Current Pharmacotherapy for Alzheimer's Disease

Antidepressant sertraline increases thioflavin-S and Congo red deposition in APPswe/PSEN1dE9 transgenic mice

Introduction: Depression is strongly associated with Alzheimer's disease (AD). Antidepressants are commonly used in patients before and after their diagnosis of AD. To date, the relationship between antidepressants and AD remains unclear. Methods: In our study, we administered sertraline or paroxetine to wild type (WT) and APPswe/PSEN1dE9 (APP/PSEN1) transgenic mouse models for up to 12 months. We quantified the drug concentrations using LC-MS/MS analysis and measured serum serotonin level using an ELISA assay. Additionally, we evaluated the amyloid burdens through thioflavin-S and Congo red stainings, and recognition memory using the novel object recognition test. Results: Our findings revealed that mice treated with paroxetine exhibited a significantly higher level of weight gain compared to the control group and increased mortality in APP/PSEN1 mice. After 12 months of antidepressant treatment, the sertraline level was measured at 289.8 ng/g for cerebellum, while the paroxetine level was 792.9 ng/g for cerebellum. Sertraline significantly increased thioflavin-S and Congo red depositions, along with gliosis, in both isocortex and hippocampus of APP/PSEN1 mice compared to the control group. Both antidepressants also led to a decreased recognition index in APP/PSEN1 mice. Conclusion: These findings suggest a potential role of sertraline in AD pathogenesis, emphasizing the need to reassess the use of these antidepressants in patients with AD.

Biological Evaluation of Anti-Cholinesterase Activity, in Silico Molecular Docking Studies, and DFT Calculations of Green Synthesized Thiadiazolo[3,2-a]pyrimidine Derivatives

A series of [1,3,4] thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives 4(a-n) have been designed and synthesized as inhibitors of acetylcholinesterase (AChE). Synthesizing of thiadiazolo[3,2-a] pyrimidines was carried out in a single step, one-pot reaction using aromatic aldehydes, ethyl acetoacetate and different derivatives of 1,3,4-thiadiazoles (with molar ratio of 1 : 2 : 1, respectively) in conjunction with the catalyst, anhydrous iron(III) chloride by a grinding method under solvent-free conditions at room temperature. The in-vitro studies exhibited good potency for inhibiting AChE comparable with donepezil as the reference drug. The best results were obtained by Ethyl 2-(4-nitroophenyl)-7-methyl-5-(pyridin-3-yl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate 4n with IC50 value of 0.082±0.001 μM which was comparable with AChE inhibitory effects of donepezil (IC50 =0.079 μM).

Tyrosinase Inhibitory Peptides from Enzyme Hydrolyzed Royal Jelly: Production, Separation, Identification and Docking Analysis

Tyrosinase is inextricably related to the development of Alzheimer's disease. The effects of natural tyrosinase inhibitors on human health have attracted widespread attention. This study aimed to isolate and analyze the tyrosinase (TYR) inhibitory peptides in the enzymatic digestion products of royal jelly. We first analyzed optimal process conditions for the enzymatic digestion of royal jelly by single-factor and orthogonal experiments and then used gel filtration chromatography to obtain five fractions (D1~D5) with molecular weights ranging from 600 to 1100 Da. LC-MS/MS was applied to identify the fractions with the highest activity, and the obtained peptides were screened and molecularly docked using AutoDock Vina. The results showed that the optimal enzymatic conditions for tyrosinase inhibition rate were acid protease, enzyme addition 10,000 U/g, initial pH 4, feed-to-liquid ratio 1:4, enzymatic temperature 55 °C, and enzymatic time 4 h. The D4 fraction had the most significant TYR inhibitory activity. The IC₅₀ values of the three new peptides with the strongest TYR inhibitory activity, TIPPPT, IIPFIF, and ILFTLL, were obtained as 7.59 mg/mL, 6.16 mg/mL, and 9.25 mg/mL, respectively. The molecular docking results showed that aromatic and hydrophobic amino acids were more favorable to occupy the catalytic center of TYR. In conclusion, the new peptide extracted from royal jelly has the potential to be used as a natural TYR inhibitory peptide in food products with health-promoting properties.

Design, synthesis, and evaluation of hydrazones as dual inhibitors of ryanodine receptors and acetylcholinesterases for Alzheimer's disease

Alzheimer's disease (AD) implicates neuronal loss, plaque and neurofibrillary tangle formation, and disturbed neuronal Ca²⁺ homeostasis, which leads to severe dementia, memory loss, as well as thinking and behavioral perturbations that could ultimately lead to death. Calcium dysregulation and low acetylcholine levels are two main mechanisms implicated in Alzheimer's disease progression. Simultaneous inhibition of calcium oscillations (store overload-induced Ca²⁺ release [SOICR]) and acetylcholinesterase (AChE) by a single molecule may bring a new breath of hope for AD treatment. Here, we described some dantrolene derivatives as dual inhibitors of the ryanodine receptor and AChE. Two series of acylhydrazone/sulfonylhydrazone derivatives with aromaticgroup were designed and synthesized. In this study, the target compounds were evaluated for their ability to inhibit SOICR and AChE in vitro, using dantrolene and donepezil as positive controls. Compound 22a exhibited excellent and balanced inhibitory potency against SOICR (inhibition (%) = 90.1, IC₅₀ = 0.162 μM) and AChE (inhibition (%) = 93.5, IC₅₀ = 0.372 μM). Docking simulations showed that several preferred compounds could bind to the active sites of both the proteins, further validating the rationality of the design strategy. Potential therapeutic effects in AD were evaluated using the Barnes maze and Morris water maze tests, which demonstrated that compound 22a significantly improved memory and cognitive behavior in AD model mice. Moreover, it was also found that compound 22a could enhance synaptic strength by measuring hippocampal long-term potentiation (LTP) in brain slices. These results suggested that the introduction of a sulfonyl-hydrazone scaffold and aromatic substitution to dantrolene derivatives provided a useful template for the development of potential chemical entities against AD.

An ongoing journey of chalcone analogues as single and multi-target ligands in the field of Alzheimer's disease: A review with structural aspects

Alzheimer's disease (AD) is a chronic and irreversible neurodegenerative disorder with progressive dementia and cognitive impairment. AD poses severe health challenge in elderly people and become one of the leading causes of death worldwide. It possesses complex pathophysiology with several hypotheses (cholinergic hypothesis, amyloid hypothesis, tau hypothesis, oxidative stress, mitochondrial dysfunction etc.). Several attempts have been made for the management of multifactorial AD. Acetylcholinesterase is the only target has been widely explored in the management of AD to the date. The current review set forth the chalcone based natural, semi-synthetic and synthetic compounds in the search of potential anti-Alzheimer's agents. The main highlights of current review emphasizes on chalcone target different enzymes and pathways like Acetylcholinesterase, β-secretase (BACE1), tau proteins, MAO, free radicals, Advanced glycation end Products (AGEs) etc. and their structure activity relationships contributing in the inhibition of above mentioned various targets of AD.

