The Microbiota-Gut-Brain Axis in Psychiatric Disorders

Electroacupuncture intervention alleviates depressive-like behaviors and regulates gut microbiome in a mouse model of depression

Electroacupuncture (EA) is a neuroregulatory therapy for depression. Nonetheless, the effects of EA on the gut microbiome in mice models of depression are not well established. Here, using a chronic unpredictable mild stress (CUMS) model in mice, we evaluated the antidepressant effects of EA and changes in gut microbiota with behavioral tests and 16S rRNA gene sequencing. The results found that EA increased the time spent in the center area of the open-field test and the percentage of sucrose preference and reduced the immobility time in the tail suspension test in CUMS-treated mice. Furthermore, the genus Lachnoclostridium, Ruminococcaceae_UCG-002 and Rikenellaceae_RC9_gut_group were enriched in the CUMS group, which was positively correlated with depressive-like behaviors. Whereas phylum Actinobacteria and genus Allobaculum, Bifidobacterium, Dubosiella, Rikenella and Ileibacterium were enriched in the EA and CUMS + EA groups, all of which were negatively correlated with depressive-like behaviors. This study characterizes gut microbiota under EA treatment and provides new insights into the association of anti-depressive-like effects of EA and gut microbiota.

The gut microbiota and post-traumatic major depression disorder: insights from bidirectional two-sample Mendelian randomization

Background

Exposure to trauma is often associated with an increased incidence of Major Depressive Disorder (MDD), yet the mechanisms underlying MDD development post-trauma remain elusive. The microbiota-gut-brain axis has been implicated in neuropsychiatric disorders, suggesting its potential role in post-traumatic MDD (PTMDD) development. Our study aimed to assess the significance of the gut microbiome-brain interaction in PTMDD.

Methods

We conducted a bidirectional two-sample Mendelian Randomization (MR) analysis to investigate the causal relationship between the gut microbiota and both PTMDD and trauma exposure in MDD. Genome-wide association study (GWAS) summary datasets for PTMDD and trauma exposure in MDD, both derived from the UK Biobank. The PTMDD dataset included 24,090 individuals (13,393 cases and 10,701 controls), while the dataset for trauma exposure in MDD comprised 22,880 participants (13,393 cases and 9,487 controls). Additionally, gut microbiota data from the MiBioGen consortium included 14,306 European individuals across 18 diverse cohorts.

Results

Our research identified a significant negative association between the phylum Verrucomicrobia (odds ratio (OR) [95% confidence interval (CI)] =0.799 [0.684-0.933], P=0.005) and the risk of developing PTMDD, suggesting a protective role for Verrucomicrobia against PTMDD. Conversely, our findings indicate no causal effects of the gut microbiota on trauma exposure in MDD. However, reverse analysis revealed that both PTMDD and MDD influence certain bacterial traits, affecting 5 and 9 bacterial traits, respectively. Moreover, Verrucomicrobia (OR [95% CI] = 1.166 [1.051 - 1.294], P=0.004) was found to be positively impacted by trauma exposure in MDD.

Conclusion

Our findings provide a cause-and-effect relationship between the gut microbiota and PTMDD, contributing to our understanding of the microbiota-gut-brain axis and its role in neuropsychiatric disorder development after trauma. This information provides an opportunity for new treatment and prevention methods which are aimed at the gut-brain interaction.

Exploring the potential of drug repurposing for treating depression

Researchers are interested in drug repurposing or drug repositioning of existing pharmaceuticals because of rising costs and slower rates of new medication development. Other investigations that authorized these treatments used data from experimental research and off-label drug use. More research into the causes of depression could lead to more effective pharmaceutical repurposing efforts. In addition to the loss of neurotransmitters like serotonin and adrenaline, inflammation, inadequate blood flow, and neurotoxins are now thought to be plausible mechanisms. Because of these other mechanisms, repurposing drugs has resulted for treatment-resistant depression. This chapter focuses on therapeutic alternatives and their effectiveness in drug repositioning. Atypical antipsychotics, central nervous system stimulants, and neurotransmitter antagonists have investigated for possible repurposing. Nonetheless, extensive research is required to ensure their formulation, effectiveness, and regulatory compliance.

Anorexia nervosa and bulimia nervosa: a Mendelian randomization study of gut microbiota

Background

Anorexia nervosa (AN) and bulimia nervosa (BN) poses a significant challenge to global public health. Despite extensive research, conclusive evidence regarding the association between gut microbes and the risk of AN and BN remains elusive. Mendelian randomization (MR) methods offer a promising avenue for elucidating potential causal relationships.

Materials and methods

Genome-wide association studies (GWAS) datasets of AN and BN were retrieved from the OpenGWAS database for analysis. Independent single nucleotide polymorphisms closely associated with 196 gut bacterial taxa from the MiBioGen consortium were identified as instrumental variables. MR analysis was conducted utilizing R software, with outlier exclusion performed using the MR-PRESSO method. Causal effect estimation was undertaken employing four methods, including Inverse variance weighted. Sensitivity analysis, heterogeneity analysis, horizontal multivariate analysis, and assessment of causal directionality were carried out to assess the robustness of the findings.

Results

A total of 196 bacterial taxa spanning six taxonomic levels were subjected to analysis. Nine taxa demonstrating potential causal relationships with AN were identified. Among these, five taxa, including Peptostreptococcaceae, were implicated as exerting a causal effect on AN risk, while four taxa, including Gammaproteobacteria, were associated with a reduced risk of AN. Similarly, nine taxa exhibiting potential causal relationships with BN were identified. Of these, six taxa, including Clostridiales, were identified as risk factors for increased BN risk, while three taxa, including Oxalobacteraceae, were deemed protective factors. Lachnospiraceae emerged as a common influence on both AN and BN, albeit with opposing effects. No evidence of heterogeneity or horizontal pleiotropy was detected for significant estimates.

Conclusion

Through MR analysis, we revealed the potential causal role of 18 intestinal bacterial taxa in AN and BN, including Lachnospiraceae. It provides new insights into the mechanistic basis and intervention targets of gut microbiota-mediated AN and BN.

Gastrodin ameliorates depressive-like behaviors via modulating gut microbiota in CUMS-induced mice

PURPOSE

Depression is a psychiatric disorder and the treatment of depression is an urgent problem that need to be solved. Gastrodin (GAS) is a Traditional Chinese Medicine from an orchid and is used for neurological diseases, including depressive disorders.

METHODS

To assess the effect of GAS on gut microbiota of depressive mice, we established a chronic unpredictable mild stress (CUMS)-induced mouse model, and GAS was administered to one group of the mice. Animal behavior experiments were used to detect depressive-like behaviors, and 16 S rRNA gene analysis was applied to detect the gut microbiota of each group. All raw sequences were deposited in the NCBI Sequence Read Archive under accession number SRP491061.

RESULTS

GAS treatment significantly improved depressive-like behaviors as well as the diversity and abundance of the gut microbiota. The depressive-like behaviors of the CUMS-GAS group were improved in different degrees compared with the CUMS group. The linear discriminant analysis (LDA) of the gut microbiota showed that the makeup of the gut microbiota in mice changed dramatically in the CUMS-GAS group, compared with the CUMS group, Bacteroides (LDA = 3.94, P < 0.05) were enriched in the CUMS-GAS group at the genus level. In comparison to the CUMS group, the CUMS-GAS group had a greater concentration numbers of Lactobacillus, Corynebacterium, Staphylococcus, Bacteroides, Psychrobacter, and Alistipes.

CONCLUSION

Our results suggested that GAS improved depressive-like behaviors in mice and impacted the microbial composition of the gut. Our research indicated that dysbiosis of the gut microbiota may be affected by GAS treatment, which improved depressive-like behaviors in the CUMS-induced mouse model of depression.

