%0 Journal Article %J J Alzheimers Dis %D 2022 %T Comparative Analysis of Alzheimer's Disease Cerebrospinal Fluid Biomarkers Measurement by Multiplex SOMAscan Platform and Immunoassay-Based Approach. %A Timsina, Jigyasha %A Gomez-Fonseca, Duber %A Wang, Lihua %A Do, Anh %A Western, Dan %A Álvarez, Ignacio %A Aguilar, Miquel %A Pastor, Pau %A Henson, Rachel L %A Herries, Elizabeth %A Xiong, Chengjie %A Schindler, Suzanne E %A Fagan, Anne M %A Bateman, Randall J %A Farlow, Martin %A Morris, John C %A Perrin, Richard %A Moulder, Krista %A Hassenstab, Jason %A Chhatwal, Jasmeer %A Mori, Hiroshi %A Sung, Yun Ju %A Cruchaga, Carlos %X

BACKGROUND: The SOMAscan assay has an advantage over immunoassay-based methods because it measures a large number of proteins in a cost-effective manner. However, the performance of this technology compared to the routinely used immunoassay techniques needs to be evaluated.

OBJECTIVE: We performed comparative analyses of SOMAscan and immunoassay-based protein measurements for five cerebrospinal fluid (CSF) proteins associated with Alzheimer's disease (AD) and neurodegeneration: NfL, Neurogranin, sTREM2, VILIP-1, and SNAP-25.

METHODS: We compared biomarkers measured in ADNI (N = 689), Knight-ADRC (N = 870), DIAN (N = 115), and Barcelona-1 (N = 92) cohorts. Raw protein values were transformed using z-score in order to combine measures from the different studies. sTREM2 and VILIP-1 had more than one analyte in SOMAscan; all available analytes were evaluated. Pearson's correlation coefficients between SOMAscan and immunoassays were calculated. Receiver operating characteristic curve and area under the curve were used to compare prediction accuracy of these biomarkers between the two platforms.

RESULTS: Neurogranin, VILIP-1, and NfL showed high correlation between SOMAscan and immunoassay measures (r >  0.9). sTREM2 had a fair correlation (r >  0.6), whereas SNAP-25 showed weak correlation (r = 0.06). Measures in both platforms provided similar predicted performance for all biomarkers except SNAP-25 and one of the sTREM2 analytes. sTREM2 showed higher AUC for SOMAscan based measures.

CONCLUSION: Our data indicate that SOMAscan performs as well as immunoassay approaches for NfL, Neurogranin, VILIP-1, and sTREM2. Our study shows promise for using SOMAscan as an alternative to traditional immunoassay-based measures. Follow-up investigation will be required for SNAP-25 and additional established biomarkers.

%B J Alzheimers Dis %V 89 %P 193-207 %8 2022 Aug 30 %G eng %N 1 %R 10.3233/JAD-220399 %0 Journal Article %J J Alzheimers Dis %D 2022 %T Sex-Specific Patterns of Body Mass Index Relationship with White Matter Connectivity. %A Rahmani, Farzaneh %A Wang, Qing %A McKay, Nicole S %A Keefe, Sarah %A Hantler, Nancy %A Hornbeck, Russ %A Wang, Yong %A Hassenstab, Jason %A Schindler, Suzanne %A Xiong, Chengjie %A Morris, John C %A Benzinger, Tammie L S %A Raji, Cyrus A %X

BACKGROUND: Obesity is an increasingly recognized modifiable risk factor for Alzheimer's disease (AD). Increased body mass index (BMI) is related to distinct changes in white matter (WM) fiber density and connectivity.

OBJECTIVE: We investigated whether sex differentially affects the relationship between BMI and WM structural connectivity.

METHODS: A cross-sectional sample of 231 cognitively normal participants were enrolled from the Knight Alzheimer Disease Research Center. Connectome analyses were done with diffusion data reconstructed using q-space diffeomorphic reconstruction to obtain the spin distribution function and tracts were selected using a deterministic fiber tracking algorithm.

RESULTS: We identified an inverse relationship between higher BMI and lower connectivity in the associational fibers of the temporal lobe in overweight and obese men. Normal to overweight women showed a significant positive association between BMI and connectivity in a wide array of WM fibers, an association that reversed in obese and morbidly obese women. Interaction analyses revealed that with increasing BMI, women showed higher WM connectivity in the bilateral frontoparietal and parahippocampal parts of the cingulum, while men showed lower connectivity in right sided corticostriatal and corticopontine tracts. Subgroup analyses demonstrated comparable results in participants with and without positron emission tomography or cerebrospinal fluid evidence of brain amyloidosis, indicating that the relationship between BMI and structural connectivity in men and women is independent of AD biomarker status.

CONCLUSION: BMI influences structural connectivity of WM differently in men and women across BMI categories and this relationship does not vary as a function of preclinical AD.

