A review: inflammatory process in Alzheimer's disease, role of cytokines

Elevated protease-activated receptor 4 (PAR4) gene expression in Alzheimer's disease predicts cognitive decline

Platelet activation of protease-activated receptor 4 (PAR4) and thrombin are at the top of a chain of events leading to fibrin deposition, microinfarcts, blood-brain barrier disruption, and inflammation. We evaluated mRNA expression of the PAR4 gene F2RL3 in human brain and global cognitive performance in participants with and without cognitive impairment or dementia. Data were acquired from the Religious Orders Study (ROS) and the Rush Memory and Aging Project (MAP). F2RL3 mRNA was elevated in AD cases and was associated with worse retrospective longitudinal cognitive performance. Moreover, F2RL3 expression interacted with clinical AD diagnosis on longitudinal cognition whereas this relationship was attenuated in individuals without cognitive impairment. Additionally, when adjusting for the effects of AD neuropathology, F2RL3 expression remained a significant predictor of cognitive decline. F2RL3 expression correlated positively with transcript levels of proinflammatory markers including TNFα, IL-1β, NFκB, and fibrinogen α/β/γ. Together, these results reveal that F2RL3 mRNA expression is associated with multiple AD-relevant outcomes and its encoded product, PAR4, may play a role in disease pathogenesis.

Differential responses of primary neuron-secreted MCP-1 and IL-9 to type 2 diabetes and Alzheimer's disease-associated metabolites

Type 2 diabetes (T2D) is implicated as a risk factor for Alzheimer's disease (AD), the most common form of dementia. In this work, we investigated neuroinflammatory responses of primary neurons to potentially circulating, blood-brain barrier (BBB) permeable metabolites associated with AD, T2D, or both. We identified nine metabolites associated with protective or detrimental properties of AD and T2D in literature (lauric acid, asparagine, fructose, arachidonic acid, aminoadipic acid, sorbitol, retinol, tryptophan, niacinamide) and stimulated primary mouse neuron cultures with each metabolite before quantifying cytokine secretion via Luminex. We employed unsupervised clustering, inferential statistics, and partial least squares discriminant analysis to identify relationships between cytokine concentration and disease-associations of metabolites. We identified MCP-1, a cytokine associated with monocyte recruitment, as differentially abundant between neurons stimulated by metabolites associated with protective and detrimental properties of AD and T2D. We also identified IL-9, a cytokine that promotes mast cell growth, to be differentially associated with T2D. Indeed, cytokines, such as MCP-1 and IL-9, released from neurons in response to BBB-permeable metabolites associated with T2D may contribute to AD development by downstream effects of neuroinflammation.

Therapeutic effects of tetrandrine in inflammatory diseases: a comprehensive review

Inflammation can be triggered by any factor. The primary pathological manifestations can be summarized as the deterioration, exudation, and proliferation of local tissues, which can cause systemic damage in severe cases. Inflammatory lesions are primarily localized but may interact with body systems to cause provocative storms, parenchymal organ lesions, vascular and central nervous system necrosis, and other pathologic responses. Tetrandrine (TET) is a bisbenzylquinoline alkaloid extracted from the traditional Chinese herbal medicine Stephania tetrandra, which has been shown to have significant efficacy in inflammatory conditions such as rheumatoid arthritis, hepatitis, nephritis, etc., through NF-κB, MAPK, ERK, and STAT3 signaling pathways. TET can regulate the body's imbalanced metabolic pathways, reverse the inflammatory process, reduce other pathological damage caused by inflammation, and prevent the vicious cycle. More importantly, TET does not disrupt body's normal immune function while clearing the body's inflammatory state. Therefore, it is necessary to pay attention to its dosage and duration during treatment to avoid unexpected side effects caused by a long half-life. In summary, TET has a promising future in treating inflammatory diseases. The author reviews current therapeutic studies of TET in inflammatory conditions to provide some ideas for subsequent anti-inflammatory studies of TET.

Galectin-9 and Tim-3 are upregulated in response to microglial activation induced by the peptide Amyloid-β (25-35)

Galectins are a group of β-galactoside-binding lectins associated with regulating immunological response. In the brains of AD patients and 5xFAD (familial AD) mice, galectin-3 (Gal-3) was highly upregulated and found to be expressed in microglia associated with Aβ plaques. However, the participation of other galectins, specifically galectin-9 (Gal-9) and T-cell immunoglobulin and mucin domain 3 (Tim-3) receptors, are unknown in the inflammatory response. The experimental model of the Aβ25-35 peptide will allow us to study the mechanisms of neuroinflammation and describe the changes in the expression of the Gal-9 and Tim-3 receptor. This study aimed to evaluate whether Aβ25-35 peptide administration into the lateral ventricles of rats upregulated Gal-9 and Tim-3 implicated in the modulation of neuroinflammation. The vehicle or Aβ25-35 peptide (1 μg/μL) was bilaterally administered into the lateral ventricles of the rat, and control group. After the administration of the Aβ25-35 peptide, animals were tested for learning (day 29) and spatial memory (day 30) in the novel object recognition test (NOR). On day 31, hippocampus was examined for morphological changes by Nilss stain, biochemical changes by NO2 and MDA, immunohistochemical analysis by astrocytes (GFAP), microglia (Iba1), Gal-9 and Tim-3, and western blot. Our results show the administration of the Aβ25-35 peptide into the lateral ventricles of rats induce memory impairment in the NOR by increases the oxidative stress and inflammatory response. This result is associated with an upregulation of Gal-9 and Tim-3 predominantly detected in the microglia cells of Aβ25-35-treated rats with respect to the control group. Gal-9 and Tim-3 are upregulated in activated microglia that could modulate the inflammatory response and damage in neurodegenerative processes induced by the Aβ25-35 peptide. Therefore, we suggest that Gal-9 and Tim-3 participate in the inflammatory process induced by the administration of the Aβ25-35 peptide.

Association of multiple metabolic and cardiovascular markers with the risk of cognitive decline and mortality in adults with Alzheimer's disease and AD-related dementia or cognitive decline: a prospective cohort study

Background and objectives

There is a scarcity of data stemming from large-scale epidemiological longitudinal studies focusing on potentially preventable and controllable risk factors for Alzheimer's disease (AD) and AD-related dementia (ADRD). This study aimed to examine the effect of multiple metabolic factors and cardiovascular disorders on the risk of cognitive decline and AD/ADRD.

Methods

We analyzed a cohort of 6,440 participants aged 45-84 years at baseline. Multiple metabolic and cardiovascular disorder factors included the five components of the metabolic syndrome [waist circumference, high blood pressure (HBP), elevated glucose and triglyceride (TG) concentrations, and reduced high-density lipoprotein cholesterol (HDL-C) concentrations], C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), factor VIII, D-dimer, and homocysteine concentrations, carotid intimal-medial thickness (CIMT), and urine albumin-to-creatinine ratio (ACR). Cognitive decline was defined using the Cognitive Abilities Screening Instrument (CASI) score, and AD/ADRD cases were classified using clinical diagnoses.

Results

Over an average follow-up period of 13 years, HBP and elevated glucose, CRP, homocysteine, IL-6, and ACR concentrations were significantly associated with the risk of mortality in the individuals with incident AD/ADRD or cognitive decline. Elevated D-dimer and homocysteine concentrations, as well as elevated ACR were significantly associated with incident AD/ADRD. Elevated homocysteine and ACR were significantly associated with cognitive decline. A dose-response association was observed, indicating that an increased number of exposures to multiple risk factors corresponded to a higher risk of mortality in individuals with cognitive decline or with AD/ADRD.

Conclusion

Findings from our study reaffirm the significance of preventable and controllable factors, including HBP, hyperglycemia, elevated CRP, D-dimer, and homocysteine concentrations, as well as, ACR, as potential risk factors for cognitive decline and AD/ADRD.

Sociodemographic patterns in biomarkers of aging in the Add Health cohort

Biomarkers in population health research serve as indicators of incremental physiological deterioration and contribute to our understanding of mechanisms through which social disparities in health unfold over time. Yet, few population-based studies incorporate biomarkers of aging in early midlife, when disease risks may emerge and progress across the life course. We describe the distributions of several biomarkers of inflammation and neurodegeneration and their variation by sociodemographic characteristics using blood samples collected during Wave V of the National Longitudinal Study of Adolescent to Adult Health (ages 33-44 years). Higher mean levels of inflammatory and neurodegenerative biomarkers were associated with greater socioeconomic disadvantage. For example, the neurodegenerative markers, Neurofilament Light Chain and total Tau proteins were higher among lower income groups, though the relationship was not statistically significant. Similarly, proinflammatory marker Tumor Necrosis Factor-α (TNF-α) levels were higher among those with lower education. Significant differences in the mean levels of other proinflammatory markers were observed by race/ethnicity, sex, census region, BMI, and smoking status. These descriptive findings indicate that disparities in biomarkers associated with aging are already evident among young adults in their 30s and attention should focus on age-related disease risk earlier in the life course.

