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

Authors: Sultana, Munira | Camicioli, Richard | Dixon, Roger A. | Whitehead, Shawn | Pieruccini-Faria, Frederico | Petrotchenko, Evgeniy | Speechley, Mark | Borchers, Christoph H. | Montero-Odasso, Manuel

Article Type: Research Article

Abstract: Background: Older adults presenting with dual-decline in cognition and walking speed face a 6-fold higher risk for dementia compared with those showing no decline. We hypothesized that the metabolomics profile of dual-decliners would be unique even before they show signs of decline in cognition and gait speed. Objective: The objective of this study was to determine if plasma metabolomics signatures can discriminate dual-decliners from no decliners, purely cognitive decliners, and purely motor decliners prior to decline. Methods: A retrospective cross-sectional study using baseline plasma for untargeted metabolomics analyses to investigate early signals of later dual-decline status …in study participants (n  = 76) with convenient sampling. Dual-decline was operationalized as decline in gait speed (>10 cm/s) and cognition (>2 points decline in Montreal Cognitive Assessment score) on at least two consecutive 6-monthly assessments. The participants’ decliner status was evaluated 3 years after the blood sample was collected. Pair-wise comparison of detected compounds was completed using principal components and hierarchical clustering analyses. Results: Analyses did not detect any cluster separation in untargeted metabolomes across baseline groups. However, follow-up analyses of specific molecules detected 4 compounds (17-Hydroxy-12-(hydroxymethyl)-10-oxo-8 oxapentacyclomethyl hexopyranoside, Fleroxacin, Oleic acid, and 5xi-11,12-Dihydroxyabieta-8(14),9(11),12-trien-20-oic acid) were at significantly higher concentration among the dual-decliners compared to non-decliners. The pure cognitive decliner group had significantly lower concentration of six compounds (1,3-nonanediol acetate, 4-(2-carboxyethyl)-2-methoxyphenyl beta-D-glucopyranosiduronic acid, oleic acid, 2E-3-[4-(sulfo-oxy)phenyl] acrylic acid, palmitelaidic acid, and myristoleic acid) compared to the non-decliner group. Conclusions: The unique metabolomics profile of dual-decliners warrants follow-up metabolomics analysis. Results may point to modifiable pathways. Show more

Keywords: Aging, Alzheimer’s disease, cognition, diagnosis, gait, metabolomics

DOI: 10.3233/JAD-230683

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-9, 2023

Authors: Grant, William B. | Blake, Steven M.

Article Type: Review Article

Abstract: Diet is an important nonpharmacological risk-modifying factor for Alzheimer’s disease (AD). The approaches used here to assess diet’s role in the risk of AD include multi-country ecological studies, prospective and cross-sectional observational studies, and laboratory studies. Ecological studies have identified fat, meat, and obesity from high-energy diets as important risk factors for AD and reported that AD rates peak about 15–20 years after national dietary changes. Observational studies have compared the Western dietary pattern with those of the Dietary Approaches to Stop Hypertension (DASH), Mediterranean (MedDi), and Mediterranean–DASH Intervention for Neurodegenerative Delay (MIND) diets. Those studies identified AD risk factors …including higher consumption of saturated and total fats, meat, and ultraprocessed foods and a lower risk of AD with higher consumption of fruits, legumes, nuts, omega-3 fatty acids, vegetables, and whole grains. Diet-induced factors associated with a significant risk of AD include inflammation, insulin resistance, oxidative stress, elevated homocysteine, dietary advanced glycation end products, and trimethylamine N -oxide. The molecular mechanisms by which dietary bioactive components and specific foods affect risk of AD are discussed. Given most countries’ entrenched food supply systems, the upward trends of AD rates would be hard to reverse. However, for people willing and able, a low–animal product diet with plenty of anti-inflammatory, low–glycemic load foods may be helpful. Show more

Keywords: Advanced glycation end products, Alzheimer’s disease, dementia, diet, meat, neuroinflammation, obesity, saturated fat, TMAO, ultraprocessed foods

DOI: 10.3233/JAD-230418

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-30, 2023

Authors: Lardelli, Michael | Baer, Lachlan | Hin, Nhi | Allen, Angel | Pederson, Stephen Martin | Barthelson, Karissa