%B J Alzheimers Dis %V 86 %P 1831-1848 %8 2022 Apr 19 %G eng %N 4 %R 10.3233/JAD-215329 %0 Journal Article %J J Alzheimers Dis %D 2020 %T Falls Associate with Neurodegenerative Changes in ATN Framework of Alzheimer's Disease. %A Keleman, Audrey %A Wisch, Julie K %A Bollinger, Rebecca M %A Grant, Elizabeth A %A Benzinger, Tammie L %A Morris, John C %A Ances, Beau M %A Stark, Susan L %X

BACKGROUND: Behavioral markers for Alzheimer's disease (AD) are not included within the widely used amyloid-tau-neurodegeneration framework.

OBJECTIVE: To determine when falls occur among cognitively normal (CN) individuals with and without preclinical AD.

METHODS: This cross-sectional study recorded falls among CN participants (n = 83) over a 1-year period. Tailored calendar journals recorded falls. Biomarkers including amyloid positron emission tomography (PET) and structural and functional magnetic resonance imaging were acquired within 2 years of fall evaluations. CN participants were dichotomized by amyloid PET (using standard cutoffs). Differences in amyloid accumulation, global resting state functional connectivity (rs-fc) intra-network signature, and hippocampal volume were compared between individuals who did and did not fall using Wilcoxon rank sum tests. Among preclinical AD participants (amyloid-positive), the partial correlation between amyloid accumulation and global rs-fc intra-network signature was compared for those who did and did not fall.

RESULTS: Participants who fell had smaller hippocampal volumes (p = 0.04). Among preclinical AD participants, those who fell had a negative correlation between amyloid uptake and global rs-fc intra-network signature (R = -0.75, p = 0.012). A trend level positive correlation was observed between amyloid uptake and global rs-fc intra-network signature (R = 0.70, p = 0.081) for preclinical AD participants who did not fall.

CONCLUSION: Falls in CN older adults correlate with neurodegeneration biomarkers. Participants without falls had lower amyloid deposition and preserved global rs-fc intra-network signature. Falls most strongly correlated with presence of amyloid and loss of brain connectivity and occurred in later stages of preclinical AD.

%B J Alzheimers Dis %V 77 %P 843-853 %8 2020 Sep 15 %G eng %N 2 %R 10.3233/JAD-200192 %0 Journal Article %J J Alzheimers Dis %D 2019 %T Higher Body Mass Index Is Associated with Lower Cortical Amyloid-β Burden in Cognitively Normal Individuals in Late-Life. %A Thirunavu, Vineeth %A McCullough, Austin %A Su, Yi %A Flores, Shaney %A Dincer, Aylin %A Morris, John C %A Cruchaga, Carlos %A Benzinger, Tammie L S %A Gordon, Brian A %X

BACKGROUND: Both low and high body mass index (BMI) have been associated with an increased risk of dementia, including that caused by Alzheimer's disease (AD). Specifically, high middle-age BMI or a low late-age BMI has been considered a predictor for the development of AD dementia. Less studied is the relationship between BMI and AD pathology.

OBJECTIVE: We explored the association between BMI and cortical amyloid-β (Aβ) burden in cognitively normal participants that were either in mid-life (45-60 years) or late-life (>60).

METHODS: We analyzed cross-sectional baseline data from the Knight Alzheimer Disease Research Center (ADRC) at Washington University. Aβ pathology was measured in 373 individuals with Aβ PET imaging and was quantified using Centiloid units. We split the cohort into mid- and late-life groups for analyses (n = 96 and n = 277, respectively). We ran general linear regression models to predict Aβ levels from BMI while controlling for age, sex, years of education, and APOE4 status. Analyses were also conducted to test the interaction between BMI and APOE4 genotype and between BMI and sex.

RESULTS: Higher BMI was associated with lower cortical Aβ burden in late-life (β= -0.81, p = 0.0066), but no relationship was found in mid-life (β= 0.04, p > 0.5). The BMI×APOE4+ and BMI×male interaction terms were not significant in the mid-life (β= 0.28, p = 0.41; β= 0.64, p = 0.13) or the late-life (β= 0.17, p > 0.5; β= 0.50, p = 0.43) groups.

CONCLUSION: Higher late-life BMI is associated with lower cortical Aβ burden in cognitively normal individuals.

