Human Gut Microbiota from Autism Spectrum Disorder Promote Behavioral Symptoms in Mice

Maternal-infant probiotic transmission mitigates early-life stress-induced autism in mice

Autism, a disorder influenced by both genetic and environmental factors, presents significant challenges for prevention and treatment. While maternal-infant gut microbiota has been a focus in autism research, preventive strategies targeting maternal gut microbiota remain underexplored. This study demonstrates that prenatal probiotic intake can effectively prevent maternal separation-induced autistic-like behaviors in offspring without altering the embryonic neurodevelopment in mice. Using specific PCR primers and cross-fostering experiments, we traced the vertical transmission of probiotics, primarily via fecal/vaginal contamination. Early probiotic colonization conferred resilience against stress-induced gut pathogenic microbes and Th17-mediated peripheral inflammation while significantly inhibiting hypermyelination and neuroinflammation linked to systemic inflammation. Microbial metabolites like tyrosol and xanthurenic acid alleviated neuroinflammation and hypermyelination in vitro, though the causal relationship among neuroinflammation, hypermyelination, and autism in vivo requires further validation. These findings underscore the importance of the maternal-infant microbiota transmission window in autism prevention and highlight the clinical potential of prenatal probiotic interventions.

Mouse strain-specific responses along the gut-brain axis upon fecal microbiota transplantation from children with autism

Several factors are linked to the pathophysiology of autism spectrum disorders (ASD); however, the molecular mechanisms of the condition remain unknown. As intestinal problems and gut microbiota dysbiosis are associated with ASD development and severity, recent studies have focused on elucidating the microbiota-gut-brain axis' involvement. This study aims to explore mechanisms through which gut microbiota might influence ASD. Briefly, we depleted the microbiota of conventional male BALB/cAnNCrl (Balb/c) and C57BL/6J (BL/6) mice prior to human fecal microbiota transplantation (hFMT) with samples from children with ASD or their neurotypical siblings. We found mouse strain-specific responses to ASD hFMT. Notably, Balb/c mice exhibit decreased exploratory and social behavior, and show evidence of intestinal, systemic, and central inflammation accompanied with metabolic shifts. BL/6 mice show less changes after hFMT. Our results reveal that gut microbiota alone induce changes in ASD-like behavior, and highlight the importance of mouse strain selection when investigating multifactorial conditions like ASD.

Data independent acquisition proteomics and machine learning reveals that proteins associated with immunity are potential molecular markers for early diagnosis of autism

BACKGROUND

Early diagnosis of autism is critical to its treatment, but so far, there is no clear molecular marker for early diagnosis in children.

METHODS

We used data independent acquisition (DIA) mass spectrometry to compare protein expression in serum from 99 Chinese children with autism spectrum disorders with 70 healthy children.

RESULTS

We identified 347 downregulated and 394 upregulated proteins. Based on bioinformatics analysis, differential proteins were enriched in the immune system, immune disease, cell motility, and focal adhesion. Machine learning revealed a model with eight proteins (IGH c1898_heavy_IGHV3-33_IGHD3-9_IGHJ4, LYZ, IGL c1860_light_IGLV8-61_IGLJ2, SERPINA10, IG c1421_light_IGKV1-27_IGKJ4, rheumatoid factor RF-ET1, IGL c600_light_IGKV4-1_IGKJ4, and SELL) that were mostly associated with immunity, and accurate for diagnosis of autism. The protein family was verified by a logic-regression leave-one cross-validation method with bidirectional feature screening. The accuracy of this model was 0.9527, and the kappa coefficient was 0.9025.

CONCLUSIONS

Our study showed that immunity is closely related to the onset of autism and can be used for early screening of patients. A model with eight proteins (IGH c1898_heavy_IGHV3-33_IGHD3-9_IGHJ4, LYZ, IGL c1860_light_IGLV8-61_IGLJ2, SERPINA10, IG c1421_light_IGKV1-27_IGKJ4, rheumatoid factor RF-ET1, IGL c600_light_IGKV4-1_IGKJ4, and SELL), which are mostly associated with immunity, is accurate for diagnosis of autism.

Do gastrointestinal symptoms influence neurocognitive functioning in COVID-19 patients?

