Molecular Mechanisms of Neuroinflammation in Aging and Alzheimer's Disease Progression

Tau proteins and senescent Cells: Targeting aging pathways in Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disease characterized by abnormal accumulation of tau proteins and amyloid-β, leading to neuronal death and cognitive impairment. Recent studies have implicated aging pathways, including dysregulation of tau and cellular senescence in AD pathogenesis. In AD brains, tau protein, which normally stabilizes microtubules, becomes hyperphosphorylated and forms insoluble neurofibrillary tangles. These tau aggregates impair neuronal function and are propagated across the brain's neurocircuitry. Meanwhile, the number of senescent cells accumulating in the aging brain is rising, releasing a pro-inflammatory SASP responsible for neuroinflammation and neurodegeneration. This review explores potential therapeutic interventions for AD targeting tau protein and senescent cells, and tau -directed compounds, senolytics, eliminating senescent cells, and agents that modulate the SASP-senomodulators. Ultimately, a combined approach that incorporates tau-directed medications and targeted senescent cell-based therapies holds promise for reducing the harmful impact of AD's shared aging pathways.

Alzheimer Disease as a Clinical-Biological Construct-An International Working Group Recommendation

Importance

Since 2018, a movement has emerged to define Alzheimer disease (AD) as a purely biological entity based on biomarker findings. The recent revision of the Alzheimer Association (AA) criteria for AD furthers this direction. However, concerns about a purely biological definition of AD being applied clinically, the understanding of AD by society at large, and the translation of blood-based biomarkers into clinical practice prompt these International Working Group (IWG) updated recommendations.

Objective

To consider the revised AA criteria and to offer an alternative definitional view of AD as a clinical-biological construct for clinical use. The recommendations of the 2021 IWG diagnostic criteria are updated for further elaborating at-risk and presymptomatic states.

Evidence Review

PubMed was searched for articles published between July 1, 2020, and March 1, 2024, using the terms "biomarker" OR "amyloid" OR "tau" OR "neurodegeneration" OR "preclinical" OR "CSF" OR "PET" OR "plasma" AND "Alzheimer's disease." The references of relevant articles were also searched.

Findings

In the new AA diagnostic criteria, AD can be defined clinically as encompassing cognitively normal people having a core 1 AD biomarker. However, recent literature shows that the majority of biomarker-positive cognitively normal individuals will not become symptomatic along a proximate timeline. In the clinical setting, disclosing a diagnosis of AD to cognitively normal people with only core 1 AD biomarkers represents the most problematic implication of a purely biological definition of the disease.

Conclusions and Relevance

The ultimate aim of the field was to foster effective AD treatments, including preventing symptoms and dementia. The approach of diagnosing AD without a clinical and biological construct would be unwarranted and potentially concerning without a clear knowledge of when or whether symptoms will ever develop. It is recommended that those who are amyloid-positive only and, more generally, most biomarker-positive cognitively normal individuals, should not be labeled as having AD. Rather, they should be considered as being at risk for AD. The expansion of presymptomatic AD is viewed as a better diagnostic construct for those with a specific pattern of biomarkers, indicating that they are proximate to the expression of symptoms in the near future.

Taxus chinensis (Pilg.) Rehder fruit attenuates aging behaviors and neuroinflammation by inhibiting microglia activation via TLR4/NF-κB/NLRP3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

As one of the important by-products of Taxus chinensis (Pilg.) Rehder, its fruit (TCF) has a sweet taste, which is commonly used in folklore to make health care wine reputed for enhancing immune function and promoting anti-aging effects, especially popular in the longevity villages of China for a long history. Evidences had showed that Taxus chinensis fruit contained polysaccharides, flavonoids, amino acids and terpenoids, which all were free of toxic compounds, but its medicinal value has not been fully recognized. Our previous studies have found that TCF extract may reverse many biological events, including oxidative stress, inflammatory response, neuronal apoptosis, etc. by in silico methods, suggesting potential avenues for future pharmaceutical exploration in aging and age-related diseases.

AIM OF THE STUDY

Yet, the anti-aging properties of TCF have not been specifically studied, this study aims to fill this gap by investigating the effects of TCF extract (TCFE) in an aging mouse model, particularly focusing on its role in inhibiting microglial activation and elucidating its underlying anti-aging mechanisms.

MATERIALS AND METHODS

An aging mouse model was induced using D-galactose, with interventions involving high, medium, and low doses of TCFE compared to a positive control (2 mg/kg rapamycin combined with 100 mg/kg metformin). The methodology involved evaluating behavioral changes, serum oxidative and antioxidative markers, hypothalamic β-galactosidase activity, expression of the aging-related protein P63, serum inflammatory factors, and the TLR4/NF-κB/NLRP3 inflammatory pathway in hypothalamic tissues. Additionally, to strengthen our in vivo findings, we conducted in vitro experiments on LPS-stimulated BV2 microglial cells. Finally, UPLC-MS/MS for precise component analysis using compound standards, coupled with molecular docking analyses, were employed to discern and elucidate the anti-inflammatory mechanisms of TCF.

RESULTS

In vivo results revealed TCFE significantly ameliorated behavioral deficits, reduced oxidative stress markers (MDA) and pro-inflammatory cytokines (IL1-β, IL-6, IFNg, TNFα, IL-17), and increased in antioxidants (SOD, T-AOC) and anti-inflammatory factors (IL-10). TCFE also reduced hypothalamic senescence, improved cellular integrity, lowered p63, and inhibited microglia activation and inflammatory pathways (TLR4, NFKB, NLRP3). The overall effect of TCFE was better than that of the positive drug group (rapamycin combined with metformin). In vitro results further revealed that TCFE markedly decreased IL1-β, NFKB, and TLR4 levels in BV2 microglial cells, showing comparable efficacy to a TLR4 classic positive inhibitor C34, supporting its anti-inflammatory role. Through UPLC-MS/MS analysis coupled with compound standards, we identified ten bioactive compounds, including gallocatechin, epigallocatechin, catechin, procyanidin B2, kaempferol, quercetin, rutin, naringin, apigenin, ginkgetin. All these compounds showed strong binding affinity to TLR4, notably procyanidin B2 and rutin, potentially through hydrogen bonds, aromatic cation-π interactions, and hydrophobic interactions, suggesting a molecular basis for their anti-inflammatory action.

CONCLUSION

TCFE showed strong anti-aging effects by inhibiting microglia activation and lessening oxidative stress and modulating inflammatory pathways. This research supports TCF's use in anti-aging and sets a base for future drug development in the realms of neuroinflammation and aging.

