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Tumor necrosis factor-α (TNF-α) is a pleiotropic, proinflammatory cytokine related to different neurodegenerative diseases, including Alzheimer's disease (AD). Although the linkage between increased TNF-α levels and AD is widely recognized, TNF-α-neutralizing therapies have failed to treat AD. Previous research has associated this with the antithetic functions of the two TNF receptors, TNF receptor 1, associated with inflammation and apoptosis, and TNF receptor 2 (TNFR2), associated with neuroprotection. In our study, we investigated the effects of specifically stimulating TNFR2 with a TNFR2 agonist (NewStar2) in a transgenic Aß-overexpressing mouse model of AD by administering NewStar2 in two different ways: centrally, via implantation of osmotic pumps, or systemically by intraperitoneal injections. We found that both centrally and systemically administered NewStar2 resulted in a drastic reduction in amyloid ß deposition and ß-secretase 1 expression levels. Moreover, activation of TNFR2 increased microglial and astrocytic activation and promoted the uptake and degradation of Aß. Finally, cognitive functions were also improved after NewStar2 treatment. Our results demonstrate that activation of TNFR2 mitigates Aß-induced cognitive deficits and neuropathology in an AD mouse model and indicates that TNFR2 stimulation might be a potential treatment for AD.
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Enfermedad de Alzheimer , Cognición , Receptores Tipo II del Factor de Necrosis Tumoral , Animales , Ratones , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/genética , Péptidos beta-Amiloides/metabolismo , Cognición/efectos de los fármacos , Modelos Animales de Enfermedad , Ratones Transgénicos , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Receptores Tipo II del Factor de Necrosis Tumoral/agonistas , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The development of Alzheimer's disease (AD) involves central and peripheral immune deregulation. Gene identification and studies of AD genetic variants of peripheral immune components may aid understanding of peripheral-central immune crosstalk and facilitate new opportunities for therapeutic intervention. In this study, we have identified in a Flanders-Belgian family a novel variant p.E317D in the Toll-like receptor 9 gene (TLR9), co-segregating with EOAD in an autosomal dominant manner. In human, TLR9 is an essential innate and adaptive immune component predominantly expressed in peripheral immune cells. The p.E317D variant caused 50% reduction in TLR9 activation in the NF-κB luciferase assay suggesting that p.E317D is a loss-of-function mutation. Cytokine profiling of human PBMCs upon TLR9 activation revealed a predominantly anti-inflammatory response in contrast to the inflammatory responses from TLR7/8 activation. The cytokines released upon TLR9 activation suppressed inflammation and promoted phagocytosis of Aß42 oligomers in human iPSC-derived microglia. Transcriptome analysis identified upregulation of AXL, RUBICON and associated signaling pathways, which may underline the effects of TLR9 signaling-induced cytokines in regulating the inflammatory status and phagocytic property of microglia. Our data suggest a protective role of TLR9 signaling in AD pathogenesis, and we propose that TLR9 loss-of-function may disrupt a peripheral-central immune crosstalk that promotes dampening of inflammation and clearance of toxic protein species, leading to the build-up of neuroinflammation and pathogenic protein aggregates in AD development.
