Chronic effects of inflammation on tauopathies

Elevated C-Reactive Protein in Older Men With Chronic Pain: Association With Plasma Amyloid Levels and Hippocampal Volume

BACKGROUND

Chronic pain leads to tau accumulation and hippocampal atrophy, which may be moderated through inflammation. In older men, we examined associations of chronic pain with Alzheimer's disease (AD)-related plasma biomarkers and hippocampal volume as moderated by systemic inflammation.

METHODS

Participants were men without dementia. Chronic pain was defined as moderate-to-severe pain in 2+ study waves at average ages 56, 62, and 68. At age 68, we measured plasma amyloid-beta (Aβ42, n = 871), Aβ40 (n = 887), total tau (t-tau, n = 841), and neurofilament light chain (NfL, n = 915), and serum high-sensitivity C-reactive protein (hs-CRP, n = 968), a marker of systemic inflammation. A subgroup underwent structural MRI to measure hippocampal volume (n = 385). Analyses adjusted for medical morbidities, depressive symptoms, and opioid use.

RESULTS

Chronic pain was related to higher Aβ40 (β = 0.25, p = .009), but hs-CRP was unrelated to AD-related biomarkers (ps > .05). There was a significant interaction such that older men with both chronic pain and higher levels of hs-CRP had higher levels of Aβ42 (β = 0.36, p = .001) and Aβ40 (β = 0.29, p = .003). Chronic pain and hs-CRP did not interact to predict levels of Aβ42/Aβ40, t-tau, or NfL. Furthermore, there were significant interactions such that Aβ42 and Aβ40 were associated with lower hippocampal volume, particularly when levels of hs-CRP were elevated (hs-CRP × Aβ42: β = -0.19, p = .002; hs-CRP × Aβ40: β = -0.21, p = .001), regardless of chronic pain status.

CONCLUSIONS

Chronic pain was associated with higher plasma Aβ, especially when hs-CRP was also elevated. Higher hs-CRP and Aβ levels were both related to smaller hippocampal volumes. Chronic pain, when accompanied by systemic inflammation, may elevate the risk of neurodegeneration in AD-vulnerable regions.

A randomized, placebo-controlled trial of purified anthocyanins on cognitive function in individuals at elevated risk for dementia: Analysis of inflammatory biomarkers toward personalized interventions

BACKGROUND

Dementia poses a significant global health challenge. Anthocyanins neutralize free radicals, modulate signaling pathways, inhibit pro-inflammatory genes, and suppress cytokine production and may thus have positive cognitive effects in people at increased risk of dementia. We aim to investigate the effects of purified anthocyanins on cognitive function in people at increased risk of dementia according to their inflammation status based on blood-based inflammatory biomarkers.

METHODS

This is a secondary analysis of a 24-week randomized, double-blind, placebo-controlled trial. Cluster analysis was performed to categorize two groups based on their individual inflammatory biomarker profile using multiplex sandwich ELISA for the quantitative measurement of cytokines. Descriptive statistics and longitudinal models assessed cognitive outcomes. The primary comparison was the group difference at week 24 based on a modified intention-to-treat analysis.

RESULTS

Cluster analysis revealed two distinct inflammatory biomarker profiles. In Cluster 1 (high levels of inflammation biomarkers), anthocyanin treatment showed a statistically significant improvement on cognitive function compared to placebo at 24 weeks. No significant differences were observed in Cluster 2 (low levels of inflammation biomarkers). The demographic characteristics, cognitive scores, and biomarker distributions were similar between treatment groups at baseline. However, cluster 1 exhibited higher BMI, diabetes prevalence, medication usage, and lower HDL cholesterol levels.

CONCLUSION

Individuals with elevated levels of inflammation markers benefited from anthocyanin treatment to enhance cognitive performance, whereas those with lower levels did not. The anti-inflammatory and antioxidant properties of anthocyanins make them a promising intervention, and future prospective trials in people with increased inflammation are warranted.

Association between autoimmune diseases and Alzheimer's disease: Analysis using big data tools

OBJECTIVE

The objective is to analyze the prevalence of Alzheimer's disease in patients with and without a diagnosis of different autoimmune diseases and the possible association between both pathologies.

