Differences between the behavioral and psychological symptoms of Alzheimer's disease and Parkinson's disease

Microneedles: A Versatile Drug Delivery Carrier for Phytobioactive Compounds as a Therapeutic Modulator for Targeting Mitochondrial Dysfunction in the Management of Neurodegenerative Diseases

Neurodegenerative disease (ND) is the fourth leading cause of death worldwide, with limited symptomatic therapies. Mitochondrial dysfunction is a major risk factor in the progression of ND, and it-increases the generation of reactive oxygen species (ROS). Overexposure to these ROS induces apoptotic changes leading to neuronal cell death. Many studies have shown the prominent effect of phytobioactive compounds in managing mitochondrial dysfunctions associated with ND, mainly due to their antioxidant properties. The drug delivery to the brain is limited due to the presence of the blood-brain barrier (BBB), but effective drug concentration needs to reach the brain for the therapeutic action. Therefore, developing safe and effective strategies to enhance drug entry in the brain is required to establish ND's treatment. The microneedle-based drug delivery system is one of the effective non-invasive techniques for drug delivery through the transdermal route. Microneedles are micronsized drug delivery needles that are self-administrable. It can penetrate through the stratum corneum skin layer without hitting pain receptors, allowing the phytobioactive compounds to be released directly into systemic circulation in a controlled manner. With all of the principles mentioned above, this review discusses microneedles as a versatile drug delivery carrier for the phytoactive compounds as a therapeutic potentiating agent for targeting mitochondrial dysfunction for the management of ND.

Effectiveness and safety of monoclonal antibodies against amyloid-beta vis-à-vis placebo in mild or moderate Alzheimer's disease

Backgrounds and objectives

Currently, no consensus has been reached on the therapeutic implications of monoclonal antibodies against amyloid-beta (Aβ) in Alzheimer's disease (AD). This study aimed to examine the effectiveness and safety of monoclonal antibodies against Aβ as a whole and also to determine the superiority of individual antibodies vis-à-vis placebo in mild or moderate AD.

Methods

Literature retrieval, article selection, and data abstraction were performed independently and in duplicate. Cognition and function were appraised by the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), Disability Assessment for Dementia (DAD), and Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB). Effect sizes are expressed as standardized mean difference (SMD) with a 95% confidence interval (CI).

Results

Twenty-nine articles involving 108 drug-specific trials and 21,383 participants were eligible for synthesis. Of the four assessment scales, only CDR-SB was significantly reduced after using monoclonal antibodies against Aβ relative to placebo (SMD: −0.12; 95% CI: −0.2 to −0.03; p = 0.008). Egger's tests indicated a low likelihood of publication bias. At individual levels, bapineuzumab was associated with a significant increase in MMSE (SMD: 0.588; 95% CI: 0.226–0.95) and DAD (SMD: 0.919; 95% CI: 0.105–1.943), and a significant decrease in CDR-SB (SMD: −0.15; 95% CI: −0.282–0.018). Bapineuzumab can increase the significant risk of serious adverse events (OR: 1.281; 95% CI: 1.075–1.525).

Conclusion

Our findings indicate that monoclonal antibodies against Aβ can effectively improve instrumental activities of daily life in mild or moderate AD. In particular, bapineuzumab can improve cognition and function, as well as activities of daily life, and meanwhile, it triggers serious adverse events.

Neuropsychiatric Symptoms Assessment: Cross-cultural Adaptation and Validation of the Portuguese Abe's BPSD Score (ABS)

OBJECTIVES

This study aims to report on the development and psychometric properties of the Portuguese-language Abe's BPSD score (ABS) to screen for neuropsychiatric symptoms (NPS).

METHODS

ISPOR and COSMIN recommendations were followed to translate and culturally adapt the ABS. A validation study was conducted to assess the psychometric properties of the newly-translated instrument. Outpatients attending a psychogeriatric consultation were included by consecutive referrals and were assessed with the ABS, the Neuropsychiatric Inventory (NPI) and NPI Caregiver Distress scale (NPI-D), and the Mini-Mental State Examination (MMSE). The ABS reliability (internal consistency, item-total correlations, inter-rater and test-retest reliability), validity (concurrent and convergent), feasibility and diagnostic accuracy were examined.

