A Comprehensive Review on the Role of the Gut Microbiome in Human Neurological Disorders

Interkingdom signaling between gastrointestinal hormones and the gut microbiome

The interplay between the gut microbiota and gastrointestinal hormones plays a pivotal role in the health of the host and the development of diseases. As a vital component of the intestinal microecosystem, the gut microbiota influences the synthesis and release of many gastrointestinal hormones through mechanisms such as modulating the intestinal environment, producing metabolites, impacting mucosal barriers, generating immune and inflammatory responses, and releasing neurotransmitters. Conversely, gastrointestinal hormones exert feedback regulation on the gut microbiota by modulating the intestinal environment, nutrient absorption and utilization, and the bacterial biological behavior and composition. The distributions of the gut microbiota and gastrointestinal hormones are anatomically intertwined, and close interactions between the gut microbiota and gastrointestinal hormones are crucial for maintaining gastrointestinal homeostasis. Interventions leveraging the interplay between the gut microbiota and gastrointestinal hormones have been employed in the clinical management of metabolic diseases and inflammatory bowel diseases, such as bariatric surgery and fecal microbiota transplantation, offering promising targets for the treatment of dysbiosis-related diseases.

The gut-eye axis: from brain neurodegenerative diseases to age-related macular degeneration

Age-related macular degeneration is a serious neurodegenerative disease of the retina that significantly impacts vision. Unfortunately, the specific pathogenesis remains unclear, and effective early treatment options are consequently lacking. The microbiome is defined as a large ecosystem of microorganisms living within and coexisting with a host. The intestinal microbiome undergoes dynamic changes owing to age, diet, genetics, and other factors. Such dysregulation of the intestinal flora can disrupt the microecological balance, resulting in immunological and metabolic dysfunction in the host, and affecting the development of many diseases. In recent decades, significant evidence has indicated that the intestinal flora also influences systems outside of the digestive tract, including the brain. Indeed, several studies have demonstrated the critical role of the gut-brain axis in the development of brain neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Similarly, the role of the "gut-eye axis" has been confirmed to play a role in the pathogenesis of many ocular disorders. Moreover, age-related macular degeneration and many brain neurodegenerative diseases have been shown to share several risk factors and to exhibit comparable etiologies. As such, the intestinal flora may play an important role in age-related macular degeneration. Given the above context, the present review aims to clarify the gut-brain and gut-eye connections, assess the effect of intestinal flora and metabolites on age-related macular degeneration, and identify potential diagnostic markers and therapeutic strategies. Currently, direct research on the role of intestinal flora in age-related macular degeneration is still relatively limited, while studies focusing solely on intestinal flora are insufficient to fully elucidate its functional role in age-related macular degeneration. Organ-on-a-chip technology has shown promise in clarifying the gut-eye interactions, while integrating analysis of the intestinal flora with research on metabolites through metabolomics and other techniques is crucial for understanding their potential mechanisms.

Causal relationship between gut microbiota, lipids, and neuropsychiatric disorders: A Mendelian randomization mediation study

BACKGROUND

Numerous studies have shown an interconnection between the gut microbiota and the brain via the "gut-brain" axis. However, the causal relationships between gut microbiota, lipids, and neuropsychiatric disorders remain unclear. This study aimed to analyze potential associations among gut microbiota, lipids, and neuropsychiatric disorders-including AD, PD, ALS, MS, SCZ, MDD, and BD-using summary data from large-scale GWAS.

METHODS

Bidirectional Mendelian randomization (MR) with inverse variance weighting (IVW) was the primary method. Supplementary analyses included sensitivity analyses, Steiger tests, and Bayesian weighted MR (BWMR). Mediation analyses used two-step MR (TSMR) and multivariable MR (MVMR).

RESULTS

The analyses revealed 51 positive correlations (risk factors) (β > 0, P < 0.05) and 47 negative correlations (protective factors) (β < 0, P < 0.05) between gut microbiota and neuropsychiatric disorders. In addition, 35 positive correlations (β > 0, P < 0.05) and 22 negative correlations (β < 0, P < 0.05) between lipids and neuropsychiatric disorders were observed. Assessment of reverse causality with the seven neuropsychiatric disorders as exposures and the identified gut microbiota and lipids as outcomes revealed no evidence of reverse causality (P > 0.05). Mediation analysis indicated that the effect of the species Bacteroides plebeius on MDD is partially mediated through the regulation of phosphatidylcholine (16:0_20:4) levels (mediation proportion = 10.9 % [95 % CI = 0.0110-0.2073]).

CONCLUSION

This study provides evidence of a causal relationship between gut microbiota and neuropsychiatric disorders, suggesting lipids as mediators. These findings offer new insights into the mechanisms by which gut microbiota may influence neuropsychiatric disorders.

Gut Microbiota Dysbiosis: Pathogenesis, Diseases, Prevention, and Therapy

Dysbiosis refers to the disruption of the gut microbiota balance and is the pathological basis of various diseases. The main pathogenic mechanisms include impaired intestinal mucosal barrier function, inflammation activation, immune dysregulation, and metabolic abnormalities. These mechanisms involve dysfunctions in the gut-brain axis, gut-liver axis, and others to cause broader effects. Although the association between diseases caused by dysbiosis has been extensively studied, many questions remain regarding the specific pathogenic mechanisms and treatment strategies. This review begins by examining the causes of gut microbiota dysbiosis and summarizes the potential mechanisms of representative diseases caused by microbiota imbalance. It integrates clinical evidence to explore preventive and therapeutic strategies targeting gut microbiota dysregulation, emphasizing the importance of understanding gut microbiota dysbiosis. Finally, we summarized the development of artificial intelligence (AI) in the gut microbiota research and suggested that it will play a critical role in future studies on gut dysbiosis. The research combining multiomics technologies and AI will further uncover the complex mechanisms of gut microbiota dysbiosis. It will drive the development of personalized treatment strategies.

Host-Microbial Cometabolite Ursodeoxycholic Acid Protects Against Poststroke Cognitive Impairment

BACKGROUND

Poststroke cognitive impairment (PSCI) is a common residual disability after stroke, often underestimated and underdiagnosed. We previously found that ursodeoxycholic acid (UDCA), a host-microbiota cometabolite, ameliorates brain damage in stroke mice. Based on these findings, we aimed to evaluate the predictive value of UDCA for PSCI risk in a prospective cohort study.

METHODS AND RESULTS

We recruited 202 patients with mild acute ischemic stroke and 63 patients with symptomatic large-artery atherosclerotic stenosis as the modeling and external validation cohorts, respectively. Mice were subjected to transient middle cerebral artery occlusion, and cognitive function was assessed using the Morris water maze test. Patients with mild acute ischemic stroke who developed PSCI exhibited significant alterations in gut microbiota and plasma bile acid profiles during the acute stroke phase, including a notable reduction in UDCA level. Through feature selection and machine learning, we constructed a predictive model for PSCI incorporating plasma UDCA level, the relative abundance of Clostridia, Bacilli, and Bacteroides, as well as age, educational level, and the presence of moderate to severe white matter lesions. This model exhibited robust predictive performance in both internal (area under the curve, 0.904 [95% CI, 0.808-1.000]) and external (area under the curve, 0.838 [95% CI, 0.742-0.934]) validations. Animal studies in mice also showed reduced UDCA levels in plasma and brain tissue following stroke. UDCA administration improved cognitive function in stroke mice by reducing hippocampal microglial activation and neuronal apoptosis.

CONCLUSIONS

Our findings indicate that UDCA has potential as a biomarker for predicting PSCI risk and plays a neuroprotective role in the progression of PSCI. This suggests that early identification and intervention targeting UDCA could represent a promising strategy for the prevention and treatment of PSCI.

Understanding, inhibiting, and engineering membrane transporters with high-throughput mutational screens

Promiscuous membrane transporters play vital roles across domains of life, mediating the uptake and efflux of structurally and chemically diverse substrates. Although many transporter structures have been solved, the fundamental rules of polyspecific transport remain inscrutable. In recent years, high-throughput genetic screens have solidified as powerful tools for comprehensive, unbiased measurements of variant function and hypothesis generation, but have had infrequent application and limited impact in the transporter field. In this primer, we describe the principles of high-throughput screening methods available for studying polyspecific transporters and comment on the necessity and potential of high-throughput methods for deciphering these transporters in particular. We present several screening approaches which could provide a fundamental understanding of the molecular basis of function and promiscuity in transporters. We further posit how this knowledge can be leveraged to design inhibitors that combat multidrug resistance and engineer transporters as needed tools for synthetic biology and biotechnology applications.

