Journal of Alzheimer's Disease - Volume 55, issue 4

Authors: Quarmley, Megan | Moberg, Paul J. | Mechanic-Hamilton, Dawn | Kabadi, Sushila | Arnold, Steven E. | Wolk, David A. | Roalf, David R.

Article Type: Research Article

Abstract: Background: Measurements of olfaction may serve as useful biomarkers of incipient dementia. Here we examine the improvement in diagnostic accuracy of Alzheimer’s disease (AD) and mild cognitive impairment (MCI) when assessing both cognitive functioning and odor identification. Objective: To determine the utility of odor identification as a supplementary screening test in incipient AD. Methods: Sniffin’ Sticks Odor Identification Test (SS-OIT) and the Montreal Cognitive Assessment (MoCA) were administered in 262 AD, 174 MCI [150 amnestic (aMCI), and 24 non-amnestic (naMCI)], and 292 healthy older adults (HOA). Results: Odor identification scores were higher in …HOA relative to MCI or AD groups, and MCI outperformed AD. Odor identification scores were higher in aMCI single domain than aMCI multiple domain. Complementing MoCA scores with the SS-OIT significantly improved diagnostic accuracy of individuals with AD and MCI, including within MCI subgroups. Discussion: Odor identification is a useful supplementary screening tool that provides additional information relevant for clinical categorization of AD and MCI, including those who are at highest risk to convert to AD. Show more

Keywords: Alzheimer’s disease, mild cognitive impairment, Montreal Cognitive Assessment, odor identification, smell, Sniffin’ Sticks Olfactory Identification Test

DOI: 10.3233/JAD-160842

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1497-1507, 2017

Authors: Valdiglesias, Vanessa | Maseda, Ana | Lorenzo-López, Laura | Pásaro, Eduardo | Millán-Calenti, José C. | Laffon, Blanca

Article Type: Research Article

Abstract: Salivary chromogranin A (sCgA) is gaining attention as a biomarker of psychological stress. The objective of this work was to determine whether individualized music intervention and multisensory stimulation environment (MSSE) in a Snoezelen room produce changes in sCgA in severely demented older patients, and to assess the possible existence of differences in sCgA levels between the two types of interventions. Older adults with severe dementia (n  = 22) were randomly assigned to two intervention groups. They participated in MSSE or individualized music interventions in 30-min weekly sessions for 16 weeks. Levels of sCgA were evaluated before and after a session, or …30-min interval, at four different time points: before starting the trial, in the middle and end of the intervention period, and two months later. Comparison of sCgA values obtained after each session with those obtained before (or at the same hour in before trial and follow-up samplings) showed no significant differences either in the individualized music or in the MSSE group at any sampling time. Comparison between the two types of interventions, both before and after each session, in the four sampling times, did not produce any significant difference either. Furthermore, no significant correlation was obtained between agitation, anxiety, cognitive function, and dementia severity with sCgA levels. In conclusion, despite beneficial effects of both individualized music and MSSE interventions being previously reported on neuropsychiatric outcomes for older patients with dementia, sCgA seems to not be a good indicator of these benefits. Show more

Keywords: Chromogranin A, dementia, individualized music, multisensory stimulation, older adults, Snoezelen

DOI: 10.3233/JAD-160893

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1509-1517, 2017

Authors: Sennik, Simrin | Schweizer, Tom A. | Fischer, Corinne E. | Munoz, David G.