The effects of heavy metal exposure on brain and gut microbiota: A systematic review of animal studies

The gut-brain axis is a crucial interface between the central nervous system and the gut microbiota. Recent evidence shows that exposure to environmental contaminants, such as heavy metals, can cause dysbiosis in gut microbiota, which may affect the gut-brain communication, impacting aspects of brain function and behavior. This systematic review of the literature aims to evaluate whether deleterious effects on brain function due to heavy metal exposure could be mediated by changes in the gut microbiota profile. Animal studies involving exposure to heavy metals and a comparison with a control group that evaluated neuropsychological outcomes and/or molecular outcomes along with the analysis of microbiota composition were reviewed. The authors independently assessed studies for inclusion, extracted data and assessed risk of bias using the protocol of Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) for preclinical studies. A search in 3 databases yielded 16 eligible studies focused on lead (n = 10), cadmium (n = 1), mercury (n = 3), manganese (n = 1), and combined exposure of lead and manganese (n = 1). The animal species were rats (n = 7), mice (n = 4), zebrafish (n = 3), carp (n = 1) and fruit fly (n = 1). Heavy metals were found to adversely affect cognitive function, behavior, and neuronal morphology. Moreover, heavy metal exposure was associated with changes in the abundance of specific bacterial phyla, such as Firmicutes and Proteobacteria, which play crucial roles in gut health. In some studies, these alterations were correlated with learning and memory impairments and mood disorders. The interplay of heavy metals, gut microbiota, and brain suggests that heavy metals can induce direct brain alterations and indirect effects through the microbiota, contributing to neurotoxicity and the development of neuropsychological disorders. However, the small number of papers under review makes it difficult to draw definitive conclusions. Further research is warranted to unravel the underlying mechanisms and evaluate the translational implications for human health.

Effectiveness of Psychobiotics in the Treatment of Psychiatric and Cognitive Disorders: A Systematic Review of Randomized Clinical Trials

In this study, a systematic review of randomized clinical trials conducted from January 2000 to December 2023 was performed to examine the efficacy of psychobiotics-probiotics beneficial to mental health via the gut-brain axis-in adults with psychiatric and cognitive disorders. Out of the 51 studies involving 3353 patients where half received psychobiotics, there was a notably high measurement of effectiveness specifically in the treatment of depression symptoms. Most participants were older and female, with treatments commonly utilizing strains of Lactobacillus and Bifidobacteria over periods ranging from 4 to 24 weeks. Although there was a general agreement on the effectiveness of psychobiotics, the variability in treatment approaches and clinical presentations limits the comparability and generalization of the findings. This underscores the need for more personalized treatment optimization and a deeper investigation into the mechanisms through which psychobiotics act. The research corroborates the therapeutic potential of psychobiotics and represents progress in the management of psychiatric and cognitive disorders.

Gut Microbiota Moderates Multimodal Brain Structure-Function Integration and Behavioral Cognition in Growth Hormone Deficient Children

INTRODUCTION

Previous brain studies of growth hormone deficiency (GHD) often used single-modal neuroimaging, missing the complexity captured by multimodal data. Growth hormone affects gut microbiota and metabolism in GHD. However, from a gut-brain axis (GBA) perspective, the relationship between abnormal GHD brain development and microbiota alterations remains unclear. The ultimate goal is to uncover the manifestations underlying GBA abnormalities in GHD and idiopathic short stature (ISS).

METHODS

Participants included 23 GHD and 25 ISS children. The fusion independent component analysis was applied to integrate multimodal brain data (high-resolution structural, diffusion tensor, and resting-state functional MRI) covering regional homogeneity (ReHo), amplitude of low frequency fluctuations (ALFF), and white matter fractional anisotropy (FA). Gut microbiome diversity and metabolites were analyzed using 16S sequencing and proton nuclear magnetic resonance (1H-NMR). Associations between multimodal neuroimaging and cognition were assessed using moderation analysis.

RESULTS

Six independent components (IC) of ReHo, ALFF, and FA differed significantly between GHD and ISS patients, with three functional components linked to the processing speed index. GHD individuals showed higher levels of acetate, nicotinate, and lysine in microbiota metabolism. Higher alpha diversity in GHD strengthened connections between ReHo-IC1, ReHo-IC5, ALFF-IC1, and the processing speed index, while increasing agathobacter levels in ISS weakened the link between ALFF-IC1 and the speech comprehension index.

CONCLUSIONS

Our findings uncover differing brain structure and functional fusion in GHD, alongside microbiota metabolism of short-chain fatty acids. Additionally, microbiome influences connections between neuroimaging and cognition, offering insight into diverse GBA patterns in GHD and ISS, enhancing our understanding of the disease's pathophysiology and interventions.

Neuroinflammation and Schizophrenia: New Therapeutic Strategies through Psychobiotics, Nanotechnology, and Artificial Intelligence (AI)

The prevalence of schizophrenia, affecting approximately 1% of the global population, underscores the urgency for innovative therapeutic strategies. Recent insights into the role of neuroinflammation, the gut-brain axis, and the microbiota in schizophrenia pathogenesis have paved the way for the exploration of psychobiotics as a novel treatment avenue. These interventions, targeting the gut microbiome, offer a promising approach to ameliorating psychiatric symptoms. Furthermore, advancements in artificial intelligence and nanotechnology are set to revolutionize psychobiotic development and application, promising to enhance their production, precision, and effectiveness. This interdisciplinary approach heralds a new era in schizophrenia management, potentially transforming patient outcomes and offering a beacon of hope for those afflicted by this complex disorder.

The Power of Psychobiotics in Depression: A Modern Approach through the Microbiota-Gut-Brain Axis: A Literature Review

The microbiota-gut-brain (MGB) axis is a complex communication network linking the gut, microbiota, and brain, influencing various aspects of health and disease. Dysbiosis, a disturbance in the gut microbiome equilibrium, can significantly impact the MGB axis, leading to alterations in microbial composition and function. Emerging evidence highlights the connection between microbiota alterations and neurological and psychiatric disorders, including depression. This review explores the potential of psychobiotics in managing depressive disorders, emphasizing their role in restoring microbial balance and influencing the MGB axis. Psychobiotics exhibit positive effects on the intestinal barrier, immune response, cortisol levels, and the hypothalamic-pituitary-adrenal (HPA) axis. Studies suggest that probiotics may serve as an adjunct therapy for depression, especially in treatment-resistant cases. This review discusses key findings from studies on psychobiotics interventions, emphasizing their impact on the gut-brain axis and mental health. The increasing acceptance of the expanded concept of the MGB axis underscores the importance of microorganisms in mental well-being. As our understanding of the microbiome's role in health and disease grows, probiotics emerge as promising agents for addressing mental health issues, providing new avenues for therapeutic interventions in depressive disorders.

Advances in molecular mechanisms and therapeutic strategies for central nervous system diseases based on gut microbiota imbalance

BACKGROUD

Central nervous system (CNS) diseases pose a serious threat to human health, but the regulatory mechanisms and therapeutic strategies of CNS diseases need to be further explored. It has been demonstrated that the gut microbiota (GM) is closely related to CNS disease. GM structure disorders, abnormal microbial metabolites, intestinal barrier destruction and elevated inflammation exist in patients with CNS diseases and promote the development of CNS diseases. More importantly, GM remodeling alleviates CNS pathology to some extent.

AIM OF REVIEW

Here, we have summarized the regulatory mechanism of the GM in CNS diseases and the potential treatment strategies for CNS repair based on GM regulation, aiming to provide safer and more effective strategies for CNS repair from the perspective of GM regulation.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The abundance and composition of GM is closely associated with the CNS diseases. On the basis of in-depth analysis of GM changes in mice with CNS disease, as well as the changes in its metabolites, therapeutic strategies, such as probiotics, prebiotics, and FMT, may be used to regulate GM balance and affect its microbial metabolites, thereby promoting the recovery of CNS diseases.

Hawaiian native herb Mamaki prevents dementia by ameliorating neuropathology and repairing neurons in four different mouse models of neurodegenerative diseases

Neurodegenerative diseases including Alzheimer's disease, frontotemporal dementia, and dementia with Lewy bodies are age-related disorders and the main cause of dementia. They are characterized by the cerebral accumulation of Aβ, tau, α-synuclein, and TDP-43. Because the accumulation begins decades before disease onset, treatment should be started in the preclinical stage. Such intervention would be long-lasting, and therefore, prophylactic agents should be safe, non-invasively taken by the patients, and inexpensive. In addition, the agents should be broadly effective against etiologic proteins and capable of repairing neurons damaged by toxic oligomers. These requirements are difficult to meet with single-ingredient pharmaceuticals but may be feasible by taking proper diets composed of multiple ingredients. As a source of such diets, we focused on the Hawaiian native herb Mamaki. From its dried leaves and fruits, we made three preparations: hot water extract of the leaves, non-extracted simple crush powder of the leaves, and simple crush powder of the fruits, and examined their effects on the cognitive function and neuropathologies in four different mouse models of neurodegenerative dementia. Hot water extract of the leaves attenuated neuropathologies, restored synaptophysin levels, suppressed microglial activation, and improved memory when orally administered for 1 month. Simply crushed leaf powder showed a higher efficacy, but simply crushed fruit powder displayed the strongest effects. Moreover, the fruit powder significantly enhanced the levels of brain-derived neurotrophic factor expression and neurogenesis, indicating its ability to repair neurons. These results suggest that crushed Mamaki leaves and fruits are promising sources of dementia-preventive diets.

