Alzheimer's Disease Impairment Research Articles

Integrated cerebellar radiomic‐network model for predicting mild cognitive impairment in Alzheimer's disease

AbstractINTRODUCTIONPathological and neuroimaging alterations in the cerebellum of Alzheimer's disease (AD) patients have been documented. However, the role of cerebellum‐derived radiomic and structural connectome modeling in the prediction of AD progression remains unclear.METHODSRadiomic features were extracted from magnetic resonance imaging (MRI) in the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset (n = 1319) and an in‐house dataset (n = 308). Integrated machine learning models were developed to predict the conversion risk of normal cognition (NC) to mild cognitive impairment (MCI) over a 6‐year follow‐up.RESULTSThe cerebellar models outperformed hippocampal models in distinguishing MCI from NC and in predicting transitions from NC to MCI across both cohorts. Key predictors included textural features in the right III and left I and II lobules, and network properties in Vermis I and II, which were associated with cognitive decline in AD.DISCUSSIONCerebellum‐derived radiomic‐network modeling shows promise as a tool for early identification and prediction of disease progression during the preclinical stage of AD.Highlights Altered cerebellar radiomic features and topological networks were identified in the subjects with mild cognitive impairment (MCI). The cerebellar radiomic‐network integrated models outperformed hippocampal models in distinguishing MCI from normal cognition. The cerebellar radiomic model effectively predicts MCI risk and can stratify individuals into distinct risk categories. Specific cerebellar radiomic features are associated with cognitive impairment across various stages of amyloid beta and tau pathology.

Alzheimer's Disease : Current Landscape and Future Directions

Introduction: Alzheimer's disease (AD) is the most prevalent form of dementia, constituting up to 72% of cases, and poses a significant financial burden on global healthcare. The aging population is expected to triple the cost of dementia to over $600 billion in the US alone by 2050. Dementia, a major cause of dependency and dysfunction, accounted for 11.4% of all reported deaths in Britain and Wales in 2022. Recent studies suggest a potential decline in dementia incidence, especially in males in Occident countries, possibly linked to better management of vascular risk. While 89% of dementia costs are attributed to high-income countries, middle and low-income nations face significant challenges in addressing the epidemiology of dementia. The prevalence of AD in developing nations is estimated at 3.4%, varying widely. Women exhibit a 1.17 times higher age-specific global prevalence compared to men, and their age-normalized death rate is also higher, suggesting factors beyond life expectancy contribute to their vulnerability. AD primarily affects individuals aged 75 or older, with 80% of cases in this age group. Acetylcholinesterase inhibitors are commonly used in all stages of dementia, though their efficacy in mild cognitive impairment and prodromal AD is uncertain. Distinguishing AD from depression symptoms can be challenging. The pathological features of AD involve neurofibrillary tangles (NFTs) and senile plaques, leading to neural and synaptic loss. Multiple mechanisms contribute to AD pathogenesis, including amyloid/tau toxicity and oxidative stress. Diagnosis : traditionally relies on clinical criteria, but biomarkers like CSF Aβ and tau proteins, as well as blood-based biomarkers, have shown promise in early detection. Noveltrearment: Promising treatment options include anti-amyloid monoclonal antibodies like aducanumab, lecanemab, and gantenerumab, with varying degrees of success in clinical trials. Donanemab, targeting a specific type of Aβ, has shown significant slowing of mental degradation in early-stage patients.

Tetrahedral framework nucleic acids inhibit Aβ-mediated ferroptosis and ameliorate cognitive and synaptic impairments in Alzheimer’s disease

