Tirzepatide shows neuroprotective effects via regulating brain glucose metabolism in APP/PS1 mice.

Tirzepatide (LY3298176), a GLP-1 and GIP receptor agonist, is fatty-acid-modified and 39-amino acid linear peptide, which ameliorates learning and memory impairment in diabetic rats. However, the specific molecular mechanism remains unknown. In the present study, we investigated the role of tirzepatide in the neuroprotective effects in Alzheimer's disease (AD) model mice. Tirzepatide was administrated intraperitoneal (i.p.) APP/PS1 mice for 8 weeks with at 10 nmol/kg once-weekly, it significantly decreased the levels of GLP-1R, and GFAP protein expression and amyloid plaques in the cortex, it also lowered neuronal apoptosis induced by amyloid-ß (Aß), but did not affect the anxiety and cognitive function in APP/PS1 mice. Moreover, tirzepatide reduced the blood glucose levels and increased the mRNA expression of GLP-1R, SACF1, ATF4, Glu2A, and Glu2B in the hypothalamus of APP/PS1 mice. Tirzepatide increased the mRNA expression of glucose transporter 1, hexokinase, glucose-6-phosphate dehydrogenase, and phosphofructokinase in the cortex. Lastly, tirzepatide improved the energetic metabolism by regulated reactive oxygen species production and mitochondrial membrane potential caused by Aß, thereby decreasing mitochondrial function and ATP levels in astrocytes through GLP-1R. These results provide valuable insights into the mechanism of brain glucose metabolism and mitochondrial function of tirzepatide, presenting potential strategies for AD treatment.

Disentangling brain atrophy heterogeneity in Alzheimer's disease: A deep self-supervised approach with interpretable latent space.

Alzheimer's disease (AD) is heterogeneous, but existing methods for capturing this heterogeneity through dimensionality reduction and unsupervised clustering have limitations when it comes to extracting intricate atrophy patterns. In this study, we propose a deep learning based self-supervised framework that characterizes complex atrophy features using latent space representation. It integrates feature engineering, classification, and clustering to synergistically disentangle heterogeneity in Alzheimer's disease. Through this representation learning, we trained a clustered latent space with distinct atrophy patterns and clinical characteristics in AD, and replicated the findings in prodromal Alzheimer's disease. Moreover, we discovered that these clusters are not solely attributed to subtypes but also reflect disease progression in the latent space, representing the core dimensions of heterogeneity, namely progression and subtypes. Furthermore, longitudinal latent space analysis revealed two distinct disease progression pathways: medial temporal and parietotemporal pathways. The proposed approach enables effective latent representations that can be integrated with individual-level cognitive profiles, thereby facilitating a comprehensive understanding of AD heterogeneity.

APOE, Immune Factors, Sex, and Diet Interact to Shape Brain Networks in Mouse Models of Aging.

Alzheimer's disease (AD) presents complex challenges due to its multifactorial nature, poorly understood etiology, and late detection. The mechanisms through which genetic, fixed and modifiable risk factors influence susceptibility to AD are under intense investigation, yet the impact of unique risk factors on brain networks is difficult to disentangle, and their interactions remain unclear. To model multiple risk factors including APOE genotype, age, sex, diet, and immunity we leveraged mice expressing the human APOE and NOS2 genes, conferring a reduced immune response compared to mouse Nos2. Employing graph analyses of brain connectomes derived from accelerated diffusion-weighted MRI, we assessed the global and local impact of risk factors in the absence of AD pathology. Aging and a high-fat diet impacted extensive networks comprising AD-vulnerable regions, including the temporal association cortex, amygdala, and the periaqueductal gray, involved in stress responses. Sex impacted networks including sexually dimorphic regions (thalamus, insula, hypothalamus) and key memory-processing areas (fimbria, septum). APOE genotypes modulated connectivity in memory, sensory, and motor regions, while diet and immunity both impacted the insula and hypothalamus. Notably, these risk factors converged on a circuit comprising 63 of 54,946 total connections (0.11% of the connectome), highlighting shared vulnerability amongst multiple AD risk factors in regions essential for sensory integration, emotional regulation, decision making, motor coordination, memory, homeostasis, and interoception. These network-based biomarkers hold translational value for distinguishing high-risk versus low-risk participants at preclinical AD stages, suggest circuits as potential therapeutic targets, and advance our understanding of network fingerprints associated with AD risk. Significance Statement: Current interventions for Alzheimer's disease (AD) do not provide a cure, and are delivered years after neuropathological onset. Addressing the impact of risk factors on brain networks holds promises for early detection, prevention, and revealing putative therapeutic targets at preclinical stages. We utilized six mouse models to investigate the impact of factors, including APOE genotype, age, sex, immunity, and diet, on brain networks. Large structural connectomes were derived from high resolution compressed sensing diffusion MRI. A highly parallelized graph classification identified subnetworks associated with unique risk factors, revealing their network fingerprints, and a common network composed of 63 connections with shared vulnerability to all risk factors. APOE genotype specific immune signatures support the design of interventions tailored to risk profiles.

