Volume 43, Number 4, 2015

Pages 1097-1113

Review

Elena Vicario-Orri, Carlos Opazo, Francisco J. Muñoz

The Pathophysiology of Axonal Transport in Alzheimer’s Disease

Abstract: Neurons communicate in the nervous system by carrying out information along the length of their axons to finally transmit it at the synapse. Proper function of axons and axon terminals relies on the transport of proteins, organelles, vesicles, and other elements from the site of synthesis in the cell body. Conversely, neurotrophins secreted from axonal targets and other components at nerve terminals need to travel toward the cell body for clearance. Molecular motors, namely kinesins and dyneins, are responsible for the movement of these elements along cytoskeletal tracks. Given the challenging structure of neurons, axonal transport machinery plays a crucial role in maintaining neuronal viability and function, allowing the proper neurotransmitter release at the presynaptic ending. On this basis, failure of axonal transport has been proposed as a key player in the development and/or progression of neurodegenerative disorders such as Alzheimer’s disease (AD). Increasing evidence suggests that amyloid-β peptide, a hallmark of AD, may disrupt axonal transport and in so doing, contribute to AD pathophysiology. Here we discuss the molecular mechanisms of axonal transport with specific emphasis on the possible relationship between defective axonal transport and AD.

Pages 1115-1136

Review

Gaurav Bedse, Adele Romano, Angelo M. Lavecchia, Tommaso Cassano, Silvana Gaetani (Handling Associate Editor: Patrizia Mecocci)

The Role of Endocannabinoid Signaling in the Molecular Mechanisms of Neurodegeneration in Alzheimer’s Disease

Abstract: Alzheimer’s disease (AD) is the most common form of progressive neurodegenerative disease characterized by cognitive impairment and mental disorders. The actual cause and cascade of events in the progression of this pathology is not fully determined. AD is multifaceted in nature and is linked to different multiple mechanisms in the brain. This aspect is related to the lack of efficacious therapies that could slow down or hinder the disease onset/progression. The ideal treatment for AD should be able to modulate the disease through multiple mechanisms rather than targeting a single dysregulated pathway. Recently, the endocannabinoid system emerged as novel potential therapeutic target to treat AD. In fact, exogenous and endogenous cannabinoids seem to be able to modulate multiple processes in AD, although the mechanisms that are involved are not fully elucidated. This review provides an update of this area. In this review, we recapitulate the role of endocannabinoid signaling in AD and the probable mechanisms through which modulators of the endocannabinoid system provide their effects, thus highlighting how this target might provide more advantages over other therapeutic targets.

Pages 1137-1148

Review

Yu-Long Lan, Jie Zhao, Shao Li

Update on the Neuroprotective Effect of Estrogen Receptor Alpha Against Alzheimer’s Disease

Abstract: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by memory loss and disordered cognition. Women have a higher AD incidence than men, indicating that the declining estrogen levels during menopause may influence AD pathogenesis. However, the mechanism underlying estrogen’s neuroprotective effect is not fully clarified and is complicated by the presence of several distinct estrogen receptor (ER) types and the identification of a growing number of ER splice variants. Thus, a deeper analysis of ERs could elucidate the role of estrogen in age-related cognitive changes. Intracellular calcium signaling cascades play a pivotal role in ERα neuroprotection against AD. The ERα-mediated inhibition of Death domain-associated protein (Daxx) translocation and the combination of membrane ERα and caveolin in caveolae may protect against AD. Moreover, the voltage-dependent anion channel (VDAC)/ERα association may be important for maintaining channel inactivation and may be relevant in neuronal preservation against Aβ injury. Additionally, ERα may prevent glutamate excitotoxic injury by Aβ through estrogen signaling mechanisms. ERα and IGF-IR co-activation may mediate neuroprotection, and many other growth factors and intracellular signaling responses triggered by ERα may also play important roles in this process. Furthermore, details regarding the genes and mRNA variants of ERα that are expressed in different parts of the human organs have been clarified recently. Therefore, here we review the literature to clarify the neuroprotective role of ERα. This review focuses on the potential mechanisms mediated by ERα in the intracellular signaling events in nervous system cells, thereby clarifying ERα-mediated protections against AD.

Pages 1149-1156

Hypothesis

Roger Deloncle, Olivier Guillard

Is Brain Copper Deficiency in Alzheimer’s, Lewy Body, and Creutzfeldt Jakob Diseases the Common Key for a Free Radical Mechanism and Oxidative Stress-Induced Damage?

Abstract: In Alzheimer’s (AD), Lewy body (LBD), and Creutzfeldt Jakob (CJD) diseases, similar pathological hallmarks have been described, one of which is brain deposition of abnormal protease-resistant proteins. For these pathologies, copper bound to proteins is able to protect against free radicals by reduction from cupric Cu++ to cupreous Cu+. We have previously demonstrated in bovine brain homogenate that free radicals produce proteinase K-resistant prion after manganese is substituted for copper. Since low brain copper levels have been described in transmissible spongiform encephalopathies, in substantia nigra in Parkinson’s disease, and in various brain regions in AD, LBD, and CJD, a mechanism has been proposed that may underlie the neurodegenerative processes that occur when copper protection against free radicals is impaired. In peptide sequences, the alpha acid proton near the peptide bond is highly mobile and can be pulled out by free radicals. It will produce a trivalent α-carbon radical and induce a free radical chain process that will generate a D-amino acid configuration in the peptide sequence. Since only L-amino acids are physiologically present in mammalian and human proteins, it may be supposed that only physiological L-peptides can be recycled by physiological enzymes such as proteases. If a D-amino acid is found in the peptide sequence subsequent to deficient copper protection against free radicals, it will not be recognized and might alter the proteasome L-amino acid recycling from brain peptides. In the brain, there will result an accumulation of abnormal protease-resistant proteins such as those observed in AD, LBD, and CJD.

