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

Impairment of hippocampal astrocyte-mediated striatal dopamine release and locomotion in Alzheimer's disease

BACKGROUND

Clinical and translational research has identified deficits in the dopaminergic neurotransmission in the striatum in Alzheimer's disease (AD) and this could be related to the pathophysiology of psychiatric symptoms appearing even at early stages of the pathology.

HYPOTHESIS

We hypothesized that AD pathology in the hippocampus may influence dopaminergic neurotransmission even in the absence of AD-related lesion in the mesostriatal circuit.

METHODS

We chemogenetically manipulated the activity of hippocampal neurons and astrocytes in wild-type and hemizygous TgF344-AD (Tg) rats, an animal model of AD pathology. We assessed the brain-wide functional output of this manipulation using in vivo Single Photon Emission Computed Tomography to measure cerebral blood flow and D2/3 receptor binding, in response to acute (3 mg kg-1 i.p.) and chronic (0.015 mg/ml in drinking water, 28 days) stimulation of neurons or astrocytes with clozapine N-oxide. We also assessed the effects of the chronic chemogenetic manipulations on D2 receptor density, low or high aggregated forms of amyloid Aβ40 and Aβ42, astrocytes and microglial reactivity, and the capacity of astrocytes and microglia to surround and phagocytize Aβ both locally and in the striatum.

RESULTS

We showed that acute and chronic neuronal and astrocytic stimulation induces widespread effects on the brain regional activation pattern, notably with an inhibition of striatal activation. In the Tg rats, both these effects were blunted. Chemogenetic stimulation in the hippocampus increased microglial density and its capacity to limit AD pathology, whereas these effects were absent in the striatum perhaps as a consequence of the altered connectivity between the hippocampus and the striatum.

CONCLUSIONS

Our work suggests that hippocampal AD pathology may alter mesostriatal signalling and induce widespread alterations of brain activity. Neuronal and astrocytic activation may induce a protective, Aβ-limiting phenotype of microglia, which surrounds Aβ plaques and limits Αβ concentration more efficiently.

Olanzapine attenuates amyloid-β-induced microglia-mediated progressive neurite lesions

The accumulation of amyloid-β (Aβ) in the brain is the first pathological mechanism to initiate Alzheimer's disease (AD) pathogenesis. However, the precise role of Aβ in the disease progression remains unclear. Through decades of research, prolonged inflammation has emerged as an important core pathology in AD. Previously, a study has demonstrated the neurotoxic effect of Aβ-induced neuroinflammation in neuron-glia co-culture at 72 h. Here, we hypothesise that initial stage Aβ may trigger microglial inflammation, synergistically contributing to the progression of neurite lesions relevant to AD progression. In the present study, we aimed to determine whether olanzapine, an antipsychotic drug possessing anti-inflammatory properties, can ameliorate Aβ-induced progressive neurite lesions. Our study reports that Aβ induces neurite lesions with or without inflammatory microglial cells in vitro. More intriguingly, the present study revealed that Aβ exacerbates neurite lesions in synergy with microglia. Moreover, the time course study revealed that Aβ promotes microglia-mediated neurite lesions by eliciting the secretion of pro-inflammatory cytokines. Furthermore, our study shows that olanzapine at lower doses prevents Aβ-induced microglia-mediated progressive neurite lesions. The increase in pro-inflammatory cytokines induced by Aβ is attenuated by olanzapine administration, associated with a reduction in microglial inflammation. Finally, this study reports that microglial senescence induced by Aβ was rescued by olanzapine. Thus, our study provides the first evidence that 1 µM to 5 µM of olanzapine can effectively prevent Aβ-induced microglia-mediated progressive neurite lesions by modulating microglial inflammation. These observations reinforce the potential of targeting microglial remodelling to slow disease progression in AD.