Role and Function of Peroxisomes in Neuroinflammation

Peroxisomes are organelles involved in many cellular metabolic functions, including the degradation of very-long-chain fatty acids (VLCFAs; C ≥ 22), the initiation of ether-phospholipid synthesis, and the metabolism of reactive oxygen species. All of these processes are essential for the maintenance of cellular lipid and redox homeostasis, and their perturbation can trigger inflammatory response in immune cells, including in the central nervous system (CNS) resident microglia and astrocytes. Consistently, peroxisomal disorders, a group of congenital diseases caused by a block in peroxisomal biogenesis or the impairment of one of the peroxisomal enzymes, are associated with neuroinflammation. Peroxisomal function is also dysregulated in many neurodegenerative diseases and during brain aging, both of which are associated with neuroinflammation. This suggests that deciphering the role of peroxisomes in neuroinflammation may be important for understanding both congenital and age-related brain dysfunction. In this review, we discuss the current advances in understanding the role and function of peroxisomes in neuroinflammation.

Inflammaging and Brain Aging

Progress made by the medical community in increasing lifespans comes with the costs of increasing the incidence and prevalence of age-related diseases, neurodegenerative ones included. Aging is associated with a series of morphological changes at the tissue and cellular levels in the brain, as well as impairments in signaling pathways and gene transcription, which lead to synaptic dysfunction and cognitive decline. Although we are not able to pinpoint the exact differences between healthy aging and neurodegeneration, research increasingly highlights the involvement of neuroinflammation and chronic systemic inflammation (inflammaging) in the development of age-associated impairments via a series of pathogenic cascades, triggered by dysfunctions of the circadian clock, gut dysbiosis, immunosenescence, or impaired cholinergic signaling. In addition, gender differences in the susceptibility and course of neurodegeneration that appear to be mediated by glial cells emphasize the need for future research in this area and an individualized therapeutic approach. Although rejuvenation research is still in its very early infancy, accumulated knowledge on the various signaling pathways involved in promoting cellular senescence opens the perspective of interfering with these pathways and preventing or delaying senescence.

A Systematic Review of Sporadic Creutzfeldt-Jakob Disease: Pathogenesis, Diagnosis, and Therapeutic Attempts

Creutzfeldt-Jakob disease is a rare neurodegenerative and invariably fatal disease with a fulminant course once the first clinical symptoms emerge. Its incidence appears to be rising, although the increasing figures may be related to the improved diagnostic tools. Due to the highly variable clinical picture at onset, many specialty physicians should be aware of this disease and refer the patient to a neurologist for complete evaluation. The diagnostic criteria have been changed based on the considerable progress made in research on the pathogenesis and on the identification of reliable biomarkers. Moreover, accumulated knowledge on pathogenesis led to the identification of a series of possible therapeutic targets, although, given the low incidence and very rapid course, the evaluation of safety and efficacy of these therapeutic strategies is challenging.

Neuroprotective Action of Selected Natural Drugs Against Neurological Diseases and Mental Disorders: Potential Use Against Radiation Damage

Exposure to radiation, ionizing and non-ionizing radiation, is a significant concern in modern society. The brain is the organ that is most sensitive to radiation exposure. This review describes how exposure to radiation can affect neurotransmitters in different brain regions, affecting brain function. This review covers neurodegenerative diseases such as Alzheimer's, Parkinson's, and neuroinflammation due to changes in neurons in the central nervous system, and the effects thereon of medicinal plants such as Allium cepa, Allium sativum, Centella asiatica, Coriandrum sativum, and Crocus sativus plants, used for centuries in traditional medicine. These herbal medicines exert free radical scavenging, and antioxidant as well as anti-inflammatory properties which can be beneficial in managing neurological diseases. The present review compiles the neuroprotective effects of selected natural plants against neurological damage, as well as highlights the different mechanisms of action elicited to induce and produce beneficial effects. The current review describes recent studies on the pharmacological effects of neuroprotective herbs on various neurological and mental illnesses, and shows the way further studies can impact this field, including potential effects on radiation-induced damage.

Unraveling mitochondrial dysfunction: comprehensive perspectives on its impact on neurodegenerative diseases

Neurodegenerative diseases represent a significant challenge to modern medicine, with their complex etiology and progressive nature posing hurdles to effective treatment strategies. Among the various contributing factors, mitochondrial dysfunction has emerged as a pivotal player in the pathogenesis of several neurodegenerative disorders. This review paper provides a comprehensive overview of how mitochondrial impairment contributes to the development of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, driven by bioenergetic defects, biogenesis impairment, alterations in mitochondrial dynamics (such as fusion or fission), disruptions in calcium buffering, lipid metabolism dysregulation and mitophagy dysfunction. It also covers current therapeutic interventions targeting mitochondrial dysfunction in these diseases.

The relationship between hippocampal changes in healthy aging and Alzheimer's disease: a systematic literature review

Introduction

Neurobiological changes in the hippocampus are a common consequence of aging. However, there are differences in the rate of decline and overall volume loss in people with no cognitive impairment compared to those with mild cognitive impairment (MCI) and Alzheimer's disease (AD). This systematic literature review was conducted to determine the relationship between hippocampal atrophy and changes in hippocampal volume in the non-cognitively impaired brain and those with MCI or AD.

Methods

This systematic review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. The PubMed database was searched up to September 15, 2022, for longitudinal magnetic resonance imaging studies reporting hippocampal atrophy or volume change in cognitively normal aging individuals and patients with MCI and/or AD. Study selection was divided into two steps: (1) identification and retrieval of relevant studies; (2) screening the studies by (a) title/abstract and (b) full text. Two teams, each consisting of two independent reviewers, determined whether the publications met the inclusion criteria for the systematic review. An evidence table was populated with data extracted from eligible publications and inclusion in the final systematic review was confirmed.

Results

The systematic search identified 357 publications that were initially screened by title/abstract, of which, 115 publications were retrieved and reviewed by full text for eligibility. Seventeen publications met the eligibility criteria; however, during data extraction, two studies were determined to not meet the inclusion criteria and were excluded. The remaining 15 studies were included in the systematic review. Overall, the results of these studies demonstrated that the hippocampus and hippocampal subfields change over time, with both decreased hippocampal volume and increased rate of hippocampal atrophy observed. Hippocampal changes in AD were observed to be greater than hippocampal changes in MCI, and changes in MCI were observed to be greater than those in normal aging populations.

Conclusion

Published literature suggests that the rate of hippocampal decline and extent of loss is on a continuum that begins in people without cognitive impairment and continues to MCI and AD, and that differences between no cognitive impairment, MCI, and AD are quantitative rather than qualitative.

Eicosanoid signaling in neuroinflammation associated with Alzheimer's disease

Alzheimer's disease (AD) is a prevalent neurodegenerative condition affecting a substantial portion of the global population. It is marked by a complex interplay of factors, including the accumulation of amyloid plaques and tau tangles within the brain, leading to neuroinflammation and neuronal damage. Recent studies have underscored the role of free lipids and their derivatives in the initiation and progression of AD. Eicosanoids, metabolites of polyunsaturated fatty acids like arachidonic acid (AA), emerge as key players in this scenario. Remarkably, eicosanoids can either promote or inhibit the development of AD, and this multifaceted role is determined by how eicosanoid signaling influences the immune responses within the brain. However, the precise molecular mechanisms dictating the dual role of eicosanoids in AD remain elusive. In this comprehensive review, we explore the intricate involvement of eicosanoids in neuronal function and dysfunction. Furthermore, we assess the therapeutic potential of targeting eicosanoid signaling pathways as a viable strategy for mitigating or halting the progression of AD.