Article Type: Research Article

Abstract: The degree to which non-human animals can be used to model Alzheimer’s disease is a contentious issue, particularly as there is still widespread disagreement regarding the pathogenesis of this neurodegenerative dementia. The currently popular transgenic models are based on artificial expression of genes mutated in early onset forms of familial Alzheimer’s disease (EOfAD). Uncertainty regarding the veracity of these models led us to focus on heterozygous, single mutations of endogenous genes (knock-in models) as these most closely resemble the genetic state of humans with EOfAD, and so incorporate the fewest assumptions regarding pathological mechanism. We have generated a number of …lines of zebrafish bearing EOfAD-like and non-EOfAD-like mutations in genes equivalent to human PSEN1 , PSEN2 , and SORL1 . To analyze the young adult brain transcriptomes of these mutants, we exploited the ability of zebrafish to produce very large families of simultaneous siblings composed of a variety of genotypes and raised in a uniform environment. This “intra-family” analysis strategy greatly reduced genetic and environmental “noise” thereby allowing detection of subtle changes in gene sets after bulk RNA sequencing of entire brains. Changes to oxidative phosphorylation were predicted for all EOfAD-like mutations in the three genes studied. Here we describe some of the analytical lessons learned in our program combining zebrafish genome editing with transcriptomics to understand the molecular pathologies of neurodegenerative disease. Show more

Keywords: Alzheimer’s disease, early onset Alzheimer’s disease, gene expression profiling, genetic, models, transcriptome, zebrafish

DOI: 10.3233/JAD-230522

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-15, 2023

Authors: Qaiser, Hammad | Uzair, Mohammad | Al-Regaiey, Khalid | Rafiq, Shafia | Arshad, Muhammad | Yoo, Woo-Kyoung | Arain, Osama Zahid | Kaleem, Imdad | Abualait, Turki | Wang, Lan | Wang, Ran | Bashir, Shahid

Article Type: Review Article

Abstract: Alzheimer’s disease (AD) is the most common form of dementia and a public health problem. It exhibits significant oxidative stress and redox alterations. The antioxidant enzyme systems defend the cellular environment from oxidative stress. One of the redox systems is the thioredoxin system (TS), which exerts decisive control over the cellular redox environment. We aimed to review the protective effects of TS, which include thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. In the following, we discussed the physiological functioning and the role of the TS in maintaining the cellular redox-homeostasis in the AD-damaged brain. Trx protects the cellular environment from …oxidative stress, while TrxR is crucial for the cellular detoxification of reactive oxygen species in the brain. However, TS dysregulation increases the susceptibility to cellular death. The changes in Trx and TrxR levels are significantly associated with AD progression. Though the data from human, animal, and cellular models support the neuroprotective role of TS in the brain of AD patients, the translational potential of these findings to clinical settings is not yet applied. This review summarizes the current knowledge on the emerging role of the TrxR-Trx system in AD. Show more

Keywords: Alzheimer’s disease, antioxidant enzymes, oxidative stress, reactive oxygen species, redox enzymes, thioredoxin, thioredoxin reductase

DOI: 10.3233/JAD-230394

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-12, 2023

Authors: Puentes-Díaz, Nicolás | Chaparro, Diego | Reyes-Marquez, Viviana | Morales-Morales, David | Flores-Gaspar, Areli | Alí-Torres, Jorge

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is the most common form of dementia representing from 60% to 70% of the cases globally. It is a multifactorial disease that, among its many pathological characteristics, has been found to provoke the metal ion dysregulation in the brain, along with an increase in the oxidative stress. There is proof that metallic complexes formed by the amyloid-β peptide (Aβ) and extraneuronal copper can catalyze the production of reactive oxygen species, leading to an increase in oxidative stress, promoting neuronal death. Due to this interaction, bioavailable copper has become an important redox active target to consider within …the search protocols of multifunctional agents for AD’s treatment. Objective: In this study, we examined by using bioinformatics and electronic structure calculations the potential application of 44 salen-type copper chelating ligands and 12 further proposed molecules as possible multifunctional agents in the context of AD. Methods: The candidates were evaluated by combining bioinformatic tools and electronic structure calculations, which allowed us to classify the molecules as potential antioxidants, redistributor-like compounds, and the newly proposed suppressor mechanism. Results: This evaluation demonstrate that salen-type ligands exhibit properties suitable for interfering in the chain of copper-induced oxidative stress reactions present in AD and potential redistributor and suppressor activity for copper ions. Finally, a novel set of plausible candidates is proposed and evaluated. Conclusion: According to the evaluated criteria, a subset of 13 salen-type candidates was found to exhibit promissory pharmacological properties in the AD framework and were classified according to three plausible action mechanisms. Show more

Keywords: Alzheimer’s disease, copper binding affinities, density functional theory calculations, salen-type ligands, standard reduction potentials

DOI: 10.3233/JAD-230542

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-14, 2023

Authors: Chum, Phoebe P. | Bishara, Mary A. | Solis, Summer R. | Behringer, Erik J.

