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- Bateman, Daniel R., et al.
(författare)
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Agitation and impulsivity in mid and late life as possible riskmarkers for incident dementia
- 2020
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Ingår i: Alzheimer’s & Dementia. - : Elsevier. - 2352-8737. ; 6:1
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Forskningsöversikt (refereegranskat)abstract
- To identify knowledge gaps regarding new-onset agitation and impulsivity prior to onsetof cognitive impairment or dementia the International Society to Advance Alzheimer’sResearch and Treatment Neuropsychiatric Syndromes (NPS) Professional InterestAreaconducted a scoping review. Extending a series of reviews exploring the pre-dementiarisk syndrome Mild Behavioral Impairment (MBI), we focused on late-onset agitationand impulsivity (the MBI impulse dyscontrol domain) and risk of incident cognitivedecline and dementia. This scoping review of agitation and impulsivity pre-dementiasyndromes summarizes the current biomedical literature in terms of epidemiology,diagnosis andmeasurement, neurobiology, neuroimaging, biomarkers, course and prognosis,treatment, and ongoing clinical trials. Validations for pre-dementia scales suchas the MBI Checklist, and incorporation into longitudinal and intervention trials, areneeded to better understand impulse dyscontrol as a risk factor for mild cognitiveimpairment and dementia.
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2. |
- Benussi, A., et al.
(författare)
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Differences and similarities between familial and sporadic frontotemporal dementia: An Italian single-center cohort study
- 2022
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Ingår i: Alzheimer's and Dementia: Translational Research and Clinical Interventions. - : Wiley. - 2352-8737. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction The possibility to generalize our understandings on treatments and assessments to both familial frontotemporal dementia (f-FTD) and sporadic FTD (s-FTD) is a fundamental perspective for the near future, considering the constant advancement in potential disease-modifying therapies that target particular genetic forms of FTD. We aimed to investigate differences in clinical features, cerebrospinal fluid (CSF), and blood-based biomarkers between f-FTD and s-FTD. Methods In this longitudinal cohort study, we evaluated a consecutive sample of symptomatic FTD patients, classified as f-FTD and s-FTD according to Goldman scores (GS). All patients underwent clinical, behavioral, and neuropsychiatric symptom assessment, CSF biomarkers and serum neurofilament light (NfL) analysis, and brain atrophy evaluation with magnetic resonance imaging. Results Of 570 patients with FTD, 123 were classified as f-FTD, and 447 as s-FTD. In the f-FTD group, 95 had a pathogenic FTD mutation while 28 were classified as GS = 1 or 2; of the s-FTD group, 133 were classified as GS = 3 and 314 with GS = 4. f-FTD and s-FTD cases showed comparable demographic features, except for younger age at disease onset, age at diagnosis, and higher years of education in the f-FTD group (all P < .05). f-FTD showed worse behavioral disturbances as measured with Frontal Behavioral Inventory (FBI) negative behaviors (14.0 +/- 7.6 vs. 11.6 +/- 7.4, P = .002), and positive behaviors (20.0 +/- 11.0 vs. 17.4 +/- 11.8, P = .031). Serum NfL concentrations were higher in patients with f-FTD (70.9 +/- 37.9 pg/mL) compared to s-FTD patients (37.3 +/- 24.2 pg/mL, P < .001), and f-FTD showed greater brain atrophy in the frontal and temporal regions and basal ganglia. Patients with f-FTD had significantly shorter survival than those with s-FTD (P = .004). Discussion f-FTD and s-FTD are very similar clinical entities, but with different biological mechanisms, and different rates of progression. The parallel characterization of both f-FTD and s-FTD will improve our understanding of the disease, and aid in designing future clinical trials for both genetic and sporadic forms of FTD. Highlights Do clinical features and biomarkers differ between patients with familial frontotemporal dementia (f-FTD) and sporadic FTD (s-FTD)? In this cohort study of 570 patients with FTD, f-FTD and s-FTD share similar demographic features, but with younger age at disease onset and diagnosis in the f-FTD group. f-FTD showed higher serum neurofilament light concentrations, greater brain damage, and shorter survival, compared to s-FTD. f-FTD and s-FTD are very similar clinical entities, but with different cognitive reserve mechanisms and different rates of progression.