Pages 1157-1161

Short Communication

Katarina Lejavova, Katarina Ondicova, Lubica Horvathova, Noemi Hegedusova, Veronika Cubinkova, Peter Vargovic, Georg Manz, Peter Filipcik, Boris Mravec, Michal Novak, Richard Kvetnansky

Stress-Induced Activation of the Sympathoadrenal System is Determined by Genetic Background in Rat Models of Tauopathy

Abstract: Stress may accelerate onset of neurodegenerative diseases in vulnerable subjects and, vice versa, neurodegeneration affects the responsiveness to stressors. We investigated the neuroendocrine response to immobilization stress in normotensive Wistar-Kyoto rats (WKY), spontaneously hypertensive rats (SHR), and transgenic rats of respective WKY and SHR strains overexpressing human truncated tau protein. Plasma levels of epinephrine, norepinephrine, and corticosterone were determined. An immobilization-induced elevation of epinephrine and norepinephrine was significantly reduced in WKY transgenic rats compared to WKY wild-type rats, while no differences were seen between SHR transgenic and SHR wild-type animals. Our data have shown that sympathoadrenal system response to stress strongly depends on both tau protein-induced neurodegeneration and genetic background of experimental animals.

Pages 1163-1168

Short Communication

Mallory Gough, Sophee Blanthorn-Hazell, Edward T. Parkin

The Histidine Composition of the Amyloid-β Domain, but not the E1 Copper Binding Domain, Modulates β-Secretase Processing of Amyloid-β Protein Precursor in Alzheimer’s Disease

Abstract: Amyloid-β protein precursor (AβPP) proteolysis by β- and γ-secretases generates neurotoxic amyloid-β (Aβ)-peptides in Alzheimer's disease (AD). We have investigated the role of histidine residues within the extracellular E1 copper binding and Aβ domains of AβPP in its proteolysis. By stably expressing histidine to alanine AβPP mutant constructs in SH-SY5Y cells, we show that mutations in the E1 copper binding domain had no impact on α- or β-secretase processing. Mutation of histidine 14 within the Aβ-domain specifically down-regulated β-secretase processing without impacting on non-amyloidogenic proteolysis. Understanding how histidine 14 participates in AβPP proteolysis may reveal new intervention points for AD treatments.

Pages 1169-1173

Short Communication

Irene Piaceri, Beatrice Raspanti, Andrea Tedde, Silvia Bagnoli, Sandro Sorbi, Benedetta Nacmias (Handling Associate Editor: Daniela Galimberti)

Epigenetic Modifications in Alzheimer’s Disease: Cause or Effect?

Abstract: Alzheimer’s disease (AD) is a multifactorial disorder induced by a combination of genetic and environmental factors, and epigenetic modifications could be the key to understand the pathogenesis of AD. We performed a methylation study of the promoter regions of the three AD principal causative genes in 60 late-onset AD patients and 60 controls. The studied regions in the three causative genes were strongly unmethylated in both groups, but in AD patients the methylation were significantly increased. Our study adds new insights to previous ones by showing the involvement of epigenetic changes in AD, which influence the pathogenesis of the disease.

Pages 1175-1184

Esteve Gallego-Jutglà, Jordi Solé-Casals, François-Benoît Vialatte, Justin Dauwels, Andrzej Cichocki (Handling Associate Editor: Ricardo Bajo)

A Theta-Band EEG Based Index for Early Diagnosis of Alzheimer's Disease

Abstract: Despite recent advances, early diagnosis of Alzheimer’s disease (AD) from electroencephalography (EEG) remains a difficult task. In this paper, we offer an added measure through which such early diagnoses can potentially be improved. One feature that has been used for discriminative classification is changes in EEG synchrony. So far, only the decrease of synchrony in the higher frequencies has been deeply analyzed. In this paper, we investigate the increase of synchrony found in narrow frequency ranges within the θ band. This particular increase of synchrony is used with the well-known decrease of synchrony in the α band to enhance detectable differences between AD patients and healthy subjects. We propose a new synchrony ratio that maximizes the differences between two populations. The ratio is tested using two different data sets, one of them containing mild cognitive impairment patients and healthy subjects, and another one, containing mild AD patients and healthy subjects. The results presented in this paper show that classification rate is improved, and the statistical difference between AD patients and healthy subjects is increased using the proposed ratio.

Pages 1185-1198

Mario Díaz, Noemí Fabelo, Isidre Ferrer, Tomás Gómez, Raquel Marín

Biophysical Alterations in Lipid Rafts from Human Cerebral Cortex Associate with Increased BACE1/AβPP Interaction in Early Stages of Alzheimer’s Disease

Abstract: In the present study, we have assessed the biophysical properties of lipid rafts from different brain areas in subjects exhibiting early neuropathological stages of Alzheimer’s disease (AD). By means of steady-state fluorescence polarization analyses using two environment-sensitive fluorescent probes, we demonstrate that lipid rafts from cerebellum, and frontal and entorhinal cortices, exhibit different biophysical behaviors depending on the stage of the disease. Thus, while membrane anisotropies were similar in the cerebellum along stages, lipid rafts from frontal and entorhinal cortices at AD stages I/II and AD III were significantly more liquid-ordered than in control subjects, both at the aqueous interface and hydrophobic core of the raft membrane. Thermotropic analyses demonstrated the presence of Arrhenius breakpoints between 28.3-32.0°C, which were not influenced by the disease stage. However, analyses of membrane microviscosity (ηapp) demonstrate that frontal and entorhinal lipid rafts are notably more viscous and liquid-ordered all across the membrane from early stages of the disease. These physicochemical alterations in lipid rafts do not correlate with changes in cholesterol or sphingomyelin levels, but to reduced unsaturation index and increased saturate/polyunsaturated ratios in phospholipid acyl chains. Moreover, we demonstrate that β-secretase/AβPP (amyloid-β protein precursor) interaction and lipid raft microviscosity are strongly, and positively, correlated in AD frontal and entorhinal cortices. These observations strengthens the hypothesis that physical properties of these microdomains modulate the convergence of amyloidogenic machinery toward lipid rafts, and also points to a critical role of polyunsaturated fatty acids in amyloidogenic processing of AβPP.