Article Type: Research Article

Abstract: Background: Neuropsychiatric symptoms are common manifestations of Alzheimer’s disease (AD). A number of studies have targeted psychosis, i.e., hallucinations and delusions in AD, but few have assessed agitation/aggression in AD. Objective: To investigate the risk factors and pathological substrates associated with presence [A(+)] and absence [A(–)] of agitation/aggression (A) in autopsy-confirmed AD. Methods: Data was collected from the UDS data as of 2015 on the NACC database. Patients were stratified as intermediate (IAD) or high (HAD) pathological load of AD. Clinical diagnoses were not considered; additional pathological diagnoses were treated as variables. Analysis of data …did not include a control group or corrections for multiple comparisons. Results: 1,716 patients met the eligibility criteria; 31.2% of the IAD and 47.8% of the HAD patients were A(+), indicating an association with severity of pathology (p  = 0.001). Risk factors for A(+) included: age at initial visit, age at death, years of education, smoking (in females), recent cardiac events (in males), and clinical history of traumatic brain injury (TBI) (in males). A history of hypertension was not related to A(+). In terms of comorbidity, clinical diagnosis of Lewy body dementia syndrome was associated with A(+) but the association was not confirmed when pathological diagnosis based on demonstration of Lewy bodies was used as the criterion. The additional presence of phosphorylated TDP-43, but not tau pathologies, was associated with A(+)HAD. Vascular lesions, including lacunes, large arterial infarcts, and severity of atherosclerosis were negatively associated with A(+). Associated symptoms included delusions, hallucinations, and depression, but not irritability, aberrant motor behavior, sleep and night time behavioral changes, or changes in appetite and eating habits. Conclusions: Smoking, TBI, and phosphorylated TDP-43 are associated with A(+)AD in specific groups, respectively. A(+) is directly associated with AD pathology load and inversely with vascular lesions. Show more

Keywords: Alzheimer’s disease, agitation, aggression, neuropathology, (p)-TDP-43, traumatic brain injury, vascular lesions, vascular risk factors

DOI: 10.3233/JAD-160780

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1519-1528, 2017

Authors: Cagnin, Annachiara | Fragiacomo, Federica | Camporese, Giulia | Turco, Matteo | Bussè, Cinzia | Ermani, Mario | Montagnese, Sara

Article Type: Research Article

Abstract: Background: Alterations of the sleep-wake cycle are common features of neurodegenerative dementia. Objectives: To study differences in sleep-wake profiles in dementia with Lewy bodies (DLB), Alzheimer’s disease (AD), and healthy controls. Methods: 30 DLB and 32 AD patients, and 33 healthy elderly participants were studied. Patients were evaluated for global cognitive impairment, extrapyramidal signs, fluctuations of attention, and behavioral disorders. A comprehensive sleep-wake profile was obtained including a set of questionnaires [Pittsburgh Sleep Quality Index (PSQI), REM Sleep Behavior Disorder Single-Question screen (RBD1Q), Epworth Sleepiness Scale (ESS)] and 12-day sleep diaries. Results: Patients …were matched for age, gender, and disease severity. DLB patients showed more severe daytime somnolence/dysfunction due to somnolence, and a higher proportion of RBD-like symptoms (70%) compared to AD and controls (p  < 0.001), regardless of the presence of psychoactive drug treatment. As for sleep timing, DLB patients had a greater number of daytime naps and longer night sleep, with the latter being associated with use of clonazepam. The severity of fluctuations was associated with the presence of RBD (Clinician Assessment of Fluctuation score = RBD+: 5.2±3.7; RBD-: 2.1±3.2, p  = 0.04). AD patients reported the best sleep-wake profile, while healthy controls declared the poorest sleep quality, although sleep timing and the quality of wakefulness were comparable between AD and controls. Discussion: RBD and daytime fluctuations of attention may coexist in DLB and even reciprocally potentiate each other. Self-reports of sleep quality may lead to an underestimation of sleep disturbances in AD, possibly influenced by anosognosia, compared to normal elderly individuals who complain mainly of insomnia. Show more

Keywords: Alzheimer’s disease, dementia with Lewy bodies, REM sleep behavior disorder, sleep disturbances

DOI: 10.3233/JAD-160385

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1529-1536, 2017

Authors: Waldron, Ann-Marie | wyffels, Leonie | Verhaeghe, Jeroen | Richardson, Jill C. | Schmidt, Mark | Stroobants, Sigrid | Langlois, Xavier | Staelens, Steven