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- Brum, Wagner S., et al.
(författare)
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A three-range approach enhances the prognostic utility of CSF biomarkers in Alzheimer's disease.
- 2022
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Ingår i: Alzheimer's & dementia (New York, N. Y.). - : Wiley. - 2352-8737. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease consensus recommends biomarker dichotomization, a practice with well-described clinical strengths and methodological limitations. Although neuroimaging studies have explored alternative biomarker interpretation strategies, a formally defined three-range approach and its prognostic impact remains under-explored for cerebrospinal fluid (CSF) biomarkers .With two-graph receiver-operating characteristics based on different reference schemes, we derived three-range cut-points for CSF Elecsys biomarkers. According to baseline CSF status, we assessed the prognostic utility of this in predicting risk of clinical progression and longitudinal trajectories of cognitive decline and amyloid-beta (Aβ) positron emission tomography (PET) accumulation in non-demented individuals (Alzheimer's Disease Neuroimaging Initiative [ADNI]; n=1246). In all analyses, we compared herein-derived three-range CSF cut-points to previously described binary ones.In our main longitudinal analyses, we highlight CSF p-tau181/Aβ1-42 three-range cut-points derived based on the cognitively normal Aβ-PET negative versus dementia Aβ-PET positive reference scheme for best depicting a prognostically relevant biomarker abnormality range. Longitudinally, our approach revealed a divergent intermediate cognitive trajectory undetected by dichotomization and a clearly abnormal group at higher risk for cognitive decline, with power analyses suggesting the latter group as potential trial enrichment candidates. Furthermore, we demonstrate that individuals with intermediate-range CSF status have similar rates of Aβ deposition to those in the clearly abnormal group.The proposed approach can refine clinico-biological prognostic assessment and potentially enhance trial recruitment, as it captures faster biomarker-related cognitive decline in comparison to binary cut-points. Although this approach has implications for trial recruitment and observational studies, further discussion is needed regarding clinical practice applications.
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5. |
- Choi, Seo Eun, et al.
(författare)
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Development and validation of language and visuospatial composite scores in ADNI
- 2020
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Ingår i: Alzheimer's and Dementia: Translational Research and Clinical Interventions. - : Wiley. - 2352-8737. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Composite scores may be useful to summarize overall language or visuospatial functioning in studies of older adults. Methods:We used item response theory to derive composite measures for language (ADNI-Lan) and visuospatial functioning (ADNI-VS) from the cognitive battery administered in the Alzheimer’s Disease Neuroimaging Initiative (ADNI). We evaluated the scores among groups of people with normal cognition, mild cognitive impairment (MCI), and Alzheimer’s disease (AD) in terms of responsiveness to change, association with imaging findings, and ability to differentiate between MCI participants who progressed to AD dementia and those who did not progress. Results: ADNI-Lan andADNI-VSwere able to detect change over time and predict conversion fromMCI toAD. Theywere associated with most of the pre-specified magnetic resonance imaging measures. ADNI-Lan had strong associations with a cerebrospinal fluid biomarker pattern. Discussion: ADNI-Lan and ADNI-VS may be useful composites for language and visuospatial functioning in ADNI.
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7. |
- de Erausquin, Gabriel A, et al.
(författare)
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Chronic neuropsychiatric sequelae of SARS-CoV-2: Protocol and methods from the Alzheimer's Association Global Consortium.
