Eseosa T. Ighodaro, Peter T. Nelson, Walter A. Kukull, Frederick A. Schmitt, Erin L. Abner, Allison Caban-Holt, Shoshana H. Bardach, Derrick C. Hord, Crystal M. Glover, Gregory A. Jicha, Linda J. Van Eldik, Alexander X. Byrd, Anita Fernander
Challenges and Considerations Related to Studying Dementia in African Americans
Abstract: Blacks/African Americans have been reported to be ~2-4 times more likely to develop clinical Alzheimer’s disease (AD) compared to Whites. Unfortunately, study design challenges (e.g., recruitment bias), racism, mistrust of healthcare providers and biomedical researchers, confounders related to socioeconomic status, and other sources of bias are often ignored when interpreting differences in human subjects categorized by race. Failure to account for these factors can lead to misinterpretation of results, reification of race as biology, discrimination, and missed or delayed diagnoses. Here we provide a selected historical background, discuss challenges, present opportunities, and suggest considerations for studying health outcomes among racial/ethnic groups. We encourage neuroscientists to consider shifting away from using biologic determination to interpret data, and work instead toward a paradigm of incorporating both biological and socio-environmental factors known to affect health outcomes with the goal of understanding and improving dementia treatments for Blacks/African Americans and other underserved populations.
Aurélie Le Page, Julie Lamoureux, Karine Bourgade, Eric H. Frost, Graham Pawelec, Jacek M. Witkowski, Anis Larbi, Gilles Dupuis, Tamàs Fülöp (Handling Associate Editor: Milan Fiala)
Polymorphonuclear Neutrophil Functions are Differentially Altered in Amnestic Mild Cognitive Impairment and Mild Alzheimer’s Disease Patients
Abstract: The mechanisms of neurodegeneration in Alzheimer’s disease (AD) remain under investigations. Alterations in the blood-brain barrier facilitate exchanges of inflammatory mediators and immune cells between the brain and the periphery in AD. Here, we report analysis of phenotype and functions of polymorphonuclear neutrophils (PMN) in peripheral blood in amnestic mild cognitive impairment (aMCI, n = 13), patients with mild AD (mAD, n = 15), and healthy elderly controls (n = 13). Results showed an increased expression of CD177 in mAD but not in healthy or aMCI patients. IL-8 stimulated increased expression of the CD11b integrin in PMN of healthy subjects in vitro but PMN of aMCI and mAD patients failed to respond. CD14 and CD16 expression was lower in PMN of mAD but not in aMCI individuals relative to controls. Only PMN of aMCI subjects expressed lower levels of CD88. Phagocytosis toward opsonized E. coli was differentially impaired in PMN of aMCI and mAD subjects whereas the capacity to ingest Dextran particles was absent only in mAD subjects. Killing activity was severely impaired in aMCI and mAD subjects whereas free radical production was only impaired in mAD patients. Inflammatory cytokine (TNFα, IL-6, IL-1β, IL-12p70) and chemokine (MIP-1α, MIP-1β, IL-8) production in response to LPS stimulation was very low in aMCI and nearly absent in mAD subjects. TLR2 expression was low only in aMCI. Our data showed a differentially altered capacity of PMN of aMCI and mAD subjects to respond to pathological aggression that may impact impaired responses associated with AD development.
Stephanie L. Adams, Laurent Benayoun, Kathy Tilton, Olivia R. Chavez, Jayandra J. Himali, Jan Krzysztof Blusztajn, Sudha Seshadri, Ivana Delalle
Methionine Sulfoxide Reductase-B3 (MsrB3) Protein Associates with Synaptic Vesicles and its Expression Changes in the Hippocampi of Alzheimer’s Disease Patients
Abstract: Genome-wide association studies (GWAS) identified susceptibility loci associated with decreased hippocampal volume, and found hippocampal subfield-specific effects at MSRB3 (methionine sulfoxide reductase-B3). The MSRB3 locus was also linked to increased risk for late onset Alzheimer’s disease (AD). In this study, we uncovered novel sites of MsrB3 expression in CA pyramidal layer and arteriolar walls by using automated immunohistochemistry on hippocampal sections from 23 individuals accompanied by neuropathology reports and clinical dementia rating scores. Controls, cognitively intact subjects with no hippocampal neurofibrillary tangles, exhibited MsrB3 signal as distinct but rare puncta in CA1 pyramidal neuronal somata. In CA3, however, MsrB3-immunoreactivity was strongest in the neuropil of the pyramidal layer. These patterns were replicated in rodent hippocampi where ultrastructural and immunohistofluorescence analysis revealed MsrB3 signal associated with synaptic vesicles and colocalized with mossy fiber terminals. In AD subjects, the number of CA1 pyramidal neurons with frequent, rather than rare, MsrB3-immunoreactive somatic puncta increased in comparison to controls. This change in CA1 phenotype correlated with the occurrence of AD pathological hallmarks. Moreover, the intensity of MsrB3 signal in the neuropil of CA3 pyramidal layer correlated with the signal pattern in neurons of CA1 pyramidal layer that was characteristic of cognitively intact individuals. Finally, MsrB3 signal in the arteriolar walls in the hippocampal white matter decreased in AD patients. This characterization of GWAS-implicated MSRB3 protein expression in human hippocampus suggests that patterns of neuronal and vascular MsrB3 protein expression reflect or underlie pathology associated with AD.