Article Type: Research Article

Abstract: We aimed to monitor the timing of amyloid-β deposition in relation to changes in brain function using in vivo imaging with [18 F]-AV45 and [18 F]-FDG in a mouse model of Alzheimer’s disease. TASTPM transgenic mice and wild-type controls were scanned longitudinally with [18 F]-AV45 and [18 F]-FDG before (3 months of age) and at multiple time points after the onset of amyloid deposition (6, 9, 12, and 15 months of age). As expected with increasing amyloidosis, TASTPM mice demonstrated progressive age-dependent increases in [18 F]-AV45 uptake that were significantly higher than for WT from 9 months onwards and …correlated to ex vivo measures of amyloid burden. The metabolism of [18 F]-AV45 produces several brain penetrant radiometabolites and normalization to a reference region helps to negate this non-specific binding and improve the sensitivity of [18 F]-AV45. The observed trajectory of [18 F]-FDG alterations deviated from our proposed hypothesis of gradual decreases with worsening amyloidosis. While [18 F]-FDG uptake in TASTPM mice was significantly lower than that of WT at 9 months, reduced [18 F]-FDG was not associated with aging in TASTPM mice. Moreover, [18 F]-FDG uptake did not correlate to measures of ex vivo amyloid burden. Our findings suggest that while amyloid-β is sufficient to induce hypometabolism, these pathologies are not linked in a dose-dependent manner in TASTPM mice. Show more

Keywords: Alzheimer’s disease, [18F]-AV45, [18F]-FDG, longitudinal, small animal imaging, transgenic mice

DOI: 10.3233/JAD-160760

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1537-1548, 2017

Authors: Del Prete, Dolores | Suski, Jan M. | Oulès, Bénédicte | Debayle, Delphine | Gay, Anne Sophie | Lacas-Gervais, Sandra | Bussiere, Renaud | Bauer, Charlotte | Pinton, Paolo | Paterlini-Bréchot, Patrizia | Wieckowski, Mariusz R. | Checler, Frédéric | Chami, Mounia

Article Type: Research Article

Abstract: Alteration of mitochondria-associated membranes (MAMs) has been proposed to contribute to the pathogenesis of Alzheimer’s disease (AD). We studied herein the subcellular distribution, the processing, and the protein interactome of the amyloid-β protein precursor (AβPP) and its proteolytic products in MAMs. We reveal that AβPP and its catabolites are present in MAMs in cellular models overexpressing wild type AβPP or AβPP harboring the double Swedish or London familial AD mutations, and in brains of transgenic mice model of AD. Furthermore, we evidenced that both β- and γ -secretases are present and harbor AβPP processing activities in MAMs. Interestingly, cells overexpressing …APPswe show increased ER-mitochondria contact sites. We also document increased neutral lipid accumulation linked to Aβ production and reversed by inhibiting β- or γ -secretases. Using a proteomic approach, we show that AβPP and its catabolites interact with key proteins of MAMs controlling mitochondria and ER functions. These data highlight the role of AβPP processing and proteomic interactome in MAMs deregulation taking place in AD. Show more

Keywords: Alzheimer disease, amyloid-β protein precursor, lipids, mitochondria associated membranes, proteomic

DOI: 10.3233/JAD-160953

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1549-1570, 2017

Authors: Beheshti, Iman | Maikusa, Norihide | Matsuda, Hiroshi | Demirel, Hasan | Anbarjafari, Gholamreza | for the Japanese-Alzheimer’s Disease Neuroimaging Initiative