Comparison between dynamic versus static models and real-time monitoring of neuronal dysfunction in an amyloid-β induced neuronal toxic model on a chip platform

Microfluidics-based organs-on-a-chip offer a promising method for dynamic and 3-dimensional (3D) cell culture to evaluate the cell behaviors within the biomimetic environment. The purpose of this study was to establish neural network connections in a 3D neural stem cell (NSC)-based system with an interstitial level of flow for simulating the brain microenvironment toward a dynamic amyloid-β (Aβ) induced neuronal toxic model on a chip and to compare the biological effects and neurite dysfunction between static and dynamic systems. The brain-on-a-chip system consisted of an impedance analyzing layer, a structured well with a connected channel, and an interface coating with polypeptide films fabricated with modification based on our previous study. The cytotoxicity and percentage of neuron/astrocyte differentiation were all compared in both static and dynamic brain-on-a-chip systems. Reactive oxygen species production, neuron marker expression and neurotransmitter-acetylcholine release were all compared to evaluate functional neurite losses in both static and dynamic systems with/without Aβ addition. Moreover, real-time impedance recording was used to consecutively monitor the neurite connection/disconnection in both static and dynamic brain-on-a-chip systems. The NSC-based dynamic brain-on-a-chip may enable the application of different neurodegenerative disease in vitro models for pathogenesis studies, drug discovery and novel therapeutic method development.

Rat primary cortical cell tri-culture to study effects of amyloid-beta on microglia function

Introduction

The etiology and progression of sporadic Alzheimer's Disease (AD) have been studied for decades. One proposed mechanism is that amyloid-beta (Aβ) proteins induce neuroinflammation, synapse loss, and neuronal cell death. Microglia play an especially important role in Aβ clearance, and alterations in microglial function due to aging or disease may result in Aβ accumulation and deleterious effects on neuronal function. However, studying these complex factors in vivo , where numerous confounding processes exist, is challenging, and until recently, in vitro models have not allowed sustained culture of microglia, astrocytes and neurons in the same culture. Here, we employ a tri-culture model of rat primary neurons, astrocytes, and microglia and compare it to co-culture (neurons and astrocytes) and mono-culture enriched for microglia to study microglial function (i.e., motility and Aβ clearance) and proteomic response to exogenous Aβ.

Methods

We established cortical co-culture (neurons and astrocytes), tri-culture (neurons, astrocytes, and microglia), and mono-culture (microglia) from perinatal rat pups. On days in vitro (DIV) 7 - 14, the cultures were exposed to fluorescently-labeled Aβ (FITC-Aβ) particles for varying durations. Images were analyzed to determine the number of FITC-Aβ particles after specific lengths of exposure. A group of cells were stained for βIII-tubulin, GFAP, and Iba1 for morphological analysis via quantitative fluorescence microscopy. Cytokine profiles from conditioned media were obtained. Live-cell imaging with images acquired every 5 minutes for 4 hours was employed to extract microglia motility parameters (e.g., Euclidean distance, migration speed, directionality ratio).

Results and discussion

FITC-Aβ particles were more effectively cleared in the tri-culture compared to the co-culture. This was attributed to microglia engulfing FITC-Aβ particles, as confirmed via epifluorescence and confocal microscopy. Adding FITC-Aβ significantly increased the size of microglia, but had no significant effect on neuronal surface coverage or astrocyte size. Analysis of the cytokine profile upon FITC-Aβ addition revealed a significant increase in proinflammatory cytokines (TNF-α, IL-1α, IL-1β, IL-6) in tri-culture, but not co-culture. In addition, Aβ addition altered microglia motility marked by swarming-like motion with decreased Euclidean distance yet unaltered speed. These results highlight the importance of cell-cell communication in microglia function (e.g., motility and Aβ clearance) and the utility of the tri-culture model to further investigate microglia dysfunction in AD.

Association of dietary live microbe intake with various cognitive domains in US adults aged 60 years or older

The purpose of this study was to explore whether dietary live microbe intake is associated with various cognitive domains using data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014. And the specific relationship between low, medium and high dietary live microbe intake groups and cognitive ability of the elderly. Dietary live microbe intake was calculated from 24-h diet recall interviews. Cognitive function was assessed using the number symbol substitution test (DSST, which measures processing speed), the animal fluency test (AFT, which measures executive function), the Alzheimer's Registry sub-test (CERAD, which measures memory), and the Composite Z-score, which adds the Z-values of individual tests. Multiple linear regression models and restricted cubic bar graphs were used to investigate the relationship between live microbe intake and cognitive performance. A total of 2,450 participants aged 60 or older were included. Live microbe intake was positively correlated with cognitive ability on the whole. Specifically, when the intake of low, medium and high live microbe was > 2640 g, > 39 g and > 0 g respectively, the CERAD, DSST, AFT and compositive-Z score of the subjects increased with the increase of microbial intake (P < 0.05). In American adults age 60 or older, higher intakes of live microbes were associated with better cognitive performance, especially after a certain amount was reached.

Viral Infections, Are They a Trigger and Risk Factor of Alzheimer's Disease?

Alzheimer's Disease (AD), a progressive and debilitating condition, is reported to be the most common type of dementia, with at least 55 million people believed to be currently affected. Many causation hypotheses of AD exist, yet the intriguing link between viral infection and its possible contribution to the known etiology of AD has become an attractive focal point of research for the field and a challenging study task. In this review, we will explore the historical perspective and milestones that led the field to investigate the viral connection to AD. Specifically, several viruses such as Herpes Simplex Virus 1 (HSV-1), Zika virus (ZIKV), and severe cute respiratory syndrome coronavirus 2 (SARS-CoV-2), along with several others mentioned, include the various viruses presently considered within the field. We delve into the strong evidence implicating these viruses in the development of AD such as the lytic replication and axonal transport of HSV-1, the various mechanisms of ZIKV neurotropism through the human protein Musashi-1 (MSI1), and the spread of SARS-CoV-2 through the transfer of the virus through the BBB endothelial cells to glial cells and then to neurons via transsynaptic transfer. We will also explore beyond these mere associations by carefully analyzing the potential mechanisms by which these viruses may contribute to AD pathology. This includes but is not limited to direct neuronal infections, the dysregulation of immune responses, and the impact on protein processing (Aβ42 and hyperphosphorylated tau). Controversies and challenges of the virus-AD relationship emerge as we tease out these potential mechanisms. Looking forward, we emphasize future directions, such as distinct questions and proposed experimentations to explore, that the field should take to tackle the remaining unanswered questions and the glaring research gaps that persist. Overall, this review aims to provide a comprehensive survey of the past, present, and future of the potential link between viral infections and their association with AD development while encouraging further discussion.

Mechanistic insights into the role of amyloid-β in innate immunity

Colocalization of microbial pathogens and the β-amyloid peptide (Aβ) in the brain of Alzheimer's disease (AD) patients suggests that microbial infection may play a role in sporadic AD. Aβ exhibits antimicrobial activity against numerous pathogens, supporting a potential role for Aβ in the innate immune response. While mammalian amyloid is associated with disease, many bacteria form amyloid fibrils to fortify the biofilm that protects the cells from the surrounding environment. In the microbial AD hypothesis, Aβ aggregates in response to infection to combat the pathogen. We hypothesize that this occurs through toxic Aβ oligomers that contain α-sheet structure and form prior to fibrillization. De novo designed α-sheet peptides specifically bind to the α-sheet structure present in the oligomers of both bacterial and mammalian amyloidogenic proteins to neutralize toxicity and inhibit aggregation. Here, we measure the effect of E. coli on Aβ, including upregulation, aggregation, and toxicity. Additionally, we determined the effect of Aβ structure on E. coli amyloid fibrils, or curli comprised of the CsgA protein, and biofilm formation. We found that curli formation by E. coli increased Aβ oligomer production, and Aβ oligomers inhibited curli biogenesis and reduced biofilm cell density. Further, curli and biofilm inhibition by Aβ oligomers increased E. coli susceptibility to gentamicin. Toxic oligomers of Aβ and CsgA interact via α-sheet interactions, neutralizing their toxicity. These results suggest that exposure to toxic oligomers formed by microbial pathogens triggers Aβ oligomer upregulation and aggregation to combat infection via selective interactions between α-sheet oligomers to neutralize toxicity of both species with subsequent inhibition of fibrillization.