BackgroundFerroptosis represents a nonapoptotic type of programmed cell death induced by excessive intracellular iron accumulation. Ferroptosis is an essential driver of the pathogenesis of Alzheimer’s disease (AD). Tetrahedral framework nucleic acids (tFNAs) are a novel type of nanoparticle with superior antiapoptotic capacity and excellent biocompatibility. However, the effect of tFNAs on Aβ triggered ferroptosis, cognitive and synaptic impairments in AD remains unknown.MethodsN2a cells were treated with Aβ combined with/without tFNAs. Cell viability and levels of Fe2+, lipid peroxidation, MDA, LDH, and GSH were examined. RNA sequencing was applied to explore dysregulated ferroptosis related genes. Seven-month-old APP/PS1 mice were intranasally administrated with tFNAs for two weeks. Fluorescence imaging was used to detect the tFNAs distribution in the brain. Novel object recognition (NOR) test followed by Morris water maze (MWM) was used to test the learning and memory performance of mice. Golgi staining, Western blot, and immunofluorescence staining were used to examine synaptic plasticity.ResultstFNAs promoted cell viability and GSH levels, reduced the levels of Fe2+, lipid peroxidation, MDA, and LDH in N2a cells treated with Aβ. RNA sequencing revealed that tFNAs reversed the promotive effect of Aβ on ferroptosis driver Atf3 gene and suppressive effect on ferroptosis suppressors Rrm2 and Furin genes. Fluorescence imaging confirmed the brain infiltration of tFNAs. tFNAs rescued synaptic and memory impairments, and ferroptosis in seven-month-old APP/PS1 mice.ConclusionsCollectively, tFNAs inhibited Aβ-mediated ferroptosis and ameliorated cognitive and synaptic impairments in AD mice. tFNAs may serve as novel option to deal with AD.Graphical abstract

Ferroptosis as a Therapeutic Target in Neurodegenerative Diseases: Exploring the Mechanisms and Potential of Treating Alzheimer's Disease and Parkinson's Disease.

Amidst the rising global burden of neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases, there is an urgent need for novel therapeutic strategies to combat these debilitating conditions. These diseases are characterized by progressive neural dysfunction leading to cognitive impairments, for which current therapeutic strategies remain palliative at best. Recently, the discovery of ferroptosis, a novel cell death mode that is different from apoptosis and autophagy, has opened new avenues in the field of cognitive research. With in-depth research on ferroptosis, the clinical significance of iron homeostasis disorders and lipid peroxidation in the occurrence, development, and treatment of neurodegenerative diseases are gradually becoming apparent. This study aims to elucidate the roles of ferroptosis in the context of neurodegeneration and to explore its potential as a therapeutic target. By unraveling the intricate relationship between iron homeostasis disorders, oxidative damage, and lipid metabolism disturbances in these diseases, new intervention targets are revealed. It offers a new dimension to the management of neurocognitive impairments in Alzheimer's and Parkinson's diseases. The implications of these findings extend beyond just Alzheimer's and Parkinson's diseases. They also have relevance with other neurological conditions characterized by oxidative stress and iron dysregulation. This review contributes to increased knowledge of ferroptosis and provides a foundational understanding that could lead to the development of innovative therapeutic strategies. Ultimately, it may alleviate the development of neurodegenerative diseases and improve cognitive function by preventing ferroptosis, which has not only academic significance but also potential clinical significance.

Elevated serum sodium is linked to increased amyloid-dependent tau pathology, neurodegeneration, and cognitive impairment in Alzheimer's disease.

Vascular dysfunction is implicated in the pathophysiology of Alzheimer's disease (AD). While sodium is essential for maintaining vascular function, its role in AD pathology remains unclear. We included 353 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI), assessing serum sodium levels, cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers, magnetic resonance imaging (MRI), and cognitive function. An independent sample (N = 471) with available CSF sodium-related proteins and AD biomarkers was also included. Associations between serum sodium levels and AD pathology, neurodegeneration, and cognition were evaluated using linear regression models. Spearman's correlation analyses assessed the relationships between CSF sodium-related proteins and AD biomarkers. Higher serum sodium levels were associated with increased AD pathology, reduced hippocampal volume, and greater cognitive decline (all p < 0.05). The relationship between serum sodium and amyloid PET was evident in several AD-susceptible brain regions, including the neocortex and limbic system. Individuals with high serum sodium exhibited higher tau pathology, lower hippocampal volume, and more severe cognitive decline per unit increase in amyloid PET compared to those with low serum sodium (all p < 0.05). Among the 14 CSF sodium-related proteins, which were inter-correlated, six were significantly correlated with CSF AD pathology and amyloid PET, while two were correlated with hippocampal volume and cognitive function, with sodium channel subunit beta-2 (SCN2B) and sodium channel subunit beta-3 (SCN3B) showing the strongest correlations. These findings underscore the crucial role of serum sodium in AD progression, highlighting a potential network of sodium dysregulation involved in AD pathology. Targeting sodium may offer a novel therapeutic approach to slowing AD progression, particularly by impeding the progression of amyloid-related downstream events.