A Comprehensive Head-to-Head Comparison of Key Plasma Phosphorylated Tau 217 Biomarker Tests.

Plasma phosphorylated-tau 217 (p-tau217) is currently the most promising biomarkers for reliable detection of Alzheimer's disease (AD) pathology. Various p-tau217 assays have been developed, but their relative performance is unclear. We compared key plasma p-tau217 tests using cross-sectional and longitudinal measures of amyloid-ß (Aß)-PET, tau-PET, and cognition as outcomes, and benchmarked them against cerebrospinal fluid (CSF) biomarker tests. Samples from 998 individuals (mean[range] age 68.5[20.0-92.5], 53% female) from the Swedish BioFINDER-2 cohort were analyzed. Plasma p-tau217 was measured with mass spectrometry (MS) assays (the ratio between phosphorylated and non-phosphorylated [%p-tau217WashU]and ptau217WashU) as well as with immunoassays (p-tau217Lilly, p-tau217Janssen, p-tau217ALZpath). CSF biomarkers included p-tau217Lilly, and the FDA-approved p-tau181/Aß42Elecsys and p-tau181Elecsys. All plasma p-tau217 tests exhibited high ability to detect abnormal Aß-PET (AUC range: 0.91-0.96) and tau-PET (AUC range: 0.94-0.97). Plasma %p-tau217WashU had the highest performance, with significantly higher AUCs than all the immunoassays (P diff<0.007). For detecting Aß-PET status, %p-tau217WashU had an accuracy of 0.93 (immunoassays: 0.83-0.88), sensitivity of 91% (immunoassays: 84-87%), and a specificity of 94% (immunoassays: 85-89%). Among immunoassays, p-tau217Lilly and plasma p-tau217ALZpath had higher AUCs than plasma p-tau217Janssen for Aß-PET status (P diff<0.006), and p-tau217Lilly outperformed plasma p-tau217ALZpath for tau-PET status (P diff=0.025). Plasma %p-tau217WashU exhibited higher associations with all PET load outcomes compared to immunoassays; baseline Aß-PET load (R2: 0.72; immunoassays: 0.47-0.58; Pdiff<0.001), baseline tau-PET load (R2: 0.51; immunoassays: 0.38-0.45; Pdiff<0.001), longitudinal Aß-PET load (R2: 0.53; immunoassays: 0.31-0.38; Pdiff<0.001) and longitudinal tau-PET load (R2: 0.50; immunoassays: 0.35-0.43; Pdiff<0.014). Among immunoassays, plasma p-tau217Lilly was more strongly associated with Aß-PET load than plasma p-tau217Janssen (P diff<0.020) and with tau-PET load than both plasma p-tau217Janssen and plasma p-tau217ALZpath (all P diff<0.010). Plasma %p-tau217 also correlated more strongly with baseline cognition (Mini-Mental State Examination[MMSE]) than all immunoassays (R2 %p-tau217WashU: 0.33; immunoassays: 0.27-0.30; P diff<0.024). The main results were replicated in an external cohort from Washington University in St Louis (n =219). Finally, p-tau217Nulisa showed similar performance to other immunoassays in subsets of both cohorts. In summary, both MS- and immunoassay-based p-tau217 tests generally perform well in identifying Aß-PET, tau-PET, and cognitive abnormalities, but %p-tau217WashU performed significantly better than all the examined immunoassays. Plasma %p-tau217 may be considered as a stand-alone confirmatory test for AD pathology, while some immunoassays might be better suited as triage tests where positive results are confirmed with a second test.