%B J Alzheimers Dis %V 69 %P 817-827 %8 2019 Jun 4 %G eng %N 3 %R 10.3233/JAD-190154 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Assessment of the Genetic Architecture of Alzheimer's Disease Risk in Rate of Memory Decline. %A Del-Aguila, Jorge L %A Fernández, Maria Victoria %A Schindler, Suzanne %A Ibanez, Laura %A Deming, Yuetiva %A Ma, Shengmei %A Saef, Ben %A Black, Kathleen %A Budde, John %A Norton, Joanne %A Chasse, Rachel %A Harari, Oscar %A Goate, Alison %A Xiong, Chengjie %A Morris, John C %A Cruchaga, Carlos %K Age of Onset %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Dementia %K Disease Progression %K Female %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Heterozygote %K Humans %K Longitudinal Studies %K Male %K Membrane Glycoproteins %K Memory Disorders %K Middle Aged %K Polymorphism, Single Nucleotide %K Receptors, Immunologic %K Risk Assessment %X

Many genetic studies for Alzheimer's disease (AD) have been focused on the identification of common genetic variants associated with AD risk and not on other aspects of the disease, such as age at onset or rate of dementia progression. There are multiple approaches to untangling the genetic architecture of these phenotypes. We hypothesized that the genetic architecture of rate of progression is different than the risk for developing AD dementia. To test this hypothesis, we used longitudinal clinical data from ADNI and the Knight-ADRC at Washington University, and we calculated PRS (polygenic risk score) based on the IGAP study to compare the genetic architecture of AD risk and dementia progression. Dementia progression was measured by the change of Clinical Dementia Rating Sum of Boxes (CDR)-SB per year. Out of the 21 loci for AD risk, no association with the rate of dementia progression was found. The PRS rate was significantly associated with the rate of dementia progression (β= 0.146, p = 0.03). In the case of rare variants, TREM2 (β= 0.309, p = 0.02) was also associated with the rate of dementia progression. TREM2 variant carriers showed a 23% faster rate of dementia compared with non-variant carriers. In conclusion, our results indicate that the recently identified common and rare variants for AD susceptibility have a limited impact on the rate of dementia progression in AD patients.

%B J Alzheimers Dis %V 62 %P 745-756 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29480181?dopt=Abstract %R 10.3233/JAD-170834 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Depression and Alzheimer's Disease Biomarkers Predict Driving Decline. %A Babulal, Ganesh M %A Chen, Suzie %A Williams, Monique M %A Trani, Jean-Francois %A Bakhshi, Parul %A Chao, Grace L %A Stout, Sarah H %A Fagan, Anne M %A Benzinger, Tammie L S %A Holtzman, David M %A Morris, John C %A Roe, Catherine M %X

BACKGROUND: Symptomatic Alzheimer's disease (AD) and depression independently increase crash risk. Additionally, depression is both a risk factor for and a consequence of AD.

OBJECTIVE: To examine whether a depression diagnosis, antidepressant use, and preclinical AD are associated with driving decline among cognitively normal older adults.

METHODS: Cognitively normal participants, age ≥65, were enrolled. Cox proportional hazards models evaluated whether a depression diagnosis, depressive symptoms (Geriatric Depression Scale), antidepressant use, cerebrospinal fluid (amyloid-β42 [Aβ42], tau, phosphorylated tau181 [ptau181]), and amyloid imaging biomarkers (Pittsburgh Compound B and Florbetapir) were associated with time to receiving a rating of marginal/fail on a road test. Age was adjusted for in all models.

RESULTS: Data were available from 131 participants with age ranging from 65.4 to 88.2 years and mean follow up of 2.4 years (SD = 1.0). A depression diagnosis was associated with a faster time to receiving a marginal/fail rating on a road test and antidepressant use (p = 0.024, HR = 2.62). Depression diagnosis and CSF and amyloid PET imaging biomarkers were associated with driving performance on the road test (p≤0.05, HR = 2.51-3.15). In the CSF ptau181 model, depression diagnosis (p = 0.031, HR = 2.51) and antidepressant use (p = 0.037, HR = 2.50) were statistically significant predictors. There were no interaction effects between depression diagnosis, antidepressant use, and biomarker groups. Depressive symptomology was not a statistically significant predictor of driving performance.

CONCLUSIONS: While, as previously shown, preclinical AD alone predicts a faster time to receiving a marginal/fail rating, these results suggest that also having a diagnosis of depression accelerates the onset of driving problems in cognitively normal older adults.

%B J Alzheimers Dis %V 66 %P 1213-1221 %8 2018 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/30400098?dopt=Abstract %R 10.3233/JAD-180564 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Tau and Amyloid Positron Emission Tomography Imaging Predict Driving Performance Among Older Adults with and without Preclinical Alzheimer's Disease. %A Roe, Catherine M %A Babulal, Ganesh M %A Mishra, Shruti %A Gordon, Brian A %A Stout, Sarah H %A Ott, Brian R %A Carr, David B %A Ances, Beau M %A Morris, John C %A Benzinger, Tammie L S %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Amyloid %K Automobile Driving %K Biomarkers %K Carbolines %K Female %K Humans %K Logistic Models %K Male %K Neuroimaging %K Positron-Emission Tomography %K tau Proteins %X

Abnormal levels of Alzheimer's disease (AD) biomarkers, measured by positron emission tomography imaging using amyloid-based radiotracers and cerebrospinal fluid, are associated with impaired driving performance in older adults. We examined whether preclinical AD staging, defined using amyloid imaging and tau imaging using the radiotracer T807 (AKA flortaucipir or AV-1451), was associated with receiving a marginal/fail rating on a standardized road test (n = 42). Participants at Stage 2 (positive amyloid and tau scans) of preclinical AD were more likely to receive a marginal/fail rating compared to participants at Stage 0 or 1. Stage 2 preclinical AD may manifest in worse driving performance.

