Neuropsychiatric Disturbances in Alzheimer's Disease: What Have We Learned from Neuropathological Studies?

Monoamine alterations in Alzheimer's disease and their implications in comorbid neuropsychiatric symptoms

Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by relentless cognitive decline and the emergence of profoundly disruptive neuropsychiatric symptoms. As the disease progresses, it unveils a formidable array of neuropsychiatric manifestations, including debilitating depression, anxiety, agitation, and distressing episodes of psychosis. The intricate web of the monoaminergic system, governed by serotonin, dopamine, and norepinephrine, significantly influences our mood, cognition, and behavior. Emerging evidence suggests that dysregulation and degeneration of this system occur early in AD, leading to notable alterations in these critical neurotransmitters' levels, metabolism, and receptor function. However, how the degeneration of monoaminergic neurons and subsequent compensatory changes contribute to the presentation of neuropsychiatric symptoms observed in Alzheimer's disease remains elusive. This review synthesizes current findings on monoamine alterations in AD and explores how these changes contribute to the neuropsychiatric symptomatology of the disease. By elucidating the biological underpinnings of AD-related psychiatric symptoms, we aim to underscore the complexity and inform innovative approaches for treating neuropsychiatric symptoms in AD.

The Difference in Cognitive Profiles Between Patients With Alzheimer Dementia With and Without Psychosis: A Rapid Review

BACKGROUND

Psychosis in Alzheimer disease (AD) is a major burden for patients and their family. Identifying the characteristics of delusions and hallucinations in the AD population is key to understanding the interconnection between the psychiatric and cognitive symptoms in neurocognitive disorders. The aim of this study is to compare the cognitive profiles of AD patients with and without psychosis.

METHODS

We conducted a rapid review to explore the relationship between psychotic symptoms and cognitive performances in patients with AD. We used MEDLINE, Embase, and PsychINFO literature databases between January 2015 and January 2023. This rapid review was guided by the Cochrane Rapid Reviews Methods Group.

RESULTS

We identified 2909 records from the initial searches. After reviewing the titles, abstracts, and full texts, we selected 8 cross-sectional and 5 cohort studies for the qualitative analysis. Among them, 6 studies were included in the final quantitative analysis. Most studies suggested a correlation between general cognitive decline and the risk of presenting psychotic symptoms. Three studies found an association between hallucinations and deficits in the visuocognitive domains (visuospatial, visuoperceptual, and visuoconstructive skills). Two studies found a relationship between psychotic symptoms and executive dysfunction. Two studies also found a correlation between psychotic symptoms and language. Our results are in line with previous data in the literature, especially regarding the outcome of psychosis on executive function and visuocognitive abilities.

CONCLUSIONS

There appears to be an association between cognitive deficits and psychotic symptoms in AD, but the direction of causality is still unclear, and further studies using longitudinal designs would give more insight into the pathophysiological process of psychosis in AD.

The association of depression and apathy with Alzheimer's disease biomarkers in a cross-cultural sample

Cross-cultural differences in the association between neuropsychiatric symptoms and Alzheimer's disease (AD) biomarkers are not well understood. This study aimed to (1) compare depressive symptoms and frequency of reported apathy across diagnostic groups of participants with normal cognition (CN), mild cognitive impairment (MCI), and dementia, as well as ethnic groups of Hispanic Americans (HA) and European Americans (EA); (2) evaluate the relationship between depression and apathy with Aβ deposition and brain atrophy. Statistical analyses included ANCOVAs, chi-squared, nonparametric tests, correlations, and logistic regressions. Higher scores on the Geriatric Depression Scale (GDS-15) were reported in the MCI and dementia cohorts, while older age corresponded with lower GDS-15 scores. The frequency of apathy differed across diagnoses within each ethnicity, but not when comparing ethnic groups. Reduced volume in the rostral anterior cingulate cortex (ACC) significantly correlated with and predicted apathy for the total sample after applying false discovery rate corrections (FDR), controlling for covariates. The EA group separately demonstrated a significant negative relationship between apathy and superior frontal volume, while for HA, there was a relationship between rostral ACC volume and apathy. Apathy corresponded with higher Aβ levels for the total sample and for the CN and HA groups.

Hypoglycemic TCM formulas (Huangqi-Gegen drug pair) have the potential as an Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a neurological disorder. There is a considerable unmet medical need among those suffering from it.

HYPOTHESIS AND PURPOSE

Given the link between type-2 diabetes mellitus (T2DM) and AD, hypoglycemic traditional Chinese medicine formulas (TCMFs) may be a treatment for AD. We investigated the possibility of identifying anti-AD medicines in hypoglycemic TCMFs and presented another option for the screening of AD medications.

STUDY DESIGN AND METHODS

Paralysis of the transgenic Caenorhabditis elegans (C. elegans) strain CL4176 (caused by amyloid beta (Aβ)1-42 aggregates) was used to evaluate the anti-AD effect. The toxicity and neurodegeneration induced by neuronal expression of Aβ in the transgenic C. elegans strain CL2355 were determined using a 5-hydroxytryptamine (5-HT) assay. The transgenic Aβ-expressing strain CL 2006 and transgenic tau-expressing strain BR5270 were used to explore the effect of TCMFs on protein expression in C. elegans using ELISAs. Then, network pharmacology was used to determine the mechanism of action. The Traditional Chinese Medicine Inheritance Support System platform was used to investigate prescription patterns, core drugs, and optimum combinations of hypoglycemic TCMFs for AD.

RESULTS

Sixteen hypoglycemic TCMFs prolonged the PT50 (half paralysis time) of the CL4176 strain of C. elegans, reduced the percentage of worms paralyzed. The results of network pharmacology showed that prostaglandin-endoperoxide synthase 2 (PTGS2) and acetylcholine esterase (AChE) are main targets of hypoglycemic TCMFs. Enriched pathway analysis showed that the cholinergic receptor-related pathway was the core pathway of hypoglycemic TCMFs. According to the "four qi and five flavors" system of TCM theory, the main pharmacological qualities were "cold" and "sweet." Through the analysis by TCMISS, we found that Huangqi-Gegen drug pair as the significant Chinese herbs of hypoglycemic TCMFs. The Huangqi-Gegen pairing had the most robust therapeutic effect when delivered at a 2:1 (v/v) ratio. It reduced the paralysis caused by 5-HT, decreased protein expression of AChE and PTGS2, and reduced Aβ deposition in the brain of the CL2006 strain of C. elegans.

CONCLUSIONS

Huangqi-Gegen is a promising treatment of AD, and its mechanism may be induced by suppressing the protein production of AChE and PTGS2, reducing 5-HT intake, and then decreasing Aβ deposition.

Advanced Immunolabeling Method for Optical Volumetric Imaging Reveals Dystrophic Neurites of Dopaminergic Neurons in Alzheimer's Disease Mouse Brain

Optical brain clearing combined with immunolabeling is valuable for analyzing molecular tissue structures, including complex synaptic connectivity. However, the presence of aberrant lipid deposition due to aging and brain disorders poses a challenge for achieving antibody penetration throughout the entire brain volume. Herein, we present an efficient brain-wide immunolabeling method, the immuno-active clearing technique (iACT). The treatment of brain tissues with a zwitterionic detergent, specifically SB3-12, significantly enhanced tissue permeability by effectively mitigating lipid barriers. Notably, Quadrol treatment further refines the methodology by effectively eliminating residual detergents from cleared brain tissues, subsequently amplifying volumetric fluorescence signals. Employing iACT, we uncover disrupted axonal projections within the mesolimbic dopaminergic (DA) circuits in 5xFAD mice. Subsequent characterization of DA neural circuits in 5xFAD mice revealed proximal axonal swelling and misrouting of distal axonal compartments in proximity to amyloid-beta plaques. Importantly, these structural anomalies in DA axons correlate with a marked reduction in DA release within the nucleus accumbens. Collectively, our findings highlight the efficacy of optical volumetric imaging with iACT in resolving intricate structural alterations in deep brain neural circuits. Furthermore, we unveil the compromised integrity of DA pathways, contributing to the underlying neuropathology of Alzheimer's disease. The iACT technique thus holds significant promise as a valuable asset for advancing our understanding of complex neurodegenerative disorders and may pave the way for targeted therapeutic interventions.