BACKGROUND AND OBJECTIVES

SARS-Cov-19 virus is known to attack multiple organ systems including the brain and as a result, numerous of these patients manifest neurocognitive disorders. Moreover COVID-19, causes gastrointestinal symptoms such as nausea and vomiting, abdominal pain, diarrhea or constipation, loss of appetite and weight loss and these symptoms have been linked to neurocognitive dysfunction. According to studies, COVID-19 patients who report gastrointestinal symptoms as the predominant manifestations, perform worse on neurocognitive tests than those who do not suffer from such symptoms. In this study, we examined whether hospitalized COVID-19 patients with gastrointestinal symptoms presented neurocognitive dysfunction.

MATERIALS AND METHODS

The study enrolled 92 COVID-19 patients, hospitalized for 6-20 days, who were divided into 2 groups: the gastrointestinal group (GI) (n = 44) who presented with predominant gastrointestinal symptoms such as anorexia, nausea, vomiting, diarrhea and abdominal pain and the group without GI symptoms, (nGI) (n = 48), who reported fever, fatigue and symptoms from the respiratory system as the main symptoms. Neurocognitive assessment was performed by questionnaires administered to all patients, three months after the first positive PCR test for COVID-19.

RESULTS

T-test was conducted for each test. Results revealed that patients with GI symptoms had significantly lower performance on neuropsychological functions such as complex scanning and long-term memory, visuospatial perception, executive function, verbal working memory and short-term memory, compared to patients without GI symptoms.

CONCLUSIONS

We found that there was a significant relationship between cognitive function and GI symptoms. This indicates that COVID-19 patients with GI symptoms may be at increased risk for developing deficits with their memory and other aspects of cognition.

Differences in anti-obesity effects between raw and ripened Pu-erh tea polyphenols: impact on gut microbiota enterotypes

BACKGROUND

Pu-erh tea, a dark tea from China, is classified into raw and ripened types. Both have significant anti-obesity effects. Polyphenols are among their major bioactive components. This study aimed to explore the anti-obesity properties and mechanisms of raw (R-TP) and ripened (F-TP) Pu-erh tea polyphenols.

RESULTS

The results showed that R-TP and F-TP significantly reduced body weight, improved insulin resistance, and enhanced glucose and lipid metabolism in high-fat-diet (HFD)-induced obese mice. Mild differences were observed in their impact on fat metabolism, carbohydrate metabolism, and inflammation levels. Both R-TP and F-TP were able to restore the disrupted intestinal flora caused by HFD treatment, returning them to a composition and levels similar to those of normal mice. Interestingly, the gut microbiota of all the mice could be reclassified into three enterotypes (enterotype Type-1, Type-2, and Type-HFD). Lactobacillaceae predominated in Type-1. Lactobacillaceae, Muribaculaceae, and Lachnospiraceae were the most common in Type-2. Type-HFD was primarily composed of Atopobiaceae, Lachnospiraceae, Lactobacillaceae, Ruminococcaceae, and Erysipelotrichaceae. The small differences in the effects of R-TP and F-TP may be due to variations in enterotypes.

CONCLUSION

These findings indicate that R-TP and F-TP can alleviate obesity by regulating the enterotype of gut microbiota, suggesting that they possess the potential for application in the treatment of obesity and the development of anti-obesity agents. © 2025 Society of Chemical Industry.

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.

Comprehensive Management of Ulcerative Colitis and its Associated Intra-Extra Intestinal Complications with a Multifunctional Inulin Hydrogel Complex

Excessive accumulation of reactive oxygen species (ROS) and dysbiosis of gut microbiota are pivotal etiological factors in the pathogenesis of ulcerative colitis (UC) and its associated intestinal and extraintestinal manifestations (e.g., intestinal microthrombosis, anxiety, and depression symptoms). This investigation presents a multifunctional inulin complex (PB/NKase@Inulin gel) incorporating Prussian blue nanozymes (PB NZs) and the thrombolytic agent nattokinase (NKase) for the therapeutic management of dextran sulfate sodium (DSS)-induced UC and its associated intestinal and extraintestinal complications. Following oral administration, the PB/NKase@Inulin gel, characterized by prolonged retention of PB NZs and NKase at inflamed colonic sites, can facilitate continuously ROS scavenging, attenuate oxidative stress damage, effectively reduce pro-inflammatory cytokine levels. Importantly, PB/NKase@Inulin gel can not only robustly inhibit inflammatory microthrombosis formation but also effectively lyses thrombi due to the potent thrombolytic properties of NKase both in vitro and in vivo. Furthermore, the PB/NKase@Inulin gel is able to modulate gut microbiota homeostasis and alleviate multiple stresses responses (including anxiety and depression) in a UC mouse model via microbiota-gut-brain (MGB) axis interactions. Overall, the PB/NKase@Inulin gel offers an innovative paradigm for comprehensive therapeutic interventions in DSS-induced UC and its multifaceted complications.