Integrated multi-omics analysis and experimental validation reveals the mechanism of tenuifoliside A activity in Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is characterized by progressive cognitive dysfunction and memory loss. Tenuifoliside A (TFSA) is a constituent of RADIX POLYGALAE, a medicinal herb traditionally used in the clinical treatment of AD in China. However, the therapeutic mechanism of this compound is unknown.

AIM OF THE STUDY

To investigate the effects and pharmacological mechanisms of TFSA in ameliorating AD symptoms in APP/PS1 mice.

MATERIALS AND METHODS

The neuroprotective effects of TFSA were assessed using behavioral tests, transmission electron microscopy, and immunofluorescence staining. The differential metabolites in the feces of model mice were obtained from non-targeted metabolomics analysis. Differential abundances of microbiota in the gut were investigated by 16S rRNA sequencing, and correlations among differential metabolites and microbiota were investigated using an integrated approach.

RESULTS

Cognitive impairment and Aβ burden were mitigated in APP/PS1 mice treated with TFSA. TFSA intervention led to an increase in the diversity of gut microbiota and a reduction in the relative abundance of Firmicutes, Bacteroidetes, and Proteobacteria. There were 71 differential metabolites in mice given high dose of TFSA. In comparison to the AD group, the mice treated with TFSA exhibited a notable enrichment in various pathways including glucose and lipid metabolism, tryptophan metabolism. Based on integrated metabolomics and 16S rRNA sequencing, 23 metabolite-microbiota pairs were different between the TFSA and AD groups, and there was an especially strong correlation between Alistipes and 2,3-dinor-8-epi-prostaglandin F2α. Validation experiment demonstrated TFSA ameliorates AD by regulating metabolism pathways and inhibiting neuroinflammation.

CONCLUSIONS

This study offers a theoretical basis for elucidating the molecular mechanism of TFSA's amelioration of AD. Although the potential pharmacological mechanisms of TFSA are still unknown, we have demonstrated that TFSA inhibits neuroinflammation and improves AD symptoms in APP/PS1 mice by remodeling the microbiota and its metabolites.

Exogenous GABA Alleviates Tourette Syndrome-Like Behavior in Sprague-Dawley Rats by Altering Gut Microbiota and Striatum Metabolism

Context

Tourette syndrome (TS) is a common chronic neuropsychiatric disorder with a prevalence of approximately 1% in children and adolescents. TS is characterized by sudden involuntary motor tics along with vocal tics. A pathological study on postmortem patients has reported a 50-60% reduction in striatal gamma-aminobutyric acidergic (GABAergic) interneurons, suggesting a role for GABAergic system imbalances in tic disorder development. However, the effect of exogenous GABA administration on tic alleviation remains unreported.

Objective

In this study, we aim to investigate the therapeutic effects of exogenous GABA on TS-like behaviors in Sprague-Dawley rats and explore its potential mechanisms, including gut microbiota regulation, oxidative stress mitigation, and restoration of GABA-glutamate balance, to provide insights into TS pathogenesis and alternative treatment strategies.

Materials and Methods

A TS model rat was established through intraperitoneal administration of 3,3-Iminodipropionitrile (150 mg/kg/day), followed by GABA (20 mg/kg/day) administration by gavage. 15 minutes of behavioral testing (stereotypical behavior and head twitching behavior) was then conducted. 16S rRNA sequencing identified microbiome changes, and LC-MS assessed striatal metabolite changes.

Results

The results showed that a 4-week GABA treatment alleviated TS-like behavior in rats. GABA treatment led to an increase in Acinetobacter and other beneficial bacteria. GABA also significantly upregulated 15 striatal metabolites compared with TS group. By correlation analysis of striatal metabolites and intestinal bacteria, statistical analysis showed that Clostridium_sensu_stricto_1 was negatively correlated with metabolites on the top 20 differential gut microbiota and metabolites. Moreover, changes in gut microbiota correlated with alterations in striatal metabolites, suggesting a gut-brain axis involvement.

Conclusion

Exogenous GABA alleviated TS-like behavior in rats by reducing harmful gut flora and modulating striatal GABA-glutamate metabolism. Despite challenges like low blood-brain barrier permeability and dose safety in humans, GABA's therapeutic potential may be realized through prodrug development and optimized dosing. These findings are preliminary and require further clinical validation.

Integrated microbiome and metabolome analysis reveals that Zishen Qingre Lishi Huayu recipe regulates gut microbiota and butyrate metabolism to ameliorate polycystic ovary syndrome

BACKGROUND

s: Polycystic ovary syndrome (PCOS) is a metabolic disorder disease strongly associated with gut microbiota (GM). Zishen Qingre Lishi Huayu recipe (ZQLHR), a traditional Chinese medicinal compound, has patented and shown therapeutic effects in treating PCOS in clinical trials without clear pharmacological mechanisms. This study aimed to disclose the potential therapeutic mechanism of ZQLHR on PCOS.

METHODS

We firstly confirmed the therapeutic effects of ZQLHR treatment in PCOS patients. 16S rRNA sequencing, untargeted metabolomics, fecal microbiota transplantation (FMT), high performance liquid chromatography (HPLC) and Person's correlation analysis were conducted to elucidate the potential therapeutic mechanism.

RESULTS

These results showed that PCOS symptoms in ZQLHR patients were significantly ameliorated. ZQLHR could increase the levels of butyrate-producing Lachnospira and Faecalibacterium and decrease the abundance of Escherichia-Shigella. Untargeted metabolomics showed that ZQLHR significantly improved host metabolic function, particularly butyrate metabolism and citrate cycle (TCA cycle) metabolism. The combined Faecalibacterium and butyrate metabolism datasets were correlated. Stool samples from ZQLHR patients could ameliorate ovarian architecture, significantly reduce testosterone (T), estradiol (E2) and luteinizing hormone (LH) levels and increased follicle-stimulating hormone (FSH) levels and increase the content of butyric acid in PCOS mice (P < 0.01). Moreover, the correlation analysis showed that some biochemical parameters (T, E2, LH levels and FSH) and butyric acid were correlated.

CONCLUSION

We firstly depicted that ZQLHR could alleviate the series of symptom in women with PCOS by regulating gut microbiota and butyrate metabolism. This study provides a scientific basis and new ideas for the therapy of PCOS.

Pathogenesis, diagnosis, and treatment of epilepsy: electromagnetic stimulation-mediated neuromodulation therapy and new technologies

Epilepsy is a severe, relapsing, and multifactorial neurological disorder. Studies regarding the accurate diagnosis, prognosis, and in-depth pathogenesis are crucial for the precise and effective treatment of epilepsy. The pathogenesis of epilepsy is complex and involves alterations in variables such as gene expression, protein expression, ion channel activity, energy metabolites, and gut microbiota composition. Satisfactory results are lacking for conventional treatments for epilepsy. Surgical resection of lesions, drug therapy, and non-drug interventions are mainly used in clinical practice to treat pain associated with epilepsy. Non-pharmacological treatments, such as a ketogenic diet, gene therapy for nerve regeneration, and neural regulation, are currently areas of research focus. This review provides a comprehensive overview of the pathogenesis, diagnostic methods, and treatments of epilepsy. It also elaborates on the theoretical basis, treatment modes, and effects of invasive nerve stimulation in neurotherapy, including percutaneous vagus nerve stimulation, deep brain electrical stimulation, repetitive nerve electrical stimulation, in addition to non-invasive transcranial magnetic stimulation and transcranial direct current stimulation. Numerous studies have shown that electromagnetic stimulation-mediated neuromodulation therapy can markedly improve neurological function and reduce the frequency of epileptic seizures. Additionally, many new technologies for the diagnosis and treatment of epilepsy are being explored. However, current research is mainly focused on analyzing patients' clinical manifestations and exploring relevant diagnostic and treatment methods to study the pathogenesis at a molecular level, which has led to a lack of consensus regarding the mechanisms related to the disease.

Gut microbes: Therapeutic Target for neuropsychiatric disorders

Neuropsychiatric diseases encompass a range of mental and neurological disorders that have a significant and far-reaching effect on an individual's quality of life. These conditions affect not only the mental status but also the physical well-being of individuals, which leads to weakened immune systems and other diseases. Emerging research underscores a significant connection between the gut microbiome and neuropsychiatric diseases, suggesting that microbial communities within the gastrointestinal tract may influence brain function and mental health. Gut dysbiosis is caused by various factors, including stress, diet, inappropriate usage of antibiotics, infections, and so on, all of which can disrupt numerous pathways, resulting in abnormal neurotransmitter signaling, inflammation, and impaired brain function. Similarly, various neuropsychiatric diseases can disrupt the specific microbiome in the gut, leading to gut dysbiosis, often impairing memory and cognitive function. The growing evidence supporting the role of gut dysbiosis in neuropsychiatric disorders has opened up new avenues for therapeutic interventions. Modulating the gut microbiome through strategies such as probiotics, prebiotics, or fecal microbiota transplantation has shown promising results in various studies of neuropsychiatric disorders. However, further research is needed to fully elucidate the mechanisms involved in gut dysbiosis-associated brain changes to develop effective and personalized treatment strategies for neuropsychiatric diseases.