Distinguishing features of depression in dementia from primary psychiatric disease

Depression is a common and devastating neuropsychiatric symptom in the elderly and in patients with dementia. In particular, nearly 80% of patients with Alzheimer's Disease dementia experience depression during disease development and progression. However, it is unknown whether the depression in patients with dementia shares the same molecular mechanisms as depression presenting as primary psychiatric disease or occurs and persists through alternative mechanisms. In this review, we discuss how the clinical presentation and treatment differ between depression in dementia and as a primary psychiatric disease, with a focus on major depressive disorder. Then, we hypothesize several molecular mechanisms that may be unique to depression in dementia such as neuropathological changes, inflammation, and vascular events. Finally, we discuss existing issues and future directions for investigation and treatment of depression in dementia.

Neuropsychiatric features in a multi-ethnic population with Alzheimer disease and mild cognitive impairment

BACKGROUND

Alzheimer disease (AD) is more prevalent in African American (AA) and Hispanic White (HIW) compared to Non-Hispanic White (NHW) individuals. Similarly, neuropsychiatric symptoms (NPS) vary by population in AD. This is likely the result of both sociocultural and genetic ancestral differences. However, the impact of these NPS on AD in different groups is not well understood.

METHODS

Self-declared AA, HIW, and NHW individuals were ascertained as part of ongoing AD genetics studies. Participants who scored higher than 0.5 on the Clinical Dementia Rating (CDR) Scale (CDR) were included. Group similarities and differences on Neuropsychiatric Inventory Questionnaire (NPI-Q) outcomes (NPI-Q total score, NPI-Q items) were evaluated using univariate ANOVAs and post hoc comparisons after controlling for sex and CDR stage.

RESULTS

Our sample consisted of 498 participants (26% AA; 30% HIW; 44% NHW). Overall, NPI-Q total scores differed significantly between our groups, with HIW having the highest NPI-Q total scores, and by AD stage as measured by CDR. We found no significant difference in NPI-Q total score by sex. There were six NPI-Q items with comparable prevalence in all groups and six items that significantly differed between the groups (Anxiety, Apathy, Depression, Disinhibition, Elation, and Irritability). Further, within the HIW group, differences were found between Puerto Rican and Cuban American Hispanics across several NPI-Q items. Finally, Six NPI-Q items were more prevalent in the later stages of AD including Agitation, Appetite, Hallucinations, Irritability, Motor Disturbance, and Nighttime Behavior.

CONCLUSIONS

We identified differences in NPS among HIW, AA, and NHW individuals. Most striking was the high burden of NPS in HIW, particularly for mood and anxiety symptoms. We suggest that NPS differences may represent the impact of sociocultural influences on symptom presentation as well as potential genetic factors rooted in ancestral background. Given the complex relationship between AD and NPS it is crucial to discern the presence of NPS to ensure appropriate interventions.

A 2023 update on the advancements in the treatment of agitation in Alzheimer's disease

INTRODUCTION

Neuropsychiatric symptoms (NPS) in Alzheimer's Disease (AD) are associated with negative outcomes for patients and their care partners. Agitation is one of the most common and distressing NPS, yet we lack safe and effective treatment options. While nonpharmacologic interventions are considered first line treatment, these may not be effective or appropriate for every patient. Our current approaches to the pharmacologic treatment of agitation in AD consist of the off-label use of antipsychotics, sedative/hypnotics, anxiolytics, mood-stabilizing anticonvulsants, acetylcholinesterase inhibitors, NMDA receptor antagonists, and antidepressants. Despite their prevalent use, they have questionable efficacy and significant safety concerns.

AREAS COVERED

Advances in the understanding of neurobiological mechanisms of agitation have fueled recent clinical trials. This article is an update to our 2017 review. A comprehensive search of ClinicalTrials.gov was completed from January 2017 to June 2022 using the search terms "Alzheimer's Disease" and "Agitation". A subsequent scoping review was completed in PubMed and Google Scholar. Several agents were identified for promise in treating agitation, including: brexpiprazole, cannabinoids, dexmedetomidine, dextromethorphan, escitalopram, masupirdine, and prazosin.

EXPERT OPINION

Clinical trials remain underway utilizing both novel and repurposed agents to address symptoms of agitation in AD. With increasing understanding of the neurobiological mechanisms that fuel the development of agitation in AD, the use of enhanced trial design and conduct, advanced statistical approaches, and accelerated pathways for regulatory approval, we are advancing closer to having safe and efficacious treatment options for agitation in AD.

Long-Term Supplementation of Syzygium cumini (L.) Skeels Concentrate Alleviates Age-Related Cognitive Deficit and Oxidative Damage: A Comparative Study of Young vs. Old Mice

The Syzygium cumini (L.) Skeels is reported to have medicinal properties, but its benefits on age-related neurological changes have not been previously explored. In the current study, after phytochemical analysis of the pulp of Syzygium cumini (L.) Skeels fruit (Sy. cmi), young BALB/c mice have been supplemented with its 5, 15, and 30% dilution for 16 months, followed by behavioral experimentation and biochemical evaluation of isolated brains. The Sy. cmi has been found enriched with phenols/flavonoids while the occurrence of nine phytocompounds has been identified through GC-MS analysis. Further, Sy. cmi supplementation has caused significant (p < 0.05) protection from anxiety-like behavior in aged mice, and they have explored open, illuminated, and exposed areas of open field, light/dark, and an elevated plus maze, respectively. Furthermore, these animals have shown improved cognitive abilities as their percent (%) spontaneous alteration and novelty preference are significantly greater in T-maze and Y-maze and familiarity/novelty recognition tests. Further, Sy. cmi-supplemented mice remember the aversive stimuli zone and escape box location in passive avoidance and Barnes maze tests, and their brains have low levels of malondialdehyde and acetylcholinesterase with elevated antioxidant enzymes. The outcomes have provided scientific insight into the beneficial effects of Sy. cmi on age-associated amnesia that might be attributed to antioxidant and anticholinergic effects exerted by phytocompounds (caryophyllene, humulene, β-Farnesene, and phytol) owned by Syzygium cumini.

Role of angiotensin receptor blockers in the context of Alzheimer's disease

As the world's population ages, the prevalence of age-related neurological disorders such as Alzheimer's disease (AD) is increasing. There is currently no treatment for Alzheimer's disease, and the few approved medications have a low success rate in lowering symptoms. As a result, several attempts are underway worldwide to identify new targets for the therapy of Alzheimer's disease. In preclinical studies of Alzheimer's disease, it was recently found that inhibition of angiotensin-converting enzyme (ACE) and blocking of the angiotensin II receptors reduce symptoms of neurodegeneration, Aβ plaque development, and tau hyperphosphorylation. Angiotensin II type I (AT1) blockers, such as telmisartan, candesartan, valsartan, and others, have a wide safety margin and are commonly used to treat hypertension. Renal and cardiovascular failures are reduced due to their vascular protective actions. Inhibition of AT1 receptors in the brain has a neuroprotective impact in humans, reducing the risk of stroke, increasing cognition, and slowing the progression of Alzheimer's disease. The review focuses on the mechanisms via which AT1 blockers may act beneficially in Alzheimer's disease. Although their effect is evident in preclinical studies, clinical trials, on the other hand, are in short supply to validate the strategy. More dose-response experiments with possible AT1 blockers and brain-targeted administration will be needed in the future.

Common Neuropsychiatric S ymptoms in Alzheimer's Disease, Mild Cognitive Impairment, and Subjective Memory Complaints: A Unified Framework

The Alzheimer's disease (AD) continuum is a unique spectrum of cognitive impairment that typically involves the stages of subjective memory complaints (SMC), mild cognitive impairment (MCI), and AD dementia. Neuropsychiatric symptoms (NPS), such as apathy, anxiety, stress, and depression, are highly common throughout the AD continuum. However, there is a dearth of research on how these NPS vary across the AD continuum, especially SMC. There is also disagreement on the effects of specific NPS on each stage of the AD continuum due to their collinearity with other NPS, cognitive decline, and environmental factors (e.g., stress). In this article, we conduct a novel perspective review of the scientific literature to understand the presence of NPS across the AD continuum. Specifically, we review the effects of apathy, depression, anxiety, and stress in AD, MCI, and SMC. We then build on this knowledge by proposing two theories of NPS' occurrence across the AD continuum. Consequently, we highlight the current landscape, limitations (e.g., differing operationalization), and contentions surrounding the NPS literature. We also outline theories that could clear up contention and inspire future NPS research.