A Comprehensive Exploration of the Multifaceted Neuroprotective Role of Cannabinoids in Alzheimer's Disease across a Decade of Research

Alzheimer's disease (AD), a progressive neurodegenerative disorder, manifests through dysregulation of brain function and subsequent loss of bodily control, attributed to β-amyloid plaque deposition and TAU protein hyperphosphorylation and aggregation, leading to neuronal death. Concurrently, similar cannabinoids to the ones derived from Cannabis sativa are present in the endocannabinoid system, acting through receptors CB1R and CB2R and other related receptors such as Trpv-1 and GPR-55, and are being extensively investigated for AD therapy. Given the limited efficacy and adverse effects of current available treatments, alternative approaches are crucial. Therefore, this review aims to identify effective natural and synthetic cannabinoids and elucidate their beneficial actions for AD treatment. PubMed and Scopus databases were queried (2014-2024) using keywords such as "Alzheimer's disease" and "cannabinoids". The majority of natural (Δ9-THC, CBD, AEA, etc.) and synthetic (JWH-133, WIN55,212-2, CP55-940, etc.) cannabinoids included showed promise in improving memory, cognition, and behavioral symptoms, potentially via pathways involving antioxidant effects of selective CB1R agonists (such as the BDNF/TrkB/Akt pathway) and immunomodulatory effects of selective CB2R agonists (TLR4/NF-κB p65 pathway). Combining anticholinesterase properties with a cannabinoid moiety may enhance therapeutic responses, addressing cholinergic deficits of AD brains. Thus, the positive outcomes of the vast majority of studies discussed support further advancing cannabinoids in clinical trials for AD treatment.

The treatment of behavioural and psychological symptoms in dementia: pragmatic recommendations

Behavioural and psychological symptoms of dementia (BPSD) are a clinical challenge for the lack of a sound taxonomy, frequent presentation with comorbid BPSD, lack of specific pharmacologic interventions, poor base of methodologically sound evidence with randomized clinical trials, contamination from the treatment of behavioural disturbances of young and adult psychiatric conditions, and small efficacy window of psychotropic drugs. We present here a treatment workflow based on a concept-driven literature review based on the notions that (i) the aetiology of BPSD can be mainly neurobiological (so-called 'primary' symptoms) or mainly environmental and functional ('secondary' symptoms) and that this drives treatment; (ii) the clinical efficacy of psychotropic drugs is driven by their specific profile of receptor affinity; (iii) drug treatment should follow the rules of 'start low-go slow, prescribe and revise'. This article argues in support of the distinction between primary and secondary BPSD, as well as their characteristics, which until now have been just sketchily described in the literature. It also offers comprehensive and pragmatic clinician-oriented recommendations for the treatment of BPSD.

Application of CRISPR/Cas9 System in the Treatment of Alzheimer's Disease and Neurodegenerative Diseases

Alzheimer's, Parkinson's, and Huntington's are some of the most common neurological disorders, which affect millions of people worldwide. Although there have been many treatments for these diseases, there are still no effective treatments to treat or completely stop these disorders. Perhaps the lack of proper treatment for these diseases can be related to various reasons, but the poor results related to recent clinical research also prompted doctors to look for new treatment approaches. In this regard, various researchers from all over the world have provided many new treatments, one of which is CRISPR/Cas9. Today, the CRISPR/Cas9 system is mostly used for genetic modifications in various species. In addition, by using the abilities available in the CRISPR/Cas9 system, researchers can either remove or modify DNA sequences, which in this way can establish a suitable and useful treatment method for the treatment of genetic diseases that have undergone mutations. We conducted a non-systematic review of articles and study results from various databases, including PubMed, Medline, Web of Science, and Scopus, in recent years. and have investigated new treatment methods in neurodegenerative diseases with a focus on Alzheimer's disease. Then, in the following sections, the treatment methods were classified into three groups: anti-tau, anti-amyloid, and anti-APOE regimens. Finally, we discussed various applications of the CRISPR/Cas-9 system in Alzheimer's disease. Today, using CRISPR/Cas-9 technology, scientists create Alzheimer's disease models that have a more realistic phenotype and reveal the processes of pathogenesis; following the screening of defective genes, they establish treatments for this disease.

Neurodegenerative Diseases: New Hopes and Perspectives

Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Huntington's disease, and Friedrich ataxia are all incurable neurodegenerative diseases defined by the continuous progressive loss of distinct neuronal subtypes. Despite their rising prevalence among the world's ageing population, fewer advances have been made in the concurrent massive efforts to develop newer drugs. Recently, there has been a shift in research focus towards the discovery of new therapeutic agents for neurodegenerative diseases. In this review, we have summarized the recently developed therapies and their status in the management of neurodegenerative diseases.