Article Type: Research Article

Abstract: Automatic computer-aided diagnosis (CAD) systems have been widely used in classification of patients who suffer from Alzheimer’s disease (AD). This paper presents an automatic CAD system based on histogram feature extraction from single-subject gray matter similarity-matrix for classifying the AD patients from healthy controls (HC) using structural magnetic resonance imaging (MRI) data. The proposed CAD system is composed of five stages. In the first stage, segmentation is employed to perform pre-processing on the MRI images, and segment into gray matter, white matter, and cerebrospinal fluid using the voxel-based morphometric toolbox procedure. In the second stage, gray matter MRI scans are …used to construct similarity-matrices. In the third stage, a novel statistical feature-generation process is proposed, utilizing the histogram of the individual similarity-matrix to represent statistical patterns of the respective similarity-matrices of different size and order into fixed-size feature-vectors. In the fourth stage, we propose to combine MRI measures with a neuropsychological test, the Functional Assessment Questionnaire (FAQ), to improve the classification accuracy. Finally, the classification is performed using a support vector machine and evaluated with the 10-fold cross-validation strategy. We evaluated the proposed method on 99 AD and 102 HC subjects from the J-ADNI. The proposed CAD system yields an 84.07% classification accuracy using MRI measures and 97.01% for combining MRI measures with FAQ scores, respectively. The experimental results indicate that the performance of the proposed system is competitive with respect to state-of-the-art techniques reported in the literature. Show more

Keywords: Alzheimer’s disease, Fisher criterion, histogram, individual gray matter, similarity-matrix

DOI: 10.3233/JAD-160850

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1571-1582, 2017

Authors: Fleiner, Tim | Leucht, Stefan | Förstl, Hans | Zijlstra, Wiebren | Haussermann, Peter

Article Type: Research Article

Abstract: Observational and interventional studies indicate a direct link between the patients’ physical activity and the extent of behavioral and psychological symptoms of dementia (BPSD). At present, there are no evidence-based recommendations for physical exercise in the acute dementia care settings. Hence, this systematic review investigates the effects of short-term exercise trials on BPSD. Trials with a length up to three months investigating the effects of structured exercise interventions on BPSD in acute dementia care settings were included. Five trials, referring to a total of N = 206 patients, met the inclusion criteria. The trial durations ranged from three up to twelve weeks. All trials conducted …three sessions per week of 30 to 45 minutes. Three trials reported significant reductions of BPSD and differences in comparison to the pre-test and control groups. Out of the three trials investigating the effects of exercise interventions on depressive symptoms, one reported significant reduction and two reported no differences in pre-post analysis. Exercise represents a potentially worthwhile approach for the treatment of patients suffering from BPSD. Given the scarcity of available studies, more randomized controlled short-term exercise trials in acute dementia care settings are needed to define appropriate exercise recommendations for clinicians treating these patients. Show more

Keywords: Behavioral symptoms, dementia, exercise, geriatric psychiatry, specialized hospitals

DOI: 10.3233/JAD-160683

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1583-1594, 2017

Authors: Slachevsky, Andrea | Guzmán-Martínez, Leonardo | Delgado, Carolina | Reyes, Pablo | Farías, Gonzalo A. | Muñoz-Neira, Carlos | Bravo, Eduardo | Farías, Mauricio | Flores, Patricia | Garrido, Cristian | Becker, James T. | López, Oscar L. | Maccioni, Ricardo B.

Article Type: Research Article

Abstract: Background: Intracellular neurofibrillary tangles are part of the core pathology of Alzheimer’s disease (AD), which are mainly composed of hyperphosphorylated tau protein. Objectives: The purpose of this study is to determine whether high molecular weight (HMW) or low molecular weight (LMW) tau protein levels, as well as the ratio HMW/LMW, present in platelets correlates with brain magnetic resonance imaging (MRI) structural changes in normal and cognitively impaired subjects. Methods: We examined 53 AD patients and 37 cognitively normal subjects recruited from two Memory Clinics at the Universidad de Chile. Tau levels in platelets were determined …by immunoreactivity and the MRI scans were analyzed using voxel-based morphometry in 41 AD patients. Results: The HMW/LMW tau ratio was statistically different between controls and AD patients, and no associations were noted between HMW or LMW tau and MRI structures. In a multivariate analysis controlled for age and education level, the HMW/LMW tau ratio was associated with reduced volume in the left medial and right anterior cingulate gyri, right cerebellum, right thalamus (pulvinar), left frontal cortex, and right parahippocampal region. Conclusions: This exploratory study showed that HMW/LMW tau ratio is significantly higher in AD patients than control subjects, and that it is associated with specific brain regions atrophy. Determination of peripheral markers of AD pathology can help understanding the pathophysiology of neurodegeneration in AD. Show more

Keywords: Alzheimer’s disease, medial temporal lobe atrophy, non-invasive biomarkers, tau variants

DOI: 10.3233/JAD-160652

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1595-1603, 2017

Authors: Dengler-Crish, Christine M. | Smith, Matthew A. | Wilson, Gina N.