Alzheimer's Disease: Challenges and a Therapeutic Opportunity to Treat It with a Neurotrophic Compound

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with an insidious onset and multifactorial nature. A deficit in neurogenesis and synaptic plasticity are considered the early pathological features associated with neurofibrillary tau and amyloid β pathologies and neuroinflammation. The imbalance of neurotrophic factors with an increase in FGF-2 level and a decrease in brain derived neurotrophic factor (BDNF) and neurotrophin 4 (NT-4) in the hippocampus, frontal cortex and parietal cortex and disruption of the brain micro-environment are other characteristics of AD. Neurotrophic factors are crucial in neuronal differentiation, maturation, and survival. Several attempts to use neurotrophic factors to treat AD were made, but these trials were halted due to their blood-brain barrier (BBB) impermeability, short-half-life, and severe side effects. In the present review we mainly focus on the major etiopathology features of AD and the use of a small neurotrophic and neurogenic peptide mimetic compound; P021 that was discovered in our laboratory and was found to overcome the difficulties faced in the administration of the whole neurotrophic factor proteins. We describe pre-clinical studies on P021 and its potential as a therapeutic drug for AD and related neurodegenerative disorders. Our study is limited because it focuses only on P021 and the relevant literature; a more thorough investigation is required to review studies on various therapeutic approaches and potential drugs that are emerging in the AD field.

Association of locus coeruleus integrity with Braak stage and neuropsychiatric symptom severity in Alzheimer's disease

The clinical and pathophysiological correlates of locus coeruleus (LC) degeneration in Alzheimer's disease (AD) could be clarified using a method to index LC integrity in vivo, neuromelanin-sensitive MRI (NM-MRI). We examined whether integrity of the LC-norepinephrine system, assessed with NM-MRI, is associated with stage of AD and with neuropsychiatric symptoms (NPS), independent of cortical pathophysiology (amyloid-β and tau burden). Cognitively normal older adults (n = 118), and individuals with mild cognitive impairment (MCI, n = 44), and AD (n = 28) underwent MR imaging and tau and amyloid-β positron emission tomography (with [¹⁸F]MK6240 and [¹⁸F]AZD4694, respectively). Integrity of the LC-norepinephrine system was assessed based on contrast-to-noise ratio of the LC on NM-MRI images. Braak stage of AD was derived from regional binding of [¹⁸F]MK6240. NPS were assessed with the Mild Behavioral Impairment Checklist (MBI-C). LC signal contrast was decreased in tau-positive participants (t₁₈₆ = -4.00, p = 0.0001) and negatively correlated to Braak stage (Spearman ρ = -0.31, p = 0.00006). In tau-positive participants (n = 51), higher LC signal predicted NPS severity (ρ = 0.35, p = 0.019) independently of tau burden, amyloid-β burden, and cortical gray matter volume. This relationship appeared to be driven by the impulse dyscontrol domain of NPS, which was highly correlated to LC signal (ρ = 0.44, p = 0.0027). NM-MRI reveals loss of LC integrity that correlates to severity of AD. However, LC preservation in AD may also have negative consequences by conferring risk for impulse control symptoms. NM-MRI shows promise as a practical biomarker that could have utility in predicting the risk of NPS or guiding their treatment in AD.

Mapping the sequence specificity of heterotypic amyloid interactions enables the identification of aggregation modifiers

Heterotypic amyloid interactions between related protein sequences have been observed in functional and disease amyloids. While sequence homology seems to favour heterotypic amyloid interactions, we have no systematic understanding of the structural rules determining such interactions nor whether they inhibit or facilitate amyloid assembly. Using structure-based thermodynamic calculations and extensive experimental validation, we performed a comprehensive exploration of the defining role of sequence promiscuity in amyloid interactions. Using tau as a model system we demonstrate that proteins with local sequence homology to tau amyloid nucleating regions can modify fibril nucleation, morphology, assembly and spreading of aggregates in cultured cells. Depending on the type of mutation such interactions inhibit or promote aggregation in a manner that can be predicted from structure. We find that these heterotypic amyloid interactions can result in the subcellular mis-localisation of these proteins. Moreover, equilibrium studies indicate that the critical concentration of aggregation is altered by heterotypic interactions. Our findings suggest a structural mechanism by which the proteomic background can modulate the aggregation propensity of amyloidogenic proteins and we discuss how such sequence-specific proteostatic perturbations could contribute to the selective cellular susceptibility of amyloid disease progression.

In this work, Louros et al. uncover a rule book for interactions of amyloids with other proteins. This grammar was shown to promote cellular spreading of tau aggregates in cells, but can also be harvested to develop structure-based aggregation blockers.

Gender Differences in Demographic and Pharmacological Factors in Patients Diagnosed with Late-Onset of Alzheimer’s Disease

Background: Whether gender differences exist in late-onset of Alzheimer’s disease (LOAD) treated with cholinesterase inhibitors (ChEIs) is not fully understood. This study investigated demographic and pharmacological characteristics in LOAD patients to determine gender differences in LOAD patients treated with ChEIs alone and ChEIs with other medications. Methods: This 5-year retrospective data analysis included 9290 LOAD AD patients with 2949 men patients and 6341 women. Potential predictors of demographic and pharmacological characteristics associated gender differences in patients treated with and without ChEIs therapy were determined using univariate analysis, while multivariable models adjusted for demographic and pharmacological variables. Results: In the adjusted analysis, men patients with LOAD that presented with a history of alcohol use (ETOH) (OR = 1.339, 95% CI, 1.072–1.672, p = 0.010), treated with second generation antipsychotics (SGAs) (OR = 1.271, 95% CI, 1.003–1.610, p = 0.047), citalopram (OR = 5.103, 95% CI, 3.423–7.607, p < 0.001), memantine (OR = 4.409, 95% CI, 3.704–5.249, p < 0.001), and buspirone (OR = 2.166, 95% CI, 1.437–3.264, p < 0.001) were more likely to receive ChEIs therapy, whereas older men were less likely to be treated with ChEIs therapy. Women who were African Americans (OR = 1.387, 95% CI, 1.168–1.647, p < 0.001), that received memantine (OR = 3.412, 95% CI, 3.034–3.837, p < 0.001), selective serotonin reuptake inhibitor (SSRIs) (OR = 1.143, 95% CI, 1.016–1.287, p = 0.026), and a history of ETOH (OR = 2.109, 95% CI, 1.724–2.580, p < 0.001) were more likely to receive ChEIs therapy, whereas older women were less likely to receive ChEIs therapy. Conclusion: In both men and women patients, those with increasing age were less likely to be treated with ChEI therapy, while patients treated with memantine were also likely to receive ChEI therapy. Our findings highlight the importance for clinicians to optimize ChEI in LOAD to improve treatment effectiveness and eliminate gender differences in ChEI therapy.

Adenosine Receptors in Neuropsychiatric Disorders: Fine Regulators of Neurotransmission and Potential Therapeutic Targets

Adenosine exerts an important role in the modulation of central nervous system (CNS) activity. Through the interaction with four G-protein coupled receptor (GPCR) subtypes, adenosine subtly regulates neurotransmission, interfering with the dopaminergic, glutamatergic, noradrenergic, serotoninergic, and endocannabinoid systems. The inhibitory and facilitating actions of adenosine on neurotransmission are mainly mediated by A₁ and A_2A adenosine receptors (ARs), respectively. Given their role in the CNS, ARs are promising therapeutic targets for neuropsychiatric disorders where altered neurotransmission represents the most likely etiological hypothesis. Activating or blocking ARs with specific pharmacological agents could therefore restore the balance of altered neurotransmitter systems, providing the rationale for the potential treatment of these highly debilitating conditions. In this review, we summarize and discuss the most relevant studies concerning AR modulation in psychotic and mood disorders such as schizophrenia, bipolar disorders, depression, and anxiety, as well as neurodevelopment disorders such as autism spectrum disorder (ASD), fragile X syndrome (FXS), attention-deficit hyperactivity disorder (ADHD), and neuropsychiatric aspects of neurodegenerative disorders.