RESULTS

Overall, 107 participants were included. The ABS Cronbach alpha was 0.672, and item-total correlations ranged from -0.056 to 0.546. Strong inter-rater (ICC 0.997; 95%CI: 0.995-0.999) and test-retest reliability (ICC 0.976; 95%CI: 0.958-0.986) were found. Concurrent validity with NPI was high (r_s = 0.847, p < .001), and correlations with MMSE and NPI-D were also significant. An exploratory threshold score ≥2 is proposed to identify clinically relevant NPS.

CONCLUSIONS

Data provide satisfactory proof of ABS psychometric characteristics. Nevertheless, some items exhibited less optimal properties.

CLINICAL IMPLICATIONS

The newly-translated instrument proved to be relevant, valid and easy to use in a real geriatric clinical setting.

The congruency of neuropsychological and F18-FDG brain PET/CT diagnostics of Alzheimer's Disease (AD) in routine clinical practice: insights from a mixed neurological patient cohort

Background

Diagnostics of Alzheimer’s Disease (AD) require a multimodal approach. Neuropsychologists examine the degree and etiology of dementia syndromes and results are combined with those of cerebrospinal fluid markers and imaging data. In the diagnostic process, neuropsychologists often rely on anamnestic and clinical information, as well as cognitive tests, prior to the availability of exhaustive etiological information. The congruency of this phenomenological approach with results from FDG-PET/CT examinations remains to be explored. The latter yield highly accurate diagnostic information.

Method

A mixed sample of N = 127 hospitalized neurological patients suspected of displaying a dementia syndrome underwent extensive neuropsychological and FDG-PET/CT examinations. Neuropsychological examinations included an anamnestic and clinical interview, and the CERAD cognitive test battery. Two decisional approaches were considered: First, routine diagnostic results were obtained, i.e. the final clinical decision of the examining neuropsychologist (AD_Clinical vs. non-AD_Clinical). Secondly, a logistic regression model was implemented, relying on CERAD profiles alone. CERAD subscales that best predicted AD based on FDG-PET/CT were identified and a nominal categorization obtained (AD_Test vs. non-AD_Test). Congruency of results from both approaches with those of the FDG-PET/CT (AD_PET vs. non-AD_PET) were estimated with Cohen’s Kappa (κ) and Yule’s Y coefficient of colligation. Descriptive estimates of accuracy, sensitivity and specificity of CERAD relative to FDG-PET/CT diagnostics were derived.

Results

AD_PET patients constituted N = 33/127 (26%) of the sample. The clinical decision approach (AD_Clinical vs. non-AD_Clinical) showed substantial agreement with the FDG-PET/CT classification (κ = .69, Y = .72) involving good accuracy (84.2%), moderate sensitivity (75.8%) and excellent specificity (92.6%). In contrast, the decisional approach that relied on CERAD data alone (AD_Test vs. non-AD_Test) involved only moderate agreement with the FDG-PET/CT (κ = .54, Y = .62) with lower accuracy (74.8%), attributable to decreased sensitivity (56.3%) and comparable specificity (93.3%).

Conclusions

It is feasible to identify AD through a comprehensive neuropsychological examination in a mixed sample of neurological patients. However, within the boundaries of methods applied here, decisions based on cognitive test results alone appear limited. One may conclude that the clinical impression based on anamnestic and clinical information obtained by the neuropsychological examiner plays a crucial role in the identification of AD patients in routine clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02614-4.

Revisit the Cellular Transmission and Emerging Techniques in Understanding the Mechanisms of Proteinopathies

Alzheimer’s and Parkinson’s diseases (AD and PD) are amongst top of the prevalent neurodegenerative disease. One-third of PD patients are diagnosed with dementia, a pre-symptom of AD, but the underlying mechanism is elusive. Amyloid beta (Aβ) and α-synuclein are two of the most investigated proteins, whose pathological aggregation and spreading are crucial to the pathogenesis of AD and PD, respectively. Transcriptomic studies of the mammalian central nervous system shed light on gene expression profiles at molecular levels, regarding the complexity of neuronal morphologies and electrophysiological inputs/outputs. In the last decade, the booming of the single-cell RNA sequencing technique helped to understand gene expression patterns, alternative splicing, novel transcripts, and signal pathways in the nervous system at single-cell levels, providing insight for molecular taxonomy and mechanistic targets of the degenerative nervous system. Here, we re-visited the cell-cell transmission mechanisms of Aβ and α-synuclein in mediating disease propagation, and summarized recent single-cell transcriptome sequencing from different perspectives and discussed its understanding of neurodegenerative diseases.

