.
Alzheimers Dement ; 19(11): 5129-5137, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37114906

RESUMO

INTRODUCTION: Adults with Down syndrome (DS) are at ultra-high risk of developing Alzheimer's disease (AD), characterized by poor episodic memory and semantic fluency in the preclinical phase in the general population. We explored semantic fluency performance in DS and its relationship to age, AD, and blood biomarkers. METHODS: A total of 302 adults with DS at baseline and 87 at follow-up from the London Down Syndrome Consortium cohort completed neuropsychological assessments. Blood biomarkers were measured with the single molecule array technique in a subset of 94 participants. RESULTS: Poorer verbal fluency performance was observed as age increases. Number of correct words declined in those with AD compared to those without over 2 years and was negatively correlated with neurofilament light (r = -0.37, P = .001) and glial fibrillary acidic protein (r = -0.31, P = .012). DISCUSSION: Semantic fluency may be useful as an early indicator of cognitive decline and provide additional information on AD-related change, showing associations with biomarkers in DS.


Assuntos
Doença de Alzheimer , Síndrome de Down , Adulto , Humanos , Semântica , Doença de Alzheimer/epidemiologia , Síndrome de Down/complicações , Comportamento Verbal , Testes Neuropsicológicos , Transtornos da Memória , Biomarcadores
8.
J Gen Intern Med ; 37(8): 2009-2015, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35386043

RESUMO

BACKGROUND: During the COVID-19 pandemic, people with Down syndrome (DS) have experienced a more severe disease course and higher mortality rates than the general population. It is not yet known whether people with DS are more susceptible to being diagnosed with COVID-19. OBJECTIVE: To explore whether DS is associated with increased susceptibility to COVID-19. DESIGN: Matched-cohort study design using anonymised primary care electronic health records from the May 2021 release of Clinical Practice Research Datalink (CPRD) Aurum. SETTING: Electronic health records from approximately 1400 general practices (GPs) in England. PARTICIPANTS: 8854 people with DS and 34,724 controls matched for age, gender and GP who were registered on or after the 29th January 2020. MEASUREMENTS: The primary outcome was COVID-19 diagnosis between January 2020 and May 2021. Conditional logistic regression models were fitted to estimate associations between DS and COVID-19 diagnosis, adjusting for comorbidities. RESULTS: Compared to controls, people with DS were more likely to be diagnosed with COVID-19 (7.4% vs 5.6%, p ≤ 0.001, odds ratio (OR) = 1.35; 95% CI = 1.23-1.48). There was a significant interaction between people with DS and a chronic respiratory disease diagnosis excluding asthma and increased odds of a COVID-19 diagnosis (OR = 1.71; 95% CI = 1.20-2.43), whilst adjusting for a number of comorbidities. CONCLUSION: Individuals with DS are at increased risk for contracting COVID-19. Those with underlying lung conditions are particularly vulnerable during viral pandemics and should be prioritised for vaccinations.


Assuntos
Asma , COVID-19 , Síndrome de Down , Asma/diagnóstico , Asma/epidemiologia , COVID-19/diagnóstico , COVID-19/epidemiologia , Teste para COVID-19 , Estudos de Coortes , Síndrome de Down/diagnóstico , Síndrome de Down/epidemiologia , Eletrônica , Inglaterra/epidemiologia , Humanos , Pandemias , Atenção Primária à Saúde
9.
Mol Psychiatry ; 26(10): 5766-5788, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-32647257

