Journal of Alzheimer's Disease - Volume 86, issue 1

Authors: Sohn, Bo Kyung | Byun, Min Soo | Yi, Dahyun | Jeon, So Yeon | Lee, Jun Ho | Choe, Young Min | Lee, Dong Woo | Lee, Jun-Young | Kim, Yu Kyeong | Sohn, Chul-Ho | Lee, Dong Young | for the KBASE Research Group

Article Type: Research Article

Abstract: Background: Physical activities (PA) have been suggested to reduce the risk of Alzheimer‘s disease (AD) dementia. However, information on the neuropathological links underlying the relationship is limited. Objective: We investigated the role of midlife and late-life PA with in vivo AD neuropathologies in old adults without dementia. Methods: This study included participants from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s disease (KBASE). The participants underwent comprehensive clinical and neuropsychological assessment, [11 C] Pittsburgh Compound B positron emission tomography (PET), [18 F] fluorodeoxyglucose PET, and magnetic resonance imaging. Using the multi-modal …brain imaging data, in vivo AD pathologies including global amyloid deposition, AD-signature region cerebral glucose metabolism (AD-CM), and AD-signature region cortical thickness (AD-CT) were quantified. Both midlife and late-life PA of participants were measured using the Lifetime Total Physical Activity Questionnaire. Results: This study was performed on 260 participants without dementia (195 with normal cognitive function and 65 with mild cognitive impairment). PA of neither midlife nor late-life showed direct correspondence with any neuroimaging biomarker. However, late-life PA moderated the relationship of brain amyloid-β (Aβ) deposition with AD-CM and AD-CT. Aβ positivity had a significant negative effect on both AD-CM and AD-CT in individuals with lower late-life PA, but those with higher late-life PA did not show such results. Midlife PA did not have such a moderation effect. Conclusion: The findings suggest that physically active lifestyle in late-life, rather than that in midlife, may delay AD-associated cognitive decline by decreasing Aβ-induced neurodegenerative changes in old adults. Show more

Keywords: Amyloid, cortical thickness, neurodegeneration, physical activity

DOI: 10.3233/JAD-215258

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 441-450, 2022

Authors: Pedersen, Frederik Nørregaard | Stokholm, Lonny | Pouwer, Frans | Hass Rubin, Katrine | Peto, Tunde | Frydkjær-Olsen, Ulrik | Thykjær, Anne Suhr | Andersen, Nis | Andresen, Jens | Bek, Toke | La Cour, Morten | Heegaard, Steffen | Højlund, Kurt | Kawasaki, Ryo | Hajari, Javad Nouri | Ohm Kyvik, Kirsten | Laugesen, Caroline Schmidt | Schielke, Katja Christina | Simó, Rafael | Grauslund, Jakob

Article Type: Research Article

Abstract: Background: Retinal neurodegeneration is evident in early diabetic retinopathy (DR) which may be associated with other neurodegenerative diseases like Alzheimer's disease (AD). Objective: To investigate diabetes and DR as a risk marker of present and incident AD. Methods: A register-based cohort study was performed. We included 134,327 persons with diabetes above 60 years of age, who had attended DR screening, and 651,936 age- and gender-matched persons without diabetes. Results: At baseline, the prevalence of AD was 0.7% and 1.3% among patients with and without diabetes, respectively. In a multivariable regression model, patients with diabetes …were less likely to have AD at baseline (adjusted OR 0.63, 95% CI 0.59–0.68). During follow-up, incident AD was registered for 1473 (0.35%) and 6,899 (0.34%) persons with and without diabetes, respectively. Compared to persons without diabetes, persons with diabetes and no DR had a lower risk to develop AD (adjusted HR 0.87, 95% CI 0.81–0.93), while persons with diabetes and DR had higher risk of AD (adjusted HR 1.24, 95% CI 1.08–1.43). When persons with diabetes and no DR were used as references, a higher risk of incident AD was observed in persons with DR (adjusted HR 1.34, 95% CI 1.18–1.53). Conclusion: Individuals with diabetes without DR were less likely to develop AD compared to persons without diabetes. However, individuals with DR had a 34% higher risk of incident AD, which raise the question whether screening for cognitive impairment should be done among individuals with DR. Show more