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is associated with impaired cerebral circulation which underscores diminished delivery of blood oxygen and nutrients to and throughout the brain. In the 3xTg-AD mouse model, we have recently found that > 10 cerebrovascular miRNAs pertaining to vascular permeability, angiogenesis, and inflammation (e.g., let-7d, miR-99a, miR-132, miR-133a, miR-151-5p, and miR-181a) track early development of AD. Further, endothelial-specific miRNAs (miR-126-3p, miR-23a/b, miR-27a) alter with onset of overall AD pathology relative to stability of smooth muscle/pericyte-specific miRNAs (miR-143, miR-145). Objective: We tested the hypothesis that cerebrovascular miRNAs indicating AD pathology share mRNA targets that regulate key endothelial cell functions …such as angiogenesis, vascular permeability, and blood flow regulation. Methods: As detected by NanoString nCounter miRNA Expression panel for 3xTg-AD mice, 61 cerebrovascular miRNAs and respective mRNA targets were examined using Ingenuity Pathway Analysis for canonical Cardiovascular (Cardio) and Nervous System (Neuro) Signaling. Results: The number of targets regulated per miRNA were 21±2 and 33±3 for the Cardio and Neuro pathways respectively, whereby 14±2 targets overlap among pathways. Endothelial miRNAs primarily target members of the PDE, PDGF, SMAD, and VEGF families. Individual candidates regulated by≥4 miRNAs that best mark AD pathology presence in 3xTg-AD mice include CFL2, GRIN2B, PDGFB, SLC6A1, SMAD3, SYT3, and TNFRSF11B. Conclusion: miRNAs selective for regulation of endothelial function and respective downstream mRNA targets support a molecular basis for dysregulated cerebral blood flow regulation coupled with enhanced cell growth, proliferation, and inflammation. Show more

Keywords: Alzheimer’s disease, brain endothelium, mRNA targets, vascular dysfunction

DOI: 10.3233/JAD-230300

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-48, 2023

Authors: Mamelak, Mortimer

Article Type: Review Article

Abstract: The deterioration of the brain’s microvasculature, particularly in the hippocampus, appears to be a very early event in the development of Alzheimer’s disease (AD), preceding even the deposition of amyloid-β. A damaged microvasculature reduces the supply of oxygen and glucose to this region and limits the production of energy, ATP. The damage may be a function of the rise with age in the expression and activity of NADPH oxidase (NOX) in these microvessels. This rise renders these vessels vulnerable to the effects of oxidative stress and inflammation. The rise in NOX activity with age is even more marked in the …AD brain where an inverse correlation has been demonstrated between NOX activity and cognitive ability. Apocynin, a putative NOX inhibitor, has been shown to block the damaging effects of NOX activation. Apocynin acts as a strong scavenger of H2 O2, and as a weak scavenger of superoxide. Like apocynin, sodium oxybate (SO) has also been shown to block the toxic effects of NOX activation. The application of SO generates NADPH and ATP. SO inhibits oxidative stress and maintains normal cerebral ATP levels under hypoxic conditions. Moreover, it acts epigenetically to attenuate the expression of NOX. SO may delay the onset and slow the progress of AD by suppling energy and maintaining an antioxidative environment in the brain throughout the night. The slow wave activity produced by SO may also activate the glymphatic system and promote the clearance of amyloid-β from the brain. Show more

Keywords: Alzheimer’s disease, amyloid-β , apocynin, cerebral microvasculature, NADPH, NADPH oxidase, oxidative stress, sodium oxybate

DOI: 10.3233/JAD-230415

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-10, 2023

Authors: Ly, Maria | Yu, Gary Z. | Chwa, Won Jong | Raji, Cyrus A.

Article Type: Systematic Review

Abstract: Background: Given the advent of large-scale neuroimaging data-driven endeavors for Alzheimer’s disease, there is a burgeoning need for well-characterized neuroimaging databases of healthy individuals. With the rise of initiatives around the globe for the rapid and unrestricted sharing of data resources, there is now an abundance of open-source neuroimaging datasets available to the research community. However, there is not yet a systematic review that fully details the demographic information and modalities actually available in all open access neuroimaging databases around the globe. Objective: This systematic review aims to provide compile a list of MR structural imaging databases encompassing …healthy individuals across the lifespan. Methods: In this systematic review, we searched EMBASE and PubMed until May 2022 for open-access neuroimaging databases containing healthy control participants of any age, race, with normal development and cognition having at least one structural T1-weighted neuroimaging scan. Results: A total of 403 databases were included, for up to total of 48,268 participants with all available demographic information and imaging modalities detailed in Supplementary Table 1 . There were significant trends noted when compiling normative databases for this systematic review, notably that 11.7% of databases included reported ethnicity in their participants, with underrepresentation of many socioeconomic groups globally. Conclusions: As efforts to improve primary prevention of AD may require a broader perspective including increased relevance of earlier stages in life, and strategies in addressing modifiable risk factors may be individualized to specific demographics, improving data characterization to be richer and more rigorous will greatly enhance these efforts. Show more

