Role of inflammatory molecules in the Alzheimer's disease progression and diagnosis

Effects of resistance exercise on behavioral and molecular changes in transgenic female mice for Alzheimer's disease in early and advanced stages

Alzheimer's disease (AD) is a neurodegenerative condition that affects memory and cognition, with a higher prevalence in women. Given the lack of effective treatment, physical activity stands out as a complementary approach to prevent or delay disease progression. While numerous studies on humans and animals indicate that aerobic exercise induces brain changes, the impact of resistance exercise (RE) on AD is not fully understood.

OBJECTIVE

This study aimed to investigate the behavioral and molecular changes induced by RE in female transgenic mice with AD at the early and advanced stages of the disease.

MATERIALS AND METHODS

Adult (initial phase - 7 to 8 months of age, n = 32) and adult/elderly (advanced phase - 22 to 23 months of age, n = 32) female mice (2xTg-AD) for the APPSWE/PS1dE9 mutation were subjected to a four-week RE protocol. Mobility, anxiety-like behavior, long-term memory (LTM), and depressive-like behavior were assessed. Beta-amyloid (βA) and cytokines were quantified using the ELISA technique.

RESULTS

There was a progressive increase in strength in both trained groups at different ages. RE reversed memory deficits only in adult AD animals and the anxiety-like behavior only in adult/elderly AD animals. RE reversed depressive-like behavior in adult and adult/elderly AD animals. RE reduced βA only in adult AD animals. RE modified the expression of several cytokines in animals in the early and advanced stage of AD.

CONCLUSION

RE can be a promising strategy to minimize the deleterious effects of AD; however, its effectiveness may be more limited to the early stages of the disease.

Fritaipaines A - J, isosteroidal alkaloids with anti-neuroinflammatory activity from the bulbs of Fritillaria taipaiensis

Ten new isosteroidal alkaloids, fritaipaines A - J (1-10), and six known congeners (11-16) were isolated from the bulbs of Fritillaria taipaiensis. The planar structure of these compounds as well as the absolute configuration, were fully elucidated based on spectroscopic and single-crystal X-ray diffraction data analysis and electronic circular dichroism (ECD) methods. Fritaipaines A (1) and B (2) are rare C26 cevanine-type alkaloids having C-18 nor carbon skeleton. Fritaipaines C - F (3-6) are the first examples of jervine-type alkaloids featuring an inversed E/F ring moiety. The characteristic 13C NMR data for judging E/F rings-inversion of jervine-type alkaloids were summarized. Compounds 5, 9, and 16 exhibited potent nitric oxide (NO) inhibitory activity in lipopolysaccharide (LPS) stimulated BV-2 cells with IC50 values of 3.7 ± 0.4, 10.3 ± 1.1, and 6.9 ± 0.7 μM, respectively. All compounds showed weak or no acetylcholinesterase (AChE) inhibition as determined by the Ellman's method. The results of network pharmacology experiments predicted that the anti-Alzheimer's disease (AD) effect of fritaipaine E (5) was related to 9 signaling pathways and 5 core targets, including SRC, PIK3CA, AKT1, EGFR, and IGF1R. Molecular docking simulations highlighted interactions between 5 and core targets, showing inhibitory effects on AD.

Phytochemical analysis and neuroprotective potential of Achillea santolina L. fractions

Phytochemical characterization, and biological assessment of the neuroprotective activities of Achillea santolina L. methanolic extract (AS), its methylene chloride fraction (MF), butanol fraction (BF) and their isolated compounds were investigated. Twenty-two compounds were identified and quantified in AS using HPLC. Luteolin and kaempferol were isolated from MF. Isovitexin and kaempferol 3-O-glucoside were isolated from BF. The anti-inflammatory activity of the isolated compounds was determined by employing cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitory assays. Neuroprotective activities of AS, MF and BF were investigated against monosodium glutamate (MSG) induced neurotoxicity in rats. Brain damage amended significantly as indicated by the decreased lactate dehydrogenase and tumor necrosis factor. Brain oxidative status was restored as indicated by increased glutathione and decreased lipid peroxidation. AS, MF and BF markedly attenuated histopathological alterations in cerebral cortex and downregulated expression of COX-2, IL-1B, IL-10 genes. The affinity of the isolated compounds for Human Heme Oxygenase-1, 5-LOX, Kelch-like ECH-associated protein and COX-2 was studied. Molecular dynamics simulation and ADME study proved that isovitexin has stable conformations and binding patterns with the active sites of the studied enzymes. For the first time, the neuroprotective potential of AS, fractions and isolated compounds was determined supported by anti-inflammatory study.

Unmasking a Paradox: Roles of the PD-1/PD-L1 Axis in Alzheimer's Disease-Associated Neuroinflammation

Alzheimer's disease (AD) represents the most prevalent form of dementia, characterized by progressive cognitive impairment and chronic neuroinflammation. Immune checkpoint inhibitors (ICIs), including anti-programmed cell death (PD)-1 and anti-PD-L1, signify a revolutionary advancement in cancer treatment by preventing T-cell exhaustion; however, their therapeutic application in AD presents a conundrum. Hypothesis: Recent preclinical studies indicate that PD-1 inhibition in AD mouse models induces an interferon-gamma (IFN-γ)-mediated response, leading to increased recruitment of monocyte-derived macrophages into the brain, enhanced clearance of amyloid-beta (Aβ) plaques, and improved cognitive performance. Nonetheless, this therapeutic effect is counterbalanced by the potential for exacerbated neuroinflammation, as PD-1/PD-L1 blockade may potentiate pro-inflammatory T helper (Th)1 and Th17 responses. In this review, we critically discuss the pertinent pro-inflammatory and neuroprotective facets of T cell biology in the pathogenesis of AD, emphasizing the potential for modulation of the PD-1/PD-L1 axis to influence both Aβ clearance and the dynamics of neuroinflammatory processes. In summary, we determine that ICIs are promising tools for reducing AD pathology and improving cognition. However, it is essential to refine treatment protocols and carefully select patients to optimize neuroprotective effects while adequately considering inflammatory risks.

Efficacy and Safety of Bilateral Deep Brain Stimulation (DBS) for Severe Alzheimer's Disease: A Comparative Analysis of Fornix Versus Basal Ganglia of Meynert

BACKGROUND

Deep brain stimulation (DBS) is a novel therapy for severe Alzheimer's disease (AD). However, there is an ongoing debate regarding the optimal target for DBS, particularly the fornix and the basal ganglia of Meynert (NBM).

OBJECTIVE

This study aimed to investigate the safety and efficacy of DBS for severe AD and to compare the fornix and the NBM as potential targets.

METHODS

We conducted a prospective, nonrandomized clinical study involving 20 patients with severe AD (MMSE score 0 to 10, CDR level 3) from January 2015 to August 2022, comprising 12 males and eight females, with a mean age of 59.05 ± 6.45 years. All patients underwent DBS treatment, among which 14 received bilateral fornix implantation, while six received bilateral implantation in the NBM. Electrical stimulation commenced 1 month postoperatively. We assessed the patients before surgery, followed by evaluations at 1 month, 3 months, 6 months, and 12 months poststimulation. Primary outcome measures focused on changes in cognitive function, assessed using the MMSE, MoCA, ADAS-Cog, and CDR scales. Secondary measures encompassed quality of life, caregiver burden, neuropsychiatric symptoms, and sleep disturbances, evaluated through the BI, FAQ, FIM, ZBI, NPI, HAMA, HAMD, and PSQI scales.

RESULTS

All patients tolerated DBS well, with no serious adverse effects reported. Early on, DBS significantly improved cognitive function and quality of life. Long-term benefits include the improvement of neuropsychiatric symptoms and sleep disorders and the alleviation of caregiver burden. Comparison between DBS targeting the NBM and fornix revealed no significant differences in overall scale scores. However, upon deeper analysis, NBM-DBS exhibited a more pronounced improvement in neuropsychiatric symptoms, particularly in NPI scores.

CONCLUSION

DBS is a potential therapeutic approach for severe AD, capable of improving patients' cognitive function, quality of life, and neuropsychiatric symptoms. Notably, NBM-DBS showed distinct advantages in ameliorating neuropsychiatric symptoms, providing valuable insights for clinically selecting the optimal DBS target.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03115814.