E-Cigarette Exposure Alters Neuroinflammation Gene and Protein Expression in a Murine Model: Insights from Perinatally Exposed Offspring and Post-Birth Mothers

The use of E-cigarettes, often considered a safer alternative to traditional smoking, has been associated with high rates of cellular toxicity, genetic alterations, and inflammation. Neuroinflammatory impacts of cigarette smoking during pregnancy have been associated with increased risks of adverse childhood health outcomes; however, it is still relatively unknown if the same propensity is conferred on offspring by maternal vaping during gestation. Results from our previous mouse inhalation studies suggest such a connection. In this earlier study, pregnant C57BL/6 mice were exposed daily to inhaled E-cig aerosols (i.e., propylene glycol and vegetable glycerin, [PG/VG]), with or without nicotine (16 mg/mL) by whole-body inhalation throughout gestation (3 h/d; 5 d/week; total ~3-week) and continuing postnatally from post-natal day (PND) 4-21. As neuroinflammation is involved in the dysregulation of glucose homeostasis and weight gain, this study aimed to explore genes associated with these pathways in 1-mo.-old offspring (equivalent in humans to 12-18 years of age). Results in the offspring demonstrated a significant increase in glucose metabolism protein levels in both treatment groups compared to filtered air controls. Gene expression analysis in the hypothalamus of 1 mo. old offspring exposed perinatally to E-cig aerosols, with and without nicotine, revealed significantly increased gene expression changes in multiple genes associated with neuroinflammation. In a second proof-of-principal parallel study employing the same experimental design, we shifted our focus to the hippocampus of the postpartum mothers. We targeted the mRNA levels of several neurotrophic factors (NTFs) indicative of neuroinflammation. While there were suggestive changes in mRNA expression in this study, levels failed to reach statistical significance. These studies highlight the need for ongoing research on E-cig-induced alterations in neuroinflammatory pathways.

Therapeutic potential of natural products in inflammation: underlying molecular mechanisms, clinical outcomes, technological advances, and future perspectives

Chronic inflammation is a common underlying factor in many major diseases, including heart disease, diabetes, cancer, and autoimmune disorders, and is responsible for up to 60% of all deaths worldwide. Metformin, statins, and corticosteroids, and NSAIDs (non-steroidal anti-inflammatory drugs) are often given as anti-inflammatory pharmaceuticals, however, often have even more debilitating side effects than the illness itself. The natural product-based therapy of inflammation-related diseases has no adverse effects and good beneficial results compared to substitute conventional anti-inflammatory medications. In this review article, we provide a concise overview of present pharmacological treatments, the pathophysiology of inflammation, and the signaling pathways that underlie it. In addition, we focus on the most promising natural products identified as potential anti-inflammatory therapeutic agents. Moreover, preclinical studies and clinical trials evaluating the efficacy of natural products as anti-inflammatory therapeutic agents and their pragmatic applications with promising outcomes are reviewed. In addition, the safety, side effects and technical barriers of natural products are discussed. Furthermore, we also summarized the latest technological advances in the discovery and scientific development of natural products-based medicine.

Cerebrovascular disease drives Alzheimer plasma biomarker concentrations in adults with Down syndrome

Importance

By age 40 years over 90% of adults with Down syndrome (DS) have Alzheimer's disease (AD) pathology and most progress to dementia. Despite having few systemic vascular risk factors, individuals with DS have elevated cerebrovascular disease (CVD) markers that track with the clinical progression of AD, suggesting a role for CVD that is hypothesized to be mediated by inflammatory factors.

Objective

To examine the pathways through which small vessel CVD contributes to AD-related pathophysiology and neurodegeneration in adults with DS.

Design

Cross sectional analysis of neuroimaging, plasma, and clinical data.

Setting

Participants were enrolled in Alzheimer's Biomarker Consortium - Down Syndrome (ABC-DS), a multisite study of AD in adults with DS.

Participants

One hundred eighty-five participants (mean [SD] age=45.2 [9.3] years) with available MRI and plasma biomarker data were included. White matter hyperintensity (WMH) volumes were derived from T2-weighted FLAIR MRI scans and plasma biomarker concentrations of amyloid beta (Aβ42/Aβ40), phosphorylated tau (p-tau217), astrocytosis (glial fibrillary acidic protein, GFAP), and neurodegeneration (neurofilament light chain, NfL) were measured with ultrasensitive immunoassays.

Main Outcomes and Measures

We examined the bivariate relationships of WMH, Aβ42/Aβ40, p-tau217, and GFAP with age-residualized NfL across AD diagnostic groups. A series of mediation and path analyses examined causal pathways linking WMH and AD pathophysiology to promote neurodegeneration in the total sample and groups stratified by clinical diagnosis.

Results

There was a direct and indirect bidirectional effect through GFAP of WMH on p-tau217 concentration, which was associated with NfL concentration in the entire sample. Among cognitively stable participants, WMH was directly and indirectly, through GFAP, associated with p-tau217 concentration, and in those with MCI, there was a direct effect of WMH on p-tau217 and NfL concentrations. There were no associations of WMH with biomarker concentrations among those diagnosed with dementia.

Conclusions and Relevance

The findings suggest that among individuals with DS, CVD promotes neurodegeneration by increasing astrocytosis and tau pathophysiology in the presymptomatic phases of AD. This work joins an emerging literature that implicates CVD and its interface with neuroinflammation as a core pathological feature of AD in adults with DS.

Oligodendrocyte progenitor cells in Alzheimer's disease: from physiology to pathology

Oligodendrocyte progenitor cells (OPCs) play pivotal roles in myelin formation and phagocytosis, communicating with neighboring cells and contributing to the integrity of the blood-brain barrier (BBB). However, under the pathological circumstances of Alzheimer's disease (AD), the brain's microenvironment undergoes detrimental changes that significantly impact OPCs and their functions. Starting with OPC functions, we delve into the transformation of OPCs to myelin-producing oligodendrocytes, the intricate signaling interactions with other cells in the central nervous system (CNS), and the fascinating process of phagocytosis, which influences the function of OPCs and affects CNS homeostasis. Moreover, we discuss the essential role of OPCs in BBB formation and highlight the critical contribution of OPCs in forming CNS-protective barriers. In the context of AD, the deterioration of the local microenvironment in the brain is discussed, mainly focusing on neuroinflammation, oxidative stress, and the accumulation of toxic proteins. The detrimental changes disturb the delicate balance in the brain, impacting the regenerative capacity of OPCs and compromising myelin integrity. Under pathological conditions, OPCs experience significant alterations in migration and proliferation, leading to impaired differentiation and a reduced ability to produce mature oligodendrocytes. Moreover, myelin degeneration and formation become increasingly active in AD, contributing to progressive neurodegeneration. Finally, we summarize the current therapeutic approaches targeting OPCs in AD. Strategies to revitalize OPC senescence, modulate signaling pathways to enhance OPC differentiation, and explore other potential therapeutic avenues are promising in alleviating the impact of AD on OPCs and CNS function. In conclusion, this review highlights the indispensable role of OPCs in CNS function and their involvement in the pathogenesis of AD. The intricate interplay between OPCs and the AD brain microenvironment underscores the complexity of neurodegenerative diseases. Insights from studying OPCs under pathological conditions provide a foundation for innovative therapeutic strategies targeting OPCs and fostering neurodegeneration. Future research will advance our understanding and management of neurodegenerative diseases, ultimately offering hope for effective treatments and improved quality of life for those affected by AD and related disorders.

Mesenchymal stem cell-derived rapid drug screening system for Alzheimer's disease for the identification of novel drugs

A reliable and efficient in vitro model is needed to screen drugs for Alzheimer's disease (AD), as many drugs are currently in the developmental stage. To address this, we developed an in vitro model using amniotic membrane-derived mesenchymal stem cells (AM-MSCs) to screen novel drugs for AD. We differentiated AM-MSCs into neurons and degenerated them using beta amyloid1-42 (Aß). We then tested AD drugs, which are commercially available such as donepezil, rivastigmine, memantine, citicoline, and two novel drugs, that is, probucol, an anti-hyperlipidaemic drug, and NMJ-2, a cinnamic acid analogue for their potential to protect the cells against neurodegeneration. We used gene expression and immunofluorescence staining to assess the neuroprotective ability of these drugs. We also measured the ability of these drugs to reduce lactate dehydrogenase, reactive oxygen species, and nitric oxide levels, as well as their ability to stabilize the mitochondrial membrane potential and increase acetylcholine (ACh) levels. The AD drugs and novel drugs reduced cytotoxicity and oxidative stress, stabilized mitochondrial membrane potential, and restored ACh levels. Furthermore, they reduced BACE1 expression, with a concomitant increase in the expression of cholinergic markers. This AM-MSCs-based AD-like model has immense potential to be an accurate human model and an alternative to animal models for testing a large number of lead compounds in a short time. Our results also suggest that the novel drugs probucol and NMJ-2 may protect against Aß-induced neurodegeneration.