Article Type: Research Article

Abstract: Reduced bone mineral density (BMD) and its clinical sequelae, osteoporosis, occur at a much greater rate in patients with Alzheimer’s disease (AD), often emerging early in the disease before significant cognitive decline is seen. Reduced BMD translates to increased bone fracture risk, decreased quality of life, and increased mortality for AD patients. However, the mechanism responsible for this observation is unclear. We hypothesize that bone loss is an additional component of an AD prodrome-changes that emerge prior to dementia and are mediated by dysfunction of the central serotonergic pathways. We characterized the skeletal phenotype of htau mice that express human forms …of the microtubule-associated protein tau that become pathologically hyperphosphorylated in AD. Using radiographic densitometry, we measured BMD in female and male htau mice from 2–6 months of age–time-points prior to the presence of significant tauopathy in the hippocampal/entorhinal regions characteristic of this model. We found a significantly reduced BMD phenotype in htau mice that was most pronounced in males. Using western blotting and immunofluorescence, we showed overall reduced tryptophan hydroxylase (TPH) protein in htau brainstem and a 70% reduction in TPH-positive cells in the dorsal raphe nucleus (DRN)–a pivotal structure in the regulation of the adult skeleton. Elevations of hyperphosphorylated tau (ptau) proteins were also measured in brainstem, and co-labeled immunofluorescence studies showed presence of ptau in TPH-positive cells of the DRN as early as 4 months of age in htau mice. Together, these findings demonstrate that reduced BMD occurs earlier than overt degeneration in a tau-based AD model and that pathological changes in tau phosphorylation occur in the serotonin-producing neurons of the brainstem raphe in these mice. This illuminates a need to define a mechanistic relationship between bone loss and serotonergic deficits in early AD. Show more

Keywords: Alzheimer’s disease, bone density, microtubule-associated protein, serotonin, tau proteins, tauopathies

DOI: 10.3233/JAD-160658

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1605-1619, 2017

Authors: Mariani, Elena | Chattat, Rabih | Vernooij-Dassen, Myrra | Koopmans, Raymond | Engels, Yvonne

Article Type: Research Article

Abstract: Background: Care planning nowadays is a key activity in the provision of services to nursing home residents. A care plan describes the residents’ needs and the actions to address them, providing both individualized and standardized interventions and should be updated as changes in the residents’ conditions occur. Objective: The aim of this review was to identify the core elements of the implementation of changes in nursing homes’ care plans, by providing an overview of the type of stakeholders involved, describing the implementation strategies used, and exploring how care plans changed. Methods: An integrative literature review was used …to evaluate intervention studies taking place in nursing homes. Data were collected from PubMed, CINHAL-EBSCO, and PsycINFO. English language articles published between 1995 and April 2015 were included. Data analysis followed the strategy of Knafl and Whittemore. Results: Twenty-six articles were included. The stakeholders involved were professionals, family caregivers, and patients. Only a few studies directly involved residents and family caregivers in the quality improvement process. The implementation strategies used were technology implementation, audit, training, feedback, and supervision. The majority of interventions changed the residents’ care plans in terms of developing a more standardized care documentation that primarily focuses on its quality. Only some interventions developed more tailored care plans that focus on individualized needs. Conclusion: Care plans generally failed in providing both standardized and personalized interventions. Efforts should be made to directly involve residents in care planning and provide professionals with efficient tools to report care goals and actions in care plans. Show more

Keywords: Care plan, elderly residents, implementation, nursing documentation, nursing homes, quality improvement, stakeholders

DOI: 10.3233/JAD-160559

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1621-1638, 2017

Authors: Pandya, Sneha | Kuceyeski, Amy | Raj, Ashish | for the Alzheimer’s Disease Neuroimaging Initiative