%B J Alzheimers Dis %V 61 %P 509-513 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29171997?dopt=Abstract %R 10.3233/JAD-170521 %0 Journal Article %J J Alzheimers Dis %D 2017 %T Cerebrospinal Fluid Aβ42/40 Corresponds Better than Aβ42 to Amyloid PET in Alzheimer's Disease. %A Lewczuk, Piotr %A Matzen, Anja %A Blennow, Kaj %A Parnetti, Lucilla %A Molinuevo, José Luis %A Eusebi, Paolo %A Kornhuber, Johannes %A Morris, John C %A Fagan, Anne M %X

BACKGROUND: Decreased concentrations of amyloid-β 1-42 (Aβ42) in cerebrospinal fluid (CSF) and increased retention of Aβ tracers in the brain on positron emission tomography (PET) are considered the earliest biomarkers of Alzheimer's disease (AD). However, a proportion of cases show discrepancies between the results of the two biomarker modalities which may reflect inter-individual differences in Aβ metabolism. The CSF Aβ42/40 ratio seems to be a more accurate biomarker of clinical AD than CSF Aβ42 alone.

OBJECTIVE: We tested whether CSF Aβ42 alone or the Aβ42/40 ratio corresponds better with amyloid PET status and analyzed the distribution of cases with discordant CSF-PET results.

METHODS: CSF obtained from a mixed cohort (n = 200) of cognitively normal and abnormal research participants who had undergone amyloid PET within 12 months (n = 150 PET-negative, n = 50 PET-positive according to a previously published cut-off) was assayed for Aβ42 and Aβ40 using two recently developed immunoassays. Optimal CSF cut-offs for amyloid positivity were calculated, and concordance was tested by comparison of the areas under receiver operating characteristic (ROC) curves (AUC) and McNemar's test for paired proportions.

RESULTS: CSF Aβ42/40 corresponded better than Aβ42 with PET results, with a larger proportion of concordant cases (89.4% versus 74.9%, respectively, p < 0.0001) and a larger AUC (0.936 versus 0.814, respectively, p < 0.0001) associated with the ratio. For both CSF biomarkers, the percentage of CSF-abnormal/PET-normal cases was larger than that of CSF-normal/PET-abnormal cases.

CONCLUSION: The CSF Aβ42/40 ratio is superior to Aβ42 alone as a marker of amyloid-positivity by PET. We hypothesize that this increase in performance reflects the ratio compensating for general between-individual variations in CSF total Aβ.

%B J Alzheimers Dis %V 55 %P 813-822 %G ENG %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/27792012?dopt=Abstract %R 10.3233/JAD-160722 %0 Journal Article %J J Alzheimers Dis %D 2017 %T Neuropsychiatric Symptoms and Alzheimer's Disease Biomarkers Predict Driving Decline: Brief Report. %A Babulal, Ganesh M %A Stout, Sarah H %A Head, Denise %A Holtzman, David M %A Fagan, Anne M %A Morris, John C %A Roe, Catherine M %X

We examined whether neuropsychiatric symptoms (NPS) interact with cerebrospinal fluid (CSF) biomarkers (amyloid-β42 [Aβ42], tau, phosphorylated tau181 [ptau181], tau/Aβ42, and ptau181/Aβ42) of Alzheimer's disease pathology to predict driving decline among cognitively-normal older adults (N = 116) aged ≥65. Cox proportional hazards models examined time to receiving a rating of marginal or fail on the driving test. Age, education, and gender were adjusted in the models. Participants with more abnormal CSF (Aβ42, tau/Aβ42, ptau181/Aβ42) and NPS were faster to receive a marginal/fail on the road test compared to those without NPS. NPS interact with abnormal CSF biomarkers to impact driving performance among cognitively-normal older adults.

%B J Alzheimers Dis %V 58 %P 675-680 %8 2017 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/28453487?dopt=Abstract %R 10.3233/JAD-170067 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Cerebrospinal Fluid Biomarkers and Reserve Variables as Predictors of Future "Non-Cognitive" Outcomes of Alzheimer's Disease. %A Ingber, Adam P %A Hassenstab, Jason %A Fagan, Anne M %A Benzinger, Tammie L S %A Grant, Elizabeth A %A Holtzman, David M %A Morris, John C %A Roe, Catherine M %X

BACKGROUND: The influence of reserve variables and Alzheimer's disease (AD) biomarkers on cognitive test performance has been fairly well-characterized. However, less is known about the influence of these factors on "non-cognitive" outcomes, including functional abilities and mood.