Ferroptosis, Pyroptosis, and Cuproptosis in Alzheimer's Disease

Alzheimer's disease (AD), the most common type of dementia, is a neurodegenerative disorder characterized by progressive cognitive dysfunction. Epidemiological investigation has demonstrated that, after cardiovascular and cerebrovascular diseases, tumors, and other causes, AD has become a major health issue affecting elderly individuals, with its mortality rate acutely increasing each year. Regulatory cell death is the active and orderly death of genetically determined cells, which is ubiquitous in the development of living organisms and is crucial to the regulation of life homeostasis. With extensive research on regulatory cell death in AD, increasing evidence has revealed that ferroptosis, pyroptosis, and cuproptosis are closely related to the occurrence, development, and prognosis of AD. This paper will review the molecular mechanisms of ferroptosis, pyroptosis, and cuproptosis and their regulatory roles in AD to explore potential therapeutic targets for the treatment of AD.

Cognitive enhancing effects of pazopanib in D‑galactose/ovariectomized Alzheimer's rat model: insights into the role of RIPK1/RIPK3/MLKL necroptosis signaling pathway

Necroptosis, a programmed form of necrotic cell death carried out by receptor-interacting serine/threonine protein kinase 1 (RIPK1) and RIPK3, has been found to be implicated in the pathogenesis of Alzheimer's disease (AD). An FDA-approved anti-cancer drug, pazopanib, is reported to possess potent inhibitory effect against necroptosis via interfering with RIPK1. So far, there are no existing data on the influence of pazopanib on necroptotic pathway in AD. Thus, this study was designed to explore the impact of pazopanib on cognitive impairment provoked by ovariectomy (OVX) together with D-galactose (D-Gal) administration in rats and to scrutinize the putative signaling pathways underlying pazopanib-induced effects. Animals were allocated into four groups; the first and second groups were exposed to sham operation and administered normal saline and pazopanib (5 mg/kg/day, i.p.), respectively, for 6 weeks, while the third and fourth groups underwent OVX then were injected with D-Gal (150 mg/kg/day, i.p.); concomitantly with pazopanib in the fourth group for 6 weeks. Pazopanib ameliorated cognitive deficits as manifested by improved performance in the Morris water maze besides reversing the histological abnormalities. Pazopanib produced a significant decline in p-Tau and amyloid beta (Aβ) plaques. The neuroprotective effect of pazopanib was revealed by hampering neuroinflammation, mitigating neuronal death and suppressing RIPK1/RIPK3/MLKL necroptosis signaling pathway. Accordingly, hindering neuroinflammation and the necroptotic RIPK1/RIPK3/MLKL pathway could contribute to the neuroprotective effect of pazopanib in D-Gal/OVX rat model. Therefore, this study reveals pazopanib as a valuable therapeutic agent in AD that warrants future inspection to provide further data regarding its neuroprotective effect.

Simvastatin improves learning and memory impairment via gut-brain axis regulation in an ovariectomized/D-galactose Alzheimer's rat model

AIM

Alzheimer's disease (AD) is the most prevalent form of dementia with multiple etiology and no effective remedy. Statins are a group of medicines that are basically used to lower cholesterol. However, several studies have recently done to assess the potential relationship between statins use and dementia but presented controversial results.

METHODS

In this study, using ovariectomy and D-galactose injection, a model of AD was induced in female rats, and then the protective effects of oral administration of simvastatin were investigated. shuttle box and Y-maze tests were done to assess the animals' learning and memory performance. Using GC-MC, ELISA, Immunohistochemistry and tissue staining techniques, changes in the amount of short-chain fatty acids (SCFAs), plasma and hippocampus neuroinflammatory markers and histological changes in the intestine and hippocampus were assessed in sham, disease and treatment groups.

KEY FINDINGS

Oral administration of simvastatin improved the gut microbiome activity (increased the amount of SCFAs in fecal samples) and strengthened the tight junctions of intestinal cells. Moreover, simvastatin reduced the amount of TNF-α and IL-1β in plasma and hippocampus. Also, cell death and Amyloid plaques notably decreased in the simvastatin-treated hippocampal tissue. All these physiological changes led to better performance in behavioral tasks in the treatment group in comparison to the disease group.

SIGNIFICANCE

These findings provide evidence that simvastatin may improve gut-brain axis followed by improvement in learning and memory via an anti-inflammatory effect.

Exploring the role of COX-2 in Alzheimer's disease: Potential therapeutic implications of COX-2 inhibitors

This review highlights the potential role of cyclooxygenase-2 enzyme (COX-2) in the pathogenesis of Alzheimer's disease (AD) and the potential therapeutic use of non-steroidal anti-inflammatory drugs (NSAIDs) in the management of AD. In addition to COX-2 enzymes role in inflammation, the formation of amyloid plaques and neurofibrillary tangles in the brain, the review emphasizes that COXs-2 have a crucial role in normal synaptic activity and plasticity, and have a relationship with acetylcholine, tau protein, and beta-amyloid (Aβ) which are the main causes of Alzheimer's disease. Furthermore, the review points out that COX-2 enzymes have a relationship with kinase enzymes, including Cyclin Dependent Kinase 5 (CDK5) and Glycogen Synthase Kinase 3β (GSK3β), which are known to play a role in tau phosphorylation and are strongly associated with Alzheimer's disease. Therefore, the use of drugs like NSAIDs may be a hopeful approach for managing AD. However, results from studies examining the effectiveness of NSAIDs in treating AD have been mixed and further research is needed to fully understand the mechanisms by which COX-2 and NSAIDs may be involved in the development and progression of AD and to identify new therapeutic strategies.

1,25-Dihydroxy Vitamin D3 Facilitates the M2 Polarization and β-Amyloid Uptake by Human Microglia in a TREM2-Dependent Manner

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by dementia as the primary clinical symptom. The production and accumulation of aggregated β-amyloid (Aβ) in patient brain tissues is one of the hallmarks of AD pathogenesis. Microglia, brain-resident macrophages, produce inflammatory cytokines in response to Aβ oligomers or fibrils exacerbating Aβ pathology in AD. HMO6 cells were treated with Aβ42 in the presence or absence of 1,25-dihydroxy vitamin D₃ (1,25(OH)₂D₃) to determine its potential immunomodulatory effects, and the expression of pro-/anti-inflammatory cytokines, M1/M2-associated markers, Toll-like receptors (TLRs), and triggering receptor expressed on myeloid cells 2 (TREM2) was examined. 1,25(OH)₂D₃ was found to suppress Aβ-induced expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), M1 markers (CD86 and iNOS), and TLR2/4, whilst increasing the expression of anti-inflammatory cytokines (IL-4, IL-10, and CCL17) and M2 markers (CD206 and Arg-1). Furthermore, 1,25(OH)₂D₃ promoted TREM2 expression and Aβ uptake by HMO6 cells, and the enhancement of Aβ uptake and M2 polarization was revealed to be TREM2-dependent. The findings of this study suggest that 1,25(OH)₂D₃ facilitates M2 polarization and Aβ uptake in a TREM2-dependent manner.

JNK3 Overexpression in the Entorhinal Cortex Impacts on the Hippocampus and Induces Cognitive Deficiencies and Tau Misfolding

c-Jun N-terminal kinases (JNKs) are a family of protein kinases activated by a myriad of stimuli consequently modulating a vast range of biological processes. In human postmortem brain samples affected with Alzheimer's disease (AD), JNK overactivation has been described; however, its role in AD onset and progression is still under debate. One of the earliest affected areas in the pathology is the entorhinal cortex (EC). Noteworthy, the deterioration of the projection from EC to hippocampus (Hp) point toward the idea that the connection between EC and Hp is lost in AD. Thus, the main objective of the present work is to address if JNK3 overexpression in the EC could impact on the hippocampus, inducing cognitive deficits. Data obtained in the present work suggest that JNK3 overexpression in the EC influences the Hp leading to cognitive impairment. Moreover, proinflammatory cytokine expression and Tau immunoreactivity were increased both in the EC and in the Hp. Therefore, activation of inflammatory signaling and induction of Tau aberrant misfolding caused by JNK3 could be responsible for the observed cognitive impairment. Altogether, JNK3 overexpression in the EC may impact on the Hp inducing cognitive dysfunction and underlie the alterations observed in AD.

A systematic review of exercise modalities that reduce pro-inflammatory cytokines in humans and animals' models with mild cognitive impairment or dementia

PURPOSE

To investigate which type, frequency, duration, intensity, and volume of chronic exercise might more strongly reduce pro-inflammatory cytokines and enhance anti-inflammatory cytokines in human and animal models with Mild Cognitive Impairment (MCI) or dementia.

DESIGN

A systematic review.

DATA SOURCE

English-language search of 13 electronic databases: Web of Science, PubMed/Medline, Sport Discus, Scopus, Cochrane, Psych Net, Springer, ScienceDirect, Pascal & Francis, Sage journals, Pedro, Google Scholar, and Sage.

INCLUSION CRITERIA

(i) human and animal studies that included exercise, physical activity, or fitness training as an experimental intervention, (ii) studies that addressed MCI, dementia, or AD, (iii) studies that focused on measuring cytokines and/or other inflammatory and/or neuroinflammatory immune markers, (iii) studies that examined inflammatory indicators in blood, CSF (Cerebrospinal Fluid), and brain tissue.