Limitations of genomics to predict and treat autism: a disorder born in the womb

Brain development involves the sequential expression of vulnerable biological processes including cell proliferation, programmed cell death, neuronal migration, synapse and functional unit formation. All these processes involve gene and activity-dependent events that can be distorted by many extrinsic and intrinsic environmental factors, including stress, microbiota, inflammatory signals, hormonal signals and epigenetic factors, hence leading to disorders born in the womb that are manifested later in autism spectrum disorders (ASDs) and other neurodevelopmental disorders. Predicting and treating such disorders call for a conceptual framework that includes all aspects of developmental biology. Here, taking the high incidence of ASDs as an example, we first discuss the intrinsic limitations of the genetic approach, notably the widely used twin studies and SNPs. We then review the long list of in utero events that can deviate developmental sequences, leading to persistent aberrant activity generated by immature misplaced and misconnected neuronal ensembles that are the direct cause of ASD. In a clinical perspective, we suggest analysing non-genetic maternity data to enable an early prediction of babies who will develop ASD years later, thereby facilitating early psycho-educative techniques. Subsequently, agents capable of selectively silencing malformed immature networks offer promising therapeutic perspectives. In summary, understanding developmental processes is critical to predicting, understanding and treating ASD, as well as most other disorders that arise in the womb.

Nitrate ameliorates alcohol-induced cognitive impairment via oral microbiota

Alcohol use is associated with cognitive impairment and dysregulated inflammation. Oral nitrate may benefit cognitive impairment in aging through altering the oral microbiota. Similarly, the beneficial effects of nitrate on alcohol-induced cognitive decline and the roles of the oral microbiota merit investigation. Here we found that nitrate supplementation effectively mitigated cognitive impairment induced by chronic alcohol exposure in mice, reducing both systemic and neuroinflammation. Furthermore, nitrate restored the dysbiosis of the oral microbiota caused by alcohol consumption. Notably, removing the oral microbiota led to a subsequent loss of the beneficial effects of nitrate. Oral microbiota from donor alcohol use disordered humans who had been taking the nitrate intervention were transplanted into germ-free mice which then showed increased cognitive function and reduced neuroinflammation. Finally, we examined 63 alcohol drinkers with varying levels of cognitive impairment and found that lower concentrations of nitrate metabolism-related bacteria were associated with higher cognitive impairment and lower nitrate levels in plasma. These findings highlight the protective role of nitrate against alcohol-induced cognition impairment and neuroinflammation and suggest that the oral microbiota associated with nitrate metabolism and brain function may form part of a "microbiota-mouth-brain axis".

Perinatal exposure to the autism-linked metabolite p-Cresol has limited impact on early development in mice but lasting effects on adult social behavior

Environmental exposures during pregnancy are increasingly recognized as significant risk factors for the offspring health. Perinatal exposure to environmental toxins, including p-Cresol, may disrupt essential physiological processes during critical developmental windows. The perinatal period is particularly critical for neurodevelopment, making the brain particularly vulnerable to external toxins that can impair neural circuitry and increase the risk of behavioral and neuropsychiatric disorders later in life. p-Cresol, a microbial metabolite produced by the human microbiota and through the bacterial decomposition of organic matter, is also released in exhaust fumes and widely used in chemical manufacturing. Elevated levels of p-Cresol have been consistently observed in patients with autism spectrum disorders (ASD), yet, its developmental toxicity and its impact on ASD-related behaviors remain to be determined. In this study, we exposed pregnant mice (C57BL/6J) to p-Cresol via drinking water from mid-gestation, through lactation, and until weaning, mimicking potential patterns of human exposure during pregnancy and early infancy. Our findings indicated that while perinatal p-Cresol exposure did not affect gestational outcomes, postnatal growth, developmental milestones, or sensorimotor reflexes, it resulted in marked social deficits and stereotyped behaviors in adult males and females offspring-which are core behavioral phenotypes associated with ASD. These results suggest that p-Cresol exposure selectively induces ASD-like behaviors, without broadly impairing early development. Our findings emphasize the need for future epidemiological studies to quantify p-Cresol exposure during pregnancy and early childhood, and to evaluate its potential association with social behavior impairments in children. This research provides a foundation for understanding how environmental factors, such as p-Cresol, may contribute to social impairments and neurodevelopmental disorders in the broader population.