Psychological distress among family caregivers of persons with Alzheimer's disease and related dementias in Uganda.

BACKGROUND: Alzheimer's disease and related dementias (ADRD) present growing global health challenges, especially in aging populations, such as Uganda. In Uganda, familial caregiving, predominantly undertaken by female relatives, is the primary form of support provided to patients with ADRD. Cultural stigma around dementia and limited access to support services amplify caregivers' challenges. This study examined psychological distress, depression, and quality of life (QoL) among family caregivers of patients with ADRD in Wakiso District, Uganda. METHODS: This cross-sectional study involved 90 caregivers from three sub-counties in Wakiso, selected through purposive sampling to capture diverse experiences. Participants included caregivers aged 18 years and older who were knowledgeable and had cared for a person with ADRD for not less than six months, with those providing more than 70% of physical care being prioritised. Data were collected using the Kessler Psychological Distress Scale, the Caregiver Dementia Quality of Life Measurement Scale, and the Center for Epidemiologic Studies Depression Scale, with an 80% response rate achieved through local collaboration. The statistical analyses focused on psychological distress, QoL, and depression. RESULTS: The study included 82.2% females and 17.8% males, with a median age of 52 years for females and 35 years, respectively. Females were more likely to be single or widowed, whereas males were more likely to be married. The study revealed a high prevalence of psychological distress and depression among caregivers (64.4%) regardless of sex. The analysis indicated that having children was a significant predictor of better QoL (OR 3.04, 95% CI 1.79-5.66, p = 0.034) and a lower risk of depression (OR 0.10, 95% CI 0.01-0.86, p = 0.036). No other sociodemographic factors were significantly associated with health outcomes across the models. CONCLUSION: Our findings revealed a heavy burden of psychological distress and depression among Ugandan caregivers of patients with ADRD, highlighting the need for structured support systems, including mental health services and gender-responsive interventions in low-resource settings.

The interactive effects of different exercises and hawthorn consumption on the pain threshold of TMT-induced Alzheimer male rats.

Exercise increases the pain threshold in healthy people. However, the pain threshold modulation effect of exercise and hawthorn is unclear because of its potential benefits in people with persistent pain, including those with Alzheimer's disease. Accordingly, after the induction of Alzheimer's disease by trimethyl chloride, male rats with Alzheimer's disease were subjected to a 12-week training regimen consisting of resistance training, swimming endurance exercises, and combined exercises. In addition, hawthorn extract was orally administered to the rats. Then, their pain threshold was evaluated using three Tail-flick, Hot-plate, and Formalin tests. Our results showed that Alzheimer's decreased the pain threshold in all three behavioral tests. Combined exercise with hawthorn consumption had the most statistically significant effect on Alzheimer's male rats' pain threshold in all three experiments. A combination of swimming endurance and resistance exercises with hawthorn consumption may modulate hyperalgesia in Alzheimer's rats. Future studies need to determine the effects of these factors on the treatment and/or management of painful conditions.

Harnessing the Therapeutic Potential of Peptides for Synergistic Treatment of Alzheimer's Disease by Targeting Aß Aggregation, Metal-Mediated Aß Aggregation, Cholinesterase, Tau Degradation, and Oxidative Stress.

Alzheimer's disease (AD) is a progressive multifaceted neurodegenerative disease and remains a formidable global health challenge. The current medication for AD gives symptomatic relief and, thus, urges us to look for alternative disease-modifying therapies based on a multitarget directed approach. Looking at the remarkable progress made in peptide drug development in the last decade and the benefits associated with peptides, they offer valuable chemotypes [multitarget directed ligands (MTDLs)] as AD therapeutics. This review recapitulates the current developments made in harnessing peptides as MTDLs in combating AD by targeting multiple key pathways involved in the disease's progression. The peptides hold immense potential and represent a convincing avenue in the pursuit of novel AD therapeutics. While hurdles remain, ongoing research offers hope that peptides may eventually provide a multifaceted approach to combat AD.

