Journal of Alzheimer's Disease - Volume Pre-press, issue Pre-press

Authors: Secnik, Juraj | Xu, Hong | Schwertner, Emilia | Hammar, Niklas | Alvarsson, Michael | Winblad, Bengt | Eriksdotter, Maria | Garcia-Ptacek, Sara | Religa, Dorota

Article Type: Research Article

Abstract: Background: The effectiveness of glucose-lowering drugs (GLDs) is unknown among patients with dementia. Objective: To analyze all-cause mortality among users of six GLDs in dementia and dementia-free subjects, respectively. Methods: This was a longitudinal open-cohort registry-based study using data from the Swedish Dementia Registry, Total Population Register, and four supplemental registers providing data on dementia status, drug usage, confounders, and mortality. The cohort comprised 132,402 subjects with diabetes at baseline, of which 11,401 (8.6%) had dementia and 121,001 (91.4%) were dementia-free. Subsequently, comparable dementia – dementia-free pairs were sampled. Then, as-treated and intention-to-treat exposures to metformin, …insulin, sulfonylurea, dipeptidyl-peptidase-4 inhibitors, glucagon-like peptide-1 analogues (GLP-1a), and sodium-glucose cotransporter-2 inhibitors (SGLT-2i) were analyzed in the parallel dementia and dementia-free cohorts. Confounding was addressed using inverse-probability weighting and propensity-score matching, and flexible parametric survival models were used to produce hazard ratios (HR) and 95% confidence intervals (CI) of the association between GLDs and all-cause mortality. Results: In the as-treated models, increased mortality was observed among insulin users with dementia (HR 1.34 [95%CI 1.24–1.45]) as well as in dementia-free subjects (1.54 [1.10–1.55]). Conversely, sulfonylurea was associated with higher mortality only in dementia subjects (1.19 [1.01–1.42]). GLP-1a (0.44 [0.25–0.78]) and SGLT-2i users with dementia (0.43 [0.23–0.80]) experienced lower mortality compared to non-users. Conclusion: Insulin and sulfonylurea carried higher mortality risk among dementia patients, while GLP-1a and SGLT-2i were associated with lower risk. GLD-associated mortality varied between dementia and comparable dementia-free subjects. Further studies are needed to optimize GLD use in dementia patients. Show more

Keywords: Antidiabetics, dementia, diabetes, hyperglycemia, mortality, propensity-score

DOI: 10.3233/JAD-215337

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-13, 2021

Authors: Liu, Mingjing | Guo, Shipeng | Huang, Daochao | Hu, Dongjie | Wu, Yili | Zhou, Weihui | Song, Weihong

Article Type: Research Article

Abstract: Background: Chronic alcohol consumption can alter the structure of the central nervous system and disrupt cognitive function. Alcoholics are more likely to develop neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). However, the role of alcohol in promoting neurotoxicity and neurodegeneration remains unclear. Objective: In this study, we aimed at estimating the effects of chronic binge alcohol exposure on brain transcriptome and behavior changes in a chronic “Drinking in the Dark” (DID) mouse model. Methods: The adult C57BL/6J male mice were exposed to alcohol for 4 weeks. RNA-seq was applied to assess the …effects of chronic alcohol exposure on transcriptome in brain. The open field test and novel object recognition test were used to assess the changes of anxiety level, locomotive function, and short-term memory induced by alcohol. RNA-seq analysis revealed that chronic alcohol exposure caused significant change in the brain transcriptome, especially in prefrontal cortex. Results: The gene dysregulation caused by chronic alcohol exposure includes pathways related to mitochondrial energy metabolism (such as oxidative phosphorylation) and multiple neurodegenerative diseases (such as AD and PD). Furthermore, the pathway and network analyses suggest that the genes involved in mitochondrial energy metabolism, ubiquitin-proteasome system, Wnt signaling pathway, and microtubules may attribute to the neurotoxicity and neurodegeneration caused by chronic alcohol consumption. Additionally, locomotive function was also significantly impaired. Conclusion: This work provides gene transcriptional profile data for future research on alcohol-induced neurodegenerative diseases, especially AD and PD. Show more

Keywords: Brain, chronic alcohol consumption, gene expression, neurodegeneration

DOI: 10.3233/JAD-215508

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-17, 2021

Authors: Stepler, Kaitlyn E. | Gillyard, Taneisha R. | Reed, Calla B. | Avery, Tyra M. | Davis, Jamaine S. | Robinson, Renã A.S.