The impact of gut microbiota on the occurrence, treatment, and prognosis of ischemic stroke

Ischemic stroke (IS) is a cerebrovascular disease that predominantly affects middle-aged and elderly populations, exhibiting high mortality and disability rates. At present, the incidence of IS is increasing annually, with a notable trend towards younger affected individuals. Recent discoveries concerning the "gut-brain axis" have established a connection between the gut and the brain. Numerous studies have revealed that intestinal microbes play a crucial role in the onset, progression, and outcomes of IS. They are involved in the entire pathophysiological process of IS through mechanisms such as chronic inflammation, neural regulation, and metabolic processes. Although numerous studies have explored the relationship between IS and intestinal microbiota, comprehensive analyses of specific microbiota is relatively scarce. Therefore, this paper provides an overview of the typical changes in gut microbiota following IS and investigates the role of specific microorganisms in this context. Additionally, it presents a comprehensive analysis of post-stroke microbiological therapy and the relationship between IS and diet. The aim is to identify potential microbial targets for therapeutic intervention, as well as to highlight the benefits of microbiological therapies and the significance of dietary management. Overall, this paper seeks to provide key strategies for the treatment and management of IS, advocating for healthy diets and health programs for individuals. Meanwhile, it may offer a new perspective on the future interdisciplinary development of neurology, microbiology and nutrition.

Research progress on fecal microbiota transplantation in tumor prevention and treatment

The application of fecal microbiota transplantation (FMT) as a therapeutic strategy to directly modify the makeup of the gut microbiota has made significant progress in the last few decades. The gut microbiota, a sizable microbial community present in the human gut, is essential for digestion, immunomodulation, and nutrition absorption. Alternatively, a growing body of research indicates that gut microbiota is a key contributor to cancer, and intratumoral bacteria are considered to be crucial "accomplices" in the development and metastasis of malignancies. The exceptional clinical effectiveness of FMT in treating melanoma patients has been adequately established in earlier research, which has created new avenues for the diagnosis and treatment of cancer and sparked an increasing interest in the treatment and prevention of other cancers. However, further research on the function and mechanisms of the gut microbiota is required to properly comprehend the impact and role of these organisms in tumor regulation. In this article, we present a detailed account of the influence of FMT on the entire course of cancer patients' illness and treatment, from tumor development, metastasis, and invasion, to the impact and application of treatment and prognosis, as well as address the associated mechanisms.

Dynamic changes in the gut microbiota play a critical role in age-associated cognitive dysfunction via SCFAs and LPS synthesis metabolic pathways during brain aging

BACKGROUND

Gut microbiota plays an essential role in cognitive dysfunction during aging. The aim of this study was to investigate the dynamic alterations in the gut microbiota and screen for key gut bacterial taxa correlated with age-associated cognitive dysfunction during natural aging.

METHODS

16S rRNA gene sequencing was performed to determine the composition of the gut microbiota in faecal samples from SAMR1 and SAMP8 mice, cognitively normal controls (NC), and patients with amnestic mild cognitive impairment (aMCI). Faecal microbiota transplantation (FMT) and GMrepo database were used to screen key gut microbiota associated with cognitive decline in aging mice and humans.

RESULTS

The composition of the gut microbiota dynamically changed during natural aging in SAMR1 and SAMP8 mice, as well as in healthy subjects of different ages extracted from the GMrepo database. FMT from SAMR1 to SAMP8 mice altered the gut microbiota composition and improved the cognitive impairment in SAMP8 mice. Key gut bacterial taxa, including Lactobacillus, Akkermansia, Clostridium, Oscillospira and Dorea, were screened and validated to correlate with aging-associated cognitive decline. The function of the key gut bacterial taxa predicted by PICRUSt2 indicated that the metabolic pathways related to short-chain fatty acids (SCFAs) and lipopolysaccharide (LPS) synthesis were involved in age-associated cognitive dysfunction during natural aging.

CONCLUSION

These results demonstrate that the composition of the gut microbiota changes dynamically during brain aging, with some key gut bacterial taxa playing critical roles in age-associated cognitive dysfunction through SCFAs and LPS synthesis metabolic pathways.

A new paradigm for drug discovery in the treatment of complex diseases: drug discovery and optimization

In the past, the drug research and development has predominantly followed a "single target, single disease" model. However, clinical data show that single-target drugs are difficult to interfere with the complete disease network, are prone to develop drug resistance and low safety in clinical use. The proposal of multi-target drug therapy (also known as "cocktail therapy") provides a new approach for drug discovery, which can affect the disease and reduce adverse reactions by regulating multiple targets. Natural products are an important source for multi-target innovative drug development, and more than half of approved small molecule drugs are related to natural products. However, there are many challenges in the development process of natural products, such as active drug screening, target identification and preclinical dosage optimization. Therefore, how to develop multi-target drugs with good drug resistance from natural products has always been a challenge. This article summarizes the applications and shortcomings of related technologies such as natural product bioactivity screening, clarify the mode of action of the drug (direct/indirect target), and preclinical dose optimization. Moreover, in response to the challenges faced by natural products in the development process and the trend of interdisciplinary and multi-technology integration, and a multi-target drug development strategy of "active substances - drug action mode - drug optimization" is proposed to solve the key challenges in the development of natural products from multiple dimensions and levels.

Role of gut microbiota in thalassemia: a review of therapeutic prospects

In recent years, the study of gut microbiota has gradually become a research hotspot in the field of medicine, as gut microbiota dysbiosis is closely related to various diseases. Thalassemia, as a hereditary hemoglobinopathy, has a complex pathophysiological mechanism, and traditional treatment methods show limited efficacy. With a deeper understanding of the gut microbiome, researchers have begun to focus on its role in the pathogenesis of thalassemia and its therapeutic effects. This article aims to review the role of gut microbiota in thalassemia and its potential therapeutic prospects, analyze the latest research findings, and explore the impact and mechanisms of gut microbiota on patients with thalassemia, with the goal of providing new ideas and directions for future research and clinical treatment of thalassemia.

Exploring the effect of soybean fermentation broth (S-FB) on gut microbes of lipopolysaccharide (LPS)-infected loach (Misgurnus anguillicaudatus) using 16S rRNA sequencing

The fermentation products of soybean are rich in beneficial bacteria, which play Shenghui Chu a significant role in maintaining the balance of intestinal microbiota and improving intestinal health. To investigate the immunomodulatory effects of soybean fermentation broth (S-FB) on loach (Misgurnus anguillicaudatus) with lipopolysaccharide (LPS)-induced enteritis, 16S rDNA high-throughput sequencing technology was employed to analyze the composition and structure of intestinal microbiota in two groups: the LPS-treated group (fed with soybean broth) and the control group (normal feeding conditions). The results revealed that the relative abundance of beneficial bacteria, such as Lactobacillus and Muribaculaceae, significantly increased in the treatment group, while the relative abundance of harmful bacteria, including Aeromonas and Shewanella, decreased. These findings suggest that soybean fermentation broth can repair intestinal damage and maintain intestinal health by enhancing the abundance of beneficial bacteria and reducing the pathogenic effects of harmful bacteria on the host. Functional prediction studies of microbial communities also showed that treatment groups primarily affected metabolic and genetic information processing. The research results analyzed the changes in the structure and distribution of intestinal microflora in different groups of loach, providing new insights into the possible role of soybean fermentation liquid in intestinal inflammation.

Ablation of Gut Microbiota Alleviates DON-Induced Neurobehavioral Abnormalities and Brain Damage in Mice

BACKGROUND

Deoxynivalenol (DON) poses a threat to animal and human health, particularly causing damage to the nervous system. Intestinal flora can regulate the nervous system through the gut-brain axis; however, there is currently a lack of evidence on the effect of changing the intestinal flora on the damage to the nervous system caused by DON. Therefore, this study aims to investigate the effect of gut microbiota ablation on neurotoxicity induced by exposure to deoxynivalenol.