Relationships between brain activity, tryptophan-related gut metabolites, and autism symptomatology

While it has been suggested that alterations in the composition of gut microbial metabolites may play a causative role in the pathophysiology of autism spectrum disorder (ASD), it is not known how gut microbial metabolites are associated with ASD-specific brain alterations. In this cross-sectional, case-control observational study, (i) fecal metabolomics, (ii) task-based functional magnetic resonance imaging (fMRI), and (iii) behavioral assessments were obtained from 43 ASD and 41 neurotypical (NT) children, aged 8-17. The fMRI tasks used socio-emotional and sensory paradigms that commonly reveal strong evoked brain differences in ASD participants. Our results show that fecal levels of specific tryptophan-related metabolites, including kynurenate, were significantly lower in ASD compared to NT, and were associated with: 1) alterations in insular and cingulate cortical activity previously implicated in ASD; and 2) ASD severity and symptoms (e.g., ADOS scores, disgust propensity, and sensory sensitivities). Moreover, activity in the mid-insula and mid-cingulate significantly mediated relationships between the microbial tryptophan metabolites (indolelactate and tryptophan betaine) and ASD severity and disgust sensitivity. Thus, we identify associations between gut microbial tryptophan metabolites, ASD symptoms, and brain activity in humans, particularly in brain regions associated with interoceptive processing.

Comparative analyses of the gut microbiome of two sympatric rodent species, Myodes rufocanus and Apodemus peninsulae, in northeast China based on metagenome sequencing

The gut microbiota is integral to an animal's physiology, influencing nutritional metabolism, immune function, and environmental adaptation. Despite the significance of gut microbiota in wild rodents, the Korean field mouse (Apodemus peninsulae) and the gray red-backed vole (Myodes rufocanus) remain understudied. To address this, a metagenomic sequencing analysis of the gut microbiome of these sympatric rodents in northeast China's temperate forests was conducted. Intestinal contents were collected from A. peninsulae and M. rufocanus within the Mudanfeng National Nature Reserve. High-throughput sequencing elucidated the gut microbiome's composition, diversity, and functional pathways. Firmicutes, Bacteroidetes, and Proteobacteria were identified as the dominant phyla, with M. rufocanus showing greater microbiome diversity. Key findings indicated distinct gut bacterial communities between the species, with M. rufocanus having a higher abundance of Proteobacteria. The gut microbiota of A. peninsulae and M. rufocanus differed marginally in functional profiles, specifically in the breakdown of complex carbohydrates, which might reflect their distinct food preferences albeit both being herbivores with a substantial dietary overlap. The investigation further elucidated gut microbiota's contributions to energy metabolism and environmental adaptation mechanisms. This study aligns with information on rodent gut microbiota in literature and highlights the two understudied rodent species, providing comparative data for future studies investigating the role of gut microbiota in wildlife health and ecosystem functioning.

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.

Gut microbiome differences in children with Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder and effects of probiotic supplementation: A randomized controlled trial

BACKGROUND

Emerging evidence suggests a significant role of gut microbiota on neurodevelopmental disorders, including Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD).

AIMS

Our study aimed to compare gut microbiota composition between these disorders and evaluate the effect of probiotic supplementation.

METHODS

We conducted a 12-week randomized, double-blind, placebo-controlled trial with 80 children aged 5-14 years (39 with ADHD, 41 with ASD). Baseline and post-intervention fecal samples were analyzed using 16S rRNA gene sequencing to identify changes in gut microbiota composition.

