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Movement Disorders : Official Journal... Jun 2024
PubMed: 38943243
DOI: 10.1002/mds.29914 -
Acta Neuropathologica Communications Jun 2024The relationship between amyloidosis and vasculature in cognitive impairment and Alzheimer's disease (AD) pathogenesis is increasingly acknowledged. We conducted a...
The relationship between amyloidosis and vasculature in cognitive impairment and Alzheimer's disease (AD) pathogenesis is increasingly acknowledged. We conducted a quantitative and topographic assessment of retinal perivascular amyloid plaque (AP) distribution in individuals with both normal and impaired cognition. Using a retrospective dataset of scanning laser ophthalmoscopy fluorescence images from twenty-eight subjects with varying cognitive states, we developed a novel image processing method to examine retinal peri-arteriolar and peri-venular curcumin-positive AP burden. We further correlated retinal perivascular amyloidosis with neuroimaging measures and neurocognitive scores. Our study unveiled that peri-arteriolar AP counts surpassed peri-venular counts throughout the entire cohort (P < 0.0001), irrespective of the primary, secondary, or tertiary vascular branch location, with a notable increase among cognitively impaired individuals. Moreover, secondary branch peri-venular AP count was elevated in the cognitively impaired (P < 0.01). Significantly, peri-venular AP count, particularly in secondary and tertiary venules, exhibited a strong correlation with clinical dementia rating, Montreal cognitive assessment score, hippocampal volume, and white matter hyperintensity count. In conclusion, our exploratory analysis detected greater peri-arteriolar versus peri-venular amyloidosis and a marked elevation of amyloid deposition in secondary branch peri-venular regions among cognitively impaired subjects. These findings underscore the potential feasibility of retinal perivascular amyloid imaging in predicting cognitive decline and AD progression. Larger longitudinal studies encompassing diverse populations and AD-biomarker confirmation are warranted to delineate the temporal-spatial dynamics of retinal perivascular amyloid deposition in cognitive impairment and the AD continuum.
Topics: Humans; Male; Female; Aged; Cognitive Dysfunction; Hippocampus; Atrophy; Amyloidosis; Aged, 80 and over; Retrospective Studies; Middle Aged; Plaque, Amyloid; Retinal Diseases; Retinal Vessels; Ophthalmoscopy
PubMed: 38943220
DOI: 10.1186/s40478-024-01810-2 -
Alzheimer's Research & Therapy Jun 2024Amyloid-β (Aβ) and tau are brain hallmarks of Alzheimer's disease (AD), also present in blood as soluble biomarkers or encapsulated in extracellular vesicles (EVs).... (Comparative Study)
Comparative Study
BACKGROUND
Amyloid-β (Aβ) and tau are brain hallmarks of Alzheimer's disease (AD), also present in blood as soluble biomarkers or encapsulated in extracellular vesicles (EVs). Our goal was to assess how soluble plasma biomarkers of AD pathology correlate with the number and content of EVs.
METHODS
Single-molecule enzyme-linked assays were used to quantify Aβ42/40 and tau in plasma samples and neurally-derived EVs (NDEVs) from a cohort of APOE ε4- (n = 168) and APOE ε4+ (n = 68) cognitively normal individuals and AD patients (n = 55). The ratio of CD56 (Neuronal cell-adhesion molecule) to CD81 signal measured by ELISA-DELFIA was used for the relative quantification of NDEVs in plasma samples.
RESULTS
The soluble plasma Aβ42/40 ratio is decreased in AD patients compared to cognitively normal individuals. The amount and content (Aβ40, Aβ42, tau) of plasma NDEVs were similar between groups. Plasma NDEVs quantity remain consistent with aging and between AD and CN individuals. However, the quantity of soluble biomarkers was negatively correlated to NDEVs number in cognitively normal individuals, while in AD patients, this correlation is lost, suggesting a shift in the mechanism underpinning the production and the release of these biomarkers in pathological conditions.
CONCLUSION
Soluble plasma Aβ42/40 ratio is the most robust biomarker to discriminate between AD patients and CN individuals, as it normalizes for the number of NDEVs. Analysis of NDEVs and their content pointed toward peculiar mechanisms of Aβ release in AD. Further research on independent cohorts can confirm our findings and assess whether plasma Aβ and tau need correction by NDEVs for better AD risk identification in CN populations.
Topics: Humans; Alzheimer Disease; Extracellular Vesicles; Biomarkers; Female; Male; Amyloid beta-Peptides; Aged; tau Proteins; Peptide Fragments; Aged, 80 and over; Middle Aged; Cohort Studies; Apolipoprotein E4
PubMed: 38943196
DOI: 10.1186/s13195-024-01508-6 -
Acta Neuropathologica Communications Jun 2024
PubMed: 38943188
DOI: 10.1186/s40478-024-01819-7 -
Acta Neuropathologica Communications Jun 2024We quantified and determined for the first time the distribution pattern of the neuropeptide NPFF in the human cerebral cortex and subjacent white matter. To do so, we...