PATIENTS AND METHODS

A multicenter, retrospective, cohort study was conducted to study the prevalence of Alzheimer's disease among patients diagnosed with various autoimmune diseases compared to the general population. Data from electronic medical records from the Castilla-La Mancha healthcare system were analyzed using Natural Language Processing through the Savana Manager® artificial intelligence clinical platform. A total of 1,028,356 patients were analyzed, including 28,920 individuals with Alzheimer's disease and 999,436 control patients.

RESULTS

Out of the 12 autoimmune diseases analyzed, 5 showed a significant association with Alzheimer's disease with p < 0.05. Myasthenia gravis had an increased prevalence of AD with OR 1.49 (95% CI 1.11-2), systemic lupus erythematosus with OR 2.42 (95% CI 2.02-2.88), rheumatoid arthritis with OR 1.38 (95% CI 1.24-1.54), polymyalgia rheumatica with OR 2.01 (95% CI 1.08-2.23), and pernicious anemia with OR 2.06 (95% CI 1.59-2.66). The remaining autoimmune diseases analyzed did not show a higher prevalence of Alzheimer's disease compared to the general population.

CONCLUSIONS

There may be an association between certain systemic autoimmune diseases and Alzheimer's disease. Further studies are needed to confirm our findings, establish causality, and explore the underlying mechanisms of this association.

Proteolysis of tau by granzyme A in tauopathies generates fragments that are aggregation prone

Tauopathies, including Alzheimer's disease, corticobasal degeneration and progressive supranuclear palsy, are characterised by the aggregation of tau into insoluble neurofibrillary tangles in the brain. Tau is subject to a range of post-translational modifications, including proteolysis, that can promote its aggregation. Neuroinflammation is a hallmark of tauopathies and evidence is growing for a role of CD8+ T cells in disease pathogenesis. CD8+ T cells release granzyme proteases but what role these proteases play in neuronal dysfunction is currently lacking. Here, we identified that granzyme A (GzmA) is present in brain tissue and proteolytically cleaves tau. Mass spectrometric analysis of tau fragments produced on digestion of tau with GzmA identified three cleavage sites at R194-S195, R209-S210 and K240-S241. Mutation of the critical Arg or Lys residues at the cleavage sites in tau or chemical inhibition of GzmA blocked the proteolysis of tau by GzmA. Development of a semi-targeted mass spectrometry approach identified peptides in tauopathy brain tissue corresponding to proteolysis by GzmA at R209-S210 and K240-S241 in tau. When expressed in cells the GzmA-cleaved C-terminal fragments of tau were highly phosphorylated and aggregated upon incubation of the cells with tauopathy brain seed. The C-terminal fragment tau195-441 was able to transfer between cells and promote aggregation of tau in acceptor cells, indicating the propensity for such tau fragments to propagate between cells. Collectively, these results raise the possibility that GzmA, released from infiltrating cytotoxic CD8+ T cells, proteolytically cleaves tau into fragments that may contribute to its pathological properties in tauopathies.

The impact of physical exercise on neuroinflammation mechanism in Alzheimer's disease

Introduction

Alzheimer's disease (AD), a major cause of dementia globally, imposes significant societal and personal costs. This review explores the efficacy of physical exercise as a non-pharmacological intervention to mitigate the impacts of AD.

Methods

This review draws on recent studies that investigate the effects of physical exercise on neuroinflammation and neuronal enhancement in individuals with AD.

Results

Consistent physical exercise alters neuroinflammatory pathways, enhances cognitive functions, and bolsters brain health among AD patients. It favorably influences the activation states of microglia and astrocytes, fortifies the integrity of the blood-brain barrier, and attenuates gut inflammation associated with AD. These changes are associated with substantial improvements in cognitive performance and brain health indicators.

Discussion

The findings underscore the potential of integrating physical exercise into comprehensive AD management strategies. Emphasizing the necessity for further research, this review advocates for the refinement of exercise regimens to maximize their enduring benefits in decelerating the progression of AD.