Neural ageing and synaptic plasticity: prioritizing brain health in healthy longevity

Ageing is characterized by a gradual decline in the efficiency of physiological functions and increased vulnerability to diseases. Ageing affects the entire body, including physical, mental, and social well-being, but its impact on the brain and cognition can have a particularly significant effect on an individual's overall quality of life. Therefore, enhancing lifespan and physical health in longevity studies will be incomplete if cognitive ageing is over looked. Promoting successful cognitive ageing encompasses the objectives of mitigating cognitive decline, as well as simultaneously enhancing brain function and cognitive reserve. Studies in both humans and animal models indicate that cognitive decline related to normal ageing and age-associated brain disorders are more likely linked to changes in synaptic connections that form the basis of learning and memory. This activity-dependent synaptic plasticity reorganises the structure and function of neurons not only to adapt to new environments, but also to remain robust and stable over time. Therefore, understanding the neural mechanisms that are responsible for age-related cognitive decline becomes increasingly important. In this review, we explore the multifaceted aspects of healthy brain ageing with emphasis on synaptic plasticity, its adaptive mechanisms and the various factors affecting the decline in cognitive functions during ageing. We will also explore the dynamic brain and neuroplasticity, and the role of lifestyle in shaping neuronal plasticity.

Alzheimer's Disease: Combination Therapies and Clinical Trials for Combination Therapy Development

Alzheimer's disease (AD) is a complex multifaceted disease. Recently approved anti-amyloid monoclonal antibodies slow disease progression by approximately 30%, and combination therapy appears necessary to prevent the onset of AD or produce greater slowing of cognitive and functional decline. Combination therapies may address core features, non-specific co-pathology commonly occurring in patients with AD (e.g., inflammation), or non-AD pathologies that may co-occur with AD (e.g., α-synuclein). Combination therapies may be advanced through co-development of more than one new molecular entity or through add-on strategies including an approved agent plus a new molecular entity. Addressing add-on combination therapy is currently urgent since patients on anti-amyloid monoclonal antibodies may be included in clinical trials for experimental agents. Phase 1 information must be generated for each agent in combination drug development. Phase 2 and Phase 3 of add-on therapies may contrast the new molecular entity, the approved agent as standard of care, and the combination. More complex development programs including standard or modified combinatorial designs are required for co-development of two or more new molecular entities. Biomarkers are markedly affected by anti-amyloid monoclonal antibodies, and these effects must be anticipated in add-on trials. Examining target engagement biomarkers and comparing the magnitude and sequence of biomarker changes in those receiving more than one therapy, compared with those on monotherapy, may be informative. Using network-based medicine approaches, computational strategies may identify rational combinations using disease and drug effect network mapping.

Predicting postoperative delirium assessed by the Nursing Screening Delirium Scale in the recovery room for non-cardiac surgeries without craniotomy: A retrospective study using a machine learning approach

Postoperative delirium (POD) contributes to severe outcomes such as death or development of dementia. Thus, it is desirable to identify vulnerable patients in advance during the perioperative phase. Previous studies mainly investigated risk factors for delirium during hospitalization and further used a linear logistic regression (LR) approach with time-invariant data. Studies have not investigated patients' fluctuating conditions to support POD precautions. In this single-center study, we aimed to predict POD in a recovery room setting with a non-linear machine learning (ML) technique using pre-, intra-, and postoperative data. The target variable POD was defined with the Nursing Screening Delirium Scale (Nu-DESC) ≥ 1. Feature selection was conducted based on robust univariate test statistics and L1 regularization. Non-linear multi-layer perceptron (MLP) as well as tree-based models were trained and evaluated-with the receiver operating characteristics curve (AUROC), the area under precision recall curve (AUPRC), and additional metrics-against LR and published models on bootstrapped testing data. The prevalence of POD was 8.2% in a sample of 73,181 surgeries performed between 2017 and 2020. Significant univariate impact factors were the preoperative ASA status (American Society of Anesthesiologists physical status classification system), the intraoperative amount of given remifentanil, and the postoperative Aldrete score. The best model used pre-, intra-, and postoperative data. The non-linear boosted trees model achieved a mean AUROC of 0.854 and a mean AUPRC of 0.418 outperforming linear LR, well as best applied and retrained baseline models. Overall, non-linear machine learning models using data from multiple perioperative time phases were superior to traditional ones in predicting POD in the recovery room. Class imbalance was seen as a main impediment for model application in clinical practice.

Research progress in the mechanism of acupuncture regulating microglia in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease in the central nervous system, characterized by memory and cognitive dysfunction. Acupuncture is an effective means to alleviate the symptoms of AD. Recent studies have shown that microglia play an important role in the occurrence and development of AD. Acupuncture can regulate the activity of microglia, inhibit neuroinflammation, regulate phagocytosis, and clear Aβ Pathological products such as plaque can protect nerve cells and improve cognitive function in AD patients. This article summarizes the relationship between microglia and AD, as well as the research progress in the mechanism of acupuncture regulating microglia in the treatment of AD. The mechanism of acupuncture regulating microglia in the treatment of AD is mainly reviewed from two aspects: inhibiting neuroinflammatory activity and regulating phagocytic function.

Nanoligomers targeting NF-κB and NLRP3 reduce neuroinflammation and improve cognitive function with aging and tauopathy

Neuroinflammation contributes to impaired cognitive function in brain aging and neurodegenerative disorders like Alzheimer's disease, which is characterized by the aggregation of pathological tau. One major driver of both age- and tau-associated neuroinflammation is the NF-κB and NLRP3 signaling axis. However, current treatments targeting NF-κB or NLRP3 may have adverse/systemic effects, and most have not been clinically translatable. In this study, we tested the efficacy of a novel, nucleic acid therapeutic (Nanoligomer) cocktail specifically targeting both NF-κB and NLRP3 in the brain for reducing neuroinflammation and improving cognitive function in old (aged 19 months) wildtype mice, and in rTg4510 tau pathology mice (aged 2 months). We found that 4 weeks of NF-κB/NLRP3-targeting Nanoligomer treatment strongly reduced neuro-inflammatory cytokine profiles in the brain and improved cognitive-behavioral function in both old and rTg4510 mice. These effects of NF-κB/NLRP3-targeting Nanoligomers were also associated with reduced glial cell activation and pathology, favorable changes in transcriptome signatures of glia-associated inflammation (reduced) and neuronal health (increased), and positive systemic effects. Collectively, our results provide a basis for future translational studies targeting both NF-κB and NLRP3 in the brain, perhaps using Nanoligomers, to inhibit neuroinflammation and improve cognitive function with aging and neurodegeneration.