Ratko Radakovic, John M. Starr, Sharon Abrahams (Handling Associate Editor: Gianfranco Spalletta)
A Novel Assessment and Profiling of Multidimensional Apathy in Alzheimer’s Disease
Abstract: Background: Apathy is a complex multidimensional syndrome frequently reported in Alzheimer’s disease (AD) and is associated with impaired awareness. Here we present a psychometrically robust method to profile apathy in AD. Objectives: To determine the validity and reliability of a multidimensional apathy measure, the Dimensional Apathy Scale (DAS), and explore the apathy subtype profile and its associations in AD. Methods: 102 people with AD and 55 healthy controls were recruited. Participants completed the DAS, the Apathy Evaluation Scale (AES), Geriatric Depression Short form (GDS-15), and Lawton Instrumental Activities of Daily Living (LIADL). Psychometric properties of the DAS were determined. AD-Control comparison was performed to explore group differences on the DAS. Latent Class Analysis (LCA) was used to explore the profile of apathy in AD. Results: The DAS had a good to excellent Cronbach's standardized alpha (self-rated = 0.85, informant/carer-rated = 0.93) and good convergent and divergent validity against standard apathy (AES) and depression (GDS-15) measures. Group comparison showed people with AD were significantly higher for all apathy subtypes than controls (p < 0.001), and lacking in awareness over all apathy subtype deficits. LCA showed three distinct AD subgroups, with 42.2% in the Executive-Initiation apathy, 28.4% in the Global apathy, and 29.4% in the Minimal apathy group. Conclusions: The DAS is a psychometrically robust method of assessing multidimensional apathy in AD. The apathy profiles in AD are heterogeneous, with additional specific impairments relating to awareness dependent on apathy subtype.
Sherilyn Thibeau, G. Peggy McFall, Richard Camicioli, Roger A. Dixon
Alzheimer’s Disease Biomarkers Interactively Influence Physical Activity, Mobility, and Cognition Associations in a Non-Demented Aging Population
Abstract: Background: Alzheimer’s disease (AD) risk-reduction strategies (e.g., increasing physical activity, improving mobility) have garnered increasing attention in the literature. However, the effect of such modifiable factors on the preclinical trajectories of brain and cognitive health may be moderated by non-modifiable biomarkers associated with AD. Objective: In a longitudinal sample of non-demented older adults, we examine the independent predictors everyday physical activity (EPA) and mobility on executive function (EF) performance and change. Next, we test whether these predictions are modified by interactions between age and AD genetic risk. Methods: This accelerated longitudinal design included adults (n = 532, M age = 70.4, age range 53-95) from the Victoria Longitudinal Study. We tested the independent effects of EPA and Mobility (i.e., gait, balance), moderation by Apolipoprotein E (i.e., APOE ɛ4+, ɛ4-) and age (young-old, middle-old, old-old), and interactions between APOE and age on performance and 9-year change in an EF latent variable. Results: First, higher levels of both EPA and Mobility were associated with better EF performance and less decline. Second, the interaction between age and APOE showed that low EPA and older age was associated with poorer EF performance and steeper EF decline for APOE ɛ4+ carriers, and low mobility was associated with poorer EF performance and steeper EF decline for APOE ɛ4+ carriers than the non-risk carriers. Conclusion: In non-demented older adults, age moderated the effects of both EPA and Mobility on EF performance and change. However, this moderation occurs differentially across APOE4 status.
Nan Zhang, Liling Zhang, Yan Li, Marc L. Gordon, Li Cai, Ying Wang, Mengya Xing, Yan Cheng (Handling Associate Editor: Jia Liu)
Urine AD7c-NTP Predicts Amyloid Deposition and Symptom of Agitation in Patients with Alzheimer’s Disease and Mild Cognitive Impairment
Abstract: Background: Expression of neuronal thread protein (NTP), which is considered to be related to neuritic sprouting and neuronal death, may be elevated in brain tissue, cerebrospinal fluid, and even urine in patients with Alzheimer’s disease (AD). Objective: In this study, we analyzed the correlation between urine AD-associated NTP (AD7c-NTP) level, and amyloid-β (Aβ) deposition, and clinical symptoms in AD and mild cognitive impairment (MCI). Methods: Twenty-two patients with mild to moderate AD and 8 subjects with MCI were recruited. Aβ deposition was measured with [11C]-labeled Pittsburgh compound B (PiB)-positron emission tomography (PET) in all participants. Urine AD7c-NTP levels were measured using enzyme-linked immunosorbent assay. Mini-Mental State Examination (MMSE) and Neuropsychiatric Inventory (NPI) were used to evaluate cognitive function and behavioral psychological symptoms, respectively. Results: Fourteen (63.6%) of AD patients and 2 (25.0%) of MCI subjects were Aβ positive on PiB-PET. There was a significant difference in urine AD7c-NTP level between Aβ positive (2.27 ± 2.22 ng/ml) and negative (0.55 ± 0.60 ng/ml) subjects (p = 0.018). Using 1.46 ng/ml as a cut-off value, 68.8% of Aβ positive subjects showed elevated urine AD7c-NTP level, and 92.9% of Aβ negative subjects showed normal urine AD7c-NTP level. There were no relationships between urine AD7c-NTP level and MMSE and total NPI scores. However, AD7c-NTP level positively correlated with agitation score on NPI. Conclusions: Urine AD7c-NTP had high specificity and moderate sensitivity in predicting Aβ deposition among patients with cognitive impairment. Furthermore, urine AD7c-NTP level strongly correlated with the symptom of agitation.