Neurodegenerative diseases and catechins: (-)-epigallocatechin-3-gallate is a modulator of chronic neuroinflammation and oxidative stress

Catechins, a class of phytochemicals found in various fruits and tea leaves, have garnered attention for their diverse health-promoting properties, including their potential in combating neurodegenerative diseases. Among these catechins, (-)-epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, has emerged as a promising therapeutic agent due to its potent antioxidant and anti-inflammatory effects. Chronic neuroinflammation and oxidative stress are key pathological mechanisms in neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). EGCG has neuroprotective efficacy due to scavenging free radicals, reducing oxidative stress and attenuating neuroinflammatory processes. This review discusses the molecular mechanisms of EGCG's anti-oxidative stress and chronic neuroinflammation, emphasizing its effects on autoimmune responses, neuroimmune system interactions, and focusing on the related effects on AD and PD. By elucidating EGCG's mechanisms of action and its impact on neurodegenerative processes, this review underscores the potential of EGCG as a therapeutic intervention for AD, PD, and possibly other neurodegenerative diseases. Overall, EGCG emerges as a promising natural compound for combating chronic neuroinflammation and oxidative stress, offering novel avenues for neuroprotective strategies in the treatment of neurodegenerative disorders.

Alzheimer's disease genetic pathways impact cerebrospinal fluid biomarkers and imaging endophenotypes in non-demented individuals

INTRODUCTION

Unraveling how Alzheimer's disease (AD) genetic risk is related to neuropathological heterogeneity, and whether this occurs through specific biological pathways, is a key step toward precision medicine.

METHODS

We computed pathway-specific genetic risk scores (GRSs) in non-demented individuals and investigated how AD risk variants predict cerebrospinal fluid (CSF) and imaging biomarkers reflecting AD pathology, cardiovascular, white matter integrity, and brain connectivity.

RESULTS

CSF amyloidbeta and phosphorylated tau were related to most GRSs. Inflammatory pathways were associated with cerebrovascular disease, whereas quantitative measures of white matter lesion and microstructure integrity were predicted by clearance and migration pathways. Functional connectivity alterations were related to genetic variants involved in signal transduction and synaptic communication.

DISCUSSION

This study reveals distinct genetic risk profiles in association with specific pathophysiological aspects in predementia stages of AD, unraveling the biological substrates of the heterogeneity of AD-associated endophenotypes and promoting a step forward in disease understanding and development of personalized therapies.

HIGHLIGHTS

Polygenic risk for Alzheimer's disease encompasses six biological pathways that can be quantified with pathway-specific genetic risk scores, and differentially relate to cerebrospinal fluid and imaging biomarkers. Inflammatory pathways are mostly related to cerebrovascular burden. White matter health is associated with pathways of clearance and membrane integrity, whereas functional connectivity measures are related to signal transduction and synaptic communication pathways.

Association of Exposure to Heavy Metal Mixtures with Systemic Immune-Inflammation Index Among US Adults in NHANES 2011-2016

In reality, people are often co-exposed to multiple heavy metals; however, current research has focused on the association between individual heavy metals and inflammation. Therefore, it is more relevant to explore the combined effects of multiple heavy metal exposure on inflammation. The study included data from the National Health and Nutrition Examination Survey (NHANES), 2011-2016. The systemic immune-inflammation index (SII) was used to reflect systemic immune-inflammation status. In this study, single variable models were used to assess the linear and non-linear relationships between single heavy metal exposures and SII. To analyze the combined effect of mixed heavy metals exposure on SII, we constructed three statistical models, including weighted quantile sum (WQS) regression, quantile-based g computation (qgcomp), and Bayesian kernel machine regression (BKMR). The single-exposure analysis found positive associations between multiple heavy metals and SII, while mercury in blood was negatively associated with SII, and U-shaped correlations were observed between blood lead, urine barium and strontium, and SII. In the WQS model, SII increased significantly with increasing concentrations of mixed heavy metals, while consistent results in the qgcomp model, but not statistically significant. In the BKMR model, exposure to heavy metal mixtures was positively associated with SII, with mercury, cadmium, and cobalt in urine contributing the most to the mixed exposure. In addition, synergistic and antagonistic effects between heavy metals on increasing SII were found in our study. In summary, our results reveal that combined exposure to multiple heavy metals is positively associated with SII in the US adults.