- 2022
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Ingår i: Alzheimer's & dementia (New York, N. Y.). - : Wiley. - 2352-8737. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Coronavirus disease 2019 (COVID-19) has caused >3.5 million deaths worldwide and affected >160 million people. At least twice as many have been infected but remained asymptomatic or minimally symptomatic. COVID-19 includes central nervous system manifestations mediated by inflammation and cerebrovascular, anoxic, and/or viral neurotoxicity mechanisms. More than one third of patients with COVID-19 develop neurologic problems during the acute phase of the illness, including loss of sense of smell or taste, seizures, and stroke. Damage or functional changes to the brain may result in chronic sequelae. The risk of incident cognitive and neuropsychiatric complications appears independent from the severity of the original pulmonary illness. It behooves the scientific and medical community to attempt to understand the molecular and/or systemic factors linking COVID-19 to neurologic illness, both short and long term.This article describes what is known so far in terms of links among COVID-19, the brain, neurological symptoms, and Alzheimer's disease (AD) and related dementias. We focus on risk factors and possible molecular, inflammatory, and viral mechanisms underlying neurological injury. We also provide a comprehensive description of the Alzheimer's Association Consortium on Chronic Neuropsychiatric Sequelae of SARS-CoV-2 infection (CNS SC2) harmonized methodology to address these questions using a worldwide network of researchers and institutions.Successful harmonization of designs and methods was achieved through a consensus process initially fragmented by specific interest groups (epidemiology, clinical assessments, cognitive evaluation, biomarkers, and neuroimaging). Conclusions from subcommittees were presented to the whole group and discussed extensively. Presently data collection is ongoing at 19 sites in 12 countries representing Asia, Africa, the Americas, and Europe.The Alzheimer's Association Global Consortium harmonized methodology is proposed as a model to study long-term neurocognitive sequelae of SARS-CoV-2 infection.The following review describes what is known so far in terms of molecular and epidemiological links among COVID-19, the brain, neurological symptoms, and AD and related dementias (ADRD)The primary objective of this large-scale collaboration is to clarify the pathogenesis of ADRD and to advance our understanding of the impact of a neurotropic virus on the long-term risk of cognitive decline and other CNS sequelae. No available evidence supports the notion that cognitive impairment after SARS-CoV-2 infection is a form of dementia (ADRD or otherwise). The longitudinal methodologies espoused by the consortium are intended to provide data to answer this question as clearly as possible controlling for possible confounders. Our specific hypothesis is that SARS-CoV-2 triggers ADRD-like pathology following the extended olfactory cortical network (EOCN) in older individuals with specific genetic susceptibility.The proposed harmonization strategies and flexible study designs offer the possibility to include large samples of under-represented racial and ethnic groups, creating a rich set of harmonized cohorts for future studies of the pathophysiology, determinants, long-term consequences, and trends in cognitive aging, ADRD, and vascular disease.We provide a framework for current and future studies to be carried out within the Consortium. and offers a "green paper" to the research community with a very broad, global base of support, on tools suitable for low- and middle-income countries aimed to compare and combine future longitudinal data on the topic.The Consortium proposes a combination of design and statistical methods as a means of approaching causal inference of the COVID-19 neuropsychiatric sequelae. We expect that deep phenotyping of neuropsychiatric sequelae may provide a series of candidate syndromes with phenomenological and biological characterization that can be further explored. By generating high-quality harmonized data across sites we aim to capture both descriptive and, where possible, causal associations.
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8. |
- Donohue, Michael C., et al.
