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1.
Cell Rep ; 43(2): 113691, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38244198

RESUMEN

Amyloid-ß (Aß) and tau proteins accumulate within distinct neuronal systems in Alzheimer's disease (AD). Although it is not clear why certain brain regions are more vulnerable to Aß and tau pathologies than others, gene expression may play a role. We study the association between brain-wide gene expression profiles and regional vulnerability to Aß (gene-to-Aß associations) and tau (gene-to-tau associations) pathologies by leveraging two large independent AD cohorts. We identify AD susceptibility genes and gene modules in a gene co-expression network with expression profiles specifically related to regional vulnerability to Aß and tau pathologies in AD. In addition, we identify distinct biochemical pathways associated with the gene-to-Aß and the gene-to-tau associations. These findings may explain the discordance between regional Aß and tau pathologies. Finally, we propose an analytic framework, linking the identified gene-to-pathology associations to cognitive dysfunction in AD at the individual level, suggesting potential clinical implication of the gene-to-pathology associations.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Transcriptoma/genética , Enfermedad de Alzheimer/genética , Perfilación de la Expresión Génica , Péptidos beta-Amiloides , Disfunción Cognitiva/genética
2.
medRxiv ; 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-38106123

RESUMEN

The BrainAGE method is used to estimate biological brain age using structural neuroimaging. However, the stability of the model across different scan parameters and races/ethnicities has not been thoroughly investigated. Estimated brain age was compared within- and across- MRI field strength and across voxel sizes. Estimated brain age gap (BAG) was compared across demographically matched groups of different self-reported races and ethnicities in ADNI and IMAS cohorts. Longitudinal ComBat was used to correct for potential scanner effects. The brain age method was stable within field strength, but less stable across different field strengths. The method was stable across voxel sizes. There was a significant difference in BAG between races, but not ethnicities. Correction procedures are suggested to eliminate variation across scanner field strength while maintaining accurate brain age estimation. Further studies are warranted to determine the factors contributing to racial differences in BAG.

3.
medRxiv ; 2023 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-37645867

RESUMEN

Amyloid-ß (Aß) and tau proteins accumulate within distinct neuronal systems in Alzheimer's disease (AD). Although it is not clear why certain brain regions are more vulnerable to Aß and tau pathologies than others, gene expression may play a role. We studied the association between brain-wide gene expression profiles and regional vulnerability to Aß (gene-to-Aß associations) and tau (gene-to-tau associations) pathologies leveraging two large independent cohorts (n = 715) of participants along the AD continuum. We identified several AD susceptibility genes and gene modules in a gene co-expression network with expression profiles related to regional vulnerability to Aß and tau pathologies in AD. In particular, we found that the positive APOE -to-tau association was only seen in the AD cohort, whereas patients with AD and frontotemporal dementia shared similar positive MAPT -to-tau association. Some AD candidate genes showed sex-dependent negative gene-to-Aß and gene-to-tau associations. In addition, we identified distinct biochemical pathways associated with the gene-to-Aß and the gene-to-tau associations. Finally, we proposed a novel analytic framework, linking the identified gene-to-pathology associations to cognitive dysfunction in AD at the individual level, suggesting potential clinical implication of the gene-to-pathology associations. Taken together, our study identified distinct gene expression profiles and biochemical pathways that may explain the discordance between regional Aß and tau pathologies, and filled the gap between gene-to-pathology associations and cognitive dysfunction in individual AD patients that may ultimately help identify novel personalized pathogenetic biomarkers and therapeutic targets. One Sentence Summary: We identified replicable cognition-related associations between regional gene expression profiles and selectively regional vulnerability to amyloid-ß and tau pathologies in AD.