Unveiling the Etiopathogenic Role of Epstein-Barr Virus in Periodontitis

Periodontitis, a prevalent and costly oral disease, remains incompletely understood in its etiopathogenesis. The conventional model attributes it to pathogenic bacteria, but emerging evidence suggests dysbiosis involving bacteria, herpesviruses, and an exaggerated host immune response. Among herpesviruses, Epstein-Barr virus (EBV) closely links to severe periodontitis, yet the mechanisms underlying EBV-related pathogenesis remain elusive. This study examined the presence, methylation patterns, and infection states of EBV in gingival tissues from healthy patients and those with periodontitis. It also assessed gene expression differences associated with EBV through whole-genome transcriptomic profiling in healthy and periodontitis-affected tissues. EBV DNA was found at similar frequencies in healthy and periodontitis tissues, suggesting common EBV infection even before disease manifestation. In healthy tissues, mostly unmethylated EBV genomes indicated lytic infection in gums, consistent with the literature on lytic EBV spread in epithelia and continual significant virus release in the saliva of healthy carriers. Conversely, EBV DNA in periodontitis tissues showed both methylated and unmethylated patterns, suggesting a mix of latent and lytic genomes. This indicates the coexistence of latent EBV in B-cells and lytic EBV in plasma cells (PCs), linking EBV presence with both cell types in periodontitis. Whole-genome transcriptomic analysis revealed distinct expression profiles in EBV-positive periodontitis tissues, with upregulated genes associated with inflammatory/immune responses and B-cell and PC markers, while downregulated genes were related to epithelial structure and organization. The EBV-positive periodontitis signature differed distinctly from that of EBV-positive healthy gums, eliciting only a typical viral-induced immune response. These findings provide new insights into EBV physiopathology in the gum, notably assigning a direct etiopathogenetic contribution to EBV in periodontitis. The results suggest a model where EBV can commonly, and apparently asymptomatically, spread in healthy gingiva but may also aggravate inflammation in the context of gum dysbiosis, involving infiltration of B-cells and PCs and loss of epithelial integrity.

Uncovering the intricacies of IGF-1 in Alzheimer's disease: new insights from regulation to therapeutic targeting

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-β plaques and tau tangles, leading to cognitive decline and dementia. Insulin-like Growth Factor-1 (IGF-1) is similar in structure to insulin and is crucial for cell growth, differentiation, and regulating oxidative stress, synaptic plasticity, and mitochondrial function. IGF-1 exerts its physiological effects by binding to the IGF-1 receptor (IGF-1R) and activating PI3K/Akt pathway. In addition to the physiological activities in the brain, numerous studies point to a potential protective role of the IGF-1 pathway in the pathogenesis of neurodegenerative diseases, such as AD. Interestingly, patients with AD often exhibit altered insulin and IGF-1 levels, along with an inadequate insulin response. Dysregulation of IGF-1 signaling contributes to hyperphosphorylation of tau, NFT accumulation, increased β- and γ-secretase activity, elevated Aβ production, and impaired Aβ clearance, highlighting the need to explore the role of this signaling for potential therapeutic targets of AD. This review explores the role of IGF signaling in AD pathology, highlighting IGF-1 as a promising therapeutic target due to its significant involvement in disease mechanisms. Modulating IGF-1 activity could help mitigate neurodegeneration and preserve cognitive function in AD. A comprehensive understanding of the mechanisms underlying IGF-1 dysregulation is crucial for developing targeted therapeutic strategies to address the complex and multifaceted nature of AD.

Newer Therapeutic Approaches in Treating Alzheimer's Disease: A Comprehensive Review

Alzheimer's disease (AD) is an aging-related irreversible neurodegenerative disease affecting mostly the elderly population. The main pathological features of AD are the extracellular Aβ plaques generated by APP cleavage through the amyloidogenic pathway, the intracellular neurofibrillary tangles (NFT) resulting from the hyperphosphorylated tau proteins, and cholinergic neurodegeneration. However, the actual causes of AD are unknown, but several studies suggest hereditary mutations in PSEN1 and -2, APOE4, APP, and the TAU genes are the major perpetrators. In order to understand the etiology and pathogenesis of AD, various hypotheses are proposed. These include the following hypotheses: amyloid accumulation, tauopathy, inflammation, oxidative stress, mitochondrial dysfunction, glutamate/excitotoxicity, cholinergic deficiency, and gut dysbiosis. Currently approved therapeutic interventions are donepezil, galantamine, and rivastigmine, which are cholinesterase inhibitors (ChEIs), and memantine, which is an N-methyl-d-aspartate (NMDA) antagonist. These treatment strategies focus on only symptomatic management of AD by attenuating symptoms but not regeneration of neurons or clearance of Aβ plaques and hyperphosphorylated Tau. This review focuses on the pathophysiology, novel therapeutic targets, and disease-altering treatments such as α-secretase modulators, active immunotherapy, passive immunotherapy, natural antioxidant products, nanomaterials, antiamyloid therapy, tau aggregation inhibitors, transplantation of fecal microbiota or stem cells, and microtubule stabilizers that are in clinical trials or still under investigation.

Discovery of novel fatty acid amide hydrolase (FAAH) inhibitors as anti-alzheimer agents via in-silico-based drug design, virtual screening, molecular docking, molecular dynamics simulation, DFT, and non-clinical studies

AIM

To identify some novel fatty acid hydrolase (FAAH) inhibitors that may contribute to the treatment of Alzheimer's disease (AD).

METHODS

In-silico pharmacophore modelling including ligand-based pharmacophore modelling, virtual screening, molecular docking, molecular dynamics modelling, density functional theory and in-silico pharmacokinetics and toxicological studies were employed for the retrieving of novel FAAH inhibitors. Further, these compounds were evaluated for FAAH inhibitory activity using an in vitro enzymatic assay, and later, an in vivo streptozotocin (STZ)-induced AD model was examined in mice.

RESULTS

Using an in-silico pharmacophore modelling process with molecular docking, molecular dynamic modelling, density functional theory and in-silico pharmacokinetics and toxicological analysis, three compounds (NCI1697, NCI1001and NCI1041) were retrieved. The in vitro FAAH activity assay kit (Fluorometric) was employed to examine the FAAH inhibitory activity of identified compounds. Further, in in-vivo studies, treatment with these compounds at 2.5 and 5 mg/kg doses orally for 10 days restored the STZ-induced memory deficits in mice, as evident in the radial arm and Morris's water maze assays. Also, these compounds ameliorated oxidative stress profiles and neuroinflammatory biomarkers in mice. Interestingly, STZ-induced disturbance in gene expressions related to AD pathophysiology including endocannabinoid signalling neuroinflammation and neuroimmune signalling were also restored after the treatment. Histopathological findings also confirmed the improvement in the organization of cells and reduction in vacuolation in mice hippocampal tissue in treated mice.

CONCLUSION

The in-silico, in vitro and in-vivo findings collectively indicated that these compounds have impressive FAAH inhibitory activity and may be developed as therapeutic agents in the management of AD.

Brain interleukins and Alzheimer's disease

The central nervous system (CNS) is immune-privileged by several immuno-modulators as interleukins (ILs). ILs are cytokines secreted by immune cells for cell-cell signaling communications and affect the functions of the CNS. ILs were reported to orchestrate different molecular and cellular mechanisms of both physiological and pathological events, through overproduction or over-expression of their receptors. They interact with numerous receptors mediating pro-inflammatory and/or anti-inflammatory actions. Interleukins have been implicated to participate in neurodegenerative diseases. They play a critical role in Alzheimer's disease (AD) pathology which is characterized by the over-production of pro-inflammatory ILs. These may aggravate neurodegeneration, in addition to their contribution to detrimental mechanisms as oxidative stress, and excitotoxicity. However, recent research on the relation between ILs and AD revealed major discrepancies. Most of the major ILs were shown to play both pro- and anti-inflammatory roles in different experimental settings and models. The interactions between different ILs through shared pathways also add to the difficulty of drawing solid conclusions. In addition, targeting the different ILs has not yielded consistent results. The repeated failures of therapeutic drugs in treating AD necessitate the search for novel agents targeting multiple mechanisms of the disease pathology. In this context, the understanding of interleukins and their roles throughout the disease progression and interaction with other systems in the brain may provide promising therapeutic targets for the prevention or treatment of AD.

Dihydro-resveratrol ameliorates NLRP3 inflammasome-mediated neuroinflammation via Bnip3-dependent mitophagy in Alzheimer's disease

BACKGROUND AND PURPOSE

Dihydro-resveratrol (DHR), a polyphenol derivative, that has been demonstrated to suppress inflammation-mediated injury. However, it is still unknown whether it has anti-neuroinflammatory and neuroprotective effects, and a therapeutic action in Alzheimer's disease (AD).

EXPERIMENTAL APPROACH

The anti-inflammatory and anti-Alzheimer's disease actions of dihydro-resveratrol were investigated using lipopolysaccharide (LPS) and AD mice models, and primary microglial cells. The changes in behaviour in mice were detected by the Morris water maze test and open-field test. Flow cytometry assay, western blotting, immunofluorescence assays and co-immunoprecipitation were used to investigate the changes in the NLRP3 inflammasome activation and mitophagy.

KEY RESULTS

In this study, in vivo observations indicated that the administration of dihydro-resveratrol (DHR) dramatically restored spatial learning, memory ability, autophagy and mitophagy, attenuated NLRP3 inflammasome activation, neuroinflammation and amyloid precursor protein pathology in LPS mice and AD mice. In addition, the inhibition of autophagy and mitophagy, or the activation of NLRP3 in vivo greatly abolished DHR-generated therapeutic efficacy on neuroinflammation, amyloid precursor protein pathology and cognitive loss. Further examination indicated that the application of DHR after the LPS and ATP exposure significantly inhibited the NLRP3 inflammasome activation, neuroinflammation and enhanced autophagic and mitophagic activation in microglia. Additionally, in vitro results show that DHR protects microglial cells against LPS and ATP-induced cytotoxicity by inhibiting NLRP3 inflammasome through activating Bnip3-dependent mitophagy and ULK phosphorylation.