How does the age of control individuals hinder the identification of target genes for Huntington's disease?

Several studies have compared the transcriptome across various brain regions in Huntington's disease (HD) gene-positive and neurologically normal individuals to identify potential differentially expressed genes (DEGs) that could be pharmaceutical or prognostic targets for HD. Despite adhering to technical recommendations for optimal RNA-Seq analysis, none of the genes identified as upregulated in these studies have yet demonstrated success as prognostic or therapeutic targets for HD. Earlier studies included samples from neurologically normal individuals older than the HD gene-positive group. Considering the gradual transcriptional changes induced by aging in the brain, we posited that utilizing samples from older controls could result in the misidentification of DEGs. To validate our hypothesis, we reanalyzed 146 samples from this study, accessible on the SRA database, and employed Propensity Score Matching (PSM) to create a "virtual" control group with a statistically comparable age distribution to the HD gene-positive group. Our study underscores the adverse impact of using neurologically normal individuals over 75 as controls in gene differential expression analysis, resulting in false positives and negatives. We conclusively demonstrate that using such old controls leads to the misidentification of DEGs, detrimentally affecting the discovery of potential pharmaceutical and prognostic markers. This underscores the pivotal role of considering the age of control samples in RNA-Seq analysis and emphasizes its inclusion in evaluating best practices for such investigations. Although our primary focus is HD, our findings suggest that judiciously selecting age-appropriate control samples can significantly improve best practices in differential expression analysis.

Menthol-Modified Quercetin Liposomes with Brain-Targeting Function for the Treatment of Senescent Alzheimer's Disease

Oxidative stress and neuroinflammation in the aging brain are correlated with the development of neurodegenerative diseases, such as Alzheimer's disease (AD). The blood-brain barrier (BBB) poses a significant challenge to the effective delivery of therapeutics for AD. Prior research has demonstrated that menthol (Men) can augment the permeability of the BBB. Consequently, in the current study, we modified Men on the surface of liposomes to construct menthol-modified quercetin liposomes (Men-Qu-Lips), designed to cross the BBB and enhance quercetin (Qu) concentration in the brain for improved therapeutic efficacy. The experimental findings indicate that Men-Qu-Lips exhibited good encapsulation efficiency and stability, successfully crossed the BBB, improved oxidative stress and neuroinflammation in the brains of aged mice, protected neurons, and enhanced their learning and memory abilities.

Nanoligomers targeting NF-κB and NLRP3 reduce neuroinflammation and improve cognitive function with aging and tauopathy

Neuroinflammation contributes to impaired cognitive function in brain aging and neurodegenerative disorders like Alzheimer's disease, which is characterized by the aggregation of pathological tau. One major driver of both age- and tau-associated neuroinflammation is the NF-κB and NLRP3 signaling axis. However, current treatments targeting NF-κB or NLRP3 may have adverse/systemic effects, and most have not been clinically translatable. In this study, we tested the efficacy of a novel, nucleic acid therapeutic (Nanoligomer) cocktail specifically targeting both NF-κB and NLRP3 in the brain for reducing neuroinflammation and improving cognitive function in old (aged 19 months) wildtype mice, and in rTg4510 tau pathology mice (aged 2 months). We found that 4 weeks of NF-κB/NLRP3-targeting Nanoligomer treatment strongly reduced neuro-inflammatory cytokine profiles in the brain and improved cognitive-behavioral function in both old and rTg4510 mice. These effects of NF-κB/NLRP3-targeting Nanoligomers were also associated with reduced glial cell activation and pathology, favorable changes in transcriptome signatures of glia-associated inflammation (reduced) and neuronal health (increased), and positive systemic effects. Collectively, our results provide a basis for future translational studies targeting both NF-κB and NLRP3 in the brain, perhaps using Nanoligomers, to inhibit neuroinflammation and improve cognitive function with aging and neurodegeneration.

Caring for Individuals with Alzheimer's Disease: A Spotlight on Hispanic Caregivers

 A caregiver is a constantly evolving role that an individual most likely undertakes at some point in their lifetime. With discoveries and research in increasing life expectancy, the prevalence of neurological-related diseases, such as Alzheimer's disease (AD) and dementia, is certainly likely to require more caregivers. The demand for AD caregivers is escalating as the prevalence of the disease continues to rise. The projected rise in AD within the Hispanic population in the United States over the next few decades is expected to be the most significant among all ethnic groups. The Hispanic population faces unique dementia risks due to cultural factors like language barriers, lower education, and limited healthcare access. Higher rates of conditions such as diabetes and cardiovascular disease further elevate dementia risk. Family dynamics and caregiving responsibilities also differ, affecting dementia management within Hispanic households. Addressing these distinct challenges requires culturally sensitive approaches to diagnosis, treatment, and support for Hispanic individuals and their family's facing dementia. With AD and other dementia becoming more prevalent, this article will attempt to expand upon the status of caregivers concerning their economic, health, and cultural statuses. We will attempt to focus on the Hispanic caregivers that live in Texas and more specifically, West Texas due to the lack of current literature that applies to this area of Texas. Lastly, we discuss the ramifications of a multitude of factors that affect caregivers in Texas and attempt to provide tools that can be readily available for Hispanics and others alike.

Gut-Brain Axis: Focus on Sex Differences in Neuroinflammation

In recent years, there has been a growing interest in the concept of the "gut-brain axis". In addition to well-studied diseases associated with an imbalance in gut microbiota, such as cancer, chronic inflammation, and cardiovascular diseases, research is now exploring the potential role of gut microbial dysbiosis in the onset and development of brain-related diseases. When the function of the intestinal barrier is altered by dysbiosis, the aberrant immune system response interacts with the nervous system, leading to a state of "neuroinflammation". The gut microbiota-brain axis is mediated by inflammatory and immunological mechanisms, neurotransmitters, and neuroendocrine pathways. This narrative review aims to illustrate the molecular basis of neuroinflammation and elaborate on the concept of the gut-brain axis by virtue of analyzing the various metabolites produced by the gut microbiome and how they might impact the nervous system. Additionally, the current review will highlight how sex influences these molecular mechanisms. In fact, sex hormones impact the brain-gut microbiota axis at different levels, such as the central nervous system, the enteric nervous one, and enteroendocrine cells. A deeper understanding of the gut-brain axis in human health and disease is crucial to guide diagnoses, treatments, and preventive interventions.