METHODS

One hundred-twenty (120) specific pathogen-free (SPF) male C57BL/6j mice were randomly divided into four groups (control group, microbiota-uncleaned group + 5 mg/kg/BW DON, microbiota-cleared group, and microbiota-cleared group + 5 mg/kg/BW DON). The open field and Morris behavior tests were used to evaluate behavior changes after DON exposure. After 14 days of treatment, the mice were euthanized and brain tissues were collected for further analysis.

RESULTS

The tests showed that DON exposure led to anxiety and decreased learning ability in mice with no gut microbiota ablation. We also observed pathological changes including neuronal shrinkage, degeneration, and cortical edema in the mice with no microbiota ablation after DON exposure. In addition, the protein and mRNA levels of tight junction proteins and anti-inflammatory factors were decreased in the mice with no microbiota ablation after DON exposure compared with mice with ablated microbiota.

CONCLUSIONS

We concluded that the presence of microbiota plays a key role in the neurotoxicity induced by DON; thus, ablation of the intestinal microbiota can effectively improve brain damage caused by DON.

Research Status and Trends of Gut Microbiota and Intestinal Diseases Based on Bibliometrics

Gut microbiota plays an important role in gut health, and its dysbiosis is closely related to the pathogenesis of various intestinal diseases. The field of gut microbiota and intestinal diseases has not yet been systematically quantified through bibliometric methods. This study conducted bibliometric analysis to delineate the evolution of research on gut microbiota and intestinal diseases. Data were sourced from the Web of Science Core Collection database from 2009 to 2023 and were scientometrically analyzed using CiteSpace. We have found that the number of annual publications has been steadily increasing and showing an upward trend. China and the Chinese Academy of Sciences are the country and institution with the most contributions, respectively. Frontiers in Microbiology and Nutrients are the journals with the most publications, while Plos One and Nature are the journals with the most citations. The field has shifted from focusing on traditional descriptive analysis of gut microbiota composition to exploring the causal relationship between gut microbiota and intestinal diseases. The research hotspots and trends mainly include the correlation between specific intestinal diseases and gut microbiota diversity, the mechanism of gut microbiota involvement in intestinal diseases, the exploration of important gut microbiota related to intestinal diseases, and the relationship between gut microbiota and human gut health. This study provides a comprehensive knowledge map of gut microbiota and intestinal diseases, highlights key research areas, and outlines potential future directions.

Gut-Brain Axis-Based Polygala Tenuifolia and Magnolia Officinalis Improve D-gal-Induced Cognitive Impairment in Mice Through cAMP and NF-κB Signaling Pathways

Purpose

Polygala tenuifolia Willd. (PT) is commonly used to address cognitive impairment (CI), while Magnolia officinalis Rehd. et Wils (MO) is often prescribed for gastrointestinal issues as well as CI. This study seeks to explore the impacts and mechanisms behind the combined therapy of PT and MO (PM) in treating CI, based on the concept of the gut-brain axis.

Methods

The characteristic components of PT, MO, and PM were identified using ultra-high performance liquid chromatography-tandem triple quadrupole mass Spectrometry (UPLC-MS/MS). A mouse model was established by D-gal induction, and the effects of PT, MO, and PM on CI were evaluated through behavioral tests, pathological staining, and Enzyme-Linked Immunosorbent Assay (ELISA). Subsequently, network pharmacology was used to analyze the potential mechanisms by which PM improves CI, followed by validation through Western blotting (WB), traditional Chinese medicine (TEM), Immunofluorescence (IF), and 16S rRNA.

Results

PT, MO, and PM can each alleviate cognitive decline and neuropathological damage in D-gal mice to varying degrees, reduce the expression of pro-inflammatory factors (TNF-α, IL-1β, IL-6, IFN-γ, LPS) in serum or hippocampal tissue, and increase SOD and GSH levels. Network pharmacology analysis and molecular experiments confirmed that PM upregulates the expression of tight junction s (TJs), enhances the expression of proteins in the cAMP pathway, and inhibits p-NF-κB-p65 expression. PM reverses D-gal-induced gut microbiota dysbiosis, increases the abundance of SCFA-producing bacteria, and decreases the abundance of LPS-producing bacteria.

Conclusion

PM alleviates CI by reducing inflammation and oxidative stress, protecting the blood-brain barrier (BBB) and intestinal barrier, inhibiting the NF-κB pathway, activating the cAMP pathway, and regulating gut microbiota.

Investigating Causal Links Between Gut Microbiota and Neurological Disorders via Genome-Wide Association Studies

Many reports have highlighted the involvement of the gut microbiome in the occurrence, progression, and outcomes of neurological disorders. However, current reports are somewhat chaotic, especially concerning whether the gut microbiota has a causal effect on various neurological diseases. Furthermore, whether there is a common mechanism involving gut microbial communities in these neurological disorders has not to be revealed. In this study, we leveraged data from the largest-scale genome-wide association study (GWAS) by the MiBioGen consortium, which includes genetic and microbial composition data from 18,340 individuals spanning 24 cohorts. We utilized single-nucleotide polymorphisms (SNPs) associated with the gut microbiome as instrumental variables (IVs) in Mendelian randomization (MR) analyses. These IVs were rigorously selected based on their genome-wide and locus-wide significance to ensure robust causal inference. Our study established robust associations between specific gut microbiota and various neurological disorders using MR. We systematically depicted the bacteria with causal relationships in all diseases, covering the levels of phylum, class, order, family, and genus. We identified 34 bacterial species as significant risk or protective factors across disorders, including two main phylum levels such as Firmicutes (22 species) and Proteobacteria (8 species), as well as Bacteroidetes (2 species), Actinobacteria (1 species), and Verrucomicrobiota (1 species). At the family level of bacteria, we found that Lachnospiraceae and Ruminococcaceae are the most related to these 11 diseases and they may play different roles in the same disease.

Bibliometric analysis of the intestinal microbiota and demyelinating diseases, particularly multiple sclerosis, since 2014

Background

The gut-brain axis (GBA) represents a complex, bidirectional communication network that connects the central nervous system (CNS) and the gastrointestinal system. Our study aimed to explore the correlation between the intestinal microbiota and demyelinating diseases from a bibliometric perspective, focusing on research since 2014.

Methods

A comprehensive search was carried out on the Web of Science Core Collection (WoSCC) to locate studies on the intestinal microbiota and demyelinating diseases, with a focus on publications from 1 January 2014 to 29 March 2024. We visualized and analyzed the data using VOSviewer, CiteSpace, and Charticulator.

Results

We gathered 429 scholarly articles on the intestinal microbiota and demyelinating disorders published in the past 10 years. Research concerning the intestinal microbiota and demyelinating diseases has demonstrated a consistent increase in frequency over time. The USA has the highest number of publications, while Canada has the highest average number of citations, reaching as high as 3,429, which is greater than that of the USA. Moreover, the journal with the highest number of publications was Frontiers in Immunology, with 33 publications and 1,494 citations. The majority of the scholars focused on "multiple sclerosis" and "gut microbiota," which are the primary keywords in the field of the intestinal microbiota and demyelinating diseases.

Conclusion

This study conducted a comprehensive analysis of existing research investigating the correlation between the intestinal microbiota and demyelinating diseases. Using advanced bibliometric tools such as VOSviewer and CiteSpace, this study analyzed the intricate relationship between the intestinal microbiota and the pathogenesis of demyelinating conditions. In addition, the study used literature statistical analysis to identify research hotspots and future directions in the field.

Advancements in the investigation of gut microbiota-based strategies for stroke prevention and treatment

Stroke represents a predominant cause of mortality and disability on a global scale, impacting millions annually and exerting a considerable strain on healthcare systems. The incidence of stroke exhibits regional variability, with ischemic stroke accounting for the majority of occurrences. Post-stroke complications, such as cognitive impairment, motor dysfunction, and recurrent stroke, profoundly affect patients' quality of life. Recent advancements have elucidated the microbiota-gut-brain axis (MGBA), underscoring the complex interplay between gut health and brain function. Dysbiosis, characterized by an imbalance in gut microbiota, is significantly linked to an elevated risk of stroke and unfavorable outcomes. The MGBA plays a crucial role in modulating immune function, neurotransmitter levels, and metabolic byproducts, which may intensify neuroinflammation and impair cerebral health. This review elucidates the role of MGBA in stroke pathophysiology and explores potential gut-targeted therapeutic strategies to reduce stroke risk and promote recovery, including probiotics, prebiotics, pharmacological interventions, and dietary modifications. However, the current prevention and treatment strategies based on intestinal flora still face many problems, such as the large difference of individual intestinal flora, the stability of efficacy, and the long-term safety need to be considered. Further research needs to be strengthened to promote its better application in clinical practice.