Pages 1199-1213

Maira Gironi, Bruno Borgiani, Elisabetta Farina, Enrica Mariani, Cristina Cursano, Margherita Alberoni, Raffaello Nemni, Giancarlo Comi, Massimo Buscema, Roberto Furlan*, Enzo Grossi* *These authors contributed equally to this work.

A Global Immune Deficit in Alzheimer’s Disease and Mild Cognitive Impairment Disclosed by a Novel Data Mining Process

Abstract: Alzheimer’s disease (AD) is the most common form of dementia, while mild cognitive impairment (MCI) causes a slight but measurable decline in cognitive abilities. A person with MCI has an increased risk of developing AD or another dementia. Thus, it is of medical interest to develop predictive tools to assess this risk. A growing awareness exists that pro-oxidative state and neuro-inflammation are both involved in AD. However, the extent of this relationship is still a matter of debate. Due to the expected non-linear correlations between oxidative and inflammatory markers, traditional statistics is unsuitable to dissect their relationship with the disease. Artificial neural networks (ANNs) are computational models inspired by central nervous system networks, capable of machine learning and pattern recognition. The aim of this work was to disclose the relationship between immunological and oxidative stress markers in AD and MCI by the application of ANNs. Through a machine learning approach, we were able to construct an algorithm to classify MCI and AD with high accuracy. Such an instrument, requiring a small amount of immunological and oxidative-stress parameters, would be useful in the clinical practice. Moreover, applying an innovative non-linear mathematical technique, a global immune deficit was shown to be associated with cognitive impairment. Surprisingly, both adaptive and innate immunity were peripherally defective in AD and MCI patients. From this study, new pathogenetic aspects of these diseases could emerge.

Pages 1215-1228

Cha-Gyun Jung, Kyung-Ok Uhm, Hirofumi Horike, Mi-Jeong Kim, Sachiyo Misumi, Akimasa Ishida, Yoshimoto Ueda, Eun-Kyoung Choi, Yong-Sun Kim, Makoto Michikawa, Hideki Hida

Auraptene Increases the Production of Amyloid-β via c-Jun N-Terminal Kinase-Dependent Activation of γ-Secretase

Abstract: Amyloid-β (Aβ) peptide plays a major role in the pathogenesis of Alzheimer’s disease (AD), and is generated by β- and γ-secretase-mediated proteolytic processing of amyloid-β protein precursor (AβPP). In the present study, we investigated the effect of 118 natural compounds on Aβ production in the medium of HEK293 cells stably expressing human AβPP695 (HEK293-AβPP) using Aβ42 sandwich ELISA to find natural compounds that can modulate Aβ production. We found that a coumarin derivative of citrus fruits, auraptene, increased Aβ production. Treatment of HEK293-AβPP cells and rat primary cortical neurons with auraptene significantly increased the secretion of Aβ40, Aβ42, and the Aβ42/40 ratio. However, auraptene did not change the protein levels of the AβPP processing enzymes, a disintegrin and metalloproteinases 10 (ADAM10, α-secretase), β-site AβPP cleaving enzyme-1 (BACE-1, β-secretase), and presenilin 1 (PS1, γ-secretase component). Auraptene increased the activity of γ-secretase but not that of α- and β-secretase. Furthermore, auraptene enhanced γ-secretase-mediated production of Aβ from AβPP or AβPP-C99, but not through α- and β-secretase. Auraptene also phosphorylated c-Jun N-terminal kinase (JNK), and pretreatment with the JNK inhibitor, SP600125, reduced auraptene-induced γ-secretase activity. Overall, our results suggest that auraptene-mediated activation of JNK may contribute to the production of Aβ by promoting γ-secretase activity.

Pages 1229-1236

Christian Schmidt, Nicole Gerlach, Christoph Peter, Kerim Gherib, Katharina Lange, Tim Fride, Inga Zerr

Cerebrospinal Fluid Apolipoprotein E Concentration and Progression of Alzheimer’s Disease

Abstract: Background/Objective: Apolipoprotein E plays a role in the pathogenesis of Alzheimer’s disease (AD). Cerebrospinal fluid (CSF) and plasma level alterations have been reported in AD patients. In search of a potential biomarker, which would be predictive of cognitive, functional, or motor decline, we analyzed CSF apolipoprotein E (ApoE) levels of AD patients in this regard. Methods: Subjects with newly diagnosed AD enrolled into an observational study were followed up longitudinally. Neuropsychological testing and physical examination were performed annually. In a sub-cohort of patients, where baseline CSF ApoE concentration values were available, multiple regression analyses were used to determine possible associations of CSF ApoE concentration and speed of decline on different cognitive, functional, and motor scales (MMSE, iADL, bADL, GDS, UPDRSIII) adjusting for possible confounders. Results: No association of CSF ApoE levels and speed of decline on the various scales could be established (p=0.09 to 0.88). Nevertheless, the use of neuroleptic drugs could be linked to higher velocity of global and extrapyramidal deterioration (p=0.04 and 0.05 for GDS and UPDRSIII, respectively), but not to other outcomes (MMSE, bADL, and iADL). Conclusion: Herein, CSF ApoE at time of AD diagnosis could not be shown to be a viable biomarker for future cognitive, functional, or motor decline. Expectedly, the use of neuroleptic drugs was associated with detrimental effects.

Pages 1237-1250

Mingqin Zhu, Xiuzhe Wang, Marianne Schultzberg, Erik Hjorth (Handling Associate Editor: Zhongdong Qiao)

Differential Regulation of Resolution in Inflammation induced by Amyloid-β42 and Lipopolysaccharides in Human Microglia

Abstract: Resolution of inflammation terminates the inflammatory response in physiological conditions and promotes restoration and healing of the tissue; however, failure in resolution results in chronic inflammation that may lead to disease. Chronic inflammation mediated by microglia is a feature of Alzheimer’s disease (AD) and can be a pathogenic factor in which both treatment targets and diagnostic markers may be found. In addition, there is evidence that the resolution pathway is altered in AD. It is therefore relevant to investigate whether amyloid-β (Aβ) peptide, the major component of senile plaque in AD brain, may have a negative influence on components of the resolution cascade. In this pursuit, we exposed microglia to Aβ42, and with bacterial lipopolysaccharides (LPS) for comparison with a general infectious stimulus. Differential effects were observed: LPS upregulated components of the resolution pathway including the LXA4 receptor/formyl peptide receptor 2 (ALX/FPR2) and phosphorylated 5-lipoxygenase (p-5-LOX), as well as cholinergic alpha 7 nicotinic receptor (α7nAChR) and peroxisome proliferator-activated receptor (PPAR)-δ whereas Aβ42 had an opposite or insignificant effect. Our results indicate that LPS-induced changes in the microglia were conducive for resolution of inflammation, whereas these responses were absent or suppressed in microglia treated with Aβ42. Further studies may prove if Aβ42-induced dysfunction of resolution in microglia contributes to the impaired resolution in the AD brain, and if stimulation of microglial resolution constitutes a treatment strategy for AD.