OBJECTIVE: We examined whether cognitive and brain reserve variables mediate how AD biomarker levels in cognitively normal persons predict future changes in function, mood, and neuropsychiatric behavior.

METHODS: Non-cognitive outcomes were examined in 328 individuals 50 years and older enrolled in ongoing studies of aging and dementia at the Knight Alzheimer Disease Research Center (ADRC). All participants were cognitively normal at baseline (Clinical Dementia Rating [CDR] 0), completed cerebrospinal fluid (CSF) and structural neuroimaging studies within one year of baseline, and were followed for an average of 4.6 annual visits. Linear mixed effects models explored how cognitive reserve and brain reserve variables mediate the relationships between AD biomarker levels and changes in function, mood, and neuropsychiatric behavior in cognitively normal participants.

RESULTS: Education levels did not have a significant effect on predicting non-cognitive decline. However, participants with smaller brain volumes exhibited the worst outcomes on measures of mood, functional abilities, and behavioral disturbance. This effect was most pronounced in individuals who also had abnormal CSF biomarkers.

CONCLUSIONS: The findings suggest that brain reserve plays a stronger, or earlier, role than cognitive reserve in protecting against non-cognitive impairment in AD.

%B J Alzheimers Dis %V 52 %P 1055-64 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/27104893?dopt=Abstract %R 10.3233/JAD-150478 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Plasma Phospholipid and Sphingolipid Alterations in Presenilin1 Mutation Carriers: A Pilot Study. %A Chatterjee, Pratishtha %A Lim, Wei L F %A Shui, Guanghou %A Gupta, Veer B %A James, Ian %A Fagan, Anne M %A Xiong, Chengjie %A Sohrabi, Hamid R %A Taddei, Kevin %A Brown, Belinda M %A Benzinger, Tammie %A Masters, Colin %A Snowden, Stuart G %A Wenk, Marcus R %A Bateman, Randall J %A Morris, John C %A Martins, Ralph N %K Adult %K Alzheimer Disease %K Apolipoproteins E %K Female %K Humans %K Linear Models %K Male %K Middle Aged %K Mutation %K Phospholipids %K Pilot Projects %K Presenilin-1 %K Sphingolipids %X

BACKGROUND AND OBJECTIVE: Aberrant lipid metabolism has been implicated in sporadic Alzheimer's disease (AD). The current study investigated plasma phospholipid and sphingolipid profiles in individuals carrying PSEN1 mutations responsible for autosomal dominant AD (ADAD).

METHODS: Study participants evaluated were from the Perth and Melbourne sites of the Dominantly Inherited Alzheimer Network (DIAN) study. Plasma phospholipid and sphingolipid profiles were measured using liquid chromatography coupled with mass spectrometry in 20 PSEN1 mutation carriers (MC; eight of whom were symptomatic and twelve asymptomatic, based on Clinical Dementia Rating scores) and compared with six non carriers (NC) using linear mixed models. Further, AD gold standard biomarker data obtained from the DIAN database were correlated with lipid species significantly altered between MC and NC, using Spearman's correlation coefficient.

RESULTS: One-hundred and thirty-nine plasma phospholipid and sphingolipid species were measured. Significantly altered species in MC compared to NC primarily belonged to choline and ethanolamine containing phospholipid classes and ceramides. Further phosphatidylcholine species (34:6, 36:5, 40:6) correlated with cerebrospinal fluid tau (p <  0.05), and plasmalogen ethanolamine species (34:2, 36:,4) correlated with both cerebrospinal fluid tau and brain amyloid load within the MC group (p <  0.05).

CONCLUSION: These findings indicate altered phospholipid and sphingolipid metabolism in ADAD and provide insight into the pathomolecular changes occurring with ADAD pathogenesis. Further, findings reported in this study allow comparison of lipid alterations in ADAD with those reported previously in sporadic AD. The findings observed in the current pilot study warrant validation in the larger DIAN cohort.

%B J Alzheimers Dis %V 50 %P 887-94 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26836186?dopt=Abstract %R 10.3233/JAD-150948 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Spatial Navigation in Preclinical Alzheimer's Disease. %A Allison, Samantha L %A Fagan, Anne M %A Morris, John C %A Head, Denise %K Aged %K Alzheimer Disease %K Biomarkers %K Educational Status %K Female %K Humans %K Learning %K Male %K Neuropsychological Tests %K Prodromal Symptoms %K Psychomotor Performance %K ROC Curve %K Spatial Navigation %K tau Proteins %K User-Computer Interface %X

