Elena Portacolone, Jodi Halpern, Jay Luxenberg, Krista L. Harrison, Kenneth E. Covinsky
Ethical Issues Raised by the Introduction of Artificial Companions to Older Adults with Cognitive Impairment: A Call for Interdisciplinary Collaborations
Abstract: Due to the high costs of providing long-term care to older adults with cognitive impairment, artificial companions are increasingly considered as a cost-efficient way to provide support. Artificial companions can comfort, entertain, and inform, and even induce a sense of being in a close relationship. Sensors and algorithms are increasingly leading to applications that exude a life-like feel. We focus on a case study of an artificial companion for people with cognitive impairment. This companion is an avatar on an electronic tablet that is displayed as a dog or a cat. Whereas artificial intelligence guides most artificial companions, this application also relies on technicians “behind” the on-screen avatar, who via surveillance, interact with users. This case is notable because it particularly illustrates the tension between the endless opportunities offered by technology and the ethical issues stemming from limited regulations. Reviewing the case through the lens of biomedical ethics, concerns of deception, monitoring and tracking, as well as informed consent and social isolation are raised by the introduction of this technology to users with cognitive impairment. We provide a detailed description of the case, review the main ethical issues and present two theoretical frameworks, the “human-driven technology” platform and the emancipatory gerontology framework, to inform the design of future applications.
Julie M. Robillard, Ian P. Goldman, Tony J. Prescott, François Michaud
Addressing the Ethics of Telepresence Applications Through End-User Engagement
Abstract: Portacolone et al.’s Ethics Review highlights the ethical challenges associated with the implementation of telepresence devices and applications in the context of aging and dementia. In this response, we review ethical considerations as they relate to specific modalities of telepresence, with an emphasis on the continuum of potential interaction agents, from known individuals to fully automated and intelligent interlocutors. We further discuss areas in need of empirical evidence to inform regulatory efforts in telepresence. We close with a call for meaningful end-user engagement at all stages of technology development.
Julie M. Robillard, Katarzyna Kabacińska
Realizing the Potential of Robotics for Aged Care Through Co-Creation
Abstract: Socially assistive robots have the potential to improve aged care by providing assistance through social interaction. While some evidence suggests a positive impact of social robots on measures of well-being, the adoption of robotic technology remains slow. One approach to improve technology adoption is involving all stakeholders in the process of technology development using co-creation methods. To capture relevant stakeholders’ priorities and perceptions on the ethics of robotic companions, we conducted an interactive co-creation workshop at the 2019 Geriatric Services Conference in Vancouver, BC. The participants were presented with different portrayals of robotic companions in popular culture and answered questions about perceptions, expectations, and ethical concerns about the implementation of robotic technology. Our results reveal that the most pressing ethical concerns with robotic technology, such as issues related to privacy, are critical potential barriers to technology adoption. We also found that most participants agree on the types of tasks that robots should help with, such as domestic chores, communication, and medication reminders. Activities that robots should not help with, according to the stakeholders, included bathing, toileting, and managing finances. The perspectives that were captured contribute to a preliminary outline of the areas of importance for geriatric care stakeholders in the process of ethical technology design and development.
Louise Marston, Gill Livingston, Anne Laybourne, Claudia Cooper (Handling Associate Editor: Teruyuki Matsuoka)
Becoming or Remaining Agitated: The Course of Agitation in People with Dementia Living in Care Homes. The English Longitudinal Managing Agitation and Raising Quality of Life (MARQUE) Study
Abstract: Care home residents with dementia often have accompanying agitation. We investigated agitation’s course at 5 time-points in 1,424 people with dementia over 16 months in 86 English care homes. We categorized baseline agitation symptoms on the Cohen-Mansfield Agitation Inventory (CMAI) into none (CMAI=29; 15%), subclinical (CMAI=30-45; 45%), or clinically-significant (CMAI>45; 40%). 88% of those with no agitation at baseline remained free of clinically-significant agitation at all follow-ups. Seventy percent of those exhibiting clinically-significant agitation at baseline had clinically-significant agitation at some follow-ups. Over a 16-month observation period, this study finds many care home residents with dementia never develop clinically significant agitation and interventions should be for treatment not prevention.
Yi Liu*, Huijie Bian*, Siyi Xu, Shu Shu, Junqiu Jia, Jian Chen, Xiang Cao, Xinyu Bao, Yue Gu, Shengnan Xia, Hui Yang, Linjie Yu, Yun Xu, Xiaolei Zhu *These authors contributed equally to this study.
Muscone Ameliorates Synaptic Dysfunction and Cognitive Deficits in APP/PS1 Mice
Abstract: Background: Dysfunction of synaptic plasticity leads to memory impairment in Alzheimer’s disease (AD). Muscone (Mus) has shown neuroprotective effects in cerebral ischemic models. However, little is known of Mus effects on AD. Objective: To investigate the effects of Mus on memory functions and synaptic plasticity in 6-month-old APP/PS1 double-transgenic mice and explore the potential mechanisms. Methods: Mus was intraperitoneally injected into APP/PS1 or wild-type mice, and cognitive function was assessed by Novel object recognition and Morris water maze tests. The levels of amyloid-β (Aβ) were evaluated by immunofluorescence staining and ELISA. Synaptic morphology and plasticity were evaluated by Golgi staining and long-term potentiation. Cell viability was examined by Cell Counting Kit-8 assay. The protein levels of histone deacetylase 2 (HDAC2) were accessed by western blotting and Immunofluorescence staining. The protein levels of microtubule associated protein 2 and synaptophysin were analyzed by immunofluorescence staining. The ubiquitination of HDAC2 was examined by co-immunoprecipitation. The interaction of Mus with HDAC2 was predicted by molecular docking analysis. Results: Mus treatment attenuated memory dysfunction, reduced Aβ level, and enhanced synaptic plasticity in APP/PS1 mice. In addition, Mus treatment decreased the level of HDAC2 in the hippocampus of APP/PS1 mice and Aβ1-42-induced primary neurons, which might be associated with increased HDAC2 ubiquitination induced by HDAC2 and Mus interaction. Conclusion: Mus protected against synaptic plasticity and memory impairment in APP/PS1 mice, and enhanced HDAC2 degradation via ubiquitination, indicating that Mus was a potential drug for AD treatment.