Pages 1251-1259

Vladan Bajic, Vesna Mandusic, Elka Stefanova, Ana Bozovic, Radoslav Davidovic, Lada Zivkovic, Andrea Cabarkapa, Biljana Spremo-Potparevic

Skewed X-Chromosome Inactivation in Women Affected by Alzheimer’s Disease

Abstract: X-chromosome instability has been a long established feature in Alzheimer’s disease (AD). Premature centromere division and aneuploidy of the X-chromosome has been found in peripheral blood lymphocytes and neuronal tissue in female AD patients. Interestingly, only one chromosome of the X pair has been affected. These results raised a question, ‘’Is the X-chromosome inactivation pattern altered in peripheral blood lymphocytes of women affected by AD?’’ To address this question, we analyzed the methylation status of androgen receptor promoter which may show us any deviation from the 50:50% X inactivation status in peripheral blood lymphocytes of women with AD. Our results showed skewed inactivation patterns (>90%). These findings suggest that an epigenetic alteration on the inactivation centers of the X-chromosome (or skewing) relates not only to aging, by might be a novel property that could account for the higher incidence of AD in women.

Pages 1261-1270

Mona Haghighi, Amanda Smith, Dave Morgan, Brent Small, Shuai Huang, for the Alzheimer’s Disease Neuroimaging Initiative (ADNI)

Identifying Cost-Effective Predictive Rules of Amyloid-β Level by Integrating Neuropsychological Tests and Plasma-Based Markers

Abstract: Background: Detecting participants who are positive for amyloid-β (Aβ) pathology is germane in designing prevention trials by enriching for those cases that are more likely to be amyloid positive. Existing brain amyloid measurement techniques, such as the Pittsburgh Compound B-positron emission tomography and cerebrospinal fluid, are not reasonable first-line approaches limited by either feasibility or cost. Objective: We aimed to identify simple and cost-effective rules that can predict brain Aβ level by integrating both neuropsychological measurements and blood-based markers. Method: Several decision tree models were built for extracting the predictive rules based on the Alzheimer’s Disease Neuroimaging Initiative cohort. Results: We successfully extracted predictive rules of Aβ level. For cognitive function variables, cases above the 45th percentile in total cognitive score (TOTALMOD), above the 52nd percentile of delayed word recall, and above the 70th percentile in orientation resulted in a group that was highly enriched for amyloid negative cases. Conversely scoring below the 15th percentile of TOTALMOD resulted in a group highly enriched for amyloid positive cases. For blood protein markers, scoring below the 57th percentile for apolipoprotein E (ApoE) levels (irrespective of genotype) enriched two fold for the risk of being amyloid positive. In the high ApoE cases, scoring above the 60th percentile for transthyretin resulted in a group that was >90% amyloid negative. A third decision tree using both cognitive and blood-marker data slightly improved the classification of cases. Conclusion: Our study demonstrated that the integration of the neuropsychological measurements and blood-based markers significantly improved prediction accuracy. The prediction model has led to several simple rules, which have a great potential of being naturally translated into clinical settings such as enrichment screening for AD prevention trials of anti-amyloid treatments.

Pages 1271-1284

Claire Takizawa, Paula L. Thompson, Anneloes van Walsem, Céline Faure, William C. Maier

Epidemiological and Economic Burden of Alzheimer’s Disease: A Systematic Literature Review of Data across Europe and the United States of America

Abstract: Background: Alzheimer’s disease (AD) weighs heavily on health expenditure and is strongly associated with increasing age. Due to population aging, increasing global prevalence of AD will pose huge challenges to public health and elderly care systems in all countries across the world. Objectives: This study aimed to better understand the burden of AD from a healthcare perspective. Methods: A systematic literature review of journal articles published between January 2002 and December 2012 was performed for studies conducted in France, Germany, Italy, The Netherlands, Spain, the United Kingdom (UK), and the United States of America (USA), using Medline, Embase, and the NHS Economic Evaluation Database. Results: 3,288 references were initially retrieved, and 39 epidemiological and 66 economic publications were selected for data extraction. AD incidence rates greatly varied between countries; however, prevalence was more consistent across all included countries, ranging between 3-7%. Overall, medical costs were lower in France compared to other included countries and increased with AD severity, e.g., direct medical costs per year for mild AD ranged from 5,476 int$ in France to 27,380 int$ in Spain. Limitations, such as heterogeneous methodology and missing data, prevented the comparison of results across studies between countries or the conclusion of any trend over time. Conclusion: This review corroborates previous understanding that AD burden is high for both society and healthcare providers. Limitations regarding study heterogeneity restricted conclusions; further research is required. Stakeholders could benefit from new healthcare strategies addressing both epidemiological and economic aspects of AD.