We quantified and determined for the first time the distribution pattern of the neuropeptide NPFF in the human cerebral cortex and subjacent white matter. To do so, we studied n = 9 cases without neurological disorders and n = 22 cases with neurodegenerative diseases, including sporadic amyotrophic lateral sclerosis (ALS, n = 8), Alzheimer's disease (AD, n = 8), Pick's disease (PiD, n = 3), and schizophrenia (n = 3). NPFF-immunopositive cells were located chiefly, but not exclusively, in the superficial white matter and constituted there a subpopulation of white matter interstitial cells (WMIC): Pyramidal-like and multipolar somata predominated in the gyral crowns, whereas bipolar and ovoid somata predominated in the cortex surrounding the sulci. Their sparsely ramified axons were unmyelinated and exhibited NPFF-positive bead-like varicosities. We found significantly fewer NPFF-immunopositive cells in the gray matter of the frontal, cingulate, and superior temporal gyri of both sporadic ALS and late-stage AD patients than in controls, and significantly fewer NPFF-positive cells in the subjacent as well as deep white matter of the frontal gyrus of these patients compared to controls. Notably, the number of NPFF-positive cells was also significantly lower in the hippocampal formation in AD compared to controls. In PiD, NPFF-positive cells were present in significantly lower numbers in the gray and white matter of the cingulate and frontal gyrii in comparison to controls. In schizophrenic patients, lower wNPFF cell counts in the neocortex were significant and global (cingulate, frontal, superior temporal gyrus, medial, and inferior gyri). The precise functions of NPFF-positive cells and their relationship to the superficial corticocortical white matter U-fibers are currently unknown. Here, NPFF immunohistochemistry and expression characterize a previously unrecognized population of cells in the human brain, thereby providing a new entry-point for investigating their physiological and pathophysiological roles.
Topics: Humans; White Matter; Male; Schizophrenia; Female; Cerebral Cortex; Aged; Middle Aged; Neurodegenerative Diseases; Aged, 80 and over; Oligopeptides; Adult; Neurons
PubMed: 38943180
DOI: 10.1186/s40478-024-01792-1 -
BMC Geriatrics Jun 2024Critical wandering occurs when an individual living with dementia leaves a location and is unaware of place or time. Critical wandering incidents are expected to...
BACKGROUND
Critical wandering occurs when an individual living with dementia leaves a location and is unaware of place or time. Critical wandering incidents are expected to increase with the growing prevalence of persons living with dementia worldwide. We investigated the association between demographic, psychopathological, and environmental factors and a history of critical wandering among Medic-Alert subscribers, both with and without dementia.
METHODS
Our retrospective study included data of 25,785 Canadian Medic-Alert subscribers who were aged 40 years or older. We used multivariable logistic regression analysis to examine the associations between a history of critical wandering and dementia status as psychopathological independent variable, controlled by demographic (age, ethnic background, sex at birth, Canadian languages spoken) and environmental (living arrangement, population density) factors.
RESULTS
The overall study sample comprised of mainly older adults (77.4%). Medic-Alert subscribers who were older, male sex at birth, living with dementia, of a minority ethnic group and who did not have proficiency in an official Canadian language had a higher likelihood of a history of critical wandering. Residing in an urban environment, in an institution or with a family member, were environmental factors associated with a higher likelihood of a history of critical wandering.
CONCLUSIONS
People living with dementia experience a higher likelihood of a history of critical wandering compared to those without dementia. Medic-Alert and similar organizations can develop algorithms based on the associated factors that can be used to flag risks of critical wandering. This can inform preventative strategies at the individual and community levels.
Topics: Humans; Male; Female; Retrospective Studies; Aged; Dementia; Aged, 80 and over; Middle Aged; Wandering Behavior; Adult; Risk Factors; Canada
PubMed: 38943089
DOI: 10.1186/s12877-024-05162-3 -
Journal of Neurovirology Jun 2024The Rabies virus is a neurotropic virus that manipulates the natural cell death processes of its host to ensure its own survival and replication. Studies have shown that...