Hanna Lu, for the Open Access Series of Imaging Studies
Quantifying Age-Associated Cortical Complexity of Left Dorsolateral Prefrontal Cortex with Multiscale Measurements
Abstract: Background: Cortical complexity plays a central role in the diagnosis and prognosis of age-related diseases. However, little is known about the regional cortical complexity in the context of brain atrophy. Objective: We aimed to systematically examine the age-related changes of the cortical complexity of left dorsolateral prefrontal cortex (DLPFC) and its subregions. Methods: Two hundred and fourteen cognitively normal adults drawn from the Open Access Series of Imaging Studies (OASIS) were divided into four age groups: young, middle-aged, young-old, and old-old. Based on structural magnetic resonance imaging (sMRI) scans, the multiscale measures of cortical complexity included cortical thickness (mm), surface area (mm2), grey matter volume (mm3), density, gyrification index (GI), and fractal dimension (FD). Results: Advancing age was associated with reduced grey matter volume, pial surface area, density, and FD of left DLPFC, but correlated with increased cortical thickness and GI. Volumetric measures, cerebrospinal fluid volume in particular, showed better performance to discriminate young-old adults from old-old adults, while FD was more sensitive than the volumetric measures to discriminate young adults and middle-aged adults than the other measures. Conclusion: This is the first demonstration that chronological age has a pronounced and differential effect on the cortical complexity of left DLPFC. Our findings suggest that surface-based measures of cortical region, thickness, and gyrification in particular, could be considered as valuable imaging markers for the studies of aging brain and neurodegenerative diseases.
Chiara Cerami, Alessandra Dodich, Sandro Iannaccone, Giuseppe Magnani, Alessandra Marcone, Priscilla Guglielmi, Giovanna Vanoli, Stefano F. Cappa, Daniela Perani (Handling Associate Editor: Jordi A. Matias-Guiu)
Individual Brain Metabolic Signatures in Corticobasal Syndrome
Abstract: Background: Corticobasal syndrome (CBS) is the usual clinical presentation of patients with corticobasal degeneration pathology. Nevertheless, there are CBS individuals with postmortem neuropathology typical of Alzheimer’s disease (AD). Objective: In this study, we aim to detect FDG-PET metabolic signatures at the single-subject level in a CBS sample, also evaluated with cerebrospinal fluid (CSF) markers for AD pathology. Methods: 21 patients (68.9±6.4 years; MMSE score = 21.7±6.3) fulfilling current criteria for CBS were enrolled. All underwent a clinical-neuropsychological assessment and an instrumental evaluation for biomarkers of neurodegeneration, amyloid and tau pathology (i.e., FDG-PET imaging and CSF Aβ42 and tau levels) at close intervals. CBS subjects were classified according to the presence or absence of CSF markers of AD pathology (i.e., low Aβ42 and high phosphorylated tau levels). Optimized voxel-based SPM procedures provided FDG-PET metabolic patterns at the single-subject and group levels. Results: Eight CBS had an AD-like CSF profile (CBS-AD), while thirteen were negative (CBS-noAD). The two subgroups did not differ in demographic characteristics or global cognitive impairment. FDG-PET SPM t-maps identified different metabolic signatures. Namely, all CBS-AD patients showed the typical AD-like hypometabolic pattern involving posterior cingulate cortex, precuneus and temporo-parietal cortex, whereas CBS-noAD cases showed bilateral hypometabolism in fronto-insular cortex and basal ganglia that is typical of the frontotemporal lobar degeneration spectrum. Discussion: These results strongly suggest the inclusion of FDG-PET imaging in the diagnostic algorithm of individuals with CBS clinical phenotype in order to early identify functional metabolic signatures due to different neuropathological substrates, thus improving the diagnostic accuracy.
Zhenxu Xiao, Wanqing Wu, Qianhua Zhao, Xiaoniu Liang, Jianfeng Luo, Ding Ding
Association of Glaucoma and Cataract with Incident Dementia: A 5-Year Follow-Up in the Shanghai Aging Study
Abstract: Background: Growing evidence has shown the association between ophthalmic disorders and the risk of cognitive decline, but the conclusions were inconsistent. Objective: This study aimed to verify the hypothesis that glaucoma or cataract or their combination is associated with incident dementia in Chinese older adults. Methods: We followed up 1,659 non-demented community residents aged ≥60 years for an average of 5.2 years in the Shanghai Aging Study. Histories of glaucoma and cataract were collected based on self-report and medical record confirmation. Consensus diagnoses of incident dementia and Alzheimer's disease (AD) were made based on neurological and neuropsychological assessments. Results: During the follow-up, 168 cases (10.1%) of incident dementia and 124 cases (7.5%) of incident AD were identified. Participants with glaucoma at baseline had a significant risk of incident dementia (hazard ratio [HR]=2.38, 95% confidence interval [CI] 1.08-5.23) and incident AD (HR=2.77, 95% CI 1.17-6.56) after adjusting for confounders. There was no association between cataract and incident dementia (HR=1.23, 95% CI 0.85-1.79) or AD (HR=1.14, 95% CI 0.73-1.77). Those who had both glaucoma and cataract were more likely to develop dementia (HR=3.08, 95% CI 1.29-7.37) and AD (HR=3.72, 95% CI 1.52-9.14), compared to those without ophthalmic conditions. Conclusion: Glaucoma is an independent risk factor of incident dementia and AD. The comorbidity of glaucoma and cataract may significantly increase the risk of dementia and AD.