RESULTS

We identified 22 taxa differentiating ADHD and ASD (AUC = 0.939), characterised by increased presence of Clostridia, Ruminococcaceae, and Lachnospiraceae in ADHD, and Bacteroides, Bacilli and Actinobacteria in ASD. These differences remained after accounting for potential confounders. ASD children receiving probiotics had significant increases in Chao 1, Fisher's alpha, and Shannon indices whereas no significant differences in α and β-diversity were found in ADHD. In ADHD, bacteria with potential adverse effects were under-represented. In ASD, the abundance of Eggerthellaceae, and other taxa associated with gastrointestinal problems and anxiety was decreased.

CONCLUSION

Variations in gut microbiota may influence responses in ADHD and ASD. Probiotic supplementation favorably altered gut microbiota composition, offering insights for future therapeutic strategies targeting the microbiome in neurodevelopmental disorders.

WHAT THIS PAPER ADDS

Recent research underscores the role of gut microbiota in ADHD and ASD, indicating that diet can significantly influence microbiota composition and potentially manage these neurodevelopmental disorders. This study reveals distinct differences in gut microbiota composition between children with ADHD and ASD and demonstrates that probiotic supplementation can modulate specific microbial genera in each disorder. These findings pave the way for the development of innovative microbiome-targeted therapies, offering a new avenue for the treatment of neurodevelopmental disorders. Understanding this relationship is crucial for designing future interventions.

Influence of gut microbiota on the pediatric endocrine system and associated disorders

The microbiota, a complex assembly of microorganisms residing in various body systems, including the gastrointestinal tract, plays a crucial role in influencing various physiological processes in the human body. The dynamic nature of gut microbiota is especially pronounced in children and is influenced by factors like breastfeeding and antibiotic use. Dysbiosis, characterized by alterations in microbiota composition or function, is associated with several pediatric endocrine disorders, such as precocious puberty, polycystic ovarian syndrome, and diabetes mellitus. This review focuses on the intricate relationship between gut microbiota and the pediatric endocrine system. The aim of this narrative review is to critically examine the existing literature to elucidate the impact of gut microbiota on the pediatric endocrine system and associated disorders. Additionally, potential interventions, such as probiotics and current gaps in knowledge, will be discussed. Despite emerging treatments like probiotics, further research is needed to understand and validate their effectiveness in treating pediatric endocrine disorders associated with dysbiosis.

Little Peacemakers: Microbes Can Promote Nonviolent Conflict Resolution by Their Hosts

Conflicts between individuals of the same species are common in nature and are mostly resolved with limited aggression. Several theoretical studies, such as the Hawk-Dove (HD) game model, investigate the evolution of limited aggression expressed during conflicts between individuals. These studies mainly focus on the individuals involved in the conflict and their genes. Recently accumulating evidence indicates that microbes are associated with diverse functions of their host and can affect host behavior. Here we extend the classic HD game model to include both the hosts and their microbes, examining how natural selection acts on the microbes. We find that nonaggressive host behavior is more likely to evolve and spread in a population when induced by the microbes residing in the host, compared to nonaggressive behavior induced by host genes. Horizontal transmission allows microbes to colonize new hosts, making their success dependent on the fitness of both the host and its opponent. Therefore, selection on the microbes favors reduced host aggressiveness under wider conditions compared to selection acting on genes alone. Our results suggest that microbes may help explain the ubiquity of nonviolent conflict resolution. Consequently, factors that alter the microbial composition within hosts may affect the aggressiveness level in host populations.

Fecal microbiota transplantation: transitioning from chaos and controversial realm to scientific precision era

With the popularization of modern lifestyles, the spectrum of intestinal diseases has become increasingly diverse, presenting significant challenges in its management. Traditional pharmaceutical interventions have struggled to keep pace with these changes, leaving many patients refractory to conventional pharmaceutical treatments. Fecal microbiota transplantation (FMT) has emerged as a promising therapeutic approach for enterogenic diseases. Still, controversies persist regarding its active constituents, mechanism of action, scheme of treatment evaluation, indications, and contraindications. In this review, we investigated the efficacy of FMT in addressing gastrointestinal and extraintestinal conditions, drawing from follow-up data on over 8000 patients. We systematically addressed the controversies surrounding FMT's clinical application. We delved into key issues such as its technical nature, evaluation methods, microbial restoration mechanisms, and impact on the host-microbiota interactions. Additionally, we explored the potential colonization patterns of FMT-engrafted new microbiota throughout the entire intestine and elucidated the specific pathways through which the new microbiota modulates host immunity, metabolism, and genome.

