Promising Intervention Approaches to Potentially Resolve Neuroinflammation And Steroid Hormones Alterations in Alzheimer's Disease and Its Neuropsychiatric Symptoms

Cranberry Extract Ameliorates Diabetic Cognitive Impairment in Rats Via LncRNA GAS-5 Downregulation and Pyroptosis Pathway Inhibition

The pathophysiology of diabetes-induced brain injury involves pyroptosis, an inflammatory programmed cell death. This study aimed to investigate the potential protective effect of cranberry extract (CE) against diabetes-induced brain injury. Type 1 diabetes was induced by intraperitoneal injection of streptozotocin in rats. Brain tissue samples were investigated for biochemical determination of the reduced glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA), and the quantitative RT-PCR for the gene expression of glial cell-derived neurotrophic factor (GDNF), lncRNA GAS-5, and pyroptosis markers. ELISA was used to determine the caspase-1 level and immunohistochemical staining for assessing IL-1β. Prophylactic dosing of the CE in diabetic rats improved cognitive behavior and significantly suppressed MDA concentration, pyroptosis genes expression (gasdermin D and caspase 1), and lncRNA GAS-5. In addition, CE significantly elevated GSH concentration, SOD activity, and gene expression of GDNF and markedly reduced IL-1β positive stained cells score in the brain. Phytochemical characterization of the CE by FT-IR and UPLC-PDA-MS/MS revealed cyanidin arabinoside, procyanidins, quercetin, and isorhamnetin as key components. CE protects against diabetes-induced cognitive dysfunction in rats by targeting redox-related signaling pathways and inducing an anti-inflammatory effect. LncRNA GAS-5 downregulation and pyroptosis pathway inhibition may contribute to its beneficial effects, suggesting its therapeutic potential.

Impact of corticoid receptors on Alzheimer's disease: a neuroendocrine perspective

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that has been strongly associated with changes in corticoid receptor function and HPA axis dysregulation. This review gives an overview of the complex role of GC and MC receptors in AD, especially how chronic exposure to elevated cortisol contributes to hippocampal degeneration, oxidative stress, and cognitive decline. Specific emphasis lies with cortisol, brought to the attention of neurotoxicity, and relates it to Cushing syndrome with chronic hyper-cortisolism simulating cognitive and structural impairments seen in AD. The impact of HPA axis over-activity in AD pathology is presented, demonstrating its contribution to neuro-inflammation and possible utilization as a biomarker for disease progression. This review further includes pharmacological strategies that modulate corticoid receptors for the reduction of GC-induced neurotoxicity and includes selective GR antagonists and MR agonists. Lifestyle modifications, which modulate HPA activity, are the other non-pharmacological approach to managing AD. Finally, novel drugs and interventions targeting the regulation of GC, anti-inflammatory pathways, as well as attenuation of oxidative stress are emerging strategies. Such a strategy implies that it is possible that receptor activity balance can delay or arrest AD progression.

Ozone protects from myocardial ischemia-reperfusion injury via inhibition of the NLRP3 inflammasome

Ischemic heart disease (IHD) is a leading cause of morbidity and mortality worldwide. Myocardial ischemia/reperfusion injury (MIRI) is the primary cause of myocardial injury triggered by post-myocardial infarction reperfusion therapy. Its pathogenesis involves Ca2+ overload, the production of large amounts of oxygen-free radicals, inflammation, and cell necrosis. Growing evidence suggests that the NLRP3 inflammasome significantly contributes to the sterile inflammatory response and pyroptosis in MIRI, linking damage sensing to the initiation and amplification of the inflammatory response. Reportedly, ozone exerts anti-inflammatory and anti-infection effects by activating the antioxidant system. Additional evidence suggests that ozone inhibits NLRP3 inflammasome expression to relieve ischemic injury. In this study, we aimed to explore whether pretreating the myocardium with ozone protects it from MIRI by inhibiting the NLRP3 inflammasome. Rats were subjected to rectal infusion of ozone for 5 consecutive days, followed by ligation of the left anterior descending coronary artery for 30 min and reperfusion for 120 min to induce MIRI. Experimental results were obtained using echocardiography, triphenyltetrazolium chloride and hematoxylin and eosin staining, western blotting, and enzyme-linked immunosorbent assay. The results showed that ozone significantly improved the diastolic function of the heart, reduced the area of myocardial infarction, and decreased the expression levels of NLRP3, pro-caspase-1, ASC, and the secretion of caspase-1, interleukin (IL)-1β, and IL-18. In summary, these findings reveal that ozone pretreatment can alleviate the damage that occurs during MIRI by inhibiting the NLRP3 Inflammasome.