Emerging Vistas for the Nutraceutical Withania somnifera in Inflammaging

Inflammaging, a coexistence of inflammation and aging, is a persistent, systemic, low-grade inflammation seen in the geriatric population. Various natural compounds have been greatly explored for their potential role in preventing and treating inflammaging. Withania somnifera has been used for thousands of years in traditional medicine as a nutraceutical for its numerous health benefits including regenerative and adaptogenic effects. Recent preclinical and clinical studies on the role of Withania somnifera and its active compounds in treating aging, inflammation, and oxidative stress have shown promise for its use in healthy aging. We discuss the chemistry of Withania somnifera, the etiology of inflammaging and the protective role(s) of Withania somnifera in inflammaging in key organ systems including brain, lung, kidney, and liver as well as the mechanistic underpinning of these effects. Furthermore, we elucidate the beneficial effects of Withania somnifera in oxidative stress/DNA damage, immunomodulation, COVID-19, and the microbiome. We also delineate a putative protein-protein interaction network of key biomarkers modulated by Withania somnifera in inflammaging. In addition, we review the safety/potential toxicity of Withania somnifera as well as global clinical trials on Withania somnifera. Taken together, this is a synthetic review on the beneficial effects of Withania somnifera in inflammaging and highlights the potential of Withania somnifera in improving the health-related quality of life (HRQoL) in the aging population worldwide.

Folic acid improved memory and learning function in a rat model of neuroinflammation induced by lipopolysaccharide

Folic acid (FA) plays an important role in the maintenance of normal neurological functions such as memory and learning function. Neuroinflammation contributes to the progression of cognitive disorders and Alzheimer's disease. Thus, this study aimed to investigate the effect of FA supplementation on cognitive impairment, oxidative stress, and neuro-inflammation in lipopolysaccharide (LPS)-injured rats. For this purpose, the rats were given FA (5-20 mg/kg/day, oral) for 3 weeks. In the third week, LPS (1 mg/kg/day; intraperitoneal injection) was given before the Morris water maze (MWM) and passive avoidance (PA) tests. Finally, the brains were removed for biochemical assessments. In the MWM test, LPS increased the escape latency and traveled distance to find the platform compared to the control group, whereas all doses of FA decreased them compared to the LPS group. The findings of the probe trial showed that FA increased the traveling time and distance in the target area. LPS impaired the performance of the rats in the PA test. FA increased delay and light time while decreasing the frequency of entry and time in the dark region of PA. LPS increased hippocampal levels of interleukin (IL)-6 and IL-1β. The hippocampal level of malondialdehyde was also increased but thiol content and superoxide dismutase activity were decreased in the LPS group. However, treatment with FA restored the oxidative stress markers along with a reduction in the levels of pro-inflammatory cytokines. In conclusion, FA could ameliorate the memory and learning deficits induced by LPS via normalizing the inflammatory response and oxidative stress markers in the brain.

Emerging antibody-based therapies for Huntington's disease: current status and perspectives for future development

INTRODUCTION

Being an inherited neurodegenerative disease with an identifiable genetic defect, Huntington's disease (HD) is a suitable candidate for early intervention, possibly even in the pre-symptomatic stage. Our recent advances in elucidating the pathogenesis of HD have revealed a series of novel potential therapeutic targets, among which immunotherapies are actively pursued in preclinical experiments.

AREAS COVERED

This review focuses on the potential of antibody-based treatments targeting various epitopes (of mutant huntingtin as well as phosphorylated tau) that are currently evaluated in vitro and in animal experiments. The references used in this review were retrieved from the PubMed database, searching for immunotherapies in HD, and clinical trial registries were reviewed for molecules already evaluated in clinical trials.

EXPERT OPINION

Antibody-based therapies have raised considerable interest in a series of neurodegenerative diseases characterized by deposition of aggregated of aberrantly folded proteins, HD included. Intrabodies and nanobodies can interact with mutant huntingtin inside the nervous cells. However, the conflicting results obtained with some of these intrabodies highlight the need for proper choice of epitopes and for developing animal models more closely mimicking human disease. Approval of these strategies will require a considerable financial and logistic effort on behalf of healthcare systems.

Neuropathological and sociodemographic factors associated with the cortical amyloid load in aging and Alzheimer's disease

Alzheimer's disease (AD) is the leading cause of dementia and is characterized by a progressive decline in cognitive abilities. A pathological hallmark of AD is a region-specific accumulation of the amyloid-beta protein (Aβ). Here, we explored the association between regional Aβ deposition, sociodemographic, and local biochemical factors. We quantified the Aβ burden in postmortem cortical samples from parietal (PCx) and temporal (TCx) regions of 27 cognitively unimpaired (CU) and 15 AD donors, aged 78-100 + years. Histological images of Aβ immunohistochemistry and local concentrations of pathological and inflammatory proteins were obtained at the "Aging, Dementia and TBI Study" open database. We used the area fraction fractionator stereological methodology to quantify the Aβ burden in the gray and white matter within each cortical region. We found higher Aβ burdens in the TCx of AD octogenarians compared to CU ones. We also found higher Aβ loads in the PCx of AD nonagenarians than in AD octogenarians. Moreover, AD women exhibited increased Aβ deposition compared to CU women. Interestingly, we observed a negative correlation between education years and Aβ burden in the white matter of both cortices in CU samples. In AD brains, the Aβ40, Aβ42, and pTau181 isoforms of Aβ and Tau proteins were positively correlated with the Aβ burden. Additionally, in the TCx of AD donors, the proinflammatory cytokine TNFα showed a positive correlation with the Aβ load. These novel findings contribute to understanding the interplay between sociodemographic characteristics, local inflammatory signaling, and the development of AD-related pathology in the cerebral cortex.

The molecular mechanism of aging and the role in neurodegenerative diseases

Aging is a complex and inevitable biological process affected by a combination of external environmental and genetic factors. Humans are currently living longer than ever before, accompanied with aging-related alterations such as diminished autophagy, decreased immunological function, mitochondrial malfunction, stem cell failure, accumulation of somatic and mitochondrial DNA mutations, loss of telomere, and altered nutrient metabolism. Aging leads to a decline in body functions and age-related diseases, for example, Alzheimer's disease, which adversely affects human health and longevity. The quality of life of the elderly is greatly diminished by the increase in their life expectancy rather than healthy life expectancy. With the rise in the age of the global population, aging and related diseases have become the focus of attention worldwide. In this review, we discuss several major mechanisms of aging, including DNA damage and repair, free radical oxidation, telomeres and telomerase, mitochondrial damage, inflammation, and their role in neurodegenerative diseases to provide a reference for the prevention of aging and its related diseases.