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BACKGROUND: A lack of consensus exists in linking demographic, behavioral, and cognitive characteristics to biological stages of dementia, defined by the ATN (amyloid, tau, neurodegeneration) classification incorporating amyloid, tau, and neuronal injury biomarkers. METHODS: Using a random forest classifier we investigated whether 27 demographic, behavioral, and cognitive characteristics allowed distinction between ATN-defined groups with the same cognitive profile. This was done separately for three cognitively unimpaired (CU) (112 A-T-N-; 46 A+T+N+/-; 65 A-T+/-N+/-) and three mild cognitive impairment (MCI) (128 A-T-N-; 223 A+T+N+/-; 94 A-T+/-N+/-) subgroups. RESULTS: Classification-balanced accuracy reached 39% for the CU and 52% for the MCI subgroups. Logical Delayed Recall (explaining 16% of the variance), followed by the Alzheimer's Disease Assessment Scale 13 (14%) and Everyday Cognition Informant (10%), were the most relevant characteristics for classification of the MCI subgroups. Race and ethnicity, marital status, and Everyday Cognition Patient were not relevant (0%). CONCLUSIONS: The demographic, behavioral, and cognitive measures used in our model were not informative in differentiating ATN-defined CU profiles. Measures of delayed memory, general cognition, and activities of daily living were the most informative in differentiating ATN-defined MCI profiles; however, these measures alone were not sufficient to reach high classification performance.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Enfermedad de Alzheimer/psicología , Proteínas tau , Actividades Cotidianas , Disfunción Cognitiva/diagnóstico , Disfunción Cognitiva/psicología , Biomarcadores , Péptidos beta-AmiloidesRESUMEN
The missense mutation p.R406W in microtubule-associated protein tau leads to frontotemporal lobar degeneration with an amnestic, Alzheimer's disease-like phenotype with an autosomal dominant pattern of inheritance. In 2003, we described the pedigree of a Belgian family, labelled ADG, with 28 p.R406W patients. Over 18 years follow-up, we extended the family with 10 p.R406W carriers and provided an in-depth clinical description of the patients. Additionally, genetic screening was used to identify p.R406W carriers in Belgian cohorts of frontotemporal dementia and Alzheimer's disease patients and to calculate p.R406W frequency. In the frontotemporal dementia cohort, we found four p.R406W carriers (n = 647, 0.62%) and three in the Alzheimer's disease cohort (n = 1134, 0.26%). Haplotype sharing analysis showed evidence of a shared haplotype suggesting that they are descendants of a common ancestor. Of the p.R406W patients, we describe characteristics of neuropsychological, imaging and fluid biomarkers as well as neuropathologic examination. Intriguingly, the phenotypic spectrum among the p.R406W patients ranged from typical behavioural variant frontotemporal dementia to clinical Alzheimer's disease, based on CSF biomarker analysis and amyloid PET scan. Heterogeneous overlap syndromes existed in between, with highly common neuropsychiatric symptoms like disinhibition and aggressiveness, which occurred in 100% of frontotemporal dementia and 58% of clinical Alzheimer's disease patients. This was also the case for memory problems, 89% in frontotemporal dementia and 100% in clinical Alzheimer's disease patients. Median age at death was significantly lower in patients with frontotemporal dementia (68 years) compared to clinical Alzheimer's disease patients (79 years), although the sizes of the sub-cohorts are limited and do not allow prognostic predictions. Post-mortem brain analysis of one p.R406W patient with behavioural variant frontotemporal dementia revealed frontotemporal lobar degeneration with tau pathology. Notably, neuropathological investigation showed only 3R tau isoforms in the absence of 4R tau reactivity, an unusual finding in microtubule-associated protein tau-related frontotemporal lobar degeneration. No traces of amyloid pathology were present. Prevalence of the p.R406W mutation was relatively high in both frontotemporal dementia and Alzheimer's disease Belgian patient cohorts. These findings grant new insights into genotype-phenotype correlations of p.R406W carriers. They may help in further unravelling of the pathophysiology of this tauopathy and in facilitating the identification of patients with p.R406W-related frontotemporal lobar degeneration, both in clinical diagnostic and research settings.
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Enfermedad de Alzheimer , Demencia Frontotemporal , Degeneración Lobar Frontotemporal , Enfermedad de Pick , Humanos , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/genética , Demencia Frontotemporal/diagnóstico por imagen , Demencia Frontotemporal/genética , Demencia Frontotemporal/patología , Proteínas tau/genética , Degeneración Lobar Frontotemporal/patología , Mutación/genética , Fenotipo , BiomarcadoresRESUMEN
Neurodegenerative diseases (NDDs) form a heterogeneous, widespread group of disorders, generally characterized by progressive cognitive decline and neuropsychiatric disturbances. One of the abilities that seems particularly vulnerable to the impairments in neurodegenerative diseases is the capability to manage one's personal finances. Indeed, people living with neurodegenerative diseases were shown to consistently present with more problems on performance-based financial tasks than healthy individuals. While objective, performance-based tasks provide insight into the financial competence of people living with neurodegenerative diseases in a controlled, standardized setting; relatively little can be said, based on these tasks, about their degree of success in dealing with the financial demands, issues, or questions of everyday life (i.e., financial performance). The aim of this systematic review is to provide an overview of the literature examining self and informant reports of financial performance in people living with neurodegenerative diseases. In total, 22 studies were included that compared the financial performance of people living with mild cognitive impairment (MCI), Alzheimer's disease (AD), Parkinson's disease, or multiple sclerosis to a (cognitively) normal control group. Overall, the results indicate that people living with neurodegenerative diseases are more vulnerable to impairments in financial performance than cognitively normal individuals and that the degree of reported problems seems to be related to the severity of cognitive decline. As the majority of studies however focused on MCI or AD and made use of limited assessment methods, future research should aim to develop and adopt more comprehensive assessments to study strengths and weaknesses in financial performance of people living with different neurodegenerative diseases.