CONCLUSIONS AND IMPLICATIONS

In summary, these findings suggest that dihydro-resveratrol (DHR) possesses potent anti-neuroinflammatory property and can act as a potential therapeutic agent for the treatment of AD.

Inflammatory biomarkers profiles and cognition among older adults

Inflammation plays a major role in cognitive aging. Most studies on peripheral inflammation and cognitive aging focused on selected major inflammatory biomarkers. However, inflammatory markers are regulated and influenced by each other, and it is therefore important to consider a more comprehensive panel of markers to better capture diverse immune pathways and characterize the overall inflammatory profile of individuals. We explored 23 circulating inflammatory biomarkers using data from 1,743 participants without dementia (≥ 65 years-old) from the community-based, multiethnic Washington Heights Inwood Columbia Aging Project. Using principal component analysis (PCA), we developed six inflammatory profiles (PC-1 to PC-6) based on these 23 biomarkers and tested the association of resulting inflammatory profile with cognitive decline, over up to 12 years of follow-up. PC-1 described a pro-inflammatory profile characterized by high positive loadings for pro-inflammatory biomarkers. A higher PC-1 score was associated with lower baseline cognitive performances. No association of this profile with cognitive decline was observed in longitudinal analysis. However, PC-5 characterized by high PDGF-AA and RANTES was associated with a faster cognitive decline. Among older adults, a circulating pro-inflammatory immune profile is associated with lower baseline cognitive performance, and some specific pro-inflammatory cytokines might be associated with faster cognitive decline.

Fecal microbiota transplantation attenuates Alzheimer's disease symptoms in APP/PS1 transgenic mice via inhibition of the TLR4-MyD88-NF-κB signaling pathway-mediated inflammation

Alzheimer's disease (AD) is a prevalent and progressive neurodegenerative disorder that is the leading cause of dementia. The underlying mechanisms of AD have not yet been completely explored. Neuroinflammation, an inflammatory response mediated by certain mediators, has been exhibited to play a crucial role in the pathogenesis of AD. Additionally, disruption of the gut microbiota has been found to be associated with AD, and fecal microbiota transplantation (FMT) has emerged as a potential therapeutic approach. However, the precise mechanism of FMT in the treatment of AD remains elusive. In this study, FMT was performed by transplanting fecal microbiota from healthy wild-type mice into APP/PS1 mice (APPswe, PSEN1dE9) to assess the effectiveness of FMT in mitigating AD-associated inflammation and to reveal its precise mechanism of action. The results demonstrated that FMT treatment improved cognitive function and reduced the expression levels of inflammatory factors by regulating the TLR4/MyD88/NF-κB signaling pathway in mice, which was accompanied by the restoration of gut microbial dysbiosis. These findings suggest that FMT has the potential to ameliorate AD symptoms and delay the disease progression in APP/PS1 mice.

Calcium balance through mutual orchestrated inter-organelle communication: A pleiotropic target for combating Alzheimer's disease

Dysfunctional intraneuronal organelles in Alzheimer's Disease (AD) propel aberrant calcium handling, triggering molecular miscommunication within organelles such as mitochondria, endoplasmic reticulum, and lysosomes. This disruption in organelle function not only impairs cellular homeostasis but also exacerbates neurodegenerative processes involving the accumulation of amyloid-β (Aβ) and hyperphosphorylated tau, amplifying the disease's vicious cycle. In this review, the concept of Mutual Orchestrated Inter-organelle Communication (MOIC) proposes potential therapeutic avenues for restoring Ca2+ homeostasis in AD, offering a theoretical framework for developing disease-modifying treatments. The intricate nature of AD necessitates a shift towards combination therapies targeting MOIC-associated pathways, presenting a more effective approach than monotherapy.

Gut Microbiota and Alzheimer Disease

ABSTRACT

The hallmarks of Alzheimer's disease (AD) include brain dysfunction and the buildup of amyloid and tau proteins. The onset of dementia is one of the latter symptoms. Imaging diagnostics allowed for the detection of amyloid buildup in the brain 10-20 years before the emergence of overt signs of the disease. The application of imaging diagnostic techniques allowed for this identification. Within the next few decades, the incidence and frequency of this disease are expected to reach epidemic proportions unless measures are done to stop or slow its growth. However, unless action is taken to slow or stop the disease's progression, it will continue to threaten the health of the general public. Recently, there has been some speculation that the gut flora might contribute to the development of AD. Not only that, but the rapidly expanding ischemia etiology is another possible contributor to the issue. Rumor has it that there's a network connecting the brain and the stomach called the "gut-brain-microbiota axis." The hypothesis is based on this network. Furthermore, a large amount of evidence implies that the gut microbiota (GMB) could potentially contribute to the onset of AD. It has been suggested that the GMB could play a role in the onset of AD. This notion has been bolstered by new studies. It is quite probable that this review will address the prospect of a link between the microbiome and AD. This concept could be explored as a potential therapy or preventative measure. Some techniques that show promise as new treatments for AD include changes to the GMB, which can be achieved through dietary changes or positive microflora interventions, and changes to microbiological partners and their products, like amyloid protein.

Homocysteine decreases VEGF, EGF, and TrkB levels and increases CCL5/RANTES in the hippocampus: Neuroprotective effects of rivastigmine and ibuprofen

Homocysteine (Hcy) is produced through methionine transmethylation. Elevated Hcy levels are termed Hyperhomocysteinemia (HHcy) and represent a risk factor for neurodegenerative conditions such as Alzheimer's disease. This study aimed to explore the impact of mild HHcy and the neuroprotective effects of ibuprofen and rivastigmine via immunohistochemical analysis of glial markers (Iba-1 and GFAP). Additionally, we assessed levels of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), chemokine ligand 5 (CCL5/RANTES), CX3C chemokine ligand 1 (CX3CL1), and the NGF/p75NTR/tropomyosin kinase B (TrkB) pathway in the hippocampus of adult rats. Mild chronic HHcy was induced chemically in Wistar rats by subcutaneous administration of Hcy (4 mg/kg body weight) twice daily for 30 days. Rivastigmine (0.5 mg/kg) and ibuprofen (40 mg/kg) were administered intraperitoneally once daily. Results revealed elevated levels of CCL5/RANTES and reduced levels of VEGF, EGF, and TrkB in the hippocampus of HHcy-exposed rats. Rivastigmine mitigated the neurotoxic effects of HHcy by increasing TrkB and VEGF levels. Conversely, ibuprofen attenuated CCL5/RANTES levels against the neurotoxicity of HHcy, significantly reducing this chemokine's levels. HHcy-induced neurochemical impairment in the hippocampus may jeopardize neurogenesis, synapse formation, axonal transport, and inflammatory balance, leading to neurodegeneration. Treatments with rivastigmine and ibuprofen alleviated some of these detrimental effects. Reversing HHcy-induced damage through these compounds could serve as a potential neuroprotective strategy against brain damage.

Omnidirectional improvement of mitochondrial health in Alzheimer's disease by multi-targeting engineered activated neutrophil exosomes

Alzheimer's disease (AD) is one kind of devasting neurodegenerative disorders affecting over 50 million people worldwide. Multi-targeted therapy has emerged as a new treatment for diagnosing and alleviating the pathogenesis process of AD; however, the current strategy is limited by its unsatisfactory efficiency. In our study, engineered activated neutrophil-derived exosomes (MP@Cur-MExo) were developed to improve the mitochondrial function in neurons by targeting and alleviating Aβ-induced neurotoxicity. MP@Cur-MExo are exosomes derived from IL-8-stimulated neutrophils decorated with mitochondria targeting ligand and Aβ targeted ligand modified SPION. Engineered exosomes can be cleaved by matrix metallopeptidase-2, which is overexpressed in the AD brain. Consequently, the released SPION and Curcumin-loaded engineered exosomes collaboratively protected neuron cells against Aβ-induced mitochondrial deficiency. In addition, MP@Cur-MExo effectively accumulated in the inflamed region of AD brain at an early stage, allowing early diagnosis of AD through bimodal (MRI/IVIS) imaging. Importantly, in a mouse model at an early stage of AD, intravenously injected MP@Cur-MExo restored mitochondrial function and reduced Aβ-induced mitochondrial damage, thereby attenuating AD progression. In conclusion, our designed engineered exosomes demonstrated that omnidirectional improvement of mitochondrial function can serve as a novel and practical approach for the diagnosis and treatment of neurodegenerative diseases. This study also reveals a promising therapeutic agent for impeding AD progression for future clinical applications.

Exploring the effect of gut microbiome on Alzheimer's disease

Alzheimer's disease (AD) is the most widespread and irreversible form of dementia and accounts for more than half of dementia cases. The most significant risk factors for AD are aging-related exacerbations, degradation of anatomical pathways, environmental variables and mitochondrial dysfunction. Finding a decisive therapeutic solution is a major current issue. Nuanced interactions between major neuropathological mechanisms in AD in patients and microbiome have recently gained rising attention. The presence of bacterial amyloid in the gut triggers the immune system, resulting in increased immune feedbacks and endogenous neuronal amyloid within the CNS. Also, early clinical research revealed that changing the microbiome with beneficial bacteria or probiotics could affect brain function in AD. New approaches focus on the possible neuroprotective action of disease-modifying medications in AD. In the present review, we discuss the impact of the gut microbiota on the brain and review emerging research that suggests a disruption in the microbiota-brain axis can affect AD by mediating neuroinflammation. Such novel methods could help the development of novel therapeutics for AD.