Deferiprone in Alzheimer Disease

Interventions that substantially slow neurodegeneration are needed to address the growing burden of Alzheimer disease (AD) to societies worldwide. Elevated brain iron observed in AD has been associated with accelerated cognitive decline and may be a tractable drug target. To investigate whether the brain-permeable iron chelator deferiprone slows cognitive decline in people with AD. This phase 2, double-masked, placebo-controlled randomized clinical trial of 12-month duration was conducted at 9 sites in Australia between August 2, 2018, and April 1, 2023. Patients older than 54 years with amyloid-confirmed mild cognitive impairment or early AD (a Mini-Mental State Examination score of 20 or higher) were screened. Randomization was 2:1 and masked to participants and all study staff. Deferiprone 15 mg/kg twice a day or placebo administered orally for 12 months. The primary outcome was a composite cognitive measure assessed at baseline, 6 months, and 12 months using a neuropsychological test battery (NTB) of memory, executive function, and attention tasks. Secondary outcomes included change in brain iron burden measured by quantitative susceptibility mapping (QSM) magnetic resonance imaging (target engagement), brain volume changes (secondary efficacy measure), and adverse events (safety analysis). Of 167 patients screened for eligibility, 81 were included, with 53 randomly assigned to the deferiprone group (mean [SD] age, 73.0 [8.0] years; 29 male [54.7%]) and 28 to the placebo group (mean [SD] age, 71.6 [7.2] years; 17 male [60.7%]); 54 participants completed the study (7 [25.0%] withdrew from the placebo group and 20 [37.7%] from the deferiprone group). In an intention-to-treat analysis, participants in the deferiprone group showed accelerated cognitive decline on the NTB primary outcome (β for interaction = -0.50; 95% CI, -0.80 to -0.20) compared with placebo (change in NTB composite z score for deferiprone, -0.80 [95% CI, -0.98 to -0.62]; for placebo, -0.30 [95% CI, -0.54 to -0.06]). Secondary analysis revealed that this result was driven by worsening performance on executive function tests. The QSM confirmed that deferiprone decreased iron in the hippocampus compared with placebo (change in hippocampal QSM for deferiprone, -0.36 ppb [95% CI, -0.76 to 0.04 ppb]; for placebo, 0.32 ppb [95% CI, -0.12 to 0.75 ppb]; β for interaction = -0.68 [95% CI, -1.27 to -0.09]). Longitudinal hippocampal volume loss was not affected by deferiprone, but exploratory analysis of other brain regions revealed increased volume loss with deferiprone in frontal areas. The frequency of the adverse effect of neutropenia (4 participants [7.5%] in the deferiprone group) was higher than in similar studies (1.6%-4.4%). These trial findings show that deferiprone 15 mg/kg twice a day decreased hippocampal QSM and accelerated cognitive decline in patients with amyloid-confirmed early AD, suggesting that lowering iron with deferiprone is detrimental to patients with AD. ClinicalTrials.gov Identifier: NCT03234686.

Exploring the potential molecular targets of hydroxymethylbutyrate and glucosamine fortified whey protein drink to modulate sarcopenia and Alzheimer's disease by in silico and in vitro studies