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Alzheimer's disease CSF biomarkers 42 amino acid long amyloid-ß peptide (Aß1-42), total tau protein (T-tau), and tau protein phosphorylated at threonine 181 (P-tau181) are considered surrogate biomarkers of Alzheimer's disease pathology, and significantly improve diagnostic accuracy. Their ability to reflect neuropathological changes later in the disease course is not well characterized. This study aimed to assess the potential of CSF biomarkers measured in mid to late stage Alzheimer's disease to reflect post-mortem neuropathological changes. Individuals were selected from two autopsy cohorts of Alzheimer's disease patients in Antwerp and Amsterdam. Neuropathological diagnosis was performed according to the updated consensus National Institute on Aging-Alzheimer's Association guidelines, which includes quantification of amyloid-ß plaque, neurofibrillary tangle, and neuritic plaque load. CSF samples were analysed for Aß1-42, T-tau, and P-tau181 by ELISA. One hundred and fourteen cases of pure definite Alzheimer's disease were included in the study (mean age 74 years, disease duration 6 years at CSF sampling, 50% females). Median interval between CSF sampling and death was 1 year. We found no association between Aß1-42 and Alzheimer's disease neuropathological change profile. In contrast, an association of P-tau181 and T-tau with Alzheimer's disease neuropathological change profile was observed. P-tau181 was associated with all three individual Montine scores, and the associations became stronger and more significant as the interval between lumbar puncture and death increased. T-tau was also associated with all three Montine scores, but in individuals with longer intervals from lumbar puncture to death only. Stratification of the cohort according to APOE ε4 carrier status revealed that the associations applied mostly to APOE ε4 non-carriers. Our data suggest that similar to what has been reported for Aß1-42, plateau levels of P-tau181 and T-tau are reached during the disease course, albeit at later disease stages, reducing the potential of tau biomarkers to monitor Alzheimer's disease pathology as the disease progresses. As a consequence, CSF biomarkers, which are performant for clinical diagnosis of early Alzheimer's disease, may not be well suited for staging or monitoring Alzheimer's disease pathology as it progresses through later stages.
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Enfermedad de Alzheimer , Proteínas tau , Femenino , Humanos , Anciano , Masculino , Proteínas tau/líquido cefalorraquídeo , Enfermedad de Alzheimer/patología , Apolipoproteína E4 , Péptidos beta-Amiloides/líquido cefalorraquídeo , Placa Amiloide , Biomarcadores/líquido cefalorraquídeo , Progresión de la Enfermedad , Treonina , Fragmentos de Péptidos/líquido cefalorraquídeoRESUMEN
OBJECTIVES: Delirium frequently arises in older demented and non-demented patients in postoperative, clinical settings. To date, the underlying pathophysiological mechanisms remain poorly understood. Monoamine neurotransmitter alterations have been linked to delirium and cognitive impairment. Our aim was to investigate if this holds true in cognitively normal and impaired patients experiencing delirium following hip surgery. METHODS: Monoamines and metabolites were measured in plasma samples of 181 individuals by means of reversed-phase ultra-high-performance liquid chromatography with electrochemical detection. Delirium and delirium severity were scored with the Confusion Assessment Method and Delirium Rating Scale-Revised-1998. Cognitive function was assessed using the Informant Questionnaire on Cognitive Decline and the Mini-Mental State Examination, multimorbidity with the Charlson Comorbidity Index. RESULTS: Plasma 5-hydroxyindoleacetic acid (5-HIAA), the major metabolite of serotonin (5-HT), was significantly higher in delirious and non-delirious cognitively impaired subjects as compared to control individuals without delirium and cognitive impairment (p < 0.001 and p = 0.007), which remained highly significant after excluding patients taking psychotropic medication (p < 0.0001 and p = 0.003). No significant differences were found for cognitively normal delirious patients, although serotonergic levels were numerically higher compared to control counterparts. CONCLUSIONS: Our findings indicate a general serotonergic disturbance in delirious and non-delirious postoperative patients suffering from cognitive impairment. We observed a similar, but less pronounced difference in delirious patients, which suggests serotonergic disturbances may be further aggravated by the co-occurrence of delirium and cognitive impairment.