Circadian dysfunction and Alzheimer's disease - An updated review

Alzheimer's disease (AD) is considered to be the most typical form of dementia that provokes irreversible cognitive impairment. Along with cognitive impairment, circadian rhythm dysfunction is a fundamental factor in aggravating AD. A link among circadian rhythms, sleep, and AD has been well-documented. The etiopathogenesis of circadian system disruptions and AD serves some general characteristics that also open up the possibility of viewing them as a mutually reliant path. In this review, we have focused on different factors that are related to circadian rhythm dysfunction. The various pathogenic factors, such as amyloid-beta, neurofibrillary tangles, oxidative stress, neuroinflammation, and circadian rhythm dysfunction may all contribute to AD. In this review, we also tried to focus on melatonin which is produced from the pineal gland and can be used to treat circadian dysfunction in AD. Aside from amyloid beta, tau pathology may have a notable influence on sleep. Conclusively, the center of this review is primarily based on the principal mechanistic complexities associated with circadian rhythm disruption, sleep deprivation, and AD, and it also emphasizes the potential therapeutic strategies to treat and prevent the progression of AD.

Mechanistic Insights, Treatment Paradigms, and Clinical Progress in Neurological Disorders: Current and Future Prospects

Neurodegenerative diseases (NDs) are a major cause of disability and are related to brain development. The neurological signs of brain lesions can vary from mild clinical shortfalls to more delicate and severe neurological/behavioral symptoms and learning disabilities, which are progressive. In this paper, we have tried to summarize a collective view of various NDs and their possible therapeutic outcomes. These diseases often occur as a consequence of the misfolding of proteins post-translation, as well as the dysfunctional trafficking of proteins. In the treatment of neurological disorders, a challenging hurdle to cross regarding drug delivery is the blood-brain barrier (BBB). The BBB plays a unique role in maintaining the homeostasis of the central nervous system (CNS) by exchanging components between the circulations and shielding the brain from neurotoxic pathogens and detrimental compounds. Here, we outline the current knowledge about BBB deterioration in the evolving brain, its origin, and therapeutic interventions. Additionally, we summarize the physiological scenarios of the BBB and its role in various cerebrovascular diseases. Overall, this information provides a detailed account of BBB functioning and the development of relevant treatments for neurological disorders. This paper will definitely help readers working in the field of neurological scientific communities.

Sex differences in hippocampal β-amyloid accumulation in the triple-transgenic mouse model of Alzheimer's disease and the potential role of local estrogens

Introduction

Epidemiological studies show that women have a higher prevalence of Alzheimer's disease (AD) than men. Peripheral estrogen reduction during aging in women is proposed to play a key role in this sex-associated prevalence, however, the underlying mechanism remains elusive. We previously found that transcription factor early growth response-1 (EGR1) significantly regulates cholinergic function. EGR1 stimulates acetylcholinesterase (AChE) gene expression and is involved in AD pathogenesis. We aimed to investigate whether the triple-transgenic AD (3xTg-AD) mice harboring PS1 ^M146V , APP ^Swe , and Tau ^P301L show sex differences in β-amyloid (Aβ) and hyperphosphorylated tau (p-Tau), the two primary AD hallmarks, and how local 17β-estradiol (E2) may regulate the expression of EGR1 and AChE.

Methods

We first sacrificed male and female 3xTg-AD mice at 3-4, 7-8, and 11-12 months and measured the levels of Aβ, p-Tau, EGR1, and AChE in the hippocampal complex. Second, we infected SH-SY5Y cells with lentivirus containing the amyloid precursor protein construct C99, cultured with or without E2 administration we measured the levels of extracellular Aβ and intracellular EGR1 and AChE.

Results

Female 3xTg-AD mice had higher levels of Aβ compared to males, while no p-Tau was found in either group. In SH-SY5Y cells infected with lentivirus containing the amyloid precursor protein construct C99, we observed significantly increased extracellular Aβ and decreased expression of intracellular EGR1 and AChE. By adding E2 to the culture medium, extracellular Aβ(l-42) was significantly decreased while intracellular EGR1 and AChE expression were elevated.

Discussion

This data shows that the 3xTg-AD mouse model can be useful for studying the human sex differences of AD, but only in regards to Ap. Furthermore, in vitro data shows local E2 may be protective for EGR1 and cholinergic functions in AD while suppressing soluble Aβ(1-42) levels. Altogether, this study provides further in vivo and in vitro data supporting the human epidemiological data indicating a higher prevalence of AD in women is related to changes in brain estrogen levels.

Metformin inhibits cardiometabolic syndrome associated cognitive deficits in high fat diet rats

Objectives

Glucose intolerance and insulin resistance are hallmarks of metabolic syndrome and lead to Alzheimer's disease (AD). The purpose of this study is to elucidate the neuroprotective effect of metformin through insulin regulation with cardiometabolic and neurotransmitter metabolic enzyme regulation in high-fat, high-sucrose diet and streptozotocin (HFHS-STZ)-induced rats.

Methods

Male Wistar rats were treated with metformin (180 mg/kg and 360 mg/kg). STZ (35 mg/kg i.p.) injection was performed on the 14th day of 42 days of HFHS diet treatment. Brain neurotransmitter metabolic enzymes (acetylcholinesterase and monoamine oxidase) were determined along with sodium-potassium ATPase (Na+K+-ATPase). Plasma lipids and homeostasis model assessment of insulin resistance (HOMA-IR) was performed. Mean arterial blood pressure, heart rate and electrocardiogram (QT, QTc and RR intervals) were analysed with PowerLab.

Results

Metformin treatment significantly (p < 0.001) reduced the HOMA-IR index and decreased neurotransmitter metabolic enzymes such as AChE and MAO (p < 0.01 and p < 0.05). The lipid profile was significantly (p < 0.001) controlled with cardiometabolic functions.

Conclusions

Our investigation revealed that metformin has a remarkable role in regulating brain insulin, vascular system with monoaminergic metabolic enzymes and enhancing synaptic plasticity. Metformin may be a selective early therapeutic agent in metabolic syndrome associated with cognitive decline.

Protein and Gene Delivery Systems for Neurodegenerative Disorders: Where Do We Stand Today?

It has been estimated that every year, millions of people are affected by neurodegenerative disorders, which complicate their lives and their caregivers' lives. To date, there has not been an approved pharmacological approach to provide the complete treatment of neurodegenerative disorders. The only available drugs may only relieve the symptoms or slow down the progression of the disease. The absence of any treatment is quite rational given that neurodegeneration occurs by the progressive loss of the function or structure of the nerve cells of the brain or the peripheral nervous system, which eventually leads to their death either by apoptosis or necrotic cell death. According to a recent study, even though adult brain cells are injured, they can revert to an embryonic state, which may help to restore their function. These interesting findings might open a new path for the development of more efficient therapeutic strategies to combat devastating neurodegenerative disorders. Gene and protein therapies have emerged as a rapidly growing field for various disorders, especially neurodegenerative diseases. Despite these promising therapies, the complete treatment of neurodegenerative disorders has not yet been achieved. Therefore, the aim of this review is to address the most up-to-date data for neurodegenerative diseases, but most importantly, to summarize the available delivery systems incorporating proteins, peptides, and genes that can potentially target such diseases and pass into the blood-brain barrier. The authors highlight the advancements, at present, on delivery based on the carrier, i.e., lipid, polymeric, and inorganic, as well as the recent studies on radiopharmaceutical theranostics.