Preparation and Characterization of Zn(II)-Stabilized Aß42 Oligomers.

Aß oligomers are being investigated as cytotoxic agents in Alzheimer's disease (AD). Because of their transient nature and conformational heterogeneity, the relationship between the structure and activity of these oligomers is still poorly understood. Hence, methods for stabilizing Aß oligomeric species relevant to AD are needed to uncover the structural determinants of their cytotoxicity. Here, we build on the observation that metal ions and metabolites have been shown to interact with Aß, influencing its aggregation and stabilizing its oligomeric species. We thus developed a method that uses zinc ions, Zn(II), to stabilize oligomers produced by the 42-residue form of Aß (Aß42), which is dysregulated in AD. These Aß42-Zn(II) oligomers are small in size, spanning the 10-30 nm range, stable at physiological temperature, and with a broad toxic profile in human neuroblastoma cells. These oligomers offer a tool to study the mechanisms of toxicity of Aß oligomers in cellular and animal AD models.

Clinically feasible automated MRI volumetry of the brain as a prognostic marker in subjective and mild cognitive impairment.

Background/aims: The number of patients suffering from cognitive decline and dementia increases, and new possible treatments are being developed. Thus, the need for time efficient and cost-effective methods to facilitate an early diagnosis and prediction of future cognitive decline in patients with early cognitive symptoms is becoming increasingly important. The aim of this study was to evaluate whether an MRI based software, NeuroQuant® (NQ), producing volumetry of the hippocampus and whole brain volume (WBV) could predict: (1) conversion from subjective cognitive decline (SCD) at baseline to mild cognitive impairment (MCI) or dementia at follow-up, and from MCI at baseline to dementia at follow-up and (2) progression of cognitive and functional decline defined as an annual increase in the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) score. Methods: MRI was performed in 156 patients with SCD or MCI from the memory clinic at Oslo University Hospital (OUH) that had been assessed with NQ and had a clinical follow-up examination. Logistic and linear regression analyses were performed with hippocampus volume and WBV as independent variables, and conversion or progression as dependent variables, adjusting for demographic and other relevant covariates including Mini-Mental State Examination-Norwegian Revised Version score (MMSE-NR) and Apolipoprotein E ɛ4 (APOE ɛ4) carrier status. Results: Hippocampus volume, but not WBV, was associated with conversion to MCI or dementia, but neither were associated with conversion when adjusting for MMSE-NR. Both hippocampus volume and WBV were associated with progression as measured by the annual change in CDR-SB score in both unadjusted and adjusted analyses. Conclusion: The results indicate that automated regional MRI volumetry of the hippocampus and WBV can be useful in predicting further cognitive decline in patients with early cognitive symptoms.

Personalized goals of people living with dementia and family carers: A content analysis of goals set within an individually tailored psychosocial intervention trial.

Introduction: Person-centered goals capture individual priorities in personal contexts. Goal Attainment Scaling (GAS) has been used in drug trials involving people living with dementia (PLWD) but GAS has been characterized as difficult to incorporate into trials and clinical practice. We used GAS in a trial of New Interventions for Independence in Dementia Study (NIDUS)-family, a manualized care and support intervention, as the primary outcome and to tailor the interventions to goals set. We aimed to assess the feasibility and content of baseline goal-setting. Methods: We developed training for nonclinical facilitators to set individualized GAS goals remotely with PLWD and family carer dyads, or carers alone, in the intervention trial, during the COVID-19 pandemic. A qualitative content analysis of the goals set explored participants' priorities and unmet needs, to consider how existing GAS goal domains might be extended in a psychosocial intervention trial context. Results: Eleven facilitators were successfully trained to set and score GAS goals. A total of 313/328 (95%) participants were able to collaboratively set three to five goals with the facilitators. Of these, 302 randomized participating dyads set 1043 (mean 3.5, range 3 to 5) goals. We deductively coded 719 (69%) goals into five existing GAS domains (mood, behavior, self-care, cognition, and instrumental activities of daily living); 324 (31%) goals were inductively coded into four new domains: carer break, carer mood, carer behavior, and carer sleep. The most frequently set goals pertained to social support. There was little variation in types of goals set based on the context of who set them or level of pandemic restrictions in place. Discussion: It is feasible for people without clinical training to set GAS holistic goals for PLWD and family carers in the community. GAS has potential to facilitate personalization of care and support interventions, such as NIDUS-family, and facilitate the roll out of more personalized care. Highlights: Goal Attainment Scaling (GAS) can capture meaningful priorities of people with dementia and their family carers.A psychosocial intervention RCT used GAS as the primary outcome measure and goals were set collaboratively by non-clinically trained facilitators.The findings underscore the feasibility of using GAS as an outcome measure with this population.The content analysis findings unveiled the diversity in experiences and priorities of the study participants.GAS has the potential to support the implementation of more person-centred approaches to dementia care.