Tormod Fladby, Lene Pålhaugen, Per Selnes, Knut Waterloo, Geir Bråthen, Erik Hessen, Ina Selseth Almdahl, Kjell-Arne Arntzen, Eirik Auning, Carl Fredrik Eliassen, Ragna Espenes, Ramune Grambaite, Gøril Rolfseng Grøntved, Krisztina Kunszt Johansen, Stein Harald Johnsen, Lisa Flem Kalheim, Bjørn-Eivind Kirsebom, Kai Ivar Müller, Arne Exner Nakling, Arvid Rongve, Sigrid Botne Sando, Nikias Siafarikas, Ane Løvli Stav, Sandra Tecelao, Santiago Timon, Svein Ivar Bekkelund, Dag Aarsland
Detecting At-Risk Alzheimer’s Disease Cases
Abstract: While APOE ε4 is the major genetic risk factor for Alzheimer's disease (AD), amyloid dysmetabolism is an initial or early event predicting clinical disease and is an important focus for secondary intervention trials. To improve identification of cases with increased AD risk, we evaluated recruitment procedures using pathological CSF concentrations of Aβ42 (pAβ) and APOE ε4 as risk markers in a multi-center study in Norway. In total, 490 subjects aged 40-80 y were included after response to advertisements and media coverage or memory clinics' referrals. Controls (n = 164) were classified as normal controls without first-degree relatives with dementia (NC), normal controls with first-degree relatives with dementia (NCFD), or controls scoring below norms on cognitive screening. Patients (n = 301) were classified as subjective cognitive decline or mild cognitive impairment. Subjects underwent a clinical and cognitive examination and MRI according to standardized protocols. Core biomarkers in CSF from 411 and APOE genotype from 445 subjects were obtained. Cases (both self-referrals (n = 180) and memory clinics referrals (n = 87)) had increased fractions of pAβ and APOE ε4 frequency compared to NC. Also, NCFD had higher APOE ε4 frequencies without increased fraction of pAβ compared to NC, and cases recruited from memory clinics had higher fractions of pAβ and APOE ε4 frequency than self-referred. This study shows that memory clinic referrals are pAβ enriched, whereas self-referred and NCFD cases more frequently are pAβ negative but at risk (APOE ε4 positive), suitable for primary intervention.
Christian Werner, Stefanie Wiloth, Nele Christin Lemke, Florian Kronbach, Carl-Philipp Jansen, Peter Oster, Jürgen M Bauer, Klaus Hauer (Handling Associate Editor: Tim Fleiner)
People with Dementia Can Learn Compensatory Movement Maneuvers for the Sit-to-Stand Task: A Randomized Controlled Trial
Abstract: Background: A complex motor skill highly relevant to mobility in everyday life (e.g., sit-to-stand [STS] transfer) has not yet been addressed in studies on motor learning in people with dementia (PwD). Objective: To determine whether a dementia-specific motor learning exercise program enables PwD to learn compensatory STS maneuvers commonly taught in geriatric rehabilitation therapy to enhance patients’ STS ability. Methods: Ninety-seven patients with mild-to-moderate dementia (Mini-Mental State Examination: 21.9 ± 2.9 points) participated in a double-blinded, randomized, placebo-controlled trial with 10-week intervention and 3-month follow-up period. The intervention group (IG, n = 51) underwent a motor learning exercise program on compensatory STS maneuvers specifically designed for PwD. The control group (CG, n = 46) performed a low-intensity motor placebo activity. Primary outcomes were scores of the Assessment of Compensatory Sit-to-stand Maneuvers in People with Dementia (ACSID), which covers the number of recalled and initiated, and of effectively performed compensatory STS maneuvers. Secondary outcomes included temporal and kinematic STS characteristics measured by a body-fixed motion sensor (BFS, DynaPort® Hybrid). Results: The IG significantly improved in all ACSID scores compared to the CG (p < 0.001). Secondary analysis confirmed learning effects for all BFS-based outcomes (p < 0.001-0.006). Learning gains were sustained during follow-up for most outcomes. Conclusion: People with mild-to-moderate dementia can learn and retain compensatory STS maneuvers in response to a dementia-specific motor learning exercise program. This is the first study that demonstrated preserved motor learning abilities in PwD by using a motor skill highly relevant to everyday life.
Konstantin Bloch, Irit Gil-Ad, Alexey Vanichkin, Shay Henry Hornfeld, Nickolay Koroukhov, Michal Taler, Pnina Vardi, Abraham Weizman
Intracerebroventricular Streptozotocin Induces Obesity and Dementia in Lewis Rats: Rat Model of Dementia Associated with Obesity
Abstract: Background: Animal models of dementia associated with metabolic abnormalities play an important role in understanding the bidirectional relationships between these pathologies. Rodent strains develop cognitive dysfunctions without alteration of peripheral metabolism following intracerebroventricular administration of streptozotocin (icv-STZ). Objective. We aimed to estimate the effect of icv-STZ on cognitive functions and peripheral metabolism in Lewis rats, which are rarely used for the induction of cognitive abnormalities. Methods. Inbred adult Lewis rats were treated with single icv-STZ (3 mg/kg). Cognitive functions were assessed using Morris water maze (MWM) test and locomotion by the Open Field test. Metabolic alterations were studied using histological and biochemical analysis of brain and peripheral tissues. Results: The icv-STZ induced rapid weight decline during the first two weeks. Thereafter, the rats showed an accelerated weight gain. Three months after the icv-STZ treatment, the rats were severely obese and revealed fatty liver, pancreatic islet hypertrophy, significantly elevated levels of blood insulin, leptin, and adiponectin, but intact peripheral glucose homeostasis. The icv-STZ rats expressed amyloid-β deposits in blood vessels of leptomeningeal area, microgliosis, astrogliosis, and spongiosis in fimbria-fornix area of hippocampus. Locomotor activities of icv-STZ treated and sham-operated rats were similar. In the MWM test, the icv-STZ treated rats demonstrated severely impaired spatial learning during both acquisition and reversal phases. Conclusions: Icv-STZ treated Lewis rats develop severe dementia associated with obesity and peripheral metabolic abnormalities. This animal model may be useful for exploring the pathophysiological relationship between obesity and dementia and provides a new tool for development of effective therapy.
Mustafa Atee, Kreshnik Hoti, Richard Parsons, Jeffery D. Hughes (Handling Associate Editor: Alba Malara)
Pain Assessment in Dementia: Evaluation of a Point-of-Care Technological Solution
Abstract: Pain is common among people with moderate to severe dementia, but inability of patients to self-report means it often goes undetected and untreated. We developed the electronic Pain Assessment Tool (ePAT) to address this issue. A point-of-care App, it utilizes facial recognition technology to detect facial micro-expressions indicative of pain. ePAT also records the presence of pain-related behaviors under five additional domains (Voice, Movement, Behavior, Activity, and Body). In this observational study, we assessed the psychometric properties of ePAT compared to the Abbey Pain Scale (APS). Forty aged care residents (70% females) over the age of 60 years, with moderate to severe dementia and a history of pain-related condition(s) were recruited into the study. Three hundred and fifty-three paired pain assessments (either at rest or post-movement) were recorded and analyzed. The ePAT demonstrated excellent concurrent validity (r = 0.882, 95% CI: 0.857 - 0.903) and good discriminant validity. Inter-rater reliability score was good overall (weighted = 0.74, 95% CI: 0.68-0.80) while internal consistency was excellent. ePAT has psychometric properties which make it suitable for use in non-communicative patients with dementia. ePAT also has the advantage of automated facial expression assessment which provides objective and reproducible evidence of the presence of pain.