Article Type: Review Article

Abstract: African American/Black adults are twice as likely to have Alzheimer’s disease (AD) compared to non-Hispanic White adults. Genetics partially contributes to this disparity in AD risk, among other factors, as there are several genetic variants associated with AD that are more prevalent in individuals of African or European ancestry. The phospholipid-transporting ATPase ABCA7 (ABCA7 ) gene has stronger associations with AD risk in individuals with African ancestry than in individuals with European ancestry. In fact, ABCA7 has been shown to have a stronger effect size than the apolipoprotein E (APOE ) ɛ 4 allele in African American/Black adults. ABCA7 …is a transmembrane protein involved in lipid homeostasis and phagocytosis. ABCA7 dysfunction is associated with increased amyloid-beta production, reduced amyloid-beta clearance, impaired microglial response to inflammation, and endoplasmic reticulum stress. This review explores the impact of ABCA7 mutations that increase AD risk in African American/Black adults on ABCA7 structure and function and their contributions to AD pathogenesis. The combination of biochemical/biophysical and ‘omics-based studies of these variants needed to elucidate their downstream impact and molecular contributions to AD pathogenesis is highlighted. Show more

Keywords: African Americans, Alzheimer’s disease, Blacks, health status disparities, human ABCA7 protein, proteomics, single nucleotide polymorphism, subfamily A of ATP binding cassette transporter

DOI: 10.3233/JAD-215306

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-15, 2021

Authors: Miron, Justin | Picard, Cynthia | Labonté, Anne | Auld, Daniel | Poirier, Judes | for the PREVENT-AD research group

Article Type: Research Article

Abstract: Background: In mouse models of amyloidosis, macrophage receptor 1 (MSR1) and neprilysin (NEP) have been shown to interact to reduce amyloid burden in the brain. Objective: The purpose of this study is to analyze these two gene products in combination with apolipoproteins and Aβ 1 - 42 in the cerebrospinal fluid (CSF) and plasma of individuals at different stages of Alzheimer’s disease (AD), as well as in autopsied brain samples from ROSMAP (Religious Orders Study and Memory and Aging Project). Methods: CSF/plasma levels of MSR1 and NEP were measured using the sensitive primer extension assay technology. …CSF Aβ 1 - 42 was assessed with ELISA, while CSF ApoE and ApoJ were measured with the Luminex’s multiplex technology. Brain MSR1 , APOE , and CLU (ApoJ) mRNA levels were measured with RNA-Seq and contrasted to amyloid plaques pathology using CERAD staging. Results: While plasma and CSF MSR1 levels are significantly correlated, this correlation was not observed for NEP. In addition to be highly correlated to one another, CSF levels of both MSR1 and NEP are strongly correlated with AD status and CSF Aβ 1 - 42 , ApoE, and ApoJ levels. In the cortical tissues of subjects from ROSMAP, MSR1 mRNA levels are correlated with CLU mRNA levels and the CERAD scores but not with APOE mRNA levels. Conclusion: The discrepancies observed between CSF/plasma levels of MSR1 and NEP with CSF Aβ 1 - 42 and ApoE concentrations can be explained by many factors, such as the disease stage or the involvement of the blood-brain barrier breakdown that leads to the infiltration of peripheral monocytes or macrophages. Show more

Keywords: Alzheimer’s disease, amyloid, biomarkers, inflammation, MSR1, NEP

DOI: 10.3233/JAD-215410

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-13, 2021

Authors: Bakker, Els D. | van Maurik, Ingrid S. | Mank, Arenda | Zwan, Marissa D. | Waterink, Lisa | van den Buuse, Susanne | van den Broeke, Jennifer R. | Gillissen, Freek | van de Beek, Marleen | Lemstra, Evelien | van den Bosch, Karlijn A. | van Leeuwenstijn, Mardou | Bouwman, Femke H. | Scheltens, Philip | van der Flier, Wiesje M.