Brain inflammation co-localizes highly with tau in mild cognitive impairment due to early-onset Alzheimer's disease.

Brain inflammation, with an increased density of microglia and macrophages, is an important component of Alzheimer's disease (AD) and a potential therapeutic target. However, it is incompletely characterized, particularly in patients whose disease begins before the age of 65 years and, thus, have few co-pathologies. Inflammation has been usefully imaged with translocator protein (TSPO) positron emission tomography (PET), but most inflammation PET tracers cannot image subjects with a low-binder TSPO rs6971 genotype. In an important development, participants with any TSPO genotype can be imaged with a novel tracer, [11C]ER176, that has a high binding potential and a more favorable metabolite profile than other TSPO tracers currently available. We applied [11C]ER176 to detect brain inflammation in mild cognitive impairment (MCI) caused by early-onset AD. Furthermore, we sought to correlate the brain localization of inflammation, volume loss, elevated Aß and tau. We studied brain inflammation in 25 patients with early-onset amnestic MCI (average age 59 ± 4.5 years, 10 women) and 23 healthy controls (average age 65 ± 6.0 years, 12 women), both groups with a similar proportion of all three TSPO-binding affinities. [11C]ER176 total distribution volume (VT), obtained with an arterial input function, was compared across patients and controls using voxel-wise and region-wise analyses. In addition to inflammation PET, most MCI patients had Aß (n=23), and tau PET (n=21). For Aß and tau tracers, standard uptake value ratios (SUVRs) were calculated using cerebellar grey matter as region of reference. Regional correlations among the three tracers were determined. Data were corrected for partial volume effect. Cognitive performance was studied with standard neuropsychological tools. In MCI caused by early-onset AD, there was inflammation in the default network, reaching statistical significance in precuneus and lateral temporal and parietal association cortex bilaterally, and in the right amygdala. Topographically, inflammation co-localized most strongly with tau (r= 0.63 ± 0.24). This correlation was higher than the co-localization of Aß with tau (r= 0.55±0.25) and of inflammation with Aß (0.43±0.22). Inflammation co-localized least with atrophy (-0.29±0.26). These regional correlations could be detected in participants with any of the three rs6971 TSPO polymorphisms. Inflammation in AD-related regions correlated with impaired cognitive scores. Our data highlight the importance of inflammation, a potential therapeutic target, in the AD process. Furthermore, they support the notion that, as shown in experimental tissue and animal models, the propagation of tau in humans is associated with brain inflammation.

Telemedicine Utilization Among Residents With Alzheimer Disease and Related Dementia: Association With Nursing Home Characteristics.