Integrating network pharmacology and experimental verification to reveal the anti-inflammatory ingredients and molecular mechanism of pycnogenol

Introduction: Pycnogenol (PYC), a standardized extract from French maritime pine, has traditionally been used to treat inflammation. However, its primary active components and their mechanisms of action have not yet been determined. Methods: This study employed UPLC-MS/MS (Ultra-high performance liquid chromatography-tandem mass spectrometry) and network pharmacology to identify the potential active components of PYC and elucidate their anti-inflammatory mechanisms by cell experiments. Results: 768 PYC compounds were identified and 19 anti-inflammatory compounds were screened with 85 target proteins directly involved in the inflammation. PPI (protein-protein interaction) analysis identified IL6, TNF, MMP9, IL1B, AKT1, IFNG, CXCL8, NFKB1, CCL2, IL10, and PTGS2 as core targets. KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis suggested that the compound in PYC might exert anti-inflammatory effects through the IL17 and TNF signal pathways. Cell experiments determined that PYC treatment can reduce the expression of IL6 and IL1β to relieve inflammation in LPS (lipopolysaccharide)-induced BV2 cells. Conclusion: PYC could affect inflammation via multi-components, -targets, and -mechanisms.

Neuroinflammation in Alzheimer's disease: insights from peripheral immune cells

Alzheimer's disease (AD) is a serious brain disorder characterized by the presence of beta-amyloid plaques, tau pathology, inflammation, neurodegeneration, and cerebrovascular dysfunction. The presence of chronic neuroinflammation, breaches in the blood-brain barrier (BBB), and increased levels of inflammatory mediators are central to the pathogenesis of AD. These factors promote the penetration of immune cells into the brain, potentially exacerbating clinical symptoms and neuronal death in AD patients. While microglia, the resident immune cells of the central nervous system (CNS), play a crucial role in AD, recent evidence suggests the infiltration of cerebral vessels and parenchyma by peripheral immune cells, including neutrophils, T lymphocytes, B lymphocytes, NK cells, and monocytes in AD. These cells participate in the regulation of immunity and inflammation, which is expected to play a huge role in future immunotherapy. Given the crucial role of peripheral immune cells in AD, this article seeks to offer a comprehensive overview of their contributions to neuroinflammation in the disease. Understanding the role of these cells in the neuroinflammatory response is vital for developing new diagnostic markers and therapeutic targets to enhance the diagnosis and treatment of AD patients.

Association between the systemic immune-inflammation index and sarcopenia: a systematic review and meta-analysis

BACKGROUND

Sarcopenia is associated with increased morbidity and mortality. The systemic immune-inflammation index (SII) has been correlated to a variety of disorders. The present study conducted a systematic review and meta-analysis to investigate the relationship between SII and sarcopenia.

METHODS

A literature search was performed in Web of Science, PubMed, Embase, Cochrane Library, CINAHL, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wanfang Database, and VIP Chinese Science and Technology Database, from inception to March 2024. Then, the literature quality was assessed. After the heterogeneity test, a random effects or fixed effects model was applied to establish the forest plot, and investigate the relationship between SII and sarcopenia. Then, the sensitivity analysis and publication bias were examined.

RESULTS

Nine articles, which included 18,634 adults, were analyzed. Sarcopenic adults had higher SII levels, when compared to non-sarcopenic adults (standardized mean difference [SMD] = 0.66, 95% confidence interval [CI] = 0.22 - 0.19, p = 0.003). The high SII level was associated to the increased risk of sarcopenia (odds ratio = 1.52, 95% CI = 1.09-2.13, p = 0.01). In addition, the subgroup analysis revealed that the SII levels were higher in the sarcopenic group, when compared to the non-sarcopenic group, in elderly adults, as well as in adults with or without gastrointestinal disorders. The analysis was robust with a low risk of publication bias.