Christopher R. Beam, Cody Kaneshiro, Jung Yun Jang, Chandra A. Reynolds, Nancy L. Pedersen, Margaret Gatz (Handling Associate Editor: Laura Zahodne)
A Twin Study of Sex Differences in Genetic Risk for All Dementia, Alzheimer’s Disease (AD), and Non-AD Dementia
Abstract: Background: While sex differences in incidence of Alzheimer’s disease (AD) and potential explanations have received considerable attention, less attention has been paid to possible sex differences in genetic risk for AD. Objective: We examined sex differences in genetic and environmental influences on disease risk and age at onset for All Dementia, AD Only, and Non-AD Dementia. Methods: Twin pairs were drawn from the Swedish Twin Registry. All Dementia analysis included 9,467 pairs; AD only, 8,696 pairs; and non-AD dementia, 8,195 pairs. APOE analyses included 1,923 individual twins with measured ε4 alleles. Dementia diagnoses were based on clinical workup and national health registry linkage. Results: Although within-pair correlations for All Dementia and AD Only were higher for women than for men, sex differences did not statistically differ for genetic or environmental etiology of All Dementia, AD Only, and Non-AD dementia. Similar results were observed when looking at specific genetic effects (APOE ε4). Co-twin control analyses indicated that among twin pairs discordant for dementia, female twins without dementia had approximately 40% greater risk of developing dementia, compared with their male counterparts, in the 2-5 years following the first twin’s diagnosis. Conclusion: For All Dementia, AD Only, and Non-AD Dementia, genetic influences could be equated across sex. Co-twin analyses, however, suggest greater risk to female than to male co-twins of dementia cases even though sex differences in either genetic or shared environmental influences on the risk of dementia could not be differentiated.
Mario Hernandes-Alejandro, Sarita Montaño, Charles R. Harrington, Claude M. Wischik, Andrés Salas-Casas, Pedro Cortes-Reynosa, Eduardo Pérez Salazar, Javier Cazares-Apatiga, Ricardo Apatiga-Perez, Miguel Ángel Ontiveros Torres, George Perry, Mar Pacheco-Herrero, José Luna-Muñoz (Handling Editor: Jesús Ávila)
Analysis of the Relationship Between Metalloprotease-9 and Tau Protein in Alzheimer’s Disease
Abstract: Background: Neurofibrillary tangles (NFTs) and amyloid plaques are the neuropathological hallmarks in brains with Alzheimer’s disease (AD). Post-translational modifications of tau, such as phosphorylation and truncation, have been proposed as initiators in the assembly of the abnormal paired helical filaments that constitute the NFTs. Neurons and NFTs are sites of matrix metalloproteinases (MMPs). Objective: The aim of this study was to analyze the relationship of MMP-9 and tau protein in brain samples with AD. Methods: This study was performed on brain tissue samples from patients with early, moderate, and late AD. MMPs and tau levels were analyzed by western blot and gelatin-substrate zymography. Immunofluorescence techniques and confocal microscopy were used to analyze the presence of both proteins in NFTs. Further, molecular dynamics simulations (MDS) and protein-protein docking were conducted to predict interaction between MMP-9 and tau protein. Results: MMP-9 expression was greatest in moderate and late AD, whereas MMP-2 expression was only increased in late-stage AD. Interestingly, confocal microscopy revealed NFTs in which there was co-localization of MMP-9 and tau protein. MDS and protein-protein docking predictions indicate that a high-affinity complex can be formed between MMP-9 and full-length tau protein. Conclusion: These observations provide preliminary evidence of an interaction between these two proteins. Post-translational modifications of tau protein, such as C-terminal truncation or phosphorylation of amino acid residues in the MMP-9 recognition site and conformational changes in the protein, such as folding of the N-terminal sequence over the three-repeat domain, could preclude the interaction between MMP-9 and tau protein during stages of NFT development.
Amir Fazlollahi, Parnesh Raniga, Pierrick Bourgeat, Paul Yates, Ashley I. Bush, Olivier Salvado*, Scott Ayton* *These authors contributed equally to this work.
Restricted Effect of Cerebral Microbleeds on Regional Magnetic Susceptibility
Abstract: Background: Cortical iron accumulation has been reported as a pathological feature of Alzheimer’s disease (AD). The cause of cortical iron elevation in AD is unknown but may be contributed by hemosiderin deposits in cerebral microbleeds that frequently occur in this disease. Objective: To investigate the impact of cerebral microbleeds (which are more frequent in AD) on the magnetic susceptibility of the surrounding brain tissue. Methods: 32 MRI scans from the Australian Imaging, Biomarker and Lifestyle (AIBL) study were found to have cerebral microbleeds by manual assessment of susceptibility weighted images. Quantitative susceptibility mapping (QSM; an MRI technique that is sensitive to iron) was used to estimate iron content in the tissue surrounding the microbleed in four concentric radii. Furthermore, the mirror regions on the contralateral hemisphere were also demarcated. A simulation analysis was conducted to investigate the effect of QSM imaging on cerebral microbleeds with varying sizes. Results: 77 microbleeds were identified from the available scans. The immediate proximal region to the cerebral microbleeds had enhanced tissue susceptibility (~0.02 PPM), but importantly, this did not extend beyond one voxel radius. This finding with in vivo data was also replicated in a simulation study. However, the presence of microbleeds could lead to over-estimation of tissue QSM in unsupervised quantification, therefore processing methods to avoid this artefact without the need for their manual identification are proposed. Conclusion: The local changes in susceptibility due to microbleeds outside the focal lesion are restricted to 1 voxel and may be explained by partial voluming artefacts caused by limited imaging resolution. The susceptibly change induced by the microbleed is a relatively small proportion of tissue and could not account for regional iron changes observed in AD cortex.