Enrica Cavedo, Per Suppa, Catharina Lange, Roland Opfer, Simone Lista, Samantha Galluzzi, Adam J Schwarz, Lothar Spies, Ralph Buchert*, Harald Hampel* for the Alzheimer’s Disease Neuroimaging Initiative (Handling Associate Editor: Babak Ardekani) *These authors contributed equally as senior authors.
Fully Automatic MRI-Based Hippocampus Volumetry Using FSL-FIRST: Intra-Scanner Test-Retest Stability, Inter-Field Strength Variability, and Performance as Enrichment Biomarker for Clinical Trials Using Prodromal Target Populations at Risk for Alzheimer’s Disease
Abstract: Background: MRI-based hippocampus volume is a core clinical biomarker for identification of Alzheimer’s disease (AD). Objective: To assess robustness of automatic hippocampus volumetry with the freely available FSL-FIRST software with respect to short-term repeat and across field strength imaging. FSL-FIRST hippocampus volume (FIRST-HV) was also evaluated as enrichment biomarker for mild cognitive impairment (MCI) trials. Methods: Robustness of FIRST-HV was assessed in 51 healthy controls (HC), 74 MCI subjects, and 28 patients with AD dementia from ADNI1, each with two pairs of back-to-back scans, one at 1.5T one at 3T. Enrichment performance was tested in a second sample of 287 ADNI MCI subjects. Results: FSL-FIRST worked properly in all four scans in 147 out of 153 subjects of the first sample (49 HC, 72 MCI, 26 AD). In these subjects, FIRST-HV did not differ between the first and the second scan within an imaging session, neither at 1.5T nor at 3T (p ≥ 0.302). FIRST-HV was on average 0.78% larger at 3T compared to 1.5T (p = 0.012). The variance of the FIRST-HV difference was larger in the inter-field strength setting than in the intra-scanner settings (p < 0.0005). Computer simulations suggested that the additional variability encountered in the inter-field strength scenario does not cause a relevant degradation of FIRST-HV’s prognostic performance in MCI. FIRST-HV based enrichment resulted in considerably increased effect size of the 2-years change of cognitive measures. Conclusion: The impact of intra-scanner test-retest and inter-field strength variability of FIRST-HV on clinical tasks is negligible. In addition, FIRST-HV is useful for enrichment in clinical MCI trials.
Evi Paouri, Ourania Tzara, Sofia Zenelak, Spiros Georgopoulos
Genetic Deletion of Tumor Necrosis Factor-α Attenuates Amyloid-β Production and Decreases Amyloid Plaque Formation and Glial Response in the 5XFAD Model of Alzheimer’s Disease
Abstract: Increasing evidence suggests that neuroinflammation comprises a major characteristic of Alzheimer’s disease (AD). Tumor necrosis factor-α (TNF-α) is a pleiotropic pro-inflammatory cytokine implicated in neurodegenerative diseases including AD, and has been proposed as a potent therapeutic target for AD. Although a number of studies focusing on pharmacological or genetic manipulation of TNF-α and its receptors in AD mice have provided significant knowledge regarding the role of TNF-α signaling pathway in the pathogenesis of AD, the consequences of TNF-α genetic deletion have not been thoroughly examined. Here, we focused on the effect of TNF-α deficiency on the amyloid phenotype of 5XFAD mice. Our analysis revealed that amyloid deposition, amyloid-β (Aβ) levels, and AβPP-carboxyterminal fragments are significantly reduced in the brains of 5XFAD/TNF-α-/- mice compared to the 5XFAD/TNF-α+/+. We found decreased protein levels of β- and α-secretases in the 5XFAD/TNF-α-/- brains, suggesting for an effect of TNF-α on AβPP processing and Aβ generation. We also show for the first time that TNF-α affects PS1in vivo, as 5XFAD mice lacking TNF-α expression display reduced PS1-carboxyterminal fragments implying for diminished PS1 activity. Moreover, TNF-α deficiency decreases microglial and astrocytic activation and significantly restricts the phagocytic activity of macrophages against Aβ, supporting for reduced responsiveness of phagocytes toward Aβ. Overall, our results reveal that TNF-α genetic deletion in 5XFAD mice attenuates amyloid plaque formation by lowering Aβ generation through the reduction of functionally active PS1 and β-secretase rather than promoting Aβ clearance by phagocytic cells. Our data further suggest TNF-α inhibition as a therapeutic approach for AD.
Roberto Santangelo, Giordano Cecchetti, Maria Paola Bernasconi, Rosalinda Cardamone, Alessandra Barbieri, Patrizia Pinto, Gabriella Passerini, Francesco Scomazzoni, Giancarlo Comi, Giuseppe Magnani (Handling Associate Editor: Willemijn Jansen)
Cerebrospinal Fluid Amyloid-β 42, Total Tau, and Phosphorylated Tau are Low in Patients with Normal Pressure Hydrocephalus: Analogies and Differences with Alzheimer’s Disease
Abstract: Co-existence of Alzheimer’s disease (AD) in normal pressure hydrocephalus (NPH) is a frequent finding, thus a common pathophysiological basis between AD and NPH has been postulated. We measured CSF amyloid-β 42 (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau) concentrations in a sample of 294 patients with different types of dementia and 32 subjects without dementia. We then compared scores on neuropsychological tests of NPH patients with pathological and normal CSF Aβ42 values. Aβ42 levels were significantly lower in NPH than in control patients, with no significant differences between AD and NPH. On the contrary, t-tau and p-tau levels were significantly lower in NPH than in AD, with no differences between NPH and controls. NPH patients with pathological Aβ42 levels did not perform worse than NPH patients with normal Aβ42 levels in any cognitive domains. Our data seem to support the hypothesis of amyloid accumulation in brains of NPH patients. Nevertheless, amyloid does not seem to play a pathogenetic role in the development of cognitive deficits in NPH.