Microglia-specific IL-10 gene delivery inhibits neuroinflammation and neurodegeneration in a mouse model of Parkinson's disease

Neuroinflammation plays a key role in exacerbating dopaminergic neuron (DAN) loss in Parkinson's disease (PD). However, it remains unresolved how to effectively normalize this immune response given the complex interplay between the innate and adaptive immune responses occurring within a scarcely accessible organ like the brain. In this study, we uncovered a consistent correlation between neuroinflammation, brain parenchymal lymphocytes, and DAN loss among several commonly used mouse models of PD generated by a variety of pathological triggers. We validated a viral therapeutic approach for the microglia-specific expression of interleukin 10 (IL-10) to selectively mitigate the excessive inflammatory response. We found that this approach induced a local nigral IL-10 release that alleviated DAN loss in mice overexpressing the human SNCA gene in the substantia nigra. Single-cell transcriptomics revealed that IL-10 induced the emergence of a molecularly distinct microglial cell state, enriched in markers of cell activation with enhanced expression of prophagocytic pathways. IL-10 promoted microglial phagocytotic and clearance activities in vitro and reduced αSYN aggregate burden in the nigral area in mice overexpressing SNCA. Furthermore, IL-10 stimulated the differentiation of CD4+ T lymphocytes into active T regulatory cells and promoted inhibitory characteristics in CD8+ T cells. In summary, our results show that local and microglia-specific IL-10 transduction elicited strong immunomodulation in the nigral tissue with enhanced suppression of lymphocyte toxicity that was associated with DAN survival. These results offer insights into the therapeutic benefits of IL-10 and showcase a promising gene delivery approach that could minimize undesired side effects.

Prodromic Inflammatory-Oxidative Stress in Peritoneal Leukocytes of Triple-Transgenic Mice for Alzheimer's Disease

Inflammatory-oxidative stress is known to be pivotal in the pathobiology of Alzheimer's disease (AD), but the involvement of this stress at the peripheral level in the disease's onset has been scarcely studied. This study investigated the pro-inflammatory profile and oxidative stress parameters in peritoneal leukocytes from female triple-transgenic mice for AD (3xTgAD) and non-transgenic mice (NTg). Peritoneal leukocytes were obtained at 2, 4, 6, 12, and 15 months of age. The concentrations of TNFα, INFγ, IL-1β, IL-2, IL-6, IL-17, and IL-10 released in cultures without stimuli and mitogen concanavalin A and lipopolysaccharide presence were measured. The concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), lipid peroxidation, and Hsp70 were also analyzed in the peritoneal cells. Our results showed that although there was a lower release of pro-inflammatory cytokines by 3xTgAD mice, this response was uncontrolled and overstimulated, especially at a prodromal stage at 2 months of age. In addition, there were lower concentrations of GSH in leukocytes from 3xTgAD and higher amounts of lipid peroxides at 2 and 4 months, as well as, at 6 months, a lower concentration of Hsp70. In conclusion, 3xTgAD mice show a worse pro-inflammatory response and higher oxidative stress than NTg mice during the prodromal stages, potentially supporting the idea that Alzheimer's disease could be a consequence of peripheral alteration in the leukocyte inflammation-oxidation state.

Pharmacological mTOR inhibitors in ameliorating Alzheimer's disease: current review and perspectives

Traditionally, pharmacological mammalian/mechanistic targets of rapamycin (mTOR) kinase inhibitors have been used during transplantation and tumor treatment. Emerging pre-clinical evidence from the last decade displayed the surprising effectiveness of mTOR inhibitors in ameliorating Alzheimer's Disease (AD), a common neurodegenerative disorder characterized by progressive cognitive function decline and memory loss. Research shows mTOR activation as an early event in AD development, and inhibiting mTOR may promote the resolution of many hallmarks of Alzheimer's. Aberrant protein aggregation, including amyloid-beta (Aβ) deposition and tau filaments, and cognitive defects, are reversed upon mTOR inhibition. A closer inspection of the evidence highlighted a temporal dependence and a hallmark-specific nature of such beneficial effects. Time of administration relative to disease progression, and a maintenance of a functional lysosomal system, could modulate its effectiveness. Moreover, mTOR inhibition also exerts distinct effects between neurons, glial cells, and endothelial cells. Different pharmacological properties of the inhibitors also produce different effects based on different blood-brain barrier (BBB) entry capacities and mTOR inhibition sites. This questions the effectiveness of mTOR inhibition as a viable AD intervention strategy. In this review, we first summarize the different mTOR inhibitors available and their characteristics. We then comprehensively update and discuss the pre-clinical results of mTOR inhibition to resolve many of the hallmarks of AD. Key pathologies discussed include Aβ deposition, tauopathies, aberrant neuroinflammation, and neurovascular system breakdowns.

New neuroprotective derivatives of cinnamic acid by biotransformation

Microbial transformation is extensively utilized to generate new metabolites in bulk amounts with more specificity and improved activity. As cinnamic acid was reported to exhibit several important pharmacological properties, microbial transformation was used to obtain its new derivatives with enhanced biological activities. By manipulating the 2-stage fermentation protocol of biotransformation, five metabolites were produced from cinnamic acid. Two of them were new derivatives; N-propyl cinnamamide 2̲ and 2-methyl heptyl benzoate 3̲ produced by Alternaria alternata. The other 3 metabolites, p-hydroxy benzoic acid 4̲, cinnamyl alcohol 5̲ and methyl cinnamate 6̲, were produced by Rhodotorula rubra, Rhizopus species and Penicillium chrysogeneum, respectively. Cinnamic acid and its metabolites were evaluated for their cyclooxygenase (COX) and acetylcholinesterase (AChE) inhibitory activities. Protection against H2O2 and Aβ1-42 induced-neurotoxicity in human neuroblastoma (SH-SY5Y) cells was also monitored. Metabolite 4̲ was more potent as a COX-2 inhibitor than the parent compound with an IC50 value of 1.85 ± 0.07 μM. Out of the tested compounds, only metabolite 2̲ showed AChE inhibitory activity with an IC50 value of 8.27 μM. These results were further correlated with an in silico study of the binding interactions of the active metabolites with the active sites of the studied enzymes. Metabolite 3̲ was more potent as a neuroprotective agent against H2O2 and Aβ1-42 induced-neurotoxicity than catechin and epigallocatechin-3-gallate as positive controls. This study suggested the two new metabolites 2̲ and 3̲ along with metabolite 4̲ as potential leads for neurodegenerative diseases associated with cholinergic deficiency, neurotoxicity or neuroinflammation.

Exploring the mechanisms of kaempferol in neuroprotection: Implications for neurological disorders

Kaempferol, a flavonoid compound found in various fruits, vegetables, and medicinal plants, has garnered increasing attention due to its potential neuroprotective effects in neurological diseases. This research examines the existing literature concerning the involvement of kaempferol in neurological diseases, including stroke, Parkinson's disease, Alzheimer's disease, neuroblastoma/glioblastoma, spinal cord injury, neuropathic pain, and epilepsy. Numerous in vitro and in vivo investigations have illustrated that kaempferol possesses antioxidant, anti-inflammatory, and antiapoptotic properties, contributing to its neuroprotective effects. Kaempferol has been shown to modulate key signaling pathways involved in neurodegeneration and neuroinflammation, such as the PI3K/Akt, MAPK/ERK, and NF-κB pathways. Moreover, kaempferol exhibits potential therapeutic benefits by enhancing neuronal survival, attenuating oxidative stress, enhancing mitochondrial calcium channel activity, reducing neuroinflammation, promoting neurogenesis, and improving cognitive function. The evidence suggests that kaempferol holds promise as a natural compound for the prevention and treatment of neurological diseases. Further research is warranted to elucidate the underlying mechanisms of action, optimize dosage regimens, and evaluate the safety and efficacy of this intervention in human clinical trials, thereby contributing to the advancement of scientific knowledge in this field.

Nanotechnology-based Drug Delivery for Alzheimer's and Parkinson's Diseases

The delivery of drugs to the brain is quite challenging in the treatment of the central nervous system (CNS) diseases due to the blood-brain barrier and the blood-cerebrospinal fluid barrier. However, significant developments in nanomaterials employed by nanoparticle drug-delivery systems have substantial potential to cross or bypass these barriers leading to enhanced therapeutic efficacies. Advances in nanoplatform, nanosystems based on lipids, polymers and inorganic materials have been extensively studied and applied in treating Alzheimer's and Parkinson's diseases. In this review, various types of brain drug delivery nanocarriers are classified, summarized, and their potential as drug delivery systems in Alzheimer's and Parkinson's diseases is discussed. Finally, challenges facing the clinical translation of nanoparticles from bench to bedside are highlighted.