OBJECTIVE: To examine telemedicine use among nursing home (NH) residents with Alzheimer disease and related dementias (ADRD) and the associations with NH characteristics. DESIGN: Observational study. SETTING AND PARTICIPANTS: 2020-2021 Minimum Data Set 3.0, Medicare datasets, and Nursing Home Compare data were linked. A total of 10,810 NHs were identified. METHODS: The outcome variable was the percentage of ADRD residents who used telemedicine in an NH in a quarter. The main independent variables were NH racial and ethnic compositions (ie, percentages of Black and Hispanic residents) and NH rurality. A set of linear models with NH random effects were estimated. The analysis was stratified by COVID-19 pandemic stages, including the beginning of the pandemic (second quarter of 2020 [2020 Q2]), before and after the widespread of the COVID-19 vaccine (ie, 2020 Q3-2021 Q1 and 2021 Q2-2021 Q4). RESULTS: The proportion of ADRD residents in NHs who had telemedicine use declined from 35.0% in 2020 Q2 to 9.3% in 2021 Q4. After adjusting for other NH characteristics, NHs with a high proportion of Hispanic residents were 2.7 percentage points more likely to use telemedicine for ADRD residents than those with a low proportion during 2021 Q2-2021 Q4 (P < .001), whereas NHs with a high proportion of Black residents were 1.5 percentage points less likely to use telemedicine than those with a low proportion (P < .01). Additionally, compared with metropolitan NHs, rural NHs were 6.4 percentage points less likely to use telemedicine in 2020 Q2 (P < .001), but 5.9 percentage points more likely to use telemedicine during 2021 Q2-2021 Q4 (P < .001). We also detected the relationship between telemedicine use and other NH characteristics, such as NH quality, staffing level, and Medicaid-pay days. CONCLUSIONS AND IMPLICATIONS: The proportion of ADRD residents in NHs who had telemedicine use decreased during the pandemic. Telemedicine could improve health care access for NHs with a high proportion of Hispanic residents and NHs in remote areas. Future studies should investigate how telemedicine use affects the health outcomes of NH residents with ADRD.

Alleviating neuronal inflammation induced by Aß42 in SH-SY5Y through interaction with polysialic acid-oligomannuronate conjugate.

Amyloid beta (Aß) aggregation is one of the distinctive pathological hallmarks of Alzheimer's disease (AD). Therefore, the development of effective inhibitors against Aß aggregate formation offers great promise for the treatment of AD. In this study, we designed a novel negatively charged functionalized conjugate aimed at inhibiting Aß42 aggregation and attenuating neurotoxicity by grafting polysialic acid with mannuronate oligosaccharide, a biocompatible glycan extracted from seaweeds, designated as polysialic acid-mannan conjugate (PSA-MOS). ThT, biological microscopy, TEM and CD confirmed the inhibition of Aß42 aggregation by PSA-MOS, as well as its ability to inhibit the conformational transition of Aß42 to ß-sheet. CCK-8 assay demonstrated that PSA-MOS was not cytotoxic to SH-SY5Y (p < 0.05) and promoted cell proliferation. In the Aß42-induced SH-SY5Y injury models, PSA-MOS dose-dependently ameliorated cytotoxicity (p < 0.0001) and significantly reduced the levels of inflammatory factors of IL-1ß (p < 0.0001), IL-6 (p < 0.0001) and TNF-α (p < 0.05). MD simulations demonstrated that PSA-MOS effectively impeded the α-helix to ß-sheet transition of the Aß42 monomer via electrostatic interactions with its CTR and NTR regions. These findings demonstrate the therapeutic potential of PSA-MOS as promising glycoconjugate for the treatment of AD.

Somatostatin: Linking Cognition and Alzheimer's Disease to Therapeutic Targeting.

Over four decades of research support the link between Alzheimer's disease (AD) and somatostatin (somatotropin-releasing inhibitory factor, SRIF). SRIF and SRIF-expressing neurons play an essential role in brain function, modulating hippocampal activity and memory formation. Loss of SRIF and SRIF-expressing neurons in the brain rests at the center of a series of interdependent pathological events driven by amyloid-beta peptide (Aß), culminating in cognitive decline and dementia. The connection between the SRIF and AD further extends to the neuropsychiatric symptoms, seizure activity, and inflammation. Whereas, preclinical AD investigations show SRIF or SRIF-receptor agonist administration capable of enhancing cognition. SRIF receptor subtype-4 activation in particular presents unique attributes, with the potential to mitigate learning and memory decline, reduce comorbid symptoms, and enhance enzymatic degradation of Aß in the brain. Here we review the links between SRIF and AD, along with the therapeutic implications. Significance Statement Somatostatin and somatostatin-expressing neurons in the brain are extensively involved in cognition. Loss of somatostatin and somatostatin-expressing neurons in Alzheimer's disease rests at the center of a series of interdependent pathological events contributing to cognitive decline and dementia. Targeting somatostatin mediated processes has significant therapeutic potential for the treatment of Alzheimer's disease.

Care partner-informed meaningful change thresholds for the Clinical Dementia Rating-Sum of Boxes for trials of early Alzheimer's disease.