Transcriptome analysis reveals that the injection of mesenchymal stem cells remodels extracellular matrix and complement components of the brain through PI3K/AKT/FOXO1 signaling pathway in a neuroinflammation mouse model

Neurological disorders are often accompanied by neuroinflammatory responses. Our previous research indicated that mesenchymal stem cells (MSCs) suppressed neuroinflammation in the brain. The mechanism of action remains not fully understood. In this study, we analyzed the impact of injected MSCs on the transcriptome in the brains of neuroinflammatory mouse model (NIM) with bioinformatical methods and conducted experimental validation with qPCR and Western blot. The results showed that the expression of extracellular matrix components changed, and the complement cascade was activated in the NIM brains. Injection of MSCs reversed the expression of ECM components and inhibited complement activation. MSCs may promote the improvement of neuronal synaptic function and alter the infiltration of immune cells into the brain. MSCs regulated the PI3K/AKT/Foxo1 signaling pathway. These findings will be very helpful for the development of MSCs-based therapy and the treatment of neuroinflammation-related diseases.

Steroidogenic acute regulatory protein mediated variations of gender-specific sex neurosteroids in Alzheimer's disease: Relevance to hormonal and neuronal imbalance

The steroidogenic acute regulatory (StAR) protein mediates the rate-liming step in neuro/steroid biosynthesis. Multifaceted and delicate changes during aging, disrupting hormonal and neuronal homeostasis, constitute human senescence, an inevitable phenomenon that attributes to increased morbidity and mortality. Aging, along with progressive decreases in bioactive neurosteroids, is the primary risk factor for Alzheimer's disease (AD), which preferentially impacts two-thirds of women and one-third of men. AD is neuropathologically characterized by the accumulation of extracellular amyloid-β and intracellular phosphorylated Tau containing neurofibrillary tangles, resulting in dementia. Postmortem brains pertaining to gender-specific AD patients exhibit varied suppression of StAR and sex neurosteroid levels compared with age-matched cognitively healthy subjects, in which the attenuation of StAR is inversely correlated with the AD pathological markers. Interestingly, retinoid signaling upregulates StAR-motivated neurosteroid biosynthesis and reinstates various neurodegenerative vulnerabilities that promote AD pathogenesis. This review summarizes current understanding of StAR-driven alterations of sex neurosteroids in gender-specific AD risks and provides biochemical and molecular insights into therapeutic interventions for preventing and/or alleviating dementia for healthy aging.

Frontiers and hotspots evolution between air pollution and Alzheimer's disease: A bibliometric analysis from 2013 to 2023

In recent years, the study of air pollution has received increasing attention from researchers, but a summary of Alzheimer's disease (AD) and air pollution is missed. Through combing the documents in the core dataset of Web of Science, this study analyzes current research based on specific keywords. CiteSpace and VOSviewer perform statistical analysis of measurement metrics to visualize a network of relevant content elements. The research devotes discussion to the relationship between air pollution and AD. Keyword hotspots include AD, children, oxidative stress, and system inflammation. Overall, 304 documents on air pollution and AD from 2013 to 2023 were retrieved from Web of Science. One hundred twenty-two journals published relevant articles, and the number of articles has increased gradually since the past decade. Research and development in AD and air pollution are progressing rapidly, but there is still a need for more connections with multidisciplinary technologies to explore cutting-edge hotspots.

The relationship between gender differences in dietary habits, neuroinflammation, and Alzheimer's disease

Neurocognitive decline is one of the foremost dire issues in medicine today. The mechanisms by which dementia pathogenesis ensues are complicated and multifactorial, particularly in the case of Alzheimer's disease (AD). One irrefutable, yet unexplained factor is the gender disparity in AD, in which women are disproportionately affected by AD, both in the rate and severity of the disease. Examining the multifaceted contributing causes along with unique gender dynamics in modifiable risk factors, such as diet, may lend some insight into why this disparity exists and potential paths forward. The aim of this brief narrative review is to summarize the current literature of gender differences in dietary habits and how they may relate to neuroinflammatory states that contribute to AD pathogenesis. As such, the interplay between diet, hormones, and inflammation will be discussed, along with potential interventions to inform care practices.