Keywords: Alzheimer’s disease, cognitive impairment, diabetes mellitus, diabetic retinopathy

DOI: 10.3233/JAD-215313

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 451-460, 2022

Authors: Kuksa, Pavel P. | Liu, Chia-Lun | Fu, Wei | Qu, Liming | Zhao, Yi | Katanic, Zivadin | Clark, Kaylyn | Kuzma, Amanda B. | Ho, Pei-Chuan | Tzeng, Kai-Teh | Valladares, Otto | Chou, Shin-Yi | Naj, Adam C. | Schellenberg, Gerard D. | Wang, Li-San | Leung, Yuk Yee

Article Type: Research Article

Abstract: Background: Recent Alzheimer’s disease (AD) genetics findings from genome-wide association studies (GWAS) span progressively larger and more diverse populations and outcomes. Currently, there is no up-to-date resource providing harmonized and searchable information on all AD genetic associations found by GWAS, nor linking the reported genetic variants and genes with functional and genomic annotations. Objective: Create an integrated/harmonized, and literature-derived collection of population-specific AD genetic associations. Methods: We developed the Alzheimer’s Disease Variant Portal (ADVP), an extensive collection of associations curated from >200 GWAS publications from Alzheimer’s Disease Genetics Consortium and other consortia. Genetic associations were systematically …extracted, harmonized, and annotated from both the genome-wide significant and suggestive loci reported in these publications. To ensure consistent representation of AD genetic findings, all the extracted genetic association information was harmonized across specifically designed publication, variant, and association categories. Results: ADVP V1.0 (February 2021) catalogs 6,990 associations related to disease-risk, expression quantitative traits, endophenotypes, or neuropathology. This extensive harmonization effort led to a catalog containing >900 loci, >1,800 variants, >80 cohorts, and 8 populations. Besides, ADVP provides investigators with a seamless integration of genomic and publicly available functional annotations across multiple databases per harmonized variant and gene records, thus facilitating further understanding and analyses of these genetics findings. Conclusion: ADVP is a valuable resource for investigators to quickly and systematically explore high-confidence AD genetic findings and provides insights into population-specific AD genetic architecture. ADVP is continually maintained and enhanced by NIAGADS and is freely accessible at https://advp.niagads.org . Show more

Keywords: AD GWAS literature curation, Alzheimer’s disease, data curation, database, genome-wide association studies, harmonization

DOI: 10.3233/JAD-215055

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 461-477, 2022

Authors: Levy, Boaz | Priest, Amanda | Delaney, Tyler | Hogan, Jacqueline | Herrawi, Farahdeba

Article Type: Research Article

Abstract: Background: Preventing dementia warrants the pragmatic engagement of primary care. Objective: This study predicted conversion to dementia 12 months before diagnosis with indicators that primary care can utilize within the practical constraints of routine practice. Methods: The study analyzed data from the Alzheimer’s Disease Neuroimaging Initiative (Total sample = 645, converting participants = 54). It predicted the conversion from biological (plasma neurofilament light chain), cognitive (Trails Making Test– B), and functional (Functional Activities Questionnaire) measures, in addition to demographic variables (age and education). Results: A Gradient Booster Trees classifier effectively predicted the conversion, based on a Synthetic Minority …Oversampling Technique (n  = 1,290, F1 Score = 92, AUC = 94, Recall = 87, Precision = 97, Accuracy = 92). Subsequent analysis indicated that the MCI False Positive group (i.e., non-converting participants with cognitive impairment flagged by the model for prospective conversion) scored significantly lower on multiple cognitive tests (Montreal Cognitive Assessment, p  < 0.002; ADAS-13, p  < 0.0004; Rey Auditory Verbal Learning Test, p  < 0.002/0.003) than the MCI True Negative group (i.e., correctly classified non-converting participants with cognitive impairment). These groups also differed in CSF tau levels (p  < 0.04), while consistent effect size differences emerged in the all-pairwise comparisons of hippocampal volume and CSF Aβ1 - 42 . Conclusion: The model effectively predicted 12-month conversion to dementia and further identified non-converting participants with MCI, in the False Positive group, at relatively higher neurocognitive risk. Future studies may seek to extend these results to earlier prodromal phases. Detection of dementia before diagnosis may be feasible and practical in primary care settings, pending replication of these findings in diverse clinical samples. Show more