Article Type: Research Article

Abstract: Alzheimer’s disease (AD), one of the most common causes of dementia in adults, is a progressive neurodegenerative disorder exhibiting well-defined neuropathological hallmarks. It is known that disease pathology involves misfolded amyloid-β (Aβ) and tau proteins, and exhibits a relatively stereotyped progression over decades. The relationship between AD neuropathological hallmarks (Aβ, hypometabolism, and tau proteins) and imaging biomarkers (MRI, AV-45/FDG-PET) is not fully understood. In addition, biomarker pathologies are oftentimes discordant, wherein it may show varying levels of abnormality across brain regions. Evidence based on recent elucidation of trans-neuronal “prion-like” transmission and other available data already suggests that disease spread follows …the brain’s fiber connectivity network. Thereby, the brain’s connectome information can be used to predict the process of disease spread in AD. A recently established mathematical model of AD pathology spread using a connectome-based network diffusion model was successful in encapsulating neurodegenerative progression. Motivated by these network-based findings, the current study explores whether and how network connectivity mediates the interactions between various AD biomarkers. We hypothesized that the structural connectivity matrix will mediate the cross-sectional association between regional AD-associated hypometabolism and Aβ deposition. Given recent reports of inherent or lifetime activity of brain regions as strong predictors of Aβ deposition in patients, we also tested whether healthy metabolism exerts a network-mediated effect on Aβ deposition and hypometabolism in AD patients. We found that regional Aβ deposition is best predicted by a linear combination of both regional healthy local metabolism and connectome-mediated regional healthy metabolism. Show more

Keywords: Alzheimer’s disease, amyloid-β, AV-45-PET, biomarkers, cross-sectional, FDG-PET, hypometabolism, metabolism, structural connectivity

DOI: 10.3233/JAD-160090

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1639-1657, 2017

Authors: Sancesario, Giulia M. | Toniolo, Sofia | Chiasserini, Davide | Di Santo, Simona G. | Zegeer, Josh | Bernardi, Gaetano | for SIBioC-Study Group of Clinical Biochemistry of Biological Fluids other than Blood | Musicco, Massimo | for SINdem-ITALPLANED | Caltagirone, Carlo | Parnetti, Lucilla | Bernardini, Sergio

Article Type: Research Article

Abstract: Although the use of cerebrospinal fluid (CSF) amyloid β1-42 (Aβ42 ), tau (T-tau), and phosphorylated tau (p-tau181 ) gives added diagnostic and prognostic values, the diffusion is still limited in clinical practice and only a restricted number of patients receive an integrated clinico-biological diagnosis. By a survey, we aimed to do a “selfie” of the use and diffusion of CSF biomarkers of dementia in Italy, the standardization of pre-analytical procedures, the harmonization of ranges, and the participation to Quality Control programs. An online questionnaire was sent to the members of SIBioC and SINdem-ITALPLANED and to main neurological clinics all …over Italy. In Italy, 25 laboratories provide biomarkers analysis in addition to a network of 15 neighboring hospitals. In sum, 40 neurological centers require CSF analyses. 7/20 regions (35%) lack CSF laboratories. Standardization of pre-analytical procedures is present in 62.02% of the laboratories; only 56.00% of the laboratories participate in International Quality Control. There is no harmonization of cut-offs. In Italy, the use of CSF biomarkers is still limited in clinical practice. Standardization and harmonization of normal ranges are needed. To optimize and expand the use of CSF biomarkers, a cost–benefit analysis should be promoted by scientific societies and national health services. Show more

Keywords: Alzheimer’s disease diagnosis, cerebrospinal fluid, neurodegenerative biomarkers, survey

DOI: 10.3233/JAD-160975

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1659-1666, 2017

Authors: Hilt, Silvia | Tang, Tang | Walton, Jeffrey H. | Budamagunta, Madhu | Maezawa, Izumi | Kálai, Tamás | Hideg, Kálmán | Singh, Vikrant | Wulff, Heike | Gong, Qizhi | Jin, Lee-Way | Louie, Angelique | Voss, John C.