Pages 1285-1292

Fotini Bonoti, Evanthia Tzouvaleka, Konstantinos Bonotis, Filippos Vlachos (Handling Associate Editor: Anjan Chatterjee)

Do Patients with Alzheimer’s Disease Draw like Young Children? An Exploratory Study

Abstract: Background: Previous studies have shown that AD patients present a stepwise regression to their cognitive functioning from a mature adult to that of an infant. Objectives: The present study aimed to compare Alzheimer’s disease (AD) patients’ and 4-10 year old children’s drawing performance, taking into account that drawing is currently considered as a cognitive process and that AD manifests a severe cognitive impairment. Methods: The sample consisted of 10 AD patients and 10 adult controls, as well as of 40 children, divided into 4 age groups (4-, 6-, 8-, and 10-years old). Participants were asked to draw from memory (a) six simple objects, (b) a man, and (c) a tree behind a house. Results: Analysis showed an improvement with age in children’s drawing performance, while controls’ drawing scores were similar to those obtained by older children. On the contrary, drawing performance of AD patients significantly decreased into levels under that of the 4-year old children in drawing errors, or under that of the 8-year old children in drawing a man task and partial occlusion task. Conclusions: The observed regression in AD patients’ drawing performance is discussed in relation to the cognitive deficits accompanying the disease.

Pages 1293-1302

Luz María Peña-Longobardo, Juan Oliva-Moreno

Caregiver Burden in Alzheimer’s Disease Patients in Spain

Abstract: Background: Alzheimer’s disease constitutes one of the leading causes of burden of disease, and it is the third leading disease in terms of economic and social costs. Objective: To analyze the burden and problems borne by informal caregivers of patients who suffer from Alzheimer’s disease in Spain. Data and methods: We used the Survey on Disabilities, Autonomy and Dependency to obtain information on the characteristics of disabled people with Alzheimer’s disease and the individuals who provide them with personal care. Additionally, statistical multivariate analyses using probit models were performed to analyze the burden placed on caregivers in terms of health, professional, and leisure/social aspects. Results: 46% of informal caregivers suffered from health-related problems as a result of providing care, 90% had leisure-related problems, and 75% of caregivers under 65 years old admitted to suffering from problems related to their professional lives. The probability of a problem arising for an informal caregiver was positively associated with the degree of dependency of the person cared for. In the case of caring for a greatly dependent person, the probability of suffering from health-related problems was 22% higher, the probability of professional problems was 18% higher, and there was a 10% greater probability of suffering from leisure-related problems compared to non-dependents. Conclusions: The results show a part of the large hidden cost for society in terms of problems related to the burden lessened by the caregivers. This information should be a useful tool for designing policies focused toward supporting caregivers and improving their welfare.

Pages 1303-1311

Tilly Eichler, Diana Wucherer, Jochen René Thyrian, Ingo Kilimann, Johannes Hertel, Bernhard Michalowsky, Stefan Teipel, Wolfgang Hoffmann

Antipsychotic Drug Treatment in Ambulatory Dementia Care: Prevalence and Correlates

Abstract: Background: The present study is the first to analyze primary data about the use of antipsychotic drugs among community dwelling people with dementia in German primary care. Objectives: To determine (1) prevalence of antipsychotic drug treatment in German primary care patients who screened positive for dementia and (2) factors associated with antipsychotic drug treatment. Methods: DelpHi-MV (Dementia: life- and person-centered help in Mecklenburg-Western Pomerania) is an ongoing general practitioner-based, randomized, controlled intervention trial. A total of 4,064 community dwelling patients (≥70 years) recruited from 108 participating practices were screened for dementia (DemTect<9). Of 692 eligible patients (17%), a total of 406 patients provided informed consent (59%). Present analyses are based on data of 243 patients who completed baseline assessment before January 2014 (preliminary data). Results: Of the 243 patients who screened positive for dementia, a total of 25 patients (10%) received at least one antipsychotic drug. Atypical antipsychotic drugs (64%) were prescribed more often than typical antipsychotic drugs (36%). The results of the multivariate analysis showed that treatment by a specialist (neurologist/psychiatrist) was the only factor significantly associated with antipsychotic drug treatment (odds ratio, 12.86; p<0.05; 95% confidence interval, 1.04-158.71). Conclusions: Compared to the antipsychotic drug treatment rate among people with dementia living in nursing homes (> 50%), the rate we found for community dwelling primary care patients who screened positive for dementia was low. Further research is needed to evaluate if these patients are adequately treated or if the antipsychotic drug treatment should and could be further reduced.

Pages 1313-1323

Emilia Salvadori, Anna Poggesi, Giovanni Pracucci, Domenico Inzitari, Leonardo Pantoni, on behalf of the VMCI-Tuscany Study Group* (Handling Associate Editor: Daniela Galimberti)

Development and Psychometric Properties of a Neuropsychological Battery for Mild Cognitive Impairment with Small Vessel Disease: The VMCI-Tuscany Study

Abstract: Background and Objective: Vascular cognitive impairment may have a selective neuropsychological profile. We developed a battery for assessing mild cognitive impairment (MCI) in patients with small vessel disease (SVD), its applicability, and psychometric properties. Methods: Among those proposed by the 2006 NINDS-CSN Consensus Conference, we selected tests for which norms based on healthy Italians and equivalent scores methodology were available. Confirmatory factor analysis was applied to ascertain the fit of the theoretically assumed dimensions to empirical data and to derive each cognitive dimension compound measures. Results: The entire battery was applied to 146 out of a cohort of 201 patients with MCI and SVD. Most tests showed good applicability. Fifty-five patients, who were older and cognitively more impaired, proved unable to complete the Trail Making Test part B, the Rey-Osterrieth Complex Figure, and the Stroop test, and were excluded from the analysis. Among the remaining patients, Mini-Mental State Examination proved largely normal, while Rey-Osterrieth Complex Figure, Symbol digit modalities test, and Trail Making Test part B resulted those most frequently abnormal. Confirmatory factor analysis showed a good fit of the 4-factor theoretical model to empirical data. Praxis domain resulted in the highest percentage of abnormal performance (65%), followed by Memory and Attention/EF domains (19% and 15%), and Language (8%). Conclusions: Our battery proved to be comprehensive, robust, and applicable. Attention-executive dysfunction and impaired memory and visuo-constructional abilities, were the prominent features. The assessment of the Consensus Conference, that included Trial Making Test, looks poorly applicable to older and cognitively impaired patients.