INTRODUCTION: Consensus definitions of meaningful within-patient change (MWPC) on the Clinical Dementia Rating-Sum of Boxes (CDR-SB) are needed. Existing estimates use clinician-rated anchors in clinically diagnosed Alzheimer's disease (AD) populations. Incorporating the care partner perspective offers important insights, and evaluating biomarker-confirmed cohorts aligns estimates with ongoing trials. METHODS: Anchor-based analyses were conducted to evaluate MWPC on the CDR-SB in early AD (Tauriel; NCT03289143) using Caregiver Global Impression of Change in memory or daily activities. RESULTS: Across time points and anchors, mean CDR-SB changes associated with the "somewhat worse" category ranged from 1.50 to 2.12 in early AD, 1.07 to 2.06 in mild cognitive impairment-AD, and 1.79 to 2.25 in mild AD. DISCUSSION: The proposed ranges are appropriate to define meaningful progression on the CDR-SB in similar cohorts and support the interpretation of treatment benefit through MWPC analyses. Thresholds should be calibrated to the context of use; lower/higher thresholds may be applicable in studies of earlier/later disease over shorter/longer durations. HIGHLIGHTS: Within-patient CDR-SB change thresholds are provided using caregiver-rated anchors. 1.5 to 2.5 points may be an appropriate range in early AD trials of similar durations. Cumulative distribution function plots illustrate the benefit of a given treatment. When selecting thresholds, the target population and study design should be considered.

Alterations of resting-state network dynamics in Alzheimer's disease based on leading eigenvector dynamics analysis.

Alzheimer's disease (AD) is a neurodegenerative disease, and mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia. Early detection of MCI can help slow down the progression of AD. At present, there are few studies exploring the characteristics of abnormal dynamic brain activity in AD. This article uses a method called Leading Eigenvector Dynamics Analysis (LEiDA) to study resting-state functional magnetic resonance imaging (rs-fMRI) data of AD, MCI, and cognitively normal (CN) participants. By identifying repetitive states of phase coherence, inter group differences in brain dynamic activity indicators are examined. And the neurobehavioral scales were used to assess the relationship between abnormal dynamic activities and cognitive function. The results showed that in the indicators of occurrence probability and lifetime, the globally synchronized state of the patient group decreased. The activity state of the limbic regions significantly detected the difference between AD and the other two groups. Compared to CN, AD and MCI have varying degrees of increase in default and visual regions activity states. In addition, in the analysis related to the cognitive scales, it was found that individuals with poorer cognitive abilities were less active in the globally synchronized state, and more active in limbic regions activity state and visual regions activity state. Taken together, these findings reveal abnormal dynamic activity of resting-state networks in patients with AD and MCI, provide new insights into the dynamic analysis of brain networks, and contribute to a deeper understanding of abnormal spatial dynamic patterns in AD patients.

The Bayesian approach for real­world implementation of plasma p­tau217 in tertiary care memory clinics in Thailand.

INTRODUCTION: Plasma phosphorylated tau (p-tau)217 is a promising biomarker for Alzheimer's disease (AD) diagnosis, but its clinical implementation remains challenging. We propose a strategy based on Bayes' theorem and test it in real-life memory clinics. METHODS: Memory clinic patients were evaluated by neurocognitive specialists for prespecified diagnosis and subsequently underwent blood collection for p-tau217, cerebrospinal fluid, or amyloid positron emission tomography. Using cross-validation, the Bayesian approach (pretest probability × individualized likelihood ratio) was compared to other models for AD diagnosis. RESULTS: The Bayesian strategy demonstrated an area under the receiver operating characteristic curve (AUC) of 0.98 (95% confidence interval [CI]: 0.96-1.0), significantly outperforming multivariable logistic regression (p-tau217, age, apolipoprotein E; AUC 0.95, p = 0.024) and p-tau217 alone (AUC = 0.94, p = 0.007). When applying the two-threshold approach, the Bayesian strategy yielded an accuracy of 0.94 (95% CI: 0.88-1.0) without requiring confirmatory tests in 62.9% of the iterations. DISCUSSION: The Bayesian strategy offers an effective and flexible approach to address the limitations of plasma p-tau217 in clinical practice. HIGHLIGHTS: Incorporating pretest probability into the interpretation of plasma phosphorylated tau (p-tau)217 improves the diagnostic performance significantly. The strategy could obviate the need for confirmatory testing in most of the patients. Plasma p-tau217 proves useful as a biomarker for Alzheimer's disease in low- and middle-income country such as Thailand.