Although several previous studies have demonstrated navigational deficits in early-stage symptomatic Alzheimer's disease (AD), navigational abilities in preclinical AD have not been examined. The present investigation examined the effects of preclinical AD and early-stage symptomatic AD on spatial navigation performance. Performance on tasks of wayfinding and route learning in a virtual reality environment were examined. Comparisons were made across the following three groups: Clinically normal without preclinical AD (n = 42), clinically normal with preclinical AD (n = 13), and early-stage symptomatic AD (n = 16) groups. Preclinical AD was defined based on cerebrospinal fluid Aβ42 levels below 500 pg/ml. Preclinical AD was associated with deficits in the use of a wayfinding strategy, but not a route learning strategy. Moreover, post-hoc analyses indicated that wayfinding performance had moderate sensitivity and specificity. Results also confirmed early-stage symptomatic AD-related deficits in the use of both wayfinding and route learning strategies. The results of this study suggest that aspects of spatial navigation may be particularly sensitive at detecting the earliest cognitive deficits of AD.

%B J Alzheimers Dis %V 52 %P 77-90 %8 2016 02 09 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26967209?dopt=Abstract %R 10.3233/JAD-150855 %0 Journal Article %J Arch Neurol %D 2012 %T Exercise Engagement as a Moderator of the Effects of APOE Genotype on Amyloid Deposition. %A Head, Denise %A Bugg, Julie M %A Goate, Alison M %A Fagan, Anne M %A Mintun, Mark A %A Benzinger, Tammie %A Holtzman, David M %A Morris, John C %K Aged %K Aged, 80 and over %K Amyloid beta-Peptides %K Aniline Compounds %K Apolipoprotein E4 %K Brain %K Cognition %K Cohort Studies %K Exercise %K Female %K Genetic Association Studies %K Genotype %K Humans %K Male %K Middle Aged %K Neuropsychological Tests %K Peptide Fragments %K Positron-Emission Tomography %K Regression Analysis %K Surveys and Questionnaires %K Thiazoles %X

OBJECTIVE: APOE ε4 status has been associated with greater cortical amyloid deposition, whereas exercise has been associated with less in cognitively normal adults. The primary objective here was to examine whether physical exercise moderates the association between APOE genotype and amyloid deposition in cognitively normal adults.

DESIGN: APOE genotyping data and answers to a questionnaire on physical exercise engagement over the last decade were obtained in conjunction with cerebrospinal fluid (CSF) samples and amyloid imaging with carbon 11-labeled Pittsburgh Compound B ([(11)C]PiB) positron emission tomography. Participants were classified as either low or high exercisers based on exercise guidelines of the American Heart Association.

SETTING: Knight Alzheimer's Disease Research Center at Washington University, St Louis, Missouri.

PARTICIPANTS: A total of 201 cognitively normal adults (135 of whom were women) aged 45 to 88 years were recruited from the Knight Alzheimer's Disease Research Center. Samples of CSF were collected from 165 participants. Amyloid imaging was performed for 163 participants.

RESULTS: APOE ε4 carriers evidenced higher [(11)C]PiB binding (P<.001) and lower CSF Aβ42 levels (P<.001) than did noncarriers. Our previous findings of higher [(11)C]PiB binding (P=.005) and lower CSF Aβ42 levels (P=.009) in more sedentary individuals were replicated. Most importantly, we observed a novel interaction between APOE status and exercise engagement for [(11)C]PiB binding (P=.008) such that a more sedentary lifestyle was significantly associated with higher [(11)C]PiB binding for ε4 carriers (P=.013) but not for noncarriers (P=.20). All findings remained significant after controlling for age; sex; educational level; body mass index; the presence or history of hypertension, diabetes mellitus, heart problems, or depression; and the interval between assessments.

CONCLUSION: Collectively, these results suggest that cognitively normal sedentary APOE ε4-positive individuals may be at augmented risk for cerebral amyloid deposition.

%B Arch Neurol %V 69 %P 636-43 %8 2012 May %G eng %N 5 %1 http://www.ncbi.nlm.nih.gov/pubmed/22232206?dopt=Abstract %R 10.1001/archneurol.2011.845 %0 Journal Article %J Alzheimers Dement %D 2011 %T The diagnosis of dementia due to Alzheimer's disease: recommendations from the National Institute on Aging-Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease. %A McKhann, Guy M %A Knopman, David S %A Chertkow, Howard %A Hyman, Bradley T %A Jack, Clifford R %A Kawas, Claudia H %A Klunk, William E %A Koroshetz, Walter J %A Manly, Jennifer J %A Mayeux, Richard %A Mohs, Richard C %A Morris, John C %A Rossor, Martin N %A Scheltens, Philip %A Carrillo, Maria C %A Thies, Bill %A Weintraub, Sandra %A Phelps, Creighton H %K Alzheimer Disease %K Biomarkers %K Diagnosis, Differential %K Diagnostic Imaging %K Disease Progression %K Humans %K National Institute on Aging (U.S.) %K Practice Guidelines as Topic %K Societies, Medical %K United States %X