Cerebral Volumetric Correlates of Apathy in Alzheimer's Disease and Cognitively Normal Older Adults: Meta-Analysis, Label-Based Review, and Study of an Independent Cohort

BACKGROUND

Affecting nearly half of the patients with Alzheimer's disease (AD), apathy is associated with higher morbidity and reduced quality of life. Basal ganglia and cortical atrophy have been implicated in apathy. However, the findings have varied across studies and left unclear whether subdomains of apathy may involve distinct neuroanatomical correlates.

OBJECTIVE

To identify neuroanatomical correlates of AD-associated apathy.

METHODS

We performed a meta-analysis and label-based review of the literature. Further, following published routines of voxel-based morphometry, we aimed to confirm the findings in an independent cohort of 19 patients with AD/mild cognitive impairment and 25 healthy controls assessed with the Apathy Evaluation Scale.

RESULTS

Meta-analysis of 167 AD and 56 healthy controls showed convergence toward smaller basal ganglia gray matter volume (GMV) in apathy. Label-based review showed anterior cingulate, putamen, insula, inferior frontal gyrus (IFG) and middle temporal gyrus (MTG) atrophy in AD apathy. In the independent cohort, with small-volume-correction, right putamen and MTG showed GMVs in negative correlation with Apathy Evaluation Scale total, behavioral, and emotional scores, and right IFG with emotional score (p < 0.05 family-wise error (FWE)-corrected), controlling for age, education, intracranial volume, and depression. With the Mini-Mental State Examination scores included as an additional covariate, the correlation of right putamen GMV with behavioral and emotional score, right MTG GMV with total and emotional score, and right IFG GMV with emotional score were significant.

CONCLUSION

The findings implicate putamen, MTG and IFG atrophy in AD associated apathy, potentially independent of cognitive impairment and depression, and suggest potentially distinct volumetric correlates of apathy.

Neuroanatomical associations of depression, anxiety and apathy neuropsychiatric symptoms in patients with Alzheimer's disease

Depression, anxiety and apathy are 'common neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). We aimed to find regional gray matter (GM) volume difference of these symptoms, in AD patients compared to AD control, and investigate possible associations of GM atrophy with cognitive covariant. Study subjects were retrieved from the Alzheimer's Disease Neuroimaging Initiative database. Thirty-five participants are AD control, 27 AD patients with anxiety, 19 with depression and 24 with apathy, ages ≥ 55.1 years. Recruited subjects had an assessment of their clinical and structural MRI data. GM differences and clinical data were analyzed using voxel-based morphometry and ANOVA with Scheffe post hoc test, respectively. We found significant GM volumes differences in the left insula, left parahippocampal, posterior cingulate and the bilateral putamen in the anxiety group. The results also revealed that the right parahippocampal, Brodmann area 38 and the middle frontal gyrus were significant in patients with depression. Significant results were with a p < 0.05, corrected with AlphaSim program for multiple comparisons. The left insula had a strong negative association with Clinical Dementia Rate Sum of Boxes and Alzheimer's Disease Assessment Scale-cognitive subscale-13 items in anxiety and apathy groups. The difference in GM density in the left insula and hippocampus plays a crucial role in depression, anxiety and apathy NPS and outline precise approaches to test these symptoms.

Calpain-Mediated Alterations in Astrocytes Before and During Amyloid Chaos in Alzheimer's Disease

One of the changes found in the brain in Alzheimer's disease (AD) is increased calpain, derived from calcium dysregulation, oxidative stress, and/or neuroinflammation, which are all assumed to be basic pillars in neurodegenerative diseases. The role of calpain in synaptic plasticity, neuronal death, and AD has been discussed in some reviews. However, astrocytic calpain changes sometimes appear to be secondary and consequent to neuronal damage in AD. Herein, we explore the possibility of calpain-mediated astroglial reactivity in AD, both preceding and during the amyloid phase. We discuss the types of brain calpains but focus the review on calpains 1 and 2 and some important targets in astrocytes. We address the signaling involved in controlling calpain expression, mainly involving p38/mitogen-activated protein kinase and calcineurin, as well as how calpain regulates the expression of proteins involved in astroglial reactivity through calcineurin and cyclin-dependent kinase 5. Throughout the text, we have tried to provide evidence of the connection between the alterations caused by calpain and the metabolic changes associated with AD. In addition, we discuss the possibility that calpain mediates amyloid-β clearance in astrocytes, as opposed to amyloid-β accumulation in neurons.

Subacute silica nanoparticle exposure induced oxidative stress and inflammation in rat hippocampus combined with disruption of cholinergic system and behavioral functions

Increasing environmental exposure to silica nanoparticles (SiNPs) and limited neurotoxicity studies pose a challenge for safety evaluation and management of these materials. This study aimed to explore the adverse effects and underlying mechanisms of subacute exposure to SiNPs by the intraperitoneal route on hippocampus function in rats. Data showed that SiNPs induced a significant increase in oxidative/nitrosative stress markers including reactive oxygen species (ROS), malondialdehyde (MDA), protein oxidation (PCO) and nitrite (NO) production accompanied by reduced antioxidant enzyme activity (catalase, superoxide dismutase, and glutathione peroxidase) and decreased glutathione (GSH). Phenotypically, SiNPs exhibited spatial learning and memory impairment in the Morris water maze (MWM) test, a decrease of the discrimination index in the novel object recognition test (NORT) and higher anxiety-like behavior. SiNPs affected the cholinergic system as reflected by reduced acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity. In addition, SiNPs significantly increased mRNA expression level of genes related to inflammation (TNF-α, IL-1β, IL-6, and COX-2) and decreased mRNA expression level of genes related to cholinergic system including choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), AChE, muscarinic acetylcholine receptor M1 (m1AChR) and nicotinic acetylcholine receptors (nAChR). Histopathological results further showed an alteration in the hippocampus of treated animals associated with marked vacuolation in different hippocampus areas. These findings provide new insights into the molecular mechanism of SiNPs-induced hippocampal alterations leading to impairment of cognitive and behavioral functions, and implicating oxidative stress and inflammation in the hippocampus, as well as disruption of cholinergic system.

5-HT7 receptors in Alzheimer's disease

Even though the involvement of serotonin (5-hydroxytryptamine; 5-HT) and its receptors in Alzheimer's disease (AD) is widely accepted, data on the expression and the role of 5-HT₇ receptors in AD is relatively limited. Therefore, the objective of the present work was to study the expression of serotonergic 5-HT₇ receptors in postmortem samples of AD brains and correlate it with neurotransmitter levels, cognition and behavior. The study population consisted of clinically well-characterized and neuropathologically confirmed AD patients (n = 42) and age-matched control subjects (n = 18). Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and high-performance liquid chromatography were performed on Brodmann area (BA) 7, BA10, BA22, BA24, hippocampus, amygdala, thalamus and cerebellum to measure mRNA levels of 5-HT₇ receptors (HTR7), as well as the concentrations of various monoamine neurotransmitters and their metabolites. Decreased levels of HTR7 mRNA were observed in BA10. A significant association was observed between HTR7 levels in BA10 and BEHAVE-AD cluster B (hallucinations) (rs(28) = 0.444, P < 0.05). In addition, a negative correlation was observed between HTR7 levels in BA10 and both MHPG concentrations in this brain region (rs(45) = -0.311; P < 0.05), and DOPAC levels in the amygdala (rs(42) = -0.311; P < 0.05). Quite surprisingly, no association was found between HTR7 levels and cognitive status. Altogether, this study supports the notion of the involvement of 5-HT₇ receptors in psychotic symptoms in AD, suggesting the interest of testing antagonist acting at this receptor to specifically treat psychotic symptoms in this illness.

Affective Neuropsychiatric Symptoms as Early Signs of Dementia Risk in Older Adults

BACKGROUND

Affective neuropsychiatric symptoms (aNPS: depression, anxiety, apathy, irritability) have been linked to increased dementia risk. However, less is known whether this association is independent of Alzheimer's disease (AD) pathophysiology.

OBJECTIVE

To investigate the contribution of early aNPS to dementia risk in cognitively normal (CN) older adults and mild cognitive impairment (MCI) patients, with and without AD biomarker abnormality.