The Rabies virus is a neurotropic virus that manipulates the natural cell death processes of its host to ensure its own survival and replication. Studies have shown that the anti-apoptotic effect of the virus is mediated by one of its protein named, rabies glycoprotein (RVG). Alzheimer's disease (AD) is characterized by the loss of neural cells and memory impairment. We aim to examine whether expression of RVG in the hippocampal cells can shield the detrimental effects induced by Aβ. Oligomeric form of Aβ (oAβ) or vehicle was bilaterally microinjected into the dorsal hippocampus of male Wistar rats. One week later, two μl (10 T.U. /ml) of the lentiviral vector carrying RVG gene was injected into their dorsal hippocampus (post-treatment). In another experiment, the lentiviral vector was microinjected one week before Aβ injection (pre-treatment). One week later, the rat's brain was sliced into cross-sections, and the presence of RVG-expressing neuronal cells was confirmed using fluorescent microscopy. Rats were subjected to assessments of spatial learning and memory as well as passive avoidance using the Morris water maze (MWM) and the Shuttle box apparatuses, respectively. Protein expression of AMPA receptor subunit (GluA1) was determined using western blotting technique. In MWM, Aβ treated rats showed decelerated acquisition of the task and impairment of reference memory. RVG expression in the hippocampus prevented and restored the deficits in both pre- and post- treatment conditions, respectively. It also improved inhibitory memory in the oAβ treated rats. RVG increased the expression level of GluA1 level in the hippocampus. Based on our findings, the expression of RVG in the hippocampus has the potential to enhance both inhibitory and spatial learning abilities, ultimately improving memory performance in an AD rat model. This beneficial effect is likely attributed, at least in part, to the increased expression of GluA1-containing AMPA receptors.
PubMed: 38943023
DOI: 10.1007/s13365-024-01221-y -
GeroScience Jun 2024A growing body of research suggested that there was a link between poor periodontal health and systemic diseases, particularly with the early development of cognitive... (Review)
Review
A growing body of research suggested that there was a link between poor periodontal health and systemic diseases, particularly with the early development of cognitive disorders, dementia, and depression. This is especially true in cases of changes in diet, malnutrition, loss of muscular endurance, and abnormal systemic inflammatory response. Our study aimed to determine the extent of these associations to better target the multi-level healthy aging challenge investigating the impact of periodontal disease on cognitive disorders (cognitive impairment and cognitive decline), dementia, and depression. We conducted a comprehensive literature search up to November 2023 using six different electronic databases. Two independent researchers assessed the eligibility of 7363 records against the inclusion criteria and found only 46 records that met the requirements. The study is registered on PROSPERO (CRD42023485688). We generated random effects pooled estimates and 95% confidence intervals (CI) to evaluate whether periodontal disease increased the risk of the investigated outcomes. The quality assessment revealed moderate quality of evidence and risk of bias. Periodontal disease was found to be associated with both cognitive disorders (relative risk (RR) 1.25, 95% CI 1.11-1.40, in the analysis of cross-sectional studies); cognitive impairment (RR 3.01, 95% CI 1.52-5.95 for longitudinal studies, cognitive decline); and dementia (RR 1.22, 95% CI 1.10-1.36). However, no significant increased risk of depression among subjects with periodontal disease was found (RR 1.07, 95% CI 0.95-1.21). Despite the association with two of the three explored outcomes, the available evidence on periodontal diseases and dementia, cognitive disorders, and depression is controversial due to several limitations. Therefore, further investigations involving validated and standardized tools are required.
PubMed: 38943006
DOI: 10.1007/s11357-024-01243-8 -
Nature Medicine Jun 2024
PubMed: 38942991
DOI: 10.1038/s41591-024-02988-7 -
Nature Aging Jun 2024Investigating the genetic underpinnings of human aging is essential for unraveling the etiology of and developing actionable therapies for chronic diseases. Here, we...
Investigating the genetic underpinnings of human aging is essential for unraveling the etiology of and developing actionable therapies for chronic diseases. Here, we characterize the genetic architecture of the biological age gap (BAG; the difference between machine learning-predicted age and chronological age) across nine human organ systems in 377,028 participants of European ancestry from the UK Biobank. The BAGs were computed using cross-validated support vector machines, incorporating imaging, physical traits and physiological measures. We identify 393 genomic loci-BAG pairs (P < 5 × 10) linked to the brain, eye, cardiovascular, hepatic, immune, metabolic, musculoskeletal, pulmonary and renal systems. Genetic variants associated with the nine BAGs are predominantly specific to the respective organ system (organ specificity) while exerting pleiotropic links with other organ systems (interorgan cross-talk). We find that genetic correlation between the nine BAGs mirrors their phenotypic correlation. Further, a multiorgan causal network established from two-sample Mendelian randomization and latent causal variance models revealed potential causality between chronic diseases (for example, Alzheimer's disease and diabetes), modifiable lifestyle factors (for example, sleep duration and body weight) and multiple BAGs. Our results illustrate the potential for improving human organ health via a multiorgan network, including lifestyle interventions and drug repurposing strategies.
PubMed: 38942983
DOI: 10.1038/s43587-024-00662-8