Serum aberrant expression of miR-24-3p and its diagnostic value in Alzheimer's disease

Aim: This study aimed to evaluate the effect of miR-24-3p in Alzheimer's disease (AD). Materials & methods: A total of 198 participants were recruited in this study, including 104 AD patients and 94 healthy controls. Expression of miR-24-3p was detected using quantitative real-time PCR. Receiver-operating characteristic curve was used to assess the diagnostic value of miR-24-3p. In vitro AD model was established to evaluate the effect of miR-24-3p. The downstream target was detected by luciferase reporter gene assay. Results: Expression of miR-24-3p showed 1.6-fold increase in AD group compared with healthy controls, and a negative correlation of miR-24-3p with mini-mental state examination score was obtained. Receiver-operating characteristic curve showed satisfactory diagnostic accuracy. Downregulation of miR-24-3p promoted cell proliferation and inhibited cell apoptosis. KLF8 is a target gene of miR-24-3p. Conclusion: MiR-24-3p has a certain value in the diagnosis of AD and may be a potential biomarker.

The effect of electroconvulsive therapy on neuroinflammation, behavior and amyloid plaques in the 5xFAD mouse model of Alzheimer's disease

Microglial cells are affected in Alzheimer’s disease (AD) and interact with amyloid-beta (Aβ) plaques. Apart from memory loss, depression is common in patients with AD. Electroconvulsive therapy (ECT) is an anti-depressive treatment that may stimulate microglia, induce neuroinflammation and alter the levels of soluble Aβ, but the effects of ECT on microglia and Aβ aggregation in AD are not known. We investigated the short- and long-term effects of ECT on neuroinflammation and Aβ accumulation. 5xFAD mice received either electroconvulsive stimulation (ECS n = 26) or sham treatment (n = 25) for 3 weeks. Microglia and Aβ were analyzed in samples collected 24 h, 5 weeks, or 9 weeks after the last treatment. Aβ plaques and microglia were quantified using immunohistochemistry. The concentration of soluble Aβ and cytokines was quantified using ELISA and levels of Aβ aggregates were measured with Western Blot. Microglial phagocytosis of Aβ in the hippocampus was evaluated by flow cytometry in Methoxy-X04 injected mice 24 h following the last ECS treatment. Y-maze and Elevated plus maze were performed to study behavior after 5 weeks. We could not detect any significant short- or long-term effects of ECS on Aβ pathology or neuroinflammation, but ECS reduced abnormal behavior in the Elevated Plus maze.

T1-weighted MRI-driven Brain Age Estimation in Alzheimer's Disease and Parkinson's Disease

Neuroimaging-driven brain age estimation has introduced a robust (reliable and heritable) biomarker for detecting and monitoring neurodegenerative diseases. Here, we computed and compared brain age in Alzheimer's disease (AD) and Parkinson's disease (PD) patients using an advanced machine learning procedure involving T1-weighted MRI scans and gray matter (GM) and white matter (WM) models. Brain age estimation frameworks were built using 839 healthy individuals and then the brain estimated age difference (Brain-EAD: chronological age subtracted from brain estimated age) was assessed in a large sample of PD patients (n = 160) and AD patients (n = 129), respectively. The mean Brain-EADs for GM were +9.29 ± 6.43 years for AD patients versus +1.50 ± 6.03 years for PD patients. For WM, the mean Brain-EADs were +8.85 ± 6.62 years for AD patients versus +2.47 ± 5.85 years for PD patients. In addition, PD patients showed a significantly higher WM Brain-EAD than GM Brain-EAD. In a direct comparison between PD and AD patients, we observed significantly higher Brain-EAD values in AD patients for both GM and WM. A comparison of the Brain-EAD between PD and AD patients revealed that AD patients may have a significantly "older-appearing" brain than PD patients.