Pages 1325-1330

Jun Ni, Eithan Auriel, Sergi Martinez-Ramirez, Boris Keil, Anne K. Reed, Panagiotis Fotiadis, Edip Mahmut Gurol, Steven M. Greenberg, Anand Viswanathan (Handling Associate Editor: William Van Nostrand)

Cortical Localization of Microbleeds in Cerebral Amyloid Angiopathy: An Ultra High-Field 7T MRI Study

Abstract: The extent of cortical involvement of cerebral amyloid angiopathy (CAA)-related microbleeds (CMBs) remains unclear. We examined five consecutive patients with probable CAA and three non-demented elderly subjects with ultra-high-field 7T MRI, to identify the precise location of CAA-related CMBs. In five CAA patients, 169 of a total of 170 lobar CMBs were located in cortical areas on 7T MRI, while a precise cortical versus juxtacortical localization was unable to be determined for 50/76 CMBs observed by conventional MRI. 7T MRI demonstrates that nearly all lobar CMBs are located in cortex in CAA.

Pages 1331-1341

Kim Henriksen, Inger Byrjalsen, Claus Christiansen, Morten Asser Karsdal

Relationship between Serum Levels of Tau Fragments and Clinical Progression of Alzheimer’s Disease

Abstract: Enzyme-generated fragments of tau have been linked to neuronal death and may serve as serum biomarkers of cognitive loss. Two competitive ELISAs detecting an ADAM10-generated fragment (Tau-A) or a caspase-3-generated fragment (Tau-C) were measured in baseline serum samples from patients with mild to moderate Alzheimer’s disease (AD) from a Phase III clinical trial, and correlated to change in the Alzheimer’s Disease Assessment Scale-Cognitive subscale (ADAS-Cog11) and Clinical Dementia Rating–Sum of Boxes (CDR-SB) over a 64-week period using an MMRM-analysis. Relationship between the biomarkers and changes in ADAS-Cog11 score as a function of time were observed for Tau-C and change in ADAS-Cog11 (p=0.06), and for Tau-A and change in CDR-SB (p=0.04). The correlation of Tau-A/Tau-C ratio with cognitive change assessed by ADAS-Cog11 was even more significant (p<0.006). These data indicate that measuring the balance between tau fragments in serum may provide a marker of the rate of progression of AD and warrant studies in larger cohorts.

Pages 1343-1353

Christian-Alexandre Castellano, Scott Nugent, Nancy Paquet, Sébastien Tremblay, Christian Bocti , Guy Lacombe, Hélène Imbeault, Éric Turcotte, Tamas Fulop, Stephen C. Cunnane (Handling Associate Editor: David Knopman)

Lower Brain 18F-Fluorodeoxyglucose Uptake But Normal 11C-Acetoacetate Metabolism in Mild Alzheimer’s Disease Dementia

Abstract: Background: The cerebral metabolic rate of glucose (CMRg) is lower in specific brain regions in Alzheimer’s disease (AD). The ketones, acetoacetate and β-hydroxybutyrate, are the brain’s main alternative energy substrates to glucose. Objective: To gain insight into brain fuel metabolism in mild AD dementia by determining whether the regional CMR and the rate constant of acetoacetate (CMRa and Ka, respectively) reflect the same metabolic deficit reported for cerebral glucose uptake (CMRg and Kg). Methods: Mild AD dementia (Mild AD; n=10, age 76 y) patients were compared with gender- and age-matched cognitively normal older adults (Controls; n=29, age 75 y) using a PET/MRI protocol and analyzed with both ROI- and voxel-based methods. Results: ROI-based analysis showed 13% lower global CMRg in the gray matter of mild AD dementia versus Controls (34.2 ± 5.0 versus 38.3 ± 4.7 µmol/100 g/min, respectively; p = 0.015), with CMRg and Kg in the parietal cortex, posterior cingulate, and thalamus being the most affected (p ≤ 0.022). Neither global nor regional CMRa or Ka differed between the two groups (all p ≥ 0.188). Voxel-based analysis showed a similar metabolic pattern to ROI-based analysis with seven clusters of significantly lower CMRg in the mild AD dementia group (uncorrected p ≤ 0.005) but with no difference in CMRa. Conclusion: Regional brain energy substrate hypometabolism in mild AD dementia may be specific to impaired glucose uptake and/or utilization. This suggests a potential avenue for compensating brain energy deficit in AD dementia with ketones.

Pages 1355-1373

Julia Muenchhoff, Anne Poljak, Fei Song, Mark Raftery, Henry Brodaty, Mark Duncan, Mark McEvoy, John Attia, Peter W. Schofield, Perminder S. Sachdev

Plasma Protein Profiling of Mild Cognitive Impairment and Alzheimer’s Disease Across Two Independent Cohorts

Abstract: To unlock the full potential of disease modifying treatments, it is essential to develop early biomarkers for Alzheimer’s disease (AD). For practical reasons, blood-based markers that could provide a signal at the stage of mild cognitive impairment (MCI) or even earlier would be ideal. Using the proteomic approach of isobaric tagging for relative and absolute quantitation (iTRAQ), we compared the plasma protein profiles of MCI, AD, and cognitively normal control subjects from two independent cohorts: the Sydney Memory and Ageing Study (261 MCI subjects, 24 AD subjects, 411 controls) and the Hunter Community Study (180 MCI subjects, 153 controls). The objective was to identify any proteins that are differentially abundant in MCI and AD plasma in both cohorts, since they might be of interest as potential biomarkers, or could help direct future mechanistic studies. Proteins representative of biological processes relevant to AD pathology, such as the complement system, the coagulation cascade, lipid metabolism, and metal and vitamin D and E transport, were found to differ in abundance in MCI. In particular, levels of complement regulators C1 inhibitor and factor H, fibronectin, ceruloplasmin, and vitamin D-binding protein were significantly decreased in MCI participants from both cohorts. Several apolipoproteins, including apolipoprotein AIV, B-100, and H were also significantly decreased in MCI. Most of these proteins have previously been reported as potential biomarkers for AD; however, we show for the first time that a significant decrease in plasma levels of two potential biomarkers (fibronectin and C1 inhibitor) is evident at the MCI stage.