Fortified foods have garnered significant attention as potential therapeutic strategies with less adverse effects and ready accessibility. However, precise formulation is required to optimize their beneficial effects. Our study aimed to unravel the mechanisms of a functional protein beverage, hydroxymethylbutyrate and glucosamine fortified whey protein drink (HG-WPD), as a possible intervention combatting sarcopenia and Alzheimer's disease (AD) by network pharmacology, molecular docking, and experimental assays. This study investigates the molecular pathways through which HG-WPD acts, by combining in silico and in vitro analyses. Our in silico study predicted the important target proteins, including acetylcholinesterase (AChE), matrix metalloproteinase 9 (MMP9), and angiotensin-converting enzyme (ACE), linked to both diseases. The molecular docking analysis showed that hydroxymethylbutyrate and glucosamine exhibited a notable binding affinity to these proteins, therefore suggesting their possible use as multi-target medicinal agents. In vitro studies on C2C12 myotubes showed that HG-WPD reduced dexamethasone-induced cell death highlighting its potential anti-sarcopenic actions. Furthermore, confirming their possible function in reducing cognitive impairment in AD, the antioxidant tests showed great activity of both substances. The results imply that HG-WPD is potentially effective for future therapeutic approaches as a functional food product with dual benefits in combatting sarcopenia and AD.

Is KIBRA polymorphism associated with memory performance and cognitive impairment in Alzheimer's disease?

Genetic variations in a common single nucleotide polymorphism in the ninth intron of the KIBRA gene have been linked to memory performance and risk of Alzheimer's disease (AD). We examined the risk of AD related to presence of KIBRA T allele (versus CC homozygote) and to memory performance. The role of established genetic risk factors APOE ε4 and BDNF Met was also considered. Participants were cognitively healthy individuals (n = 19), participants with amnestic mild cognitive impairment (aMCI) due to AD (n = 99) and AD dementia (n = 37) from the Czech Brain Aging Study. Binary and multinomial logistic regressions compared odds of belonging to a certain diagnostic category and multivariate linear regressions assessed associations with memory. KIBRA T allele was associated with increased AD dementia risk (odds ratio [OR] = 5.98, p = 0.012) compared to KIBRA CC genotype. In APOE ε4 negative individuals, KIBRA T allele was associated with a greater risk of both aMCI due to AD (OR = 6.68, p = 0.038) and AD dementia (OR = 15.75, p = 0.009). In BDNF Met positive individuals, the KIBRA T allele was associated with a greater risk of AD dementia (OR = 10.98, p = 0.050). In AD dementia, the association between KIBRA T allele and better memory performance approached significance (β = 0.42; p = 0.062). The link between possessing the KIBRA T allele and better memory reached statistical significance only among BDNF Met carriers (β = 1.21, p = 0.027). Findings suggest that KIBRA T allele may not fully protect against AD dementia but could potentially delay progression of post-diagnosis cognitive deficits.

Costs of Care in Relation to Alzheimer's Disease Severity in Sweden: A National Registry-Based Cohort Study.

The advancement of diagnostic and therapeutic interventions in early Alzheimer's disease (AD) has demanded the economic evaluation of such interventions. Resource utilization and cost estimates in early AD and, more specifically, the amyloid-positive population are still lacking. We aimed to provide cost estimates in AD in relation to disease severity and compare these with the control population. We also aimed to provide cost estimates for a subset of the AD population with both clinical diagnosis and amyloid-positive confirmation. This was a retrospective longitudinal analysis of resource utilization using data from national registries. A cohort from the national Swedish registry for cognitive/dementia disorders (SveDem) includes all clinically diagnosed AD between 2013 and 2020. The study population included 31,951 people with AD and 63,902 age- and sex-matched controls (1:2). The population was followed until death, the end of December 2020, or 2years from the last clinic visit. Direct medical and social costs were estimated from other national registries. Direct medical costs include costs for medications and inpatient and outpatient clinical visits. Direct social costs include costs for institutionalization, home care, short-term care, support for daytime activities, and housing support. Mean annual costs and 95% confidence intervals were obtained by bootstrapping, presented in 2021 Swedish Krona (SEK) (1 SEK=0.117 USD, 1 SEK=0.0985 EUR in 2021), and disaggregated by AD severity, cost component, sex, age group, and care setting. Mean annual costs for individuals with clinically diagnosed AD were SEK 99,906, SEK 290,972, SEK 479,524, and SEK 795,617 in mild cognitive impairment (MCI), mild, moderate, and severe AD. The mean annual costs for the population with both clinical diagnosis and amyloid-positive AD confirmation (N=5610) were SEK 57,625, SEK 179,153, SEK 333,095, and SEK 668,073 in MCI, mild, moderate, and severe AD, respectively. The mean annual costs were higher in institutionalized than non-institutionalized patients, females than males, and older than younger age groups. Inpatient and drug costs were similar in all AD severity stages, but outpatient costs decreased with AD severity. Costs for institutionalization, home care, support for daytime activities, and short-term care increased with AD severity, whereas the cost of housing support decreased with AD severity. This is the first study estimating annual costs in people with AD from MCI to severe AD, including those for the amyloid-positive population. The study provides cost estimates by AD severity, cost components, care settings, sex, and age groups, allowing health economic modelers to apply the costs based on different model structures and populations.