Design, synthesis, and structure-activity relationship of caffeine-based triazoles as dual AChE and BACE-1 inhibitors

Natural products have significantly contributed to drug discovery for neurodegenerative diseases. Caffeine is one of the well-known central nervous system(CNS)-active natural products. Besides its CNS stimulant properties, it is a mild inhibitor of acetylcholinesterase (AChE) and possesses memory-enhancing properties. The present work aimed to improve the AChE inhibition activity of the caffeine. The rationally designed caffeine-based triazoles were synthesized and evaluated in vitro for cholinesterase and β-site amyloid precursor protein cleaving enzyme-1 (BACE-1) inhibitory activities. The attachment of triazole to the caffeine enhances its AChE inhibition activity from half-maximal inhibitory concentration (IC₅₀ ) of 129 µM to 0.49 µM (derivative, 6l). The caffeine core interacts with the peripheral anionic site, whereas the benzyl triazole occupies the catalytic anionic site located at the bottom of the active site gorge. The structure-activity relationship revealed that the four-atom ester linker is superior to shorter linkers for connecting the caffeine core to the triazole. The 2,6-difluorobenzyl triazole-linked caffeine derivative, 6d, exhibits dual inhibition of AChE and BACE-1 with IC₅₀ values of 1.43 and 10.9 µM, respectively. The derivative 6d inhibits AChE via a mixed-type mode with an inhibition rate constant (K_i ) value of 2.35 μM, which was corroborated by docking studies. The triazole 6d has an acceptable stability profile in human liver microsomes (t_1/2  = 54 min) and was found to possess CNS permeability when evaluated using the parallel artificial membrane permeability blood-brain barrier assay. The results presented herein warrant investigating caffeine-based triazoles in preclinical models of Alzheimer's disease.

Ameliorative Effects by Hexagonal Boron Nitride Nanoparticles against Beta Amyloid Induced Neurotoxicity

Alzheimer’s disease (AD) is considered as the most common neurodegenerative disease. Extracellular amyloid beta (Aβ) deposition is a hallmark of AD. The options based on degradation and clearance of Aβ are preferred as promising therapeutic strategies for AD. Interestingly, recent findings indicate that boron nanoparticles not only act as a carrier but also play key roles in mediating biological effects. In the present study, the aim was to investigate the effects of different concentrations (0−500 mg/L) of hexagonal boron nitride nanoparticles (hBN-NPs) against neurotoxicity by beta amyloid (Aβ1-42) in differentiated human SH-SY5Y neuroblastoma cell cultures for the first time. The synthesized hBN-NPs were characterized by X-ray diffraction (XRD) measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Aβ1-42-induced neurotoxicity and therapeutic potential by hBN-NPs were assessed on differentiated SH-SY5Y cells using MTT and LDH release assays. Levels of total antioxidant capacity (TAC) and total oxidant status (TOS), expression levels of genes associated with AD and cellular morphologies were examined. The exposure to Aβ1-42 significantly decreased the rates of viable cells which was accompanied by elevated TOS level. Aβ1-42 induced both apoptotic and necrotic cell death. Aβ exposure led to significant increases in expression levels of APOE, BACE 1, EGFR, NCTSN and TNF-α genes and significant decreases in expression levels of ADAM 10, APH1A, BDNF, PSEN1 and PSENEN genes (p < 0.05). All the Aβ1-42-induced neurotoxic insults were inhibited by the applications with hBN-NPs. hBN-NPs also suppressed the remarkable elevation in the signal for Aβ following exposure to Aβ1-42 for 48 h. Our results indicated that hBN-NPs could significantly prevent the neurotoxic damages by Aβ. Thus, hBN-NPs could be a novel and promising anti-AD agent for effective drug development, bio-nano imaging or drug delivery strategies.

Rational Design of a Theranostic Agent Triggered by Endogenous Nitric Oxide in a Cellular Model of Alzheimer's Disease

Oxidative damage caused by upregulated nitric oxide (NO) plays an important role in the pathogenesis of Alzheimer's disease (AD). Currently, stimulus-triggered theranostic agents have received much attention due to benefits on disease imaging and targeted therapeutic effects. However, the development of a theranostic agent triggered by NO for AD remains unexplored. Herein, through the mechanism analysis of the reaction between a fluorophore of 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) and NO, which we occasionally found and thereafter structure optimization of DPAC, a theranostic agent DPAC-(peg)₄-memantine was fabricated. In an AD cellular model, DPAC-(peg)₄-memantine exhibits NO sensing ability for AD imaging. Meanwhile, DPAC-(peg)₄-memantine shows improved therapeutic by targeted drug release triggered by NO and sustained therapeutic effects owing to the synergetic antioxidative abilities via the anti-AD drug and NO scavenging. This work provides an unprecedented avenue for the studies on not only AD but also other diseases with NO upregulation.

The Comparative Efficacy of Multiple Acupuncture for Alzheimer's Disease: A Bayesian Network Meta-Analysis

Background

Alzheimer's disease (AD) is a progressive neurodegenerative disease. Numerous cases have illustrated that the acupuncture method could improve AD patients' cognitive function and daily living ability. However, the optimal acupuncture treatments remain controversial. Therefore, we aimed to conduct a systematic review to compare the efficacy of multiple acupuncture therapies for AD and identify the optimal acupuncture intervention for delaying AD progression.

Methods

To select potentially concerned randomized controlled trials (RCTs), we searched four English databases, four Chinese databases, and additional sources from 1 May 2021. Two independent reviewers conducted study screening, data extraction, and methodological quality assessment. The primary outcome was global cognitive function improvement. Pairwise and Bayesian network meta-analyses were performed using STATA v15.0 and ADDIS v1.16.8. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool was used to assess the quality of evidence.

Results

This study included 34 RCTs with 2,071 participants. Regarding global cognitive function improvement, the pairwise meta-analysis confirmed that electronic acupuncture (EA) plus conventional medicine (CM) and manual acupuncture (MA) plus CM were statistically significantly different from CM, and EA plus CM was ranked as the best combination in the network meta-analysis. In terms of response rate, MA outperformed CM statistically significantly; warm acupuncture (WA) was ranked as the best in the network meta-analysis. Regarding activity of daily living improvement, EA plus CM, MA plus CM, and fire acupuncture plus CM, MA, and scalp acupuncture were statistically significantly different from CM, and EA plus CM was ranked as the best combination in the network meta-analysis. However, the evidences were ranked as low to critically low.

Conclusions

Acupuncture, as a monotherapy or an adjuvant therapy, may have a beneficial effect on efficacy for AD. EA plus CM may be the optimal acupuncture therapy for AD and should be administered to AD patients. It may aid and support patient, operative, and societal decision-making. Due to the dearth of high-quality evidence, additional high-quality studies should be conducted to ensure these findings in the future. This study is registered with PROSPERO (CRD42021252305).

Synthesis, characterization, and biological evaluation of some novel Schiff bases as potential metabolic enzyme inhibitors

In this study, a series of novel Schiff base derivatives containing a pyrazolone ring (2a-e) were designed, successfully synthesized for the first time, and characterized by elemental analysis and some spectroscopic methods. These compounds were tested for their inhibitory activities on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and the human carbonic anhydrase isoenzymes I and II (hCA I and II). All synthesized molecules indicated significant inhibition effects with IC₅₀ values ranging from 14.15 to 107.62 nM against these enzymes. Compound 2d showed the most potent inhibitory activity among the tested molecules toward AChE and BChE (IC₅₀  = 15.07 and 14.15 nM) compared to the standard drug neostigmine. We determined that the IC₅₀ values of the tested molecules ranged between 16.86 and 57.96 nM for hCA I and 15.24-46.21 nM for hCA II. As a consequence, we may say that some of the Schiff base derivatives may be used as potential drug candidates in later studies.