Markers of intestinal barrier damage in patients with chronic insomnia disorder

Objective

Insomnia disorder stands out as one of the prevalent clinical sleep and psychiatric disorders. Prior research has unequivocally demonstrated variations in the diversity and abundance of gut microbiota among individuals with insomnia disorder. These alterations may play a direct or indirect role in the onset and progression of insomnia disorder by compromising the integrity of the intestinal barrier. This study aims to evaluate the impairment of the intestinal barrier in individuals with insomnia disorder by scrutinizing the serum functionality of this barrier.

Materials and methods

45 patients with chronic insomnia disorder and 30 matched healthy volunteers were meticulously selected based on inclusion criteria. ELISA technology was employed to measure serum levels of diamine oxidase (DAO), D-lactic acid (D-LA), intestinal fatty acid binding protein (I-FABP), and endothelin (ET). Spearman correlation analysis was used to explore the relationship between intestinal mucosal markers and clinical characteristics. Data were analyzed using SPSS 26.0.

Results

Compared to the healthy control group, the insomnia disorder group exhibited significantly elevated scores on subjective mood and sleep scales (GAD-7, PHQ-9, HAMA, HAMD, PSQI, and ISI) (P < 0.05). Overnight PSG indicated a notable increase in bed time, total wake time, sleep onset latency, and wake after sleep onset in individuals with insomnia disorder. Additionally, there was a decrease in sleep efficiency and alterations in sleep structure (increased proportion of N1 and N3 stages, prolonged N1 stage) (P < 0.05). The chronic insomnia disorder group displayed significantly reduced concentrations of serum DAO, D-LA, I-FABP, and ET (P < 0.05). Furthermore, significant positive correlations were identified between intestinal epithelial barrier markers and sleep efficiency, while negative correlations were found with wake after sleep onset, total wake time, PSQI, HAMA, and HAMD. Additionally, D-LA levels were significantly positively correlated with ET concentrations.

Conclusion

Individuals with chronic insomnia disorder manifest disruptions in sleep structure, heightened susceptibility to anxiety and depressive moods, and impaired intestinal barrier function. These findings suggest that the occurrence and development of insomnia disorder may be linked to the impairment of the intestinal barrier.

A Mendelian randomization investigation of the causal association between the gut microbiota and sleep disorders

Background

Increasing numbers of people are suffering from sleep disorders. The gut microbiota of these individuals differs significantly. However, no reports are available on the causal associations between specific gut microbiota and sleep disorders.

Methods

Data on gut genera were obtained from the MiBioGen consortium. Twenty-four cohorts with 18,340 individuals of European origin were included. Sleep disorder data, which included 216,454 European individuals, were retrieved from the FinnGen Biobank. Subsequently, two-sample Mendelian randomization was performed to analyze associations between sleep disorders and specific components of the gut microbiota.

Results

Inverse variance weighting (IVW) revealed a negative correlation between Coprobacter and sleep disorders (OR = 0.797, 95% CI = 0.66-0.96, and p = 0.016), a positive correlation between Lachnospiraceae and sleep disorders (OR = 1.429, 95% CI = 1.03-1.98, and p = 0.032), a negative association between Oscillospira and sleep disorders (OR = 0.745, 95% CI = 0.56-0.98, and p = 0.038), and a negative association between Peptococcus and sleep disorders (OR = 0.858, 95% CI = 0.74-0.99, p = 0.039).

Conclusion

A significant causal relationship was found between four specific gut microbiota and sleep disorders. One family, Lachnospiraceae, was observed to increase the risk of sleep disorders, while three genera, namely, Coprobacter, Oscillospira, and Peptococcus, could reduce the risk of sleep disorders. However, further investigations are needed to confirm the specific mechanisms by which the gut microbiota affects sleep.

Cold exposure, gut microbiota and health implications: A narrative review

Temperature has been recognized as an important environmental factor affecting the composition and function of gut microbiota (GM). Although research on high-temperature impacts has been well studied, knowledge about the effect of cold exposure on GM remains limited. This narrative review aims to synthesize the latest scientific findings on the impact of cold exposure on mammalian GM, and its potential health implications. Chronic cold exposure could disrupt the α-diversity and the composition of GM in both experimental animals and wild-living hosts. Meanwhile, cold exposure could impact gut microbial metabolites, such as short-chain fatty acids. We also discussed plausible biological pathways and mechanisms by which cold-induced changes may impact host health, including metabolic homeostasis, fitness and thermogenesis, through the microbiota-gut-brain axis. Intriguingly, alterations in GM may provide a tool for favorably modulating the host response to the cold temperature. Finally, current challenges and future perspectives are discussed, emphasizing the need for translational research in humans. GM could be manipulated by utilizing nutritional strategies, such as probiotics and prebiotics, to deal with cold-related health issues and enhance well-being in populations living or working in cold environments.

Review of research progress on intestinal microbiota based on metabolism and inflammation for depression

Depression is a prevalent mental illness, affecting a significant portion of the global population. Recent research has highlighted the crucial role of the gut microbiota in both metabolic and central nervous health. By reviewing literature from various databases, including Pubmed, Science Direct, Web of Science, and Scopus, spanning the years 2005-2023, a comprehensive search was conducted using keywords such as "Depression" and "Gut Microbiota". The gut microbiota acts as a "second brain" in humans and can communicate bidirectionally with the brain through the Brain-gut-microbiota axis pathway. This communication involves the immune and nervous systems. However, there are challenges in detecting and treating depression effectively. To address these limitations, researchers have been exploring the relationship between gut microbiota and depression. Studies have shown that gut microbial metabolites, such as lipopolysaccharides and short-chain fatty acids, can induce pro-inflammatory cytokines that contribute to neuroinflammation and increase the risk of depression. The kynurenine pathway, triggered by gut microbial metabolites, has also been associated with neuroinflammation. Thus, investigating these microbial metabolites can provide insights into depression treatment. This review focuses on analyzing the connection between gut microbial metabolites, inflammation, and depression. It explores novel mechanisms contributing to depression, specifically focusing on the mediation of inflammation through the release of pro-inflammatory cytokines. The objective is to provide valuable insights into the mechanisms underlying depression and to propose potential treatments.

Causal relationship between the gut microbiota and insomnia: a two-sample Mendelian randomization study

Background

Changes in the gut microbiota are closely related to insomnia, but the causal relationship between them is not yet clear.

Objective

To clarify the relationship between the gut microbiota and insomnia and provide genetic evidence for them, we conducted a two-sample Mendelian randomization study.

Methods

We used a Mendelian randomized two-way validation method to discuss the causal relationship. First, we downloaded the data of 462,341 participants relating to insomnia, and the data of 18,340 participants relating to the gut microbiota from a genome-wide association study (GWAS). Then, we used two regression models, inverse-variance weighted (IVW) and MR-Egger regression, to evaluate the relationship between exposure factors and outcomes. Finally, we took a reverse MR analysis to assess the possibility of reverse causality.

Results

The combined results show 19 gut microbiotas to have a causal relationship with insomnia (odds ratio (OR): 1.03; 95% confidence interval (CI): 1.01, 1.05; p=0.000 for class. Negativicutes; OR: 1.03; 95% CI: 1.01, 1.05; p=0.000 for order.Selenomonadales; OR: 1.01; 95% CI: 1.00, 1.02; p=0.003 for genus.RikenellaceaeRC9gutgroup). The results were consistent with sensitivity analyses for these bacterial traits. In reverse MR analysis, we found no statistical difference between insomnia and these gut microbiotas.

Conclusion

This study can provide a new direction for the causal relationship between the gut microbiota (class.Negativicutes, order.Selenomonadales, genus.Lactococcus) and insomnia and the treatment or prevention strategies of insomnia.