Identification of blood metabolites associated with risk of Alzheimer's disease by integrating genomics and metabolomics data

Specific metabolites have been reported to be potentially associated with Alzheimer's disease (AD) risk. However, the comprehensive understanding of roles of metabolite biomarkers in AD etiology remains elusive. We performed a large AD metabolome-wide association study (MWAS) by developing blood metabolite genetic prediction models. We evaluated associations between genetically predicted levels of metabolites and AD risk in 39,106 clinically diagnosed AD cases, 46,828 proxy AD and related dementia (proxy-ADD) cases, and 401,577 controls. We further conducted analyses to determine microbiome features associated with the detected metabolites and characterize associations between predicted microbiome feature levels and AD risk. We identified fourteen metabolites showing an association with AD risk. Five microbiome features were further identified to be potentially related to associations of five of the metabolites. Our study provides new insights into the etiology of AD that involves blood metabolites and gut microbiome, which warrants further investigation.

The Mito-Hormetic Mechanisms of Ozone in the Clearance of SARS-CoV2 and in the COVID-19 Therapy

An increasing body of evidence in the literature is reporting the feasibility of using medical ozone as a possible alternative and adjuvant treatment for COVID-19 patients, significantly reducing hospitalization time, pro-inflammatory indicators, and coagulation markers and improving blood oxygenation parameters. In addition to the well-described ability of medical ozone in counteracting oxidative stress through the upregulation of the main anti-oxidant and scavenging enzymes, oxygen–ozone (O₂–O₃) therapy has also proved effective in reducing chronic inflammation and the occurrence of immune thrombosis, two key players involved in COVID-19 exacerbation and severity. As chronic inflammation and oxidative stress are also reported to be among the main drivers of the long sequelae of SARS-CoV2 infection, a rising number of studies is investigating the potential of O₂–O₃ therapy to reduce and/or prevent the wide range of post-COVID (or PASC)-related disorders. This narrative review aims to describe the molecular mechanisms through which medical ozone acts, to summarize the clinical evidence on the use of O₂–O₃ therapy as an alternative and adjuvant COVID-19 treatment, and to discuss the emerging potential of this approach in the context of PASC symptoms, thus offering new insights into effective and safe nonantiviral therapies for the fighting of this devastating pandemic.

Is Dutasteride a Therapeutic Alternative for Amyotrophic Lateral Sclerosis?

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is characterized by the loss of upper and lower motor neurons (MNs) in the cerebral cortex, brainstem and spinal cord, with consequent weakness, atrophy and the progressive paralysis of all muscles. There is currently no medical cure, and riluzole and edaravone are the only two known approved drugs for treating this condition. However, they have limited efficacy, and hence there is a need to find new molecules. Dutasteride, a dual inhibitor of type 1 and type 2 5α-reductase (5AR) enzymes, the therapeutic purposes of which, to date, are the treatment of benign prostatic hyperplasia and androgenic alopecia, shows great anti-ALS properties by the molecular-topology methodology. Based on this evidence, this review aims to assess the effects of dutasteride on testosterone (T), progesterone (PROG) and 17β-estradiol (17BE) as a therapeutic alternative for the clinical improvement of ALS, based on the hormonal, metabolic and molecular pathways related to the pathogenesis of the disease. According to the evidence found, dutasteride shows great neuroprotective, antioxidant and anti-inflammatory effects. It also appears effective against glutamate toxicity, and it is capable of restoring altered dopamine activity (DA). These effects are achieved both directly and through steroid hormones. Therefore, dutasteride seems to be a promising molecule for the treatment of ALS, although clinical studies are required for confirmation.

Therapeutic Treatment of Superoxide Dismutase 1 (G93A) Amyotrophic Lateral Sclerosis Model Mice with Medical Ozone Decelerates Trigeminal Motor Neuron Degeneration, Attenuates Microglial Proliferation, and Preserves Monocyte Levels in Mesenteric Lymph Nodes

Amyotrophic lateral sclerosis (ALS) is an incurable and lethal neurodegenerative disease in which progressive motor neuron loss and associated inflammation represent major pathology hallmarks. Both the prevention of neuronal loss and neuro-destructive inflammation are still unmet challenges. Medical ozone, an ozonized oxygen mixture (O₃/O₂), has been shown to elicit profound immunomodulatory effects in peripheral organs, and beneficial effects in the aging brain. We investigated, in a preclinical drug testing approach, the therapeutic potential of a five-day O₃/O₂i.p. treatment regime at the beginning of the symptomatic disease phase in the superoxide dismutase (SOD1^G93A) ALS mouse model. Clinical assessment of SOD1^G93A mice revealed no benefit of medical ozone treatment over sham with respect to gross body weight, motor performance, disease duration, or survival. In the brainstem of end stage SOD1^G93A mice, however, neurodegeneration was found decelerated, and SOD1-related vacuolization was reduced in the motor trigeminal nucleus in the O₃/O₂ treatment group when compared to sham-treated mice. In addition, microglia proliferation was less pronounced in the brainstem, while the hypertrophy of astroglia remained largely unaffected. Finally, monocyte numbers were reduced in the blood, spleen, and mesenteric lymph nodes at postnatal day 60 in SOD1^G93A mice. A further decrease in monocyte numbers seen in mesenteric lymph nodes from sham-treated SOD1^G93A mice at an advanced disease stage, however, was prevented by medical ozone treatment. Collectively, our study revealed a select neuroprotective and possibly anti-inflammatory capacity for medical ozone when applied as a therapeutic agent in SOD1^G93A ALS mice.