Keywords: Aging, Alzheimer’s disease, database, neuroimaging, normative, open-access, representation, social determinants of health

DOI: 10.3233/JAD-230738

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-11, 2023

Authors: Snytnikova, Olga | Telegina, Darya | Savina, Ekaterina | Tsentalovich, Yuri | Kolosova, Nataliya

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is the most common type of dementia in the elderly. Incomplete knowledge about the pathogenesis of this disease determines the absence of medications for the treatment of AD today. Animal models can provide the necessary knowledge to understand the mechanisms of biochemical processes occurring in the body in health and disease. Objective: To identify the most promising metabolomic predictors and biomarkers reflecting metabolic disorders in the development of AD signs. Methods: High resolution 1 H NMR spectroscopy was used for quantitative metabolomic profiling of the hippocampus of OXYS rats, an animal model …of sporadic AD, which demonstrates key characteristics of this disease. Animals were examined during several key periods: 20 days group corresponds to the “preclinical” period preceding the development of AD signs, during their manifestation (3 months), and active progression (18 months). Wistar rats of the same age were used as control. Results: Ranges of variation and mean concentrations were established for 59 brain metabolites. The main metabolic patterns during aging, which are involved in energy metabolism pathways and metabolic shifts of neurotransmitters, have been established. Of particular note is the significant increase of scyllo-inositol and decrease of hypotaurine in the hippocampus of OXYS rats as compared to Wistars for all studied age groups. Conclusions: We suggest that the accumulation of scyllo-inositol and the reduction of hypotaurine in the brain, even at an early age, can be considered as predictors and potential biomarkers of the development of AD signs in OXYS rats and, probably, in humans. Show more

Keywords: Aging, Alzheimer’s disease, hippocampal metabolome, hypotaurine, nuclear magnetic resonance spectroscopy, OXYS rats, scyllo-inositol

DOI: 10.3233/JAD-230706

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-18, 2023

Authors: Briceño, Emily M. | Dhakal, Usha | Sharma, Uttam | Adhikari, Nabin | Pradhan, Meeta S. | Shrestha, Lochana | Jalan, Pankaj | Rai, Janak | Langa, Kenneth M. | Lee, Jinkook | Ghimire, Dirgha | de Leon, Carlos F. Mendes

Article Type: Review Article

Abstract: The population of Nepal is rapidly aging, as in other low and middle-income countries, and the number of individuals living with Alzheimer’s Disease and related dementias (ADRD) is expected to increase. However, information about the neuropsychological assessment of ADRD in Nepal is lacking. We first aimed to examine the needs, challenges, and opportunities associated with the neuropsychological assessment of older adults in Nepal for population-based ADRD ascertainment. Second, we introduce the Chitwan Valley Family Study-Study of Cognition and Aging in Nepal (CVFS-SCAN), which is poised to address these needs, and its collaboration with the Harmonized Cognitive Assessment Protocol (HCAP) international …network. We reviewed the existing literature on the prevalence, risk factors, available neuropsychological assessment instruments, and sociocultural factors that may influence the neuropsychological assessment of older adults for ADRD ascertainment in Nepal. Our review revealed no existing population-based data on the prevalence of ADRD in Nepal. Very few studies have utilized formal cognitive assessment instruments for ADRD assessment, and there have been no comprehensive neuropsychological assessment instruments that have been validated for the assessment of ADRD in Nepal. We describe how the CVFS-SCAN study will address this need through careful adaptation of the HCAP instrument. We conclude that the development of culturally appropriate neuropsychological assessment instruments is urgently needed for the population-based assessment of ADRD in Nepal. The CVFS-SCAN is designed to address this need and will contribute to the growth of global and equitable neuropsychology and to the science of ADRD in low- and middle-income countries. Show more

Keywords: Alzheimer’s disease and related dementias, cognitive aging, cultural neuropsychology, global health, mild cognitive impairment

DOI: 10.3233/JAD-230906

Citation: Journal of Alzheimer's Disease, vol. Pre-press, no. Pre-press, pp. 1-14, 2023