CONCLUSIONS

SII is closely associated to sarcopenia. Sarcopenic adults had elevated SII levels. The high SII level increased the risk of sarcopenia. Large scale multi-center prospective studies are required to validate these study findings.

mTBI Biological Biomarkers as Predictors of Postconcussion Syndrome-Review

Postconcussion syndrome (PCS) is one of the leading complications that may appear in patients after mild head trauma. Every day, thousands of people, regardless of age, gender, and race, are diagnosed in emergency departments due to head injuries. Traumatic Brain Injury (TBI) is a significant public health problem, impacting an estimated 1.5 million people in the United States and up to 69 million people worldwide each year, with 80% of these cases being mild. An analysis of the available research and a systematic review were conducted to search for a solution to predicting the occurrence of postconcussion syndrome. Particular biomarkers that can be examined upon admission to the emergency department after head injury were found as possible predictive factors of PCS development. Setting one unequivocal definition of PCS is still a challenge that causes inconsistent results. Neuron Specific Enolase (NSE), Glial Fibrillary Acidic Protein (GFAP), Ubiquitin C-terminal Hydrolase-L1 (UCH-L1), Serum Protein 100 B (s100B), and tau protein are found to be the best predictors of PCS development. The presence of all mentioned biomarkers is confirmed in severe TBI. All mentioned biomarkers are used as predictors of PCS. A combined examination of NSE, GFAP, UCH-1, S100B, and tau protein should be performed to detect mTBI and predict the development of PCS.

Cell redistribution of G quadruplex-structured DNA is associated with morphological changes of nuclei and nucleoli in neurons during tau pathology progression

While the double helical structure has long been its iconic representation, DNA is structurally dynamic and can adopt alternative secondary configurations. Specifically, guanine-rich DNA sequences can fold in guanine quadruplexes (G4) structures. These G4 play pivotal roles as regulators of gene expression and genomic stability, and influence protein homeostasis. Despite their significance, the association of G4 with neurodegenerative diseases such as Alzheimer's disease (AD) has been underappreciated. Recent findings have identified DNA sequences predicted to form G4 in sarkosyl-insoluble aggregates from AD brains, questioning the involvement of G4-structured DNA (G4 DNA) in the pathology. Using immunofluorescence coupled to confocal microscopy analysis we investigated the impact of tau pathology, a hallmark of tauopathies including AD, on the distribution of G4 DNA in murine neurons and its relevance to AD brains. In healthy neurons, G4 DNA is detected in nuclei with a notable presence in nucleoli. However, in a transgenic mouse model of tau pathology (THY-Tau22), early stages of the disease exhibit an impairment in the nuclear distribution of G4 DNA. In addition, G4 DNA accumulates in the cytoplasm of neurons exhibiting oligomerized tau and oxidative DNA damage. This altered distribution persists in the later stage of the pathology when larger tau aggregates are present. Still cytoplasmic deposition of G4 DNA does not appear to be a critical factor in the tau aggregation process. Similar patterns are observed in neurons from the AD cortex. Furthermore, the disturbance in G4 DNA distribution is associated with various changes in the size of neuronal nuclei and nucleoli, indicative of responses to stress and the activation of pro-survival mechanisms. Our results shed light on a significant impact of tau pathology on the dynamics of G4 DNA and on nuclear and nucleolar mechanobiology in neurons. These findings reveal new dimensions in the etiopathogenesis of tauopathies.

Top 100 most-cited articles on tau protein: a bibliometric analysis and evidence mapping

Background

Tau, a microtubule-associated protein extensively distributed within the central nervous system (CNS), exhibits close associations with various neurodegenerative disorders. Here, we aimed to conduct a qualitative and quantitative bibliometric study of the top 100 most-cited publications on tau protein and reveal the current research hotspots and future perspectives.

Methods

The relevant literature was retrieved from the Web of Science Core Collection. CiteSpace (v6.2.R4) and VOSviewer (1.6.19) were adopted for bibliometric analysis with statistical and visual analysis.

Results

Citations per article ranged from 615 to 3,123, with a median number of 765.5 times. "Neuroscience" emerged as the most extensively researched subject in this field. The USA has emerged as the leading country, with a publication record (n = 65), total citations (n = 66,543), strong centrality (0.29), and extensive international collaborations. Harvard University (n = 11) and the University of California, San Francisco (n = 11) were the top two institutions in terms of publications. Neuron dominated with 13 articles in the 37 high-quality journals. M. Goedert from the MRC Laboratory of Molecular Biology was the most productive (n = 9) and top co-cited (n = 179) author. The most frequently studied keywords were Alzheimer's disease (n = 38). Future research is anticipated to intensify its focus on the pathogenesis of various tau-related diseases, emphasizing the phosphorylation and structural alterations of tau protein, particularly in Alzheimer's disease.