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Delirio , Anciano , Cognición , Humanos , Ácido HidroxiindolacéticoRESUMEN
BACKGROUND: Dementia is increasingly prevalent in people with severe/profound intellectual disabilities. However, early detection and diagnosis of dementia is complex in this population. This study aimed to identify observable dementia symptoms in adults with severe/profound intellectual disabilities in available literature. METHOD: A systematic literature search was conducted in PubMed, PsycINFO and Web of Science with an exhaustive search string using a combination of search terms for severe/profound intellectual disabilities and dementia/ageing. RESULTS: Eleven studies met inclusion criteria. Cognitive decline, behavioural and psychological alterations, decline in activities of daily living as well as neurological and physical changes were found. CONCLUSIONS: Only a very limited number of studies reported symptoms ascribed to dementia in adults with severe/profound intellectual disabilities. Given the complexity of signalling and diagnosing dementia, dedicated studies are required to unravel the natural history of dementia in this population.
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Demencia , Discapacidad Intelectual , Actividades Cotidianas , Humanos , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/epidemiologíaRESUMEN
Alzheimer's disease (AD) is the most prevalent form of dementia and is characterized by abnormal extracellular aggregates of amyloid-ß and intraneuronal hyperphosphorylated tau tangles and neuropil threads. Microglia, the tissue-resident macrophages of the central nervous system (CNS), are important for CNS homeostasis and implicated in AD pathology. In amyloid mouse models, a phagocytic/activated microglia phenotype has been identified. How increasing levels of amyloid-ß and tau pathology affect human microglia transcriptional profiles is unknown. Here, we performed snRNAseq on 482,472 nuclei from non-demented control brains and AD brains containing only amyloid-ß plaques or both amyloid-ß plaques and tau pathology. Within the microglia population, distinct expression profiles were identified of which two were AD pathology-associated. The phagocytic/activated AD1-microglia population abundance strongly correlated with tissue amyloid-ß load and localized to amyloid-ß plaques. The AD2-microglia abundance strongly correlated with tissue phospho-tau load and these microglia were more abundant in samples with overt tau pathology. This full characterization of human disease-associated microglia phenotypes provides new insights in the pathophysiological role of microglia in AD and offers new targets for microglia-state-specific therapeutic strategies.
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Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Microglía/patología , Proteínas tau/metabolismo , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Femenino , Humanos , MasculinoRESUMEN
Increasing epidemiological evidence highlights the association between systemic insulin resistance and Alzheimer's disease (AD). As insulin resistance can be caused by high-stress hormone levels and since hypercortisolism appears to be an important risk factor of AD, we aimed to investigate the systemic insulin functionality and circulating stress hormone levels in a mutant humanized amyloid precursor protein (APP) overexpressing (hAPP23+/-) AD mouse model. Memory and spatial learning of male hAPP23+/- and C57BL/6 (wild type, WT) mice were assessed by a Morris Water Maze (MWM) test at the age of 4 and 12 months. The systemic metabolism was examined by intraperitoneal glucose and insulin tolerance tests (GTT, ITT). Insulin and corticosterone levels were determined in serum. In the hippocampus, parietal and occipital cortex of hAPP23+/- brains, amyloid-beta (Aß) deposits were present at 12 months of age. MWM demonstrated a cognitive decline in hAPP23+/- mice at 12 but not at 4 months, evidenced by increasing total path lengths and deteriorating probe trials compared to WT mice. hAPP23+/- animals presented increased serum corticosterone levels compared to WT mice at both 4 and 12 months. hAPP23+/- mice exhibited peripheral insulin resistance compared to WT mice at 4 months, which stabilized at 12 months of age. Serum insulin levels were similar between genotypes at 4 months of age but were significantly higher in hAPP23+/- mice at 12 months of age. Peripheral glucose homeostasis remained unchanged. These results indicate that peripheral insulin resistance combined with elevated circulating stress hormone levels could be potential biomarkers of the pre-symptomatic phase of AD.