HMGB1 plays an important role in pyroptosis induced blood brain barrier breakdown in diabetes-associated cognitive decline

Diabetes mellitus increases the risk of dementia, and evidence suggests hyperglycemia is a key contributor to neurodegeneration. However, our understanding of diabetes-associated cognitive decline, an important complication of diabetes mellitus, is lacking and the underlying mechanism is unclear. Blood brain barrier (BBB) breakdown is a possible cause of dementia in diabetes mellitus and Alzheimer's disease. Accumulating evidence shows BBB dysfunction caused by hyperglycemia contributes to cognitive decline. A specific type of inflammatory programmed cell death, called pyroptosis, has potential as a therapeutic target for BBB-associated diseases. Potential inducers of pyroptosis include inflammasomes such as NLRP3, whose activation relies on damage-associated molecular patterns. High mobility group box 1 (HMGB1) is a highly conserved, ubiquitous protein found in most cell types, and acts as a damage-associated molecular pattern when released from the nucleus. We propose that HMGB1 influences vascular inflammation by activating the NLRP3 inflammasome and thereby initiating pyroptosis in vascular cells. Moreover, HMGB1 plays a pivotal role in the pathogenesis of diabetes mellitus and diabetic complications. Here, we review the role of HMGB1 in BBB dysfunction induced by hyperglycemia and propose that HMGB1 is a promising therapeutic target for countering diabetes-associated cognitive decline.

Trilobatin Alleviates Cognitive Deficits and Pathologies in an Alzheimer's Disease Mouse Model

Alzheimer's disease (AD) is the most common neurodegenerative disease nowadays that causes memory impairments. It is characterized by extracellular aggregates of amyloid-beta (Aβ), intracellular aggregates of hyperphosphorylated Tau (p-Tau), and other pathological features. Trilobatin (TLB), a natural flavonoid compound isolated from Lithocarpuspolystachyus Rehd., has emerged as a neuroprotective agent. However, the effects and mechanisms of TLB on Alzheimer's disease (AD) remain unclear. In this research, different doses of TLB were orally introduced to 3×FAD AD model mice. The pathology, memory performance, and Toll-like receptor 4- (TLR4-) dependent inflammatory pathway protein level were assessed. Here, we show that TLB oral treatment protected 3×FAD AD model mice against the Aβ burden, neuroinflammation, Tau hyperphosphorylation, synaptic degeneration, hippocampal neuronal loss, and memory impairment. The TLR4, a pattern recognition immune receptor, has been implicated in neurodegenerative disease-related neuroinflammation. We found that TLB suppressed glial activation by inhibiting the TLR4-MYD88-NFκB pathway, which leads to the inflammatory factor TNF-α, IL-1β, and IL-6 reduction. Our study shows that TLR4 might be a key target of TLB in AD treatment and suggests a multifaceted target of TLB in halting AD. Taken together, our findings suggest a potential therapeutic effect of TLB in AD treatment.

Blood-Based Biomarkers of Neuroinflammation in Alzheimer's Disease: A Central Role for Periphery?

Neuroinflammation represents a central feature in the development of Alzheimer’s disease (AD). The resident innate immune cells of the brain are the principal players in neuroinflammation, and their activation leads to a defensive response aimed at promoting β-amyloid (Aβ) clearance. However, it is now widely accepted that the peripheral immune system—by virtue of a dysfunctional blood–brain barrier (BBB)—is involved in the pathogenesis and progression of AD; microglial and astrocytic activation leads to the release of chemokines able to recruit peripheral immune cells into the central nervous system (CNS); at the same time, cytokines released by peripheral cells are able to cross the BBB and act upon glial cells, modifying their phenotype. To successfully fight this neurodegenerative disorder, accurate and sensitive biomarkers are required to be used for implementing an early diagnosis, monitoring the disease progression and treatment effectiveness. Interestingly, as a result of the bidirectional communication between the brain and the periphery, the blood compartment ends up reflecting several pathological changes occurring in the AD brain and can represent an accessible source for such biomarkers. In this review, we provide an overview on some of the most promising peripheral biomarkers of neuroinflammation, discussing their pathogenic role in AD.