Virus-induced brain pathology and the neuroinflammation-inflammation continuum: the neurochemists view

Fascinatingly, an abundance of recent studies has subscribed to the importance of cytotoxic immune mechanisms that appear to increase the risk/trigger for many progressive neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis, and multiple sclerosis. Events associated with the neuroinflammatory cascades, such as ageing, immunologic dysfunction, and eventually disruption of the blood-brain barrier and the "cytokine storm", appear to be orchestrated mainly through the activation of microglial cells and communication with the neurons. The inflammatory processes prompt cellular protein dyshomeostasis. Parkinson's and Alzheimer's disease share a common feature marked by characteristic pathological hallmarks of abnormal neuronal protein accumulation. These Lewy bodies contain misfolded α-synuclein aggregates in PD or in the case of AD, they are Aβ deposits and tau-containing neurofibrillary tangles. Subsequently, these abnormal protein aggregates further elicit neurotoxic processes and events which contribute to the onset of neurodegeneration and to its progression including aggravation of neuroinflammation. However, there is a caveat for exclusively linking neuroinflammation with neurodegeneration, since it's highly unlikely that immune dysregulation is the only factor that contributes to the manifestation of many of these neurodegenerative disorders. It is unquestionably a complex interaction with other factors such as genetics, age, and environment. This endorses the "multiple hit hypothesis". Consequently, if the host has a genetic susceptibility coupled to an age-related weakened immune system, this makes them more susceptible to the virus/bacteria-related infection. This may trigger the onset of chronic cytotoxic neuroinflammatory processes leading to protein dyshomeostasis and accumulation, and finally, these events lead to neuronal destruction. Here, we differentiate "neuroinflammation" and "inflammation" with regard to the involvement of the blood-brain barrier, which seems to be intact in the case of neuroinflammation but defect in the case of inflammation. There is a neuroinflammation-inflammation continuum with regard to virus-induced brain affection. Therefore, we propose a staging of this process, which might be further developed by adding blood- and CSF parameters, their stage-dependent composition and stage-dependent severeness grade. If so, this might be suitable to optimise therapeutic strategies to fight brain neuroinflammation in its beginning and avoid inflammation at all.

Thirty Risk Factors for Alzheimer's Disease Unified by a Common Neuroimmune-Neuroinflammation Mechanism

One of the major obstacles confronting the formulation of a mechanistic understanding for Alzheimer's disease (AD) is its immense complexity-a complexity that traverses the full structural and phenomenological spectrum, including molecular, macromolecular, cellular, neurological and behavioural processes. This complexity is reflected by the equally complex diversity of risk factors associated with AD. However, more than merely mirroring disease complexity, risk factors also provide fundamental insights into the aetiology and pathogenesis of AD as a neurodegenerative disorder since they are central to disease initiation and subsequent propagation. Based on a systematic literature assessment, this review identified 30 risk factors for AD and then extended the analysis to further identify neuroinflammation as a unifying mechanism present in all 30 risk factors. Although other mechanisms (e.g., vasculopathy, proteopathy) were present in multiple risk factors, dysfunction of the neuroimmune-neuroinflammation axis was uniquely central to all 30 identified risk factors. Though the nature of the neuroinflammatory involvement varied, the activation of microglia and the release of pro-inflammatory cytokines were a common pathway shared by all risk factors. This observation provides further evidence for the importance of immunopathic mechanisms in the aetiopathogenesis of AD.

Improvement of Key Molecular Events Linked to Alzheimer's Disease Pathology Using Postbiotics

In the past 50 years, life expectancy has increased by more than 20 years. One consequence of this increase in longevity is the rise of age-related diseases such as dementia. Alzheimer's disease (AD) is the most common form of dementia, accounting for 60-70% of cases. AD pathogenesis is not restricted to the neuronal compartment but includes strong interactions with other brain cells, particularly microglia triggering the release of inflammatory mediators, which contribute to disease progression and severity. There is growing evidence revealing the diverse clinical benefits of postbiotics in many prevalent conditions, including neurodegenerative diseases. Here, we tested the ability of bacterial conditioned media (BCM) derived from selected lactic acid bacteria (LAB) strains to regulate core mechanisms relevant to AD pathophysiology in the microglia cell line BV-2. Levilactobacillus brevis CRL 2013, chosen for its efficient production of the neurotransmitter GABA, and Lactobacillus delbrueckii subsp. lactis CRL 581, known for its anti-inflammatory properties, were selected alongside Enterococcus mundtii CRL 35, a LAB strain that can significantly modulate cytokine production. BCM from all 3 strains displayed antioxidant capabilities, reducing oxidative stress triggered by beta-amyloid oligomers (oAβ1-42). Additionally, BCM effectively mitigated the expression of inflammatory cytokines, namely, TNF-α, IL-1β, and IL-6 triggered by oAβ1-42. Furthermore, our study identified that BCM from CRL 581 inhibit the activity of acetylcholinesterase (AChE), a crucial enzyme in AD progression, in both human erythrocytes and mouse brain tissues. Notably, the inhibitory effect was mediated by low-molecular-weight components of the BCM. L. delbrueckii subsp. lactis CRL 581 emerged as a favorable candidate for production of postbiotics with potential benefits for AD therapy since it demonstrated potent antioxidant activity, reduction of cytokine expression, and partial AChE inhibition. On the other hand, E. mundtii CRL 35 showed that the antioxidant activity failed to inhibit AChE and caused induction of iNOS expression, rendering it unsuitable as a potential therapeutic for AD. This study unveils the potential benefits of LAB-derived postbiotics for the development of new avenues for therapeutic interventions for AD.

COVID-19 and Alzheimer's Disease Share Common Neurological and Ophthalmological Manifestations: A Bidirectional Risk in the Post-Pandemic Future

A growing body of evidence indicates that a neuropathological cross-talk takes place between the coronavirus disease 2019 (COVID-19) -the pandemic severe pneumonia that has had a tremendous impact on the global economy and health since three years after its outbreak in December 2019- and Alzheimer's Disease (AD), the leading cause of dementia among human beings, reaching 139 million by the year 2050. Even though COVID-19 is a primary respiratory disease, its causative agent, the so-called Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), is also endowed with high neuro-invasive potential (Neurocovid). The neurological complications of COVID-19, resulting from the direct viral entry into the Central Nervous System (CNS) and/or indirect systemic inflammation and dysregulated activation of immune response, encompass memory decline and anosmia which are typically associated with AD symptomatology. In addition, patients diagnosed with AD are more vulnerable to SARS-CoV-2 infection and are inclined to more severe clinical outcomes. In the present review, we better elucidate the intimate connection between COVID-19 and AD by summarizing the involved risk factors/targets and the underlying biological mechanisms shared by these two disorders with a particular focus on the Angiotensin-Converting Enzyme 2 (ACE2) receptor, APOlipoprotein E (APOE), aging, neuroinflammation and cellular pathways associated with the Amyloid Precursor Protein (APP)/Amyloid beta (Aβ) and tau neuropathologies. Finally, the involvement of ophthalmological manifestations, including vitreo-retinal abnormalities and visual deficits, in both COVID-19 and AD are also discussed. Understanding the common physiopathological aspects linking COVID-19 and AD will pave the way to novel management and diagnostic/therapeutic approaches to cope with them in the post-pandemic future.