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Enfermedad de Alzheimer/sangre , Biomarcadores/sangre , Disfunción Cognitiva , Corticosterona/sangre , Resistencia a la Insulina , Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/etiología , Enfermedad de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animales , Síndrome de Cushing/complicaciones , Modelos Animales de Enfermedad , Insulina/sangre , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones TransgénicosRESUMEN
BACKGROUND: Differentiating dementia from baseline level of functioning is difficult among people with severe/profound intellectual (and multiple) disabilities. Moreover, studies on observable dementia symptoms are scarce. This study examined (a) the relevance of dementia diagnosis, (b) observable symptoms and (c) training/information needs. METHODS: Four explorative focus groups were held with care professionals and family members who have experience with people with severe/profound intellectual (and multiple) disabilities (≥40 years) and decline/dementia. RESULTS: Thematic analysis showed that participants wanted to know about a dementia diagnosis for a better understanding and to be able to make informed choices (question 1). Using a categorisation matrix, cognitive and behavioural changes were shown to be most prominent (question 2). Participants indicated that they needed enhanced training, more knowledge development and translation, and supportive organisational choices/policies (question 3). CONCLUSIONS: Timely identifying/diagnosing dementia allows for a timely response to changing needs. This requires a better understanding of symptoms.
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Demencia , Personas con Discapacidad , Discapacidad Intelectual , Demencia/diagnóstico , Familia , Grupos Focales , Humanos , Discapacidad Intelectual/diagnósticoRESUMEN
Exploring the neurochemical continuum between frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) with respect to monoamines and kynurenines in cerebrospinal fluid (CSF) and serum, may be useful to identify possible new research/therapeutic targets. Hence, we analysed monoamines and kynurenines in CSF and serum derived from patients with FTD (n = 39), ALS (n = 23), FTD-ALS (n = 4) and age-matched control subjects (n = 26), using reversed-phase ultra-high performance liquid chromatography (RP-UHPLC) with electrochemical detection (ECD) and liquid chromatography tandem mass spectrometry, respectively. We noted a shared dopaminergic disturbance in FTD and ALS when compared to CONTR, with significantly increased serum DA levels and decreased DOPAC concentrations, as well as decreased DOPAC/DA ratios in both disease groups. In CSF, significantly reduced DOPAC concentrations in FTD and ALS were observed as well. Here, a significant increase in DA levels and decrease in DOPAC/DA ratios was only found in FTD relative to CONTR. With respect to the kynurenine pathway (KP), we only found decreased HK/XA ratios, indicative for vitamin B6 status, in serum of ALS subjects compared to FTD. The dopaminergic commonalities observed in FTD and ALS might relate to a disturbance of dopaminergic nerve terminals in projection areas of the substantia nigra and/or ventral tegmental area, although these findings should first be confirmed in brain tissue. Lastly, based on the results of this work, the KP does not hold promise as a research/therapeutic target in FTD and ALS.