Antiradical Activity of Dopamine, L-DOPA, Adrenaline, and Noradrenaline in Water/Methanol and in Liposomal Systems

Catecholamines play a crucial role in signal transduction and are also expected to act as endogeneous antioxidants, but the mechanism of their antioxidant action is not fully understood. Here, we describe the impact of pH on the kinetics of reaction of four catecholamines (L-DOPA, dopamine, adrenaline, and noradrenaline) with model 2,2-diphenyl-1-picrylhydrazyl radical (dpph^•) in methanol/water. The increase in pH from 5.5 to 7.4 is followed by a 2 order of magnitude increase in the rate constant, e.g., for dopamine (DA) k^pH5.5 = 1,200 M^–1 s^–1 versus k^pH7.4 = 170,000 M^–1 s^–1, and such rate acceleration is attributed to a fast electron transfer from the DA anion to dpph^•. We also proved that at pH 7.0 DA breaks the peroxidation chain of methyl linoleate in liposomes assembled from neutral and negatively charged phospholipids. In contrast to no inhibitory effect during peroxidation in non-ionic emulsions, in bilayers one molecule of DA traps approximately four peroxyl radicals, with a rate constant k_inh >10³ M^–1 s^–1. Our results from a homogeneous system and bilayers prove that catecholamines act as effective, radical trapping antioxidants with activity depending on the ionization status of the catechol moiety, as well as microenvironment: organization of the lipid system (emulsions vs bilayers) and interactions of catecholamines with the biomembrane.

Altered Homotopic Functional Connectivity Within White Matter in the Early Stages of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with memory loss and cognitive impairment. The white matter (WM) BOLD signal has recently been shown to provide an important role in understanding the intrinsic cerebral activity. Although the altered homotopic functional connectivity within gray matter (GM-HFC) has been examined in AD, the abnormal HFC to WM remains unknown. The present study sought to identify changes in the WM-HFC and anatomic characteristics by combining functional magnetic resonance imaging with diffusion tensor imaging (DTI). Resting-state and DTI magnetic resonance images were collected from the OASIS-3 dataset and consisted of 53 mild cognitive impairment (MCI) patients, 90 very MCI (VMCI), and 100 normal cognitive (NC) subjects. Voxel-mirrored HFC was adopted to examine whether WM-HFC was disrupted in VMCI and MCI participants. Moreover, the DTI technique was used to investigate whether specific alterations of WM-HFC were associated with anatomic characteristics. Support vector machine analyses were used to identify the MCI and VMCI participants using the abnormal WM-HFC as the features. Compared with NC, MCI, and VMCI participants showed significantly decreased GM-HFC in the middle occipital gyrus and inferior parietal gyrus and decreased WM-HFC in the bilateral middle occipital and parietal lobe-WM. In addition, specific WM-functional network alteration for the bilateral sub-lobar-WM was found in MCI subjects. MCI subjects showed abnormal anatomic characteristics for bilateral sub-lobar and parietal lobe-WM. Results of GM-HFC mainly showed common neuroimaging features for VMCI and MCI subjects, whereas analysis of WM-HFC showed specific clinical neuromarkers and effectively compensated for the lack of GM-HFC to distinguish NC, VMCI, and MCI subjects.

Understanding the Modulatory Effects of Cannabidiol on Alzheimer's Disease

Alzheimer’s disease (AD), the most common neurodegenerative disease, is characterized by progressive cognitive impairment. The deposition of amyloid beta (Aβ) and hyperphosphorylated tau is considered the hallmark of AD pathology. Many therapeutic approaches such as Food and Drug Administration-approved cholinesterase inhibitors and N–methyl–D–aspartate receptor antagonists have been used to intervene in AD pathology. However, current therapies only provide limited symptomatic relief and are ineffective in preventing AD progression. Cannabidiol (CBD), a phytocannabinoid devoid of psychoactive responses, provides neuroprotective effects through both cannabinoid and noncannabinoid receptors. Recent studies using an AD mouse model have suggested that CBD can reverse cognitive deficits along with Aβ-induced neuroinflammatory, oxidative responses, and neuronal death. Furthermore, CBD can reduce the accumulation of Aβ and hyperphosphorylation of tau, suggesting the possibility of delaying AD progression. Particularly, the noncannabinoid receptor, peroxisome proliferator-activated receptor gamma, has been suggested to be involved in multiple functions of CBD. Therefore, understanding the underlying mechanisms of CBD is necessary for intervening in AD pathology in depth and for the translation of preclinical studies into clinical settings. In this review, we summarize recent studies on the effect of CBD in AD and suggest problems to be overcome for the therapeutic use of CBD.

Synthesis, Biological Evaluation, and In Silico Studies of New Acetylcholinesterase Inhibitors Based on Quinoxaline Scaffold

A quinoxaline scaffold exhibits various bioactivities in pharmacotherapeutic interests. In this research, twelve quinoxaline derivatives were synthesized and evaluated as new acetylcholinesterase inhibitors. We found all compounds showed potent inhibitory activity against acetylcholinesterase (AChE) with IC50 values of 0.077 to 50.080 µM, along with promising predicted drug-likeness and blood-brain barrier (BBB) permeation. In addition, potent butyrylcholinesterase (BChE) inhibitory activity with IC50 values of 14.91 to 60.95 µM was observed in some compounds. Enzyme kinetic study revealed the most potent compound (6c) as a mixed-type AChE inhibitor. No cytotoxicity from the quinoxaline derivatives was noticed in the human neuroblastoma cell line (SHSY5Y). In silico study suggested the compounds preferred the peripheral anionic site (PAS) to the catalytic anionic site (CAS), which was different from AChE inhibitors (tacrine and galanthamine). We had proposed the molecular design guided for quinoxaline derivatives targeting the PAS site. Therefore, the quinoxaline derivatives could offer the lead for the newly developed candidate as potential acetylcholinesterase inhibitors.

Anti-Alzheimer chemical constituents of Morus macroura Miq.: chemical profiling, in silico and in vitro investigations

Herein, we investigated both fruits and leaves of Morus macroura Miq. as a potential source of bioactive compounds against Alzheimer's disease (AD). LC-HRMS-assisted chemical profiling of its extracts showed that they are a rich source of diverse phytochemicals. Among the 29 identified compounds in both the fruit and leaf extracts, moracin D, chrysin, resveratrol, and ferulic acid were predicted to pass the human blood-brain barrier (BBB), and hence, reach their therapeutic targets in the brain. Subsequently, these compounds were subjected to a comprehensive pharmacophore-based screening for their protein targets relevant to AD using two independent software programs (i.e. Swiss Target Prediction and PharmMapper). The results of this initial virtual screening were further refined by a number of docking and molecular dynamic simulation experiments to suggest a number of crucial AD-related proteins (e.g. acetylcholine esterase, β-secretase, and monoamine oxidase) as potential targets for these compounds. Finally, in vitro testing was performed to validate the in silico investigation's results, where chrysin, resveratrol, and ferulic acid were found to inhibit the predicted AD-related enzymes with IC₅₀ values comparable with those of the reference inhibitors. Additionally, they were able to inhibit the aggregation of amyloid-beta, one of the hallmarks in AD pathogenesis, and to exhibit considerable antioxidant capacity. Our results highlighted Morus macroura compounds as future anti-Alzheimer chemical leads.