Impaired intestinal permeability in patients with multiple sclerosis

BACKGROUND

A number of recent studies have shown that the intestinal microbiome, part of the brain-gut axis, is implicated in the pathophysiology of multiple sclerosis. An essential part of this axis, is the intestinal barrier and gastrointestinal disorders with intestinal barrier dysregulation appear to be linked to CNS demyelination, and hence involved in the etiopathogenesis of multiple sclerosis (MS).

OBJECTIVE

The aim of this study was to evaluate the integrity of the intestinal barrier in patients with clinically definite multiple sclerosis (CDMS) and clinically isolated syndrome (CIS) using two serum biomarkers, claudin-3 (CLDN3), a component of tight epithelial junctions, and intestinal fatty acid binding protein (I-FABP), a cytosolic protein in enterocytes.

METHODS

Serum levels of CLDN3 in 37 MS patients and 22 controls, and serum levels of I-FABP in 46 MS patients and 51 controls were measured using commercial ELISA kits. Complete laboratory tests excluded the presence of gluten-related disorders in all subjects. Thirty MS patients received either disease-modifying drugs (DMD), immunosuppression (IS) or corticosteroid treatment.

RESULTS

CLDN3 levels were only significantly higher in the MS patients treated with DMD or IS compared to the control group (P=0.006). There were no differences in I-FABP serum levels between the groups. Serum CLDN3 levels did not correlate with serum I-FABP levels in CDMS, in CIS patients or controls.

CONCLUSIONS

In multiple sclerosis patients, the intestinal epithelium may be impaired with increased permeability, but without significant enterocyte damage characterized by intracellular protein leakage. Based on our data, CLDN3 serum levels appear to assess intestinal dysfunction in MS patients but mainly in treated ones.

Lactobacillaceae and Parkinson's disease: An apparent paradox

Parkinson's disease (PD) is a neurodegenerative disorder predominantly known for its motor symptoms such as bradykinesia, rigidity and tremor, but the disorder is also increasingly recognized for its association with impaired gastrointestinal function. The composition of the gut microbiome is known to be different in PD compared with healthy individuals. One of the bacterial families with increased abundance in people with PD is Lactobacillaceae. Interestingly, opposite effects have been ascribed to Lactobacillaceae in PD. A number of studies have linked Lactobacillaceae spp. in the gut to worse motor function, and to premature degradation of levodopa. However, other studies have linked administration of Lactobacillaceae-containing probiotics to improved motor function and reduced gastrointestinal problems. In this narrative review, we investigate this apparent paradox. The key to its understanding appears to lie in the specific species of Lactobacillaceae. The species L. plantarum in particular seemed to show a correlation with improved motor symptoms, as well as a reduction in intestinal inflammation, whereas L. brevis, L. curvatus and L. fermentum have properties that might be detrimental to people with PD.

Gut microbiota in multiple sclerosis and animal models

Multiple sclerosis (MS) is a chronic central nervous system (CNS) neurodegenerative and neuroinflammatory disease marked by a host immune reaction that targets and destroys the neuronal myelin sheath. MS and correlating animal disease models show comorbidities, including intestinal barrier disruption and alterations of the commensal microbiome. It is accepted that diet plays a crucial role in shaping the microbiota composition and overall gastrointestinal (GI) tract health, suggesting an interplay between nutrition and neuroinflammation via the gut-brain axis. Unfortunately, poor host health and diet lead to microbiota modifications that could lead to significant responses in the host, including inflammation and neurobehavioral changes. Beneficial microbial metabolites are essential for host homeostasis and inflammation control. This review will highlight the importance of the gut microbiota in the context of host inflammatory responses in MS and MS animal models. Additionally, microbial community restoration and how it affects MS and GI barrier integrity will be discussed.

Gut Microbiota Mediates Neuroinflammation in Alzheimer's Disease: Unraveling Key Factors and Mechanistic Insights

The gut microbiota, the complex community of microorganisms that inhabit the gastrointestinal tract, has emerged as a key player in the pathogenesis of neurodegenerative disorders, including Alzheimer's disease (AD). AD is characterized by progressive cognitive decline and neuronal loss, associated with the accumulation of amyloid-β plaques, neurofibrillary tangles, and neuroinflammation in the brain. Increasing evidence suggests that alterations in the composition and function of the gut microbiota, known as dysbiosis, may contribute to the development and progression of AD by modulating neuroinflammation, a chronic and maladaptive immune response in the central nervous system. This review aims to comprehensively analyze the current role of the gut microbiota in regulating neuroinflammation and glial cell function in AD. Its objective is to deepen our understanding of the pathogenesis of AD and to discuss the potential advantages and challenges of using gut microbiota modulation as a novel approach for the diagnosis, treatment, and prevention of AD.

Akkermansia muciniphila: biology, microbial ecology, host interactions and therapeutic potential

Akkermansia muciniphila is a gut bacterium that colonizes the gut mucosa, has a role in maintaining gut health and shows promise for potential therapeutic applications. The discovery of A. muciniphila as an important member of our gut microbiome, occupying an extraordinary niche in the human gut, has led to new hypotheses on gut health, beneficial microorganisms and host-microbiota interactions. This microorganism has established a unique position in human microbiome research, similar to its role in the gut ecosystem. Its unique traits in using mucin sugars and mechanisms of action that can modify host health have made A. muciniphila a subject of enormous attention from multiple research fields. A. muciniphila is becoming a model organism studied for its ability to modulate human health and gut microbiome structure, leading to commercial products, a genetic model and possible probiotic formulations. This Review provides an overview of A. muciniphila and Akkermansia genus phylogeny, ecophysiology and diversity. Furthermore, the Review discusses perspectives on ecology, strategies for harnessing beneficial effects of A. muciniphila for human mucosal metabolic and gut health, and its potential as a biomarker for diagnostics and prognostics.

Effects of Different Cow-Milk Beta-Caseins on the Gut-Brain Axis: A Narrative Review of Preclinical, Animal, and Human Studies

The gut and brain communicate through bidirectional neural, endocrine, and immune signals to coordinate central nervous system activity with gastrointestinal function. Dysregulated inflammation can promote immune cell activation and increase entero-endocrine signaling and intestinal permeability; hence, a functional gut-brain axis is necessary for a healthy digestive system. The consumption of milk products can lead to gut discomfort via effects on gastrointestinal tract function and the inflammatory state, which, in turn, affect the brain. A1 β-casein and A2 β-casein are major components of bovine-milk protein, and their digestion may result in different physiological effects following the consumption of milk products. Peptides derived from A1 β-casein, such as β-casomorphins, may increase gut dysfunction and inflammation, thereby modulating the availability of bioactive metabolites in the bloodstream and contribute to changes in cognitive function. This narrative review examines the functional interrelationships between the consumption of cow-milk-derived β-caseins and their effect on the brain, immune system, and the gut, which together comprise the gut-brain axis.

Crosstalk between gut microbiotas and fatty acid metabolism in colorectal cancer

Colorectal cancer (CRC) is the third most common malignancy globally and the second leading cause of cancer-related mortality. Its development is a multifactorial and multistage process influenced by a dynamic interplay between gut microbiota, environmental factors, and fatty acid metabolism. Dysbiosis of intestinal microbiota and abnormalities in microbiota-associated metabolites have been implicated in colorectal carcinogenesis, highlighting the pivotal role of microbial and metabolic interactions. Fatty acid metabolism serves as a critical nexus linking dietary patterns with gut microbial activity, significantly impacting intestinal health. In CRC patients, reduced levels of short-chain fatty acids (SCFAs) and SCFA-producing bacteria have been consistently observed. Supplementation with SCFA-producing probiotics has demonstrated tumor-suppressive effects, while therapeutic strategies aimed at modulating SCFA levels have shown potential in enhancing the efficacy of radiation therapy and immunotherapy in both preclinical and clinical settings. This review explores the intricate relationship between gut microbiota, fatty acid metabolism, and CRC, offering insights into the underlying mechanisms and their potential translational applications. Understanding this interplay could pave the way for novel diagnostic, therapeutic, and preventive strategies in the management of CRC.