(författare)
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Cross-validation of optimized composites for preclinical Alzheimer's disease
- 2017
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Ingår i: Alzheimer's and Dementia: Translational Research and Clinical Interventions. - : Wiley. - 2352-8737. ; 3:1, s. 123-129
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Tidskriftsartikel (refereegranskat)abstract
- Introduction We discuss optimization and validation of composite end points for presymptomatic Alzheimer's disease clinical trials. Optimized composites offer hope of substantial gains in statistical power or reduction in sample size. But there is tradeoff between optimization and face validity such that optimization should only be considered if there is a convincing rationale. As with statistically derived regions of interest in neuroimaging, validation on independent data sets is essential. Methods Using four data sets, we consider the optimized weighting of four components of a cognitive composite which includes measures of (1) global cognition, (2) semantic memory, (3) episodic memory, and (4) executive function. Weights are optimized to either discriminate amyloid positivity or maximize power to detect a treatment effect in an amyloid-positive population. We apply repeated 5 × 3-fold cross-validation to quantify the out-of-sample performance of optimized composite end points. Results We found the optimized weights varied greatly across the folds of the cross-validation with either optimization method. Both optimization methods tend to down-weight the measures of global cognition and executive function. However, when these optimized composites were applied to the validation sets, they did not provide consistent improvements in power. In fact, overall, the optimized composites performed worse than those without optimization. Discussion We find that component weight optimization does not yield valid improvements in sensitivity of this composite to detect treatment effects.
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- Feng, Nicole C., et al.
(författare)
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Feasibility of an at-home, web-based, interactive exercise program for older adults
- 2019
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Ingår i: Alzheimer’s & Dementia. - : John Wiley & Sons. - 2352-8737. ; 5:1, s. 825-833
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Increased physical exercise is linked to enhanced brain health and reduced dementia risk. Exercise intervention studies usually are conducted at facilities in groups under trainer supervision. To improve scalability, accessibility, and engagement, programs may need to be structured such that individuals can execute and adjust routines in their own homes.Methods: One hundred eighty-three healthy older adults from two sites (the United States and Sweden) were screened. One hundred fifty-six subjects (mean age 73.2), randomly assigned to one of four interventions (PACE-Yourself physical exercise program, mindfulness meditation, or Cogmed® adaptive or nonadaptive computerized working memory training) began the study. All interventions were structurally similar: occurring in subjects' homes using interactive, web-based software, over five weeks, ∼175 minutes/week. In the PACE-Yourself program, video segments presented aerobic exercises at different pace and intensity (P&I). The program paused frequently, allowing subjects to indicate whether P&I was "too easy," "too hard," or "somewhat hard." P&I of the subsequent exercise set was adjusted, allowing subjects to exercise at a perceived exertion level of "somewhat hard." Program completion was defined as finishing ≥60% of sessions.Results: A high percentage of participants in all groups completed the program, although the number (86%) was slightly lower in the PACE-Yourself group than the other three. Excluding dropouts, the PACE-Yourself group had a lower adherence rate of 93%, compared with the other three (∼98%). Over the five weeks, PACE-Yourself participants increased exercising at the highest intensity level, consistent with augmented aerobic activity over time. The number of exercise sessions completed predicted the postintervention versus preintervention increase in self-reported level of physical activity.Discussion: This study supports the feasibility of a home-based, subject-controlled, exercise program in which P&I is regulated via real-time participant feedback, which may promote self-efficacy. Further study is needed to determine if similar results are found over longer periods and in more diverse populations.
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- Hemmingsson, Eva-Stina, et al.
(författare)
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Antiviral treatment associated with reduced risk of clinical Alzheimer's disease : A nested case-control study
- 2021
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Ingår i: Alzheimer’s & Dementia. - : John Wiley & Sons. - 2352-8737. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In this nested case-control study, we investigated if antiviral treatment given prior to onset of Alzheimer's disease (AD) could influence incident AD.Methods: From a large population-based cohort study in northern Sweden, 262 individuals that later developed AD were compared to a non-AD matched control group with respect to prescriptions of herpes antiviral treatment. All included subjects were herpes simplex virus 1 (HSV1) carriers and the matching criteria were age, sex, apolipoprotein E genotype (ε4 allele carriership), and study sample start year.Results: Among those who developed AD, 6 prescriptions of antivirals were found, compared to 20 among matched controls. Adjusted for length of follow-up, a conditional logistic regression indicated a difference in the risk for AD development between groups (odds ratio for AD with an antiviral prescription 0.287, P = .018).Discussion: Antiviral treatment might possibly reduce the risk for later development of HSV1-associated AD.