Combinative effects of akarkara root-derived metabolites on anti-inflammatory and anti-alzheimer key enzymes: integrating bioassay-guided fractionation, GC-MS analysis, and in silico studies

BACKGROUND

Anacyclus pyrethrum L. (Akarkara root), a valuable Ayurvedic remedy, is reported to exhibit various pharmacological activities. Akarkara root was subjected to bioassay-guided fractionation, to isolate its active constituents and discover their potential bioactivities, followed by computational analysis.

METHODS

The methanol extract and its fractions, methylene chloride, and butanol, were assessed for their antioxidant, anti-inflammatory, and anticholinergic potentials. The antioxidant activity was determined using DPPH, ABTS, FRAP, and ORAC assays. The in vitro anticholinergic effect was evaluated via acetyl- and butyryl-cholinesterase inhibition, while anti-inflammatory effect weas determined using COX-2 and 5-LOX inhibitory assays. The methylene chloride fraction was subjected to GC/MS analysis and chromatographic fractionation to isolate its major compounds. The inhibitory effect on iNOS and various inflammatory mediators in LPS-activated RAW 264.7 macrophages was investigated. In silico computational analyses (molecular docking, ADME, BBB permeability prediction, and molecular dynamics) were performed.

RESULTS

Forty-one compounds were identified and quantified and the major compounds, namely, oleamide (A1), stigmasterol (A2), 2E,4E-deca-2,4-dienoic acid 2-phenylethyl amide (A3), and pellitorine (A4) were isolated from the methylene chloride fraction, the most active in all assays. All compounds showed significant in vitro antioxidant, anticholinergic and anti-inflammatory effects. They inhibited the secretion of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in activated RAW macrophages. The isolated compounds showed good fitting in the active sites of acetylcholinesterase and COX-2 with high docking scores. The ADME study revealed proper pharmacokinetics and drug likeness properties for the isolated compounds. The isolated compounds demonstrated high ability to cross the BBB and penetrate the CNS with values ranging from 1.596 to -1.651 in comparison with Donepezil (-1.464). Molecular dynamics simulation revealed stable conformations and binding patterns of the isolated compounds with the active sites of COX-2 and acetyl cholinesterase.

CONCLUSIONS

Ultimately, our results specify Akarkara compounds as promising candidates for the treatment of inflammatory and neurodegenerative diseases.

Role of GSK-3β Inhibitors: New Promises and Opportunities for Alzheimer's Disease

Glycogen synthase kinase-3 (GSK-3) was discovered to be a multifunctional enzyme involved in a wide variety of biological processes, including early embryo formation, oncogenesis, as well cell death in neurodegenerative diseases. Several critical cellular processes in the brain are regulated by the GSK-3β, serving as a central switch in the signaling pathways. Dysregulation of GSK-3β kinase has been reported in diabetes, cancer, Alzheimer's disease, schizophrenia, bipolar disorder, inflammation, and Huntington's disease. Thus, GSK-3β is widely regarded as a promising target for therapeutic use. The current review article focuses mainly on Alzheimer's disease, an age-related neurodegenerative brain disorder. GSK-3β activation increases amyloid-beta (Aβ) and the development of neurofibrillary tangles that are involved in the disruption of material transport between axons and dendrites. The drug-binding cavities of GSK-3β are explored, and different existing classes of GSK-3β inhibitors are explained in this review. Non-ATP competitive inhibitors, such as allosteric inhibitors, can reduce the side effects compared to ATP-competitive inhibitors. Whereas ATP-competitive inhibitors produce disarrangement of the cytoskeleton, neurofibrillary tangles formation, and lead to the death of neurons, etc. This could be because they are binding to a site separate from ATP. Owing to their interaction in particular and special binding sites, allosteric ligands interact with substrates more selectively, which will be beneficial in resolving drug-induced resistance and also helpful in reducing side effects. Hence, in this review, we focussed on the allosteric GSK-3β inhibitors and discussed their futuristic opportunities as anti-Alzheimer's compounds.

Mammalian Models in Alzheimer's Research: An Update

A form of dementia distinct from healthy cognitive aging, Alzheimer's disease (AD) is a complex multi-stage disease that currently afflicts over 50 million people worldwide. Unfortunately, previous therapeutic strategies developed from murine models emulating different aspects of AD pathogenesis were limited. Consequently, researchers are now developing models that express several aspects of pathogenesis that better reflect the clinical situation in humans. As such, this review seeks to provide insight regarding current applications of mammalian models in AD research by addressing recent developments and characterizations of prominent transgenic models and their contributions to pathogenesis as well as discuss the advantages, limitations, and application of emerging models that better capture genetic heterogeneity and mixed pathologies observed in the clinical situation.

β-Amyloid targeting nanodrug for neuron-specific delivery of nucleic acids in Alzheimer's disease mouse models

Delivery of therapeutic substances into the brain poses a significant challenge in the treatment of neurological disorders. This is primarily due to the blood-brain barrier (BBB), which restricts access, alongside the limited stability and distribution of these agents within the brain tissue. Here we demonstrate an efficient delivery of microRNA (miRNA) and antisense RNA preferentially to neurons compared to astroglia in the brain of healthy and Alzheimer's disease mice, via disulfide-linked conjugation with poly(ß-L-malic acid-trileucine)-copolymer a biodegradable, amphiphilic, and multivalent platform. By conjugating a D-configured (D3)-peptide (vector) for specific targeting, highly efficient delivery across the BBB is achieved through the Low-Density Lipoprotein Receptor-Related Protein-1 (LRP-1) transcytosis pathway, amyloid beta (Aβ) peptides. Nanodrug distribution was determined by fluorescent labeling and analyzed by microscopy in neurons, astroglia, and in extracellular amyloid plaques typical for Alzheimer's disease. Whereas D-configured BBB-vectors can efficiently target neurons, L-configured (e.g., AP2-peptide) guided vector can only cross BBB but not seem to bind neurons. An analysis of post-injection fluorescence distribution, and RNA-seq followed by real-time PCR validation, confirmed a successful in vivo delivery of morpholino-miRNA-186 nanoconjugates into mouse brain. The size and fluorescence intensity of the intracellular nanodrug particulates were analyzed and verified by a competition with non-fluorescent conjugates. Differentially expressed genes (DEGs) from RNA-seq were identified in the nanodrug injected mice, and the changes of selected DEGs related to Alzheimer's disease were further validated by western blot and real-time PCR. Collectively, these results demonstrated that D3-peptide-conjugated nanopolymer drug is able to achieve neuron-selective delivery of miRNA and can serve as an efficient brain delivery vehicle in Alzheimer's disease (AD) mouse models.

Cell membrane-based nanomaterials for theranostics of central nervous system diseases

Central nervous system (CNS) diseases have been widely acknowledged as one of the major healthy concerns globally, which lead to serious impacts on human health. There will be about 135 million CNS diseases cases worldwide by mid-century, and CNS diseases will become the second leading cause of death after the cardiovascular disease by 2040. Most CNS diseases lack of effective diagnostic and therapeutic strategies with one of the reasons that the biological barrier extremely hampers the delivery of theranostic agents. In recent years, nanotechnology-based drug delivery is a quite promising way for CNS diseases due to excellent properties. Among them, cell membrane-based nanomaterials with natural bio-surface, high biocompatibility and biosafety, are of great significance in both the diagnosis and treatment of different CNS diseases. In this review, the state of art of the fabrication of cell membranes-based nanomaterials is introduced. The characteristics of different CNS diseases, and the application of cell membranes-based nanomaterials in the theranostics are summarized. In addition, the future prospects and limitations of cell membrane nanotechnology are anticipated. Through summarizing the state of art of the fabrication, giving examples of CNS diseases, and highlighting the applications in theranostics, the current review provides designing methods and ideas for subsequent cell membrane nanomaterials.

The Potent and Selective Histamine H3 Receptor Antagonist E169 Counteracts Cognitive Deficits and Mitigates Disturbances in the PI3K/AKT/GSK-3β Signaling Pathway in MK801-Induced Amnesia in Mice

The role of histamine H3 receptors (H3Rs) in memory and the prospective of H3R antagonists in pharmacological control of neurodegenerative disorders, e.g., Alzheimer's disease (AD), is well-accepted. Therefore, the procognitive effects of acute systemic administration of H3R antagonist E169 (2.5-10 mg/kg, i.p.) on MK801-induced amnesia in C57BL/6J mice using the novel object recognition test (NORT) were evaluated. E169 (5 mg) provided a significant memory-improving effect on MK801-induced short- and long-term memory impairments in NORT. The E169 (5 mg)-provided effects were comparable to those observed with the reference phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and were abrogated with the H3R agonist (R)-α-methylhistamine (RAMH). Additionally, our results demonstrate that E169 ameliorated MK801-induced memory deficits by antagonism of H3Rs and by modulation of the level of disturbance in the expression of PI3K, Akt, and GSK-3β proteins, signifying that E169 mitigated the Akt-mTOR signaling pathway in the hippocampus of tested mice. Moreover, the results observed revealed that E169 (2.5-10 mg/kg, i.p.) did not alter anxiety levels and locomotor activity of animals in open field tests, demonstrating that performances improved following acute systemic administration with E169 in NORT are unrelated to changes in emotional response or in spontaneous locomotor activity. In summary, these obtained results suggest the potential of H3R antagonists such as E169, with good in silico physicochemical properties and stable retained key interactions in docking studies at H3R, in simultaneously modulating disturbed brain neurotransmitters and the imbalanced Akt-mTOR signaling pathway related to neurodegenerative disorders, e.g., AD.