Douglas Barthold, Geoffrey Joyce, Patricia Ferido, Emmanuel F. Drabo, Zachary A. Marcum, Shelly L. Gray, Julie Zissimopoulos (Handling Associate Editor: Igor Akushevich)
Pharmaceutical Treatment for Alzheimer’s Disease and Related Dementias: Utilization and Disparities
Abstract: Background: Four prescription drugs (donepezil, galantamine, memantine, and rivastigmine) are approved by the US FDA to treat symptoms of Alzheimer’s disease (AD). Even modest effectiveness could potentially reduce the population-level burden of AD and related dementias (ADRD), especially for women and racial/ethnic minorities who have higher incidence of ADRD. Objective: Describe the prevalence of antidementia drug use and timing of initiation relative to ADRD diagnosis among a nationally representative group of older Americans, and if there are disparities in prevalence and timing by sex and race/ethnicity. Methods: Descriptive analyses and logistic regressions of Medicare claims (2008-2016) for beneficiaries who had an ADRD or dementia-related symptom diagnosis, or use of an FDA approved drug for AD. We investigate prevalence of use and timing of treatment initiation relative to ADRD diagnosis across time and beneficiary characteristics (age, sex, race/ethnicity, socioeconomic status, comorbidities). Results: Among persons diagnosed with ADRD or related symptoms, 33.3% used an approved drug over the study period. Odds of use was higher among Whites than non-Whites. Among ADRD drug users, 40% initiated use within 6 months of the initial ADRD or related symptoms diagnosis, and 16% initiated prior to a diagnosis. We observed disparities by race/ethnicity: 28% of Asians, 24% of Hispanics, 16% of Blacks, and 15% of Whites initiated prior to diagnosis. Conclusions: The use of antidementia drugs is relatively low and varies widely by race/ethnicity. Heterogeneity in timing of initiation and use may affect health and cost outcomes, but these effects merit further study.
Sarah Prieto, Kate E. Valerio, Jena N. Moody, Scott M. Hayes, Jasmeet P. Hayes, for the Alzheimer’s Disease Neuroimaging Initiative (Handling Associate Editor: Ralph Buchert)
Genetic Risk for Alzheimer’s Disease Moderates the Association Between Medial Temporal Lobe Volume and Episodic Memory Performance Among Older Adults
Abstract: Background: A complex set of interactions between biological, genetic, and environmental factors likely underlies the development of Alzheimer’s disease (AD). Identifying which of these factors is most associated with AD is important for early diagnosis and treatment. Objective: We sought to examine genetic risk and structural brain volume on episodic memory in a sample of older adults ranging from cognitively normal to those diagnosed with AD. Methods: 686 adults (55-91 years old) completed a 3T MRI scan, baseline cognitive assessments, and biospecimen collection through the Alzheimer’s Disease Neuroimaging Initiative. Hierarchical linear regression analyses examined main and interaction effects of medial temporal lobe (MTL) volume and polygenic hazard score (PHS), indicating genetic risk for AD, on a validated episodic memory composite score. Results: Genetic risk moderated the relationship between MTL volume and memory, such that individuals with high PHS and lower hippocampal and entorhinal volume had lower memory composite scores [ΔF (1,677) = 4.057, p = 0.044, ΔR2 = 0.002]. Further analyses showed this effect was driven by the left hippocampus [ΔF(1,677) = 5.256, p = 0.022, ΔR2 = 0.003] and right entorhinal cortex [ΔF (1,677) = 6.078, p = 0.014, ΔR2 = 0.003]. Conclusions: Among those with high genetic risk for AD, lower volume was associated with poorer memory. Results suggest that the interaction between AD genetic risk and MTL volume increases the likelihood for memory impairment among older adults. Results from this study suggest that genetic risk and brain volume should be considered key factors in tracking cognitive decline.
Cameron Isaacs-Trepanier, Mahwesh Saleem, Nathan Herrmann, Walter Swardfager, Paul I. Oh, Benjamin I. Goldstein, Jane Mitchell, Kim S. Sugamori, Krista L. Lanctôt
Endostatin as a Mediator Between Endothelial Function and Cognitive Performance in Those at Risk for Vascular Cognitive Impairment
Abstract: Background: Patients with coronary artery disease have an increased risk for developing vascular cognitive impairment. Endothelial function is often diminished and has been associated with lower cognitive performance in these patients. The link between endothelial function and cognition in coronary artery disease is not fully understood. Angiogenesis may play a role in mediating the association between endothelial function and cognition since angiogenic processes rely heavily on the endothelium. Objective: The aim of this study was to determine if markers of angiogenesis mediate the relationship between endothelial function and cognition in coronary artery disease patients. Methods: In 50 participants with coronary artery disease, endothelial function was assessed using peripheral arterial tonometry. Vascular endothelial growth factor (pro-angiogenic) and endostatin (anti-angiogenic) were measured in peripheral serum samples. Cognition was assessed using the Montreal Cognitive Assessment. A mediation analysis, using a bias corrected inferential bootstrapping method with 10,000 permutations, was used to determine if vascular endothelial growth factor or endostatin mediated an association between peripheral arterial tonometry measures and cognitive performance on the Montreal Cognitive Assessment. Results: Endostatin, but not vascular endothelial function, mediated a relationship between endothelial function and cognitive performance when controlling for total years of education, body mass index, coronary artery bypass graft, stent, diabetes, and diuretic use. This analysis was also significant when delayed recall was substituted for the overall score on the Montreal Cognitive Assessment. Conclusion: These results suggest that endostatin mediates an association between endothelial function and cognitive performance in coronary artery disease.
Ryan M. Wood, Zacnite Garcia, Nathan Daniels, Shannon M. Landon, Saima Humayun, Hyoung-gon Lee, Lindsey J. Macpherson
Selective Peripheral Taste Dysfunction in APP/PS1 Mutant Transgenic Mice
Abstract: Background: Previous studies indicate that taste dysfunction occurs early in the development of Alzheimer’s disease. It is debatable whether the deficit in taste is due primarily to peripheral sensory mechanisms or to central processing, or a combination of the two. Objective: The aim of our current study is to combine behavior and histological data in APP/PS1 transgenic mice to determine whether APP/PS1 transgenic mice show deficits in unconditioned taste preference and avoidance behaviors and whether taste impairments are due to defects in the peripheral taste system and/or problems with central processing of taste information. Methods: The APP/PS1 transgenic mutant mice were used as a model of Alzheimer’s disease. We employed a brief-access gustometer test to assess immediate orosensory taste responses of APP/PS1 mice. We used immunohistochemistry to examine tongue, gustatory ganglion, and brain tissues to determine a cytological basis for behavioral deficits. Results: There is a significant, selective reduction of bitter taste sensitivity in APP/PS1 mice. These mice also have a loss of TRPM5-expressing taste receptor cells in the circumvallate papillae of the tongue. While we observed no overt loss of neuron cell bodies within the primary gustatory sensory neurons, degeneration of the neurons’ peripheral axons innervating the taste bud may play a role in the observed loss of TRPM5-expressing taste receptor cells. Conclusion: This data supports a potential role for peripheral taste dysfunction in AD through the selective loss of taste receptor cells. Further study is necessary to delineate the mechanisms and pathological significance of this deficit in AD.