Melatonin and Hydrogen Sulfide ameliorates cognitive impairments in Alzheimer's disease rat model exposed to chronic mild stress via attenuation of neuroinflamation and inhibition of oxidative stress: Potential role of BDNF

Melatonin and Hydrogen Sulfide ameliorates cognitive impairments in Alzheimer's disease rat model exposed to chronic mild stress via attenuation of neuroinflamation and inhibition of oxidative stress: Potential role of BDNF

Licochalcone A Ameliorates Cognitive Dysfunction in an Alzheimer's Disease Model by Inhibiting Endoplasmic Reticulum Stress-Mediated Apoptosis.

Endoplasmic reticulum (ER) stress-induced neurodegeneration has been considered an underlying cause of Alzheimer disease (AD). Here, we investigated the beneficial effects of licochalcone A (Lico A), a valuable flavonoid of the root of the Glycyrrhiza species, against cognitive impairment in AD by regulating ER stress. The triple transgenic mouse AD models were used and were administrated 5 or 15mg/kg Lico A. Cognitive deficits, Aβ deposition, ER stress, and neuronal apoptosis were determined using Morris Water Maze test, probe trial, immunofluorescence staining, western blotting, and TUNEL staining. To investigate the mechanisms of how Lico A exerts anti-AD effects, primary hippocampal neurons were isolated from the AD model mice and treated with Lico A, salubrinal, an eIF2α phosphatase inhibitor, ML385, a Nrf2 inhibitor, or LY294002, an inhibitor of PI3K. Pharmacokinetics and toxicity of Lico A (15mg/kg) in AD mice were evaluated. We found that Lico A improved cognitive impairment, decreased Aβ plaques, inhibited ER stress, and reduced neuronal apoptosis in the hippocampus and cortex of AD mice. Treatment with Lico A in primary hippocampal neurons exerted the same effects as it did in vivo. Additionally, cotreatment with ML385 or LY294002 significantly impeded the effects of Lico A against ER stress. Moreover, 15mg/kg Lico A had a good bioavailability and low toxicity in AD mice. Our results demonstrated that Lico A ameliorates ER stress-induced neuronal apoptosis by inhibiting PERK/eIF2α/ATF4/CHOP signaling, suggesting the therapeutic potential of Lico A in AD treatment.

Self-Concept in Mild Cognitive Impairment and Mild Dementia due to Alzheimer's Disease Is Affected on Tests of Self-Generated Statements.

Several studies show that Alzheimer's disease (AD) and other neurocognitive disorders have a negative impact on the self and identity formation. Most studies have included persons with mild to moderate dementia, but how AD patients in the earliest phases retrieve information about themselves has only been studied scarcely. The aim of this study was to investigate if persons with mild cognitive impairment (MCI) and mild AD would generate fewer self-related statements than healthy controls. From a memory clinic, we included 17 aMCI patients, 17 patients with mild dementia (AD; MMSE ≥ 24), and 30 healthy controls. Three Events Test and Twenty Statements Test (TST) were applied to all participants. The persons with mild dementia gave significantly fewer statements compared to the controls (p < 0.001) and the aMCI patients (p < 0.01) on TST. Fewer statements were also produced by the aMCI patients compared to the control participants (p < 0.05). Persons from both patient groups produced significantly fewer contextual details compared to the controls on the Three Events Tests. There were significant associations to lexical fluency for both the TST and Three Events Test, but only a limited amount of variance was explained, and the results cannot be explained solely by a fluency effect. The results from this study are in accordance with findings from previous studies demonstrating that mild AD leads to a decline in both autobiographical memories and a diminished sense of self. Further, this study shows that changes in self-concept may occur even in the earliest clinical stages of AD.