Investigating casual association among gut microbiome and esophageal cancer: A Mendelian randomization study

The gut microbiota has been strongly linked to gastrointestinal cancer, but the relationship between gut microbiota and esophageal cancer (EC) is still not fully understood. We conducted a 2-sample Mendelian randomization (MR) study to unveil the potential impact of intestinal microorganisms on EC in East Asian populations. In order to delve deeper into the potential causal relationship between gut microbiota and EC, we conducted a 2-sample MR analysis, utilizing 211 single nucleotide polymorphisms associated with gut microbiota, sourced from the largest genome-wide association study on gut microbiota, for our analysis. To estimate the causal relationship, we employed the inverse variance weighting method. In addition, to assess the potential influence of pleiotropy, we used MR-Egger regression in our analysis. Among the 10 specific bacterial taxa identified using the inverse variance weighting as being associated with the risk of EC, we observed a positive association between family Bacteroidaceae (P = .04), genus Bacteroides (P = .04), genus Bilophila (P = .02), genus Candidatus Soleaferrea (P = .02) and the EC, while family Victivallaceae (P = .03), genus Eubacterium coprostanoligenes (P = .01), genus Catenibacterium (P = .01), genus Coprococcus2 (P = .01), unknowngenus.id.959 (P = .02) and unknowngenus.id.1868 (P = .01) may be associated with a reduced risk of EC. Our MR analysis indicate a probable association between gut microbiota and the development and advancement of EC. These findings offer novel perspectives on the possible application of targeted gut bacteria for the prevention and management of EC.

Gut microbiota: A new window for the prevention and treatment of neuropsychiatric disease

Under normal physiological conditions, gut microbiota and host mutually coexist. They play key roles in maintaining intestinal barrier integrity, absorption, and metabolism, as well as promoting the development of the central nervous system (CNS) and emotional regulation. The dysregulation of gut microbiota homeostasis has attracted significant research interest, specifically in its impact on neurological and psychiatric disorders. Recent studies have highlighted the important role of the gut- brain axis in conditions including Alzheimer's Disease (AD), Parkinson's Disease (PD), and depression. This review aims to elucidate the regulatory mechanisms by which gut microbiota affect the progression of CNS disorders via the gut-brain axis. Additionally, we discuss the current research landscape, identify gaps, and propose future directions for microbial interventions against these diseases. Finally, we provide a theoretical reference for clinical treatment strategies and drug development for AD, PD, and depression.

Unravelling the neuroimmune nexus: insights into epilepsy pathology and the role of S100b protein in brain-gut axis modulation: a literature review

Epilepsy, a chronic neurological condition marked by recurrent, unprovoked seizures, involves complex pathophysiological mechanisms. Recent advancements have expanded our understanding from traditional neuronal dysfunction to include neuroimmune interactions and the influence of the brain-gut-bio-axis. This review explores the role of the S100b protein within these contexts, noted for its involvement in neuroinflammatory processes and as a potential biomarker. Furthermore, it discusses the emerging significance of the gut microbiome in modulating neuroimmune responses and seizure activity. The review integrates findings from recent studies, emphasizing the critical role of the S100b signalling pathway and the gut-brain axis in epilepsy pathology. The interplay between neuroimmune mechanisms and gut microbiota offers novel insights and potential therapeutic targets, underlining the need for further research to exploit these connections for clinical benefit.

Saikosaponin A alleviates depressive-like behavior induced by reserpine in mice by regulating gut microflora and inflammatory responses

Saikosaponin A (SSA), a key ingredient of Chaihu-Shugan-San, has been shown to possess anti-inflammatory, antioxidant and antidepressant properties. Therefore, the present study aimed to investigate the potential mechanism of action and the effect of SSA on reserpine-induced depressive-like symptoms in mice. Establishing mouse model of depression using intraperitoneal injection of reserpine (RSP). Forced swimming test, tail suspension test and sucrose preference test were used to assess depression-like behavior in mice. The results showed that mice exposed to RSP not only showed weight loss and depressive behavior, but also elevated levels of IL-1β and TNF-α, as well as upregulated levels of reactive oxygen species (ROS) and lipid peroxides in the hippocampus. Detection of changes in the intestinal flora of mice using 16S rRNA, it was observed that the intestinal flora changed following SSA treatment. Not only was there an increase in the overall abundance of the intestinal microbiota, but there was also a significant down-regulation of the Firmicutes and an up-regulation of the Verrucomicrobia at the phylum level. Furthermore, SSA treatment markedly improved depressive-like behavior induced by RSP, alleviated damage to the hippocampus, elevated levels of monoamine neurotransmitters, suppressed inflammatory factors in the hippocampus, reduced hippocampal oxidative stress, and restored gut microbiota disruption in RSP-induced mice. The findings propose that SSA has the potential to alleviate depressive symptoms in mice by enhancing monoamine neurotransmitter levels, suppressing hippocampal inflammation, and modifying gut microbial composition.

Microbiome Integrity Enhances the Efficacy and Safety of Anticancer Drug

The intricate relationship between anticancer drugs and the gut microbiome influences cancer treatment outcomes. This review paper focuses on the role of microbiome integrity in enhancing the efficacy and safety of anticancer drug therapy, emphasizing the pharmacokinetic interactions between anticancer drugs and the gut microbiota. It explores how disruptions to microbiome composition, or dysbiosis, can alter drug metabolism, immune responses, and treatment side effects. By examining the mechanisms of microbiome disruption caused by anticancer drugs, this paper highlights specific case studies of drugs like cyclophosphamide, 5-fluorouracil, and irinotecan, and their impact on microbial diversity and clinical outcomes. The review also discusses microbiome-targeted strategies, including prebiotics, probiotics, postbiotics, and fecal microbiota transplantation (FMT), as promising interventions to enhance cancer treatment. Furthermore, the potential of microbiome profiling in personalizing therapy and integrating these interventions into clinical practice is explored. Finally, this paper proposes future research directions, including developing novel biomarkers and a deeper comprehension of drug-microbiome interactions, to respond to current gaps in knowledge and improve patient outcomes in cancer care.

The Inflammatory Mechanism of Parkinson's Disease: Gut Microbiota Metabolites Affect the Development of the Disease Through the Gut-Brain Axis

Parkinson's disease is recognized as the second most prevalent neurodegenerative disorder globally, with its incidence rate projected to increase alongside ongoing population growth. However, the precise etiology of Parkinson's disease remains elusive. This article explores the inflammatory mechanisms linking gut microbiota to Parkinson's disease, emphasizing alterations in gut microbiota and their metabolites that influence the disease's progression through the bidirectional transmission of inflammatory signals along the gut-brain axis. Building on this mechanistic framework, this article further discusses research methodologies and treatment strategies focused on gut microbiota metabolites, including metabolomics detection techniques, animal model investigations, and therapeutic approaches such as dietary interventions, probiotic treatments, and fecal transplantation. Ultimately, this article aims to elucidate the relationship between gut microbiota metabolites and the inflammatory mechanisms underlying Parkinson's disease, thereby paving the way for novel avenues in the research and treatment of this condition.

Hypothalamus-pituitary-adrenal and gut-brain axes in biological interaction pathway of the depression

The hypothalamus-pituitary-adrenal (HPA) and gut-brain axes are vital biological pathways in depression. The HPA axis regulates the body's stress response, and chronic stress can lead to overactivation of the HPA axis, resulting in elevated cortisol levels that contribute to neuronal damage, particularly in regions such as the hippocampus and prefrontal cortex, both of which are involved in mood regulation and mental disorders. In parallel, the gut-brain axis, a bidirectional communication network between the gut microbiota and the central nervous system, influences emotional and cognitive functions. Imbalances in gut microbiota can affect the HPA axis, promoting inflammation and increasing gut permeability. This allows endotoxins to enter the bloodstream, contributing to neuroinflammation and altering neurotransmitter production, including serotonin. Since the majority of serotonin is produced in the gut, disruptions in this pathway may be linked to depressive symptoms. This review explores the interplay between the HPA axis and the gut-brain axis in the context of depression.

Benign regulation of short-chain fatty acids: the underlying mechanism of the beneficial effects of manual acupuncture on cognitive ability and the intestinal mucosal barrier in APP/PS1 mice

Background

Gut microbiota dysbiosis is closely related to the occurrence and progression of Alzheimer's disease (AD). The destruction of the intestinal mucosal barrier caused by a decrease in short-chain fatty acids (SCFAs) plays a key role in gut microbiota dysbiosis-induced neuroinflammation in AD. Our previous research confirmed for the first time that manual acupuncture (MA) can benignly modulate gut microbiota dysbiosis, alleviating the destruction of the intestinal mucosal barrier. However, the regulatory effect of MA on SCFAs remains elusive, and the underlying mechanism by which MA improves intestinal mucosal barrier function requires elucidation.

Methods

In the APP/PS1 manual acupuncture (Am) group, MA was applied at Baihui (GV20), Yintang (GV29), and Zusanli (ST36). Probiotics were delivered to the APP/PS1 probiotic (Ap) group. Alterations in spatial learning and memory, intestinal barrier function, SCFAs in feces and serum, the expression of FFAR3 and NF-κB, and inflammatory cytokines were evaluated in each group.