Recent Advancements in Nanomaterials: A Promising Way to Manage Neurodegenerative Disorders

Neurodegenerative diseases (NDs) such as dementia, Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and amyotrophic lateral sclerosis are some of the most prevalent disorders currently afflicting healthcare systems. Many of these diseases share similar pathological hallmarks, including elevated oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation, all of which contribute to the deterioration of the nervous system's structure and function. The development of diagnostic and therapeutic materials in the monitoring and treatment of these diseases remains challenging. One of the biggest challenges facing therapeutic and diagnostic materials is the blood-brain barrier (BBB). The BBB is a multifunctional membrane possessing a plethora of biochemical, cellular, and immunological features that ensure brain homeostasis by preventing the entry and accumulation of unwanted compounds. With regards to neurodegenerative diseases, the recent application of tailored nanomaterials (nanocarriers and nanoparticles) has led to advances in diagnostics and therapeutics. In this review, we provide an overview of commonly used nanoparticles and their applications in NDs, which may offer new therapeutic strategies for the prevention and treatment of neurodegenerative diseases.

Synthesis of mannan oligosaccharide-sialic acid conjugates and its inhibition on Aβ42 aggregation

In this work, a mannan-oligosaccharide conjugate with sialic acid capable of perturbing Aβ42 aggregation was designed and synthesized. Mannan oligosaccharides with degree polymerization of 3-13 were obtained by stepwise hydrolysis of locust bean gum using β-mannanase and α-galactosidase, named as LBOS. The activated LBOS was further chemically conjugated with sialic acid (Sia, N-acetylneuraminic acid) by fluoro-mercapto chemical coupling to synthesize a conjugate LBOS-Sia, and then phosphorylated to obtain pLBOS-Sia. The successful synthesis of pLBOS-Sia was confirmed by infrared1 chromatography, mass spectrometry, and ¹H NMR. The soluble protein analysis, microscopic observation, thioflavin T-labeling, and circular dichroism spectroscopy revealed that both LBOS-Sia and pLBOS-Sia can inhibit Aβ42 aggregation. MTT assay showed that LBOS-Sia and pLBOS-Sia had no cytotoxicity to BV-2 cells, and could substantially reduce the release of pro-inflammatory factor TNF-α induced by Aβ42 in BV-2 cells, and inhibit the occurrence of neuroinflammation. In future, this novel structure of mannan oligosaccharide-sialic acid conjugate can be potentially used to for the development of glycoconjugates against AD targeting Aβ.

An Alzheimer's disease category progression sub-grouping analysis using manifold learning on ADNI

Many current statistical and machine learning methods have been used to explore Alzheimer's disease (AD) and its associated patterns that contribute to the disease. However, there has been limited success in understanding the relationship between cognitive tests, biomarker data, and patient AD category progressions. In this work, we perform exploratory data analysis of AD health record data by analyzing various learned lower dimensional manifolds to separate early-stage AD categories further. Specifically, we used Spectral embedding, Multidimensional scaling, Isomap, t-Distributed Stochastic Neighbour Embedding, Uniform Manifold Approximation and Projection, and sparse denoising autoencoder based manifolds on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. We then determine the clustering potential of the learned embeddings and then determine if category sub-groupings or sub-categories can be found. We then used a Kruskal-sWallis H test to determine the statistical significance of the discovered AD subcategories. Our results show that the existing AD categories do exhibit sub-groupings, especially in mild cognitive impairment transitions in many of the tested manifolds, showing there may be a need for further subcategories to describe AD progression.

Effects of gut microbiota on neurodegenerative diseases

A progressive degradation of the brain's structure and function, which results in a reduction in cognitive and motor skills, characterizes neurodegenerative diseases (NDs) such as Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). The morbidity linked to NDs is growing, which poses a severe threat to human being's mental and physical ability to live well. The gut-brain axis (GBA) is now known to have a crucial role in the emergence of NDs. The gut microbiota is a conduit for the GBA, a two-way communication system between the gut and the brain. The myriad microorganisms that make up the gut microbiota can affect brain physiology by transmitting numerous microbial chemicals from the gut to the brain via the GBA or neurological system. The synthesis of neurotransmitters, the immunological response, and the metabolism of lipids and glucose have all been demonstrated to be impacted by alterations in the gut microbiota, such as an imbalance of helpful and harmful bacteria. In order to develop innovative interventions and clinical therapies for NDs, it is crucial to comprehend the participation of the gut microbiota in these conditions. In addition to using antibiotics and other drugs to target particular bacterial species that may be a factor in NDs, this also includes using probiotics and other fecal microbiota transplantation to maintain a healthy gut microbiota. In conclusion, the examination of the GBA can aid in understanding the etiology and development of NDs, which may benefit the improvement of clinical treatments for these disorders and ND interventions. This review indicates existing knowledge about the involvement of microbiota present in the gut in NDs and potential treatment options.

The Adult Neurogenesis Theory of Alzheimer's Disease

Alzheimer's disease starts in neural stem cells (NSCs) in the niches of adult neurogenesis. All primary factors responsible for pathological tau hyperphosphorylation are inherent to adult neurogenesis and migration. However, when amyloid pathology is present, it strongly amplifies tau pathogenesis. Indeed, the progressive accumulation of extracellular amyloid-β deposits in the brain triggers a state of chronic inflammation by microglia. Microglial activation has a significant pro-neurogenic effect that fosters the process of adult neurogenesis and supports neuronal migration. Unfortunately, this "reactive" pro-neurogenic activity ultimately perturbs homeostatic equilibrium in the niches of adult neurogenesis by amplifying tau pathogenesis in AD. This scenario involves NSCs in the subgranular zone of the hippocampal dentate gyrus in late-onset AD (LOAD) and NSCs in the ventricular-subventricular zone along the lateral ventricles in early-onset AD (EOAD), including familial AD (FAD). Neuroblasts carrying the initial seed of tau pathology travel throughout the brain via neuronal migration driven by complex signals and convey the disease from the niches of adult neurogenesis to near (LOAD) or distant (EOAD) brain regions. In these locations, or in close proximity, a focus of degeneration begins to develop. Then, tau pathology spreads from the initial foci to large neuronal networks along neural connections through neuron-to-neuron transmission.

A Brief Overview of Neutrophils in Neurological Diseases

Neutrophils are the most abundant leukocyte in circulation and are the first line of defense after an infection or injury. Neutrophils have a broad spectrum of functions, including phagocytosis of microorganisms, the release of pro-inflammatory cytokines and chemokines, oxidative burst, and the formation of neutrophil extracellular traps. Traditionally, neutrophils were thought to be most important for acute inflammatory responses, with a short half-life and a more static response to infections and injury. However, this view has changed in recent years showing neutrophil heterogeneity and dynamics, indicating a much more regulated and flexible response. Here we will discuss the role of neutrophils in aging and neurological disorders; specifically, we focus on recent data indicating the impact of neutrophils in chronic inflammatory processes and their contribution to neurological diseases. Lastly, we aim to conclude that reactive neutrophils directly contribute to increased vascular inflammation and age-related diseases.

Vascular Dysfunction in Alzheimer's Disease: Alterations in the Plasma Contact and Fibrinolytic Systems

Alzheimer's disease (AD) is the most common neurodegenerative disease, affecting millions of people worldwide. The classical hallmarks of AD include extracellular beta-amyloid (Aβ) plaques and neurofibrillary tau tangles, although they are often accompanied by various vascular defects. These changes include damage to the vasculature, a decrease in cerebral blood flow, and accumulation of Aβ along vessels, among others. Vascular dysfunction begins early in disease pathogenesis and may contribute to disease progression and cognitive dysfunction. In addition, patients with AD exhibit alterations in the plasma contact system and the fibrinolytic system, two pathways in the blood that regulate clotting and inflammation. Here, we explain the clinical manifestations of vascular deficits in AD. Further, we describe how changes in plasma contact activation and the fibrinolytic system may contribute to vascular dysfunction, inflammation, coagulation, and cognitive impairment in AD. Given this evidence, we propose novel therapies that may, alone or in combination, ameliorate AD progression in patients.

IL-6 Enhances the Negative Impact of Cortisol on Cognition among Community-Dwelling Older People without Dementia

There is growing evidence that high basal cortisol levels and systemic inflammation independently contribute to cognitive decline among older people without dementia. The present cross-sectional study examined (a) the potential synergistic effect of cortisol levels and systemic inflammation on executive function and (b) whether this effect is more prominent among older people with mild cognitive impairment (MCI). A sub-sample of 99 patients with MCI and 84 older people without cognitive impairment (CNI) (aged 73.8 ± 7.0 years) were recruited from a large population-based cohort in Crete, Greece, and underwent comprehensive neuropsychiatric and neuropsychological evaluation and a single morning measurement of cortisol and IL-6 plasma levels. Using moderated regression models, we found that the relation between cortisol and executive function in the total sample was moderated by IL-6 levels (b = −0.994, p = 0.044) and diagnostic group separately (b = −0.632, p < 0.001). Moreover, the interaction between cortisol and IL-6 levels was significant only among persons with MCI (b = −0.562, p < 0.001). The synergistic effect of stress hormones and systemic inflammation on cognitive status appears to be stronger among older people who already display signs of cognitive decline. Targeting hypercortisolemia and inflammation may be a promising strategy toward improving the course of cognitive decline.