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13. |
- Jensen, C. S., et al.
(författare)
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Effect of physical exercise on markers of neuronal dysfunction in cerebrospinal fluid in patients with Alzheimer's disease
- 2017
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Ingår i: Alzheimer's and Dementia: Translational Research and Clinical Interventions. - : Wiley. - 2352-8737. ; 3:2, s. 284-290
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Physical exercise has gained increasing focus as a potential mean to maintain cognitive function in patients with Alzheimer's disease (AD). Alongside the markers of specific AD pathology (amyloid β and tau), other pathologies such as neuronal damage and synaptic loss have been proposed as markers of the disease. Here, we study the effect of physical exercise on biomarkers of neuronal and synaptic integrity. Methods Cerebrospinal fluid (CSF) from 51 AD subjects who participated in the randomized controlled trial Preserving Cognition, Quality of Life, Physical Health and Functional Ability in Alzheimer's Disease: The Effect of Physical Exercise (ADEX) was analyzed for the concentration of neurofilament light (NFL), neurogranin (Ng), visinin-like protein-1 (VILIP-1), and chitinase-3–like protein 1 (YKL-40). Participants were subjected to either 16weeks of moderate- to high-intensity exercise (n=25) or treatment as usual (control group, n=26), and CSF was collected before and after intervention. Results No significant differences in CSF concentrations of VILIP-1, YKL-40, NFL, and Ng were observed when comparing mean change from baseline between the exercise and control groups. Similarly, when classifying subjects based on their exercise levels, no significant changes were observed for the biomarkers in the control group compared with the high-exercise group (attending 80% of the exercise sessions with an intensity of 70% of maximum heart rate or above). Discussion These results are not supportive of a modulatory effect of physical exercise on the selected biomarkers of neuronal and synaptic integrity in patients with AD. © 2017 The Authors
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- Karlsson, Ida K., et al.
(författare)
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Change in cognition and body mass index in relation to preclinical dementia
- 2021
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Ingår i: Alzheimer’s & Dementia. - : John Wiley & Sons. - 2352-8737. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: To study if declining cognition drives weight loss in preclinical dementia, we examined the longitudinal association between body mass index (BMI) and cognitive abilities in individuals who did or did not later develop dementia.Methods: Using data from individuals spanning age 50 to 89, we applied dual change score models separately in individuals who remained cognitively intact (n = 1498) and those who were diagnosed with dementia within 5 years of last assessment (n = 459).Results: Among the cognitively intact, there was a bidirectional association: Stable BMI predicted stable cognition and vice versa. Among individuals who were subsequently diagnosed with dementia, the association was unidirectional: Higher BMI predicted declining cognition but cognition did not predict change in BMI.Discussion: Although BMI and cognition stabilized each other when cognitive functioning was intact, this buffering effect was missing in the preclinical dementia phase. This finding indicates that weight loss in preclinical dementia is not driven by declining cognition.
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- Landen, Jaren W., et al.
(författare)
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Ponezumab in mild-to-moderate Alzheimer's disease : Randomized phase II PET-PIB study
- 2017
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Ingår i: Alzheimer's and Dementia: Translational Research and Clinical Interventions. - : Wiley. - 2352-8737. ; 3:3, s. 393-401
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Tidskriftsartikel (refereegranskat)abstract
- Introduction The safety, pharmacokinetics, and effect on peripheral and central amyloid β (Aβ) of multiple doses of ponezumab, an anti-Aβ monoclonal antibody, were characterized in subjects with mild-to-moderate Alzheimer's disease treated for 1 year. Methods Subjects were aged ≥50 years with Mini–Mental State Examination scores 16 to 26. Cohort Q was randomized to ponezumab 10 mg/kg (n = 12) or placebo (n = 6) quarterly. Cohort M was randomized to a loading dose of ponezumab 10 mg/kg or placebo, followed by monthly ponezumab 7.5 mg/kg (n = 12) or placebo (n = 6), respectively. Results Ponezumab was generally well tolerated. Plasma concentrations increased dose dependently, but cerebrospinal fluid (CSF) penetration was low. Plasma Aβ increased dose dependently with ponezumab, but CSF biomarkers, brain amyloid burden, cognition, and function were not affected. Conclusions Both ponezumab dosing schedules were generally safe and well tolerated but did not alter CSF biomarkers, brain amyloid burden, or clinical outcomes.