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Esclerosis Amiotrófica Lateral/metabolismo , Monoaminas Biogénicas/metabolismo , Demencia Frontotemporal/metabolismo , Quinurenina/metabolismo , Anciano , Esclerosis Amiotrófica Lateral/sangre , Esclerosis Amiotrófica Lateral/líquido cefalorraquídeo , Monoaminas Biogénicas/sangre , Monoaminas Biogénicas/líquido cefalorraquídeo , Biomarcadores/sangre , Biomarcadores/líquido cefalorraquídeo , Femenino , Demencia Frontotemporal/sangre , Demencia Frontotemporal/líquido cefalorraquídeo , Humanos , Quinurenina/sangre , Quinurenina/líquido cefalorraquídeo , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
The kynurenine (Kyn) pathway, which regulates neuroinflammation and N-methyl-d-aspartate receptor activation, is implicated in Parkinson's disease (PD) and Alzheimer's disease (AD). Age-related changes in Kyn metabolism and altered cerebral Kyn uptake along large neutral amino acid transporters, could contribute to these diseases. To gain further insight into the role and prognostic potential of the Kyn pathway in PD and AD, we investigated systemic and cerebral Kyn metabolite production and estimations of their transporter-mediated uptake in the brain. Kyn metabolites and large neutral amino acids were retrospectively measured in serum and cerebrospinal fluid (CSF) of clinically well-characterized PD patients (n = 33), AD patients (n = 33), and age-matched controls (n = 39) using solid-phase extraction-liquid chromatographic-tandem mass spectrometry. Aging was disease independently associated with increased Kyn, kynurenic acid and quinolinic acid in serum and CSF. Concentrations of kynurenic acid were reduced in CSF of PD and AD patients (p = 0.001; p = 0.002) but estimations of Kyn brain uptake did not differ between diseased and controls. Furthermore, serum Kyn and quinolinic acid levels strongly correlated with their respective content in CSF and Kyn in serum negatively correlated with AD disease severity (p = 0.002). Kyn metabolites accumulated with aging in serum and CSF similarly in PD patients, AD patients, and control subjects. In contrast, kynurenic acid was strongly reduced in CSF of PD and AD patients. Differential transporter-mediated Kyn uptake is unlikely to majorly contribute to these cerebral Kyn pathway disturbances. We hypothesize that the combination of age- and disease-specific changes in cerebral Kyn pathway activity could contribute to reduced neurogenesis and increased excitotoxicity in neurodegenerative disease.
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Enfermedad de Alzheimer/metabolismo , Quinurenina/metabolismo , Enfermedad de Parkinson/metabolismo , Anciano , Envejecimiento/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used to assess the neural correlates of anosognosia in mild cognitive impairment (MCI) and Alzheimer's disease (AD). A systematic review of this literature was performed, following the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement, on PubMed, EMBASE, and PsycINFO databases. Twenty-five articles met all inclusion criteria. Specifically, four brain connectivity and 21 brain perfusion, metabolism, and activation articles. Anosognosia is associated in MCI with frontal lobe and cortical midline regional dysfunction (reduced perfusion and activation), and with reduced parietotemporal metabolism. Reduced within and between network connectivity is observed in the default mode network regions of AD patients with anosognosia compared to AD patients without anosognosia and controls. During initial stages of cognitive decline in anosognosia, reduced indirect neural activity (i.e. perfusion, metabolism, and activation) is associated with the cortical midline regions, followed by the parietotemporal structures in later stages and culminating in frontotemporal dysfunction. Although the current evidence suggests differences in activation between AD or MCI patients with anosognosia and healthy controls, more evidence is needed exploring the differences between MCI and AD patients with and without anosognosia using resting state and task related paradigms.
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Agnosia/fisiopatología , Enfermedad de Alzheimer/fisiopatología , Encéfalo/fisiopatología , Disfunción Cognitiva/fisiopatología , Agnosia/complicaciones , Agnosia/diagnóstico por imagen , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/diagnóstico por imagen , Disfunción Cognitiva/complicaciones , Disfunción Cognitiva/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Vías Nerviosas/fisiopatología , Tomografía de Emisión de Positrones , Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
BACKGROUND: Lipocalin 2 (Lcn2) is an acute-phase protein implicated in multiple neurodegenerative conditions. Interestingly, both neuroprotective and neurodegenerative effects have been described for Lcn2. Increased Lcn2 levels were found in human post-mortem Alzheimer (AD) brain tissue, and in vitro studies indicated that Lcn2 aggravates amyloid-ß-induced toxicity. However, the role of Lcn2 has not been studied in an in vivo AD model. Therefore, in the current study, the effects of Lcn2 were studied in the J20 mouse model of AD. METHODS: J20 mice and Lcn2-deficient J20 (J20xLcn2 KO) mice were compared at the behavioral and neuropathological level. RESULTS: J20xLcn2 KO and J20 mice presented equally strong AD-like behavioral changes, cognitive impairment, plaque load, and glial activation. Interestingly, hippocampal iron accumulation was significantly decreased in J20xLcn2 KO mice as compared to J20 mice. CONCLUSIONS: Lcn2 contributes to AD-like brain iron dysregulation, and future research should further explore the importance of Lcn2 in AD.