Neuroprotective effects of NDEELNK from sea cucumber ovum against scopolamine-induced PC12 cell damage through enhancing energy metabolism and upregulation of the PKA/BDNF/NGF signaling pathway

The aim of the study was to evaluate the neuroprotective function of sea cucumber ovum peptide-derived NDEELNK and explore the underlying molecular mechanisms. NDEELNK exerted the neuroprotective effect by improving the acetylcholine (ACh) level and reducing the acetylcholinesterase (AChE) activity in PC12 cells. By molecular docking, we confirmed that the NDEELNK backbone and AChE interacted through hydrophobic and hydrogen bonds in contact with the amino acid residues of the cavity wall. NDEELNK increased superoxide dismutase (SOD) activity and decreased reactive oxygen species (ROS) production, thereby reducing mitochondrial dysfunction and enhancing energy metabolism. Our results demonstrated that NDEELNK supplementation alleviated scopolamine-induced PC12 cell damage by improving the cholinergic system, increasing energy metabolism and upregulating the expression of phosphorylated protein kinase A (p-PKA), brain-derived neurotrophic factor (BNDF) and nerve growth factor (NGF) signaling proteins in in vitro experiments. These results demonstrated that the sea cucumber ovum peptide-derived NDEELNK might play a protective role in PC12 cells.

Acetylcholinesterase inhibitory activity of extract and fractions from the root of Rauvolfia serpentina(L.) Bth.ex Kurz

OBJECTIVES

Alzheimer's disease (AD) is a degenerative brain disease characterized by confusion, behavior changes, decline in memory and cognitive skills. One of the strategies in the treatment of AD is to use acetylcholinesterase (AChE) inhibitors. The current study aims to determine the AChE inhibitory activities of the extract and fractions of the root of Rauvolfia serpentina.

METHODS

Extraction was carried out by maceration method using ethanol, followed by liquid-liquid partition using n-hexane, ethyl acetate and n-butanol. Further fractionation was conducted by using vacuum liquid chromatography (VLC). The AChE inhibitory assays were performed by using Ellmann's method. Phytochemical screening was carried out by TLC method.

RESULTS

The ethanolic extract of R. serpentina showed inhibition against AChE enzyme with an IC₅₀ value of 7.46 μg/mL. The extract and fractions showed higher inhibition against butyrylcholinesterase (BChE) compared to AChE. Amongst three fractions obtained, the n-butanol fraction showed the strongest inhibition with an IC₅₀ value of 5.99 μg/mL against AChE. VLC fractionation of the n-butanol fraction yielded 13 subfractions (VLC 1-VLC 13). Four out of 13 subfractions gave more than 80% inhibition against AChE, namely subfractions 4-7, with IC₅₀ values ranging from 4.87 to 47.22 μg/mL. The phytochemical screening of these subfractions suggested the presence of alkaloids.

CONCLUSIONS

The ethanolic extract, as well as fractions of R. serpentina root, are potential for AChE inhibitor. The alkaloid compound may be responsible for this activity.

Current Quest in Natural Bioactive Compounds for Alzheimer's Disease: Multi-Targeted-Designed-Ligand Based Approach with Preclinical and Clinical Based Evidence

Alzheimer's disease is a common and most chronic neurological disorder (NDs) associated with cognitive dysfunction. Pathologically, Alzheimer's disease (AD) is characterized by the presence of β-amyloid (Aβ) plaques, hyper-phosphorylated tau proteins, and neurofibrillary tangles, however, persistence oxidative-nitrative stress, endoplasmic reticulum stress, mitochondrial dysfunction, inflammatory cytokines, pro-apoptotic proteins along with altered neurotransmitters level are common etiological attributes in its pathogenesis. Rivastigmine, memantine, galantamine, and donepezil are FDA approved drugs for symptomatic management of AD, whereas tacrine has been withdrawn because of hepatotoxic profile. These approved drugs only exert symptomatic relief and exhibit poor patient compliance. In the current scenario, the number of published evidence shows the neuroprotective potential of naturally occurring bioactive molecules via their antioxidant, anti-inflammatory, antiapoptotic and neurotransmitter modulatory properties. Despite their potent therapeutic implications, concerns have arisen in context to their efficacy and probable clinical outcome. Thus, to overcome these glitches, many heterocyclic and cyclic hydrocarbon compounds inspired by natural sources have been synthesized and showed improved therapeutic activity. Computational studies (molecular docking) have been used to predict the binding affinity of these natural bioactive as well as synthetic compounds derived from natural sources for the acetylcholine esterase, α/β secretase Nuclear Factor kappa- light-chain-enhancer of activated B cells (NF-kB), Nuclear factor erythroid 2-related factor 2(Nrf2) and other neurological targets. Thus, in this review, we have discussed the molecular etiology of AD, focused on the pharmacotherapeutics of natural products, chemical and pharmacological aspects and multi-targeted designed ligands (MTDLs) of synthetic and semisynthetic molecules derived from the natural sources along with some important on-going clinical trials.

The effect of intracerebroventricular amyloid beta 1-42 application on cognitive functions in aged rats supplemented with taurine and the change of peroxisomal proteins in this process

OBJECTIVE

The aim of our study is to investigate the change of peroxisomal proteins in the neurodegenerative and oxidative process caused by the neurotoxicity of Aβ 1-42 in aged rats supplemented with taurine and to show the possible positive effects of taurine in this process.

METHODS

30 Wistar albino rats were randomly divided into 5 groups as control, sham, Aβ 1-42, taurine, and Aβ 1-42+taurine. Taurine administration continued for 6 weeks (1000 mg/kg/day with drinking water). Stereotaxic surgery was applied to all groups (intracerebroventricular per lateral ventricle needle only or 5 μl, PBS, or Aβ 1-42). Spatial learning and memory performances of the animals were evaluated with Morris water maze and elevated plus maze. The levels of MDA and GSH were measured as oxidative stress parameters in the cerebral cortex and hippocampus. Expressions of CAT, PEX14, PMP70 of peroxisomal membrane proteins were indicated by Western blot analysis.

RESULTS

Our results showed that injection of Aβ 1-42 decreased the spatial learning and memory performance, cortex CAT and hippocampus PEX14, PMP70 and GSH levels, and increased cortex and hippocampus MDA levels (p < 0.05). Although the administration of taurine partially ameliorated the adverse effects of Aβ 1-42 injection, a significant difference was found only at the hippocampus GSH levels (p < 0.05). Also, taurine caused anxiety at this dose (p < 0.05).

DISCUSSION

In conclusion, decreased peroxisomal proteins and antioxidant capacity in neurodegenerative and oxidative processes induced by intracerebroventricular Aβ 1-42 injection showed that peroxisomes may play a role in this process and taurine supplementation may have positive effects especially in increasing antioxidant capacity.

Targeting receptor-ligand chemistry for drug delivery across blood-brain barrier in brain diseases

The blood-brain barrier (BBB) is composed of a layer of endothelial cells that is interspersed with a series of tight junctions and characterized by the absence of fenestrations. The permeability of this barrier is controlled by junctions such as tight junctions and adherent junctions as well as several cells such as astrocytes, pericytes, vascular endothelial cells, neurons, microglia, and efflux transporters with relatively enhanced expression. It plays a major role in maintaining homeostasis in the brain and exerts a protective regulatory control on the influx and efflux of molecules. However, it proves to be a challenge for drug delivery strategies that target brain diseases like Dementia, Parkinson's Disease, Alzheimer's Disease, Brain Cancer or Stroke, Huntington's Disease, Lou Gehrig's Disease, etc. Conventional modes of drug delivery are invasive and have been known to contribute to a "leaky BBB", recent studies have highlighted the efficiency and relative safety of receptor-mediated drug delivery. Several receptors are exhibited on the BBB, and actively participate in nutrient uptake, and recognize specific ligands that modulate the process of endocytosis. The strategy employed in receptor-mediated drug delivery exploits this process of "tricking" the receptors into internalizing ligands that are conjugated to carrier systems like liposomes, nanoparticles, monoclonal antibodies, enzymes etc. These in turn are modified with drug molecules, therefore leading to delivery to desired target cells in brain tissue. This review comprehensively explores each of those receptors that can be modified to serve such purposes as well as the currently employed strategies that have led to increased cellular uptake and transport efficiency.