4.
Neurobiol Aging ; 130: 103-113, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37499587

RESUMEN

Identification of biomarkers for the early stages of Alzheimer's disease (AD) is an imperative step in developing effective treatments. Cerebral blood flow (CBF) is a potential early biomarker for AD; generally, older adults with AD have decreased CBF compared to normally aging peers. CBF deviates as the disease process and symptoms progress. However, further characterization of the relationships between CBF and AD risk factors and pathologies is still needed. We assessed the relationships between CBF quantified by arterial spin-labeled magnetic resonance imaging, hypertension, APOEε4, and tau and amyloid positron emission tomography in 77 older adults: cognitively normal, subjective cognitive decline, and mild cognitive impairment. Tau and amyloid aggregation were related to altered CBF, and some of these relationships were dependent on hypertension or APOEε4 status. Our findings suggest a complex relationship between risk factors, AD pathologies, and CBF that warrants future studies of CBF as a potential early biomarker for AD.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Anciano , Humanos , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides , Proteínas Amiloidogénicas , Biomarcadores , Circulación Cerebrovascular/fisiología , Disfunción Cognitiva/diagnóstico por imagen , Imagen por Resonancia Magnética , Tomografía de Emisión de Positrones , Factores de Riesgo , Proteínas tau
5.
Eur J Nucl Med Mol Imaging ; 50(9): 2669-2682, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37017737

RESUMEN

PURPOSE: Pittsburgh Compound-B (11C-PiB) and 18F-florbetapir are amyloid-ß (Aß) positron emission tomography (PET) radiotracers that have been used as endpoints in Alzheimer's disease (AD) clinical trials to evaluate the efficacy of anti-Aß monoclonal antibodies. However, comparing drug effects between and within trials may become complicated if different Aß radiotracers were used. To study the consequences of using different Aß radiotracers to measure Aß clearance, we performed a head-to-head comparison of 11C-PiB and 18F-florbetapir in a Phase 2/3 clinical trial of anti-Aß monoclonal antibodies. METHODS: Sixty-six mutation-positive participants enrolled in the gantenerumab and placebo arms of the first Dominantly Inherited Alzheimer Network Trials Unit clinical trial (DIAN-TU-001) underwent both 11C-PiB and 18F-florbetapir PET imaging at baseline and during at least one follow-up visit. For each PET scan, regional standardized uptake value ratios (SUVRs), regional Centiloids, a global cortical SUVR, and a global cortical Centiloid value were calculated. Longitudinal changes in SUVRs and Centiloids were estimated using linear mixed models. Differences in longitudinal change between PET radiotracers and between drug arms were estimated using paired and Welch two sample t-tests, respectively. Simulated clinical trials were conducted to evaluate the consequences of some research sites using 11C-PiB while other sites use 18F-florbetapir for Aß PET imaging. RESULTS: In the placebo arm, the absolute rate of longitudinal change measured by global cortical 11C-PiB SUVRs did not differ from that of global cortical 18F-florbetapir SUVRs. In the gantenerumab arm, global cortical 11C-PiB SUVRs decreased more rapidly than global cortical 18F-florbetapir SUVRs. Drug effects were statistically significant across both Aß radiotracers. In contrast, the rates of longitudinal change measured in global cortical Centiloids did not differ between Aß radiotracers in either the placebo or gantenerumab arms, and drug effects remained statistically significant. Regional analyses largely recapitulated these global cortical analyses. Across simulated clinical trials, type I error was higher in trials where both Aß radiotracers were used versus trials where only one Aß radiotracer was used. Power was lower in trials where 18F-florbetapir was primarily used versus trials where 11C-PiB was primarily used. CONCLUSION: Gantenerumab treatment induces longitudinal changes in Aß PET, and the absolute rates of these longitudinal changes differ significantly between Aß radiotracers. These differences were not seen in the placebo arm, suggesting that Aß-clearing treatments may pose unique challenges when attempting to compare longitudinal results across different Aß radiotracers. Our results suggest converting Aß PET SUVR measurements to Centiloids (both globally and regionally) can harmonize these differences without losing sensitivity to drug effects. Nonetheless, until consensus is achieved on how to harmonize drug effects across radiotracers, and since using multiple radiotracers in the same trial may increase type I error, multisite studies should consider potential variability due to different radiotracers when interpreting Aß PET biomarker data and, if feasible, use a single radiotracer for the best results. TRIAL REGISTRATION: ClinicalTrials.gov NCT01760005. Registered 31 December 2012. Retrospectively registered.