Early disruption of entorhinal dopamine in a knock-in model of Alzheimer's disease.

The entorhinal cortex (EC) is a critical brain area for memory formation, while also the region exhibiting the earliest histological and functional alterations in Alzheimer's disease (AD). The EC thus has been long hypothesized as one of the originating brain areas of AD pathophysiology, although circuit mechanisms causing its selective vulnerability remain poorly understood. We found that dopamine neurons projecting their axons to the lateral EC (LEC), critical for memory formation in healthy brains, become dysfunctional and cause memory impairments in early AD brains. In amyloid precursor protein knock-in mice with associative memory impairment, LEC dopamine activity and associative memory encoding of LEC layer 2/3 neurons were disrupted in parallel from the early pathological stage. Optogenetic reactivation of LEC dopamine fibers, as well as L- DOPA treatment, rescued associative learning behavior. These results suggest that dysfunction of LEC-projecting dopamine neurons underlies memory impairment in AD from early stages, pointing to a need for clinical investigation of LEC dopamine in AD patients.

Ten-words recall test: an effective tool to differentiate mild cognitive impairment from subjective cognitive decline.

Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) are stages 2 and 3, respectively, of the Alzheimer's continuum. The Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog's) ten-words recall test is a validated method for the early detection of cognitive impairment in Alzheimer's disease. However, limited studies have investigated its ability to differentiate between SCD and MCI. 203 participants with SCD and 62 participants with MCI underwent multiple neuropsychological assessments. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment-Basic (MOCA-B) served as brief global cognition tests. A binary logistic regression model was used to analyze the potential factors affecting MCI. The accuracy of the ten-words recall test was assessed using the area under the receiver operating characteristic (ROC) and the area under the curve (AUC). The neuropsychological assessment revealed significant differences in the ten-words recall test scores between the SCD (median age 61 years; 70.44% female) and MCI (median age 64 years; 61.29% female) groups (p < 0.001), with the MCI group scoring the highest. Using a cut-off value of 3.15 for the ten-words recall test, sensitivity for distinguishing MCI from SCD reached 87%, while specificity stood at 61% (AUC 0.777, p < 0.001). DeLong's test indicated no statistically significant difference in the ten-words recall test's ability to distinguish between SCD and MCI compared to the total score of ADAS-Cog (AUC 0.833, p) and MMSE (AUC 0.784, p > 0.05). However, a significant difference was observed when compared to MoCA-B (AUC 0.973, p < 0.001). In the population with an education level of ≤ 9 years, the optimal cut-off value for the ten-words recall test was 3.15, yielding a sensitivity of 91% and a specificity of 45% (AUC = 0.674, p = 0.030). In the population with an education level > 9 years, the optimal cut-off value was 3.63, resulting in a sensitivity of 79% and a specificity of 71% (AUC = 0.785, p < 0.001). The ten-words recall test from the ADAS-cog may detect MCI early owing to its simplicity and quick administration. It is an effective and convenient tool for rapidly identifying mild cognitive impairment.

Co-activation of selective nicotinic acetylcholine receptor subtypes is required to reverse hippocampal network dysfunction and prevent fear memory loss in Alzheimer's disease.