Pages 1375-1392

Vera F. Monteiro-Cardoso, M. Manuel Oliveira, Tânia Melo, Maria R.M. Domingues, Paula I. Moreira, Elisabete Ferreiro, Francisco Peixoto, Romeu A. Videira

Cardiolipin Profile Changes are Associated to the Early Synaptic Mitochondrial Dysfunction in Alzheimer’s Disease

Abstract: Brain mitochondria are fundamental to maintaining healthy functional brains, and their dysfunction is involved in age-related neurodegenerative disorders such as Alzheimer’s disease (AD). In this study, we conducted a study on how both non-synaptic and synaptic mitochondrial functions are compromised at an early stage of AD-like pathologies and their correlation with putative changes on membranes lipid profile, using 3 month-old nontransgenic and 3xTg-AD mice, a murine model of experimental AD. Bioenergetic dysfunction in 3xTg-AD brains is evidenced by a decrease of brain ATP levels resulting, essentially, from synaptic mitochondria functionality disruption as indicated by declined respiratory control ratio associated with a 50% decreased complex I activity. Lipidomics studies revealed that synaptic bioenergetic deficit of 3xTg-AD brains is accompanied by alterations in the phospholipid composition of synaptic mitochondrial membranes, detected either in phospholipid class distribution or in the phospholipids molecular profile. Globally, diacyl- and lyso-phosphatidylcholine lipids increase while ethanolamine plasmalogens and cardiolipins content drops in relation to nontransgenic background. However, the main lipidomic mark of 3xTg-AD brains is that cardiolipin cluster-organized profile is lost in synaptic mitochondria due to a decline of the most representative molecular species. In contrast to synaptic mitochondria, results support the idea that non-synaptic mitochondria function is preserved at the age of 3 months. Although the genetically construed 3xTg-AD mouse model does not represent the most prevalent form of AD in humans, the present study provides insights into the earliest biochemical events in AD brain, connecting specific lipidomic changes with synaptic bioenergetic deficit that may contribute to the progressive synapses loss and the neurodegenerative process that characterizes AD.

Pages 1393-1402

Steinunn Thordardottir, Anne Kinhult Ståhlbom, Daniel Ferreira, Ove Almkvist, Eric Westman, Henrik Zetterberg, Maria Eriksdotter, Kaj Blennow, Caroline Graff

Preclinical Cerebrospinal Fluid and Volumetric Magnetic Resonance Imaging Biomarkers in Swedish Familial Alzheimer’s Disease

Abstract: Background: It is currently believed that therapeutic interventions will be most effective when introduced at the preclinical stage of Alzheimer’s disease (AD). This underlines the importance of biomarkers to detect AD pathology in vivo before clinical disease onset. Objective: To examine the evolution of cerebrospinal fluid (CSF) biomarker and brain structure changes in the preclinical phase of familial AD. Methods: The study included members from four Swedish families at risk for carrying an APPswe, APParc, PSEN1 H163Y, or PSEN1 I143T mutation. Magnetic resonance imaging (MRI) scans were obtained from 13 mutation carriers (MC) and 20 non-carriers (NC) and analyzed using vertex-based analyses of cortical thickness and volume. CSF was collected from 10 MC and 12 NC from familial AD families and analyzed for Aβ42, total tau (T-tau) and phospho-tau (P-tau). Results: The MC had significantly lower levels of CSF Aβ42 and higher levels T-tau and P-tau than the NC. There was a trend for a decrease in Aβ42 15–20 years before expected onset of clinical symptoms, while increasing T-tau and P-tau was not found until close to the expected clinical onset. The MC had decreased volume on MRI in the left precuneus, superior temporal gyrus, and fusiform gyrus. Conclusions: Aberrant biomarker levels in CSF as well as regional brain atrophy are present in preclinical familial AD, several years before the expected onset of clinical symptoms.

Pages 1403-1412

Ji-ping Tan*, Nan Li*, Jing Gao, Lu-ning Wang, Yi-ming Zhao, Bao-cheng Yu, Wei Du, Wen-jun Zhang, Lian-qi Cui, Qing-song Wang, Jian-jun Li, Jin-sheng Yang, Jian-min Yu, Xiang-nan Xia, Pei-yi Zhou *These authors contributed equally to this manuscript.

Optimal Cutoff Scores for Dementia and Mild Cognitive Impairment of the Montreal Cognitive Assessment among Elderly and Oldest-Old Chinese Population

Abstract: Background: All versions of the Montreal Cognitive Assessment (MoCA) lack population-based data of 80-plus individuals. The norms and cut-off scores for mild cognitive impairment (MCI) and dementia of the MoCA are different among five Chinese versions. Objective: To provide the cut-off scores in detecting MCI and dementia of the Peking Medical Union College Hospital version of the MoCA (MoCA-P). Methods: In a cross-sectional survey, Chinese veterans aged ≥60 years completed the MoCA-P and the Mini-Mental State Examination (MMSE). Results: Among 7,445 elderly veterans, 5,085 (68.30%) were aged ≥80 years old, 2,621 (35.20%) had 6 years of education or less, 6,847 (91.97%) were male, and 2,311 (31.04%) and 984 (13.22%) veterans were diagnosed as having MCI and dementia, respectively. Adding two points and one point to the MoCA scores for the primary and middle school groups, respectively, can fully adjust for the notable impact of education but cannot compensate for the effect of age. In the three age groups (60-79, 80-89, and ≥90 years old), the optimal MoCA-P cut-off scores for detecting MCI were ≤25, ≤24, and ≤23, respectively, and for detecting dementia were ≤24, ≤21, and ≤19, respectively, which demonstrated relatively high sensitivities and specificities. The areas under the curves for the MoCA-P for detecting MCI and dementia (0.937 and 0.908, respectively) were greater than those for the MMSE (0.848 and 0.892, respectively). Conclusion: Compared with the MMSE, the MoCA-P is significantly better for detecting MCI in the elderly, particularly in the oldest old population, and it also displays more effectiveness in detecting dementia.