Asunto(s)
Enfermedad de Alzheimer , Humanos , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/metabolismo , Tomografía de Emisión de Positrones/métodos , Compuestos de Anilina , Glicoles de Etileno , Encéfalo/metabolismo
6.
medRxiv ; 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36993271

RESUMEN

Determining the genetic architecture of Alzheimer's disease (AD) pathologies can enhance mechanistic understanding and inform precision medicine strategies. Here, we performed a genome-wide association study of cortical tau quantified by positron emission tomography in 3,136 participants from 12 independent studies. The CYP1B1-RMDN2 locus was associated with tau deposition. The most significant signal was at rs2113389, which explained 4.3% of the variation in cortical tau, while APOE4 rs429358 accounted for 3.6%. rs2113389 was associated with higher tau and faster cognitive decline. Additive effects, but no interactions, were observed between rs2113389 and diagnosis, APOE4 , and Aß positivity. CYP1B1 expression was upregulated in AD. rs2113389 was associated with higher CYP1B1 expression and methylation levels. Mouse model studies provided additional functional evidence for a relationship between CYP1B1 and tau deposition but not Aß. These results may provide insight into the genetic basis of cerebral tau and novel pathways for therapeutic development in AD.

7.
J Alzheimers Dis ; 91(2): 743-752, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36502316

RESUMEN

BACKGROUND: The eye has been considered a 'window to the brain,' and several neurological diseases including neurodegenerative conditions like Alzheimer's disease (AD) also show changes in the retina. OBJECTIVE: To investigate retinal nerve fiber layer (RNFL) thickness and its association with brain volume via magnetic resonance imaging (MRI) in older adults with subjective or objective cognitive decline. METHODS: 75 participants underwent ophthalmological and neurological evaluation including optical coherence tomography and MRI (28 cognitively normal subjects, 26 with subjective cognitive decline, 17 patients diagnosed with mild cognitive impairment, and 4 with AD). Differences in demographics, thickness of RNFL, and brain volume were assessed using ANCOVA, while partial Pearson correlations, covaried for age and sex, were used to compare thickness of the peripapillary RNFL with brain volumes, with p < 0.05 considered statistically significant. RESULTS: Mean RNFL thickness was significantly correlated with brain volumes, including global volume (right eye r = 0.235 p = 0.046, left eye r = 0.244, p = 0.037), temporal lobe (right eye r = 0.242 p = 0.039, left eye r = 0.290, p = 0.013), hippocampal (right eye r = 0.320 p = 0.005, left eye r = 0.306, p = 0.008), amygdala (left eye r = 0.332, p = 0.004), and occipital lobe (right eye r = 0.264 p = 0.024) volumes. CONCLUSION: RNFL thickness in both eyes was positively associated with brain volumes in subjects with subjective and objective cognitive decline. The RNFL, however, did not correlate with the disease, but the small sample number makes it important to conduct larger studies. RNFL thickness may be a useful non-invasive and inexpensive tool for detection of brain neurodegeneration and may assist with diagnosis and monitoring of progression and treatment in AD.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Anciano , Enfermedad de Alzheimer/patología , Fibras Nerviosas/patología , Retina/diagnóstico por imagen , Retina/patología , Disfunción Cognitiva/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Tomografía de Coherencia Óptica/métodos
8.
J Alzheimers Dis ; 87(2): 761-769, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35367962