Microbiome dynamics in rheumatic diseases

PURPOSE OF REVIEW

Rheumatic disease are characterized by their autoimmune nature, frequently affecting joints, bones, muscles, blood vessels, and connective tissues. The onset of these conditions typically unfolds gradually and subtly. It is noteworthy that individuals with rheumatic diseases often experience shifts in their microbiome, specifically on mucosal surfaces. The purpose of this review is to delve into the intricate interplay between the microbiome, encompassing bacteria, viruses and fungi, and its role in the development and aggravation of various rheumatic diseases. Additionally, it aims to offer insights into microbiome-centered therapeutic approaches for patients in the field of rheumatology.

RECENT FINDINGS

The advent of next-generation sequencing has significantly improved our understanding of microbiome changes. Numerous studies have consistently revealed a strong link between rheumatism and the microbiome, especially in the oral and gut microbiota.

SUMMARY

A deeper comprehension of the microbiome's connection to rheumatism holds potential for enhancing disease diagnosis and treatment. Targeted therapeutic approaches, including probiotics, fecal microbiota transplantation, and combination therapies with medications, offer promising avenues for disease management.

Radix Bupleuri aqueous extract attenuates MK801-induced schizophrenia-like symptoms in mice: Participation of intestinal flora

Schizophrenia (SCZ) is a psychotic mental disorder characterized by cognitive, behavioral, and social impairments. However, current pharmacological treatment regimens are subpar in terms of effectiveness. This study aimed to investigate the function of Radix Bupleuri aqueous extract in SCZ in mouse models. The SCZ mouse model was established by MK-801 injection and feeding of Radix Bupleuri aqueous extract or combined antibiotics. Radix Bupleuri aqueous extract significantly improved the aberrant behaviors and neuronal damage in SCZ mice, upregulated SYP and PSD-95 expression and BDNF levels in hippocampal homogenates, down-regulated DA and 5-HT levels, and suppressed microglial activation in SCZ mice. Moreover, Radix Bupleuri aqueous extract improved the integrity of the intestinal tract barrier. The 16 S rRNA sequencing of feces showed that Radix Bupleuri extract modulated the composition of gut flora. Lactobacillus abundance was decreased in SCZ mice and reversed by Radix Bupleuri aqueous extract administration which exhibited a significant negative correlation with IL-6, IL-1β, DA, and 5-HT, and a significant positive correlation with BDNF levels in hippocampal tissues. The abundance of Parabacteroides and Alloprevotella was increased in SCZ mice. It was reversed by Radix Bupleuri aqueous extract administration, which exhibited a positive correlation with IL-6, IL-1β, and 5-HT and a negative correlation with BDNF. In conclusion, Radix Bupleuri aqueous extract attenuates the inflammatory response in hippocampal tissues and modulates neurotransmitter levels, exerting its neuroprotective effect in SCZ. Meanwhile, the alteration of intestinal flora may be involved in this process, which is expected to be an underlying therapeutic option in treating SCZ.

Between Dysbiosis, Maternal Immune Activation and Autism: Is There a Common Pathway?

Autism spectrum disorder (ASD) is a neuropsychiatric condition characterized by impaired social interactions and repetitive stereotyped behaviors. Growing evidence highlights an important role of the gut-brain-microbiome axis in the pathogenesis of ASD. Research indicates an abnormal composition of the gut microbiome and the potential involvement of bacterial molecules in neuroinflammation and brain development disruptions. Concurrently, attention is directed towards the role of short-chain fatty acids (SCFAs) and impaired intestinal tightness. This comprehensive review emphasizes the potential impact of maternal gut microbiota changes on the development of autism in children, especially considering maternal immune activation (MIA). The following paper evaluates the impact of the birth route on the colonization of the child with bacteria in the first weeks of life. Furthermore, it explores the role of pro-inflammatory cytokines, such as IL-6 and IL-17a and mother's obesity as potentially environmental factors of ASD. The purpose of this review is to advance our understanding of ASD pathogenesis, while also searching for the positive implications of the latest therapies, such as probiotics, prebiotics or fecal microbiota transplantation, targeting the gut microbiota and reducing inflammation. This review aims to provide valuable insights that could instruct future studies and treatments for individuals affected by ASD.

Pick fecal microbiota transplantation to enhance therapy for major depressive disorder

In recent years, fecal microbiota transplantation (FMT) has emerged as a promising therapy for major depressive disorder (MDD). The goal of the operation is to restore a healthy gut microbiota by introducing feces from a healthy donor into the recipient's digestive system. The brain-gut axis is thought to have a significant role in regulating mood, behavior, and cognition, which supports the use of FMT in the treatment of MDD. Numerous studies have shown a correlation between abnormalities of the gut microbiota and MDD, whereas FMT has demonstrated the potential to restore microbial equilibrium. While FMT has shown encouraging results, it is crucial to highlight the potential hazards and limits inherent to this therapeutic approach. Stool donor-to-recipient disease transfer is a concern of FMT. Furthermore, it still needs to be determined what effect FMT has on the gut microbiota and the brain in the long run. This literature review provides an overview of the possible efficacy of FMT as a therapeutic modality for MDD. There is hope for patients who have not reacted well to typical antidepressant therapy since FMT may become an invaluable tool in the treatment of MDD as researchers continue to examine the relationship between gut microbiota and MDD.

Ferroptosis: a new antidepressant pharmacological mechanism

The incidence rate of depression, a mental disorder, is steadily increasing and has the potential to become a major global disability factor. Given the complex pathological mechanisms involved in depression, the use of conventional antidepressants may lead to severe complications due to their side effects. Hence, there is a critical need to explore the development of novel antidepressants. Ferroptosis, a newly recognized form of cell death, has been found to be closely linked to the onset of depression. Several studies have indicated that certain active ingredients can ameliorate depression by modulating the ferroptosis signaling pathway. Notably, traditional Chinese medicine (TCM) active ingredients and TCM prescriptions have demonstrated promising antidepressant effects in previous investigations owing to their unique advantages in antidepressant therapy. Building upon these findings, our objective was to review recent relevant research and provide new insights and directions for the development and application of innovative antidepressant strategies.

The interplay between gut microbiota, short-chain fatty acids, and implications for host health and disease

Short-chain fatty acids (SCFAs) - acetate, propionate, and butyrate - are important bacterial fermentation metabolites regulating many important aspects of human physiology. Decreases in the concentrations of any or multiple SCFAs are associated with various detrimental effects to the host. Previous research has broadly focused on gut microbiome produced SCFAs as a group, with minimal distinction between acetate, propionate, and butyrate independently, each with significantly different host effects. In this review, we comprehensively delineate the roles of these SCFAs with emphasis on receptor affinity, signaling pathway involvement, and net host physiologic effects. Butyrate is highlighted due to its unique role in gastrointestinal-associated functions, especially maintaining gut barrier integrity. Butyrate functions by promoting epithelial tight junctions, serving as fuel for colonocyte ATP production, and modulating the immune system. Interaction with the immune system occurs locally in the gastrointestinal tract and systemically in the brain. Investigation into research conducted on butyrate production pathways and specific bacterial players involved highlights a unique risk associated with use of gram-positive targeted antibiotics. We review and discuss evidence showing the relationship between the butyrate-producing gram-positive genus, Roseburia, and susceptibility to commonly prescribed, widely used gram-positive antibiotics. Considering gut microbiome implications when choosing antibiotic therapy may benefit health outcomes in patients.

The Common Denominators of Parkinson's Disease Pathogenesis and Methamphetamine Abuse

The pervasiveness and mortality associated with methamphetamine abuse have doubled during the past decade, suggesting a possible worldwide substance use crisis. Epitomizing the pathophysiology and toxicology of methamphetamine abuse proclaims severe signs and symptoms of neurotoxic and neurobehavioral manifestations in both humans and animals. Most importantly, chronic use of this drug enhances the probability of developing neurodegenerative diseases manifolds. Parkinson's disease is one such neurological disorder, which significantly and evidently not only shares a number of toxic pathogenic mechanisms induced by methamphetamine exposure but is also interlinked both structurally and genetically. Methamphetamine-induced neurodegeneration involves altered dopamine homeostasis that promotes the aggregation of α-synuclein protofibrils in the dopaminergic neurons and drives these neurons to make them more vulnerable to degeneration, as recognized in Parkinson's disease. Moreover, the pathologic mechanisms such as mitochondrial dysfunction, oxidative stress, neuroinflammation and decreased neurogenesis detected in methamphetamine abusers dramatically resemble to what is observed in Parkinson's disease cases. Therefore, the present review comprehensively cumulates a holistic illustration of various genetic and molecular mechanisms putting across the notion of how methamphetamine administration and intoxication might lead to Parkinson's disease-like pathology and Parkinsonism.