RESULTS

Of the 1290 human and animal studies found, 38 were included for qualitative analysis, 11 human articles, 27 animal articles, and two articles addressing both human and animal protocols. In the animal model, physical exercise decreased pro-inflammatory markers in 70.8 % of the articles and anti-inflammatory cytokines: IL -4, IL -10, IL-4β, IL -10β, and TGF-β in 26 % of articles. Treadmill running, resistance exercise, and swimming exercise reduce pro-inflammatory cytokines and increase anti-inflammatory cytokines. In the human model, 53.9 % of items reduced pro-inflammatory proteins and 23 % increased anti-inflammatory proteins. Cycling exercise, multimodal, and resistance training effectively decreased pro-inflammatory cytokines.

CONCLUSION

In rodent animal models with AD phenotype, treadmill, swimming, and resistance training remain good interventions that can delay various mechanisms of dementia progression. In the human model, aerobic, multimodal, and resistance training are beneficial in both MCI and AD. Multimodal training of moderate to high intensity multimodal exercise is effective for MCI. Voluntary cycling training, moderate- or high-intensity aerobic exercise is effective in mild AD patients.

The pathomimetic oAβ25–35 model of Alzheimer's disease: Potential for screening of new therapeutic agents

Alzheimer's disease (AD) is the most common form of dementia in the elderly, currently affecting more than 40 million people worldwide. The two main histopathological hallmarks of AD were identified in the 1980s: senile plaques (composed of aggregated amyloid-β (Aβ) peptides) and neurofibrillary tangles (composed of hyperphosphorylated tau protein). In the human brain, both Aβ and tau show aggregation into soluble and insoluble oligomers. Soluble oligomers of Aβ include their most predominant forms - Aβ_1-40 and Aβ_1-42 - as well as shorter peptides such as Aβ_25-35 or Aβ_25-35/40. Most animal models of AD have been developed using transgenesis, based on identified human mutations. However, these familial forms of AD represent less than 1% of AD cases. In this context, the idea emerged in the 1990s to directly inject the Aβ_25-35 fragment into the rodent brain to develop an acute model of AD that could mimic the disease's sporadic forms (99% of all cases). This review aims to: (1) summarize the biological activity of Aβ_25-35, focusing on its impact on the main structural and functional alterations observed in AD (cognitive deficits, APP misprocessing, tau system dysfunction, neuroinflammation, oxidative stress, cholinergic and glutamatergic alterations, HPA axis dysregulation, synaptic deficits and cell death); and (2) confirm the interest of this pathomimetic model in AD research, as it has helped identify and characterize many molecules (marketed, in clinical development, and in preclinical testing), and to the development of alternative approaches for AD prevention and therapy. Today, the Aβ_25-35 model appears as a first-intent choice model to rapidly screen the symptomatic or neuroprotective potencies of new compounds, chemical series, or innovative therapeutic strategies.

Neuroprotective Effect of Methanolic Ajwa Seed Extract on Lipopolysaccharide-Induced Memory Dysfunction and Neuroinflammation: In Vivo, Molecular Docking and Dynamics Studies

Islamic literature has indicated that daily consumption of Ajwa dates heals a variety of chronic diseases and disorders. The current research investigates the neuroprotective effect of methanolic Ajwa seed extract (MASE) on lipopolysaccharide (LPS)-induced cognitive deficits using multiple approaches. For animal studies, MASE (200 and 400 mg/kg, p.o.) was administrated for thirty consecutive days, and four doses of LPS (250 µg/kg, i.p.) were injected to induce neurotoxicity. Memory functions were evaluated using elevated plus-maze and novel object recognition tests. Acetylcholine (ACh) and neuroinflammatory markers (cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and transforming growth factor (TGF)-β1) were estimated in brain tissues. Studies of molecular docking and dynamics were conducted to provide insight into the molecular-level mechanisms. MASE administration resulted in a significant reversal of LPS-induced memory impairment in both maze models. Both doses of MASE elevated the ACh levels in an LPS-treated rat brain. In addition, the extract lowered COX-2 and proinflammatory cytokines (TNF-α and IL-6) while increasing anti-inflammatory cytokines (IL-10 and TGF-β1) in LPS-treated brain tissues. Molecular modeling results revealed that the compound's ellagic acid, epicatechin, catechin, kaempferol, quercetin, and apigenin have the potential to act as a dual inhibitor of acetylcholinesterase (AChE) and COX-2 and can be responsible for the improvement of both cholinergic and inflammatory conditions, while the cinnamic acid, hesperidin, hesperetin, narengin, and rutin compounds are responsible only for the improvement of cholinergic transmission. The above compounds acted by interacting with the key residues Trp84, Asp72, Gly118, Ser200, Tyr334, and His440, which are responsible for the hydrolysis of ACh in AChE, while the COX-2 is inhibited by interacting with the residues (Val349, Leu352, Tyr355, Tyr385, Ala527, Ser530, and Leu531) of the hydrophobic channel. By promoting cholinergic activity and protecting neuroinflammation in the rat brain, MASE provides neuroprotection against LPS-induced cognitive deficits. Our preliminary findings will help with further drug discovery processes related to neuroinflammation-related neurodegeneration.

Neuroinflammation in Alzheimer's Disease: Current Progress in Molecular Signaling and Therapeutics

Alzheimer's disease, a neurodegenerative disease with amyloid beta accumulation as a major hallmark, has become a dire global health concern as there is a lack of clear understanding of the causative agent. It is a major cause of dementia which is increasing exponentially with age. Alzheimer's disease is marked by tau hyperphosphorylation and amyloid beta accumulation that robs people of their memories. Amyloid beta deposition initiated a spectrum of microglia-activated neuroinflammation, and microglia and astrocyte activation elicited expressions of various inflammatory and anti-inflammatory cytokines. Neuroinflammation is one of the cardinal features of Alzheimer's disease. Pro-inflammatory cytokine signaling plays multifarious roles in neurodegeneration and neuroprotection. Induction of proinflammatory signaling leads to discharge of immune mediators which affect functions of neurons and cause cell death. Sluggish anti-inflammatory system also contributes to neuroinflammation. Numerous pathways like NFκB, p38 MAPK, Akt/mTOR, caspase, nitric oxide, and COX are involved in triggering brain immune cells like astrocytes and microglia to secrete inflammatory cytokines such as tumor necrosis factor, interleukins, and chemokines and participate in Alzheimer's disease pathology. PPAR-γ agonists tend to boost the phagocytosis of amyloid beta and decrease the inflammatory cytokine IL-1β. Recent findings suggest the cross-link between gut microbiota and neuroinflammation contributing in AD which has been explained in this study. The role of cellular, molecular pathways and involvement of inflammatory mediators in neuroinflammation has also been described; targeting them could be a potential therapeutic strategy for treatment of AD.

Links between COVID-19 and Alzheimer's Disease-What Do We Already Know?

Alzheimer's disease (AD) is a life-changing condition whose etiology is explained by several hypotheses. Recently, a new virus contributed to the evidence of viral involvement in AD: the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the COVID-19 coronavirus disease. AD was found to be one of the most common COVID-19 comorbidities, and it was found to increase mortality from this disease as well. Moreover, AD patients were observed to present with the distinct clinical features of COVID-19, with delirium being prevalent in this group. The SARS-CoV-2 virus enters host cells through the angiotensin-converting enzyme 2 (ACE2) receptor. ACE2 is overexpressed in brains with AD, which thus increases the viral invasion. Furthermore, the inhibition of the ACE2 receptor by the SARS-CoV-2 virus may also decrease the brain-derived neurotrophic factor (BDNF), contributing to neurodegeneration. The ApoE ε4 allele, which increases the risk of AD, was found to facilitate the SARS-CoV-2 entry into cells. Furthermore, the neuroinflammation and oxidative stress existing in AD patients enhance the inflammatory response associated with COVID-19. Moreover, pandemic and associated social distancing measures negatively affected the mental health, cognitive function, and neuro-psychiatric symptoms of AD patients. This review comprehensively covers the links between COVID-19 and Alzheimer's disease, including clinical presentation, molecular mechanisms, and the effects of social distancing.

Inhibition of Pro-Inflammatory Microglia with Minocycline Improves Cognitive and Sleep-Wake Dysfunction Under Respiratory Stress in a Sporadic Model for Alzheimer's Disease

BACKGROUND

Neuroinflammation in Alzheimer's disease (AD) can occur due to excessive activation of microglia in response to the accumulation of amyloid-β peptide (Aβ). Previously, we demonstrated an increased expression of this peptide in the locus coeruleus (LC) in a sporadic model for AD (streptozotocin, STZ; 2 mg/kg, ICV). We hypothesized that the STZ-AD model exhibits neuroinflammation, and treatment with an inhibitor of microglia (minocycline) can reverse the cognitive, respiratory, sleep, and molecular disorders of this model.