METHODS

Participants included 763 community-dwelling, stroke-free older adults identified as CN and 617 with MCI at baseline, drawn from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Baseline assessments included a neuropsychological battery, the Neuropsychiatric Inventory (NPI), and apolipoprotein E ɛ4 (ApoE4) genotyping. A participant subset completed cerebrospinal fluid (CSF) AD biomarker assessment. Time to progression to dementia was measured based on months at follow-up when an individual was diagnosed with dementia, over the follow-up period of 48 months.

RESULTS

Latent class analysis identified 3 subgroups of older adults in CN and MCI, indicated by the baseline profiles of neuropsychiatric symptoms (NPS). Subgroups with higher aNPS were at increased risk of progression to dementia in both CN (HR = 3.65, 95% CI [1.80, 7.40]) and MCI (HR = 1.52, 95% CI [1.16, 2.00]; HR = 1.86 [1.05, 3.30]) groups, adjusting for age, sex, global cognition, and ApoE4, compared with their counterparts with minimal NPS. There was no difference between higher aNPS and minimal NPS subgroups in their CSF AD biomarker profiles.

CONCLUSION

Findings suggest that aNPS may represent a neurobiological vulnerability that uniquely contribute to the dementia risk, independent of AD biomarker profiles.

Chronic stress induces NPD-like behavior in APPPS1 and WT mice with subtle differences in gene expression

Neuropsychiatric disturbances (NPDs) are considered hallmarks of Alzheimer's disease (AD). Nevertheless, treatment of these symptoms has proven difficult and development of safe and effective treatment options is hampered by the limited understanding of the underlying pathophysiology. Thus, robust preclinical models are needed to increase knowledge of NPDs in AD and develop testable hypotheses and novel treatment options. Abnormal activity of the hypothalamic-pituitary-adrenal (HPA) axis is implicated in many psychiatric symptoms and might contribute to both AD and NPDs development and progression. We aimed to establish a mechanistic preclinical model of NPD-like behavior in the APPPS1 mouse model of AD and wildtype (WT) littermates. In APPPS1 and WT mice, we found that chronic stress increased anxiety-like behavior and altered diurnal locomotor activity suggestive of sleep disturbances. Also, chronic stress activated the HPA axis, which, in WT mice, remained heightened for additional 3 weeks. Chronic stress caused irregular expression of circadian regulatory clock genes (BMAL1, PER2, CRY1 and CRY2) in both APPPS1 and WT mice. Interestingly, APPPS1 and WT mice responded differently to chronic stress in terms of expression of serotonergic markers (5-HT_1A receptor and MAOA) and inflammatory genes (IL-6, STAT3 and ADMA17). These findings indicate that, although the behavioral response to chronic stress might be similar, the neurobiochemical response was different in APPPS1 mice, which is an important insight in the efforts to develop safe and effective treatments options for NPDs in AD patients. Further work is needed to substantiate these findings.

Acupuncture for Behavioral and Psychological Symptoms of Dementia: A Systematic Review and Meta-Analysis

Dementia is an important health issue worldwide, and non-pharmacological strategies for the management of behavioral and psychological symptoms of dementia (BPSD) are considered to be important. This review analyzes the effectiveness and safety of acupuncture for BPSD. Thirteen electronic databases were comprehensively searched to find clinical studies using acupuncture on BPSD, published up to December 2020. Five randomized controlled clinical trials and two before-after studies, mainly on Alzheimer’s disease (AD), were included. Meta-analysis suggested that the total effective rate based on BPSD symptoms in the acupuncture combined with psychotropic drugs group was significantly higher than that in the psychotropic drugs group (risk ratio, 1.27; 95% confidence interval, 1.11 to 1.45; I² = 51%). In terms of other outcomes related to BPSD, acupuncture as an adjunctive therapy, but not as monotherapy, was associated with significant benefits in most included studies. However, the included studies did not have optimal methodological quality. Our review highlights the limited evidence proving the effectiveness and safety of acupuncture for BPSD in patients with AD. Although some clinical studies have reported the potential benefits of adjuvant acupuncture in managing BPSD, the evidence is not robust and is based on small studies. Therefore, high-quality research in this field is needed.

A review of the mechanisms underlying selected comorbidities in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder of the central nervous system (CNS) leading to mental deterioration and devastation, and eventually a fatal outcome. AD affects mostly the elderly. AD is frequently accompanied by hypercholesterolemia, hypertension, atherosclerosis, and diabetes mellitus, and these are significant risk factors of AD. Other conditions triggered by the progression of AD include psychosis, sleep disorders, epilepsy, and depression. One important comorbidity is Down’s syndrome, which directly contributes to the severity and rapid progression of AD. The development of new therapeutic strategies for AD includes the repurposing of drugs currently used for the treatment of comorbidities. A better understanding of the influence of comorbidities on the pathogenesis of AD, and the medications used in its treatment, might allow better control of disease progression, and more effective pharmacotherapy.

Insights into the Pathophysiology of Psychiatric Symptoms in Central Nervous System Disorders: Implications for Early and Differential Diagnosis

Different psychopathological manifestations, such as affective, psychotic, obsessive-compulsive symptoms, and impulse control disturbances, may occur in most central nervous system (CNS) disorders including neurodegenerative and neuroinflammatory diseases. Psychiatric symptoms often represent the clinical onset of such disorders, thus potentially leading to misdiagnosis, delay in treatment, and a worse outcome. In this review, psychiatric symptoms observed along the course of several neurological diseases, namely Alzheimer’s disease, fronto-temporal dementia, Parkinson’s disease, Huntington’s disease, and multiple sclerosis, are discussed, as well as the involved brain circuits and molecular/synaptic alterations. Special attention has been paid to the emerging role of fluid biomarkers in early detection of these neurodegenerative diseases. The frequent occurrence of psychiatric symptoms in neurological diseases, even as the first clinical manifestations, should prompt neurologists and psychiatrists to share a common clinico-biological background and a coordinated diagnostic approach.

Different Morphology of Neuritic Plaques in the Archicortex of Alzheimer's Disease with Comorbid Synucleinopathy: A Pilot Study

BACKGROUND

Bulbous neuritic changes in neuritic plaques have already been described, and their possible effect on the clinical course of the disease has been discussed.

OBJECTIVE

In our study, we focused on the location and density of these structures in patients with only Alzheimer's disease (AD) and patients with AD in comorbidity with synucleinopathies.

METHODS

Utilizing immunohistochemistry and confocal microscopy, we evaluated differences of neocortical and archicortical neuritic plaques and the frequency of bulbous changes in the archicortex of 14 subjects with Alzheimer's disease (AD), 10 subjects with the Lewy body variant of Alzheimer's disease (AD/DLB), and 4 subjects with Alzheimer's disease with amygdala Lewy bodies (AD/ALB). Also, the progression and density of neuritic changes over the time course of the disease were evaluated.

RESULTS

We found structural differences in bulbous dystrophic neurites more often in AD/DLB and AD/ALB than in pure AD cases. The bulbous neuritic changes were more prominent in the initial and progressive phases and were reduced in cases with a long clinical course.

CONCLUSION

Our results indicate that there is a prominent difference in the shape and composition of neocortical and archicortical neuritic plaques and, moreover, that bulbous neuritic changes can be observed at a higher rate in AD/DLB and AD/ALB subjects compared to pure AD subjects. This observation probably reflects that these subacute changes are more easily seen in the faster clinical course of AD patients with comorbidities.

MicroRNA-138 Overexpression Alters Aβ42 Levels and Behavior in Wildtype Mice

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by changes in cognitive and behavioral functions. With the exception or rare mutations in PSEN and APP genes causing early-onset autosomal dominant AD (EOADAD), little is known about the genetic factors that underlie the vast majority (>95%) of early onset AD (EOAD) cases. We have previously identified copy number variations (CNVs) in microRNA genes in patients with EOAD, including a duplication of the MIR-138-2 gene. Overexpression of miR-138 in cultured cells increased Aβ production and tau phosphorylation, similar to what is seen in AD brain. In this study, we sought to determine if miR-138 overexpression could recapitulate certain features of disease in vivo in non-transgenic mice. A mild overexpression of pre-miR-138 in the brain of C57BL/6J wildtype mice altered learning and memory in a novel object recognition test and in the Barnes Maze. Increased levels of anxiety were also observed in the open-field test. MiR-138 upregulation in vivo caused an increase in endogenous Aβ42 production as well as changes in synaptic and inflammation markers. Tau expression was significantly lower with no overt effects on phosphorylation. We finally observed that Sirt1, a direct target of miR-138 involved in Aβ production, learning and memory as well as anxiety, is decreased following miR-138 overexpression. In sum, this study further strengthens a role for increased gene dosage of MIR-138-2 gene in modulating AD risk, possibly by acting on different biological pathways. Further studies will be required to better understand the role of CNVs in microRNA genes in AD and related neurodegenerative disorders.