Conclusion

The pathogenesis of various tau-related diseases, including the phosphorylation and structural alterations of the tau protein, will be the primary focus of future research, with particular emphasis on Alzheimer's disease as a central area of investigation.

Hotspots and trends of microglia in Alzheimer's disease: a bibliometric analysis during 2000-2022

BACKGROUND

Alzheimer's disease is one common type of dementia. Numerous studies have suggested a correlation between Alzheimer's disease and inflammation. Microglia mainly participate in the inflammatory response in the brain. Currently, ample evidence has shown that microglia are closely related to the occurrence and development of Alzheimer's disease.

OBJECTIVE

We opted for bibliometric analysis to comprehensively summarize the advancements in the study of microglia in Alzheimer's disease, aiming to provide researchers with current trends and future research directions.

METHODS

All articles and reviews pertaining to microglia in Alzheimer's disease from 2000 to 2022 were downloaded through Web of Science Core Collection. The results were subjected to bibliometric analysis using VOSviewer 1.6.18 and CiteSpace 6.1 R2.

RESULTS

Overall, 7449 publications were included. The number of publications was increasing yearly. The United States has published the most publications. Harvard Medical School has published the most papers of all institutions. Journal of Alzheimer's Disease and Journal of Neuroscience were the journals with the most studies and the most commonly cited, respectively. Mt Heneka is the author with the highest productivity and co-citation. After analysis, the most common keywords are neuroinflammation, amyloid-beta, inflammation, neurodegeneration. Gut microbiota, extracellular vesicle, dysfunction and meta-analysis are the hotspots of research at the present stage and are likely to continue.

CONCLUSION

NLRP3 inflammasome, TREM2, gut microbiota, mitochondrial dysfunction, exosomes are research hotspots. The relationship between microglia-mediated neuroinflammation and Alzheimer's disease have been the focus of current research and the development trend of future research.

Frequent Alzheimer's disease neuropathological change in patients with glioblastoma

Background

The incidence of brain cancer and neurodegenerative diseases is increasing with a demographic shift towards aging populations. Biological parallels have been observed between glioblastoma and Alzheimer's disease (AD), which converge on accelerated brain aging. Here, we aimed to map the cooccurrence of AD neuropathological change (ADNC) in the tumor-adjacent cortex of patients with glioblastoma.

Methods

Immunohistochemical screening of AD markers amyloid beta (Abeta), amyloid precursor protein (APP), and hyperphosphorylated tau (pTau) was conducted in 420 tumor samples of 205 patients. For each cortex area, we quantified ADNC, neurons, tumor cells, and microglia.

Results

Fifty-two percent of patients (N = 106/205) showed ADNC (Abeta and pTau, Abeta or pTau) in the tumor-adjacent cortex, with histological patterns widely consistent with AD. ADNC was positively correlated with patient age and varied spatially according to Thal phases and Braak stages. It decreased with increasing tumor cell infiltration (P < .0001) and was independent of frequent expression of APP in neuronal cell bodies (N = 182/205) and in tumor necrosis-related axonal spheroids (N = 195/205; P = .46). Microglia response was most present in tumor cell infiltration plus ADNC, being further modulated by patient age and sex. ADNC did not impact patient survival in the present cohort.

Conclusions

Our findings highlight the frequent presence of ADNC in the glioblastoma vicinity, which was linked to patient age and tumor location. The cooccurrence of AD and glioblastoma seemed stochastic without clear spatial relation. ADNC did not impact patient survival in our cohort.

Modulating microbiome-immune axis in the deployment-related chronic diseases of Veterans: report of an expert meeting