Fucosterol from Sargassum horridum as an amyloid-beta (Aβ1-42) aggregation inhibitor: in vitro and in silico studies

The number of patients diagnosed with Alzheimer's disease (AD) increases each year, and there are currently few treatment strategies to decrease the symptoms of AD; furthermore, these strategies are not sufficient to reduce memory loss in AD patients. In this work, in vitro and in silico studies were performed to evaluate the effects of fucosterol, which was extracted from an algal source and characterized by liquid chromatography-mass spectra (LC-MS), as an inhibitor of Aβ1-42 aggregation. Experimental studies, including protein gel electrophoresis, atomic force microscopy and fluorescence studies with thioflavin T (ThT), highlighted that fucosterol can decrease oligomer formation more than galantamine, which was used as a positive control. Docking and molecular dynamics simulations coupled with an MMGBSA approach showed that fucosterol is capable of recognizing the hydrophobic regions of monomeric Aβ1-42, suggesting that fucosterol could affect amyloid-beta (Aβ1-42) aggregation by preventing the formation of oligomers, preventing the development of AD.Communicated by Ramaswamy H. Sarma.

20(S)-protopanaxadiol and oleanolic acid ameliorate cognitive deficits in APP/PS1 transgenic mice by enhancing hippocampal neurogenesis

Background

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders. Enhancing hippocampal neurogenesis by promoting proliferation and differentiation of neural stem cells (NSCs) is a promising therapeutic strategy for AD. 20(S)-protopanaxadiol (PPD) and oleanolic acid (OA) are small, bioactive compounds found in ginseng that can promote NSC proliferation and neural differentiation in vitro. However, it is currently unknown whether PPD or OA can attenuate cognitive deficits by enhancing hippocampal neurogenesis in vivo in a transgenic APP/PS1 AD mouse model. Here, we administered PPD or OA to APP/PS1 mice and monitored the effects on cognition and hippocampal neurogenesis.

Methods

We used the Morris water maze, Y maze, and open field tests to compare the cognitive capacities of treated and untreated APP/PS1 mice. We investigated hippocampal neurogenesis using Nissl staining and BrdU/NeuN double labeling. NSC proliferation was quantified by Sox2 labeling of the hippocampal dentate gyrus. We used western blotting to determine the effects of PPD and OA on Wnt/GSK3β/β-catenin pathway activation in the hippocampus.

Results

Both PPD and OA significantly ameliorated the cognitive impairments observed in untreated APP/PS1 mice. Furthermore, PPD and OA significantly promoted hippocampal neurogenesis and NSC proliferation. At the mechanistic level, PPD and OA treatments resulted in Wnt/GSK-3β/β-catenin pathway activation in the hippocampus.

Conclusion

PPD and OA ameliorate cognitive deficits in APP/PS1 mice by enhancing hippocampal neurogenesis, achieved by stimulating the Wnt/GSK-3β/β-catenin pathway. As such, PPD and OA are promising novel therapeutic agents for the treatment of AD and other neurodegenerative diseases.

A new acetylcholinesterase allosteric site responsible for binding voluminous negatively charged molecules - the role in the mechanism of AChE inhibition

Acetylcholinesterase (AChE) inhibitors are important in the treatment of neurodegenerative diseases. Two inhibitors, 12-tungstosilicic acid (WSiA) and 12-tungstophosphoric acid (WPA), which have polyoxometalate (POM) type structure, have been shown to inhibit AChE activity in nM concentration. Circular dichroism and tryptophan fluorescence spectroscopy demonstrated that the AChE inhibition was not accompanied by significant changes in the secondary structure of the enzyme. The molecular docking approach has revealed a new allosteric binding site, termed β-allosteric site (β-AS), which is considered responsible for the inhibition of AChE by POMs. To the best of our knowledge, this is the first study reporting a new allosteric site that is considered responsible for AChE inhibition by voluminous and negatively charged molecules such as POMs. The selected POMs were further subjected to genotoxicity testing using human peripheral blood cells as a model system. It was shown that WSiA and WPA induced a mild cytostatic but not genotoxic effects in human lymphocytes, which indicates their potential to be used as medicinal drugs. The identification of non-toxic compounds capable of binding to an allosteric site that so far has not been considered responsible for enzyme inhibition could be fundamental for the development of new drug design strategies and the discovery of more efficient AChE modulators.

Therapeutic potential of selanyl amide derivatives in the in vitro anticholinesterase activity and in in vivo antiamnesic action

The present study evaluated the in vitro acetylcholinesterase (AChE) inhibitor activity of two new selanyl amide derivatives in cerebral structures of mice. Our results demonstrated that N-(2-(3-(phenylselanyl)propoxy)phenyl)furan-2-carboxamide (1) and N-(2-(3-(phenylselanyl)propoxy)phenyl)thiophene-2-carboxamide (2) inhibited the in vitro AChE activity in mice. Another objective was to assess the effect of the best AChE inhibitor in an amnesic model induced by scopolamine (SCO) in male Swiss mice. The involvement of AChE activity and lipid peroxidation in the cerebral structures was investigated. Our results showed that compound 1 (10 mg/kg, intragastrically) attenuated the latency to find the escape box and the number of holes visited in the Barnes maze task, without altering the locomotor and exploratory activities in an open-field test. Compound 1 protected against increasing in lipid peroxidation levels and AChE activity caused by SCO in the cerebral cortex and hippocampus of mice. In conclusion, the present study evidenced the in vitro anticholinesterase effect of two new selanyl amide derivatives in the cerebral structures of mice. Moreover, compound 1, a selanyl amide derivative containing a furan ring, demonstrated antiamnesic action due to its antioxidant and anticholinesterase activities in cerebral structures.

20(S)-protopanaxadiol promotes the migration, proliferation, and differentiation of neural stem cells by targeting GSK-3β in the Wnt/GSK-3β/β-catenin pathway

BACKGROUND

Active natural ingredients, especially small molecules, have recently received wide attention as modifiers used to treat neurodegenerative disease by promoting neurogenic regeneration of neural stem cell (NSC) in situ. 20(S)-protopanaxadiol (PPD), one of the bioactive ingredients in ginseng, possesses neuroprotective properties. However, the effect of PPD on NSC proliferation and differentiation and its mechanism of action are incompletely understood.

METHODS

In this study, we investigated the impact of PPD on NSC proliferation and neuronal lineage differentiation through activation of the Wnt/glycogen synthase kinase (GSK)-3β/β-catenin pathway. NSC migration and proliferation were investigated by neurosphere assay, Cell Counting Kit-8 assay, and EdU assay. NSC differentiation was analyzed by Western blot and immunofluorescence staining. Involvement of the Wnt/GSK3β/β-catenin pathway was examined by molecular simulation and Western blot and verified using gene transfection.