Anne-Marie Miller, Mircea Balasa, Kaj Blennow, Mary Gardiner, Aleksandra Rutkowska, Philip Scheltens, Charlotte E. Teunissen, Pieter Jelle Visser, Bengt Winblad, Gunhild Waldemar, Brian Lawlor
Current Approaches and Clinician Attitudes to the Use of Cerebrospinal Fluid Biomarkers in Diagnostic Evaluation of Dementia in Europe
Abstract: Background: BIOMARKAPD seeks to diminish the barriers associated with the clinical use of cerebrospinal fluid (CSF) biomarker analysis by reducing variation in CSF laboratory methodologies and generating consensus recommendations on their clinical interpretation and application for dementia diagnosis. Objective: To examine the disparity in practitioner attitudes and clinical practice relating to the use of CSF biomarkers for dementia diagnosis across Europe. Methods: Clinical dementia experts were surveyed on the prevalence of national consensus guidelines and analytical reimbursement across Europe; their biomarker platform preferences, lumbar puncture methodologies, and application of reference values and cut-offs for CSF analysis. Results: 74% of respondents (total n=51) use CSF biomarkers in clinical practice and 69% performed lumbar punctures on an outpatient basis. Most use CSF biomarkers to diagnose atypical (84%) and early onset cases of cognitive impairment (71%) and for the differential diagnosis of other dementias (69%). 82% state they are sufficiently informed about CSF biomarkers yet 61% report a lack of national consensus guidelines on their use for dementia diagnosis. 48% of countries represented do not reimburse clinical CSF analysis. 43% report using normal reference ranges derived from publications. Conclusion: Variations in attitude and practice relating to CSF biomarkers, widely recognized as barriers to their clinical acceptance, remain evident within and between countries across Europe, even in expert centers. These shortcomings must be addressed by developing consensus guidelines on CSF-related methodologies and their clinical application to further their use for the diagnostic evaluation of dementia.
Alexander J. Beagle*, Sonja M. Darwish*, Kamalini G. Ranasinghe, Alice L. La, Elissaios Karageorgiou, Keith A. Vossel (Handling Associate Editor: Benjamin Cretin) *These authors contributed equally to this work.
Relative Incidence of Seizures and Myoclonus in Alzheimer's Disease, Dementia with Lewy Bodies, and Frontotemporal Dementia
Abstract: Background: Patients with Alzheimer’s disease (AD) are more prone to seizures and myoclonus, but relative risk of these symptoms among other dementia types is unknown. Objective: To determine incidence of seizures and myoclonus in the three most common neurodegenerative dementias: AD, dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD). Methods: Our institution’s medical records were reviewed for new-onset unprovoked seizures and myoclonus in patients meeting criteria for AD (n=1,320), DLB (n=178), and FTD (n=348). Cumulative probabilities of developing seizures and myoclonus were compared between diagnostic groups, whereas age-stratified incidence rates were determined relative to control populations. Results: The cumulative probability of developing seizures after disease onset was 11.5% overall, highest in AD (13.4%) and DLB (14.7%) and lowest in FTD (3.0%). The cumulative probability of developing myoclonus was 42.1% overall, highest in DLB (58.1%). The seizure incidence rates, relative to control populations, were nearly 10-fold in AD and DLB, and 6-fold in FTD. Relative seizure rates increased with earlier age-at-onset in AD (age <50, 127-fold; 50-69, 21-fold; 70+, 2-fold) and FTD (age <50, 53-fold; 50-69, 9-fold), and relative myoclonus rates increased with earlier age-at-onset in all groups. Seizures began an average of 3.9 years after the onset of cognitive or motor decline, and myoclonus began 5.4 years after onset. Conclusions: Seizures and myoclonus occur with greater incidence in patients with AD, DLB, and FTD than in the general population, but rates vary with diagnosis, suggesting varied pathomechanisms of network hyperexcitability. Patients often experience these symptoms early in disease, suggesting hyperexcitability could be an important target for interventions.
Taiki Sugimoto, Akinori Nakamura, Takashi Kato, Kaori Iwata, Naoki Saji, Yutaka Arahata, Hideyuki Hattori, Masahiko Bundo, Kengo Ito, Shumpei Niida, Takashi Sakurai; MULNIAD study group
Decreased Glucose Metabolism in Medial Prefrontal Areas is Associated with Nutritional Status in Patients with Prodromal and Early Alzheimer’s Disease
Abstract: Background: Weight loss is frequently observed in patients with Alzheimer’s disease (AD); however, the underlying mechanisms are not well understood. Objects: To clarify the associations between nutritional status and AD-related brain changes using Pittsburgh Compound-B (PiB)-PET, fluorodeoxyglucose (FDG)-PET, and structural MRI. Methods: The subjects were 34 amyloid-β (Aβ)-positive individuals with mild cognitive impairment or early AD (prodromal/early AD), and 55 Aβ-negative cognitively normal (CN) subjects who attended the Multimodal Neuroimaging for AD Diagnosis (MULNIAD) study. Nutritional status of the subjects was assessed by body mass index and waist to height ratio (waist circumference/height). The associations between nutritional status and brain changes were examined by multiple regression analysis using statistical parametric mapping. Results: In the prodromal/early AD group, nutritional status was significantly positively correlated with regional cerebral glucose metabolism (rCGM) in the medial prefrontal cortices, while different topographical associations were seen in the CN group, suggesting these changes were AD-specific. Aβ deposition and gray matter volume were not significantly associated with nutritional status. Sub-analysis in the prodromal/early AD group demonstrated that fat mass index, but not fat-free mass index, was positively correlated with rCGM in the medial prefrontal areas. Conclusion: This present study provides preliminary results suggesting that hypometabolism in the medial prefrontal areas is specifically associated with AD-related weight loss, and decrease in fat mass may have a key role.