Results

Compared with those in the C57BL/6 control (Cc) group, cognitive ability was significantly decreased, SCFAs and FFAR3 expression were obviously decreased, intestinal barrier integrity was drastically impaired, and the expression of NF-κB and the levels of intestinal IL-1β and TNF-α were increased in the APP/PS1 control (Ac) group. These changes were reversed by MA and probiotics.

Conclusion

MA can significantly reduce intestinal inflammation and alleviate destruction of the intestinal mucosal barrier in APP/PS1 mice. SCFAs/FFAR3/NF-κB may be important targets through which MA benignly regulates intestinal mucosal barrier function.

The possible effects of chili peppers on ADHD in relation to the gut microbiota

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, which is characterized by inattention, impulsivity and hyperactivity. Although the etiology and pathogenesis of ADHD are not fully understood, existing studies have shown that it may be related to genetic factors, environmental factors, abnormal brain development, and psychosocial factors. In recent years, with the concept of microbioa-gut-brain axis (MGBA), more and more studies have begun to pay attention to the effect of gut microbiota on ADHD. Dietary structure can significantly change the diversity and abundance of gut microbiota. Therefore, dietary supplements or food additives to regulate gut microbiota have become one of the potential ways to treat ADHD. Peppers, as an important dietary component, have potential value in regulating gut microbiota. Among them, capsaicin (8-methyl N-vanillyl-6-noneamide, CAP), as a key active component of peppers, has been shown to have potential therapeutic effects on central nervous system (CNS) diseases such as Parkinson's disease, epilepsy, and depression. In addition, much attention has been paid to the beneficial effects of CAP on gut microbiota. Chili peppers contain not only CAP, but also rich in vitamin C and fatty acids, all of which may ameliorate ADHD by modulating the gut microbiota. This finding not only provides a potential treatment for ADHD, but also provides a new perspective to expand the research and clinical treatment of ADHD pathogenesis. Although current research on the potential therapeutic effects of chili peppers on ADHD is still at an early stage and requires further verification through larger-scale and more rigorous controlled studies, its potential clinical value cannot be ignored.

Novel Microbial Engraftment Trajectories Following Microbiota Transplant Therapy in Ulcerative Colitis

BACKGROUND AND AIMS

Microbiota transplant therapy (MTT) is an emerging treatment for ulcerative colitis (UC). One proposed mechanism for the benefit of MTT is through engraftment of donor microbiota; however, engraftment kinetics are unknown. We identified SourceTracker as an efficient method both to determine engraftment and for the kinetic study of engrafting donor taxa to aid in determining the mechanism of how this therapy may treat UC.

METHODS

Ulcerative colitis patients received either encapsulated (drug name MTP-101C) or placebo capsules daily for 8 weeks followed by a 4-week washout period. Amplicon sequence data from donors and patients were analyzed using the Bayesian algorithm SourceTracker.

RESULTS

Twenty-seven patients were enrolled, 14 to placebo and 13 to MTT. Baseline Shannon and Chao1 indices negatively correlated with week 12 donor engraftment for patients treated with active drug capsules but not for placebo patients. SourceTracker engraftment positively correlated with the week 12 distance from donors measured using the Bray-Curtis similarity metric in treated patients but not with placebo. Engraftment at week 12 was significantly higher in the MTT group than in the placebo group. We identified engrafting taxa from donors in our patients and quantified the proportion of donor similarity or engraftment during weeks 1 through 8 (active treatment) and week 12, 4 weeks after the last dose.

CONCLUSION

SourceTracker can be used as a simple and reliable method to quantify donor microbial community engraftment and donor taxa contribution in patients with UC and other inflammatory conditions treated with MTT.

Exploring the associations of gut microbiota with inflammatory and the early hematoma expansion in intracerebral hemorrhage: from change to potential therapeutic objectives

Background

Although a great deal of research has explored the possibility of a systemic inflammatory response and dysbiosis of the gut microbiota after an intracerebral hemorrhage (ICH), the relationships between gut microbiota and blood inflammatory indicators as well as their role in the hematoma expansion following an early-stage mild-to-moderate ICH (emICH) remain unknown. This study analyzes these changes and associations in order to predict and prevent hematoma expansion after emICH.

Methods

The study included 100 participants, with 70 individuals diagnosed with emICH (30 with hematoma expansion and 40 without hematoma expansion, referred to as the HE and NE groups) and 30 healthy controls matched in terms of age and gender (HC). We used 16S rRNA gene sequencing to explore the gut microbial structure and its underlying associations with blood inflammatory parameters in the HE group.

Results

Our findings showed a significant decrease in the diversity and even distribution of microorganisms in the HE group when compared to the HC and NE groups. The composition of the gut microbiota experienced notable alterations in the emICH group, especially in HE. These changes included a rise in the number of gram-negative pro-inflammatory bacteria and a decline in the level of probiotics. Furthermore, we observed strong positive connections between bacteria enriched in the HE group and levels of systemic inflammation. Several microbial biomarkers (e.g. Escherichia_Shigella, Enterobacter, and Porphyromonas) were revealed in disparateiating HE from HC and NE. Analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) exposed disturbances in essential physiological pathways, especially those related to inflammation (such as the Toll-like receptor signaling pathway), in the HE group.

Conclusions

Our exploration indicated that individuals with emICH, especially those with HE, demonstrate notably different host-microbe interactions when compared to healthy individuals. We deduced that emICH could rapidly trigger the dysbiosis of intestinal flora, and the disturbed microbiota could, in turn, exacerbate inflammatory response and increase the risk of hematoma expansion. Our comprehensive research revealed the potential of intestinal flora as a potent diagnostic tool, emphasizing its significance as a preventive target for HE.

Glial polarization in neurological diseases: Molecular mechanisms and therapeutic opportunities

Glial cell polarization plays a pivotal role in various neurological disorders. In response to distinct stimuli, glial cells undergo polarization to either mitigate neurotoxicity or facilitate neural repair following injury, underscoring the importance of glial phenotypic polarization in modulating central nervous system function. This review presents an overview of glial cell polarization, focusing on astrocytes and microglia. It explores the involvement of glial polarization in neurological diseases such as Alzheimer's disease, Parkinson's disease, stroke, epilepsy, traumatic brain injury, amyotrophic lateral sclerosis, multiple sclerosis and meningoencephalitis. Specifically, it emphasizes the role of glial cell polarization in disease pathogenesis through mechanisms including neuroinflammation, neurodegeneration, calcium signaling dysregulation, synaptic dysfunction and immune response. Additionally, it summarizes various therapeutic strategies including pharmacological treatments, dietary supplements and cell-based therapies, aimed at modulating glial cell polarization to ameliorate brain dysfunction. Future research focused on the spatio-temporal manipulation of glial polarization holds promise for advancing precision diagnosis and treatment of neurological diseases.

Gut microbiota as a potential therapeutic target for children with cerebral palsy and epilepsy

Gut microbiota (GM), the "second genome," exerts influence on human health by impacting brain function through the gut-brain axis. This interaction involves various mechanisms, including immune regulation, metabolites, and neuronal pathways. The application of the next-generation sequencing technology provides a revolutionary tool for the study of GM, which contributes to a deeper comprehension of the GM-host relationship. Children with cerebral palsy (CP), a common neurological disorder in children, are more likely to develop epilepsy, which can exacerbate CP symptoms, particularly those related to cognitive impairment and gastrointestinal tract, such as constipation. The current study identified specific changes in the GM of children with CP accompanied by epilepsy. Furthermore, both diet and oral microbiota have the potential to influence the composition of the GM. Interventions with probiotics and dietary fiber based on GM can improve constipation and cognition, and this approach may be a potential therapeutic strategy.

A review on gut microbiota and miRNA crosstalk: implications for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and progressive neuronal damage. Recent research has highlighted the significant roles of the gut microbiota and microRNAs (miRNAs) in the pathogenesis of AD. This review explores the intricate interaction between gut microbiota and miRNAs, emphasizing their combined impact on Alzheimer's progression. First, we discuss the bidirectional communication within the gut-brain axis and how gut dysbiosis contributes to neuroinflammation and neurodegeneration in AD. Changes in gut microbiota composition in Alzheimer's patients have been linked to inflammation, which exacerbates disease progression. Next, we delve into the biology of miRNAs, focusing on their roles in gene regulation, neurodevelopment, and neurodegeneration. Dysregulated miRNAs are implicated in AD pathogenesis, influencing key processes like inflammation, tau pathology, and amyloid deposition. We then examine how the gut microbiota modulates miRNA expression, particularly in the brain, potentially altering neuroinflammatory responses and synaptic plasticity. The interplay between gut microbiota and miRNAs also affects blood-brain barrier integrity, further contributing to Alzheimer's pathology. Lastly, we explore therapeutic strategies targeting this gut microbiota-miRNA axis, including probiotics, prebiotics, and dietary interventions, aiming to modulate miRNA expression and improve AD outcomes. While promising, challenges remain in fully elucidating these interactions and translating them into effective therapies. This review highlights the importance of understanding the gut microbiota-miRNA relationship in AD, offering potential pathways for novel therapeutic approaches aimed at mitigating the disease's progression.