OBJECTIVE

To evaluate the effect of minocycline treatment in STZ model disorders.

METHODS

We treated control and STZ-treated rats for five days with minocycline (30 mg/kg, IP) and evaluated cognitive performance, chemoreflex response to hypercapnia and hypoxia, and total sleep time. Additionally, quantification of Aβ, microglia analyses, and relative expression of cytokines in the LC were performed.

RESULTS

Minocycline treatment improved learning and memory, which was concomitant with a decrease in microglial cell density and re-establishment of morphological changes induced by STZ in the LC region. Minocycline did not reverse the STZ-induced increase in CO2 sensitivity during wakefulness. However, it restored the daytime sleep-wake cycle in STZ-treated animals to the same levels as those observed in control animals. In the LC, levels of A and expression of Il10, Il1b, and Mcp1 mRNA remained unaffected by minocycline, but we found a strong trend of minocycline effect on Tnf- α.

CONCLUSION

Our findings suggest that minocycline effectively reduces microglial recruitment and the inflammatory morphological profile in the LC, while it recovers cognitive performance and restores the sleep-wake pattern impaired by STZ.

Interleukin-17 (IL-17) triggers systemic inflammation, peripheral vascular dysfunction, and related prothrombotic state in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent forms of neurodegenerative disorders. Previously, we have shown that in vivo administration of an IL-17 neutralizing antibody (IL-17Ab) rescues amyloid-β-induced neuro-inflammation and memory impairment, demonstrating the pivotal role of IL-17 in AD-derived cognitive deficit. Recently, AD has been recognized as a more intriguing pathology affecting vascular networks and platelet function. However, not much is known about peripheral vascular inflammation and how pro-inflammatory circulating cells/mediators could affect peripheral vessels' function. This study aimed to evaluate whether IL-17Ab treatment could also impact peripheral AD features, such as systemic inflammation, peripheral vascular dysfunction, and related pro-thrombotic state in a non-genetic mouse model of AD. Mice were injected intracerebroventricularly with Aβ_1-42 peptide (3 μg/3 μl). To evaluate the systemic/peripheral protective profile of IL-17Ab, we used an intranasal administration of IL-17Ab (1 μg/10 μl) at 5, 12, and 19 days after Aβ_1-42 injection. Circulating Th17/Treg cells and related cyto-chemokines, haematological parameters, vascular/endothelial reactivity, platelets and coagulation function in mice were evaluated. IL-17Ab treatment ameliorates the systemic/peripheral inflammation, immunological perturbance, vascular/endothelial impairment and pro-thrombotic state, suggesting a key role for this cytokine in fostering inflammatory processes that characterize the multifaced aspects of AD.

Ageing, Metabolic Dysfunction, and the Therapeutic Role of Antioxidants

The gradual ageing of the world population has been accompanied by a dramatic increase in the prevalence of obesity and metabolic diseases, especially type 2 diabetes. The adipose tissue dysfunction associated with ageing and obesity shares many common physiological features, including increased oxidative stress and inflammation. Understanding the mechanisms responsible for adipose tissue dysfunction in obesity may help elucidate the processes that contribute to the metabolic disturbances that occur with ageing. This, in turn, may help identify therapeutic targets for the treatment of obesity and age-related metabolic disorders. Because oxidative stress plays a critical role in these pathological processes, antioxidant dietary interventions could be of therapeutic value for the prevention and/or treatment of age-related diseases and obesity and their complications. In this chapter, we review the molecular and cellular mechanisms by which obesity predisposes individuals to accelerated ageing. Additionally, we critically review the potential of antioxidant dietary interventions to counteract obesity and ageing.

Transplanting Microglia for Treating CNS Injuries and Neurological Diseases and Disorders, and Prospects for Generating Exogenic Microglia

Microglia are associated with a wide range of both neuroprotective and neuroinflammatory functions in the central nervous system (CNS) during development and throughout lifespan. Chronically activated and dysfunctional microglia are found in many diseases and disorders, such as Alzheimer's disease, Parkinson's disease, and CNS-related injuries, and can accelerate or worsen the condition. Transplantation studies designed to replace and supplement dysfunctional microglia with healthy microglia offer a promising strategy for addressing microglia-mediated neuroinflammation and pathologies. This review will cover microglial involvement in neurological diseases and disorders and CNS-related injuries, current microglial transplantation strategies, and different approaches and considerations for generating exogenic microglia.

A Systematic Review of Dietary Supplements in Alzheimer's Disease

Alzheimer's is the most common neurodegenerative disease among the aging population, which has been a major global challenge. The pathogenesis of the disease is still undetermined but postulated to be involved in various mechanisms including oxidative stress, excitotoxicity, inflammation, cell death, genetic factors, protein accumulation, and degradation. There are few Food and Drug Administration (FDA)-approved drugs available for the treatment of Alzheimer's disease (AD) that have limited benefits along with associated adverse effects. A retrospective review of randomized double-blind controlled trials of various supplements used in AD patients was performed on a PubMed search from January 1983 to March 2022. We found 10 articles that have shown positive outcomes in various cognitive domains. We conclude that there should be a global standard to endorse the quality and safety of these supplements.

Anti-Inflammatory Effect of Traditional Chinese Medicine on the Concept of Mind-Body Interface

In this chapter, we conducted a systemic literature review for the anti-inflammatory effects of Traditional Chinese Medicine (TCM) applying molecular mechanisms focusing on the neuroinflammation and gut-brain axis in three neuropsychiatric disorders: major depressive disorder, Alzheimer's disease, and Parkinson's disease. We demonstrated the anti-inflammation or immunomodulation effects of TCM, including acupuncture, from basic and clinical research, including cellular and molecular approaches. In conclusion, inflammation plays a critical role in the neuropsychopathological process. At the same time, anti-inflammation seems to be the common biological pathway for the effects of TCM and acupuncture in depression, Alzheimer's disease, and Parkinson's disease.

Immunomodulation in age-related disorders and nanotechnology interventions

Recently, the aging population has increased exponentially around the globe bringing more challenges to improve quality of life in those populations while reducing the economic burden on healthcare systems. Aging is associated with changes in the immune system culminating in detrimental effects such as immune dysfunction, immunosenescence, and chronic inflammation. Age-related decline of immune functions is associated with various pathologies including cardiovascular, autoimmune, neurodegenerative, and infectious diseases to name a few. Conventional treatment addresses the onset of age-related diseases by early detection of risk factors, administration of vaccines as preventive care, immunomodulatory treatment, and other dietary supplements. However, these approaches often come with systemic side-effects, low bioavailability of therapeutic agents, and poor outcomes seen in the elderly. Recent innovations in nanotechnology have led to the development of novel biomaterials/nanomaterials, which explore targeted drug delivery and immunomodulatory interactions in vivo. Current nanotechnology-based immunomodulatory approaches that have the potential to be used as therapeutic interventions for some prominent age-related diseases are discussed here. Finally, we explore challenges and future aspects of nanotechnology in the treatments of age-related disorders to improve quality of life in the elderly. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Role of pro-inflammatory cytokines in Alzheimer's disease and neuroprotective effects of pegylated self-assembled nanoscaffolds

Neurodegeneration and synaptic loss in Alzheimer's disease (AD) lead to impairment in memory functions. Neuroinflammation causes activation of microglia and astrocytes cells that locally and systemically produces inflammatory cytokines which can serve as early diagnostic markers or therapeutic targets in AD. Pro-inflammatory cytokines (Interleukins (IL-1β, IL-6 and IL-10) and tumor necrosis factor (TNF α)) levels were estimated in serum, cerebral tissue, hepatic tissue, and renal tissue in treatment groups of scopolamine-induced amnesia mice model using ELISA protocol. The results showed that cerebral tissue of AD mice exhibited elevated levels of IL1β, IL6, IL10 and TNFα which indicate contribution of pro-inflammatory cytokines in the progression of AD. A significant reduction in the concentration of IL1β, IL-10 and TNF-α were noticed in serum, cerebral tissue and hepatic tissue of animal group treated with marketed memantine tablet (Admenta), pure memantine drug (MEMp), memantine-poly (lactic-co-glycolic acid) self-assembled nanoscaffolds (MEM-PLGA) SANs, Polyethylene Glycol coated memantine-poly (lactic-co-glycolic acid) self-assembled nanoscaffolds [(PEG-MEM-PLGA) SANs] and Polyethylene Glycol coated memantine-poly [(lactic-co-glycolic acid)] self-assembled nanoscaffolds grafted with Bone Marrow Derived Stem Cell ((PEG-MEM-PLGA) SANs-BMSc), whereas a high level of IL-6 was observed in hepatic tissue, cerebral tissue and renal tissues of normal and AD induced mice which showed the emerging potential of IL-6 cytokines that can trigger either neurons survival after injury or causing neurodegeneration and cell apoptosis. The Neuroregenerative potential of stem cells helps in the proliferation of neuronal cell and thus improves cognition in AD animal model.