Zizhen Si, Yuchun Kang, Xidi Wang, Xue Wang, Changhui Sun, Yuanxin Li, Jiakun Xu, Jiajia Wu, Zhujun Zhang, Ling Li, Yahui Peng, Jihong Li, Chongran Sun, Yang Hui, Xu Gao (Handling Associate Editor: Wolff Kirsch)
Heme Oxygenase 1 Inhibits Adult Neural Stem Cells Proliferation and Survival via Modulation of Wnt/β-Catenin Signaling
Abstract: Background: Adult hippocampal neurogenesis is critical for renewing hippocampal neural circuits and maintaining hippocampal cognitive function and is closely associated with age-related neurodegenerative diseases. Heme oxygenase 1 (HO-1) is a stress protein that catalyzes the degradation of heme into free iron, biliverdin, and carbon monoxide. Elevated HO-1 level constitutes a pathological feature of Alzheimer’s disease, Parkinson’s disease, and many other age-related neurodegenerative diseases. Objective: Here we research the precise role of HO-1 in adult hippocampal neurogenesis. Methods: To explore the effect of HO-1 overexpression on adult neural stem cells (aNSCs) and elucidate its mechanisms, Tg(HO-1) was constructed. The transgenic mice and aNSCs were subjected to neurosphereing assay, clonal analysis, and BrdU labelling to detect the proliferation and self-renewal ability. LiCl, MG132, CHX, and IGF-1 treatment were used to research the signaling pathways which regulated by HO-1. Results: HO-1 overexpression decreased proliferation ability and induced apoptosis of aNSCs in subgranular zoon (SGZ) in vivo and in vitro. Furthermore, HO-1 overexpression inactivated canonical WNT/β-catenin pathway. Re-activate canonical WNT/β-catenin pathway rescued aNSCs proliferation and survival upon HO-1 overexpression. More importantly, phosphorylation of AKTS473 and GSK3βS9 was found to be significantly decreased in HO-1 overexpressed aNSCs. Re-activation of AKT signaling proved that HO-1 inhibited Wnt/β-catenin signaling pathway via AKT/GSK3β signaling pathway. Conclusion: These results demonstrated a critical role of HO-1 in regulating aNSCs survival and proliferation by inhibiting Wnt/β-catenin pathway through repression of AKT/GSK3β, which provide a novel insight into the role of HO-1 in Alzheimer’s disease pathogenesis.
Ane Iriondo, Maite García-Sebastian, Arantzazu Arrospide, Maria Arriba, Sara Aurtenetxe, Myriam Barandiaran, Montserrat Clerigue, Mirian Ecay-Torres, Ainara Estanga, Alazne Gabilondo, Andrea Izagirre, Jon Saldias, Mikel Tainta, Jorge Villanua, Kaj Blennow, Henrik Zetterberg, Javier Mar, Beatriz Abad-García, Irundika H.K. Dias, Felix M. Goñi, Pablo Martínez-Lage
Cerebrospinal Fluid 7-Ketocholesterol Level Is Associated with Amyloid-β42 and White Matter Microstructure in Cognitively Healthy Adults
Abstract: Background: Abnormal cholesterol metabolism changes the neuronal membrane and may promote amyloidogenesis. Oxysterols in cerebrospinal fluid (CSF) are related to Alzheimer’s disease (AD) biomarkers in mild cognitive impairment and dementia. Cholesterol turnover is important for axonal and white matter (WM) microstructure maintenance. Objective: We aim to demonstrate that the association of oxysterols, AD biomarkers, and WM microstructure occurs early in asymptomatic individuals. Methods: We studied the association of inter-individual variability of CSF 24-hydroxycholesterol (24-OHC), 27-hydroxycholesterol (27-OHC), 7-ketocholesterol (7-KC), 7β-hydroxycholesterol (7β-OHC), amyloid-β42 (Aβ42), total-tau (t-tau), phosphorylated-tau (p-tau), neurofilament (NfL), and WM microstructure using diffusion tensor imaging, generalized linear models and moderation/mediation analyses in 153 healthy adults. Results: Higher 7-KC levels were related to lower Aβ42, indicative of greater AD pathology (p = 0.041). Higher 7-KC levels were related to lower fractional anisotropy (FA) and higher mean (MD), axial (AxD), and radial (RD) diffusivity. 7-KC modulated the association between AxD and NfL in the corpus callosum splenium (B = 39.39, p = 0.017), genu (B = 68.64, p = 0.000), and fornix (B = 10.97, p = 0.000). Lower Aβ42 levels were associated to lower FA and higher MD, AxD, and RD in the fornix, corpus callosum, inferior longitudinal fasciculus, and hippocampus. The association between AxD and Aβ42 was moderated by 7K-C (p= 0.048). Conclusion: This study adds clinical evidence to support the role of 7K-C on axonal integrity and the involvement of cholesterol metabolism in the Aβ42 generation process.
Ling-Li Lv*, Bo Liu*, Jing Liu, Li-Sheng Li, Feng Jin, Yun-Yan Xu, Qin Wu, Jie Liu, Jing-Shan Shi *These authors contributed equally to this work.