Unusual Phospholipids from Morganella morganii Linked to Depression

A multifactorial association study detected a probable causal connection between the prevalence of Morganella morganii in the gut microbiome and the incidence of major depressive disorder (MDD) in the human host. A bioassay-guided fractionation approach identified bacterially produced metabolites that induced pro-inflammatory immune responses. The metabolites are unusual phospholipids that resemble conventional cardiolipins, in which diethanolamine (DEA) replaces the central glycerol. These molecular chimeras of endogenous metabolites from phospholipid biosynthetic pathways and the industrially produced micropollutant DEA activate TLR2/TLR1 receptors and induce the production of pro-inflammatory cytokines, especially IL-6. Their activity in conventional immunomodulatory assays largely parallels that of immunogenic cardiolipins with conventional structures. The molecular mechanism connecting these chimeric cardiolipins to MDD is supported by other studies and has implications for conditions other than MDD.

Specific Composition Diets and Improvement of Symptoms of Immune-Mediated Inflammatory Diseases in Adulthood-Could the Comparison Between Diets Be Improved?

Diet is considered a possible cofactor, which affects the immune system and potentially causes dysregulation of intestinal homeostasis and inflammation. This study aimed to review the quality of evidence on the effects of specific diet composition on symptoms of immune-mediated inflammatory diseases (IMIDs), including rheumatoid arthritis (RA), spondyloarthritis, multiple sclerosis (MS), inflammatory bowel disease (IBD) [remission maintenance of Crohn's disease and ulcerative colitis], psoriasis and psoriatic arthritis in adult patients. We conducted a review of meta-analyses and Cochrane systematic reviews using PubMed and EMBASE, from inception to September 2024, and Google Scholar. The methodological quality of the meta-analyses was assessed using the AMSTAR 2 rating system. Three Cochrane systematic reviews and eight meta-analyses were evaluated. Some specific composition diets have been shown to reduce the symptoms of RA, IBD, and MS and improve activity parameters in IBD and RA, with critically low or low levels of evidence. The reduction in inflammatory biomarker levels is unclear. This review summarizes the global evidence for specific dietary interventions, mostly with anti-inflammatory properties due to their components, to improve IMID symptoms, clarifying the weaknesses of clinical trials and dietary meta-analyses with critically low or low levels of evidence; and shows the need to use indices such as the Dietary Inflammatory Index, which allows diets to be classified by their pro-inflammatory or anti-inflammatory food content, to better compare diet groups in clinical trials. The difficulty of obtaining high-level evidence from dietary studies is apparent and may delay the application of the results. Clinicians should be aware of the role of diets with anti-inflammatory properties as a complement to pharmacological treatments in IMIDs.

Gut microbial GABA imbalance emerges as a metabolic signature in mild autism spectrum disorder linked to overrepresented Escherichia

Gut microbiota (GM) alterations have been implicated in autism spectrum disorder (ASD), yet the specific functional architecture remains elusive. Here, employing multi-omics approaches, we investigate stool samples from two distinct cohorts comprising 203 children with mild ASD or typical development. In our screening cohort, regression-based analysis for metabolomic profiling identifies an elevated γ-aminobutyric acid (GABA) to glutamate (Glu) ratio as a metabolic signature of ASD, independent of age and gender. In the validating cohort, we affirm the GABA/Glu ratio as an ASD diagnostic indicator after adjusting for geography, age, gender, and specific food-consuming frequency. Integrated analysis of metabolomics, 16S rRNA sequencing, and metagenomics reveals a correlation between overrepresented Escherichia and disrupted GABA metabolism. Furthermore, we observe social behavioral impairments in weaning mice transplanted with E. coli, suggesting a potential link to ASD symptomatology. Collectively, these findings provide insights into potential diagnostic and therapeutic strategies aimed at evaluating and restoring gut microbial neurotransmitter homeostasis.

Maternal Diet and Vulnerability to Cognitive Impairment in Adulthood: Possible Link with Alzheimer's Disease?

BACKGROUND

Aging is the main risk factor for developing cognitive impairments and associated neurodegenerative diseases. However, environmental factors, including nutritional health, are likely to promote or reduce cognitive impairments and neurodegenerative pathologies. An intricate relationship exists between maternal nutrition and adult eating behavior, metabolic phenotype, and cognitive abilities.

SUMMARY

The objective of the present review was to collect available data, suggesting a link between maternal overnutrition and the latter impairment of cognitive functions in the progeny, and to relate this relationship with Alzheimer's disease (AD). Indeed, cognitive impairments are major behavioral signs of AD. We first reviewed studies showing an association between unbalanced maternal diet and cognitive impairments in the progeny in humans and rodent models. Then we looked for cellular and molecular hallmarks which could constitute a breeding ground for AD in those models. With this end, we focused on synaptic dysfunction, altered neurogenesis, neuroinflammation, oxidative stress, and pathological protein aggregation. Finally, we proposed an indirect mechanism linking maternal unbalanced diet and progeny's vulnerability to cognitive impairments and neurodegeneration through promoting metabolic diseases. We also discussed the involvement of progeny's gut microbiota in the maternal diet-induced vulnerability to metabolic and neurodegenerative diseases.

KEY MESSAGES

Further investigations are needed to fully decipher how maternal diet programs the fetus and infant brain. Addressing this knowledge gap would pave the way to precise nutrition and personalized medicine to better handle cognitive impairments in adulthood.

Psychosis of Epilepsy: An Update on Clinical Classification and Mechanism

Epilepsy is a prevalent chronic neurological disorder that can significantly impact patients' lives. The incidence and risk of psychosis in individuals with epilepsy are notably higher than in the general population, adversely affecting both the management and rehabilitation of epilepsy and further diminishing patients' quality of life. This review provides an overview of the classification and clinical features of psychosis of epilepsy, with the aim of offering insights and references for the clinical diagnosis and treatment of various types of psychosis of epilepsy. Additionally, we examine the potential pathophysiological mechanisms underlying the psychosis of epilepsy from three perspectives: neuroimaging, neurobiology, and genetics. The alterations in brain structure and function, neurotransmitters, neuroinflammatory mediators, and genetic factors discussed in this review may offer insights into the onset and progression of psychotic symptoms in epilepsy patients and are anticipated to inform the identification of novel therapeutic targets in the future.

Computational Study Protocol: Leveraging Synthetic Data to Validate a Benchmark Study for Differential Abundance Tests for 16S Microbiome Sequencing Data

Background

Synthetic data's utility in benchmark studies depends on its ability to closely mimic real-world conditions and reproduce results obtained from experimental data. Building on Nearing et al.'s study (1), who assessed 14 differential abundance tests using 38 experimental 16S rRNA datasets in a case-control design, we are generating synthetic datasets that mimic the experimental data to verify their findings. We will employ statistical tests to rigorously assess the similarity between synthetic and experimental data and to validate the conclusions on the performance of these tests drawn by Nearing et al. (1). This protocol adheres to the SPIRIT guidelines, demonstrating how established reporting frameworks can support robust, transparent, and unbiased study planning.

Methods

We replicate Nearing et al.'s (1) methodology, incorporating synthetic data simulated using two distinct tools, mirroring the 38 experimental datasets. Equivalence tests will be conducted on a non-redundant subset of 46 data characteristics comparing synthetic and experimental data, complemented by principal component analysis for overall similarity assessment. The 14 differential abundance tests will be applied to synthetic and experimental datasets, evaluating the consistency of significant feature identification and the number of significant features per tool. Correlation analysis and multiple regression will explore how differences between synthetic and experimental data characteristics may affect the results.

Conclusions

Synthetic data enables the validation of findings through controlled experiments. We assess how well synthetic data replicates experimental data, try to validate previous findings with the most recent versions of the DA methods and delineate the strengths and limitations of synthetic data in benchmark studies. Moreover, to our knowledge this is the first computational benchmark study to systematically incorporate synthetic data for validating differential abundance methods while strictly adhering to a pre-specified study protocol following SPIRIT guidelines, contributing to transparency, reproducibility, and unbiased research.