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- Lindman, Karin Lopatko, et al.
(författare)
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A genetic signature including apolipoprotein E epsilon 4 potentiates the risk of herpes simplex-associated Alzheimer's disease
- 2019
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Ingår i: Alzheimer’s & Dementia. - : Wiley. - 2352-8737. ; 5:1, s. 697-704
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionHerpes simplex virus type 1 (HSV1) in combination with genetic susceptibility has previously been implicated in Alzheimer's disease (AD) pathogenesis. MethodsPlasma from 360 AD cases, obtained on average 9.6years before diagnosis, and their age- and sex-matched controls, were analyzed for anti-HSV1 immunoglobulin (Ig) G with enzyme-linked immunosorbent assays (ELISAs). APOE genotype and nine other selected risk genes for AD were extracted from a genome-wide association study analysis by deCODE genetics, Reykjavik, Iceland. ResultsThe interaction between APOE epsilon 4 heterozygosity (APOE epsilon 2/epsilon 4 or epsilon 3/epsilon 4) and anti-HSV1 IgG carriage increased the risk of AD (OR 4.55, P=.02). A genetic risk score based on the nine AD risk genes also interacted with anti-HSV1 IgG for the risk of developing AD (OR 2.35, P=.01). DiscussionThe present findings suggest that the APOE epsilon 4 allele and other AD genetic risk factors might potentiate the risk of HSV1-associated AD.
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20. |
- Lopatko Lindman, Karin, et al.
(författare)
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A genetic signature including apolipoprotein Eε4 potentiates the risk of herpes simplex-associated Alzheimer's disease
- 2019
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Ingår i: Alzheimer’s & Dementia. - : Wiley. - 2352-8737. ; 5, s. 697-704
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Herpes simplex virus type 1 (HSV1) in combination with genetic susceptibility has previously been implicated in Alzheimer's disease (AD) pathogenesis.Methods: Plasma from 360 AD cases, obtained on average 9.6 years before diagnosis, and their age- and sex-matched controls, were analyzed for anti-HSV1 immunoglobulin (Ig) G with enzyme-linked immunosorbent assays (ELISAs). APOE genotype and nine other selected risk genes for AD were extracted from a genome-wide association study analysis by deCODE genetics, Reykjavik, Iceland.Results: The interaction between APOEε4 heterozygosity (APOEε2/ε4 or ε3/ε4) and anti-HSV1 IgG carriage increased the risk of AD (OR 4.55, P = .02). A genetic risk score based on the nine AD risk genes also interacted with anti-HSV1 IgG for the risk of developing AD (OR 2.35, P = .01).Discussion: The present findings suggest that the APOEε4 allele and other AD genetic risk factors might potentiate the risk of HSV1-associated AD.
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21. |
- Lopatko Lindman, Karin, et al.
(författare)
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Herpesvirus infections, antiviral treatment, and the risk ofdementia : a registry-based cohort study in Sweden
- 2021
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Ingår i: Alzheimer’s & Dementia. - : John Wiley & Sons. - 2352-8737. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Herpesviruses, including Herpes simplex virus type 1 (HSV1) and varicella zoster‐virus (VZV), have been implicated in Alzheimer's disease (AD) development. Likewise, antiviral treatment has been suggested to protect against dementia development in herpes‐infected individuals.Methods: The study enrolled 265,172 subjects aged ≥ 50 years, with diagnoses of VZV or HSV, or prescribed antiviral drugs between 31 December 2005 and 31 December 2017. Controls were matched in a 1:1 ratio by sex and birth year.Results: Antiviral treatment was associated with decreased risk of dementia (adjusted hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.86 to 0.92), while herpes infection without antiviral drugs increased the risk of dementia (adjusted HR 1.50, 95% CI 1.29 to 1.74).Discussion: Antiviral treatment was associated with a reduced long‐term risk of dementia among individuals with overt signs of herpes infection. This is consistent with earlier findings indicating that herpesviruses are involved in the pathogenesis of AD.