The National Institute on Aging and the Alzheimer's Association charged a workgroup with the task of revising the 1984 criteria for Alzheimer's disease (AD) dementia. The workgroup sought to ensure that the revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available. We present criteria for all-cause dementia and for AD dementia. We retained the general framework of probable AD dementia from the 1984 criteria. On the basis of the past 27 years of experience, we made several changes in the clinical criteria for the diagnosis. We also retained the term possible AD dementia, but redefined it in a manner more focused than before. Biomarker evidence was also integrated into the diagnostic formulations for probable and possible AD dementia for use in research settings. The core clinical criteria for AD dementia will continue to be the cornerstone of the diagnosis in clinical practice, but biomarker evidence is expected to enhance the pathophysiological specificity of the diagnosis of AD dementia. Much work lies ahead for validating the biomarker diagnosis of AD dementia.

%B Alzheimers Dement %V 7 %P 263-9 %8 2011 May %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/21514250?dopt=Abstract %R 10.1016/j.jalz.2011.03.005 %0 Journal Article %J Sci Transl Med %D 2011 %T Human apoE isoforms differentially regulate brain amyloid-β peptide clearance. %A Castellano, Joseph M %A Kim, Jungsu %A Stewart, Floy R %A Jiang, Hong %A DeMattos, Ronald B %A Patterson, Bruce W %A Fagan, Anne M %A Morris, John C %A Mawuenyega, Kwasi G %A Cruchaga, Carlos %A Goate, Alison M %A Bales, Kelly R %A Paul, Steven M %A Bateman, Randall J %A Holtzman, David M %K Adult %K Aged %K Alleles %K Alzheimer Disease %K Amyloid beta-Peptides %K Animals %K Apolipoprotein E4 %K Biomarkers %K Brain %K Female %K Genotype %K Humans %K Male %K Mice %K Mice, Inbred C57BL %K Mice, Transgenic %K Microdialysis %K Middle Aged %K Protein Isoforms %X

The apolipoprotein E (APOE) ε4 allele is the strongest genetic risk factor for late-onset, sporadic Alzheimer's disease (AD). The APOE ε4 allele markedly increases AD risk and decreases age of onset, likely through its strong effect on the accumulation of amyloid-β (Aβ) peptide. In contrast, the APOE ε2 allele appears to decrease AD risk. Most rare, early-onset forms of familial AD are caused by autosomal dominant mutations that often lead to overproduction of Aβ(42) peptide. However, the mechanism by which APOE alleles differentially modulate Aβ accumulation in sporadic, late-onset AD is less clear. In a cohort of cognitively normal individuals, we report that reliable molecular and neuroimaging biomarkers of cerebral Aβ deposition vary in an apoE isoform-dependent manner. We hypothesized that human apoE isoforms differentially affect Aβ clearance or synthesis in vivo, resulting in an apoE isoform-dependent pattern of Aβ accumulation later in life. Performing in vivo microdialysis in a mouse model of Aβ-amyloidosis expressing human apoE isoforms (PDAPP/TRE), we find that the concentration and clearance of soluble Aβ in the brain interstitial fluid depends on the isoform of apoE expressed. This pattern parallels the extent of Aβ deposition observed in aged PDAPP/TRE mice. ApoE isoform-dependent differences in soluble Aβ metabolism are observed not only in aged but also in young PDAPP/TRE mice well before the onset of Aβ deposition in amyloid plaques in the brain. Additionally, amyloidogenic processing of amyloid precursor protein and Aβ synthesis, as assessed by in vivo stable isotopic labeling kinetics, do not vary according to apoE isoform in young PDAPP/TRE mice. Our results suggest that APOE alleles contribute to AD risk by differentially regulating clearance of Aβ from the brain, suggesting that Aβ clearance pathways may be useful therapeutic targets for AD prevention.

%B Sci Transl Med %V 3 %P 89ra57 %8 2011 Jun 29 %G eng %N 89 %1 http://www.ncbi.nlm.nih.gov/pubmed/21715678?dopt=Abstract %R 10.1126/scitranslmed.3002156 %0 Journal Article %J Ann Neurol %D 2010 %T APOE predicts amyloid-beta but not tau Alzheimer pathology in cognitively normal aging. %A Morris, John C %A Roe, Catherine M %A Xiong, Chengjie %A Fagan, Anne M %A Goate, Alison M %A Holtzman, David M %A Mintun, Mark A %K Aged %K Aged, 80 and over %K Aging %K Alzheimer Disease %K Amyloid beta-Peptides %K Aniline Compounds %K Apolipoprotein E2 %K Apolipoprotein E4 %K Apolipoproteins E %K Brain %K Female %K Follow-Up Studies %K Genotype %K Humans %K Longitudinal Studies %K Male %K Middle Aged %K Peptide Fragments %K Phosphorylation %K Plaque, Amyloid %K tau Proteins %K Thiazoles %X

OBJECTIVE: To examine interactions of apolipoprotein E (APOE) genotype with age and with in vivo measures of preclinical Alzheimer disease (AD) in cognitively normal aging.