RESUMEN

BACKGROUND: Self and informant (proxy or study partner) reports of everyday cognitive functioning have been shown to be associated with incipient neurodegenerative disease. The 20-item Cognitive Change Index (CCI) and the 39-item Measurement of Everyday Cognition (ECog) were each developed to characterize early subjective changes in cognitive function. OBJECTIVE: We examined the relationship between CCI and ECog self and informant-based evaluations to determine content overlap and provide a co-calibration for converting between these widely used instruments. METHODS: 950 participants (57.1% female, mean age = 71.2 years) from ADNI and the Indiana ADRC with self-based evaluations and 279 participants (60.9% female, mean age = 71.8 years) with informant-based evaluations (Indiana ADRC) were included. Analyzed variables for the CCI and ECog included domain mean scores, memory domain total scores, and total scores for all items. Spearman correlations, regression analyses, and frequency distributions were used to assess the relationship between CCI and ECog. Sex, age, years of education, race/ethnicity, APOE ɛ4 carrier status, and baseline diagnosis were also analyzed as potentially relevant covariates. RESULTS: CCI and ECog total scores were highly correlated for the self (r = 0.795, p < 0.001) and informant-based (r = 0.840, p < 0.001) versions, as expected. Frequency distributions of self and informant total scores were generated and plotted separately. Quadratic regressions for self (r2 = 0.626) and informant (r2 = 0.741) scores were used to create a translation table between the CCI and ECog total scores. CONCLUSION: Self and informant total scores can be harmonized and translated between the CCI and ECog to facilitate cross-study and longitudinal assessment of perceived cognitive change, an important patient-reported outcome.


Asunto(s)
Disfunción Cognitiva , Enfermedades Neurodegenerativas , Anciano , Cognición , Disfunción Cognitiva/psicología , Autoevaluación Diagnóstica , Etnicidad , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas
9.
Alzheimers Dement (Amst) ; 13(1): e12230, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34466653

RESUMEN

INTRODUCTION: Head injuries (HI) are a risk factor for dementia, but the underlying etiology is not fully known. Understanding whether tau might mediate this relationship is important. METHODS: Cognition and tau deposition were compared between 752 individuals with (impaired, n = 302) or without cognitive impairment (CN, n = 450) with amyloid and [18F]flortaucipir positron emission tomography, HI history information, and cognitive testing from the Alzheimer's Disease Neuroimaging Initiative and the Indiana Memory and Aging Study. RESULTS: Sixty-three (38 CN, 25 impaired) reported a history of HI. Higher neuropsychiatric scores and poorer memory were observed in those with a history of HI. Tau was higher in individuals with a history of HI, especially those who experienced a loss of consciousness (LOC). Results were driven by impaired individuals, especially amyloid beta-positive individuals with history of HI with LOC. DISCUSSION: These findings suggest biological changes, such as greater tau, are associated with HI in individuals with cognitive impairment. Small effect sizes were observed; thus, further studies should replicate and extend these results.

10.
Nat Med ; 27(7): 1187-1196, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34155411

RESUMEN

Dominantly inherited Alzheimer's disease (DIAD) causes predictable biological changes decades before the onset of clinical symptoms, enabling testing of interventions in the asymptomatic and symptomatic stages to delay or slow disease progression. We conducted a randomized, placebo-controlled, multi-arm trial of gantenerumab or solanezumab in participants with DIAD across asymptomatic and symptomatic disease stages. Mutation carriers were assigned 3:1 to either drug or placebo and received treatment for 4-7 years. The primary outcome was a cognitive end point; secondary outcomes included clinical, cognitive, imaging and fluid biomarker measures. Fifty-two participants carrying a mutation were assigned to receive gantenerumab, 52 solanezumab and 40 placebo. Both drugs engaged their Aß targets but neither demonstrated a beneficial effect on cognitive measures compared to controls. The solanezumab-treated group showed a greater cognitive decline on some measures and did not show benefits on downstream biomarkers. Gantenerumab significantly reduced amyloid plaques, cerebrospinal fluid total tau, and phospho-tau181 and attenuated increases of neurofilament light chain. Amyloid-related imaging abnormalities edema was observed in 19.2% (3 out of 11 were mildly symptomatic) of the gantenerumab group, 2.5% of the placebo group and 0% of the solanezumab group. Gantenerumab and solanezumab did not slow cognitive decline in symptomatic DIAD. The asymptomatic groups showed no cognitive decline; symptomatic participants had declined before reaching the target doses.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Adulto , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/psicología , Péptidos beta-Amiloides/líquido cefalorraquídeo , Anticuerpos Monoclonales Humanizados/administración & dosificación , Biomarcadores/líquido cefalorraquídeo , Progresión de la Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Persona de Mediana Edad , Placebos
11.
Brain Connect ; 11(3): 239-249, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33430685