Protective Effects of Cannabis in Neuroinflammation-Mediated Alzheimer's Disease

In recent years, Alzheimer's disease (AD) has been recognized as an age-related neurological disorder wherein neurons degenerate and exhibit abnormal structure and function. Aging is the primary factor in the progression of AD from mild to severe cognitive impairment. No effective targeted therapies are presently available, and treatment is limited to symptomatic management. The neuropathologic hallmarks of the disease include the accumulation of amyloid-beta (Aβ) plaques in brain tissues and the aggregation of hyperphosphorylated-tau proteins (tangles) within neurons. Associated hyperactivation of neuroinflammation results in release of inflammatory molecules from neurons, microglia, and astrocytes, which have been linked with neuronal loss and the worsening neurodegeneration. The anti-inflammatory and neuroprotective properties of cannabis-based medicines may offer benefits in delaying the progression of neurodegenerative diseases including AD. This chapter explores the role of cannabinoids in countering neuroinflammation-mediated AD pathology.

Effect of acupuncture on neuroinflammation in animal models of Alzheimer's disease: A preclinical systematic review and meta-analysis

Background

Despite neuroinflammation being an important component of the pathology of Alzheimer's disease (AD), effective therapies to alleviate neuroinflammation are still lacking. Many animal experiments in AD have found that acupuncture may ameliorate cognition by decreasing neuroinflammation and modulating cytokines, but its effects have not been systematically examined. We aimed to assess its efficacy on neuroinflammation in AD and to investigate the potential mechanisms.

Materials and methods

The following databases were searched from inception until 24 August 2022: Web of Science, EMBASE, PubMed, the Cochrane Library, and China National Knowledge Infrastructure. Animal studies that reported the efficacy of acupuncture on neuroinflammation in AD were included. The SYRCLE Robt was utilized to evaluate methodological quality. Stata 17 was utilized to conduct a meta-analysis of cytokine levels and the results of the Morris water maze.

Results

23 studies were included, with a total of 417 rats/mice. The overall quality of all included reports was medium. The results indicated that acupuncture significantly reduced the expressions of pro-inflammatory cytokines which included IL-1β [SMD = -3.50, 95% CI (-4.31, -2.69); I 2 = 78.6%] (P < 0.05), TNF-α [SMD = -3.05, 95% CI (-3.86, -2.24); I 2 = 69.6%] (P < 0.05), IL-6 [SMD = -3.22, 95% CI (-4.62, -1.81); I 2 = 77.6%] and enhanced the expressions of anti-inflammatory cytokines including IL-4 [SMD = 2.77, 95% CI (1.95, 3.59); I 2 = 33.9%] (P < 0.05), IL-10 [SMD = 1.84, 95% CI (1.20, 2.49); I 2 = 41.0%] (P < 0.05) in an animal model of AD. Regarding the Morris water maze, compared to the control group, the acupuncture group showed a shorter escape latency [SMD = -2.23, 95% CI (-2.89, -1.57); I 2 = 79.2%] (P < 0.05), longer duration in platform quadrant [SMD = 2.34, 95% CI (1.44, 3.23); I 2 = 81.7%] (P < 0.05), and increased platform crossing number [SMD = 2.79, 95% CI (2.06, 3.53); I 2 = 71.9%] (P < 0.05).

Conclusion

Acupuncture may reduce neuroinflammation in AD by modulating cytokine expression. This modulation significantly improved cognitive function in animal models of AD.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022354878.

Phenylethanoid Glycosides of Cistanche Improve Learning and Memory Disorders in APP/PS1 Mice by Regulating Glial Cell Activation and Inhibiting TLR4/NF-κB Signaling Pathway

Phenylethanoid Glycosides of Cistanche (PhGs) have a certain curative effect on AD animal model, Echinacea (ECH) and verbascoside (ACT), as the quality control standard of Cistanche deserticola Y. C. Ma and the main representative compounds of PhGs have been proved to have neuroprotective effects, but the specific mechanism needs to be further explored. This study explored the mechanisms of PhGs, ECH, and ACT in the treatment of Alzheimer's disease (AD) from the perspectives of glial cell activation, TLR4/NF-κB signaling pathway, and synaptic protein expression. We used APP/PS1 mice as AD models. After treatment with PhGs, ECH, and ACT, the learning and memory abilities of APP/PS1 mice were enhanced, and the pathological changes in brain tissue were alleviated. The expression of pro-inflammatory M1 microglia markers (CD11b, iNOS, and IL-1β) was decreased; the expression of M2 microglia markers (Arg-1 and TGF-β1) was increased, which promoted the transformation of microglia from M1 pro-inflammatory phenotype to M2 anti-inflammatory phenotype. In addition, PhGs, ECH, and ACT could down-regulate the expression of proteins related to the TLR4/NF-κB signaling pathway and up-regulate the expression of synaptic proteins. The results indicated that PhGs, ECH, and ACT played a neuroprotective role by regulating the activation of glial cells and inhibiting the TLR4/NF-κB inflammatory pathway, and improving the expression levels of synapse-related proteins.

Aqueous extract of Ceratonia siliqua L. leaves elicits antioxidant, anti-inflammatory, and AChE inhibiting effects in amyloid-β42-induced cognitive deficit mice: Role of α7-nAChR in modulating Jak2/PI3K/Akt/GSK-3β/β-catenin cascade

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder attributed to several etiological factors including cholinergic dysregulation, neuroinflammation, oxidative stress, β-amyloidogenesis, and tauopathy. This demands the search for multitarget drugs, especially of natural sources owing to their pleiotropic activities and low adverse effects. The present study was conducted to investigate the cognitive-improving potential of Ceratonia siliqua L. (Cs) extract compared with donepezil, an acetylcholinesterase inhibitor, on AD-like pathological alterations induced by single intracerebroventricular amyloid-β42 (Aβ42) injection in mice. Aβ42-injected mice were treated with Cs (100 mg/kg/day, po) with or without methyllycaconitine (MLA; 1 mg/kg/day, ip), an α7-nAChR antagonist. Aβ42-injected animals demonstrated an elevation of hippocampal Aβ42, p-Tau, and acetylcholinesterase. They also showed a decline in phosphorylated levels of Jak2, PI3K, Akt, and GSK-3β, leading to induction of neuroinflammation and oxidative stress. Noteworthy, Cs improved the histopathological and behavioral variables in addition to mitigating AD hallmarks. It also exerted neuroprotection by reducing NF-κBp65 and TNF-α, while elevating Nrf2 and HO-1, along with stabilizing β-catenin under the impact of Jak2/PI3K/Akt/GSK-3β signaling. These beneficial effects of Cs were abrogated by MLA co-administration signifying the α7-nAChR involvement in Cs-mediated effects. Therefore, Cs can ameliorate Aβ42-induced neurodegeneration by modulating Jak2/PI3K/Akt/GSK-3β/β-catenin axis in an α7-nAChR-dependent manner.

A role for flavonoids in the prevention and/or treatment of cognitive dysfunction, learning, and memory deficits: a review of preclinical and clinical studies

OBJECTIVE

Natural food substances, due to high rates of antioxidants, antiviral and anti-inflammatory properties, have been proposed to have the potential for the prevention or treatment of cognitive deficits, learning and memory deficits and neuro inflammation. In particular, medicinal plants with rich amounts of beneficial components such as flavonoids are one of the most promising therapeutic candidates for the cognitive deficit and memory loss. Herein, we aimed to review the impact of medicinal plants with focus on flavonoids on cognitive dysfunction, learning and memory loss by considering their signaling pathways.

METHODS

We extracted 93 preclinical and clinical studies related to the effects of flavonoids on learning and memory and cognition from published papers between 2000 and 2021 in the MEDLINE/PubMed, Cochrane Library, SCOPUS, and Airiti Library databases.

RESULTS

In the preclinical studies, at least there seem to be two main neurological and biological processes in which flavonoids contribute to the improvement and/or prevention of learning, memory deficit and cognitive dysfunction: (1) Regulation of neurotransmission system and (2) Enhancement of neurogenesis, synaptic plasticity and neuronal survival.

CONCLUSION

Although useful effects of flavonoids on learning and memory in preclinical investigations have been approved, more clinical trials are required to find out whether flavonoids and/or other ingredients of plants have the potent to prevent or treat neurodegenerative disorders.

Stem Cell-derived Extracellular Vesicles: A Promising Nano Delivery Platform to the Brain?