Keywords: Alzheimer’s disease, dementia, pre-diagnostic detection, prevention, primary care, screening

DOI: 10.3233/JAD-215242

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 479-490, 2022

Authors: Josephs, Kennedy A. | Pham, Nha Trang Thu | Graff-Radford, Jonathan | Machulda, Mary M. | Lowe, Val J. | Whitwell, Jennifer L.

Article Type: Research Article

Abstract: Background: It has been hypothesized that medial temporal sparing may be related to preserved posterior cingulate metabolism and the cingulate island sign (CIS) on [18 F]fluorodeoxyglucose (FDG) PET in posterior cortical atrophy (PCA). Objective: To assess the severity of medial temporal atrophy in PCA and determine whether the presence of a CIS is related to medial temporal sparing. Methods: Fifty-five PCA patients underwent MRI and FDG-PET. The degree and symmetry of medial temporal atrophy on MRI was visually assessed using a five-point scale for both hemispheres. Visual assessments of FDG-PET coded the presence/absence of a CIS …and whether the CIS was symmetric or asymmetric. Hippocampal volumes and a quantitative CIS were also measured. Results: Medial temporal atrophy was most commonly mild or moderate, was symmetric in 55% of patients, and when asymmetric was most commonly worse on the right (76%). Older age and worse memory performance were associated with greater medial temporal atrophy. The CIS was observed in 44% of the PCA patients and was asymmetric in 50% of these. The patients with a CIS showed greater medial temporal asymmetry, but did not show lower medial temporal atrophy scores, compared to those without a CIS. Hippocampal volumes were not associated with quantitative CIS. Conclusion: Mild medial temporal atrophy is a common finding in PCA and is associated with memory impairment. However, medial temporal sparing was not related to the presence of a CIS in PCA. Show more

Keywords: Cingulate island sign, FDG-PET, hippocampus, MRI, visual assessment

DOI: 10.3233/JAD-215263

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 491-498, 2022

Authors: McNerney, M. Windy | Heath, Alesha | Narayanan, Sindhu K. | Yesavage, Jerome

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is a debilitating disorder involving the loss of plasticity and cholinergic neurons in the cortex. Pharmaceutical treatments are limited in their efficacy, but brain stimulation is emerging as a treatment for diseases of cognition. More research is needed to determine the biochemical mechanisms and treatment efficacy of this technique. Objective: We aimed to determine if forebrain repetitive transcranial magnetic stimulation can improve cortical BDNF gene expression and cholinergic signaling in the 3xTgAD mouse model of AD. Methods: Both B6 wild type mice and 3xTgAD mice aged 12 months were given daily treatment …sessions for 14 days or twice weekly for 6 weeks. Following treatment, brain tissue was extracted for immunological stains for plaque load, as well as biochemical analysis for BDNF gene expression and cholinergic signaling via acetylcholinesterase and choline acetyltransferase ELISA assays. Results: For the 3xTgAD mice, both 14 days and 6 weeks treatment regimens resulted in an increase in BDNF gene expression relative to sham treatment, with a larger increase in the 6-week group. Acetylcholinesterase activity also increased for both treatments in 3xTgAD mice. The B6 mice only had an increase in BDNF gene expression for the 6-week group. Conclusion: Brain stimulation is a possible non-invasive and nonpharmaceutical treatment option for AD as it improves both plasticity markers and cholinergic signaling in an AD mouse model. Show more

Keywords: Acetylcholinesterase, brain-derived neurotrophic factor, cortex, mouse, transcranial magnetic stimulation

DOI: 10.3233/JAD-215361

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 499-507, 2022

Authors: George, Daniel R. | Whitehouse, Peter J.

Article Type: Book Review

DOI: 10.3233/JAD-220035

Citation: Journal of Alzheimer's Disease, vol. 86, no. 1, pp. 509-510, 2022