Dendrobium nobile Lindl Alkaloids Ameliorate Cognitive Dysfunction in Senescence Accelerated SAMP8 Mice by Decreasing Amyloid-β Aggregation and Enhancing Autophagy Activity
Abstract: Background: Dendrobium nobile is a well-known traditional Chinese herbal medicine used for age-related diseases. Dendrobium nobile Lindl alkaloid (DNLA) is the active ingredient to improve learning and memory deficits in laboratory animals. Objective: The aim of the present study was to examine the anti-aging effects of long-term administration of DNLA and metformin during the aging process in senescence-accelerated mouse-prone 8 (SAMP8) mice. Methods: SAMP8 mice were orally given DNLA (20 and 40 mg/kg) or metformin (80 mg/kg) starting at 6 months of age until 12 months of age. Age-matched SAMR1 mice were used as controls. DNLA and metformin treatments ameliorated behavioral deficits of 12-month-old SAMP8 mice, as determined by Rotarod, Y-maze, and Open-field tests. Results: DNLA and metformin treatments prevented brain atrophy and improved morphological changes in the hippocampus and cortex, as evidenced by Nissl and H&E staining for neuron damage and loss, and by SA-β-gal staining for aging cells. DNLA and metformin treatments decreased amyloid-β1-42, AβPP, PS1, and BACE1, while increasing IDE and neprilysin for Aβ clearance. Furthermore, DNLA and metformin enhanced autophagy activity by increasing LC3-II, Beclin1, and Klotho, and by decreasing p62 in the hippocampus and cortex. Conclusion: The beneficial effects of DNLA were comparable to metformin in protecting against aging-related cognitive deficits, neuron aging, damage, and loss in SAMP8 mice. The mechanisms could be attributed to increased Aβ clearance, activation of autophagy activity, and upregulation of Klotho.
Salka S. Staekenborg, Naomi Kelly, Jacqueline Schuur, Pieter Koster, Erik Scherder, Caroline E.M. Tielkes, Philip Scheltens, Jules J. Claus
Education as Proxy for Cognitive Reserve in a Large Elderly Memory Clinic: ‘Window of Benefit’
Abstract: Background: The role of cognitive reserve (CR) to explain individual differences in cognitive functioning is unclear in memory clinic patients. Objective: To examine the cross-sectional effect of CR on cognition in relation to levels of neurodegeneration in a large elderly single-center memory clinic population. Methods: We included patients with subjective cognitive impairment (SCI, n=481), mild cognitive impairment (MCI, n=628) or Alzheimer’s disease (AD, n=1,099). Education was used as proxy for CR and visually rated medial temporal lobe atrophy (MTA) on CT was used as parameter of neurodegeneration. Relations between CR, cognition, and MTA were analyzed with multiple linear regression adjusted for age, sex, and cerebral atrophy. In addition, we examined if education affects the relation between MTA and cognition using an interaction variable. Results: Education was significantly related to all measures of cognition including subtests with an explained variance of education as a determinant of cognition of 11%. More highly educated patients had more advanced levels of MTA at the same level of cognition. All these results were stronger or only present in demented compared to non-demented patients but appeared no longer significant in those with lowest overall cognition. The interaction effect was significant indicating that with more advanced MTA, less cognitive decline was shown in higher educated patients. Conclusion: Education is a very strong determinant of cognition in an elderly memory clinic population. The positive effect of education was stronger in demented than in non-demented patients but disappeared in those with the lowest cognitive scores indicating a “window of CR benefit”.
Caterina Motta, Annamaria Finardi, Sofia Toniolo, Francesco Di Lorenzo, Eugenia Scaricamazza, Stefano Loizzo, Nicola Biagio Mercuri, Roberto Furlan, Giacomo Koch, Alessandro Martorana (Handling Associate Editor: Tommaso Schirinzi)
Protective Role of Cerebrospinal Fluid Inflammatory Cytokines in Patients with Amnestic Mild Cognitive Impairment and Early Alzheimer’s Disease Carrying Apolipoprotein E4 Genotype
Abstract: Background: Neuroinflammatory cytokines can play a pivotal role in Alzheimer’s disease (AD) contributing to the evolution of degenerative processes. Objective: We aimed at evaluating the levels of cerebrospinal fluid (CSF) inflammatory cytokines, chemokines, and growth factors in subjects with diagnosis of amnestic mild cognitive impairment and mild AD. Methods: We evaluated CSF contents of inflammatory cytokines in 66 patients divided according to the NIA-AA research framework and the APOE genotype. CSF of a group of cognitively unimpaired individuals (n=23) was evaluated as control. All patients were evaluated for 24 months using Mini-Mental State Examination (MMSE). Results: We found significant increased levels of IL-4, IL-6, IL-8, and G-CSF in the CSF of A+/T- APOE4 carriers, respect to A+/T- patients homozygous for APOE3, respect to A+/T+ patients, regardless the APOE status, and respect to controls. Over a period of 24 months, A+/T- APOE4 carriers, with increased levels of cytokines, showed a preserved cognitive evaluation when compared to the other subgroups of patients (delta MMSE at 24 months respect to baseline: 0.100.35; p<0.05). Conclusion: Our data suggest that during early phases of AD, in APOE4 carriers, Aβ pathology likely induces a specific cytokines pattern synthesis associated to cognitive preservation. These data highlight the different role that neuroinflammation can play in AD pathology based on the presence of specific CSF biomarkers and on the APOE status.
Mackenzie E. Fowler, Kristen L. Triebel, Gary R. Cutter, Lon S. Schneider, Richard E. Kennedy for the Alzheimer’s Disease Neuroimaging Initiative
Progression of Alzheimer’s Disease by Self-Reported Cancer History in the Alzheimer’s Disease Neuroimaging Initiative
Abstract: Background: Cross-sectional studies suggest self-reported cancer history is associated with decreased risk of Alzheimer’s disease (AD). However, little is known about how self-reported cancer affects longitudinal AD progression, the primary outcome in clinical trials and observational studies. Objective: To determine self-reported cancer history’s effect on longitudinal AD progression in an observational study. Methods: We utilized data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to evaluate progression to AD by self-reported all-cancer, breast, prostate, colorectal, or non-melanoma skin cancer history. Linear mixed effects models were used to examine baseline differences and rates of progression on the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) by self-reported cancer history. Age at AD onset was examined using consensus clinical diagnoses with Cox proportional hazards regression. Results: Among 1,271 participants, models revealed no significant differences in progression over time but did reveal significantly lower baseline ADAS-Cog score, indicating better cognition at a given age in those with self-reported cancer history. Cox models indicated those with self-reported cancer history had significantly later age of AD onset (HR: 0.67, 95% CI: 0.53-0.85) after adjustment for covariates. Conclusion: Participants with self-reported cancer history entered ADNI with better cognition and later age of AD onset, but progressed similarly to participants without such history, indicating differences in AD between those with and without self-reported cancer history emerge early in the disease course. Such differences in longitudinal progression by self-reported cancer history could affect AD trials and observational studies, given the current focus on early disease course. Further investigation is warranted with detailed longitudinal assessment of cancer and AD.