Association Between BDNF Val66Met Polymorphism and Mild Behavioral Impairment in Patients With Parkinson's Disease

Neuropsychiatric symptoms (NPS) are common in Parkinson's disease (PD) and have demonstrated an association with the p. Val66Met, a polymorphism in the BDNF gene. Mild behavioral impairment (MBI) is a validated syndrome describing emergent and persistent NPS in older adults as a marker of potential cognitive decline and dementia. This study investigated if PD patients with the Met allele were more likely to have MBI and whether they had impairments in specific domains of MBI using the Mild Behavioral Impairment Checklist (MBI-C) as the MBI ascertainment tool. One hundred forty-six PD patients were screened for neuropsychiatric and cognitive impairments with the MBI-C and the Montreal Cognitive Assessment (MoCA). All participants were genotyped for the BDNF p.Val66Met single-nucleotide polymorphism (SNP) using TaqMan Genotyping Assay. Statistical analysis was performed using multiple linear and logistic regression models. Met carriers had a 2 times higher likelihood of being MBI positive (MBI-C total score ≥8) than Val carriers. Met carriers had significantly higher MBI-C total scores and significantly greater impairments in the mood/anxiety and the psychotic domains of MBI-C compared to Val carriers. These findings indicate that the BDNF Met allele is associated with a higher neuropsychiatric burden in PD.

New approaches to symptomatic treatments for Alzheimer's disease

BACKGROUND

Successful development of agents that improve cognition and behavior in Alzheimer's disease (AD) is critical to improving the lives of patients manifesting the symptoms of this progressive disorder.

DISCUSSION

There have been no recent approvals of cognitive enhancing agents for AD. There are currently 6 cognitive enhancers in Phase 2 trials and 4 in phase 3. They represent a variety of novel mechanisms. There has been progress in developing new treatments for neuropsychiatric symptoms in AD with advances in treatment of insomnia, psychosis, apathy, and agitation in AD. There are currently 4 AD-related psychotropic agents in Phase 2 trials and 7 in Phase 3 trials. Many novel mechanisms are being explored for the treatment of cognitive and behavioral targets. Progress in trial designs, outcomes measures, and population definitions are improving trial conduct for symptomatic treatment of AD.

CONCLUSIONS

Advances in developing new agents for cognitive and behavioral symptoms of AD combined with enhanced trial methods promise to address the unmet needs of patients with AD for improved cognition and amelioration of neuropsychiatric symptoms.

Subjective cognitive decline, anxiety symptoms, and the risk of mild cognitive impairment and dementia

BACKGROUND

Subjective cognitive decline (SCD) and anxiety symptoms both predict neurocognitive disorders, but the two correlate strongly with each other. It is unclear whether they reflect two independent disease processes in the development of neurocognitive disorders and hence deserve separate attention. This cohort study examined whether SCD and anxiety symptoms demonstrate independent risks of mild cognitive disorder and dementia (MCI/dementia).

METHODS

The study included 14,066 participants aged ≥ 50 years and diagnosed with normal cognition at baseline, recruited from Alzheimer's Disease Centers across the USA. The participants were evaluated for SCD and anxiety symptoms at baseline and followed up almost annually for incident MCI/dementia (median follow-up 4.5 years; interquartile range 2.2-7.7 years). SCD and anxiety symptoms were included in Cox regression to investigate their independent risks of MCI/dementia.

RESULTS

SCD and anxiety symptoms demonstrated independent risks of MCI/dementia, with HR 1.9 (95% CI 1.7-2.1) and 1.3 (95% CI 1.2-1.5), respectively. Co-occurring SCD and anxiety symptoms demonstrated the highest risk (HR 2.4, 95% CI 1.9-2.9)-participants in this group had a 25% probability of developing MCI/dementia by 3.1 years (95% 2.4-3.7), compared to 8.2 years among those without SCD or anxiety (95% CI 7.9-8.6). The results remained robust even in the sensitivity analyses that took into account symptom severity and consistency of symptoms in the first 2 annual visits.

CONCLUSIONS

The findings suggest that clinicians should not dismiss one over the other when patients present with both SCD and anxiety and that both constructs may potentially be useful to identify high-risk populations for preventive interventions and trials. The findings also point to the need for further research to clarify on the neurobiological distinctions between SCD and anxiety symptoms, which may potentially enrich our understanding on the pathogenesis of neurocognitive disorders.

New antipsychotic drugs for the treatment of agitation and psychosis in Alzheimer's disease: focus on brexpiprazole and pimavanserin

Behavioral and psychological symptoms of dementia are symptoms of disturbed perception, mood, behavior, and thought content that occurred frequently. These symptoms, which include apathy, depression, anxiety, psychosis, agitation, and aggression, can serve as predictors of and early clinical diagnostic markers for Alzheimer's disease (AD) and are common precipitants of institutional care. Agitation and psychosis are associated with accelerated disease progression and increased tau phosphorylation in patients with AD. Current guidelines recommend the use of second-generation antipsychotics for the treatment of agitation and psychosis in AD, but only after first-line non-pharmacological interventions and for no longer than 12 weeks because long-term use of these drugs is associated with an increased risk of mortality and an increased frequency of cerebrovascular events. Therefore, new antipsychotic drugs with improved efficacy and safety are needed as an alternative to current antipsychotic drugs. In this report, we discuss some of the most relevant advances in the field of agitation and psychosis in AD and focus on the recent positive clinical evidence observed with two new antipsychotics drugs: brexpiprazole and pimavanserin. Brexpiprazole is a receptor partial agonist (D2, D3, 5-HT1A), receptor antagonist (5-HT2A/B, α1B/α2C) according to the neuroscience-based nomenclature. Two recent phase III clinical trials have shown that brexpiprazole 2 mg/day is effective for the treatment of agitation in patients with AD and has an improved tolerability and safety profile compared with currently available second-generation antipsychotics. Pimavanserin is a receptor antagonist (5-HT2A, 5-HT2C) that has been given market authorization for psychosis occurring in Parkinson's disease. Recent phase II studies suggest that this drug is effective in AD patients with more severe psychosis, although further long-term studies are needed to better define the efficacy and long-term safety profile of pimavanserin for the treatment of psychosis in AD.

The Association Between Biomarkers and Neuropsychiatric Symptoms Across the Alzheimer's Disease Spectrum

OBJECTIVE

To investigate the relationship between Alzheimer's disease biomarkers and neuropsychiatric symptoms.

METHODS

Data from two large cohort studies, the Dutch Parelsnoer Institute - Neurodegenerative Diseases and the Alzheimer's Disease Neuroimaging Initiative was used, including subjects with subjective cognitive decline (N = 650), mild cognitive impairment (N = 887), and Alzheimer's disease dementia (N = 626). Cerebrospinal fluid (CSF) levels of Aβ₄₂, t-tau, p-tau, and hippocampal volume were associated with neuropsychiatric symptoms (measured with the Neuropsychiatric Inventory) using multiple logistic regression analyses. The effect of the Mini-Mental State Examination (as proxy for cognitive functioning) on these relationships was assessed with mediation analyses.

RESULTS

Alzheimer's disease biomarkers were not associated with depression, agitation, irritability, and sleep disturbances. Lower levels of CSF Aβ₄₂, higher levels of t- and p-tau were associated with presence of anxiety. Lower levels of CSF Aβ₄₂ and smaller hippocampal volumes were associated with presence of apathy. All associations were mediated by cognitive functioning.

CONCLUSION

The association between Alzheimer's disease pathology and anxiety and apathy is partly due to impairment in cognitive functioning.