Children autism spectrum disorder and gut microbiota: A bibliometric and visual analysis from 2000 to 2023

Autism spectrum disorder (ASD) has evolved from a narrow and rare childhood-onset disorder to a widely publicized and researched lifelong disease recognized as common and significantly heterogeneous. Researchers have suggested that gastrointestinal symptoms in ASD may be a manifestation of an underlying inflammatory process. However, there is a lack of bibliometric analysis of ASD and gut microbiota in children. Accordingly, this study conducts a bibliometric analysis of ASD and gut microbiota in children from 2000 to 2023, explores the current status and cutting-edge trends in the field of ASD and gut microbiota in children, and identifies new directions for future research. The literature on ASD and gut microbiota in children was screened using the Web of Science Core Collection from 2000 to 2023. Annual publications, countries, institutions, authors, journals, keywords, and references were visualized and analyzed using CiteSpace 5.8. R3 and VOSviewer1.6.18. This study included 1071 publications. Since the beginning of 2011, the overall number of articles shows an upward trend. The most productive country and institution are the United States and the University of California system, respectively. The most frequently cited author is Kang Dae-Wook, with 790 citations, who has contributed significantly to this field. Timothy Dinan is the most prolific author, with 34 articles. The journal with the most published articles on this topic is Nutrients, whereas PLOS One is the most cited journal. The most used keyword is "gut microbiota," and the reference for the highest outbreak intensity is Hsiao. The research hotspots and trends predicted in this study provide a reference for further in-depth research in this field.

Calcium-sensing receptor alleviates gut damage caused by endotoxemia by regulating gut microbiota

Background

Growing evidence points to an association between the gut microbiota and neonatal diseases. Calcium-sensing receptor (CaSR) is a major modulator of tissue responses associated with calcium homeostasis and is highly expressed in the mammalian gut. CaSR may affect the composition and balance of the intestinal microenvironment.

Methods

Neonatal rats were randomized to the control, lipopolysaccharide (LPS), CaSR agonist, and CaSR inhibitor groups. The intestinal contents of neonatal rats were collected within 24 hours or 7 days after intervention. Then, 16S rRNA short amplicon sequencing was used to analyze biological information and the richness and diversity of individual taxa.

Results

LPS aggravated intestinal injury. The CaSR agonist alleviated injury, and the inhibitor further enhance intestinal injury. Activation of CaSR enhanced the diversity of the gut microbiota and the abundance of Lactobacillus. The lowest abundance of Firmicutes and the highest abundance of Bacteroidetes were found in the agonist group. CaSR impacted the bacterial species in rats with endotoxemia, and Akkermansia had the greatest effect on the differences among groups.

Conclusions

Activation of CaSRs could enhance the species richness and β-diversity of the gut microbiota and alter the abundance of many taxa. This could attenuate LPS-induced gut injury by modulating the gut microbiota.

Peripheral immunity and risk of incident brain disorders: a prospective cohort study of 161,968 participants

Whether peripheral immunity prospectively influences brain health remains controversial. This study aims to investigate the longitudinal associations between peripheral immunity markers with incident brain disorders. A total of 161,968 eligible participants from the UK Biobank were included. We investigated the linear and non-linear effects of peripheral immunity markers including differential leukocytes counts, their derived ratios and C-reactive protein (CRP) on the risk of dementia, Parkinson's disease (PD), stroke, schizophrenia, bipolar affective disorder (BPAD), major depressive disorder (MDD) and anxiety, using Cox proportional hazard models and restricted cubic spline models. Linear regression models were used to explore potential mechanisms driven by brain structures. During a median follow-up of 9.66 years, 16,241 participants developed brain disorders. Individuals with elevated innate immunity markers including neutrophils, monocytes, platelets, neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII) had an increased risk of brain disorders. Among these markers, neutrophils exhibited the most significant correlation with risk of dementia (hazard ratio 1.08, 95% confidence interval 1.04-1.12), stroke (HR 1.06, 95% CI 1.03-1.09), MDD (HR 1.13, 95% CI 1.10-1.16) and anxiety (HR 1.07, 95% CI 1.04-1.10). Subgroup analysis revealed age-specific and sex-specific associations between innate immunity markers with risk of dementia and MDD. Neuroimaging analysis highlighted the associations between peripheral immunity markers and alterations in multiple cortical, subcortical regions and white matter tracts, typically implicated in dementia and psychiatric disorders. These findings support the hypothesis that neuroinflammation is important to the etiology of various brain disorders, offering new insights into their potential therapeutic approaches.

Gut liver brain axis in diseases: the implications for therapeutic interventions

Gut-liver-brain axis is a three-way highway of information interaction system among the gastrointestinal tract, liver, and nervous systems. In the past few decades, breakthrough progress has been made in the gut liver brain axis, mainly through understanding its formation mechanism and increasing treatment strategies. In this review, we discuss various complex networks including barrier permeability, gut hormones, gut microbial metabolites, vagus nerve, neurotransmitters, immunity, brain toxic metabolites, β-amyloid (Aβ) metabolism, and epigenetic regulation in the gut-liver-brain axis. Some therapies containing antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), polyphenols, low FODMAP diet and nanotechnology application regulate the gut liver brain axis. Besides, some special treatments targeting gut-liver axis include farnesoid X receptor (FXR) agonists, takeda G protein-coupled receptor 5 (TGR5) agonists, glucagon-like peptide-1 (GLP-1) receptor antagonists and fibroblast growth factor 19 (FGF19) analogs. Targeting gut-brain axis embraces cognitive behavioral therapy (CBT), antidepressants and tryptophan metabolism-related therapies. Targeting liver-brain axis contains epigenetic regulation and Aβ metabolism-related therapies. In the future, a better understanding of gut-liver-brain axis interactions will promote the development of novel preventative strategies and the discovery of precise therapeutic targets in multiple diseases.

Role of the gut-brain axis via the subdiaphragmatic vagus nerve in stress resilience of 3,4-methylenedioxymethamphetamine in mice exposed to chronic restrain stress

3,4-Methylenedioxymethamphetamine (MDMA) is the most widely used illicit substance worldwide. Nevertheless, recent observational studies demonstrated that lifetime MDMA use among U.S. adults was associated with a lower risk of depression and suicide thoughts. We recently reported that the gut-brain axis may contribute to MDMA-induced stress resilience in mice. To further explore this, we investigated the effects of subdiaphragmatic vagotomy (SDV) in modulating the stress resilience effects of MDMA in mice subjected to chronic restrain stress (CRS). Pretreatment with MDMA (10 mg/kg/day for 14 days) blocked anhedonia-like behavior and reduced expression of synaptic proteins and brain-derived neurotrophic factor in the prefrontal cortex (PFC) of CRS-exposed mice. Interestingly, SDV blocked the beneficial effects of MDMA on these alterations in CRS-exposed mice. Analysis of gut microbiome revealed alterations in four measures of α-diversity between the sham + MDMA + CRS group and the SDV + MDMA + CRS group. Moreover, specific microbes differed between the vehicle + CRS group and the MDMA + CRS group, and further differences in microbial composition were observed among all four groups. Untargeted metabolomics analysis showed that SDV prevented the increase in plasma levels of three compounds [lactic acid, 1-(2-hydroxyethyl)-2,2,6-tetramethyl-4-piperidinol, 8-acetyl-7-hydroxyvumaline] observed in the sham + MDMA + CRS group. Interestingly, positive correlations were found between the plasma levels of two of these compounds and the abundance of several microbes across all groups. In conclusion, our data suggest that the gut-brain axis via the subdiaphragmatic vagus nerve might contribute to the stress resilience of MDMA.