RESUMEN

Aim: Identify a global resting-state functional connectivity (gFC) signature in mutation carriers (MC) from the Dominantly Inherited Alzheimer Network (DIAN). Assess the gFC with regard to amyloid (A), tau (T), and neurodegeneration (N) biomarkers, and estimated years to symptom onset (EYO). Introduction: Cross-sectional measures were assessed in MC (n = 171) and mutation noncarrier (NC) (n = 70) participants. A functional connectivity (FC) matrix that encompassed multiple resting-state networks was computed for each participant. Methods: A global FC was compiled as a single index indicating FC strength. The gFC signature was modeled as a nonlinear function of EYO. The gFC was linearly associated with other biomarkers used for assessing the AT(N) framework, including cerebrospinal fluid (CSF), positron emission tomography (PET) molecular biomarkers, and structural magnetic resonance imaging. Results: The gFC was reduced in MC compared with NC participants. When MC participants were differentiated by clinical dementia rating (CDR), the gFC was significantly decreased in MC CDR >0 (demented) compared with either MC CDR 0 (cognitively normal) or NC participants. The gFC varied nonlinearly with EYO and initially decreased at EYO = -24 years, followed by a stable period followed by a further decline near EYO = 0 years. Irrespective of EYO, a lower gFC associated with values of amyloid PET, CSF Aß1-42, CSF p-tau, CSF t-tau, 18F-fluorodeoxyglucose, and hippocampal volume. Conclusions: The gFC correlated with biomarkers used for defining the AT(N) framework. A biphasic change in the gFC suggested early changes associated with CSF amyloid and later changes associated with hippocampal volume.


Asunto(s)
Enfermedad de Alzheimer , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/genética , Péptidos beta-Amiloides/metabolismo , Biomarcadores , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Estudios Transversales , Humanos , Imagen por Resonancia Magnética , Tomografía de Emisión de Positrones
12.
Neuropathology ; 40(6): 620-626, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32786148

RESUMEN

In this case report, we discuss a patient presenting with parkinsonism followed by a non-amnestic dementia with aphasic clinical features, as well as frontal dysexecutive syndrome. There was a family history of dementia with an autopsy diagnosis of "Pick's disease" in the proband's father. Neuroimaging of the patient revealed focal and severe temporal lobe and lesser frontoparietal lobe atrophy. At autopsy, there was severe frontotemporal lobar degeneration. Histologic evaluation revealed an absence of tau or transactivation response DNA-binding protein of 43 kDa (TDP) pathology but rather severe Lewy body deposition in the affected cortices. Genetic phenotyping revealed a novel missense mutation (p.E83Q) in exon 4 of the gene encoding α-synuclein (SNCA). This case study presents a patient with a novel SNCA E83Q mutation associated with widespread Lewy body pathology with prominent severe atrophy of the frontotemporal lobes and corresponding cognitive impairment.


Asunto(s)
Encéfalo/patología , Degeneración Lobar Frontotemporal/genética , Enfermedad por Cuerpos de Lewy/genética , alfa-Sinucleína/genética , Femenino , Degeneración Lobar Frontotemporal/patología , Humanos , Enfermedad por Cuerpos de Lewy/patología , Persona de Mediana Edad , Mutación , Mutación Missense
14.
Brain Commun ; 2(1): fcaa019, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32309804