Caregiver identity theory and predictors of burden and depression: Findings from the REACH II study

Objective: To examine the relationship between care recipient (person with Alzheimer's disease) ability to perform daily tasks and caregivers' (CG) perceived burden and depression, guided by the caregiver identity theory. We also examine the mediating effect of CG abilities to meet their basic needs.Methods: This study utilizes the baseline data of the REACH II study. Spearman's rho (ρ) was used to test for relationships between burden, reported depression, and each ADLs and IADLs. To further explore the relationship between burden and each ADLs and IADLs, structural equation modeling was conducted using Mplus 8.0.Results: Reported CG total scores indicated increased perceived CG burden with greater number of assisted daily activities. CG depression scores were significantly predicted by reported burden scores and caregiver's ability to pay for basic needs. Importantly, 34.6% of variation in CG reported depressions scores were explained by reported burden scores. A multivariate regression model with reported burden scores, controlling for caregiver's ability to pay for basic needs, explained 36.6% of the variance in CG depression scores. Burden scores and CG ability to pay for basic needs significantly predicted depression scores. Results from the three models indicated that CG burden fully mediated the relationship between daily living skill scores and CG depression.Conclusion: Our study findings suggest the need to more closely examine the link between AD caregiving, financial instability, and mental health and bolster support for policies and programs that offer tangible supports and services to offset the costs of informal AD CG.

Voluntary running does not reduce neuroinflammation or improve non-cognitive behavior in the 5xFAD mouse model of Alzheimer's disease

Physical exercise has been suggested to reduce the risk of developing Alzheimer’s disease (AD) as well as ameliorate the progression of the disease. However, we recently published results from two large epidemiological studies showing no such beneficial effects on the development of AD. In addition, long-term, voluntary running in the 5xFAD mouse model of AD did not affect levels of soluble amyloid beta (Aβ), synaptic proteins or cognitive function. In this follow-up study, we investigate whether running could impact other pathological aspects of the disease, such as insoluble Aβ levels, the neuroinflammatory response and non-cognitive behavioral impairments. We investigated the effects of 24 weeks of voluntary wheel running in female 5xFAD mice (n = 30) starting at 2–3 months of age, before substantial extracellular plaque formation. Running mice developed hindlimb clasping earlier (p = 0.009) compared to sedentary controls. Further, running exacerbated the exploratory behavior in Elevated plus maze (p = 0.001) and anxiety in Open field (p = 0.024) tests. Additionally, microglia, cytokines and insoluble Aβ levels were not affected. Taken together, our findings suggest that voluntary wheel running is not a beneficial intervention to halt disease progression in 5xFAD mice.

Apathy rating scores and β-amyloidopathy in patients with Parkinson disease at risk for cognitive decline

OBJECTIVE

To determine whether β-amyloidopathy correlates with apathy rating scores independently of mood changes and other neurodegenerative processes in Parkinson disease (PD).

METHODS

In this cross-sectional study, patients with PD (n = 64, 48 male and 16 female, mean age 69.2 ± 6.7 years, Hoehn & Yahr stage 2.7 ± 0.5, Montreal Cognitive Assessment score 25.3 ± 3.0) underwent [¹¹C]Pittsburgh compound B β-amyloid, [¹¹C]dihydrotetrabenazine vesicular monoamine transporter type 2 (VMAT2), and [¹¹C]methyl 4 piperidinyl propionate acetylcholinesterase brain PET imaging and clinical assessments, including the Marin Apathy Evaluation Scale, Clinician Version. Patients were recruited on the basis of having at least 1 risk factor for PD dementia, but they were excluded if they had dementia.

RESULTS

Mean apathy rating score was 25.4 ± 6.4, reflecting predominantly subclinical apathy. Apathy rating scale scores correlated with amyloid binding, cognitive, depressive, and anxiety scores but not significantly with age, duration of disease, striatal VMAT2, or cholinergic binding. Multiple regression analysis model (p < 0.0001) showed significant regressor effects for global β-amyloid burden (p = 0.0038) with significant covariate effects for global cognitive z scores (p = 0.028) and for anxiety (p = 0.038) but not with depressive scores. Voxel-based analysis showed robust correlation between apathy rating scale scores and β-amyloid binding in bilateral nuclei accumbens, inferior frontal, and cingulate cortices (family-wise error rate-corrected p < 0.005).