The present report summarizes the United States Department of Veterans Affairs (VA) field-based meeting titled "Modulating microbiome-immune axis in the deployment-related chronic diseases of Veterans." Our Veteran patient population experiences a high incidence of service-related chronic physical and mental health problems, such as infection, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), various forms of hematological and non-hematological malignancies, neurologic conditions, end-stage organ failure, requiring transplantation, and posttraumatic stress disorder (PTSD). We report the views of a group of scientists who focus on the current state of scientific knowledge elucidating the mechanisms underlying the aforementioned disorders, novel therapeutic targets, and development of new approaches for clinical intervention. In conclusion, we dovetailed on four research areas of interest: 1) microbiome interaction with immune cells after hematopoietic cell and/or solid organ transplantation, graft-versus-host disease (GVHD) and graft rejection, 2) intestinal inflammation and its modification in IBD and cancer, 3) microbiome-neuron-immunity interplay in mental and physical health, and 4) microbiome-micronutrient-immune interactions during homeostasis and infectious diseases. At this VA field-based meeting, we proposed to explore a multi-disciplinary, multi-institutional, collaborative strategy to initiate a roadmap, specifically focusing on host microbiome-immune interactions among those with service-related chronic diseases to potentially identify novel and translatable therapeutic targets.

4R-Tau seeding activity unravels molecular subtypes in patients with Progressive Supranuclear Palsy

Progressive Supranuclear palsy (PSP) is a 4-repeat (4-R) tauopathy. We hypothesized that the molecular diversity of tau could explain the heterogeneity seen in PSP disease progression. To test this hypothesis, we performed an extensive biochemical characterisation of the high molecular weight tau species (HMW-Tau) in 20 different brain regions of 25 PSP patients. We found a correlation between the HMW-Tau species and tau seeding capacity in the primary motor cortex, where we confirmed that an elevated 4R-Tau seeding activity correlates with a shorter disease duration. To identify factors that contribute to these differences, we performed proteomic and spatial transcriptomic analysis that revealed key mechanistic pathways, in particular those involving the immune system, that defined patients demonstrating high and low tau seeding capacity. These observations suggest that differences in the tau seeding activity may contribute to the considerable heterogeneity seen in disease progression of patients suffering from PSP.

A how-to guide for a precision medicine approach to the diagnosis and treatment of Alzheimer's disease

Article purpose

The clinical approach to Alzheimer's disease (AD) is challenging, particularly in high-functioning individuals. Accurate diagnosis is crucial, especially given the significant side effects, including brain hemorrhage, of newer monoclonal antibodies approved for treating earlier stages of Alzheimer's. Although early treatment is more effective, early diagnosis is also more difficult. Several clinical mimickers of AD exist either separately, or in conjunction with AD pathology, adding to the diagnostic complexity. To illustrate the clinical decision-making process, this study includes de-identified cases and reviews of the underlying etiology and pathology of Alzheimer's and available therapies to exemplify diagnostic and treatment subtleties.

Problem

The clinical presentation of Alzheimer's is complex and varied. Multiple other primary brain pathologies present with clinical phenotypes that can be difficult to distinguish from AD. Furthermore, Alzheimer's rarely exists in isolation, as almost all patients also show evidence of other primary brain pathologies, including Lewy body disease and argyrophilic grain disease. The phenotype and progression of AD can vary based on the brain regions affected by pathology, the coexistence and severity of other brain pathologies, the presence and severity of systemic comorbidities such as cardiac disease, the common co-occurrence with psychiatric diagnoses, and genetic risk factors. Additionally, symptoms and progression are influenced by an individual's brain reserve and cognitive reserve, as well as the timing of the diagnosis, which depends on the demographics of both the patient and the diagnosing physician, as well as the availability of biomarkers.

Methods

The optimal clinical and biomarker strategy for accurately diagnosing AD, common neuropathologic co-morbidities and mimickers, and available medication and non-medication-based treatments are discussed. Real-life examples of cognitive loss illustrate the diagnostic and treatment decision-making process as well as illustrative treatment responses.

Implications

AD is best considered a syndromic disorder, influenced by a multitude of patient and environmental characteristics. Additionally, AD existing alone is a unicorn, as there are nearly always coexisting other brain pathologies. Accurate diagnosis with biomarkers is essential. Treatment response is affected by the variables involved, and the effective treatment of Alzheimer's disease, as well as its prevention, requires an individualized, precision medicine strategy.