RESUMO

A population of more than six million people worldwide at high risk of Alzheimer's disease (AD) are those with Down Syndrome (DS, caused by trisomy 21 (T21)), 70% of whom develop dementia during lifetime, caused by an extra copy of ß-amyloid-(Aß)-precursor-protein gene. We report AD-like pathology in cerebral organoids grown in vitro from non-invasively sampled strands of hair from 71% of DS donors. The pathology consisted of extracellular diffuse and fibrillar Aß deposits, hyperphosphorylated/pathologically conformed Tau, and premature neuronal loss. Presence/absence of AD-like pathology was donor-specific (reproducible between individual organoids/iPSC lines/experiments). Pathology could be triggered in pathology-negative T21 organoids by CRISPR/Cas9-mediated elimination of the third copy of chromosome 21 gene BACE2, but prevented by combined chemical ß and γ-secretase inhibition. We found that T21 organoids secrete increased proportions of Aß-preventing (Aß1-19) and Aß-degradation products (Aß1-20 and Aß1-34). We show these profiles mirror in cerebrospinal fluid of people with DS. We demonstrate that this protective mechanism is mediated by BACE2-trisomy and cross-inhibited by clinically trialled BACE1 inhibitors. Combined, our data prove the physiological role of BACE2 as a dose-sensitive AD-suppressor gene, potentially explaining the dementia delay in ~30% of people with DS. We also show that DS cerebral organoids could be explored as pre-morbid AD-risk population detector and a system for hypothesis-free drug screens as well as identification of natural suppressor genes for neurodegenerative diseases.


Assuntos
Doença de Alzheimer , Síndrome de Down , Doença de Alzheimer/genética , Secretases da Proteína Precursora do Amiloide/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidases/genética , Ácido Aspártico Endopeptidases/metabolismo , Encéfalo/metabolismo , Síndrome de Down/genética , Genes Supressores , Humanos , Organoides/metabolismo , Trissomia
10.
Proc Natl Acad Sci U S A ; 116(36): 17701-17706, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31431528

RESUMO

Complex and correlated quantum systems with promise for new functionality often involve entwined electronic degrees of freedom. In such materials, highly unusual properties emerge and could be the result of electron localization. Here, a cubic heavy fermion metal governed by spins and orbitals is chosen as a model system for this physics. Its properties are found to originate from surprisingly simple low-energy behavior, with 2 distinct localization transitions driven by a single degree of freedom at a time. This result is unexpected, but we are able to understand it by advancing the notion of sequential destruction of an SU(4) spin-orbital-coupled Kondo entanglement. Our results implicate electron localization as a unified framework for strongly correlated materials and suggest ways to exploit multiple degrees of freedom for quantum engineering.

11.
Br J Psychiatry ; 218(6): 302-304, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33648616

RESUMO

We explore whether the needs of individuals with neurodevelopment disorders have been overlooked during the coronavirus disease 2019 (COVID-19) pandemic and set out the issues that need to be considered in response to future health crises and pandemics.


Assuntos
COVID-19 , Influenza Humana , Transtornos do Neurodesenvolvimento , Humanos , Influenza Humana/epidemiologia , Transtornos do Neurodesenvolvimento/epidemiologia , Transtornos do Neurodesenvolvimento/terapia , Pandemias , SARS-CoV-2
12.
Alzheimers Dement ; 17(4): 595-604, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33226718

RESUMO

INTRODUCTION: People with Down syndrome (DS) typically develop Alzheimer's disease (AD) neuropathology before age 40, but a lack of outcome measures and longitudinal data have impeded their inclusion in randomized controlled trials (RCTs). METHODS: Cohort study. Event-based and dose-response Emax models were fitted to longitudinal cognitive data, to stage AD and determine the earliest ages of decline. Results informed sample size estimations for hypothetical RCTs of disease-modifying treatments that reduced decline by 35% or 75%. RESULTS: Seventy-five percent of participants progressed or remained stable in the AD staging model; effect sizes varied by age group and tests. Varied treatment effects could be detected with 50-200 people per arm when using sensitive cognitive outcome measures and targeting recruitment to ages 36 to 45 years. DISCUSSION: Efficient RCTs of AD preventative treatments can be conducted in the DS population using sensitive outcome measures to monitor early decline. Dose-response models could help tailor future RCTs.