Steps Towards Developing Effective Treatments for Neuropsychiatric Disturbances in Alzheimer's Disease: Insights From Preclinical Models, Clinical Data, and Future Directions

Alzheimer's disease (AD) is the most common form of dementia worldwide. It is mostly known for its devastating effect on memory and learning but behavioral alterations commonly known as neuropsychiatric disturbances (NPDs) are also characteristics of the disease. These include apathy, depression-like behavior, and sleep disturbances, and they all contribute to an increased caregiver burden and earlier institutionalization. The interaction between NPDs and AD pathology is not well understood, but the consensus is that they contribute to disease progression and faster decline. Consequently, recognizing and treating NPDs might improve AD pathology and increase the quality of life for both patients and caregivers. In this review article, we examine previous and current literature on apathy, depressive symptoms, and sleep disturbances in AD patients and preclinical AD mechanistic models. We hypothesize that tau accumulation, beta-amyloid (Aβ) aggregation, neuroinflammation, mitochondrial damage, and loss of the locus coeruleus (LC)-norepinephrine (NE) system all collectively impact the development of NPDs and contribute synergistically to AD pathology. Targeting more than one of these processes might provide the most optimal strategy for treating NPDs and AD. The development of such clinical approaches would be preceded by preclinical studies, for which robust and reliable mechanistic models of NPD-like behavior are needed. Thus, developing effective preclinical research models represents an important step towards a better understanding of NPDs in AD.

Synthesis of Novel Nicotinic Ligands with Multimodal Action: Targeting Acetylcholine α4β2, Dopamine and Serotonin Transporters

Nicotinic acetylcholine receptors (nAChRs), serotonin transporters (SERT) and dopamine transporters (DAT) represent targets for the development of novel nicotinic derivatives acting as multiligands associated with different health conditions, such as depressive, anxiety and addiction disorders. In the present work, a series of functionalized esters structurally related to acetylcholine and nicotine were synthesized and pharmacologically assayed with respect to these targets. The synthesized compounds were studied in radioligand binding assays at α4β2 nAChR, h-SERT and h-DAT. SERT experiments showed not radioligand [³H]-paroxetine displacement, but rather an increase in the radioligand binding percentage at the central binding site was observed. Compound 20 showed K_i values of 1.008 ± 0.230 μM for h-DAT and 0.031 ± 0.006 μM for α4β2 nAChR, and [³H]-paroxetine binding of 191.50% in h-SERT displacement studies, being the only compound displaying triple affinity. Compound 21 displayed K_i values of 0.113 ± 0.037 μM for α4β2 nAChR and 0.075 ± 0.009 μM for h-DAT acting as a dual ligand. Molecular docking studies on homology models of α4β2 nAChR, h-DAT and h-SERT suggested potential interactions among the compounds and agonist binding site at the α4/β2 subunit interfaces of α4β2 nAChR, central binding site of h-DAT and allosteric modulator effect in h-SERT.

Neuropsychiatric Symptoms as Predictors of Clinical Course in Neurodegeneration. A Longitudinal Study

Background: To study the extent to which neuropsychiatric symptoms (NPS) influence the cognitive and functional decline in frontotemporal degeneration (FTD) and Alzheimer’s disease (AD).

Methods: We assessed the progression of NPS and their influence on cognitive and functional progression in a group of FTD (n = 36) and AD patients (n = 47) at two different stages of the disease (2.5 years). A standardized scale was used to assess NPS—the Columbia University Scale for Psychopathology in Alzheimer’s Disease (CUSPAD)—which tracks different symptoms including depression, psychotic symptoms, as well as sleep and conduct problems. In addition, in a subsample of patients (AD n = 14 and FTD n = 14), we analyzed another group of NPS by using the Neuropsychiatric Inventory (NPI). Cognitive declines were tracked by using the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), while functionality was tracked by using the Lawton scale and the Barthel Index.

Results: The presence of NPS impacts cognitive and functional decline in both groups of patients 2.5 years after disease onset. However, we observed a dissociable profile of the affectation of NPS in each group. In the AD group, results indicate that the progression of depressive symptoms and sleep problems predict cognitive and functional decline. In contrast, the progression of a mixed group of NPS, including conduct problems and delusions, predicts cognitive and functional decline in FTD.

Conclusion: The presence of NPS has a critical impact on the prediction of cognitive decline in FTD and AD patients after 2.5 years of disease progression. Our results demonstrate the importance of assessing different types of NPS in neurodegenerative disorders which, in turn, predict disease progression. Future studies should assess the role of NPS in predicting different neurocognitive pathways and in neurodegeneration.

Prediction of Autopsy Verified Neuropathological Change of Alzheimer's Disease Using Machine Learning and MRI

Background: Alzheimer’s disease (AD) is the most common form of dementia. While neuropathological changes pathognomonic for AD have been defined, early detection of AD prior to cognitive impairment in the clinical setting is still lacking. Pioneer studies applying machine learning to magnetic-resonance imaging (MRI) data to predict mild cognitive impairment (MCI) or AD have yielded high accuracies, however, an algorithm predicting neuropathological change is still lacking. The objective of this study was to compute a prediction model supporting a more distinct diagnostic criterium for AD compared to clinical presentation, allowing identification of hallmark changes even before symptoms occur.

Methods: Autopsy verified neuropathological changes attributed to AD, as described by a combined score for Aβ-peptides, neurofibrillary tangles and neuritic plaques issued by the National Institute on Aging – Alzheimer’s Association (NIAA), the ABC score for AD, were predicted from structural MRI data with RandomForest (RF). MRI scans were performed at least 2 years prior to death. All subjects derive from the prospective Vienna Trans-Danube Aging (VITA) study that targeted all 1750 inhabitants of the age of 75 in the starting year of 2000 in two districts of Vienna and included irregular follow-ups until death, irrespective of clinical symptoms or diagnoses. For 68 subjects MRI as well as neuropathological data were available and 49 subjects (mean age at death: 82.8 ± 2.9, 29 female) with sufficient MRI data quality were enrolled for further statistical analysis using nested cross-validation (CV). The decoding data of the inner loop was used for variable selection and parameter optimization with a fivefold CV design, the new data of the outer loop was used for model validation with optimal settings in a fivefold CV design. The whole procedure was performed ten times and average accuracies with standard deviations were reported.

Results: The most informative ROIs included caudal and rostral anterior cingulate gyrus, entorhinal, fusiform and insular cortex and the subcortical ROIs anterior corpus callosum and the left vessel, a ROI comprising lacunar alterations in inferior putamen and pallidum. The resulting prediction models achieved an average accuracy for a three leveled NIAA AD score of 0.62 within the decoding sets and of 0.61 for validation sets. Higher accuracies of 0.77 for both sets, respectively, were achieved when predicting presence or absence of neuropathological change.

Conclusion: Computer-aided prediction of neuropathological change according to the categorical NIAA score in AD, that currently can only be assessed post-mortem, may facilitate a more distinct and definite categorization of AD dementia. Reliable detection of neuropathological hallmarks of AD would enable risk stratification at an earlier level than prediction of MCI or clinical AD symptoms and advance precision medicine in neuropsychiatry.

The course of neuropsychiatric symptoms in nursing home residents from admission to 30-month follow-up

Aim

The aim of this study was to describe the prevalence and persistence of clinically significant neuropsychiatric symptoms (NPS) in nursing home residents with dementia, and to study the association between severity of dementia and specific neuropsychiatric sub-syndromes over time.

Methods

In total, 583 residents with dementia were included at admission to a nursing home and followed with biannual assessments until death, or to 30-month follow-up. At the end of the 30-month follow-up, 305 participants had died and 57 had left the study for other reasons, leaving 221 residents in the study. We collected data on demographics, cognition, severity of dementia, NPS, personal activities of daily living (P-ADL), physical health, medication and type of nursing home unit. NPS was assessed using the Neuropsychiatric Inventory (NPI), the Nursing Home version.

Results

The prevalence and persistence at two consecutive time-points of clinically significant NPS was high during the study period. The mean NPI agitation sub-syndrome score increased during the study period, while the NPI affective and psychosis sub-syndrome scores remained unchanged. More severe dementia was associated with higher NPI agitation, psychosis and affective sub-syndrome scores. The association remained unchanged over time for agitation and psychosis. For the NPI affective sub-syndrome, the association was stronger at the beginning, and declined towards the end of the study period.

Conclusion

The findings of high prevalence and persistence at two consecutive time points of clinically significant NPS over time, and the associations between severity of dementia and NPI sub-syndromes shed light on the burden and care needs of nursing home residents with dementia after admission to nursing home care. This information is of interest to health care planners and providers to enable them to increase the quality of care for nursing home residents.