Recent advances in anxiety disorders: Focus on animal models and pathological mechanisms

Anxiety disorders have become one of the most severe psychiatric disorders, and the incidence is increasing every year. They impose an extraordinary personal and socioeconomic burden. Anxiety disorders are influenced by multiple complex and interacting genetic, psychological, social, and environmental factors, which contribute to disruption or imbalance in homeostasis and eventually cause pathologic anxiety. The selection of a suitable animal model is important for the exploration of disease etiology and pathophysiology, and the development of new drugs. Therefore, a more comprehensive understanding of the advantages and limitations of existing animal models of anxiety disorders is helpful to further study the underlying pathological mechanisms of the disease. This review summarizes animal models and the pathogenesis of anxiety disorders, and discusses the current research status to provide insights for further study of anxiety disorders.

Causal relationship between gut microbiota and immune thrombocytopenia: a Mendelian randomization study of two samples

Background

Some observational studies have shown that immune thrombocytopenia (ITP) is highly associated with the alteration-composition of gut microbiota. However, the causality of gut microbiota on ITP has not yet been determined.

Methods

Based on accessible summary statistics of the genome-wide union, the latent connection between ITP and gut microbiota was estimated using bi-directional Mendelian randomization (MR) and multivariable MR (MVMR) analyses. Inverse variance weighted (IVW), weighted median analyses, and MR-Egger regression methods were performed to examine the causal correlation between ITP and the gut microbiota. Several sensitivity analyses verified the MR results. The strength of causal relationships was evaluated using the MR-Steiger test. MVMR analysis was undertaken to test the independent causal effect. MR analyses of reverse direction were made to exclude the potential of reverse correlations. Finally, GO enrichment analyses were carried out to explore the biological functions.

Results

After FDR adjustment, two microbial taxa were identified to be causally associated with ITP (PFDR < 0.10), namely Alcaligenaceae (PFDR = 7.31 × 10-2) and Methanobacteriaceae (PFDR = 7.31 × 10-2). In addition, eight microbial taxa were considered as potentially causal features under the nominal significance (P < 0.05): Actinobacteria, Lachnospiraceae, Methanobacteria, Bacillales, Methanobacteriales, Coprococcus2, Gordonibacter, and Veillonella. According to the reverse-direction MR study findings, the gut microbiota was not significantly affected by ITP. There was no discernible horizontal pleiotropy or instrument heterogeneity. Finally, GO enrichment analyses showed how the identified microbial taxa participate in ITP through their underlying biological mechanisms.

Conclusion

Several microbial taxa were discovered to be causally linked to ITP in this MR investigation. The findings improve our understanding of the gut microbiome in the risk of ITP.

The Potential Role of Fecal Microbiota Transplant in the Reversal or Stabilization of Multiple Sclerosis Symptoms: A Literature Review on Efficacy and Safety

Multiple sclerosis (MS) affects millions of people worldwide, and recent data have identified the potential role of the gut microbiome in inducing autoimmunity in MS patients. To investigate the potential of fecal microbiota transplant (FMT) as a treatment option for MS, we conducted a comprehensive literature search (PubMed/Medline, Embase, Web of Science, Scopus, and Cochrane) and identified five studies that involved 15 adult MS patients who received FMT for gastrointestinal symptoms. The primary outcome of this review was to assess the effect of FMT in reversing and improving motor symptoms in MS patients, while the secondary outcome was to evaluate the safety of FMT in this patient population. Our findings suggest that all 15 patients who received FMT experienced improved and reversed neurological symptoms secondary to MS. This improvement was sustained even in follow-up years, with no adverse effects observed. These results indicate that FMT may hold promise as a treatment option for MS, although further research is necessary to confirm these findings.

The impact of electroacupuncture on anxiety-like behavior and gut microbiome in a mouse model of chronic restraint stress

Introduction

Electroacupuncture (EA) is a beneficial physiotherapy approach for addressing neuropsychiatric disorders. Nevertheless, the impact of EA on the gut microbiome in relation to anxiety disorders remains poorly understood.

Methods

To address this gap, we conducted a study using a chronic restraint stress (CRS) mouse model to investigate the anti-anxiety outcome of EA and its influence on gut microbiota. Our research involved behavioral tests and comprehensive sequencing of full-length 16S rRNA microbiomes.

Results

Our findings revealed that CRS led to significant anxiety-like behaviors and an imbalance in the gut microbiota. Specifically, we identified 13 species that exhibited changes associated with anxiety-like behaviors. Furthermore, EA partially alleviated both behaviors related to anxiety and the dysbiosis induced by CRS.

Discussion

In summary, this study sheds light on the alterations in gut microbiota species resulting from CRS treatment and brings new light into the connection between EA's anti-anxiety effects and the gut microbiota.

The effects of Lactobacillus reuteri microcapsules on radiation-induced brain injury by regulating the gut microenvironment

A radiation-induced brain injury (RIBI) is a major adverse event following radiotherapy of malignant tumors. RIBI would affect cognitive function, leading to a series of complications and even death. However, the pathogenesis of RIBI is still unclear, and it still lacks specific therapeutic drugs. The gut-brain bidirectional communication may be mediated by various microbiota and metabolites in the gastrointestinal tract. Probiotics are closely related to physiological health. The theory of the gut-brain axis provides us with a new idea to improve the gut microenvironment by supplementing probiotics against RIBI. Here, Lactobacillus reuteri microcapsules (LMCs) were prepared, which were predominantly irregular spheres with a rough surface under a scanning electron microscope and a narrow size distribution ranging from 20 to 700 μm. The transmission electron microscopy images showed that the structure of microcapsules containing Lactobacillus reuteri (L. reuteri) was a core and shell structure. The survival of L. reuteri in microcapsules was significantly more than that of free L. reuteri in the simulated stomach environment of pH 1.2. 16S rDNA sequencing showed that LMCs observably increased the relative abundance of Lactobacillus in RIBI mice. More importantly, compared with the RIBI model mice, the behavior of RIBI mice treated with LMCs was significantly improved. In addition, LMCs greatly alleviated the pathological damage of the hippocampus and intestines in the mice after irradiation and reduced the level of TNF-α and IL-6 in vivo. Generally, LMCs are a promising oral preparation, which provide new ideas and methods for the treatment of RIBI.

Microbiota-Accessible Boron-Containing Compounds in Complex Regional Pain Syndrome

The microbiota-gut-brain axis has garnered increasing attention in recent years for its role in various health conditions, including neuroinflammatory disorders like complex regional pain syndrome (CRPS). CRPS is a debilitating condition characterized by chronic neuropathic pain, and its etiology and pathophysiology remain elusive. Emerging research suggests that alterations in the gut microbiota composition and function could play a significant role in CRPS development and progression. Our paper explores the implications of microbiota in CRPS and the potential therapeutic role of boron (B). Studies have demonstrated that individuals with CRPS often exhibit dysbiosis, with imbalances in beneficial and pathogenic gut bacteria. Dysbiosis can lead to increased gut permeability and systemic inflammation, contributing to the chronic pain experienced in CRPS. B, an essential trace element, has shown promise in modulating the gut microbiome positively and exerting anti-inflammatory effects. Recent preclinical and clinical studies suggest that B supplementation may alleviate neuropathic pain and improve CRPS symptoms by restoring microbiota balance and reducing inflammation. Our review highlights the complex interplay between microbiota, inflammation, and neuropathic pain in CRPS and underscores the potential of B as a novel therapeutic approach to target the microbiota-gut-brain axis, offering hope for improved management of this challenging condition.

Maternal autoimmune disease and risk of offspring autism spectrum disorder - a nationwide population-based cohort study

Introduction

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders which cause long term social and behavior impairment, and its prevalence is on the rise. Studies about the association between maternal autoimmune diseases and offspring ASD have controversial results. The aim of this study was to investigate whether maternal autoimmune diseases increase the risk of ASD in offspring from a population-based perspective.

Methods

The data sources were Taiwan's National Health Insurance Research Database (NHIRD) and Taiwan's Maternal and Child Health Database (MCHD), which were integrated and used to identify newborns whose mothers were diagnosed with autoimmune disease. Newborns were matched by maternal age, neonatal gender, and date of birth with controls whose mothers were without autoimmune disease using a ratio of 1:4 between 2004 and 2019. Data on diagnoses of autoimmune disease and autism spectrum disorders were retrieved from NHIRD. Patients who had at least 3 outpatient visits or at least 1 admission with a diagnosis of autoimmune disease and autism spectrum disorders were defined as incidence cases. The risks of ASD in offspring were compared between mothers with or without autoimmune disorders.