Assuntos
Doença de Alzheimer/patologia , Síndrome de Down/patologia , Avaliação de Resultados em Cuidados de Saúde , Sintomas Prodrômicos , Projetos de Pesquisa , Tamanho da Amostra , Adulto , Fatores Etários , Estudos de Coortes , Síndrome de Down/complicações , Inglaterra , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade
13.
Nat Rev Neurosci ; 16(9): 564-74, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26243569

RESUMO

Down syndrome, which arises in individuals carrying an extra copy of chromosome 21, is associated with a greatly increased risk of early-onset Alzheimer disease. It is thought that this risk is conferred by the presence of three copies of the gene encoding amyloid precursor protein (APP)--an Alzheimer disease risk factor--although the possession of extra copies of other chromosome 21 genes may also play a part. Further study of the mechanisms underlying the development of Alzheimer disease in people with Down syndrome could provide insights into the mechanisms that cause dementia in the general population.


Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Síndrome de Down/diagnóstico , Síndrome de Down/genética , Predisposição Genética para Doença/genética , Doença de Alzheimer/etiologia , Peptídeos beta-Amiloides/genética , Humanos
14.
Cereb Cortex ; 29(5): 2279-2290, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30877793

RESUMO

Individuals with Down syndrome (DS) show high inter-subject variability in cognitive ability and have an ultra-high risk of developing dementia (90% lifetime prevalence). Elucidating factors underlying variability in cognitive function can inform us about intellectual disability (ID) and may improve our understanding of factors associated with later cognitive decline. Increased neuronal inhibition has been posited to contribute to ID in DS. Combining electroencephalography (EEG) with dynamic causal modeling (DCM) provides a non-invasive method for investigating excitatory/inhibitory mechanisms. Resting-state EEG recordings were obtained from 36 adults with DS with no evidence of cognitive decline. Theta-alpha activity (4-13 Hz) was characterized in relation to general cognitive ability (raw Kaufmann's Brief Intelligence Test second Edition (KBIT-2) score). Higher KBIT-2 was associated with higher frontal alpha peak amplitude and higher theta-alpha band power across distributed regions. Modeling this association with DCM revealed intrinsic self-inhibition was the key network parameter underlying observed differences in 4-13 Hz power in relation to KBIT-2 and age. In particular, intrinsic self-inhibition in right V1 was negatively correlated with KBIT-2. Results suggest intrinsic self-inhibition within the alpha network is associated with individual differences in cognitive ability in adults with DS, and may provide a potential therapeutic target for cognitive enhancement.


Assuntos
Ritmo alfa , Encéfalo/fisiopatologia , Cognição/fisiologia , Síndrome de Down/fisiopatologia , Síndrome de Down/psicologia , Ritmo Teta , Adolescente , Adulto , Feminino , Humanos , Testes de Inteligência , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Inibição Neural , Processamento de Sinais Assistido por Computador , Adulto Jovem
15.
BMC Psychiatry ; 20(1): 161, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32293383

RESUMO

BACKGROUND: Although Positive Behaviour Support (PBS) is a widely used intervention for ameliorating challenging behaviour (CB), evidence for its use in adults with intellectual disability (ID) and comorbid autism (ASD) is lacking. We report a planned subsidiary analysis of adults with both ASD and ID who participated in a randomised trial of PBS delivered by health professionals. METHODS: The study was a multicentre, cluster randomised trial conducted in 23 community ID services in England, participants were randomly allocated to either the delivery of PBS (n = 11 clusters) or to treatment as usual (TAU; n = 12). One-hundred and thirteen participants (46% of all participants in the trial) had a diagnosis of ID, autism spectrum disorder and CB (ASD+); (47 allocated to the intervention arm, and 66 to the control). CB (primary outcome) was measured with the Aberrant Behaviour Checklist total score (ABC-CT). Secondary outcomes included mental health status, psychotropic medication use, health and social care costs and quality adjusted life years (QALYs) over 12 months. RESULTS: There were no statistically significant differences in ABC-CT between ASD+ groups randomised to the two arms over 12 months (adjusted mean difference = - 2.10, 95% CI: - 11.3 7.13, p = 0.655) or other measures. The mean incremental cost of the intervention per participant was £628 (95% CI -£1004 to £2013). There was a difference of 0.039 (95% CI - 0.028 to 0.103) for QALYs and a cost per QALY gained of £16,080. CONCLUSIONS: Results suggest lack of clinical effectiveness for PBS delivered by specialist ID clinical teams. Further evidence is needed from larger trials, and development of improved interventions. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01680276.