RESUMEN

Visual deficits are common in neurodegenerative diseases including Alzheimer's disease. We sought to determine the association between visual contrast sensitivity and neuroimaging measures of Alzheimer's disease-related pathophysiology, including cerebral amyloid and tau deposition and neurodegeneration. A total of 74 participants (7 Alzheimer's disease, 16 mild cognitive impairment, 20 subjective cognitive decline, 31 cognitively normal older adults) underwent the frequency doubling technology 24-2 examination, a structural MRI scan and amyloid PET imaging for the assessment of visual contrast sensitivity. Of these participants, 46 participants (2 Alzheimer's disease, 9 mild cognitive impairment, 12 subjective cognitive decline, 23 cognitively normal older adults) also underwent tau PET imaging with [18F]flortaucipir. The relationships between visual contrast sensitivity and cerebral amyloid and tau, as well as neurodegeneration, were assessed using partial Pearson correlations, covaried for age, sex and race and ethnicity. Voxel-wise associations were also evaluated for amyloid and tau. The ability of visual contrast sensitivity to predict amyloid and tau positivity were assessed using forward conditional logistic regression and receiver operating curve analysis. All analyses first were done in the full sample and then in the non-demented at-risk individuals (subjective cognitive decline and mild cognitive impairment) only. Significant associations between visual contrast sensitivity and regional amyloid and tau deposition were observed across the full sample and within subjective cognitive decline and mild cognitive impairment only. Voxel-wise analysis demonstrated strong associations of visual contrast sensitivity with amyloid and tau, primarily in temporal, parietal and occipital brain regions. Finally, visual contrast sensitivity accurately predicted amyloid and tau positivity. Alterations in visual contrast sensitivity were related to cerebral deposition of amyloid and tau, suggesting that this measure may be a good biomarker for detecting Alzheimer's disease-related pathophysiology. Future studies in larger patient samples are needed, but these findings support the power of these measures of visual contrast sensitivity as a potential novel, inexpensive and easy-to-administer biomarker for Alzheimer's disease-related pathology in older adults at risk for cognitive decline.

15.
Neuroimage Clin ; 24: 101930, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31630026

RESUMEN

Recent evidence of short-term alterations in brain physiology associated with repeated exposure to moderate intensity subconcussive head acceleration events (HAEs), prompts the question whether these alterations represent an underlying neural injury. A retrospective analysis combining counts of experienced HAEs and longitudinal diffusion-weighted imaging explored whether greater exposure to incident mechanical forces was associated with traditional diffusion-based measures of neural injury-reduced fractional anisotropy (FA) and increased mean diffusivity (MD). Brains of high school athletes (N = 61) participating in American football exhibited greater spatial extents (or volumes) experiencing substantial changes (increases and decreases) in both FA and MD than brains of peers who do not participate in collision-based sports (N = 15). Further, the spatial extents of the football athlete brain exhibiting traditional diffusion-based markers of neural injury were found to be significantly correlated with the cumulative exposure to HAEs having peak translational acceleration exceeding 20 g. This finding demonstrates that subconcussive HAEs induce low-level neurotrauma, with prolonged exposure producing greater accumulation of neural damage. The duration and extent of recovery associated with periods in which athletes do not experience subconcussive HAEs now represents a priority for future study, such that appropriate participation and training schedules may be developed to minimize the risk of long-term neurological dysfunction.


Asunto(s)
Aceleración/efectos adversos , Atletas , Encéfalo/diagnóstico por imagen , Fútbol Americano/lesiones , Estudiantes , Sustancia Blanca/diagnóstico por imagen , Adolescente , Conmoción Encefálica/diagnóstico por imagen , Conmoción Encefálica/etiología , Imagen de Difusión por Resonancia Magnética/tendencias , Cabeza/diagnóstico por imagen , Humanos , Masculino , Instituciones Académicas/tendencias
16.
Alzheimers Dement (Amst) ; 11: 180-190, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30847382

RESUMEN

INTRODUCTION: Quantitative in vivo measurement of brain amyloid burden is important for both research and clinical purposes. However, the existence of multiple imaging tracers presents challenges to the interpretation of such measurements. This study presents a direct comparison of Pittsburgh compound B-based and florbetapir-based amyloid imaging in the same participants from two independent cohorts using a crossover design. METHODS: Pittsburgh compound B and florbetapir amyloid PET imaging data from three different cohorts were analyzed using previously established pipelines to obtain global amyloid burden measurements. These measurements were converted to the Centiloid scale to allow fair comparison between the two tracers. The mean and inter-individual variability of the two tracers were compared using multivariate linear models both cross-sectionally and longitudinally. RESULTS: Global amyloid burden measured using the two tracers were strongly correlated in both cohorts. However, higher variability was observed when florbetapir was used as the imaging tracer. The variability may be partially caused by white matter signal as partial volume correction reduces the variability and improves the correlations between the two tracers. Amyloid burden measured using both tracers was found to be in association with clinical and psychometric measurements. Longitudinal comparison of the two tracers was also performed in similar but separate cohorts whose baseline amyloid load was considered elevated (i.e., amyloid positive). No significant difference was detected in the average annualized rate of change measurements made with these two tracers. DISCUSSION: Although the amyloid burden measurements were quite similar using these two tracers as expected, difference was observable even after conversion into the Centiloid scale. Further investigation is warranted to identify optimal strategies to harmonize amyloid imaging data acquired using different tracers.