The Gut-Brain-Microbiota Connection and Its Role in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a group of complex neurodevelopmental conditions with a heterogeneous and multifactorial etiology that is not yet fully understood. Among the various factors that may contribute to ASD development, alterations in the gut microbiota have been increasingly recognized. Microorganisms in the gastrointestinal tract play a crucial role in the gut-brain axis (GBA), affecting nervous system development and behavior. Dysbiosis, or an imbalance in the microbiota, has been linked to both behavioral and gastrointestinal (GI) symptoms in individuals with ASD. The microbiota interacts with the central nervous system through mechanisms such as the production of short-chain fatty acids (SCFAs), the regulation of neurotransmitters, and immune system modulation. Alterations in its composition, including reduced diversity or an overabundance of specific bacterial taxa, have been associated with the severity of ASD symptoms. Dietary modifications, such as gluten-free or antioxidant-rich diets, have shown potential for improving gut health and alleviating behavioral symptoms. Probiotics, with their anti-inflammatory properties, may support neural health and reduce neuroinflammation. Fecal microbiota transplantation (FMT) is being considered, particularly for individuals with persistent GI symptoms. It has shown promising outcomes in enhancing microbial diversity and mitigating GI and behavioral symptoms. However, its limitations should be considered, as discussed in this narrative review. Further research is essential to better understand the long-term effects and safety of these therapies. Emphasizing the importance of patient stratification and phenotype characterization is crucial for developing personalized treatment strategies that account for individual microbiota profiles, genetic predispositions, and coexisting conditions. This approach could lead to more effective interventions for individuals with ASD. Recent findings suggest that gut microbiota may play a key role in innovative therapeutic approaches to ASD management.

L-tyrosine alleviates autism-like behavior in mice by remodeling the gut microbiota

Autism spectrum disorder (ASD) is characterized by impaired social interaction and repetitive stereotyped behavior, and effective interventions for the core autistic symptoms are currently limited. This study examines the protective role of L-tyrosine in alleviating ASD-like behavioral disorders in a valproic acid (VPA)-induced ASD mouse model and explores the underlying mechanisms via integrated multi-omics. We first investigated the potential of dietary L-tyrosine in mitigating autistic behavior. Subsequently, 16S rRNA sequencing, hippocampal transcriptomics, and neurotransmitter metabolome were employed to elucidate the underlying mechanism. Further, we conducted transplantation of the L-tyrosine-regulated microbiota in VPA-induced ASD mice. The results showed that L-tyrosine supplementation significantly mitigates ASD-like behavioral disorders, alleviates social communication deficits, and reduces repetitive behavior in autistic mice. L-tyrosine also attenuates the neuronal loss caused by VPA treatment in the DG and CA1 hippocampal regions in mice. The hippocampi of the L-tyrosine-treated mouse model for ASD displays modified gene expression profiles and different neurotransmitter levels. L-tyrosine also mitigates colonic barrier damage and amends the gut microbial composition and function. The integrative transcriptomic, metabolomic, and microbiome analysis shows strong connections between the hippocampal genes, neurotransmitters, and gut microbiota affected by L-tyrosine. The transplantation of microbiota from L-tyrosine-treated mice to VPA-induced ASD mice recipients recapitulated the preventive and protective effects of L-tyrosine on autistic behavior disorders. These findings suggest that dietary L-tyrosine may represent a viable, effective treatment option for managing the physiological and behavioral deficits associated with ASD.

Kismet/CHD7/CHD8 affects gut microbiota, mechanics, and the gut-brain axis in Drosophila melanogaster