RESULTS

PPD significantly promoted neural migration and induced a significant increase in NSC proliferation in a time- and dose-dependent manner. Furthermore, a remarkable increase in antimicrotubule-associated protein 2 expression and decrease in nestin protein expression were induced by PPD. During the differentiation process, PPD targeted and stimulated the phosphorylation of GSK-3β at Ser9 and the active forms of β-catenin, resulting in activation of the Wnt/GSK-3β/β-catenin pathway. Transfection of NSCs with a constitutively active GSK-3β mutant at S9A significantly hampered the proliferation and neural differentiation mediated by PPD.

CONCLUSION

PPD promotes NSC proliferation and neural differentiation in vitro via activation of the Wnt/GSK-3β/β-catenin pathway by targeting GSK-3β, potentially having great significance for the treatment of neurodegenerative diseases.

Oxidative stress in alzheimer's disease: A review on emergent natural polyphenolic therapeutics

OBJECTIVES

The aim of this research was to review the literature on Alzheimer's disease (AD) with a focus on polyphenolics as antioxidant therapeutics.

DESIGN

This review included a search of the literature up to and including September 2019 in PubMed and MEDLINE databases using search terms that included: Alzheimer's Disease, Aβ peptide, tau, oxidative stress, redox, oxidation, therapeutic, antioxidant, natural therapy, polyphenol. Any review articles, case studies, research reports and articles in English were identified and subsequently interrogated. Citations within relevant articles were also examined for consideration in this review.

RESULTS

Alzheimer's disease is a neurodegenerative disorder that is clinically characterised by the progressive deterioration of cognitive functions and drastic changes in behaviour and personality. Due to the significant presence of oxidative damage associated with abnormal Aβ accumulation and neurofibrillary tangle deposition in AD patients' brains, antioxidant drug therapy has been investigated as potential AD treatment. In particular, naturally occurring compounds, such as plant polyphenols, have been suggested to have potential neuroprotective effects against AD due to their diverse array of physiological actions, which includes potent antioxidant effects.

CONCLUSIONS

The impact of oxidative stress and various mechanisms of pathogenesis in AD pathophysiology was demonstrated along with the therapeutic potential of emergent antioxidant drugs to address such mechanism of oxidation.

Future Therapeutic Perspectives into the Alzheimer's Disease Targeting the Oxidative Stress Hypothesis

Alzheimer's disease (AD) is a neurodegenerative disease that is usually accompanied by aging, increasingly being the most common cause of dementia in the elderly. This disorder is characterized by the accumulation of beta amyloid plaques (Aβ) resulting from impaired amyloid precursor protein (APP) metabolism, together with the formation of neurofibrillary tangles and tau protein hyperphosphorylation. The exacerbated production of reactive oxygen species (ROS) triggers the process called oxidative stress, which increases neuronal cell abnormalities, most often followed by apoptosis, leading to cognitive dysfunction and dementia. In this context, the development of new therapies for the AD treatment is necessary. Antioxidants, for instance, are promising species for prevention and treatment because they are capable of disrupting the radical chain reaction, reducing the production of ROS. These species have also proven to be adjunctive to conventional treatments making them more effective. In this sense, several recently published works have focused their attention on oxidative stress and antioxidant species. Therefore, this review seeks to show the most relevant findings of these studies.

Alleviation of symptoms of Alzheimer's disease by diminishing Aβ neurotoxicity and neuroinflammation

Alzheimer's disease (AD) is one of the most prevailing neurodegenerative illnesses in the elderly. Accumulation of amyloid-β peptide (Aβ) and inflammation play critical roles in the pathogenesis and development of AD. Multi-target drugs may interdict the progress of AD through a synergistic mechanism. A neuromodulator, 2-((1H-benzo[d]imidazole-2-yl)methoxy)benzoic acid (BIBA), consisting of an Aβ-targeting group and a derivative of anti-inflammatory aspirin was designed as a potential anti-AD agent. BIBA exhibits a remarkable inhibitory effect on the self- and metal-induced Aβ aggregations and shows outstanding anti-inflammatory activity simultaneously. The neurotoxicity of Aβ aggregates is attenuated, and the production of pro-inflammatory cytokines (PICs), such as IL-6, IL-1β and TNF-α, in microglia stimulated by lipopolysaccharide (LPS) or Aβ is reduced. Owing to the synergy between the inhibition of Aβ oligomerization and downregulation of PICs, BIBA markedly prolongs the lifespan and relieves the Aβ-induced paralysis of Aβ-transgenic Caenorhabditis elegans, thus showing the potential to ameliorate the symptoms of AD through inhibiting Aβ neurotoxicity and deactivating microglia. These findings demonstrate that both Aβ aggregation and neuroinflammation are therapeutic targets for anti-AD drugs, and dual-functional agents that integrate anti-Aβ and anti-inflammatory capabilities have great advantages over the traditional single-target agents for AD treatment.

Can non-pharmacological interventions reduce hospital admissions in people with dementia? A systematic review

Background

People with dementia who are admitted to hospital have worse outcomes than those without dementia. Identifying interventions that could reduce the risk of hospitalisation in people with dementia has the potential to positively impact on lives of people with dementia. This review aimed to investigate whether there are non-pharmacological interventions that successfully reduce hospitalisation risk, length of stay and mortality in people with dementia.

Methods

7 electronic databases and trial registries were searched from inception to October 2018. We included randomised controlled trials that evaluated non-pharmacological interventions in out of hospital settings and targeted people with any type of dementia. All stages of the review process were performed by two reviewers. Risk of bias was assessed using the Cochrane Risk of Bias tool. We grouped studies based on intervention: care management, counselling/self-help, enhanced GP services or memory clinics, and physiotherapy or occupational therapy. Data were pooled within intervention categories using random effects meta-analysis.

Results

There was no evidence that any of the intervention categories were associated with reduced hospital admission or mortality. There was very weak evidence to suggest that care management interventions (mean difference, MD, -0.16, 95% CI -0.32, 0.01), physiotherapy/occupational therapy (MD -0.16, 95% CI -0.36, 0.03) and enhanced GP/memory clinics (MD -0.14, 95% CI -0.31, 0.03) were associated with small reductions in hospital stay. There was no evidence for an effect of counselling/self-help interventions on length of hospital stay.

Conclusions

Current evidence from randomised trials suggests no clear benefit or harm associated with any of interventions on risks of hospitalisation, duration of hospitalisation or death. Further research with the primary aim to reduce hospitalisation in people with dementia is required.

Plasmon-Activated Water Reduces Amyloid Burden and Improves Memory in Animals with Alzheimer's Disease

With the great extension of the human lifespan in recent times, many aging diseases have inevitably followed. Dementia is one of the most-commom neurodegenerative aging diseases, in which inflammation-related Alzheimer’s disease (AD) is the most prevalent cause of dementia. Amyloid accumulation in the brain, which occurs before any clinical presentations, might be the first and key step in the development of AD. However, many clinical trials have attempted to remove amyloid from brains of AD patients, but none has so far been successful. Negatively charged plasmon-activated water (PAW) is created by resonantly illuminated gold (Au) nanoparticles (NPs), which reduce the hydrogen-bonded (HB) structure of water. PAW was found to possess anti-oxidative and anti-inflammatory effects. Herein, we report on an innovative strategy to retard the progression of AD by the daily consumption of PAW instead of normal deionized (DI) water. APPswe/PS1dE9 transgenic mice were treated with PAW or DI water from the age of 5 months for the next 9 months. Encouragingly, compared to DI water-treated mice, mice treated with PAW presented better memory performance on a test of novel object recognition and had a significantly lower amyloid burden according to 18F-florbetapir amyloid-PET and phosphorylated (p)-tau burden according to Western blotting and immunohistochemistry measurements. There were no obvious side effects in PAW-treated mice. Collectively, our findings support that PAW was able to reduce the amyloid and p-tau burden and improve memory in an AD mouse model. However, the protein levels of molecules involved in amyloid metabolism and oligomeric amyloid did not change. We propose that the effects of PAW of reducing the amyloid burden and improving memory function cannot be attributed to synthesis/degradation of amyloid-βprotein but probably in preventing aggregation of amyloid-β proteins or other mechanisms, including anti-inflammation. Further applications of PAW in clinical trials to prevent the progression of AD are being designed.