17.
Brain ; 142(4): 1063-1076, 2019 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-30753379

RESUMEN

Tauopathy is a hallmark pathology of Alzheimer's disease with a strong relationship with cognitive impairment. As such, understanding tau may be a key to clinical interventions. In vivo tauopathy has been measured using cerebrospinal fluid assays, but these do not provide information about where pathology is in the brain. The introduction of PET ligands that bind to paired helical filaments provides the ability to measure the amount and distribution of tau pathology. The heritability of the age of dementia onset tied to the specific mutations found in autosomal dominant Alzheimer's disease families provides an elegant model to study the spread of tau across the course of the disease as well as the cross-modal relationship between tau and other biomarkers. To better understand the pathobiology of Alzheimer's disease we measured levels of tau PET binding in individuals with dominantly inherited Alzheimer's disease using data from the Dominantly Inherited Alzheimer Network (DIAN). We examined cross-sectional measures of amyloid-ß, tau, glucose metabolism, and grey matter degeneration in 15 cognitively normal mutation non-carriers, 20 asymptomatic carriers, and 15 symptomatic mutation carriers. Linear models examined the association of pathology with group, estimated years to symptom onset, as well as cross-modal relationships. For comparison, tau PET was acquired on 17 older adults with sporadic, late onset Alzheimer disease. Tau PET binding was starkly elevated in symptomatic DIAN individuals throughout the cortex. The brain areas demonstrating elevated tau PET binding overlapped with those seen in sporadic Alzheimer's disease, but with a greater cortical involvement and greater levels of binding despite similar cognitive impairment. Tau PET binding was elevated in the temporal lobe, but the most prominent loci of pathology were in the precuneus and lateral parietal regions. Symptomatic mutation carriers also demonstrated elevated tau PET binding in the basal ganglia, consistent with prior work with amyloid-ß. The degree of tau tracer binding in symptomatic individuals was correlated to other biomarkers, particularly markers of neurodegeneration. In addition to the differences seen with tau, amyloid-ß was increased in both asymptomatic and symptomatic groups relative to non-carriers. Glucose metabolism showed decline primarily in the symptomatic group. MRI indicated structural degeneration in both asymptomatic and symptomatic cohorts. We demonstrate that tau PET binding is elevated in symptomatic individuals with dominantly inherited Alzheimer's disease. Tau PET uptake was tied to the onset of cognitive dysfunction, and there was a higher amount, and different regional pattern of binding compared to late onset, non-familial Alzheimer's disease.


Asunto(s)
Enfermedad de Alzheimer/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Tauopatías/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Péptidos beta-Amiloides/metabolismo , Biomarcadores/metabolismo , Encéfalo/metabolismo , Cognición/fisiología , Disfunción Cognitiva/metabolismo , Demencia/metabolismo , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Ovillos Neurofibrilares/metabolismo , Presenilina-1/genética , Proteínas tau/metabolismo
18.
Neurol Ther ; 7(2): 249-263, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29987534

RESUMEN

Dementia with Lewy bodies is one of the most common causes of dementia. It is not as common as Alzheimer's disease; the general public's awareness of the disease is poor in comparison. Its effects on caregivers and patients alike are not well known to the general population. There are currently no FDA-approved medications specifically for the treatment of DLB. Many of the medications that are approved for Alzheimer's disease are widely used in the treatment of DLB with varying degrees of success. Treatment of DLB is life long and requires a dedicated team of physicians and caregivers to minimize the degree of morbidity and mortality experienced by the patients suffering from the disease as it progresses.