Alzheimer's disease (AD) is the most common form of dementia with no known cause and cure. Research suggests that a reduction of GABAergic inhibitory interneurons' activity in the hippocampus by beta-amyloid peptide (Aβ) is a crucial trigger for cognitive impairment in AD via hyperexcitability. Therefore, enhancing hippocampal inhibition is thought to be protective against AD. However, hippocampal inhibitory cells are highly diverse, and these distinct interneuron subtypes differentially regulate hippocampal inhibitory circuits and cognitive processes. Moreover, Aβ unlikely affects all subtypes of inhibitory interneurons in the hippocampus equally. Hence, identifying the affected interneuron subtypes in AD to enhance hippocampal inhibition optimally is conceptually and practically challenging. We have previously found that Aβ selectively binds to two of the three major hippocampal nicotinic acetylcholine receptor (nAChR) subtypes, α7- and α4β2-nAChRs, but not α3β4-nAChRs, and inhibits these two receptors in cultured hippocampal inhibitory interneurons to decrease their activity, leading to hyperexcitation and synaptic dysfunction in excitatory neurons. We have also revealed that co-activation of α7- and α4β2-nAChRs is required to reverse the Aβ-induced adverse effects in hippocampal excitatory neurons. Here, we discover that α7- and α4β2-nAChRs predominantly control the nicotinic cholinergic signaling and neuronal activity in hippocampal parvalbumin-positive (PV+) and somatostatin-positive (SST+) inhibitory interneurons, respectively. Furthermore, we reveal that co-activation of these receptors is necessary to reverse hippocampal network dysfunction and fear memory loss in the amyloid pathology model mice. We thus suggest that co-activation of PV+ and SST+ cells is a novel strategy to reverse hippocampal dysfunction and cognitive decline in AD.

Impaired temporal coding associated with central auditory dysfunction and cognitive impairment in Alzheimer’s disease

Impaired temporal coding associated with central auditory dysfunction and cognitive impairment in Alzheimer’s disease

PFOS sub-chronic exposure selectively activates Aβ clearance pathway to improve the cognitive ability of AD mice

Perfluorooctane sulfonate (PFOS), an emerging persistent organic pollutant, has been controversial in its impact on cognitive functions. Our previous research has confirmed that the sub-chronic PFOS exposure leads to neuronal apoptosis in the cerebral cortex, impairing cognitive functions in normal mice. However, our current study presents a surprising finding: sub-chronic exposure to PFOS effectively reduces cognitive impairments in Alzheimer's disease (AD) mice and significantly retards the disease's progression. Our results indicate that PFOS exposure upregulates the expression level of insulin-degrading enzyme (IDE) in the prefrontal cortex (PFC) of AD mice, thereby selectively enhancing the amyloid-beta (Aβ) clearance pathway without affecting the Aβ production. Moreover, PFOS exposure inhibits microglial proliferation and reduces inflammatory cytokines levels in the PFC of AD mice, providing further supporting for the pivotal role of IDE in attenuating AD progression under PFOS exposure. Collectively, our study is the first to demonstrate that sub-chronic PFOS exposure can alleviates cognitive impairments in AD pathology, with the IDE-mediated Aβ clearance pathway potentially playing a critical role.

Avicularin inhibits ferroptosis and improves cognitive impairments in Alzheimer's disease by modulating the NOX4/Nrf2 axis

BackgroundAlzheimer's disease (AD) is a widespread neurodegenerative disorder for which effective therapies remain elusive, primarily due to the complexity of its underlying pathophysiology. In recent years, natural products have gained attention for their therapeutic potential in AD, owing to their multi-targeted actions and low toxicity profiles. Avicularin (Avi), a flavonoid derived from the peels of Zanthoxylum bungeanum Maxim., has shown promise as an anti-AD agent. However, the specific mechanisms by which Avi mitigates oxidative stress and inhibits ferroptosis in AD models remain insufficiently understood. Further investigation is required to elucidate its therapeutic potential in these pathways. PurposeTherefore, this study aims to elucidate the neuroprotective effects of Avi in AD by investigating its impact on the NOX4/Nrf2 signaling pathway, as well as its role in modulating oxidative stress and ferroptosis. MethodsIn this study, an in vitro H2O2-induced oxidative stress model in SH-SY5Y cells was utilized to evaluate the pharmacological efficacy and underlying mechanisms of Avi. Molecular docking, CETSA and BLI assays were conducted to identify potential molecular targets of Avi. Additionally, in vivo models, including scopolamine (SCOP)-induced and APP/PS1 transgenic mice, were employed to assess the cognitive effects of Avi and further explore its associated molecular mechanisms. ResultsOur study demonstrates that Avi effectively attenuates H2O2-induced toxicity in SH-SY5Y cells by reducing apoptosis and enhancing cellular antioxidant defenses. This neuroprotective effect is mediated through the inhibition of NOX4 and the promotion of Nrf2 nuclear translocation. Furthermore, Avi improves cognitive function and mitigates ferroptosis in both SCOP-induced and APP/PS1 transgenic mouse models of AD. ConclusionAvi emerges as an effective neuroprotective agent against AD, offering a promising therapeutic approach by targeting the NOX4/Nrf2 signaling axis to alleviate oxidative stress and ferroptosis.