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Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Trastornos del Conocimiento/etiología , Regulación de la Expresión Génica/genética , Hierro/metabolismo , Lipocalina 2/metabolismo , Enfermedad de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Proteínas de Unión al Calcio/metabolismo , Modelos Animales de Enfermedad , Conducta Exploratoria/fisiología , Proteína Ácida Fibrilar de la Glía/metabolismo , Lipocalina 2/genética , Masculino , Aprendizaje por Laberinto , Trastornos de la Memoria/etiología , Ratones , Ratones Transgénicos , Proteínas de Microfilamentos/metabolismo , Mutación/genética , Neuroglía/patología , Fosfopiruvato Hidratasa/metabolismo , Placa Amiloide/etiología , Placa Amiloide/metabolismoRESUMEN
Mutations leading to premature termination codons in ATP-Binding Cassette Subfamily A Member 7 (ABCA7) are high penetrant risk factors of Alzheimer's disease (AD). The influence of other genetic variants in ABCA7 and downstream functional mechanisms, however, is poorly understood. To address this knowledge gap, we investigated tandem repetitive regions in ABCA7 in a Belgian cohort of 1529 AD patients and control individuals and identified an intronic variable number tandem repeat (VNTR). We observed strong association between VNTR length and a genome-wide associated signal for AD in the ABCA7 locus. Expanded VNTR alleles were highly enriched in AD patients [odds ratio = 4.5 (1.3-24.2)], and VNTR length inversely correlated with amyloid ß1-42 in cerebrospinal fluid and ABCA7 expression. In addition, we identified three novel ABCA7 alternative splicing events. One isoform in particular-which is formed through exon 19 skipping-lacks the first nucleotide binding domain of ABCA7 and is abundant in brain tissue. We observed a tight correlation between exon 19 skipping and VNTR length. Our findings underline the importance of studying repetitive DNA in complex disorders and expand the contribution of genetic and transcript variation in ABCA7 to AD.
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Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Empalme Alternativo/genética , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Repeticiones de Minisatélite , Anciano , Anciano de 80 o más Años , Biomarcadores/líquido cefalorraquídeo , Encéfalo/metabolismo , Exones , Femenino , Expresión Génica , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Intrones , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Isoformas de Proteínas/metabolismoRESUMEN
Dementia is a risk factor for unsafe driving. Therefore, an assessment strategy has recently been developed for the prediction of fitness to drive in patients with the Alzheimer disease (AD). The aim of this study was to investigate whether this strategy is also predictive of fitness to drive in patients with non-AD dementia, that is, vascular dementia, frontotemporal dementia, and dementia with Lewy bodies. Predictors were derived from 3 types of assessment: clinical interviews, neuropsychological tests, and driving simulator rides. The criterion was the pass-fail outcome of an official on-road driving assessment. About half of the patients with non-AD dementia (n=34) failed the on-road driving assessment. Neuropsychological assessment [area under the curve (AUC)=0.786] was significantly predictive of fitness to drive in patients with non-AD dementia, however, clinical interviews (AUC=0.559) and driving simulator rides (AUC=0.404) were not. The fitness-to-drive assessment strategy with the 3 types of assessment combined (AUC=0.635) was not found to significantly predict fitness to drive in non-AD dementia. Different types of dementia require different measures and assessment strategies.