The gut microbiome affects brain and neuronal development and may contribute to the pathophysiology of neurodevelopmental disorders. However, it is unclear how risk genes associated with such disorders affect gut physiology in a manner that could impact microbial colonization and how the mechanical properties of the gut tissue might play a role in gut-brain bidirectional communication. To address this, we used Drosophila melanogaster with a null mutation in the gene kismet, an ortholog of chromodomain helicase DNA-binding protein (CHD) family members CHD7 and CHD8. In humans, these are risk genes for neurodevelopmental disorders with co-occurring gastrointestinal symptoms. We found that kismet mutant flies have a significant increase in gastrointestinal transit time, indicating the functional homology of kismet with CHD7/CHD8 in vertebrates. Rheological characterization of dissected gut tissue revealed significant changes in the mechanics of kismet mutant gut elasticity, strain stiffening behavior, and tensile strength. Using 16S rRNA metagenomic sequencing, we also found that kismet mutants have reduced diversity and abundance of gut microbiota at every taxonomic level. To investigate the connection between the gut microbiome and behavior, we depleted gut microbiota in kismet mutant and control flies and quantified the flies' courtship behavior. Depletion of gut microbiota rescued courtship defects of kismet mutant flies, indicating a connection between gut microbiota and behavior. In striking contrast, depletion of the gut microbiome in the control strain reduced courtship activity, demonstrating that antibiotic treatment can have differential impacts on behavior and may depend on the status of microbial dysbiosis in the gut prior to depletion. We propose that Kismet influences multiple gastrointestinal phenotypes that contribute to the gut-microbiome-brain axis to influence behavior. We also suggest that gut tissue mechanics should be considered as an element in the gut-brain communication loop, both influenced by and potentially influencing the gut microbiome and neurodevelopment.

Autism Spectrum Disorder, Oral Implications, and Oral Microbiota

Background/Objectives: Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by difficulties in social interaction, communication, and repetitive behaviors. Recent evidence indicates a significant relationship between ASD and imbalances in microbiota, particularly in the oral and gastrointestinal areas. This review examines the impact of oral microbiota, self-injurious behaviors (SIB), sensory sensitivity, and dietary choices on the comorbidities associated with ASD. Methods: An extensive literature review was conducted using PubMed and Scopus. The focus was on human studies with full-text availability, utilizing search terms related to ASD, oral health, oral microbiota, and neurodevelopmental disorders. The research was evaluated for methodological quality and its relevance to the connections between microbiota, oral health, and ASD. Results: Individuals with ASD face unique oral health challenges, including injuries from self-injurious behaviors and increased sensory sensitivity, which complicate oral hygiene and care. Selective eating can lead to nutritional deficiencies and worsen oral health issues. Dysbiosis in oral and gut microbiota, marked by altered levels of acetate, propionate, and butyrate, interferes with gut-brain and oral-brain connections, contributing to behavioral and neurological symptoms. Treatment options such as probiotics, fecal microbiota transfer, and sensory integration therapies can potentially alleviate symptoms and improve quality of life. Conclusions: The relationship between ASD, oral health, and microbiota suggests a bidirectional influence through neuroinflammatory mechanisms and metabolic disturbances. Proactive strategies focusing on microbiota and dental health may help reduce comorbidities and enhance the overall management of ASD, underscoring the need for further research into microbiota-host interactions and their therapeutic potential.

Intervention and research progress of gut microbiota-immune-nervous system in autism spectrum disorders among students

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by difficulties in social interaction and communication, repetitive and stereotyped behaviors, restricted interests, and sensory abnormalities. Its etiology is influenced by both genetic and environmental factors, with no definitive cause identified and no specific pharmacological treatments available, posing a significant burden on patients' families and society. In recent years, research has discovered that gut microbiota dysbiosis plays a crucial role in the pathogenesis of ASD. The gut microbiota can influence brain function and behavior through the gut-brain axis via the nervous system, immune system, and metabolic pathways. On the one hand, specific gut microbes such as Clostridium and Prevotella species are found to be abnormal in ASD patients, and their metabolic products, like short-chain fatty acids, serotonin, and GABA, are also involved in the pathological process of ASD. On the other hand, ASD patients exhibit immune system dysfunction, with gut immune cells and related cytokines affecting neural activities in the brain. Currently, intervention methods targeting the gut microbiota, such as probiotics, prebiotics, and fecal microbiota transplantation, have shown some potential in improving ASD symptoms. However, more studies are needed to explore their long-term effects and optimal treatment protocols. This paper reviews the mechanisms and interrelationships among gut microbiota, immune system, and nervous system in ASD and discusses the challenges and future directions of existing research, aiming to provide new insights for the prevention and treatment of ASD.