Emerging therapeutic potentials of dual-acting MAO and AChE inhibitors in Alzheimer's and Parkinson's diseases

No drug has been approved to prevent neuronal cell loss in patients suffering from Parkinson's disease (PD) or Alzheimer's disease (AD); despite increased comprehension of the underlying molecular causes, therapies target cognitive functional improvement and motor fluctuation control. Drug design strategies that adopt the "one protein, one target" philosophy fail to address the multifactorial aetiologies of neurodegenerative disorders such as AD and PD optimally. On the contrary, restoring neurotransmitter levels by combined combinatorial inhibition of cholinesterases, monoamine oxidases, and adenosine A_2A A receptors, in conjunction with strategies to counter oxidative stress and beta-amyloid plaque accumulation, would constitute a therapeutically robust, multitarget approach. This extensive review delineates the therapeutic advantages of combining dual-acting molecules that inhibit monoamine oxidases and cholinesterases and/or adenosine A_2A A receptors, and describes the structure-activity relationships of compound classes that include, but are not limited to, alkaloids, coumarins, chalcones, donepezil-propargylamine conjugates, homoisoflavonoids, resveratrol analogs, hydrazones, and pyrazolines. In the wake of recent advances in network biology, in silico approaches, and omics, this review emphasizes the need to consider conceptually informed research strategies for drug discovery, in the context of the mounting burden posed by chronic neurodegenerative diseases with complex aetiologies and pathophysiologies involving multiple signalling pathways and numerous drug targets.

Effectiveness of Acupuncture for Alzheimer's Disease: An Updated Systematic Review and Meta-analysis

Acupuncture has reportedly improved memory and cognitive impairment in both animal and clinical studies. It may be an effective treatment for Alzheimer's disease (AD). The purpose of this meta-analysis was to review the effectiveness of acupuncture for the treatment of AD. Eight databases were searched for articles published up to and including July 2017, and 13 studies fulfilling the inclusion criteria were identified. The main outcomes assessed were clinical efficacy rate, Mini-Mental State Examination score, Ability of Daily Living Scale score, Alzheimer's Disease Assessment Scale-Cognition score, Hasegawa's Dementia Scale (HDS) score, and adverse events. The methodological quality of the articles was assessed using Cochrane's risk of bias. All the studies compared the efficacy of acupuncture with that of medication, and were published in Chinese journals. Meta-analysis revealed that acupuncture yielded positive results as determined via all the indexes scored except the HDS (95% CI -0.26 to 0.90, Z=0.35, P=0.73). Only one of the studies reported adverse events associated with acupuncture and medication. The rate of adverse events in the medication group was 13%. In most of the studies assessed in the current meta-analysis, acupuncture alone was better than conventional western medicines for the treatment of AD.

The antiapoptotic and antioxidative stress effects of Zhisanzhen in the Alzheimer's disease model rat

Zhisanzhen, a type of acupuncture method, has been commonly used in the treatment of various neurodegenerative disorders in clinics in China. The aim of this study was to confirm the effect of Zhisanzhen on Alzheimer's disease and the associated mechanism. We used D-galactose and Aβ1-40 injections to establish a rat model of AD. Rats were divided into four groups: normal group, AD group, AD+manual acupuncture (control) group, and AD+manual acupuncture (Zhisanzhen) group. Zhisanzhen was used to treat the AD model rats. We found that Zhisanzhen improved behavioral performance, reduced oxidative stress, increased the neurotransmitter acetylcholine concentration, reduced apoptosis in hippocampal neurons, and down-regulated the expression of apoptosis-related genes and proteins. Compared with those in the AD group, these parameters were clearly different in the Zhisanzhen control group (P<0.05). These results suggest that Zhisanzhen can markedly enhance learning and memory and reverse the symptoms of Alzheimer's disease in AD model rats, which may be related to the role of Zhisanzhen in increasing chAT and Ache activity, decreasing oxidative stress and inhibiting neuronal apoptosis.Video abstract: http://links.lww.com/WNR/A517.

Early growth response-1 regulates acetylcholinesterase and its relation with the course of Alzheimer's disease

Our previous studies showed that the transcription factor early growth response-1 (EGR1) may play a role in keeping the brain cholinergic function intact in the preclinical stages of Alzheimer's disease (AD). In order to elucidate the mechanisms involved, we first performed data mining on our previous microarray study on postmortem human prefrontal cortex (PFC) for the changes in the expression of EGR1 and acetylcholinesterase (AChE) and the relationship between them during the course of AD. The study contained 49 patients, ranging from non-demented controls (Braak stage 0) to late AD patients (Braak stage VI). We found EGR1-mRNA was high in early AD and decreased in late AD stages, while AChE-mRNA was stable in preclinical AD and slightly decreased in late AD stages. A significant positive correlation was found between the mRNA levels of these two molecules. In addition, we studied the relationship between EGR1 and AChE mRNA levels in the frontal cortex of 3-12-months old triple-transgenic AD (3xTg-AD) mice. EGR1- and AChE-mRNA were lower in 3xTg-AD mice compared with wild-type (WT) mice. A significant positive correlation between these two molecules was present in the entire group and in each age group of either WT or 3xTg-AD mice. Subsequently, AChE expression was determined following up- or down-regulating EGR1 in cell lines and the EGR1 levels were found to regulate AChE at both the mRNA and protein levels. Dual-luciferase assay and electrophoretic mobility shift assay in the EGR1-overexpressing cells were performed to determine the functionally effective binding sites of the EGR1 on the AChE gene promoter. We conclude that the EGR1 can upregulate AChE expression by a direct effect on its gene promoter, which may contribute significantly to the changes in cholinergic function in the course of AD. The 3xTg-AD mouse model only reflects later stage AD.

Active immunization with norovirus P particle-based amyloid-β chimeric protein vaccine induces high titers of anti-Aβ antibodies in mice

BACKGROUND

Active immunotherapy targeting amyloid-β (Aβ) is a promising treatment for Alzheimer's disease (AD). Numerous preclinical studies and clinical trials demonstrated that a safe and effective AD vaccine should induce high titers of anti-Aβ antibodies while avoiding the activation of T cells specific to Aβ.

RESULTS

An untagged Aβ1-6 chimeric protein vaccine against AD based on norovirus (NoV) P particle was expressed in Escherichia coli and obtained by sequential chromatography. Analysis of protein characteristics showed that the untagged Aβ1-6 chimeric protein expressed in soluble form exhibited the highest particle homogeneity, with highest purity and minimal host cell protein (HCP) and residual DNA content. Importantly, the untagged Aβ1-6 chimeric soluble protein could induce the strongest Aβ-specific humoral immune responses without activation of harmful Aβ-specific T cells in mice.

CONCLUSIONS

The untagged Aβ1-6 chimeric protein vaccine is safe and highly immunogenic. Further research will determine the efficacy in cognitive improvement and disease progression delay.