Analysis of shared underlying mechanism in neurodegenerative disease

In this review, the relationship between bioenergetics, mitochondrial dysfunction, and inflammation will be and how they contribute to neurodegeneration, specifically in Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS) will be reviewed. Long-term changes in mitochondrial function, autophagy dysfunction, and immune activation are commonalities shared across these age-related disorders. Genetic risk factors for these diseases support an autophagy-immune connection in the underlying pathophysiology. Critical areas of deeper evaluation in these bioenergetic processes may lead to potential therapeutics with efficacy across multiple neurodegenerative diseases.

Females exhibit higher GluA2 levels and outperform males in active place avoidance despite increased amyloid plaques in TgF344-Alzheimer's rats

Alzheimer's disease (AD) is a progressive neurodegenerative disease that is most prevalent in females. While estrogen provides neuroprotection in females, sex mediated differences in the development of AD pathology are not fully elucidated. Therefore, comparing events between sexes in early-stage AD pathology may reveal more effective therapeutic targets of intervention. To address sex differences, we analyzed early-stage 9-month male and female TgF344-AD (Tg-AD) rats, an AD model carrying the APPswe and Presenilin 1 (PS1ΔE9) mutations that develops progressive age-dependent AD pathology similar to humans. Tg-AD females significantly outperformed Tg-AD males in the active place avoidance (aPAT) test that assesses hippocampal-dependent spatial learning and memory. However, comparisons between Tg-AD male or female rats and their WT counterparts showed significant deficits for female but not male rats. Nevertheless, Tg-AD females experienced significantly less hippocampal neuronal loss with higher GluA2 subunit levels than Tg-AD males. Unexpectedly, Tg-AD females displayed higher levels of hippocampal amyloid plaques than Tg-AD males. Thus, we propose that GluA2 may provide a neuroprotective function for Tg-AD females in our rat model by mitigating cognitive impairment independently of amyloid plaques. Elucidating this protective mechanism in AD could lead to new targets for early intervention.

Mast Cell Cytokines in Acute and Chronic Gingival Tissue Inflammation: Role of IL-33 and IL-37

Much evidence suggests autoimmunity in the etiopathogenesis of periodontal disease. In fact, in periodontitis, there is antibody production against collagen, DNA, and IgG, as well as increased IgA expression, T cell dysfunction, high expression of class II MHC molecules on the surface of gingival epithelial cells in inflamed tissues, activation of NK cells, and the generation of antibodies against the azurophil granules of polymorphonuclear leukocytes. In general, direct activation of autoreactive immune cells and production of TNF can activate neutrophils to release pro-inflammatory enzymes with tissue damage in the gingiva. Gingival inflammation and, in the most serious cases, periodontitis, are mainly due to the dysbiosis of the commensal oral microbiota that triggers the immune system. This inflammatory pathological state can affect the periodontal ligament, bone, and the entire gingival tissue. Oral tolerance can be abrogated by some cytokines produced by epithelial cells and activated immune cells, including mast cells (MCs). Periodontal cells and inflammatory-immune cells, including mast cells (MCs), produce cytokines and chemokines, mediating local inflammation of the gingival, along with destruction of the periodontal ligament and alveolar bone. Immune-cell activation and recruitment can be induced by inflammatory cytokines, such as IL-1, TNF, IL-33, and bacterial products, including lipopolysaccharide (LPS). IL-1 and IL-33 are pleiotropic cytokines from members of the IL-1 family, which mediate inflammation of MCs and contribute to many key features of periodontitis and other inflammatory disorders. IL-33 activates several immune cells, including lymphocytes, Th2 cells, and MCs in both innate and acquired immunological diseases. The classic therapies for periodontitis include non-surgical periodontal treatment, surgery, antibiotics, anti-inflammatory drugs, and surgery, which have been only partially effective. Recently, a natural cytokine, IL-37, a member of the IL-1 family and a suppressor of IL-1b, has received considerable attention for the treatment of inflammatory diseases. In this article, we report that IL-37 may be an important and effective therapeutic cytokine that may inhibit periodontal inflammation. The purpose of this paper is to study the relationship between MCs, IL-1, IL-33, and IL-37 inhibition in acute and chronic inflamed gingival tissue.

Synergistic influence of cytokine gene polymorphisms over the risk of dementia: A multifactor dimensionality reduction analysis

OBJECTIVE

Evidence supports the important role of neuroinflammation in some types of dementia. This study aimed to evaluate the effect of epistasis of gene cytokines such as interleukin (IL)-α, IL-6, tumor necrosis factor (TNFα), and interferon-gamma (IFN-γ) on the susceptibility to the development of dementia.

MATERIALS AND METHODS

In the study, 221 patients diagnosed with dementia and 710 controls were included. The multifactor-dimensionality reduction (MDR) analysis was performed to identify the epistasis between SNP located in genes of IL-α (rs1800587), IL-6 (rs1800796), TNFα (rs361525 and rs1800629), and IFNγ (rs2069705). The best risk prediction model was identified based on precision and cross-validation consistency.

RESULTS

Multifactor-dimensionality reduction analysis detected a significant model with the genes TNFα, IFNγ, IL1α, and IL6 (prediction success: 72%, p < 0.0001). When risk factors were analyzed with these polymorphisms, the model achieved a similar prediction for dementia as the genes-only model.

CONCLUSION

These data indicate that gene-gene interactions form significant models to identify populations susceptible to dementia.

Neuromodulation Applied to Diseases: The Case of HRV Biofeedback

The vagus or “wandering” nerve is the main branch of the parasympathetic nervous system (PNS), innervating most internal organs crucial for health. Activity of the vagus nerve can be non-invasively indexed by heart-rate variability parameters (HRV). Specific HRV parameters predict less all-cause mortality, lower risk of and better prognosis after myocardial infarctions, and better survival in cancer. A non-invasive manner for self-activating the vagus is achieved by performing a slow-paced breathing technique while receiving visual feedback of one’s HRV, called HRV-biofeedback (HRV-B). This article narratively reviews the biological mechanisms underlying the role of vagal activity and vagally mediated HRV in hypertension, diabetes, coronary heart disease (CHD), cancer, pain, and dementia. After searching the literature for HRV-B intervention studies in each condition, we report the effects of HRV-B on clinical outcomes in these health conditions, while evaluating the methodological quality of these studies. Generally, the levels of evidence for the benefits of HRV-B is high in CHD, pain, and hypertension, moderate in cancer, and poor in diabetes and dementia. Limitations and future research directions are discussed.

Recent Treatment Strategies in Alzheimer's Disease and Chronic Traumatic Encephalopathy

Neurotrauma has been well linked to the progression of neurodegenerative disease. Much work has been done characterizing chronic traumatic encephalopathy, but less has been done regarding the contribution to Alzheimer's Disease. This review focuses on AD and its association with neurotrauma. Emerging clinical trials are discussed as well as novel mechanisms. We then address how some of these mechanisms are shared with CTE and emerging pre-clinical studies. This paper is a user-friendly resource that summarizes the emerging findings and proposes further investigation into key areas of interest. It is intended to serve as a catalyst for both research teams and clinicians in the quest to improve effective treatment and diagnostic options.

DNA methylation changes and inflammaging in aging-associated diseases

Aging as an inevitable phenomenon is associated with pervasive changes in physiological functions. There is a relationship between aging and the increase of several chronic diseases. Most age-related disorders are accompanied by an underlying chronic inflammatory state, as demonstrated by local infiltration of inflammatory cells and greater levels of proinflammatory cytokines in the bloodstream. Within inflammaging, many epigenetic events, especially DNA methylation, change. During the aging process, due to aberrations of DNA methylation, biological processes are disrupted, leading to the emergence or progression of a variety of human diseases, including cancer, neurodegenerative disorders, cardiovascular disease and diabetes. The focus of this review is on DNA methylation, which is involved in inflammaging-related activities, and how its dysregulation leads to human disorders.

Pathophysiology of Depression: Stingless Bee Honey Promising as an Antidepressant

Depression is a debilitating psychiatric disorder impacting an individual’s quality of life. It is the most prevalent mental illness across all age categories, incurring huge socio-economic impacts. Most depression treatments currently focus on the elevation of neurotransmitters according to the monoamine hypothesis. Conventional treatments include tricyclic antidepressants (TCAs), norepinephrine–dopamine reuptake inhibitors (NDRIs), monoamine oxidase inhibitors (MAOIs), and serotonin reuptake inhibitors (SSRIs). Despite numerous pharmacological strategies utilising conventional drugs, the discovery of alternative medicines from natural products is a must for safer and beneficial brain supplement. About 30% of patients have been reported to show resistance to drug treatments coupled with functional impairment, poor quality of life, and suicidal ideation with a high relapse rate. Hence, there is an urgency for novel discoveries of safer and highly effective depression treatments. Stingless bee honey (SBH) has been proven to contain a high level of antioxidants compared to other types of honey. This is a comprehensive review of the potential use of SBH as a new candidate for antidepressants from the perspective of the monoamine, inflammatory and neurotrophin hypotheses.