Keitaro Makino, Sangyoon Lee, Seongryu Bae, Yohei Shinkai, Ippei Chiba, Hiroyuki Shimada
Combined Effects of Pain Interference and Depressive Symptoms on Dementia Incidence: A 36-Month Follow-Up Study
Abstract: Background: Both pain interference and depressive symptoms have certain effects on dementia, and these are reciprocally related. However, comorbid effects of pain interference and depressive symptoms on dementia have not been examined in detail. Objective: This longitudinal study aimed to examine the combined effects of pain interference and depressive symptoms on the incidence of dementia in community-dwelling elderly individuals. Methods: This prospective cohort study with a 36-month follow-up period included 4,326 community-dwelling elderly individuals without dementia at baseline. Pain interference and depressive symptoms were assessed for every participant at baseline. We collected medical records in the Japanese public health insurance system to identify the incidence of dementia for 36 months. Results: The incidence rates of dementia during the follow-up period in the control, pain-interference, depressive-symptoms, and comorbid group were 3.2%, 6.2%, 7.9%, and 11.3%, respectively. A Cox regression analysis showed that the hazard ratios for the incidence of dementia were 1.85 (95% CI: 1.13-3.03) in the pain interference group, 1.87 (95% CI: 1.27-2.76) in the depressive symptoms group, and 2.20 (95% CI: 1.26-3.84) in the comorbid group, after adjusting for covariates. Conclusion: The coexistence of pain interference and depressive symptoms had a greater effect on the incidence of dementia than either condition alone in community-dwelling elderly individuals. Pain interference and depressive symptoms are known as common comorbid conditions and often form a negative cycle that accelerates the worsening of the individual symptoms of both. Thus, the comorbidity of these conditions may require monitoring for the prevention of dementia.
Yating He, Haihua Zhang, Tao Wang, Zhifa Han, Qing-bin Ni, Kun Wang, Longcai Wang, Yan Zhang, Yang Hu, Shuilin Jin, Bao-liang Sun, Guiyou Liu (Handling Associate Editor: Jin-Tai Yu)
Impact of Serum Calcium Levels on Alzheimer’s Disease: A Mendelian Randomization Study
Abstract: Background: Altered calcium homeostasis is hypothesized to underlie Alzheimer’s disease (AD). However, it remains unclear whether serum calcium levels are genetically associated with AD risk. Objective: To develop effective therapies, we should establish the causal link between serum calcium levels and AD. Methods: Here, we performed a Mendelian randomization study to investigate the causal association of increased serum calcium levels with AD risk using the genetic variants from a large-scale serum calcium genome-wide association study (GWAS) dataset (61,079 individuals of European descent) and a large-scale AD GWAS dataset (54,162 individuals including 17,008 AD cases and 37,154 controls of European descent). Here, we selected the inverse-variance weighted (IVW) as the main analysis method. Meanwhile, we selected other three sensitivity analysis methods to examine the robustness of the IVW estimate. Results: IVW analysis showed that the increased serum calcium level (per 1 standard deviation (SD) increase 0.5-mg/dL) was significantly associated with a reduced AD risk (OR=0.57, 95% CI 0.35-0.95, p=0.031). Meanwhile, all the estimates from other sensitivity analysis methods were consistent with the IVW estimate in terms of direction and magnitude. Conclusion: In summary, we provided evidence that increased serum calcium levels could reduce the risk of AD. Meanwhile, randomized controlled study should be conducted to clarify whether diet calcium intake or calcium supplement, or both could reduce the risk of AD.
Bernadeth Lyn C. Piamonte* Adrian I. Espiritu*, Veeda Michelle M. Anlacan *These authors contributed equally to this work.
Effects of Citicoline as an Adjunct Treatment for Alzheimer’s Disease: A Systematic Review
Abstract: Background: A critical strategy in the management of Alzheimer’s disease (AD) is optimizing the effects of currently available pharmacologic therapies such as citicoline (CC). Objective: The purpose of this study was to determine the effects of CC as adjunct therapy to cholinesterase inhibitors (AChEI) in the treatment of AD. Methods: We identified relevant studies by electronic search until April 2020. We considered studies with a comparator group that enrolled elderly patients with a diagnosis of AD and employed CC as an adjunct therapy to AChEIs compared to AChEI monotherapy or comparisons of different AChEIs combined with CC. Methodological quality assessment was done using the Newcastle-Ottawa Scale. Results: Out of 149 articles identified, two retrospective cohort studies involving 563 elderly patients affected with AD were included. After 3 months and 9 months, better Mini-Mental Status Examination scores were observed in the “AChEIs + CC” group versus “AChEIs alone” group. CC combined with donepezil may be better in improving cognition than when combined with rivastigmine. No significant difference was noted in terms of activities of daily living (ADL) and instrumental-ADL. Neuropsychiatric Inventory and Geriatric Depression Scale-short form scores appeared to be lower in the combination treatment versus monotherapy. The adverse events of combined treatment were self-limiting and included occasional excitability, gastric intolerance, and headache. Conclusion: Limited evidence from pooled data of two observational studies suggests that CC used in adjunct with AChEIs in the treatment of AD was well-tolerated and showed improvement in cognition, mood, and behavioral symptoms compared to treating with AChEIs alone.