Multifunctional effect of flavonoids from Millettia brandisiana against Alzheimer's disease pathogenesis

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive impairment and neuronal death. Fifteen flavonoids from Millettia brandisiana were evaluated for the multifunctional effect against AD pathogenesis, including butyrylcholine esterase (BuChE) inhibition, anti-amyloid beta (Aβ) aggregation and neuroprotection against hydrogen peroxide (H2O2) toxicity in differentiated human neuroblastoma SH-SY5Y cell. To understand the mechanism and structure-activity relationship, binding interactions between flavonoids and the BuChE and Aβ were investigated in silico. Furthermore, drug-likeness properties and ADMET parameters were evaluated in silico using SwissADME and pKCSM tools. All flavonoids exhibit a good drug-likeness profile. Six flavonoids have potency in BuChE inhibition, and four flavonoids show potency in anti-Aβ aggregation. Flavonoids with the 6″,6″-dimethylchromeno- [2″,3″:7,8]-flavone structure show a favorable multifunctional effect. In silico analysis showed that flavonoids can bind in various positions to the catalytic triad, anionic site, and acyl pocket. In Aβ1-42, potential flavonoids can attach to the central hydrophobic region and the C terminal hydrophobic and interfere with Aβ interchain hydrogen binding. When compared together, it can inhibit multifunctional action with a favorable ADMET parameter and drug-likeness profile. In addition, candidine can prevent neuronal damage in differentiated SH-SY5Y neuroblastoma cells induced by H2O2 in a dose-dependent manner.

Mitochondrial DNA and Inflammation in Alzheimer's Disease

Mitochondrial dysfunction and neuroinflammation are implicated in the pathogenesis of most neurodegenerative diseases, such as Alzheimer's disease (AD). In fact, although a growing number of studies show crosstalk between these two processes, there remain numerous gaps in our knowledge of the mechanisms involved, which requires further clarification. On the one hand, mitochondrial dysfunction may lead to the release of mitochondrial damage-associated molecular patterns (mtDAMPs) which are recognized by microglial immune receptors and contribute to neuroinflammation progression. On the other hand, inflammatory molecules released by glial cells can influence and regulate mitochondrial function. A deeper understanding of these mechanisms may help identify biomarkers and molecular targets useful for the treatment of neurodegenerative diseases. This review of works published in recent years is focused on the description of the mitochondrial contribution to neuroinflammation and neurodegeneration, with particular attention to mitochondrial DNA (mtDNA) and AD.

Mitochondrial dysfunction as a possible trigger of neuroinflammation at post-traumatic stress disorder (PTSD)

Post-traumatic stress disorder (PTSD) is a neuropsychiatric disorder that occurs in approximately 15% of people as a result of some traumatic events. The main symptoms are re-experiencing and avoidance of everything related to this event and hyperarousal. The main component of the pathophysiology of PTSD is an imbalance in the functioning of the hypothalamic-pituitary-adrenal axis (HPA) and development of neuroinflammation. In parallel with this, mitochondrial dysfunction is observed, as in many other diseases. In this review, we focus on the question how mitochondria may be involved in the development of neuroinflammation and its maintaining at PTSD. First, we describe the differences in the operation of the neuro-endocrine system during stress versus PTSD. We then show changes in the activity/expression of mitochondrial proteins in PTSD and how they can affect the levels of hormones involved in PTSD development, as well as how mitochondrial damage/pathogen-associated molecule patterns (DAMPs/PAMPs) trigger development of inflammation. In addition, we examine the possibility of treating PTSD-related inflammation using mitochondria as a target.

Mechanistic Intimate Insights into the Role of Hydrogen Sulfide in Alzheimer's Disease: A Recent Systematic Review

In the rapidly evolving field of Alzheimer's Disease (AD) research, the intricate role of Hydrogen Sulfide (H2S) has garnered critical attention for its diverse involvement in both pathological substrates and prospective therapeutic paradigms. While conventional pathophysiological models of AD have primarily emphasized the significance of amyloid-beta (Aβ) deposition and tau protein hyperphosphorylation, this targeted systematic review meticulously aggregates and rigorously appraises seminal contributions from the past year elucidating the complex mechanisms of H2S in AD pathogenesis. Current scholarly literature accentuates H2S's dual role, delineating its regulatory functions in critical cellular processes-such as neurotransmission, inflammation, and oxidative stress homeostasis-while concurrently highlighting its disruptive impact on quintessential AD biomarkers. Moreover, this review illuminates the nuanced mechanistic intimate interactions of H2S in cerebrovascular and cardiovascular pathology associated with AD, thereby exploring avant-garde therapeutic modalities, including sulfurous mineral water inhalations and mud therapy. By emphasizing the potential for therapeutic modulation of H2S via both donors and inhibitors, this review accentuates the imperative for future research endeavors to deepen our understanding, thereby potentially advancing novel diagnostic and therapeutic strategies in AD.

The Involvement of Neuroinflammation in the Onset and Progression of Parkinson's Disease

Parkinson's disease is a neurodegenerative disease exhibiting the fastest growth in incidence in recent years. As with most neurodegenerative diseases, the pathophysiology is incompletely elucidated, but compelling evidence implicates inflammation, both in the central nervous system and in the periphery, in the initiation and progression of the disease, although it is not yet clear what triggers this inflammatory response and where it begins. Gut dysbiosis seems to be a likely candidate for the initiation of the systemic inflammation. The therapies in current use provide only symptomatic relief, but do not interfere with the disease progression. Nonetheless, animal models have shown promising results with therapies that target various vicious neuroinflammatory cascades. Translating these therapeutic strategies into clinical trials is still in its infancy, and a series of issues, such as the exact timing, identifying biomarkers able to identify Parkinson's disease in early and pre-symptomatic stages, or the proper indications of genetic testing in the population at large, will need to be settled in future guidelines.

κ-Carrageenan Oligosaccharides Protect Nerves by Regulating Microglial Autophagy in Alzheimer's Disease

κ-Carrageenan is a linear sulfated polysaccharide extracted from the cell wall of marine red algae, and its enzymatically digested oligosaccharides (KOS) can inhibit microglial hyperactivation. Alzheimer's disease (AD) is a common chronic neurodegenerative disease, characterized by cognitive and memory impairment accompanied by nerve cell damage. Microglia activation causing enhancement of proinflammatory effects and neurotoxicity is one of the early events in AD disease. In this study, whether KOS have therapeutic or preventive effects in the AD model prepared from APP/PS1 transgenic mice was determined. Learning and memory of AD mice were detected by water maze experiments, and microglial activation-related protein expression and deposition of APP and Aβ1-42 in the brain were examined. The effects of KOS on expressed inflammatory factors and inflammation-related proteins by microglia were tested by cell experiments. Transwell coculture was used to investigate the effect of microglia on neural cell activity after KOS treatment. The results showed that KOS could relieve the clinical symptoms in AD mice, and a decrease in the expression of inflammatory factors and inflammation-related proteins in brain tissue was detected. KOS alleviated nerve cell apoptosis by inhibiting the overactivation of microglia, thus exhibiting neuroprotective effects. Exploring the protective effect of KOS inhibition of microglia inflammation is expected to provide a theoretical basis for KOS as a therapeutic drug for neurodegenerative diseases.

Under the umbrella of depression and Alzheimer's disease physiopathology: Can cannabinoids be a dual-pleiotropic therapy?