Antiseizure Medications in Alzheimer's Disease from Preclinical to Clinical Evidence

Alzheimer's disease (AD) and epilepsy are common neurological disorders in the elderly. A bi-directional link between these neurological diseases has been reported, with patients with either condition carrying almost a two-fold risk of contracting the other compared to healthy subjects. AD/epilepsy adversely affects patients' quality of life and represents a severe public health problem. Thus, identifying the relationship between epilepsy and AD represents an ongoing challenge and continuing need. Seizures in AD patients are often unrecognized because they are often nonconvulsive and sometimes mimic some behavioral symptoms of AD. Regarding this, it has been hypothesized that epileptogenesis and neurodegeneration share common underlying mechanisms. Targeted treatment to decrease epileptiform activity could represent a valuable strategy for delaying the neurodegenerative process and related cognitive impairment. Several preclinical studies have shown that some antiseizure medications (ASMs) targeting abnormal network hyperexcitability may change the natural progression of AD. However, to date, no guidelines are available for managing seizures in AD patients because of the paucity of randomized clinical trials sufficient for answering the correlated questions. Future AD clinical studies are mandatory to update clinicians about the symptomatic treatment of seizures in AD patients and recognize whether ASM therapy could change the natural progression of the disease, thereby rescuing cognitive performance.

Aging, NRF2, and TAU: A Perfect Match for Neurodegeneration?

Although the trigger for the neurodegenerative disease process is unknown, the relevance of aging stands out as a major risk for the development of neurodegeneration. In this review, we highlighted the relationship between the different cellular mechanisms that occur as a consequence of aging and transcription factor nuclear factor erythroid-2-related factor 2 (NRF2) and the connection with the TAU protein. We focused on the relevance of NRF2 in the main processes involved in neurodegeneration and associated with aging, such as genomic instability, protein degradation systems (proteasomes/autophagy), cellular senescence, and stem cell exhaustion, as well as inflammation. We also analyzed the effect of aging on TAU protein levels and its aggregation and spread process. Finally, we investigated the interconnection between NRF2 and TAU and the relevance of alterations in the NRF2 signaling pathway in both primary and secondary tauopathies. All these points highlight NRF2 as a possible therapeutic target for tauopathies.

Therapeutic Implications of Probiotics in the Gut Microbe-Modulated Neuroinflammation and Progression of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the accumulation of specific proteins in the brain. A recent study revealed that manipulating gut microbiota (GM) significantly reduced tau pathology and neurodegeneration in an apolipoprotein E isoform-dependent manner. The resilience of a healthy microbiota protects it from a variety of dysbiosis-related pathologies. Convincing evidence has demonstrated the roles of GM in the pathogenesis of AD, which are partly mediated by modified microglial activity in the brain. Therefore, modulation of GM may be a promising therapeutic option for AD prevention. In addition to providing the cells with energy and affecting microglial maturation, these microbial metabolites appear to influence neuronal function. One of the potential therapeutic approaches targeting GM may involve using probiotics. Additionally, human GM and its metabolites have also become potential therapeutic targets for developing interventions for the prevention of disorders. Synbiotics and postbiotics can also be used to treat AD by modulating GM. In addition, physical activity, exercise, and physical fitness are being considered as potential nonpharmacological therapies to reduce signaling pathways related to neuroinflammation. Therefore, interventions targeting GM might be promising strategies for health promotion.

Caffeine for Prevention of Alzheimer's Disease: Is the A2A Adenosine Receptor Its Target?

Alzheimer's disease (AD) is the most prevalent kind of dementia with roughly 135 million cases expected in the world by 2050. Unfortunately, current medications for the treatment of AD can only relieve symptoms but they do not act as disease-modifying agents that can stop the course of AD. Caffeine is one of the most widely used drugs in the world today, and a number of clinical studies suggest that drinking coffee may be good for health, especially in the fight against neurodegenerative conditions such as AD. Experimental works conducted "in vivo" and "in vitro" provide intriguing evidence that caffeine exerts its neuroprotective effects by antagonistically binding to A_2A receptors (A_2ARs), a subset of GPCRs that are triggered by the endogenous nucleoside adenosine. This review provides a summary of the scientific data supporting the critical role that A_2ARs play in memory loss and cognitive decline, as well as the evidence supporting the protective benefits against neurodegeneration that may be attained by caffeine's antagonistic action on these receptors. They are a novel and fascinating target for regulating and enhancing synaptic activity, achieving symptomatic and potentially disease-modifying effects, and protecting against neurodegeneration.