Article Type: Research Article

Abstract: Background: The COVID-19 pandemic poses enormous social challenges, especially during lockdown. People with cognitive decline and their caregivers are particularly at risk of lockdown consequences. Objective: To investigate psychosocial effects in (pre-)dementia patients and caregivers during second lockdown and compare effects between first and second lockdown. Methods: We included n  = 511 (pre-)dementia patients and n  = 826 caregivers from the Amsterdam Dementia Cohort and via Alzheimer Nederland. All respondents completed a self-designed survey on psychosocial effects of COVID-19. We examined relations between experienced support and psychosocial and behavioral symptoms using logistic regression. In a subset of patients …and caregivers we compared responses between first and second lockdown using generalized estimating equation. Results: The majority of patients (≥58%) and caregivers (≥60%) reported that family and friends, hobbies, and music helped them cope. Support from family and friends was strongly related to less negative feelings in patients (loneliness: OR = 0.3[0.1–0.6]) and caregivers (loneliness: OR = 0.2[0.1–0.3]; depression: OR = 0.4[0.2–0.5]; anxiety: OR = 0.4[0.3–0.6]; uncertainty: OR = 0.3[0.2–0.5]; fatigue: OR = 0.3[0.2–0.4]; stress: OR = 0.3[0.2–0.5]). In second lockdown, less psychosocial and behavioral symptoms were reported compared to first lockdown (patients; e.g., anxiety: 22% versus 13%, p  = 0.007; apathy: 27% versus 8%, p  < 0.001, caregivers; e.g., anxiety: 23% versus 16%, p  = 0.033; patient’s behavioral problems: 50% versus 35%, p  < 0.001). Patients experienced more support (e.g., family and friends: 52% versus 93%, p  < 0.001; neighbors: 28% versus 66%, p  < 0.001). Conclusion: During second lockdown, patients and caregivers adapted to challenges posed by lockdown, as psychosocial and behavioral effects decreased, while patients experienced more social support compared to first lockdown. Support from family and friends is a major protective factor for negative outcomes in patients and caregivers. Show more

Keywords: Behavioral effects, caregiver, COVID-19, dementia, experienced support, lockdown, mild cognitive impairment, psychosocial effects, subjective cognitive decline

DOI: 10.3233/JAD-215342

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-9, 2021

Authors: Schaffert, Jeff | LoBue, Christian | Hynan, Linda S. | Hart Jr., John | Rossetti, Heidi | Carlew, Anne R. | Lacritz, Laura | White III, Charles L. | Cullum, C. Munro

Article Type: Research Article

Abstract: Background: Life expectancy (LE) following Alzheimer’s disease (AD) is highly variable. The literature to date is limited by smaller sample sizes and clinical diagnoses. Objective: No study to date has evaluated predictors of AD LE in a retrospective large autopsy-confirmed sample, which was the primary objective of this study. Methods: Participants (≥50 years old) clinically and neuropathologically diagnosed with AD were evaluated using National Alzheimer’s Coordinating Center (N = 1,401) data. Analyses focused on 21 demographic, medical, neuropsychiatric, neurological, functional, and global cognitive predictors of LE at AD dementia diagnosis. These 21 predictors were evaluated in univariate analyses. …Variables found to be significant were then entered into a forward multiple regression. LE was defined as months between AD diagnosis and death. Results: Fourteen predictors were significant in univariate analyses and entered into the regression. Seven predictors explained 27% of LE variance in 764 total participants. Mini-Mental State Examination (MMSE) score was the strongest predictor of LE, followed by sex, age, race/ethnicity, neuropsychiatric symptoms, abnormal neurological exam results, and functional impairment ratings. Post-hoc analyses revealed correlations of LE were strongest with MMSE ≤12. Conclusion: Global cognitive functioning was the strongest predictor of LE following diagnosis, and AD patients with severe impairment had the shortest LE. AD patients who are older, male, white, and have more motor symptoms, functional impairment, and neuropsychiatric symptoms were also more likely have shorter LE. While this model cannot provide individual prognoses, additional studies may focus on these variables to enhance predictions of LE in patients with AD. Show more

Keywords: Alzheimer’s disease, autopsy-confirmed, dementia, life expectancy, mortality

DOI: 10.3233/JAD-215200

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-11, 2021

Authors: Eastman, Guillermo | Sharlow, Elizabeth R. | Lazo, John S. | Bloom, George S. | Sotelo-Silveira, José R.