Association of dementia with impaired kidney function and plasma biomarkers: A population-based study.

Emerging evidence has linked impaired kidney function with dementia in older adults, but the neuropathological pathways underlying their association remain poorly understood. We sought to examine the relationships of kidney function with dementia and plasma biomarkers in a Chinese rural population. This population-based study used data from the baseline examination of the Multimodal Interventions to Delay Dementia and Disability in rural China (MIND-China) cohort (March-September 2018; n = 5715). Kidney function was assessed using estimated glomerular filtration rate (eGFR) based on serum creatinine level. Dementia, Alzheimer's disease (AD) and vascular dementia (VaD) were diagnosed according to the international criteria. Plasma biomarkers were measured using the SIMOA platform in a subsample (n = 1446). Data were analyzed using logistic, general linear, and mediation models. Of the 5715 participants, 306 were diagnosed with dementia, including 195 with AD and 100 with VaD. Impaired kidney function (eGFR <60 vs. ≥90 mL/min/1.73 m2) was associated with multivariable-adjusted odds ratios of 2.24 (95% confidence interval [CI] 1.44-3.46) for all-cause dementia, 1.85 (1.07-3.18) for AD, and 2.49 (1.16-5.22) for VaD. In the biomarker subsample, impaired kidney function was significantly associated with higher plasma amyloid-β (Aβ)40 (β-coefficient = 54.36, 95% CI 43.34-65.39), Aβ42 (β-coefficient = 3.14, 95% CI 2.42-3.86), neurofilament light chain (β-coefficient = 10.62, 95% CI 5.62-15.62), and total tau (β-coefficient = 0.68, 95% CI 0.44-0.91), and a lower Aβ42/Aβ40 ratio (β-coefficient = -4.11, 95% CI -8.08 to -0.14). The mediation analysis showed that plasma total tau significantly mediated 21.76% of the association between impaired kidney function and AD (p < 0.05). Impaired kidney function is associated with dementia and plasma biomarkers among rural-dwelling older Chinese adults, and the association with AD is partly mediated by plasma biomarkers for neurodegeneration.

Language abnormalities in Alzheimer's disease indicate reduced informativeness.

This study aims to elucidate the cognitive underpinnings of language abnormalities in Alzheimer's Disease (AD) using a computational cross-linguistic approach and ultimately enhance the understanding and diagnostic accuracy of the disease. Computational analyses were conducted on language samples of 156 English and 50 Persian speakers, comprising both AD patients and healthy controls, to extract language indicators of AD. Furthermore, we introduced a machine learning-based metric, Language Informativeness Index (LII), to quantify empty speech. Despite considerable disparities in surface structures between the two languages, we observed consistency across language indicators of AD in both English and Persian. Notably, indicators of AD in English resulted in a classification accuracy of 90% in classifying AD in Persian. The substantial degree of transferability suggests that the language abnormalities of AD do not tightly link to the surface structures specific to English. Subsequently, we posited that these abnormalities stem from impairments in a more universal aspect of language production: the ability to generate informative messages independent of the language spoken. Consistent with this hypothesis, we found significant correlations between language indicators of AD and empty speech in both English and Persian. The findings of this study suggest that language impairments in AD arise from a deficit in a universal aspect of message formation rather than from the breakdown of language-specific morphosyntactic structures. Beyond enhancing our understanding of the psycholinguistic deficits of AD, our approach fosters the development of diagnostic tools across various languages, enhancing health equity and biocultural diversity.