Tarek K. Rajji, Christopher R. Bowie, Nathan Herrmann, Bruce G. Pollock, Marom Bikson, Daniel M. Blumberger, Meryl A. Butters, Zafiris J. Daskalakis, Corinne E. Fischer, Alastair J. Flint, Angela C. Golas, Ariel Graff-Guerrero, Sanjeev Kumar, Lillian Lourenco, Linda Mah, Shima Ovaysikia, Kevin E. Thorpe, Aristotle N. Voineskos, Benoit H. Mulsant* for the PACt-MD Study Group
Design and Rationale of the PACt-MD Randomized Clinical Trial: Prevention of Alzheimer’s dementia with Cognitive remediation plus transcranial direct current stimulation in Mild cognitive impairment and Depression
Abstract: Background: By the time Alzheimer’s disease and related disorders (ADRD) are diagnosed, efficacy of treatments is limited. Preventive interventions are urgently needed. Objective: To design a randomized controlled trial to assess a novel intervention that aims to prevent ADRD in high-risk groups. Methods: We report on the rationale and describe the design of a multisite randomized controlled trial that aims to prevent ADRD in older persons with: (1) mild cognitive impairment (MCI); (2) remitted major depressive disorder (MDD) without MCI; or (3) remitted MDD with MCI. Results: PACt-MD (Prevention of Alzheimer’s dementia with Cognitive remediation plus transcranial direct current stimulation in Mild cognitive impairment and Depression) is a trial that randomized 375 older participants with MCI, MDD, or MCI+MDD to cognitive remediation (CR) and transcranial direct current stimulation (tDCS) or sham-CR+sham-tDCS for 5 days/week for 8 weeks followed by boosters for 5 days/week once every 6 months until participants progress to MCI or ADRD, or the end of the study. Between boosters, participants are asked to train on CR daily. At baseline, end of 8 weeks, and yearly from baseline, participants undergo clinical, cognitive, and functional assessments. Primary aims are to compare the efficacy of CR+tDCS versus sham+sham in preventing: 1) long-term cognitive decline; and 2) incidence of ADRD or MCI. Secondary aim is to assess for cognitive improvement after the 8-week course. We will also explore the moderating and mediating effects of biomarkers collected from the participants. Conclusion: PACt-MD is unique in combining brain stimulation and psychosocial intervention to prevent ADRD. PACt-MD is also a platform for studying multi-domain biomarkers that will advance our understanding of the relationships among MCI, MDD, and ADRD.
Katelyn Cuttler, Monique J. Bignoux, Tyrone C. Otgaar, Stephanie Chigumba, Eloise Ferreira, Stefan F.T. Weiss
LRP::FLAG Reduces Phosphorylated Tau Levels in Alzheimer’s Disease Cell Culture Models
Abstract: Background: Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) plaque and neurofibrillary tangle formation, respectively. Neurofibrillary tangles form as a result of the intracellular accumulation of hyperphosphorylated tau. Telomerase activity and levels of the human reverse transcriptase (hTERT) subunit of telomerase are significantly decreased in AD. Recently, it has been demonstrated that the 37 kDa/67 kDa laminin receptor (LRP/LR) interacts with telomerase and is implicated in Aβ pathology. Since both LRP/LR and telomerase are known to play a role in the Aβ facet of AD, we hypothesized that they might also play a role in tauopathy. Objective: This study aimed to determine if LRP/LR has a relationship with tau and whether overexpression of LRP::FLAG has an effect on tauopathy-related proteins. Methods: We employed confocal microscopy and FRET to determine whether LRP/LR and tau co-localize and interact. LRP::FLAG overexpression in HEK-293 and SH-S5Y cells as well as analysis of tauopathy-related proteins was assessed by western blotting. Results: We demonstrate that LRP/LR co-localizes with tau in the perinuclear cell compartment and confirmed a direct interaction between LRP/LR and tau in HEK-293 cells. Overexpression of LRP::FLAG in HEK-293 and SH-SY5Y cells decreased total and phosphorylated tau levels with a concomitant decrease in PrPc levels, a tauopathy-related protein. LRP::FLAG overexpression also resulted in increased hTERT levels. Conclusion: This data suggest that LRP/LR extends its role in AD through a direct interaction with tau, and recommend LRP::FLAG as a possible alternative AD therapeutic via decreasing phosphorylated tau levels.
Mami Takemoto, Yasuyuki Ohta, Nozomi Hishikawa, Toru Yamashita, Emi Nomura, Keiichiro Tsunoda, Ryo Sasaki, Koh Tadokoro, Namiko Matsumoto, Yoshio Omote, Koji Abe
The Efficacy of Sertraline, Escitalopram, and Nicergoline in the Treatment of Depression and Apathy in Alzheimer’s Disease: The Okayama Depression and Apathy Project (ODAP)
Abstract: Background: Neuropsychiatric symptoms of dementia such as depression and apathy in patients with Alzheimer’s disease (AD) are associated with a lower quality of life. Objective: We aimed to determine the efficacy of two antidepressants and one antipathy drug in the treatment of depression and apathy in AD patients. Methods: In the present study, we evaluated the efficacy of sertraline (n = 11; average dose = 31.8 mg), escitalopram (n = 13; average dose = 7.3 mg), and nicergoline (n = 9; average dose = 14.5 mg) in treating depression and apathy over a period of 3 months (M). The 33 patients with AD demonstrated high Geriatric Depression Scale (GDS) (>5) or a high Apathy Scale (AS) (>16) scores. Results: The patients receiving escitalopram treatment showed a significant improvement in GDS score from baseline (8.2 ± 3.5) to 3 M (5.7 ± 2.6, p = 0.04), and the patients receiving sertraline treatment showed a significant improvement in AS score from baseline (20.8 ± 5.2) to 3 M (16.8 ± 6.1, p = 0.05); however, no significant changes were noted in patients receiving nicergoline. Conclusion: These results provide novel information on the efficacy of sertraline and escitalopram in the treatment of apathy and depression, respectively, in patients with AD.