Article Type: Research Article

Abstract: Background: Defining cellular mechanisms that drive Alzheimer’s disease (AD) pathogenesis and progression will be aided by studies defining how gene expression patterns change during pre-symptomatic AD and ensuing periods of declining cognition. Previous studies have emphasized changes in transcriptome, but not translatome regulation, leaving the ultimate results of gene expression alterations relatively unexplored in the context of AD. Objective: To identify genes whose expression might be regulated at the transcriptome and translatome levels in AD, we analyzed gene expression in cerebral cortex of two AD model mouse strains, CVN (APPSwDI ;NOS2 -/- ) and Tg2576 (APPSw ), …and their companion wild type (WT) strains at 6 months of age by tandem RNA-Seq and Ribo-Seq (ribosome profiling). Methods: Identical starting pools of bulk RNA were used for RNA-Seq and Ribo-Seq. Differential gene expression analysis was performed at the transcriptome, translatome, and translational efficiency levels. Regulated genes were functionally evaluated by gene ontology tools. Results: Compared to WT mice, AD model mice had similar levels of transcriptome regulation, but differences in translatome regulation. A microglial signature associated with early stages of Aβ accumulation was upregulated at both levels in CVN mice. Although the two mice strains did not share many regulated genes, they showed common regulated pathways related to AβPP metabolism associated with neurotoxicity and neuroprotection. Conclusion: This work represents the first genome-wide study of brain translatome regulation in animal models of AD and provides evidence of a tight and early translatome regulation of gene expression controlling the balance between neuroprotective and neurodegenerative processes in brain. Show more

Keywords: Alzheimer’s disease, amyloid, microglia, RNA-Seq, mRNA translation, transcriptome regulation

DOI: 10.3233/JAD-215357

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-22, 2021

Authors: Lerch, Ondrej | Pařízková, Martina | Vyhnálek, Martin | Nedelská, Zuzana | Hort, Jakub | Laczó, Jan

Article Type: Research Article

Abstract: Background: Cholinergic deficit and medial temporal lobe (MTL) atrophy are hallmarks of Alzheimer’s disease (AD) leading to early allocentric spatial navigation (aSN) impairment. APOE ɛ 4 allele (E4) is a major genetic risk factor for late-onset AD and contributes to cholinergic dysfunction. Basal forebrain (BF) nuclei, the major source of acetylcholine, project into multiple brain regions and, along with MTL and prefrontal cortex (PFC), are involved in aSN processing. Objective: We aimed to determine different contributions of individual BF nuclei atrophy to aSN in E4 positive and E4 negative older adults without dementia and assess whether they …operate on aSN through MTL and PFC or independently from these structures. Methods: 120 participants (60 E4 positive, 60 E4 negative) from the Czech Brain Aging Study underwent structural MRI and aSN testing in real-space arena setting. Hippocampal and BF nuclei volumes and entorhinal cortex and PFC thickness were obtained. Associations between brain regions involved in aSN were assessed using MANOVA and complex model of mutual relationships was built using structural equation modelling (SEM). Results: Path analysis based on SEM modeling revealed that BF Ch1-2, Ch4p, and Ch4ai nuclei volumes were indirectly associated with aSN performance through MTL (pch1 - 2  = 0.039; pch4p  = 0.042) and PFC (pch4ai  = 0.044). In the E4 negative group, aSN was indirectly associated with Ch1-2 nuclei volumes (p  = 0.015), while in the E4 positive group, there was indirect effect of Ch4p nucleus (p  = 0.035). Conclusion: Our findings suggest that in older adults without dementia, BF nuclei affect aSN processing indirectly, through MTL and PFC, and that APOE E4 moderates these associations. Show more