Induction of ICAM1 in Brain Vessels is Implicated in an Early AD Pathogenesis by Modulating Neprilysin

Intercellular adhesion molecule 1 (ICAM1) is a vessel adhesion protein induced during brain vascular inflammation, which could be closely linked with the development of Alzheimer's disease (AD). This study investigated the effect of ICAM1 on amyloid-degrading enzymes (ADEs) in endothelial cells and their potential involvement in inflammation and AD progression. TNF-α treatment increased ICAM1 in human brain microvascular endothelial cells (HBMVECs) but decreased the neprilysin (NEP) protein level. Knock-down of ICAM1 using siRNA enhanced NEP, which increased the degradation of amyloid-β. In the brains of 4-month-old AD transgenic mice (APPswe/PSEN1dE9), there were significantly higher levels of ICAM1 expression and amyloid deposits but lower levels of NEP and insulin-degrading enzymes (IDE), demonstrating an inverse correlation of ICAM1 with NEP and IDE expression. Further studies demonstrated significantly increased GFAP protein levels in the brain, specifically localized near blood vessels, of both TNF-α-injected and 4-month-old AD transgenic mice. Taken together, the induction of ICAM1 in endothelial cells suppresses NEP expression, accelerating the accumulation of amyloid-β in blood vessels. It also enhances leukocyte adhesion to blood vessels stimulating the migration of leukocytes into the brain, subsequently triggering brain inflammation.

Decreased levels of cytokines implicate altered immune response in plasma of moderate-stage Alzheimer's disease patients

Alzheimer's Disease (AD) is a neurodegenerative disease characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. However, increasing evidence suggests that the pathogenesis of the disease is associated with peripheral inflammation. Here, we aimed to determine plasma concentrations of multiple cytokines and chemokines from moderate-stage AD and age-matched controls. Changes in a total of 20 cytokines and chemokines in plasma of moderate-stage AD were evaluated by using quantitative microarray. Six of them, namely MCP-1, MIP-1a, MIP-1b, MMP-9, RANTES, and VEGF, were found to be significantly reduced in moderate-stage AD patients (n = 25) in comparison to age-matched and non-demented controls (n = 25). However, GM-CSF, GRO-α/β/γ, IFN- γ, IL-1α, IL-1β, IL-10, IL-12 p70, IL-13, IL-2, IL- 4, IL-5, IL-6, IL-8, and TNF-α showed no significant differences between the patient and control groups. On the contrary to previous early-stage AD studies that show increased plasma cytokine/chemokine levels, our results indicate that inflammatory plasma molecules are reduced in moderate-stage AD. This finding points out the reduced immune responsiveness, which is known to be directly correlated to the degree of AD.

Bacterial pneumonia and subsequent dementia risk: A nationwide cohort study

BACKGROUND

Bacterial pneumonia is associated with an increased risk of dementia. However, the association between different pathogens of bacterial pneumonia and the risk of dementia remains unclear.

METHODS

Using the Taiwan National Health Insurance Research Database, we recruited 11,712 patients with bacterial pneumonia and 11,120 controls between 1997 and 2012 and followed them up until the end of 2013. A diagnosis of dementia, Alzheimer's disease (AD), vascular dementia (VaD), and unspecified dementia were identified during the follow-up period. Cox regression analyses were performed with adjustments for confounders. Sensitivity analysis was conducted to exclude patients with prodromal dementia.

RESULTS

Patients with bacterial pneumonia were more likely to develop dementia (hazard ratio [HR]: 2.83, 95% confidence interval [CI]: 2.53-3.18), AD (HR: 2.44, 95% CI: 1.65-3.61), VaD (HR: 4.15, 95% CI: 3.20-5.38), and unspecified dementia (HR: 2.62, 95% CI: 2.29-3.00) compared with controls after adjusting for potential confounders. Subgroup pathogen analyses showed that the HR of AD was 3.85 (1.66-8.96) for Hemophilus, and the HR of VaD was 5.40 for Staphylococcus. The risks of dementia and VaD were associated with repeated hospitalization due to bacterial pneumonia in a dose-dependent manner. Sensitivity analyses after exclusion of the first three years or first five years of observation and after exclusion case enrollment before 2010 or 2008 showed consistent findings.

CONCLUSION

Different pathogens are associated with different risks of AD, VaD, and unspecified dementia. Further studies are necessary to investigate the underlying mechanisms of bacterial pneumonia and dementia.

Molecular Signaling Pathway Targeted Therapeutic Potential of Thymoquinone in Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disease with rapid progression. Black cumin (Nigella sativa) is a nutraceutical that has been investigated as a prophylactic and therapeutic agent for this disease due to its ability to prevent or retard the progression of neurodegeneration. Thymoquinone (TQ) is the main bioactive compound isolated from the seeds of black cumin. Several reports have shown that it has promising potential in the prevention and treatment of AD due to its significant antioxidative, anti-inflammatory, and antiapoptotic properties along with several other mechanisms that target the altered signaling pathways due to the disease pathogenesis. In addition, it shows anticholinesterase activity and prevents α-synuclein induced synaptic damage. The aim of this review is to summarize the potential aspects and mechanisms by which TQ imparts its action in AD.

The Role of Exosomes as Mediators of Neuroinflammation in the Pathogenesis and Treatment of Alzheimer’s Disease

Alzheimer’s disease (AD) is a common neurodegenerative disease characterized by progressive dementia. Accumulation of β–amyloid peptide 1–42 and phosphorylation of tau protein in the brain are the two main pathological features of AD. However, comprehensive studies have shown that neuroinflammation also plays a crucial role in the pathogenesis of AD. Neuroinflammation is associated with neuronal death and abnormal protein aggregation and promotes the pathological process of β-amyloid peptide 1–42 and tau protein. The inflammatory components associated with AD include glial cells, complement system, cytokines and chemokines. In recent years, some researchers have focused on exosomes, a type of membrane nano vesicles. Exosomes can transport proteins, lipids, microRNAs and other signaling molecules to participate in a variety of signaling pathways for signal transmission or immune response, affecting the activity of target cells and participating in important pathophysiological processes. Therefore, exosomes play an essential role in intercellular communication and may mediate neuroinflammation to promote the development of AD. This paper reviews the occurrence and development of neuroinflammation and exosomes in AD, providing a deeper understanding of the pathogenesis of AD. Furthermore, the role of exosomes in the pathogenesis and treatment of AD is further described, demonstrating their potential as therapeutic targets for neuroinflammation and AD in the future.

Curcumin Scaffold as a Multifunctional Tool for Alzheimer's Disease Research

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders, which is caused by multi-factors and characterized by two histopathological hallmarks: amyloid-β (Aβ) plaques and neurofibrillary tangles of Tau proteins. Thus, researchers have been devoting tremendous efforts to developing and designing new molecules for the early diagnosis of AD and curative purposes. Curcumin and its scaffold have fluorescent and photochemical properties. Mounting evidence showed that curcumin scaffold had neuroprotective effects on AD such as anti-amyloidogenic, anti-inflammatory, anti-oxidative and metal chelating. In this review, we summarized different curcumin derivatives and analyzed the in vitro and in vivo results in order to exhibit the applications in AD diagnosis, therapeutic monitoring and therapy. The analysis results showed that, although curcumin and its analogues have some disadvantages such as short wavelength and low bioavailability, these shortcomings can be conquered by modifying the structures. Curcumin scaffold still has the potential to be a multifunctional tool for AD research, including AD diagnosis and therapy.

Neuroprotective Potency of Neolignans in Magnolia officinalis Cortex Against Brain Disorders

In recent years, neurological diseases including Alzheimer’s disease, Parkinson’s disease and stroke are one of the main causes of death in the world. At the same time, the incidence of psychiatric disorders including depression and anxiety has been increasing. Accumulating elderly and stressed people suffer from these brain disorders, which is undoubtedly a huge burden on the modern aging society. Neolignans, the main active ingredients in Magnolia officinalis cortex, were reported to have neuroprotective effects. In addition, the key bioactive ingredients of neolignans, magnolol (1) and honokiol (2), were proved to prevent and treat neurological diseases and psychiatric disorders by protecting nerve cells and brain microvascular endothelial cells (BMECs). Furthermore, neolignans played a role in protecting nerve cells via regulation of neuronal function, suppression of neurotoxicity, etc. This review summarizes the neuroprotective effect, primary mechanisms of the leading neolignans and provides new prospects for the treatment of brain disorders in the future.