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Enfermedad de Alzheimer/clasificación , Examen de Aptitud para la Conducción de Vehículos , Conducción de Automóvil/psicología , Anciano , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas/estadística & datos numéricos , Tiempo de ReacciónRESUMEN
BACKGROUND: Driving is related to social participation; therefore older drivers may be reluctant to cease driving. Continuation of driving has also been reported in a large proportion of patients with cognitive impairment. The aim of this study is to investigate whether patients with cognitive impairment adhere to driving cessation advice after a fitness-to-drive assessment and what the consequences are with regard to mobility. METHODS: Patients with cognitive impairment (n = 172) participated in a fitness-to-drive assessment study, including an on-road driving assessment. Afterwards, patients were advised to either continue driving, to follow driving lessons, or to cease driving. Approximately seven months thereafter, patients were asked in a follow-up interview about their adherence to the driving recommendation. Factors influencing driving cessation were identified using a binary logistic regression analysis. Use of alternative transportation was also evaluated. RESULTS: Respectively 92 and 79% of the patients adhered to the recommendation to continue or cease driving. Female gender, a higher Clinical Dementia Rating-score, perceived health decline, and driving cessation advice facilitated driving cessation. Patients who ceased driving made use of less alternative modes of transportation than patients who still drove. Nonetheless, around 40% of the patients who ceased driving increased their frequency of cycling and/or public transport use. CONCLUSIONS: Adherence to the recommendations given after the fitness-to-drive assessments was high. Female patients were in general more likely to cease driving. However, a minority of patients did not adhere to driving cessation advice. These drivers with dementia should be made aware of the progression of their cognitive impairment and general health decline to facilitate driving cessation. There are large differences in mobility between patients with cognitive impairment. Physicians should discuss options for alternative transportation in order to promote sustained safe mobility of patients with cognitive impairment.
Asunto(s)
Accidentes de Tránsito/prevención & control , Accidentes de Tránsito/psicología , Conducción de Automóvil/psicología , Disfunción Cognitiva/psicología , Anciano , Anciano de 80 o más Años , Disfunción Cognitiva/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Transportes/métodosRESUMEN
BACKGROUND: In dementia, apathy and depression are often seen as one disorder because of the many overlapping symptoms. However, for therapy a correct differentiation is essential. Moreover, apathy and depression are likely both associated with different cognitive deficits and progression of the disease. In this research we give an overview of cognitive domains associated with apathy and depression in MCI patients and report how often both disorders occur in a population sample. METHOD: We administered the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to 117 cognitively healthy controls (GC), 97 patients with mild cognitive impairment (MCI) and 50 patients with dementia (DEM). In addition, the Apathy Evaluation Scale clinical version (AES-C) and the Geriatric Depression Scale (GDS) were administered. RESULTS: The number of patients with apathy increased with cognitive decline with respectively 3.4%, 10.4% and 41.5% of patients in the GC, MCI and DEM group. The prevalence of isolated depression was highest in the MCI group (18.8%). Correlation analyses in the MCI group showed that apathy and not depression was associated with a deficit in encoding, attention and global cognitive functioning. CONCLUSION: The prevalence of apathy and depressive symptoms is different in patients with MCI, DEM and GC, and within the MCI group apathy and depression are associated with different cognitive domains.
Asunto(s)
Apatía , Cognición/fisiología , Disfunción Cognitiva/epidemiología , Demencia/psicología , Anciano , Trastornos del Conocimiento/epidemiología , Trastornos del Conocimiento/psicología , Disfunción Cognitiva/psicología , Trastorno Depresivo/epidemiología , Femenino , Humanos , Masculino , Escalas de Valoración PsiquiátricaRESUMEN
Behavioral and psychological symptoms of dementia (BPSD) have not been comprehensively studied in people with Down syndrome, despite their high risk on dementia. A novel evaluation scale was developed to identify the nature, frequency and severity of behavioral changes (83 behavioral items in 12 clinically defined sections). Central aim was to identify items that change in relation to the dementia status. Structured interviews were conducted with informants of people with Down syndrome without dementia (DS, Nâ¯= 149), with questionable dementia (DSâ¯+ TD, Nâ¯= 65) and with diagnosed dementia (DSâ¯+ AD, Nâ¯= 67). Group comparisons showed a pronounced increase in frequency and severity of items about anxiety, sleep disturbances, agitation & stereotypical behavior, aggression, apathy, depressive symptoms, and, eating/drinking behavior. The proportion of individuals presenting an increase was highest in the DSâ¯+ AD group and lowest in the DS group. Interestingly, among DSâ¯+ TD individuals, a substantial proportion already presented increased anxiety, sleep disturbances, apathy and depressive symptoms, suggesting that these changes may be early alarm signals of dementia. The scale may contribute to a better understanding of the changes, adapting daily care/support, and providing suitable therapies to people with Down syndrome. The scale needs to be optimized based on the results and experiences. The applicability, reliability and validity require further study.