Assuntos
Transtorno do Espectro Autista , Deficiência Intelectual , Adulto , Transtorno do Espectro Autista/terapia , Análise Custo-Benefício , Inglaterra , Humanos , Deficiência Intelectual/terapia , Qualidade de Vida
16.
Alzheimers Dement ; 16(7): 1065-1077, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32544310

RESUMO

Improved medical care of individuals with Down syndrome (DS) has led to an increase in life expectancy to over the age of 60 years. In conjunction, there has been an increase in age-related co-occurring conditions including Alzheimer's disease (AD). Understanding the factors that underlie symptom and age of clinical presentation of dementia in people with DS may provide insights into the mechanisms of sporadic and DS-associated AD (DS-AD). In March 2019, the Alzheimer's Association, Global Down Syndrome Foundation and the LuMind IDSC Foundation partnered to convene a workshop to explore the state of the research on the intersection of AD and DS research; to identify research gaps and unmet needs; and to consider how best to advance the field. This article provides a summary of discussions, including noting areas of emerging science and discovery, considerations for future studies, and identifying open gaps in our understanding for future focus.


Assuntos
Doença de Alzheimer/complicações , Síndrome de Down/complicações , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Síndrome de Down/metabolismo , Humanos
17.
J Nanosci Nanotechnol ; 19(9): 5692-5699, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30961726

RESUMO

We report on the effect of α-Fe2O3 phase in the magnetic properties and magnetic interactions in nickel ferrite (NiFe2O4-NFO) nanoparticles synthesized by co-precipitation method. Structural analysis confirms the formation of the cubic inverse spinel phase without any impurities for the NFO sample annealed in air at 650 °C. When the annealing temperature is increased to 750 °C and 850 °C, α-Fe2O3 impurity phase is formed along with the parent NFO phase. Raman spectra recorded at room temperature (RT) confirm the presence of pure NFO phase for the sample annealed at 650 °C, and presence of α-Fe2O3 phase is observed in the samples annealed at 750 °C and 850 °C. Saturation magnetization values at RT for the NFO samples annealed at 650 °C, 750 °C and 850 °C are 34 emu/g, 19 emu/g and 28 emu/g respectively. Zero Field Cooled (ZFC) and Field Cooled (FC) measurement reveals the super-paramagnetic behavior along with competing magnetic interactions in all the samples. For the NFO sample annealed at 750 °C and 850 °C, a drop in ZFC magnetization and a small kink in FC magnetization observed around 245 K indicate the presence of a Morin transition (TM) from the α-Fe2O3 phase. Anisotropy constants were calculated for all the samples using the law of approach to saturation (LAS) method. The magnetocrystalline anisotropy energy distribution function for the NFO samples annealed at 750 °C and 850 °C exhibit broad peak due to the random distribution of spins associated with different particle size.

18.
Alzheimers Dement ; 15(2): 245-257, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30503169

RESUMO

INTRODUCTION: Down syndrome (DS) is associated with an almost universal development of Alzheimer's disease. Individuals with DS are therefore an important population for randomized controlled trials to prevent or delay cognitive decline, though it is essential to understand the time course of early cognitive changes. METHODS: We conducted the largest cognitive study to date with 312 adults with DS to assess age-related and Alzheimer's disease-related cognitive changes during progression from preclinical to prodromal dementia, and prodromal to clinical dementia. RESULTS: Changes in memory and attention measures were most sensitive to early decline. Resulting sample size calculations for randomized controlled trials to detect significant treatment effects to delay decline were modest. DISCUSSION: Our findings address uncertainties around the development of randomized controlled trials to delay cognitive decline in DS. Such trials are essential to reduce the high burden of dementia in people with DS and could serve as proof-of-principle trials for some drug targets.


Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/fisiopatologia , Biomarcadores , Disfunção Cognitiva/diagnóstico , Síndrome de Down/fisiopatologia , Sintomas Prodrômicos , Adolescente , Adulto , Progressão da Doença , Síndrome de Down/genética , Feminino , Humanos , Pessoa de Meia-Idade , Testes Neuropsicológicos/estatística & dados numéricos , Adulto Jovem
19.
Alzheimers Dement ; 15(2): 292-312, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30555031

RESUMO

Alzheimer's disease and related dementias (ADRDs) are a global crisis facing the aging population and society as a whole. With the numbers of people with ADRDs predicted to rise dramatically across the world, the scientific community can no longer neglect the need for research focusing on ADRDs among underrepresented ethnoracial diverse groups. The Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART; alz.org/ISTAART) comprises a number of professional interest areas (PIAs), each focusing on a major scientific area associated with ADRDs. We leverage the expertise of the existing international cadre of ISTAART scientists and experts to synthesize a cross-PIA white paper that provides both a concise "state-of-the-science" report of ethnoracial factors across PIA foci and updated recommendations to address immediate needs to advance ADRD science across ethnoracial populations.


Assuntos
Doença de Alzheimer/etnologia , Doença de Alzheimer/epidemiologia , Etnicidade , Disparidades em Assistência à Saúde , Grupos Raciais , Idoso , Biomarcadores , Pesquisa Biomédica , Humanos
20.
Acta Neuropathol ; 136(4): 569-587, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29770843

RESUMO

In this study, we have compared the severity of amyloid plaque formation and cerebral amyloid angiopathy (CAA), and the subtype pattern of CAA pathology itself, between APP genetic causes of AD (APPdup, APP mutations), older individuals with Down syndrome (DS) showing the pathology of Alzheimer's disease (AD) and individuals with sporadic (early and late onset) AD (sEOAD and sLOAD, respectively). The aim of this was to elucidate important group differences and to provide mechanistic insights related to clinical and neuropathological phenotypes. Since lipid and cholesterol metabolism is implicated in AD as well as vascular disease, we additionally aimed to explore the role of APOE genotype in CAA severity and subtypes. Plaque formation was greater in DS and missense APP mutations than in APPdup, sEOAD and sLOAD cases. Conversely, CAA was more severe in APPdup and missense APP mutations, and in DS, compared to sEOAD and sLOAD. When stratified by CAA subtype from 1 to 4, there were no differences in plaque scores between the groups, though in patients with APPdup, APP mutations and sEOAD, types 2 and 3 CAA were more common than type 1. Conversely, in DS, sLOAD and controls, type 1 CAA was more common than types 2 and 3. APOE ε4 allele frequency was greater in sEOAD and sLOAD compared to APPdup, missense APP mutations, DS and controls, and varied between each of the CAA phenotypes with APOE ε4 homozygosity being more commonly associated with type 3 CAA than types 1 and 2 CAA in sLOAD and sEOAD. The differing patterns in CAA within individuals of each group could be a reflection of variations in the efficiency of perivascular drainage, this being less effective in types 2 and 3 CAA leading to a greater burden of CAA in parenchymal arteries and capillaries. Alternatively, as suggested by immunostaining using carboxy-terminal specific antibodies, it may relate to the relative tissue burdens of the two major forms of Aß, with higher levels of Aß40 promoting a more 'aggressive' form of CAA, and higher levels of Aß42(3) favouring a greater plaque burden. Possession of APOE ε4 allele, especially ε4 homozygosity, favours development of CAA generally, and as type 3 particularly, in sEOAD and sLOAD.


Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Amiloide/metabolismo , Vasos Sanguíneos/metabolismo , Síndrome de Down/genética , Síndrome de Down/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Apolipoproteínas E/genética , Angiopatia Amiloide Cerebral/genética , Angiopatia Amiloide Cerebral/patologia , Feminino , Duplicação Gênica , Frequência do Gene , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Placa Amiloide/genética , Placa Amiloide/patologia
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