Article Type: Research Article

Abstract: Alzheimer’s disease (AD) is characterized by depositions of the amyloid-β (Aβ) peptide in the brain. The disease process develops over decades, with substantial neurological loss occurring before a clinical diagnosis of dementia can be rendered. It is therefore imperative to develop methods that permit early detection and monitoring of disease progression. In addition, the multifactorial pathogenesis of AD has identified several potential avenues for AD intervention. Thus, evaluation of therapeutic candidates over lengthy trial periods also demands a practical, noninvasive method for measuring Aβ in the brain. Magnetic resonance imaging (MRI) is the obvious choice for such measurements, but contrast enhancement for …Aβ has only been achieved using Gd(III)-based agents. There is great interest in gadolinium-free methods to image the brain. In this study, we provide the first demonstration that a nitroxide-based small-molecule produces MRI contrast in brain specimens with elevated levels of Aβ. The molecule is comprised of a  fluorene (a molecule with high affinity for Aβ) and a nitroxide spin label (a paramagnetic MRI contrast species). Labeling of brain specimens with the spin-labeled fluorene produces negative contrast in samples from AD model mice whereas no negative contrast is seen in specimens harvested from wild-type mice. Injection of spin-labeled fluorene into live mice resulted in good brain penetration, with the compound able to generate contrast 24-h post injection. These results provide a proof of concept method that can be used for early, noninvasive, gadolinium-free detection of amyloid plaques by MRI. Show more

Keywords: Alzheimer’s disease, amyloid-β, amyloid MRI contrast, magnetic resonance imaging, nitroxide spin label, spin-labeled fluorene

DOI: 10.3233/JAD-160279

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1667-1681, 2017

Authors: Wang, Ying | Zhou, Zhu | Tan, Hua | Zhu, Shenghua | Wang, Yiran | Sun, Yingxia | Li, Xin-Min | Wang, Jun-Feng

Article Type: Research Article

Abstract: Nitric oxide can attack thiol groups of cysteine residues in proteins and induce protein cysteine S-nitrosylation. Cholinergic and glutamatergic systems are dysregulated in Alzheimer’s disease. Vesicular acetylcholine transporter (VAChT) and vesicular glutamate transporter 1 (VGLUT1) are important in packaging acetylcholine and glutamate into vesicles, which is an important step for neurotransmission. Previously we found that VAChT and VGLUT1 can be nitrosylated and that S-nitrosylation of these transporters inhibits vesicular uptake of acetylcholine and glutamate. To understand the role of VAChT and VGLUT1 nitrosylation in the pathophysiological development of Alzheimer’s disease, we analyzed nitrosylation of VAChT and VGLUT1 in brain of …amyloid precursor protein (APP) and presenilin 1 (PS1) double transgenic mice, an animal model for Alzheimer’s disease. Using a Morris water maze test, we found that 9- and 12-month-old APP/PS1 mice showed memory deficit, compared to wild type mice. We further found that total protein nitrosylation was increased in frontal cortex and hippocampus of 9- and 12-month-old APP/PS1 mice. Although nitrosylation of VAChT and VGLUT1 was not changed in hippocampus of 9- and 12-month-old APP/PS1 mice, nitrosylation of VAChT and VGLUT1 was significantly increased in frontal cortex of APP/PS1 mice at these ages. We also found that nitrosylation of VAChT and VGLUT1 was increased in hippocampus (but not frontal cortex) of 3-month-old APP/PS1 mice. These findings suggest that nitrosylation of VAChT and VGLUT1 may be associated with dysfunctional acetylcholinergic and glutamatergic neurotransmission in Alzheimer’s disease. Show more

Keywords: Alzheimer’s disease, oxidative stress, protein nitrosylation, vesicular acetylcholine transporter, vesicular glutamate transporter

DOI: 10.3233/JAD-160700

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1683-1692, 2017

Article Type: Other

Citation: Journal of Alzheimer's Disease, vol. 55, no. 4, pp. 1693-1711, 2017