Neuropsychiatric Symptom Profile in Alzheimer's Disease and Their Relationship With Functional Decline.

OBJECTIVE: Understanding the course of individual neuropsychiatric symptoms (NPS) and their relationship with function is important for planning targeted interventions for preventing and delaying functional decline. This study aims to disentangle relative contributions of individual NPS on functional decline. METHODS: Longitudinal study of 9,358 well-characterized participants with baseline diagnoses of Mild Cognitive Impairment or AD in the National Alzheimer's Coordinating Center Uniform Data Set. Function was measured using the Functional Assessment Questionnaire (FAQ). Clinician judgment of seven common behavioral symptoms were examined simultaneously: apathy-withdrawal, depressed mood, visual or auditory hallucinations, delusions, disinhibition, irritability, and agitation. RESULTS: Apathy was the most common NPS at baseline (33.7%) and throughout follow-up, endorsed by clinicians in 63.7% of visits. Apathy was the most persistent with 36.7% of participants having clinician-endorsed apathy in ≥50% of their visits. Apathy strongly correlated with faster rate of functional decline. Compared to those who never had apathy, baseline FAQ was worse in those with intermittent or persistent/always apathy (intermittent: estimated coefficient ±SE=1.228±0.210, 95% CI=[0.817, 1.639]; persistent/always: 2.354±0.244 (95% CI=[1.876, 2.832], both p <0.001). Over time, rate of functional decline was faster in those with intermittent and persistent/always apathy (intermittent: 0.454±0.091, 95% CI=[0.276, 0.632]; persistent/always: 0.635±0.102, 95% CI=[0.436, 0.835], both p <0.001). Worse agitation, delusions, and hallucinations also correlated with functional decline, but magnitudes of the estimates were smaller. CONCLUSION: Individual NPS may be sensitive targets for tracking longitudinal change in function. The study raises awareness of the need for more comprehensive assessment of functional decline in AD patients with noncognitive symptoms.

Astaxanthin Rescues Memory Impairments in Rats with Vascular Dementia by Protecting Against Neuronal Death in the Hippocampus.

Vascular dementia (VaD) is a cognitive disorder characterized by a decline in cognitive function resulting from cerebrovascular disease. The hippocampus is particularly susceptible to ischemic insults, leading to memory deficits in VaD. Astaxanthin (AST) has shown potential therapeutic effects in neurodegenerative diseases. However, the mechanisms underlying its protective effects in VaD and against hippocampal neuronal death remain unclear. In this study, We used the bilateral common carotid artery occlusion (BCCAO) method to establish a chronic cerebral hypoperfusion (CCH) rat model of VaD and administered a gastric infusion of AST at 25 mg/kg per day for 4 weeks to explore its therapeutic effects. Memory impairments were assessed using Y-maze and Morris water maze tests. We also performed biochemical analyses to evaluate levels of hippocampal neuronal death and apoptosis-related proteins, as well as the impact of astaxanthin on the PI3K/Akt/mTOR pathway and oxidative stress. Our results demonstrated that AST significantly rescued memory impairments in VaD rats. Furthermore, astaxanthin treatment protected against hippocampal neuronal death and attenuated apoptosis. We also observed that AST modulated the PI3K/Akt/mTOR pathway, suggesting its involvement in promoting neuronal survival and synaptic plasticity. Additionally, AST exhibited antioxidant properties, mitigating oxidative stress in the hippocampus. These findings provide valuable insights into the potential therapeutic effects of AST in VaD. By elucidating the mechanisms underlying the actions of AST, this study highlights the importance of protecting hippocampal neurons and suggests potential targets for intervention in VaD. There are still some unanswered questions include long-term effects and optimal dosage of the use in human. Further research is warranted to fully understand the therapeutic potential of AST and its application in the clinical treatment of VaD.