The Janus face of antipsychotics in glial cells: Focus on glioprotection

Antipsychotics are commonly prescribed to treat several neuropsychiatric disorders, including schizophrenia, mania in bipolar disorder, autism spectrum disorder, delirium, and organic or secondary psychosis, for example, in dementias such as Alzheimer's disease. There is evidence that typical antipsychotics such as haloperidol are more effective in reducing positive symptoms than negative symptoms and/or cognitive deficits. In contrast, atypical antipsychotic agents have gained popularity over typical antipsychotics, due to fewer extrapyramidal side effects and their theoretical efficacy in controlling both positive and negative symptoms. Although these therapies focus on neuron-based therapeutic schemes, glial cells have been recognized as important regulators of the pathophysiology of neuropsychiatric disorders, as well as targets to improve the efficacy of these drugs. Glial cells (astrocytes, oligodendrocytes, and microglia) are critical for the central nervous system in both physiological and pathological conditions. Astrocytes are the most abundant glial cells and play important roles in brain homeostasis, regulating neurotransmitter systems and gliotransmission, since they express a wide variety of functional receptors for different neurotransmitters. In addition, converging lines of evidence indicate that psychiatric disorders are commonly associated with the triad neuroinflammation, oxidative stress, and excitotoxicity, and that glial cells may contribute to the gliotoxicity process. Conversely, glioprotective molecules attenuate glial damage by generating specific responses that can protect glial cells themselves and/or neurons, resulting in improved central nervous system (CNS) functioning. In this regard, resveratrol is well-recognized as a glioprotective molecule, including in clinical studies of schizophrenia and autism. This review will provide a summary of the dual role of antipsychotics on neurochemical parameters associated with glial functions and will highlight the potential activity of glioprotective molecules to improve the action of antipsychotics.

G protein-coupled receptors in neurodegenerative diseases and psychiatric disorders

Neuropsychiatric disorders are multifactorial disorders with diverse aetiological factors. Identifying treatment targets is challenging because the diseases are resulting from heterogeneous biological, genetic, and environmental factors. Nevertheless, the increasing understanding of G protein-coupled receptor (GPCR) opens a new possibility in drug discovery. Harnessing our knowledge of molecular mechanisms and structural information of GPCRs will be advantageous for developing effective drugs. This review provides an overview of the role of GPCRs in various neurodegenerative and psychiatric diseases. Besides, we highlight the emerging opportunities of novel GPCR targets and address recent progress in GPCR drug development.

An Intervention on Anxiety Symptoms in Moderate Alzheimer's Disease through Virtual Reality: A Feasibility Study and Lessons Learned

(1) Background: Although cognitive impairment is considered the core deficit of dementia, anxiety disorders also have a negative influence on the social and daily life of the affected population. We have explored the exposure of relaxing scenarios in immersive Virtual Reality (iVR) as an intervention strategy for people with moderate Alzheimer's disease. (2) Methods: Three participants were recruited from a day center to participate in a five-week study, which included a Pre- and Post-evaluation with the Montreal Cognitive Assessment (MoCA), Neuropsychiatric Inventory-Questionnaire (NPI-Q), Clinical Dementia Rating Scale (CDR), Global Deterioration Scale (GDS), Hamilton Anxiety Rating Scale (HARS), State-Trait Anxiety Inventory (STAI), and the anxiety subdomain of the Neuropsychiatric Inventory (NPI). Participants' heart rate, oxygen saturation, arterial pressure, and respiratory rate were also monitored during intervention sessions. Three virtual scenarios from Nature Treks VR were used as the intervention over three weeks (a total of nine sessions). (3) Results: Post-intervention anxiety assessment showed a light reduction in psychological anxiety in the HARS questionnaire. A light reduction in heart rate was also observed during the exposure to iVR. (4) Discussion: The use of virtual scenarios was a satisfactory experience for all the participants. Preliminary data point to a relaxing effect of iVR scenarios and a potential reduction in psychological anxiety, but further research is required to confirm the efficacy of the intervention.