Neuropsychiatric Symptoms and Caregiver Burden in Individuals With Alzheimer's Disease: The TEAM-AD VA Cooperative Study

OBJECTIVES

To assess the prevalence of neuropsychiatric symptoms (NPS) in mild-to-moderate Alzheimer disease (AD) and their association with caregiver burden.

METHODS

Secondary analyses of baseline data from the Trial of Vitamin E and Memantine in Alzheimer's Disease (TEAM-AD) (N=613). Neuropsychiatric Inventory were used to measure severity of NPS and caregiver activity survey to measure caregiver burden.

RESULTS

A total of 87% of patients displayed at least 1 NPS; 70% displayed clinically meaningful NPS. The most common symptoms were apathy (47%), irritability (44%), agitation (42%), and depression (40%). Those with moderate AD had more severe NPS than those with mild AD ( P = .03). Neuropsychiatric symptoms were significantly associated with caregiver time after adjusting for age, education, cognitive function, and comorbidity ( P-value < .0001) with every point increase in NPS associated with a 10-minute increase in caregiver time.

CONCLUSION

Neuropsychiatric symptoms were prevalent in both mild and moderate AD, even in patients receiving treatment with an acetylcholinesterase inhibitors, and were more severe in moderate AD and associated with greater caregiver time.

Nanomedicine and Phage Capsids

Studies of phage capsids have at least three potential interfaces with nanomedicine. First, investigation of phage capsid states potentially will provide therapies targeted to similar states of pathogenic viruses. Recently detected, altered radius-states of phage T3 capsids include those probably related to intermediate states of DNA injection and DNA packaging (dynamic states). We discuss and test the idea that some T3 dynamic states include extensive α-sheet in subunits of the capsid’s shell. Second, dynamic states of pathogenic viral capsids are possible targets of innate immune systems. Specifically, α-sheet-rich innate immune proteins would interfere with dynamic viral states via inter-α-sheet co-assembly. A possible cause of neurodegenerative diseases is excessive activity of these innate immune proteins. Third, some phage capsids appear to have characteristics useful for improved drug delivery vehicles (DDVs). These characteristics include stability, uniformity and a gate-like sub-structure. Gating by DDVs is needed for (1) drug-loading only with gate opened; (2) closed gate-DDV migration through circulatory systems (no drug leakage-generated toxicity); and (3) drug release only at targets. A gate-like sub-structure is the connector ring of double-stranded DNA phage capsids. Targeting to tumors of phage capsid-DDVs can possibly be achieved via the enhanced permeability and retention effect.

Hypothesis for the cause and therapy of neurodegenerative diseases

The cause and therapy of neurodegenerative diseases remain unsolved puzzles. These diseases are correlated with presence of beta sheet-rich amyloid assemblies. Here, I derive and assemble puzzle pieces to obtain a loose end-tying hypothesis for cause with direct implications for therapy. I use the following extrapolations to find connectable puzzle pieces: (a) the traditional extrapolation that amyloid/amyloid precursors cause disease, (b) a recent extrapolation that amyloid-forming proteins, some of which are virus protein homologs, are components of an empirically obscure innate immune system that counters insults, including those by both viruses and bacteria, (c) a new extrapolation that various insults produce assemblies with structural features in common and that amyloid-forming, innate immune system proteins recognize these features and, then, counter insults by co-assembly, (d, 1) a second new extrapolation that beta sheet is a common structural feature and is extended during insult-neutralizing co-assembly and (d, 2) an appendix, derived from studies of phages T3 and T4, that most insult-produced assemblies are obscure to current biochemical analysis. The hypothesis is the following. One function of amyloid-forming proteins is non-classical innate immunity to biological insults. This immunity works via beta sheet-extending co-assembly of amyloid-forming proteins with beta sheet-containing insult products. For example, co-assembly with beta sheet-containing viral assembly intermediates inhibits virus production. Amyloid-forming proteins cause neurodegenerative disease when errant, typically overproduced. Other innate immunity systems sometimes exacerbate symptoms. This hypothesis suggests the following therapy, based on manipulating Nature's chemistry. First, conduct directed evolution to obtain low-pathogenicity, chronic symptom-producing viruses with assembly intermediates that co-assemble with and destabilize both amyloid and amyloid sub-assemblies. Then, infect patients with these viruses.

Sleep and Alzheimer's disease: A pivotal role for the suprachiasmatic nucleus

Alzheimer's disease (AD), which accounts for most of the dementia cases, is, aside from cognitive deterioration, often characterized by the presence of non-cognitive symptoms. Society is desperately in need for interventions that alleviate the economic and social burden related to AD. Circadian dysrhythmia, one of these symptoms in particular, immensely decreases the self-care ability of AD patients and is one of the main reasons of caregiver exhaustion. Studies suggest that these circadian disturbances form the root of sleep-wake problems, diagnosed in more than half of AD patients. Sleep abnormalities have generally been considered merely a consequence of AD pathology. Recent evidence suggests that a bidirectional relationship exists between sleep and AD, and that poor sleep might negatively impact amyloid burden, as well as cognition. The suprachiasmatic nucleus (SCN), the main circadian pacemaker, is subjected to several alterations during the course of the disease. Its functional deterioration might fulfill a crucial role in the relation between AD pathophysiology and the development of sleep abnormalities. This review aims to give a concise overview of the anatomy and physiology of the SCN, address how AD pathology precisely impacts the SCN and to what degree these alterations can contribute to the progression of the disease.

An update on the advancements in the treatment of agitation in Alzheimer's disease

INTRODUCTION

Neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) are associated with significant negative outcomes for patients and their caregivers. Agitation, one of the most distressing NPS, lacks safe and effective long term interventions. Nonpharmacological interventions are suggested as first-line treatment, but aren't effective for every patient, resulting in pharmacological interventions for some patients, consisting of off-label use of antipsychotics, sedative/hypnotics, anxiolytics, acetylcholinesterase inhibitors, memantine, and antidepressants; where efficacy doesn't necessarily outweigh associated risks. Areas covered: Gains in understanding neurobiological mechanisms underlying agitation have fueled several recent clinical trials. This article updates our review published in 2014. Comprehensive literature search for published articles from January 2014 to December 2016 evaluating pharmacologic interventions for agitation in AD was done. A review of several clinical trials was completed: dextromethorphan/quinidine, scyllo-inositol, brexpiprazole, prazosin, cannabinoids, citalopram, escitalopram, pimavanserin, ITI-007, ORM-12741 show promise in treating agitation. Expert opinion: Neurobiological findings, innovative trials designs, statistical approaches, and preliminary paths for regulatory agency acceptance have re-ignited the area of pharmacological treatment of NPS. Though further research is needed to fully determine the safety, tolerability and efficacy of these treatments, the mission to find effective treatments for neuropsychiatric symptoms such as agitation in patients with dementia is well underway.

Recent advances in the management of neuropsychiatric symptoms in dementia

PURPOSE OF REVIEW

The present article addresses intriguing questions related to the clinical intervention in distinct neuropsychiatric syndromes of patients with dementia.

RECENT FINDINGS

We reviewed 154 articles published between 2015 and 2016 targeting psychopharmacological and nonpharmacological interventions, and safety-tolerability concerns. We selected 115 articles addressing the purpose of this study. Of these, 33 were chosen because they were dedicated to subtopics: agitation (42), depression (33), apathy (18), sleep disorders/anxiety (8), and psychosis (4). Clinical studies using both pharmacological (70) and nonpharmacological (37) interventions were considered; others were included for theoretical support. Regarding the methodological design, we found double-blind RCTs (17), single-blinded RCTs (4), open-label studies (18), case reports (5), cross-sectional or cohort studies (25), epidemiological papers (2), and expert reviews (44). This observation raises concerns about the overall methodological adequacy of a substantial proportion of studies in this field, which limits the potential of generalization of the findings. Finally, 18 studies were designed to determine safety-tolerability issues of psychotropic medications (6 were discussed).

SUMMARY

Effective and well tolerated treatment of neuropsychiatric syndromes in dementia remains a critically unsolved challenge. We understand that this is an extremely important area of research, and critically required to guide clinical decisions in geriatric neuropsychiatry.