CONCLUSION

Apathy is independently associated with β-amyloidopathy in patients with PD at risk of dementia. Regional brain findings are most robust for β-amyloidopathy in the nuclei accumbens, inferior frontal, and cingulate regions. Findings may provide an explanation for the often treatment-refractory nature of apathy in advancing PD despite optimized dopaminergic and antidepressant pharmacotherapy.

CLINICALTRIALSGOV IDENTIFIER

NCT01565473.

Donepezil's Effects on Brain Functions of Patients With Alzheimer Disease: A Regional Homogeneity Study Based on Resting-State Functional Magnetic Resonance Imaging

PURPOSE

Donepezil is known to increase cholinergic synaptic transmission in Alzheimer disease (AD), although how it affects cortical brain activity and how it consequently affects brain functions need further clarification. To investigate the therapeutic mechanism of donepezil underlying its effect on brain function, regional homogeneity (ReHo) technology was used in this study.

PATIENTS AND METHODS

This study included 11 mild-to-moderate AD patients who completed 24 weeks of donepezil treatment and 11 matched healthy controls. All participants finished neuropsychological assessment and resting-state functional magnetic resonance imaging scanning to compare whole-brain ReHo before and after donepezil treatment.

RESULTS

Significantly decreased Alzheimer's Disease Assessment Scale-Cognitive Subscale scores (P = 0.010) and increased Mini-Mental State Examination scores (P = 0.043) were observed in the AD patients. In addition, in the right gyrus rectus (P = 0.021), right precentral gyrus (P = 0.026), and left superior temporal gyrus (P = 0.043) of the AD patients, decreased ReHo was exhibited.

CONCLUSION

Donepezil-mediated improvement of cognitive function in AD patients is linked to spontaneous brain activities of the right gyrus rectus, right precentral gyrus, and left superior temporal gyrus, which could be used as potential biomarkers for monitoring the therapeutic effect of donepezil.

Mitochondrial biogenesis mediated by melatonin in an APPswe/PS1dE9 transgenic mice model

Alzheimer’s disease (AD) is a chronic progressive neurodegenerative disease, but the pathogenesis is unclear. Damaged mitochondrial biogenesis has been observed in AD. Increasing evidence suggests that mitochondrial biogenesis is involved in the pathogenesis of AD, but the exact mechanism is unclear. In this study, we used the amyloid precursor protein Swedish mutations K594N/M595L (APPswe)/presenilin 1 with the exon-9 deletion (PS1dE9) transgenic mouse model of AD, which was successfully established by the expression of amyloid β precursor protein and presenilin 1 (PS1). Then, we compared APPswe/PS1dE9 transgenic mice with and without melatonin (MT) in drinking water for 4 months (estimated 0.5 mg/day) and control C57BL/6J mice without MT for expression of mitochondrial biogenesis factors (mitochondrial transcription factor A, nuclear respiratory factor 1 and 2, peroxisome proliferator-activated receptor γ coactivator 1-α), mitochondrial structure, mitochondrial DNA to nuclear DNA ratio, behavioral changes, and amyloid β (Aβ) deposition and soluble Aβ levels in the cerebral cortex and hippocampus. Compared with controls, APPswe/PS1dE9 mice with long-term MT intake showed increased levels of mitochondrial biogenesis factors, alleviated mitochondrial impairment, enhanced mitochondrial DNA copy number, improved spatial learning and memory deficits, and reduced Aβ deposition and soluble Aβ levels. Defective mitochondrial biogenesis may contribute toward the damaged mitochondrial structure and function in AD. MT may alleviate AD by promoting mitochondrial biogenesis.

PET/MR Imaging: New Frontier in Alzheimer's Disease and Other Dementias

Alzheimer's disease (AD) is the most common form of dementia; a progressive neurodegenerative disease that currently lacks an effective treatment option. Early and accurate diagnosis, in addition to quick elimination of differential diagnosis, allows us to provide timely treatments that delay the progression of AD. Imaging plays an important role for the early diagnosis of AD. The newly emerging PET/MR imaging strategies integrate the advantages of PET and MR to diagnose and monitor AD. This review introduces the development of PET/MR imaging systems, technical considerations of PET/MR imaging, special considerations of PET/MR in AD, and the system's potential clinical applications and future perspectives in AD.