A New Hope in Alzheimer's Disease Psychosis: Pimavanserin

Alzheimer's disease (AD) ranks first among the causes of dementia worldwide. AD can develop a psychotic manifest at a significant rate. AD prognosis worsens by added psychosis clinic. There is no treatment approved by the United States Food and Drug Administration (FDA) among antipsychotics for Alzheimer's disease Psychosis (ADP). However, pimavanserine, an atypical antipsychotic, has been approved by the FDA for Parkinson's psychosis. It is predicted that pimavanserin, a new antipsychotic, will fill an important gap in this area. In clinical trials, it appears to be effective in the treatment of delusions and hallucinations at psychosis in both Parkinson's and AD. In this systematic review, we evaluated the analysis of current literature data on pimavanserin used in ADP. We searched the existing literature on clinical studies on pimavanserin therapy used in ADP. Data were determined by systematically searching PubMed, MEDLINE, EMBASE, and Google Scholar until December 2022. A total of 35 citations were found and uploaded on the Mendeley program. Abstracts and full texts of literature data were examined. Pimavanserin was observed, and satisfactory results were obtained in treating ADP. Pimavanserin has a unique mechanism of action. Pimavanserin, an atypical antipsychotic drug, has a low affinity for 5-HT2C receptors and has selective 5-HT2A reverse agonist/antagonist action. Pimavanserin has no clinically significant affinity for dopaminergic, histaminergic, muscarinic or adrenergic receptors. This agent may also achieve significant positive results in resistant psychosis treatments.

Alzheimer's Disease: Understanding Its Novel Drug Delivery Systems and Treatments

Around the world, there are no fewer than 24 million people who suffer from dementia. Through 2040, this number is expected to rise steadily every 20 years. Alzheimer's disease (AD), the most prevalent kind of dementia, is characterised by a steady deterioration in cognitive function that most often begins with memory loss. Alzheimer's disease (AD) is considered to be one of the leading causes of morbidity in the elderly. Around 5 million people in the United States have Alzheimer's disease. Still, because AD is common in the older and greying population, its prevalence is expected to rise dramatically in the coming decades. As the disease progresses, people with Alzheimer's disease frequently become dependent on caregivers. The Alzheimer's-diseased brain is characterised neuropathologically by diffuse and neuritic extracellular amyloid plaques, which are often ringed by dystrophic neurites and intracellular neurofibrillary tangles. This particular disease is characterised by the presence of reactive microgliosis and the destruction of neurons, white matter, and synapses. The present review is done to study and learn about new treatments and novel drug delivery systems that may provide benefits to patients with AD. With the new drugs, treatments, constant care requirements, and lost productivity, Alzheimer's has a substantial financial impact on society. Therefore, better management and therapy are crucial. In this overview, we will briefly go through the current knowledge base about AD, covering the functions of beta-amyloid, tau proteins, and stem cell therapy, and elaborating on novel diagnostic and therapeutic interventions.

Treatment of dementia: recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

ABSTRACT There is currently no cure for neurodegenerative or vascular dementias, but some pharmacological and non-pharmacological interventions may contribute to alleviate symptoms, slow disease progression and improve quality of life. Current treatment approaches are based on etiology, symptom profile and stage of dementia. This manuscript presents recommendations on pharmacological and non-pharmacological treatments of dementia due to Alzheimer’s disease, vascular cognitive impairment, frontotemporal dementia, Parkinson’s disease dementia, and dementia with Lewy bodies.

Tratamento da demência: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia

RESUMO Atualmente não há tratamento curativo para as demências neurodegenerativas ou para a demência vascular, mas algumas intervenções farmacológicas e não farmacológicas podem contribuir para aliviar os sintomas, retardar a progressão da doença e melhorar a qualidade de vida. As abordagens terapêuticas atuais são baseadas na etiologia, no perfil dos sintomas e no estágio da demência. Neste artigo apresentamos recomendações sobre os tratamentos farmacológicos e não farmacológicos da demência devida à doença de Alzheimer, comprometimento cognitivo vascular, demência frontotemporal, demência da doença de Parkinson e demência com corpos de Lewy.

Atypical Antipsychotics and Metabolic Syndrome: From Molecular Mechanisms to Clinical Differences

Atypical antipsychotics (AAPs) are commonly prescribed medications to treat schizophrenia, bipolar disorders and other psychotic disorders. However, they might cause metabolic syndrome (MetS) in terms of weight gain, dyslipidemia, type 2 diabetes (T2D), and high blood pressure, which are responsible for reduced life expectancy and poor adherence. Importantly, there is clear evidence that early metabolic disturbances can precede weight gain, even if the latter still remains the hallmark of AAPs use. In fact, AAPs interfere profoundly with glucose and lipid homeostasis acting mostly on hypothalamus, liver, pancreatic β-cells, adipose tissue, and skeletal muscle. Their actions on hypothalamic centers via dopamine, serotonin, acetylcholine, and histamine receptors affect neuropeptides and 5'AMP-activated protein kinase (AMPK) activity, thus producing a supraphysiological sympathetic outflow augmenting levels of glucagon and hepatic glucose production. In addition, altered insulin secretion, dyslipidemia, fat deposition in the liver and adipose tissues, and insulin resistance become aggravating factors for MetS. In clinical practice, among AAPs, olanzapine and clozapine are associated with the highest risk of MetS, whereas quetiapine, risperidone, asenapine and amisulpride cause moderate alterations. The new AAPs such as ziprasidone, lurasidone and the partial agonist aripiprazole seem more tolerable on the metabolic profile. However, these aspects must be considered together with the differences among AAPs in terms of their efficacy, where clozapine still remains the most effective. Intriguingly, there seems to be a correlation between AAP's higher clinical efficacy and increase risk of metabolic alterations. Finally, a multidisciplinary approach combining psychoeducation and therapeutic drug monitoring (TDM) is proposed as a first-line strategy to avoid the MetS. In addition, pharmacological treatments are discussed as well.