A very important cause of the frustration with drug therapy for central nervous system (CNS) diseases is the failure of drug delivery. The blood-brain barrier (BBB) prevents most therapeutic molecules from entering the brain while maintaining CNS homeostasis. Scientists are keen to develop new brain drug delivery systems to solve this dilemma. Extracellular vesicles (EVs), as a class of naturally derived nanoscale vesicles, have been extensively studied in drug delivery due to their superior properties. This review will briefly present current brain drug delivery strategies, including invasive and non-invasive techniques that target the brain, and the application of nanocarriers developed for brain drug delivery in recent years, especially EVs. The cellular origin of EVs affects the surface protein, size, yield, luminal composition, and other properties of EVs, which are also crucial in determining whether EVs are useful as drug carriers. Stem cell-derived EVs, which inherit the properties of parental cells and avoid the drawbacks of cell therapy, have always been favored by researchers. Thus, in this review, we will focus on the application of stem cell-derived EVs for drug delivery in the CNS. Various nucleic acids, proteins, and small-molecule drugs are loaded into EVs with or without modification and undergo targeted delivery to the brain to achieve their therapeutic effects. In addition, the challenges facing the clinical application of EVs as drug carriers will also be discussed. The directions of future efforts may be to improve drug loading efficiency and precise targeting.

Cortical-blood vessel assembloids exhibit Alzheimer's disease phenotypes by activating glia after SARS-CoV-2 infection

A correlation between COVID-19 and Alzheimer's disease (AD) has been proposed recently. Although the number of case reports on neuroinflammation in COVID-19 patients has increased, studies of SARS-CoV-2 neurotrophic pathology using brain organoids have restricted recapitulation of those phenotypes due to insufficiency of immune cells and absence of vasculature. Cerebral pericytes and endothelial cells, the major components of blood-brain barrier, express viral entry receptors for SARS-CoV-2 and response to systemic inflammation including direct cell death. To overcome the limitations, we developed cortical-blood vessel assembloids by fusing cortical organoid with blood vessel organoid to provide vasculature to brain organoids a nd obtained the characteristics of increased expression of microglia and astrocytes in brain organoids. Furthermore, we observed AD pathologies, including β-amyloid plaques, which were affected by the inflammatory response from SARS-CoV-2 infection. These findings provide an advanced platform to investigate human neurotrophic diseases, including COVID-19, and suggest that neuroinflammation caused by viral infection facilitates AD pathology.

Effects of Current Psychotropic Drugs on Inflammation and Immune System

The immune system and inflammation are involved in the pathological progression of various psychiatric disorders such as depression or major depressive disorder (MDD), generalized anxiety disorder (GAD) or anxiety, schizophrenia, Alzheimer's disease (AD), and Huntington's disease. It is observed that levels of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and other markers are highly increased in the abovementioned disorders. The inflammation and immune component also lead to enhance the oxidative stress. The oxidative stress and increased production of reactive oxygen species (ROS) are considered as important factors that are involved in pathological progression of psychiatric disorders. Increase production of ROS is associated with excessive inflammation followed by cell necrosis and death. The psychotropic drugs are mainly work through modulations of neurotransmitter system. However, it is evident that inflammation and immune modulation are also having important role in the progression of psychiatric disorders. Rationale of the use of current psychotropic drugs is modulation of immune system by them. However, the effects of psychotropic drugs on the immune system and how these might contribute to their efficacy remain largely unclear. The drugs may act through modification of inflammation and related markers. The main purpose of this book chapter is to address the role of current psychotropic drugs on inflammation and immune system. Moreover, it will also address the role of inflammation in the progression of psychiatric disorders.

The Microbiome-Gut-Brain Axis and Dementia: A Bibliometric Analysis

BACKGROUND

Associations between the microbiome-gut-brain axis and dementia have attracted considerable attention in research literature. This study examined the microbiome-gut-brain axis and dementia-related research from a bibliometric perspective.

METHODS

A search for original research and review articles on the microbiome-gut-brain axis and dementia was conducted in the Web of Science Core Collection (WOSCC) database. The R package "bibliometrix" was used to collect information on countries, institutions, authors, journals, and keywords. VOSviewer software was used to visualize the co-occurrence network of keywords.

RESULTS

Overall, 494 articles met the study inclusion criteria, with an average of 29.64 citations per article. Corresponding authors of published articles were mainly from China, the United States and Italy. Zhejiang University in China and Kyung Hee University in Korea were the most active institutions, while the Journal of Alzheimer's Disease and Nutrients published the most articles in this field. Expected main search terms, "Parkinson disease" and "chain fatty-acids" were high-frequency keywords that indicate current and future research directions in this field.

CONCLUSIONS

This bibliometric study helped researchers to identify the key topics and trends in the microbiome-gut-brain axis and dementia-related research. High-frequency keywords identified in this study reflect current trends and possible future directions in this field related to methodologies, mechanisms and populations of interest.

Isolation of Phenolic Compounds from Raspberry Based on Molecular Imprinting Techniques and Investigation of Their Anti-Alzheimer's Disease Properties

Alzheimer's disease is the most common neurodegenerative disease, characterized by memory loss and cognitive dysfunction. Raspberry fruits contain polyphenols which have antioxidant and anti-inflammatory properties. In this study, we used molecular imprinting technology to efficiently isolate phenolic components from the raspberry ethyl acetate extracts. Six phenolic components (ellagic acid, tiliroside, kaempferol-3-o-rutoside, gallic acid, ferulic acid and vanillic acid) were identified by UPLC-Q-TOF-MS analysis. Molecular docking was used to predict the anti-inflammatory effects and anti-Alzheimer's potential of these isolated compounds, which showed a good binding ability to diseases and related proteins. However, the binding energy and docking fraction of ellagic acid, tiliroside, and kaempferol-3-o-rutoside were better than those of gallic acid, ferulic acid and vanillic acid. Additionally, by studying the effects of these six phenolic components on the LPS-induced secretion of inflammatory mediators in murine microglial (BV2) cells, it was further demonstrated that they were all capable of inhibiting the secretion of NO, IL-6, TNF-α, and IL-1β to a certain extent. However, ellagic acid, tiliroside, and kaempferol-3-o-rutoside have better inhibitory effects compared to others. The results obtained suggest that the phenolic components extracted from ethyl acetate extracts of raspberry by molecularly imprinted polymers have the potential to inhibit the progression of Alzheimer's disease.

Probiotics Treatment Can Improve Cognition in Patients with Mild Cognitive Impairment: A Systematic Review

Background: In recent years, the existence of the gut-brain axis and the impact of intestinal microbiota on brain function has received much attention. Accumulated evidence has prompted the postulation of the infectious hypothesis underlying or facilitating neurodegenerative diseases, such as Alzheimer’s disease. Under this hypothesis, intervention with probiotics could be useful at a preventive and therapeutic level. Objective: The objective of this systematic review is to reveal a benefit of improved cognitive function following the use of probiotics in individuals with mild cognitive impairment. Methods: We searched bibliographic databases and analyzed in detail the evidence and methodological quality of five recent randomized, double-blind, placebo-controlled clinical trials using the Cochrane Tool and the SIGN checklist. Results: Overall, and with satisfactory methodological quality, the studies evaluated support the use of probiotics as a weapon to slow the progression of cognitive decline in subjects with mild cognitive impairment. The literature review also indicates that maximum benefit of probiotics is found in subjects with incipient cognitive dysfunction and has no effect in those with advanced disease or absence of disease. Conclusion: These results support the intervention with probiotics, especially as a preventive approach. However, caution is required in the interpretation of the results as microbiota has not been evaluated in all studies, and further large-scale research with a prolonged study period is necessary to ensure the translatability of the results into real practice.

Signature Effects of Vector-Guided Systemic Nano Bioconjugate Delivery Across Blood-Brain Barrier of Normal, Alzheimer's, and Tumor Mouse Models

The ability to cross the blood-brain barrier (BBB) is critical for targeted therapy of the central nerve system (CNS). Six peptide vectors were covalently attached to a 50 kDa poly(β-l-malic acid)-trileucine polymer forming P/LLL(40%)/vector conjugates. The vectors were Angiopep-2 (AP2), B6, Miniap-4 (M4), and d-configurated peptides D1, D3, and ACI-89, with specificity for transcytosis receptors low-density lipoprotein receptor-related protein-1 (LRP-1), transferrin receptor (TfR), bee venom-derived ion channel, and Aβ/LRP-1 related transcytosis complex, respectively. The BBB-permeation efficacies were substantially increased ("boosted") in vector conjugates of P/LLL(40%). We have found that the copolymer group binds at the endothelial membrane and, by an allosterically membrane rearrangement, exposes the sites for vector-receptor complex formation. The specificity of vectors is indicated by competition experiments with nonconjugated vectors. P/LLL(40%) does not function as an inhibitor, suggesting that the copolymer binding site is eliminated after binding of the vector-nanoconjugate. The two-step mechanism, binding to endothelial membrane and allosteric exposure of transcytosis receptors, is supposed to be an integral feature of nanoconjugate-transcytosis pathways. In vivo brain delivery signatures of the nanoconjugates were recapitulated in mouse brains of normal, tumor (glioblastoma), and Alzheimer's disease (AD) models. BBB permeation of the tumor was most efficient, followed by normal and then AD-like brain. In tumor-bearing and normal brains, AP2 was the top performing vector; however, in AD models, D3 and D1 peptides were superior ones. The TfR vector B6 was equally efficient in normal and AD-model brains. Cross-permeation efficacies are manifested through modulated vector coligation and dosage escalation such as supra-linear dose dependence and crossover transcytosis activities.