Anne Suzanne Bertens, Behnam Sabayan, Anton J.M. de Craen, Roos C. Van der Mast, Jacobijn Gussekloo
High Sensitivity Cardiac Troponin T and Cognitive Function in the Oldest Old: The Leiden 85-Plus Study
Abstract: Background: Impaired cardiac function has been related to accelerated cognitive decline in late-life. Objective: To investigate whether higher levels of high sensitivity cardiac troponin T (hs-cTnT), a sensitive marker for myocardial injury, are associated with worse cognitive function in the oldest old. Methods: In 455 participants of the population-based Leiden 85-plus Study, hs-cTnT was measured at 86 years. Cognitive function was measured annually during four years with the Mini-Mental State Examination (MMSE). Results: Participants in the highest gender-specific tertile of hs-cTnT had a 2.0-point lower baseline MMSE score than participants in the lowest tertile (95% confidence interval (CI) (95% CI 0.73-3.3), and had a 0.58-point steeper annual decline in MMSE during follow-up (95% CI 0.06-1.1). The associations remained after adjusting for sociodemographic and cardiovascular risk factors excluding those without a history of overt cardiac disease. Conclusion: In a population-based sample of the oldest old, higher levels of hs-cTnT were associated with worse cognitive function and faster cognitive decline, independently from cardiovascular risk factors and a history of overt cardiac disease.
Sara E. Berman, Lindsay R. Clark, Leonardo A. Rivera-Rivera, Derek Norton, Annie M. Racine, Howard A. Rowley, Barbara B. Bendlin, Kaj Blennow, Henrik Zetterberg, Cynthia M. Carlsson, Sanjay Asthana, Patrick Tursk, Oliver Wieben, Sterling C. Johnson (Handling Associate Editor: Ignacio Casado Naranjo)
Intracranial Arterial 4D Flow in Individuals with Mild Cognitive Impairment is Associated with Cognitive Performance and Amyloid Positivity
Abstract: It is becoming increasingly recognized that cerebrovascular disease is a contributing factor in the pathogenesis of Alzheimer’s disease (AD). A unique 4D-Flow magnetic resonance imaging (MRI) technique, phase contrast vastly undersampled isotropic projection imaging (PC VIPR), enables examination of angiographic and quantitative metrics of blood flow in the arteries of the Circle of Willis within a single MRI acquisition. Thirty-eight participants with mild cognitive impairment (MCI) underwent a comprehensive neuroimaging protocol (including 4D-Flow imaging) and a standard neuropsychological battery. A subset of participants (n = 22) also underwent lumbar puncture and had cerebrospinal fluid (CSF) assayed for AD biomarkers. Cut-offs for biomarker positivity in CSF resulting from a receiver operating characteristic curve analysis of AD cases and controls from the larger Wisconsin Alzheimer’s Disease Research Center cohort were used to classify MCI participants as biomarker positive or negative on amyloid-β (Aβ42), total-tau and total-tau/Aβ42 ratio. Internal carotid artery (ICA) and middle cerebral artery (MCA) mean flow were associated with executive functioning performance, with lower mean flow corresponding to worse performance. MCI participants who were biomarker positive for Aβ42 had lower ICA mean flow than did those who were Aβ42 negative. In sum, mean ICA and MCA arterial flow was associated with cognitive performance in participants with MCI and lower flow in the ICA was associated with amyloid positivity. This provides further evidence for vascular health as a contributing factor in the etiopathogenesis of AD, and could represent a point to intervene in the disease process.
Ling Zhang*, Ying Wang*, Xia Xiayu, Changhua Shi, Wei Chen, Nan Song, Xinjing Fu, Rui Zhou, Yan-feng Xu, Lan Huang, Hua Zhu, Yunlin Han, Chuan Qin *These authors contributed equally to this work.
Altered Gut Microbiota in a Mouse Model of Alzheimer’s Disease
Abstract: The topic of gut microbiota is currently attracting considerable interest as a potential factor in Alzheimer’s disease (AD). However, the extent and time course of alterations in the gut microbiota, and their effects on AD pathology remain uncertain. Herein, we compared the fecal microbiomes and fecal short chain fatty acid composition (SCFAs) between wild-type and AD model mice at different ages under strictly controlled specific pathogen free conditions, and also conducted microscopic investigations of intestinal structures. Our results showed that the microbiota composition and diversity were perturbed and the level of SCFAs was reduced in AD mice, predicting alterations in more than 30 metabolic pathways, which may be associated with amyloid deposition and ultrastructural abnormalities in AD mouse intestine. These findings indicate that AD pathology might not only affect brain function directly, but also exacerbate cognitive deficits through reducing the level of SCFAs via alterations of gut microbiota induced by intestinal amyloid deposition. Our data may support a role of gut microbiota, and suggest a novel route for therapeutic intervention in AD.