AVP-786 as a promising treatment option for Alzheimer's Disease including agitation

INTRODUCTION

To date, there is no FDA-approved treatment for agitation in Alzheimer's disease (AD). Medications currently used off-label have modest clinical efficacy and serious side effects.

AREAS COVERED

The authors review the pharmacology, mechanism of action, pharmacokinetics, efficacy, safety and tolerability data of AVP-786, for the treatment of agitation in AD.

EXPERT OPINION

AVP-786, the deuterated form of dextromethorphan/quinidine (AVP-923) which is an approved treatment for Pseudo-Bulbar Affect, emerges as a promising and safe treatment for agitation in AD. Deuteration is an innovative technology that accelerates drug development by conducting faster and less costly clinical trials. No phase II trial was conducted with AVP-786 for the treatment of agitation in AD; the decision to expedite the development of this drug was based on a successful phase II study with AVP-923. Phase III trials with AVP-786 (TRIAD-1 and TRIAD-2) showed mixed findings probably due to the difference in study design. Future phase III studies should use innovative study designs such as the Sequential Parallel Comparison Design to mitigate high placebo response, and the Cohen-Mansfield Agitation Inventory for agitation assessment. They should also include positron emission tomography studies to assess occupancy of various receptors in the brain after AVP-786 is administered.

Forsythoside B attenuates memory impairment and neuroinflammation via inhibition on NF-κB signaling in Alzheimer's disease

Background

Neuroinflammation is a principal element in Alzheimer’s disease (AD) pathogenesis, so anti-inflammation may be a promising therapeutic strategy. Forsythoside B (FTS•B), a phenylethanoid glycoside isolated from Forsythiae fructus, has been reported to exert anti-inflammatory effects. However, no studies have reported whether the anti-inflammatory properties of FTS•B have a neuroprotective effect in AD. In the present study, these effects of FTS•B were investigated using amyloid precursor protein/presenilin 1 (APP/PS1) mice, BV-2 cells, and HT22 cells.

Methods

APP/PS1 mice were administered FTS•B intragastrically for 36 days. Behavioral tests were then carried out to examine cognitive functions, including the Morris water maze, Y maze, and open field experiment. Immunohistochemistry was used to analyze the deposition of amyloid-beta (Aβ), the phosphorylation of tau protein, and the levels of 4-hydroxynonenal, glial fibrillary acidic protein, and ionized calcium-binding adapter molecule 1 in the hippocampus. Proteins that showed marked changes in levels related to neuroinflammation were identified using proteomics and verified using enzyme-linked immunosorbent assay and western blot. BV-2 and HT22 cells were also used to confirm the anti-neuroinflammatory effects of FTS•B.

Results

In APP/PS1 mice, FTS•B counteracted cognitive decline, ameliorated the deposition of Aβ and the phosphorylation of tau protein, and attenuated the activation of microglia and astrocytes in the cortex and hippocampus. FTS•B affected vital signaling, particularly by decreasing the activation of JNK-interacting protein 3/C-Jun NH2-terminal kinase and suppressing WD-repeat and FYVE-domain-containing protein 1/toll-like receptor 3 (WDFY1/TLR3), further suppressing the activation of nuclear factor-κB (NF-κB) signaling. In BV-2 and HT22 cells, FTS•B prevented lipopolysaccharide-induced neuroinflammation and reduced the microglia-mediated neurotoxicity.

Conclusions

FTS•B effectively counteracted cognitive decline by regulating neuroinflammation via NF-κB signaling in APP/PS1 mice, providing preliminary experimental evidence that FTS•B is a promising therapeutic agent in AD treatment.