Results

We identified 20,865 newborns whose mothers had been diagnosed with autoimmune disease before pregnancy and matched them at a ratio of 1:4 with a total of 83,460 newborn whose mothers were without autoimmune disease, by maternal age, neonatal gender, and date of birth. They were randomly selected as the control group. The cumulative incidence rates of autism spectrum disorders (ASD) were significantly higher among the offspring of mothers with autoimmune diseases. After adjusting for cofactors, the risk of ASD remained significantly higher in children whose mother had autoimmune diseases. Regarding to specific maternal autoimmune disease, Sjögren's syndrome and rheumatoid arthritis were both associated with elevated risks of ASD in offspring.

Conclusion

Mother with autoimmune disease might be associated with increasing the risk of autism spectrum disorder in offspring.

Brain-inhabiting bacteria and neurodegenerative diseases: the "brain microbiome" theory

Controversies surrounding the validity of the toxic proteinopathy theory of Alzheimer's disease have led the scientific community to seek alternative theories in the pathogenesis of neurodegenerative disorders (ND). Recent studies have provided evidence of a microbiome in the central nervous system. Some have hypothesized that brain-inhabiting organisms induce chronic neuroinflammation, leading to the development of a spectrum of NDs. Bacteria such as Chlamydia pneumoniae, Helicobacter pylori, and Cutibacterium acnes have been found to inhabit the brains of ND patients. Furthermore, several fungi, including Candida and Malassezia species, have been identified in the central nervous system of these patients. However, there remains several limitations to the brain microbiome hypothesis. Varying results across the literature, concerns regarding sample contamination, and the presence of exogenous deoxyribonucleic acids have led to doubts about the hypothesis. These results provide valuable insight into the pathogenesis of NDs. Herein, we provide a review of the evidence for and against the brain microbiome theory and describe the difficulties facing the hypothesis. Additionally, we define possible mechanisms of bacterial invasion of the brain and organism-related neurodegeneration in NDs and the potential therapeutic premises of this theory.

Characterization of gut microbiota profile in Iranian patients with bipolar disorder compared to healthy controls

Introduction

The human gut microbiota plays a crucial role in mental health through the gut-brain axis, impacting central nervous system functions, behavior, mood, and anxiety. Consequently, it is implicated in the development of neuropsychiatric disorders. This study aimed to assess and compare the gut microbiota profiles and populations of individuals with bipolar disorder and healthy individuals in Iran.

Methods

Fecal samples were collected from 60 participants, including 30 bipolar patients (BPs) and 30 healthy controls (HCs), following rigorous entry criteria. Real-time quantitative PCR was utilized to evaluate the abundance of 10 bacterial genera/species and five bacterial phyla.

Results

Notably, Actinobacteria and Lactobacillus exhibited the greatest fold change in BPs compared to HCs at the phylum and genus level, respectively, among the bacteria with significant population differences. Ruminococcus emerged as the most abundant genus in both groups, while Proteobacteria and Bacteroidetes showed the highest abundance in BPs and HCs, respectively, at the phylum level. Importantly, our investigation revealed a lower Firmicutes/Bacteroidetes ratio, potentially serving as a health indicator, in HCs compared to BPs.

Conclusion

This study marks the first examination of an Iranian population and provides compelling evidence of significant differences in gut microbiota composition between BPs and HCs, suggesting a potential link between brain functions and the gut microbial profile and population.

The synergistic mechanism of action of Dajianzhong decoction in conjunction with ketamine in the treatment of depression

Depression is a multifactorial syndrome with a variety of underlying pathological mechanisms. While ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, exhibits a rapid antidepressant action in the central never system (CNS), the potential addiction and psychotomimetic adverse effects of ketamine limit its chronic use in clinical practice. Therefore, it is necessary to discover an additional agent that shows a synergistic antidepressant activity with ketamine to sustain its therapeutic action so as to reduce its use frequency in depression treatment. The present study indicated that Dajianzhong decoction (DJZT), an empirical herbal formula used for the clinical treatment of several inflammation-related intestinal disorders, sustains behavioral and synaptic action of ketamine in depressive mouse models. Additionally, ketamine was also demonstrated to exert a synergistic action with DJZT to alleviate the chronic unpredictable mild stress (CUMS)-induced abnormalities in gut barrier proteins and colonic histology, and subsequently to normalize the diversity and composition of gut microbiota. Furthermore, DJZT was shown to possess an anti-inflammatory activity to prevent activation of NF-κB from releasing proinflammatory cytokines, specifically through inhibiting Th17 cells/IL-17A pathway. Our results uncovered the mechanism of action of DJZT in conjunction with ketamine in depression treatment by which these agents target different pathological factors across biological systems and exert a synergistic activity through a bidirectional communication in the gut-brain axis, and also provided new insights into the systematic treatment of depression.

Emerging role of the host microbiome in neuropsychiatric disorders: overview and future directions

The human body harbors a diverse ecosystem of microorganisms, including bacteria, viruses, and fungi, collectively known as the microbiota. Current research is increasingly focusing on the potential association between the microbiota and various neuropsychiatric disorders. The microbiota resides in various parts of the body, such as the oral cavity, nasal passages, lungs, gut, skin, bladder, and vagina. The gut microbiota in the gastrointestinal tract has received particular attention due to its high abundance and its potential role in psychiatric and neurodegenerative disorders. However, the microbiota presents in other body tissues, though less abundant, also plays crucial role in immune system and human homeostasis, thus influencing the development and progression of neuropsychiatric disorders. For example, oral microbiota imbalance and associated periodontitis might increase the risk for neuropsychiatric disorders. Additionally, studies using the postmortem brain samples have detected the widespread presence of oral bacteria in the brains of patients with Alzheimer's disease. This article provides an overview of the emerging role of the host microbiota in neuropsychiatric disorders and discusses future directions, such as underlying biological mechanisms, reliable biomarkers associated with the host microbiota, and microbiota-targeted interventions, for research in this field.

Gut Microbiome Dysbiosis as a Potential Risk Factor for Idiopathic Toe-Walking in Children: A Review

Idiopathic toe walking (ITW) occurs in about 5% of children. Orthopedic treatment of ITW is complicated by the lack of a known etiology. Only half of the conservative and surgical methods of treatment give a stable positive result of normalizing gait. Available data indicate that the disease is heterogeneous and multifactorial. Recently, some children with ITW have been found to have genetic variants of mutations that can lead to the development of toe walking. At the same time, some children show sensorimotor impairment, but these studies are very limited. Sensorimotor dysfunction could potentially arise from an imbalanced production of neurotransmitters that play a crucial role in motor control. Using the data obtained in the studies of several pathologies manifested by the association of sensory-motor dysfunction and intestinal dysbiosis, we attempt to substantiate the notion that malfunction of neurotransmitter production is caused by the imbalance of gut microbiota metabolites as a result of dysbiosis. This review delves into the exciting possibility of a connection between variations in the microbiome and ITW. The purpose of this review is to establish a strong theoretical foundation and highlight the benefits of further exploring the possible connection between alterations in the microbiome and TW for further studies of ITW etiology.

Depression and lifestyle: Focusing on nutrition, exercise, and their possible relevance to molecular mechanisms

Accumulating evidence has suggested the important role of lifestyle factors in depressive disorder. This paper aimed to introduce and outline recent research on epidemiological and intervention studies on lifestyle-related factors in depressive disorder with a special focus on diet. Evidence on exercise, sleep. and related behaviors is also described. Here, findings from meta-analytic studies are emphasized and related studies by the author's research group are introduced. Dietary factors that increase the risk of the illness include energy overload, skipping breakfast, unhealthy diet styles such as Western diet, inflammation-prone diet, and high consumption of ultraprocessed food (UPF). Nutritional imbalances such as inadequate intake of protein, fish (Ω3 polyunsaturated fatty acids), vitamins (folate and vitamin D), and minerals (iron and zinc) increases the risk of depression. Poor oral hygiene, food allergy, addiction to alcohol, and smoking constitute risk factors. Sedentary lifestyle and increased screen time (e.g. video games and the internet) confer the risk of depression. Insomnia and disturbed sleep-wake rhythm are also involved in the pathogenesis of depression. There is accumulating evidence at the meta-analysis level for interventions to modify these lifestyle habits in the protection and treatment of depressive disorder. Main biological mechanisms of the link between lifestyle factors and depression include monoamine imbalance, inflammation, altered stress response, oxidative stress, and dysfunction of brain-derived neurotrophic factor, although other players such as insulin, leptin, and orexin also play a role. To increase resilience to modern stress and ameliorate depression through modification of lifestyle habits, a list of 30 recommendable interventions is presented.