Hubert Basselerie, Luc Bracoud, Eva Zeestraten, Eva Bouguen, Vera Kiyasova, Maria Pueyo, Christophe Cognard, Hervé Dumas, Raluca Gramada, Pierre Jean Ousset, Bruno Vellas, Fabrice Bonneville
Incident Cerebral Microbleeds on Longitudinal 3T MRI with Susceptibility Weight-Imaging Help to Identify Patients with Mild Cognitive Impairment Progressing to Alzheimer’s Disease
Abstract: Background: The relationship between cerebral microbleeds (CMB) and Alzheimer’s disease (AD) has not yet been clearly determined, particularly with susceptibility weight-imaging (SWI). Objective: To evaluate the SWI sequence using 3T MRI for the detection of CMB, and its ability to differentiate elderly control subjects (CS), stable mild cognitive impairment patients (MCI-s), MCI patients progressing to AD (MCI-p), and AD patients. Methods: It was a prospective, monocentric, observational study that took place Toulouse, France. Participants were 65 years and older, enrolled in three groups: CS, MCI, and AD. Based on the longitudinal analysis of cognitive decline, MCI subjects were retrospectively classified as MCI-s or MCI-p. Each patient had a 4-year follow-up with MRI at baseline (MRI#1) and during the fourth year (MRI#3). CMB were counted on native SWI images juxtaposed to minIP reformatted images. Results: 150 patients were enrolled: 48 CS, 25 MCI-s, 18 MCI-p, 59 AD. At MRI#1 and at MRI#3, there was no significant difference in the prevalence of CMB between groups (p=0.75 and p=0.87). In the MCI-p + AD group, significantly more subjects had ≥4 incident CMB compared to the CS + MCI-s group (p=0.016). In the MCI-p + AD group, the prevalence of patients with >4 CMB was significantly higher at MRI#3 than at MRI#1 (p=0.008). Conclusion: Using SWI, AD and MCI-p patients had developed significantly more new CMB than CS and MCI-s patients during the follow-up. Incident CMB might be suggested as a potential imaging marker of AD progression.
Tomoyuki Nagata, Shinichiro Nakajima, Shunichiro Shinagawa, Eric Plitman, Kazuhiko Nakayama, Ariel Graff-Guerrero, Masaru Mimura
Baseline Predictors of Antipsychotic Treatment Continuation and Response at Week 8 in Patients with Alzheimer’s Disease with Psychosis or Aggressive Symptoms: An Analysis of the CATIE-AD Study
Abstract: Background/Objective: The aim of the present study was to investigate predictors of atypical antipsychotic (AAP) treatment continuation and response by week 8 in patients with Alzheimer's disease (AD) who have psychotic/aggressive symptoms using the Clinical Antipsychotic Trials of Intervention Effectiveness–Alzheimer's Disease (CATIE-AD) dataset. Methods: Clinical data was utilized from 421 AD outpatients with psychotic/aggressive symptoms who needed interventional treatment. Logistic regression analyses were performed to examine which baseline sociodemographic and clinical characteristics contributed to treatment ‘continuation' and ‘response', the latter of which was evaluated by the Clinical Global Impression of Change (CGI-C), Neuropsychiatric Inventory (NPI), and Brief Psychiatric Scale (BPRS). Results: The treatment continuation rate was 48.7%, and CGI-C, NPI, and BPRS response rate by the last observation carried forward method were 42.7%, 48.6%, and 37.5%, respectively. No significant predictor was identified for treatment continuation in the Caucasian patients (n = 331), while better treatment response was predicted by a lower Mini-Mental State Examination score, treatment with risperidone (versus olanzapine and quetiapine), history of diabetes mellitus, healthier physical status, and more severe initial psychotic symptoms. Conclusions: Comparatively high intolerability from AAPs in the short term was confirmed. We found that baseline clinical predictors to treatment response in Caucasian AD patients with psychotic/aggressive symptoms include treatment with risperidone (versus quetiapine and olanzapine), diabetes mellitus, global physical status, cognitive impairment, and psychotic symptoms. Going forward, these findings may help to determine treatment strategies or care plans.
Aikaterini Oikonomidi, Domilė Tautvydaitė, Mehdi M. Gholamrezaee, Hugues Henry, Michael Bacher, Julius Popp
Macrophage Migration Inhibitory Factor is Associated with Biomarkers of Alzheimer’s Disease Pathology and Predicts Cognitive Decline in Mild Cognitive Impairment and Mild Dementia
Abstract: Background: Macrophage migration inhibitory factor (MIF) is a pro-inflammatory protein playing a regulatory role in the immune response. First evidence from in vitro and animal studies suggests that MIF may be involved in the development of Alzheimer’s disease (AD) pathology. Objective: To address in older subjects (i) the relationships between AD pathology and MIF plasma and cerebrospinal fluid (CSF) levels; and (ii) to investigate whether increased MIF-related systemic and CNS inflammation is associated with clinical disease progression. Methods: CSF and plasma concentrations of MIF as well as biomarkers of amyloid, neuronal injury, and tau hyperphosphorylation (CSF Aβ1-42, tau, and ptau, respectively) were assessed in 97 subjects with MCI or mild dementia (cognitive impairment, CI) and 52 healthy volunteers with normal cognition. Clinical and neuropsychological evaluations were performed at inclusion and at follow up visits. Results: CSF MIF levels were higher in participants with CI with an AD CSF biomarker profile, but not in CI with a non-AD profile, compared to the healthy controls. Higher MIF CSF levels were associated with higher CSF tau and ptau and lower CSF Aβ1-42 after adjusting for potential confounders. In CI, MIF CSF independently predicted cognitive decline at a follow-up visit after controlling for potential confounders including CSF Aβ1-42 and tau levels. Conclusion: Our study provides evidence that MIF-related inflammation is related to amyloid pathology, tau hyperphosphorylation, and neuronal injury at the early clinical stages of AD. Higher MIF CSF levels are associated with accelerated cognitive decline in MCI and mild dementia.