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22. |
- Ly, Han, et al.
(författare)
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The association of circulating amylin with β-amyloid in familial Alzheimer's disease.
- 2021
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Ingår i: Alzheimer's & dementia. - : Wiley. - 2352-8737. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- This study assessed the hypothesis that circulating human amylin (amyloid-forming) cross-seeds with amyloid beta (Aβ) in early Alzheimer's disease (AD).Evidence of amylin-AD pathology interaction was tested in brains of 31 familial AD mutation carriers and 20 cognitively unaffected individuals, in cerebrospinal fluid (CSF) (98 diseased and 117 control samples) and in genetic databases. For functional testing, we genetically manipulated amylin secretion in APP/PS1 and non-APP/PS1 rats.Amylin-Aβ cross-seeding was identified in AD brains. High CSF amylin levels were associated with decreased CSF Aβ42 concentrations. AD risk and amylin gene are not correlated. Suppressed amylin secretion protected APP/PS1 rats against AD-associated effects. In contrast, hypersecretion or intravenous injection of human amylin in APP/PS1 rats exacerbated AD-like pathology through disruption of CSF-brain Aβ exchange and amylin-Aβ cross-seeding.These findings strengthened the hypothesis of circulating amylin-AD interaction and suggest that modulation of blood amylin levels may alter Aβ-related pathology/symptoms.
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- Melin, Jeanette, et al.
(författare)
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NeuroMET Memory Metric : Improving accuracy and comparability with crosswalks
- 2023
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Ingår i: Alzheimer’s & Dementia. - 2352-8737. ; 19:S4
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Tidskriftsartikel (refereegranskat)abstract
- Background: The ability to measure, track over time, and compare memory ability for people with neurodegeneration is important. However, currently, full comparability of memory test data is limited by a lack of quality assurance of memory measurements. At AAIC 2021, we presented a preliminary item bank to assess memory, composed by selecting items from legacy tests according to metrological principles through use of the Rasch model and with item equivalence based on entropy. Method: Here, we demonstrate direct comparability of measurements generated from different tests, with the new NeuroMET Memory Metric comprising 87 selected items for task difficulty from: the Corsi Block Test, Digit Span Test, Rey’s Auditory Verbal Learning Test, Word Learning List from the CERAD test battery and the Mini Mental State Examination. Data were collected from the European EMPIR NeuroMET and the SmartAge studies recruited at Charité Hospital (Healthy controls n = 92; Subjective cognitive decline n = 160; Mild Cognitive Impairment n = 50; and Alzheimer’s Disease n = 58; age range 55-87). Results: The Rasch analysis showed well-targeted items for all participants’ abilities; good fit to the measurement model, with 83 items (95%) having fit residuals within the expected range and satisfactory unidimensionality, and item reliability of 0.96. The full item bank comprising 87 short-term memory items gave a person reliability of 0.85. Subsequently, a conversion table was created linking the raw scores from the legacy tests to the common NeuroMET Memory Metric and to individual legacy tests. Conclusion: Legacy memory tests have previously proven useful in clinical practice and research, and will continue to be used, but have to date been metrologically limited. The provided conversion table, linking these legacy memory tests to a metrologically assured scale, viz., the NeuroMET memory metric, remedies this deficiency. The NeuroMET memory metric will be included in the first ever prototype of a metrological validated app used to deliver memory tests. Clinicians and researchers will be able to select sets of items to produce data, via a scoring algorithm for transforming patient responses to measures, in a common frame of reference.
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