METHODS: Two hundred forty-one cognitively normal individuals, aged 45-88 years, had cerebral amyloid imaging studies with Pittsburgh Compound-B (PIB). Of the 241 individuals, 168 (70%) also had cerebrospinal fluid (CSF) assays of amyloid-beta(42) (Abeta(42)), tau, and phosphorylated tau (ptau(181)). All individuals were genotyped for APOE.

RESULTS: The frequency of individuals with elevated mean cortical binding potential (MCBP) for PIB rose in an age-dependent manner from 0% at ages 45-49 years to 30.3% at 80-88 years. Reduced levels of CSF Abeta(42) appeared to begin earlier (18.2% of those aged 45-49 years) and increase with age in higher frequencies (50% at age 80-88 years) than elevations of MCBP. There was a gene dose effect for the APOE4 genotype, with greater MCBP increases and greater reductions in CSF Abeta(42) with increased numbers of APOE4 alleles. Individuals with an APOE2 allele had no increase in MCBP with age and had higher CSF Abeta(42) levels than individuals without an APOE2 allele. There was no APOE4 or APOE2 effect on CSF tau or ptau(181).

INTERPRETATION: Increasing cerebral Abeta deposition with age is the pathobiological phenotype of APOE4. The biomarker sequence that detects Abeta deposition may first be lowered CSF Abeta(42), followed by elevated MCBP for PIB. A substantial proportion of cognitively normal individuals have presumptive preclinical AD.

%B Ann Neurol %V 67 %P 122-31 %8 2010 Jan %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/20186853?dopt=Abstract %R 10.1002/ana.21843 %0 Journal Article %J PLoS One %D 2010 %T Genetic evidence implicates the immune system and cholesterol metabolism in the aetiology of Alzheimer's disease. %A Jones, Lesley %A Holmans, Peter A %A Hamshere, Marian L %A Harold, Denise %A Moskvina, Valentina %A Ivanov, Dobril %A Pocklington, Andrew %A Abraham, Richard %A Hollingworth, Paul %A Sims, Rebecca %A Gerrish, Amy %A Pahwa, Jaspreet Singh %A Jones, Nicola %A Stretton, Alexandra %A Morgan, Angharad R %A Lovestone, Simon %A Powell, John %A Proitsi, Petroula %A Lupton, Michelle K %A Brayne, Carol %A Rubinsztein, David C %A Gill, Michael %A Lawlor, Brian %A Lynch, Aoibhinn %A Morgan, Kevin %A Brown, Kristelle S %A Passmore, Peter A %A Craig, David %A McGuinness, Bernadette %A Todd, Stephen %A Holmes, Clive %A Mann, David %A Smith, A David %A Love, Seth %A Kehoe, Patrick G %A Mead, Simon %A Fox, Nick %A Rossor, Martin %A Collinge, John %A Maier, Wolfgang %A Jessen, Frank %A Schürmann, Britta %A Heun, Reinhard %A Kölsch, Heike %A van den Bussche, Hendrik %A Heuser, Isabella %A Peters, Oliver %A Kornhuber, Johannes %A Wiltfang, Jens %A Dichgans, Martin %A Frölich, Lutz %A Hampel, Harald %A Hüll, Michael %A Rujescu, Dan %A Goate, Alison M %A Kauwe, John S K %A Cruchaga, Carlos %A Nowotny, Petra %A Morris, John C %A Mayo, Kevin %A Livingston, Gill %A Bass, Nicholas J %A Gurling, Hugh %A McQuillin, Andrew %A Gwilliam, Rhian %A Deloukas, Panos %A Al-Chalabi, Ammar %A Shaw, Christopher E %A Singleton, Andrew B %A Guerreiro, Rita %A Mühleisen, Thomas W %A Nöthen, Markus M %A Moebus, Susanne %A Jöckel, Karl-Heinz %A Klopp, Norman %A Wichmann, H-Erich %A Rüther, Eckhard %A Carrasquillo, Minerva M %A Pankratz, V Shane %A Younkin, Steven G %A Hardy, John %A O'Donovan, Michael C %A Owen, Michael J %A Williams, Julie %K Alzheimer Disease %K Apolipoproteins E %K Cholesterol %K Chromosome Mapping %K Genetic Predisposition to Disease %K Genome, Human %K Genome-Wide Association Study %K Humans %K Immune System %K Polymorphism, Single Nucleotide %X

BACKGROUND: Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes.

METHODOLOGY: We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset.

PRINCIPAL FINDINGS: We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD.

SIGNIFICANCE: Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches.

%B PLoS One %V 5 %P e13950 %8 2010 %G eng %N 11 %1 http://www.ncbi.nlm.nih.gov/pubmed/21085570?dopt=Abstract %R 10.1371/journal.pone.0013950