19.
Stroke ; 49(2): 296-303, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-29284738

RESUMEN

BACKGROUND AND PURPOSE: The Veterans Health Administration has engaged in quality improvement to improve vascular risk factor control. We sought to examine blood pressure (<140/90 mm Hg), lipid (LDL [low-density lipoprotein] cholesterol <100 mg/dL), and glycemic control (hemoglobin A1c <9%), in the year post-hospitalization for acute ischemic stroke or acute myocardial infarction (AMI). METHODS: We identified patients who were hospitalized (fiscal year 2011) with ischemic stroke, AMI, congestive heart failure, transient ischemic attack, or pneumonia/chronic obstructive pulmonary disease. The primary analysis compared risk factor control after incident ischemic stroke versus AMI. Facilities were included if they cared for ≥25 ischemic stroke and ≥25 AMI patients. A generalized linear mixed model including patient- and facility-level covariates compared risk factor control across diagnoses. RESULTS: Forty thousand two hundred thirty patients were hospitalized (n=75 facilities): 2127 with incident ischemic stroke and 4169 with incident AMI. Fewer stroke patients achieved blood pressure control than AMI patients (64%; 95% confidence interval, 0.62-0.67 versus 77%; 95% confidence interval, 0.75-0.78; P<0.0001). After adjusting for patient and facility covariates, the odds of blood pressure control were still higher for AMI than ischemic stroke patients (odds ratio, 1.39; 95% confidence interval, 1.21-1.51). There were no statistical differences for AMI versus stroke patients in hyperlipidemia (P=0.534). Among patients with diabetes mellitus, the odds of glycemic control were lower for AMI than ischemic stroke patients (odds ratio, 0.72; 95% confidence interval, 0.54-0.96). CONCLUSIONS: Given that hypertension control is a cornerstone of stroke prevention, interventions to improve poststroke hypertension management are needed.


Asunto(s)
Isquemia Encefálica/etiología , Infarto del Miocardio/complicaciones , Accidente Cerebrovascular/etiología , Anciano , Anciano de 80 o más Años , Isquemia Encefálica/complicaciones , Femenino , Humanos , Hiperlipidemias/complicaciones , Hipertensión/complicaciones , Ataque Isquémico Transitorio/complicaciones , Masculino , Persona de Mediana Edad , Factores de Riesgo , Accidente Cerebrovascular/complicaciones
20.
Alzheimer Dis Assoc Disord ; 32(1): 35-42, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29140859

RESUMEN

INTRODUCTION: Few studies to date have explored patient and caregiver views on the clinical use of amyloid positron emission tomography (PET). METHODS: A 7-item questionnaire assessing patient and caregiver views (510 total respondents) toward amyloid PET imaging was advertised broadly through alz.org/trialmatch. RESULTS: We received 510 unique responses from 48 US states, 2 Canadian provinces, the Dominican Republic, and Greece. Both patients and caregivers indicated that they would want to receive amyloid imaging if offered the opportunity. Over 88% of respondents had a positive response (∼10% with neutral and 2% with negative responses) to whether amyloid PET should be offered routinely and be reimbursed. Such information was felt to be useful for long-term legal, financial, and health care planning. Respondents identifying with early age cognitive decline (younger than 65 y) were more likely to explore options for disability insurance (P=0.03). Responders from the Midwest were more likely to utilize information from amyloid imaging for legal planning (P=0.02), disability insurance (P=0.02), and life insurance (P=0.04) than other US regions. DISCUSSION: Patients and caregivers supported the use of amyloid PET imaging in clinical practice and felt that the information would provide significant benefits particularly in terms of future planning.


Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Péptidos beta-Amiloides/metabolismo , Cuidadores/psicología , Diagnóstico Precoz , Tomografía de Emisión de Positrones/métodos , Enfermedad de Alzheimer/psicología , Disfunción Cognitiva/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tomografía de Emisión de Positrones/economía , Encuestas y Cuestionarios
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