Keywords: Allocentric spatial navigation, apolipoprotein E, basal forebrain, entorhinal cortex, hippocampus, magnetic resonance imaging, prefrontal cortex

DOI: 10.3233/JAD-215034

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-17, 2021

Authors: Dennison, Jessica L. | Volmar, Claude-Henry | Ke, Danbing | Wang, James | Gravel, Emilie | Hammond-Vignini, Sabrina | Li, Zuomei | Timmons, James A. | Lohse, Ines | Hayward, Marshall A. | Brothers, Shaun P. | Wahlestedt, Claes

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) has minimally effective treatments currently. High concentrations of resveratrol, a polyphenol antioxidant found in plants, have been reported to affect several AD-related and neuroprotective genes. To address the low bioavailability of resveratrol, we investigated a novel oral formulation of resveratrol, JOTROLTM, that has shown increased pharmacokinetic properties compared to non-formulated resveratrol in animals and in humans. Objective: We hypothesized that equivalent doses of JOTROL, compared to non-formulated resveratrol, would result in greater brain exposure to resveratrol, and more efficacious responses on AD biomarkers. Methods: For sub-chronic reversal studies, 15-month-old male triple transgenic …(APPSW /PS1M146V /TauP301L ; 3xTg-AD) AD mice were treated orally with vehicle or 50 mg/kg JOTROL for 36 days. For prophylactic studies, male and female 3xTg-AD mice were similarly administered vehicle, 50 mg/kg JOTROL, or 50 mg/kg resveratrol for 9 months starting at 4 months of age. A behavioral battery was run, and mRNA and protein from brain and blood were analyzed for changes in AD-related gene and protein expression. Results: JOTROL displays significantly increased bioavailability over non-formulated resveratrol. Treatment with JOTROL resulted in AD-related gene expression changes (Adam10, Bace1, Bdnf, Psen1 ) some of which were brain region-dependent and sex-specific, as well as changes in inflammatory gene and cytokine levels. Conclusion: JOTROL may be effective as a prophylaxis and/or treatment for AD through increased expression and/or activation of neuroprotective genes, suppression of pro-inflammatory genes, and regulation of central and peripheral cytokine levels. Show more

Keywords: Alzheimer’s disease, inflammation, neuroprotection, resveratrol, sex differences

DOI: 10.3233/JAD-215370

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-18, 2021

Authors: Pritchard, Anna Barlach | Fabian, Zsolt | Lawrence, Clare L. | Morton, Glyn | Crean, StJohn | Alder, Jane E.

Article Type: Research Article

Abstract: Background: The effects of the key pathogens and virulence factors associated with gum disease such as Porphyromonas gingivalis (P. gingivalis ) on the central nervous system is of great interest with respect to development of neuropathologies and hence therapeutics and preventative strategies. Chronic infections and associated inflammation are known to weaken the first line of defense for the brain, the blood-brain barrier (BBB). Objective: The focus of this study is to utilize an established human in vitro BBB model to evaluate the effects of P. gingivalis virulence factors lipopolysaccharide (LPS) and outer membrane vesicles (OMVs) on a …primary-derived human model representing the neurovascular unit of the BBB. Methods: Changes to the integrity of the BBB after application of P. gingivalis LPS and OMVs were investigated and correlated with transport of LPS. Additionally, the effect of P. gingivalis LPS and OMVs on human brain microvascular endothelial cells in monolayer was evaluated using immunofluorescence microscopy. Results: The integrity of the BBB model was weakened by application of P. gingivalis LPS and OMVs, as measured by a decrease in electrical resistance and a recovery deficit was seen in comparison to the controls. Application of P. gingivalis OMVs to a monoculture of human brain microvascular endothelial cells showed disruption of the tight junction zona occludens protein (ZO-1) compared to controls. Conclusion: These findings show that the integrity of tight junctions of the human BBB could be weakened by association with P. gingivalis virulence factors LPS and OMVs containing proteolytic enzymes (gingipains). Show more

Keywords: Alzheimer’s disease, blood-brain barrier, human brain microvascular endothelial cells, in vitro BBB model, microbiome, periodontal disease

DOI: 10.3233/JAD-215054

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-22, 2021