Depression and Alzheimer´s disease (AD) are two disorders highly prevalent worldwide. Depression affects more than 300 million people worldwide while AD affects 60-80% of the 55 million cases of dementia. Both diseases are affected by aging with high prevalence in elderly and share not only the main brain affected areas but also several physiopathological mechanisms. Depression disease is already ascribed as a risk factor to the development of AD. Despite the wide diversity of pharmacological treatments currently available in clinical practice for depression management, they remain associated to a slow recovery process and to treatment-resistant depression. On the other hand, AD treatment is essentially based in symptomatology relieve. Thus, the need for new multi-target treatments arises. Herein, we discuss the current state-of-art regarding the contribution of the endocannabinoid system (ECS) in synaptic transmission processes, synapses plasticity and neurogenesis and consequently the use of exogenous cannabinoids in the treatment of depression and on delaying the progression of AD. Besides the well-known imbalance of neurotransmitter levels, including serotonin, noradrenaline, dopamine and glutamate, recent scientific evidence highlights aberrant spine density, neuroinflammation, dysregulation of neurotrophic factor levels and formation of amyloid beta (Aβ) peptides, as the main physiopathological mechanisms compromised in depression and AD. The contribution of the ECS in these mechanisms is herein specified as well as the pleiotropic effects of phytocannabinoids. At the end, it became evident that Cannabinol, Cannabidiol, Cannabigerol, Cannabidivarin and Cannabichromene may act in novel therapeutic targets, presenting high potential in the pharmacotherapy of both diseases.

From the Bush to the Brain: Preclinical Stages of Ethnobotanical Anti-Inflammatory and Neuroprotective Drug Discovery-An Australian Example

The Australian rainforest is a rich source of medicinal plants that have evolved in the face of dramatic environmental challenges over a million years due to its prolonged geographical isolation from other continents. The rainforest consists of an inherent richness of plant secondary metabolites that are the most intense in the rainforest. The search for more potent and more bioavailable compounds from other plant sources is ongoing, and our short review will outline the pathways from the discovery of bioactive plants to the structural identification of active compounds, testing for potency, and then neuroprotection in a triculture system, and finally, the validation in an appropriate neuro-inflammatory mouse model, using some examples from our current research. We will focus on neuroinflammation as a potential treatment target for neurodegenerative diseases including multiple sclerosis (MS), Parkinson's (PD), and Alzheimer's disease (AD) for these plant-derived, anti-inflammatory molecules and highlight cytokine suppressive anti-inflammatory drugs (CSAIDs) as a better alternative to conventional nonsteroidal anti-inflammatory drugs (NSAIDs) to treat neuroinflammatory disorders.

Alzheimer's Disease Treatment: The Search for a Breakthrough

As the search for modalities to cure Alzheimer's disease (AD) has made slow progress, research has now turned to innovative pathways involving neural and peripheral inflammation and neuro-regeneration. Widely used AD treatments provide only symptomatic relief without changing the disease course. The recently FDA-approved anti-amyloid drugs, aducanumab and lecanemab, have demonstrated unclear real-world efficacy with a substantial side effect profile. Interest is growing in targeting the early stages of AD before irreversible pathologic changes so that cognitive function and neuronal viability can be preserved. Neuroinflammation is a fundamental feature of AD that involves complex relationships among cerebral immune cells and pro-inflammatory cytokines, which could be altered pharmacologically by AD therapy. Here, we provide an overview of the manipulations attempted in pre-clinical experiments. These include inhibition of microglial receptors, attenuation of inflammation and enhancement of toxin-clearing autophagy. In addition, modulation of the microbiome-brain-gut axis, dietary changes, and increased mental and physical exercise are under evaluation as ways to optimize brain health. As the scientific and medical communities work together, new solutions may be on the horizon to slow or halt AD progression.

Anti-Alzheimers molecular mechanism of icariin: insights from gut microbiota, metabolomics, and network pharmacology

BACKGROUND

Icariin (ICA), an active ingredient extracted from Epimedium species, has shown promising results in the treatment of Alzheimer's disease (AD), although its potential therapeutic mechanism remains largely unknown. This study aimed to investigate the therapeutic effects and the underlying mechanisms of ICA on AD by an integrated analysis of gut microbiota, metabolomics, and network pharmacology (NP).

METHODS

The cognitive impairment of mice was measured using the Morris Water Maze test and the pathological changes were assessed using hematoxylin and eosin staining. 16S rRNA sequencing and multi-metabolomics were performed to analyze the alterations in the gut microbiota and fecal/serum metabolism. Meanwhile, NP was used to determine the putative molecular regulation mechanism of ICA in AD treatment.

RESULTS

Our results revealed that ICA intervention significantly improved cognitive dysfunction in APP/PS1 mice and typical AD pathologies in the hippocampus of the APP/PS1 mice. Moreover, the gut microbiota analysis showed that ICA administration reversed AD-induced gut microbiota dysbiosis in APP/PS1 mice by elevating the abundance of Akkermansia and reducing the abundance of Alistipe. Furthermore, the metabolomic analysis revealed that ICA reversed the AD-induced metabolic disorder via regulating the glycerophospholipid and sphingolipid metabolism, and correlation analysis revealed that glycerophospholipid and sphingolipid were closely related to Alistipe and Akkermansia. Moreover, NP indicated that ICA might regulate the sphingolipid signaling pathway via the PRKCA/TNF/TP53/AKT1/RELA/NFKB1 axis for the treatment of AD.

CONCLUSION

These findings indicated that ICA may serve as a promising therapeutic approach for AD and that the ICA-mediated protective effects were associated with the amelioration of microbiota disturbance and metabolic disorder.

Nature's Toolbox Against Tau Aggregation: An Updated Review of Current Research

Tau aggregation is a hallmark of several neurodegenerative disorders, such as Alzheimer's disease (AD), frontotemporal dementia, and progressive supranuclear palsy. Hyperphosphorylated tau is believed to contribute to the degeneration of neurons and the development of these complex diseases. Therefore, one potential treatment for these illnesses is to prevent or counteract tau aggregation. In recent years, interest has been increasing in developing nature-derived tau aggregation inhibitors as a potential treatment for neurodegenerative disorders. Researchers have become increasingly interested in natural compounds with multifunctional features, such as flavonoids, alkaloids, resveratrol, and curcumin, since these molecules can interact simultaneously with the various targets of AD. Recent studies have demonstrated that several natural compounds can inhibit tau aggregation and promote the disassembly of pre-formed tau aggregates. Nature-derived tau aggregation inhibitors hold promise as a potential treatment for neurodegenerative disorders. However, it is important to note that more research is needed to fully understand the mechanisms by which these compounds exert their effects and their safety and efficacy in preclinical and clinical studies. Nature-derived inhibitors of tau aggregation are a promising new direction in the research of neurodegenerative complexities. This review focuses on the natural products that have proven to be a rich supply for inhibitors in tau aggregation and their uses in neurodegenerative complexities, including AD.