Epigenetic Aberrations in Major Psychiatric Diseases Related to Diet and Gut Microbiome Alterations

Nutrition and metabolism modify epigenetic signatures like histone acetylation and DNA methylation. Histone acetylation and DNA methylation in the central nervous system (CNS) can be altered by bioactive nutrients and gut microbiome via the gut-brain axis, which in turn modulate neuronal activity and behavior. Notably, the gut microbiome, with more than 1000 bacterial species, collectively contains almost three million functional genes whose products interact with millions of human epigenetic marks and 30,000 genes in a dynamic manner. However, genetic makeup shapes gut microbiome composition, food/nutrient metabolism, and epigenetic landscape, as well. Here, we first discuss the effect of changes in the microbial structure and composition in shaping specific epigenetic alterations in the brain and their role in the onset and progression of major mental disorders. Afterward, potential interactions among maternal diet/environmental factors, nutrition, and gastrointestinal microbiome, and their roles in accelerating or delaying the onset of severe mental illnesses via epigenetic changes will be discussed. We also provide an overview of the association between the gut microbiome, oxidative stress, and inflammation through epigenetic mechanisms. Finally, we present some underlying mechanisms involved in mediating the influence of the gut microbiome and probiotics on mental health via epigenetic modifications.

Functional Foods: A Promising Strategy for Restoring Gut Microbiota Diversity Impacted by SARS-CoV-2 Variants

Natural herbs and functional foods contain bioactive molecules capable of augmenting the immune system and mediating anti-viral functions. Functional foods, such as prebiotics, probiotics, and dietary fibers, have been shown to have positive effects on gut microbiota diversity and immune function. The use of functional foods has been linked to enhanced immunity, regeneration, improved cognitive function, maintenance of gut microbiota, and significant improvement in overall health. The gut microbiota plays a critical role in maintaining overall health and immune function, and disruptions to its balance have been linked to various health problems. SARS-CoV-2 infection has been shown to affect gut microbiota diversity, and the emergence of variants poses new challenges to combat the virus. SARS-CoV-2 recognizes and infects human cells through ACE2 receptors prevalent in lung and gut epithelial cells. Humans are prone to SARS-CoV-2 infection because their respiratory and gastrointestinal tracts are rich in microbial diversity and contain high levels of ACE2 and TMPRSS2. This review article explores the potential use of functional foods in mitigating the impact of SARS-CoV-2 variants on gut microbiota diversity, and the potential use of functional foods as a strategy to combat these effects.

The Brain-Gut-Microbiota Interplay in Depression: a key to design innovative therapeutic approaches

Depression is the most prevalent mental disorder in the world associated with huge socio-economic consequences. While depressive-related symptoms are well known, the molecular mechanisms underlying disease pathophysiology and progression remain largely unknown. The gut microbiota (GM) is emerging as a key regulator of the central nervous system homeostasis by exerting fundamental immune and metabolic functions. In turn, the brain influences the intestinal microbial composition through neuroendocrine signals, within the so-called gut microbiota-brain axis. The balance of this bidirectional crosstalk is important to ensure neurogenesis, preserve the integrity of the blood-brain barrier and avoid neuroinflammation. Conversely, dysbiosis and gut permeability negatively affect brain development, behavior, and cognition. Furthermore, although not fully defined yet, changes in the GM composition in depressed patients are reported to influence the pharmacokinetics of common antidepressants by affecting their absorption, metabolism, and activity. Similarly, neuropsychiatric drugs may shape in turn the GM with an impact on the efficacy and toxicity of the pharmacological intervention itself. Consequently, strategies aimed at re-establishing the correct homeostatic gut balance (i.e., prebiotics, probiotics, fecal microbiota transplantation, and dietary interventions) represent an innovative approach to improve the pharmacotherapy of depression. Among these, probiotics and the Mediterranean diet, alone or in combination with the standard of care, hold promise for clinical application. Therefore, the disclosure of the intricate network between GM and depression will give precious insights for innovative diagnostic and therapeutic approaches towards depression, with profound implications for drug development and clinical practice.

Probiotics and Commensal Bacteria Metabolites Trigger Epigenetic Changes in the Gut and Influence Beneficial Mood Dispositions

The effect of the intestinal microbiome on the gut-brain axis has received considerable attention, strengthening the evidence that intestinal bacteria influence emotions and behavior. The colonic microbiome is important to health and the pattern of composition and concentration varies extensively in complexity from birth to adulthood. That is, host genetics and environmental factors are complicit in shaping the development of the intestinal microbiome to achieve immunological tolerance and metabolic homeostasis from birth. Given that the intestinal microbiome perseveres to maintain gut homeostasis throughout the life cycle, epigenetic actions may determine the effect on the gut-brain axis and the beneficial outcomes on mood. Probiotics are postulated to exhibit a range of positive health benefits including immunomodulating capabilities. Lactobacillus and Bifidobacterium are genera of bacteria found in the intestines and so far, the benefits afforded by ingesting bacteria such as these as probiotics to people with mood disorders have varied in efficacy. Most likely, the efficacy of probiotic bacteria at improving mood has a multifactorial dependency, relying namely on several factors that include the agents used, the dose, the pattern of dosing, the pharmacotherapy used, the characteristics of the host and the underlying luminal microbial environment (e.g., gut dysbiosis). Clarifying the pathways linking probiotics with improvements in mood may help identify the factors that efficacy is dependent upon. Adjunctive therapies with probiotics for mood disorders could, through DNA methylation molecular mechanisms, augment the intestinal microbial active cohort and endow its mammalian host with important and critical co-evolutionary redox signaling metabolic interactions, that are embedded in bacterial genomes, and that in turn can enhance beneficial mood dispositions.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

Repeated use of 3,4-methylenedioxymethamphetamine is associated with the resilience in mice after chronic social defeat stress: A role of gut-microbiota-brain axis

3,4-Methylenedioxymethamphetamine (MDMA), the most widely used illicit compound worldwide, is the most attractive therapeutic drug for post-traumatic stress disorder (PTSD). Recent observational studies of US adults demonstrated that lifetime MDMA use was associated with lower risk of depression. Here, we examined whether repeated administration of MDMA can affect resilience versus susceptibility in mice exposed to chronic social defeat stress (CSDS). CSDS produced splenomegaly, anhedonia-like phenotype, and higher plasma levels of interleukin-6 (IL-6) in the saline-treated mice. In contrast, CSDS did not cause these changes in the MDMA-treated mice. Analysis of gut microbiome found several microbes altered between saline + CSDS group and MDMA + CSDS group. Untargeted metabolomics analysis showed that plasma levels of N-epsilon-methyl-L-lysine in the saline + CSDS group were significantly higher than those in the control and MDMA + CSDS groups. Interestingly, there were positive correlations between plasma IL-6 levels and the abundance of several microbes (or plasma N-epsilon-methyl-L-lysine) in the three groups. Furthermore, there were also positive correlations between the abundance of several microbes and N-epsilon-methyl-L-lysine in the three groups. In conclusion, these data suggest that repeated administration of MDMA might contribute to stress resilience in mice subjected to CSDS through gut-microbiota-brain axis.

Exposure to Antibiotics and Neurodevelopmental Disorders: Could Probiotics Modulate the Gut-Brain Axis?

In order to develop properly, the brain requires the intricate interconnection of genetic factors and pre-and postnatal environmental events. The gut-brain axis has recently raised considerable interest for its involvement in regulating the development and functioning of the brain. Consequently, alterations in the gut microbiota composition, due to antibiotic administration, could favor the onset of neurodevelopmental disorders. Literature data suggest that the modulation of gut microbiota is often altered in individuals affected by neurodevelopmental disorders. It has been shown in animal studies that metabolites released by an imbalanced gut-brain axis, leads to alterations in brain function and deficits in social behavior. Here, we report the potential effects of antibiotic administration, before and after birth, in relation to the risk of developing neurodevelopmental disorders. We also review the potential role of probiotics in treating gastrointestinal disorders associated with gut dysbiosis after antibiotic administration, and their possible effect in ameliorating neurodevelopmental disorder symptoms.