Pages 1413-1427

Quan Ma*, Ming Ying*, Xiaojing Sui, Huimin Zhang, Haiyan Huang, Linqing Yang, Xinfeng Huang, Zhixiong Zhuang, Jianjun Liu, Xifei Yang *These authors contributed equally to this work.

Chronic Copper Exposure Causes Spatial Memory Impairment, Selective Loss of Hippocampal Synaptic Proteins, and Activation of PKR/eIF2α Pathway in Mice

Abstract: Copper is an essential element for human growth and development; however, excessive intake of copper could contribute to neurotoxicity. Here we show that chronic exposure to copper in drinking water impaired spatial memory with simultaneous selective loss of hippocampal pre-synaptic protein synapsin 1, and post-synaptic density protein (PSD)-93/95 in mice. Copper exposure was shown to elevate the levels of nitrotyrosine and 8-hydroxydeoxyguanosine (8-OHdG) in hippocampus, two markers of oxidative stress. Concurrently, we also found that copper exposure activated double stranded RNA-dependent protein kinase (PKR) as evidenced by increased ratio of phosphorylated PKR at Thr451 and total PKR and increased the phosphorylation of its downstream signaling molecule eukaryotic initiation factor 2α (eIF2α) at Ser51 in hippocampus. Consistent with activation of PKR/eIF2α signaling pathway which was shown to mediate synaptic deficit and cognitive impairment, the levels of activating transcription factor 4 (ATF-4), a downstream signaling molecule of eIF2α and a repressor of CREB-mediated gene expression, were significantly increased, while the activity of cAMP response elements binding protein (CREB) was inactivated as suggested by decreased phosphorylation of CREB at Ser133 by copper exposure. In addition, the expression of the pro-apoptotic target molecule C/EBP homology protein (CHOP) of ATF-4 was upregulated and hippocampal neuronal apoptosis was induced by copper exposure. Taken together, we propose that chronic copper exposure might cause spatial memory impairment, selective loss of synaptic proteins, and neuronal apoptosis through the mechanisms involving activation of PKR/eIF2α signaling pathway.

Pages 1429-1440

Roberto Santangelo, Elisabetta Coppi, Laura Ferrari, Maria Paola Bernasconi, Patrizia Pinto, Gabriella Passerini, Giancarlo Comi, Giuseppe Magnani (Handling Associate Editor: Diego Albani)

Cerebrospinal Fluid Biomarkers Can Play a Pivotal Role in the Diagnostic Work Up of Primary Progressive Aphasia

Abstract: Background: Three variants of primary progressive aphasia (PPA) have been currently characterized: non fluent/agrammatic (nfv-PPA), semantic (sv-PPA), and logopenic variant (lv-PPA). lv-PPA is most commonly associated with Alzheimer’s disease (AD), while nfv-PPA and sv-PPA are related to frontotemporal lobar degeneration. Objective: We aimed to determine whether cerebrospinal fluid (CSF) amyloid-β42 (Aβ42), total tau protein (t-tau), and phosphorylated tau (p-tau), frequently abnormal in AD, could constitute a useful tool in the PPA diagnostic work up, in order to identify subjects with an underlying AD pathology. Methods: We measured CSF biomarker levels in a group of twenty-eight patients, fourteen lv-PPA, nine nfv-PPA, and five sv-PPA. Results: Since there were no significant differences in any of the parameters investigated between nfv-PPA and sv-PPA, the two groups were considered as one (nfv/sv-PPA). At diagnosis, lv-PPA were older than nfv/sv-PPA patients (mean values: 70.7 versus 64.6 years, p=0.02). CSF biomarker mean concentrations were significantly different in lv-PPA versus nfv/sv-PPA patients (p=0.000): Aβ42: 350.64 versus 661.64 ng/L; tau 631.21 versus 232.71 ng/L; p-tau 101 versus 38.21 ng/L. According to the recent AD diagnostic criteria, (Cummings et al., 2013) eleven lv-PPA and only one nfv/sv-PPA showed a liquoral pattern typical for AD. Finally lv-PPA had CSF biomarker levels very similar to a sample of 72 AD patients from our Department. Conclusions: Our data showed that CSF biomarkers can easily and reliably detect those patients with language disorders due to an underlying AD pathology, thus offering the possibility of targeted therapeutic interventions. However, because of the small sample size, such analyses should be reproduced in larger populations of patients to confirm our data.

Pages 1441-1449

Fei Ma, Tianfeng Wu, Rujuan Miao, Yan yu Xiao, Wenwen Zhang, Guowei Huang

Conversion of Mild Cognitive Impairment to Dementia among Subjects with Diabetes: A Population-Based Study of Incidence and Risk Factors with Five Years of Follow-up

Abstract: Type 2 diabetes mellitus (T2DM) is associated with dementia. Mild cognitive impairment (MCI) is a key determinant in this association. It is not clear whether T2DM increases the risk of conversion from MCI to dementia. We plan to explore the relationship between T2DM-MCI and dementia and identify its potential risk factors. A prospective community-based cohort study was conducted from March 2010 to March 2014, including 634 participants with T2DM-MCI, 261 T2DM participants who were cognitively intact, and 585 MCI participants without diabetes. All cohort members received detailed annual evaluations to detect dementia onset during the 5 years of follow-up. The three cohorts were compared to assess differences in dementia onset. Furthermore, Cox proportional hazards regression was used to identify risk factors for dementia onset in the T2DM-MCI cohort. During follow-up, 152 and 49 subjects developed dementia in the MCI and cognitively-intact cohorts, amounting to an adjusted hazard ratio (HR) of 1.66 (95% CI 1.07–2.26). In a survival analysis of the cohorts, MCI accelerated the median progression to dementia by 2.74 years. In a multivariable analysis of the T2DM-MCI cohort, major risk factors for dementia were age >75 years and longer durations of diabetes, while significantly reduced risks of dementia were associated with oral hypoglycemic agents and HMG-CoA reductase inhibitors. Insulin was not associated with significantly changed risk. T2DM-MCI may aggravate the clinical picture as a concomitant factor. To minimize progression to dementia, it may be worthwhile to target several modifiable diabetes-specific features, such as the duration of disease, glycemic control, and antidiabetic agents.