Ivan Koychev, Roger N. Gunn, Azadeh Firouzian, Jennifer Lawson, Giovanna Zamboni, Basil Ridha, Barbara J. Sahakian, James B. Rowe, Alan Thomas, Lynn Rochester, Dominic ffytche, Robert Howard, Henrik Zetterberg, Clare MacKay, Simon Lovestone on behalf of the Deep and Frequent Phenotyping study team
PET Tau and Amyloid-β Burden in Mild Alzheimer’s Disease: Divergent Relationship with Age, Cognition, and Cerebrospinal Fluid Biomarkers
Abstract: Background: Combining PET amyloid-β (Aβ) and tau imaging may be critical for tracking disease progression in Alzheimer’s disease (AD). Objective: We sought to characterize the relationship between Aβ and tau ligands as well as with other measures of pathology. Methods: We conducted a multi-center observational study in early AD (MMSE > 20) participants aged 50 to 85 y. The schedule included cognitive assessments (ADAS-Cog) and CSF measurement of Aβ and tau at baseline and 6 months; PET-CT imaging with Aβ ([18F]AV45) and tau ([18F]AV1451) ligands at baseline. Results: 22 participants took part in the study with 20 completing its 6-month duration and 12 having both tau and amyloid PET. The PET biomarker analysis revealed a strong negative correlation between age and tau in multiple regions. Entorhinal cortex tau and age interacted significantly in terms of cognitive change over 6 months which may have been to older participants deteriorating faster despite lower levels of cortical tau. Cortical Aβ associated with entorhinal cortex tau while CSF tau/Aβ ratio correlated strongly with cortical tau but not Aβ. Conclusion: The negative relationship between age and cortical tau whereby younger patients with mild AD had relatively greater tau burden is potentially important. It suggests that younger-age onset AD may be primarily driven by tau pathology while AD developing later may depend on a multitude of pathological mechanisms. These data also suggest that PET-tau performs better than PET-amyloid in predicting the best validated AD diagnostic marker—the CSF total tau/Aβ ratio.
Iman Beheshti, Norihide Maikusa, Morteza Daneshmand, Hiroshi Matsuda, Hasan Demirel, Gholamreza Anbarjafari, for the Japanese-Alzheimer’s Disease Neuroimaging Initiative
Classification of Alzheimer’s Disease and Prediction of Mild Cognitive Impairment Conversion Using Histogram-Based Analysis of Patient-Specific Anatomical Brain Connectivity Networks
Abstract: In this study, we investigated the early detection of Alzheimer’s disease (AD) and mild cognitive impairment (MCI) conversion to AD through individual structural connectivity networks using structural magnetic resonance imaging (sMRI) data. In the proposed method, the cortical morphometry of individual gray matter images were used to construct structural connectivity networks. A statistical feature generation approach based on histogram-based feature generation procedure was proposed to represent a statistical-pattern of connectivity networks from a high-dimensional space into low-dimensional feature vectors. The proposed method was evaluated on numerous samples including 61 healthy controls (HC), 42 stable-MCI (sMCI), 45 progressive-MCI (pMCI), and 83 AD subjects at the baseline from the J-ADNI data-set using support vector machine classifier. The proposed method yielded a classification accuracy of 84.17%, 70.38%, and 61.05% in identifying AD/HC, MCIs/HCs, and sMCI/pMCI, respectively. The experimental results show that the proposed method performed in a comparable way to alternative methods using MRI data.
Elisabeth Nikitidou, Payam Emami Khoonsari, Ganna Shevchenko, Martin Ingelsson, Kim Kultima, Anna Erlandsson
Increased Release of Apolipoprotein E in Extracellular Vesicles Following Amyloid-β Protofibril Exposure of Neuroglial Co-Cultures
Abstract: Extracellular vesicles (EVs), including exosomes and larger microvesicles, have been implicated to play a role in several conditions, including Alzheimer’s disease (AD). Since the EV content mirrors the intracellular environment, it could contribute with important information about ongoing pathological processes and may be a useful source for biomarkers, reflecting the disease progression. The aim of the present study was to analyze the protein content of EVs specifically released from a mixed co-culture of primary astrocytes, neurons, and oligodendrocytes treated with synthetic amyloid-β (Aβ42) protofibrils. The EV isolation was performed by ultracentrifugation and validated by transmission electron microscopy. Mass spectrometry analysis of the EV content revealed a total of 807 unique proteins, of which five displayed altered levels in Aβ42 protofibril exposed cultures. The most prominent protein was apolipoprotein E (apoE), and by western blot analysis we could confirm a threefold increase of apoE in EVs from Aβ42 protofibril exposed cells, compared to unexposed cells. Moreover, immunoprecipitation studies demonstrated that apoE was primarily situated inside the EVs, whereas immunocytochemistry indicated that the EVs most likely derived from the astrocytes and the neurons in the culture. The identified Aβ-induced sorting of apoE into EVs from cultured neuroglial cells suggests a possible role for intercellular transfer of apoE in AD pathology and encourage future studies to fully elucidate the clinical relevance of this event.
Annika Toots, Håkan Littbrand, Gustaf Boström, Carl Hörnsten, Henrik Holmberg, Lillemor Lundin-Olsson, Nina Lindelöf, Peter Nordström, Yngve Gustafson, Erik Rosendahl
Effects of Exercise on Cognitive Function in Older People with Dementia: A Randomized Controlled Trial
Abstract: Background: Although physical exercise has been suggested to influence cognitive function, previous exercise studies show inconsistent results in people with dementia. Objectives: To investigate effects of exercise on cognitive function in people with dementia. Method: The Umeå Dementia and Exercise (UMDEX) study, a cluster-randomized controlled trial, was set in 16 nursing homes in Umeå, Sweden. One hundred-and-forty-one women and 45 men with dementia; mean age of 85 y and mean Mini-Mental State Examination (MMSE) score of 15, were randomized to a High-Intensity Functional Exercise program or a seated attention control activity. Blinded assessors measured global cognitive function using the MMSE and the Alzheimer’s disease Assessment Scale – Cognitive subscale (ADAS-Cog), and executive function using Verbal fluency (VF) at baseline and 4 months (directly after intervention completion), and MMSE and VF at 7 months. Results: Linear mixed models showed no between-group effects in mean difference from baseline (95% confidence intervals, CI) at 4 months in MMSE (–0.27; 95% CI –1.4 to 0.87, p = 0.644), ADAS-Cog (–1.04, 95% CI –4 to 1.92, p = 0.491), or VF (–0.53, 95% CI –1.42 to 0.35, p = 0.241) or at 7 months in MMSE (–1.15, 95% CI –2.32 to 0.03, p = 0.056) or VF (–0.18, 95%CI –1.09 to 0.74, p = 0.707). Conclusion: A 4-month, high-intensity functional exercise program had no superior effects on global cognition or executive function in people with dementia living in nursing homes when compared with an attention control activity.