Assessment of ecological fidelity of human microbiome-associated mice in observational studies and an interventional trial

Composition and function of the gut microbiome is associated with diverse health conditions and treatment responses. Human microbiota-associated (HMA) mouse models are used to establish causal links for these associations but have important limitations. We assessed the fidelity of HMA mouse models to recapitulate ecological responses to a microbial consortium using stools collected from a human clinical trial. HMA mice were generated using different routes of consortium exposure and their ecological features were compared to human donors by metagenomic sequencing. HMA mice were more similar in gut composition to other mice than their respective human donors, with taxa including Akkermansia muciniphila and Bacteroides species enriched in mouse recipients. A limited repertoire of microbes was able to engraft into HMA mice regardless of route of consortium exposure. In publicly available HMA mouse datasets from four distinct health conditions, we confirmed our observation that a taxonomically restricted set of microbes reproducibly engrafts in HMA mice and observed that stool microbiome composition of HMA mice were more like other mice than their human donor. Our data suggest that HMA mice are limited models to assess the ecological impact of microbial consortia, with ecological effects in HMA mice being more strongly associated with host species than donor stool ecology or ecological responses to treatment in humans. Comparisons to published studies suggest this may be due to comparatively large host-species effects that overwhelm ecological effects of treatment in humans that HMA models aim to recapitulate.

Aging and neurodegeneration: when systemic dysregulations affect brain macrophage heterogeneity

Microglia, the major population of brain resident macrophages, differentiate from yolk sac progenitors in the embryo and play multiple nonimmune roles in brain organization throughout development and life. Various microglia subtypes have been described by transcriptomic and proteomic signatures, involved metabolic pathways, morphology, intracellular complexity, time of residency, and ontogeny, both in development and in disease settings. Such macrophage heterogeneity increases with aging or neurodegeneration. Monocytes' infiltration and differentiation into monocyte-derived macrophages (MDMs) in the brain contribute to this diversity. Microbiota's role in brain diseases has been recently highlighted, revealing how microbial signals, such as metabolites, influence microglia and MDMs. In this brief review, we describe how these signals can influence microglia through their sensome and shape MDMs from their development in the bone marrow to their differentiation in the brain. Monocytes could then be a crucial player in the constitution of a dysbiotic gut-brain axis in neurodegenerative diseases and aging.

Deconstruct the link between gut microbiota and neurological diseases: application of Mendelian randomization analysis

Background

Recent research on the gut-brain axis has deepened our understanding of the correlation between gut bacteria and the neurological system. The inflammatory response triggered by gut microbiota may be associated with neurodegenerative diseases. Additionally, the impact of gut microbiota on emotional state, known as the "Gut-mood" relationship, could play a role in depression and anxiety disorders.

Results

This review summarizes recent data on the role of gut-brain axis in the pathophysiology of neuropsychiatric and neurological disorders including epilepsy, schizophrenia, Alzheimer's disease, brain cancer, Parkinson's disease, bipolar disorder and stroke. Also, we conducted a Mendelian randomization study on seven neurological disorders (Epilepsy, schizophrenia, Alzheimer's disease, brain cancer, Parkinson's disease, bipolar disorder and stroke). MR-Egger and MR-PRESSO tests confirmed the robustness of analysis against horizontal pleiotropy.

Conclusions

By comparing the protective and risk factors for neurological disorders found in our research and other researches, we can furtherly determine valuable indicators for disease evolution tracking and potential treatment targets. Future research should explore extensive microbiome genome-wide association study datasets using metagenomics sequencing techniques to deepen our understanding of connections and causality between neurological disorders.

The Impact of Valproic Acid on Microbiota in a Mouse Model of Autism Spectrum Disorder

Background

Autism spectrum disorder (ASD) is a complex neuropsychiatric condition with a multifactorial etiology, involving both genetic predisposition and environmental factors. Valproic acid (VPA), a commonly used antiepileptic drug, has been shown to induce ASD-like behaviors in rodent models, making it a valuable tool for studying the pathophysiology of ASD. This study aims to explore the effects of VPA on behavior and the microbiota in a mouse model of ASD.

Methods

C57BL/6 mice were used in this study, with pregnant females receiving a single intraperitoneal injection of VPA (450 mg/kg) or a saline solution on gestational day E12.5. Behavioral assessments, including the Three-Chamber Social Test, Elevated Plus Maze, Marble Burying Test, Open Field Test, and Light-Dark Box Test, were conducted on 8-week-old mice. Oral and fecal samples were collected for microbiota analysis, and gene expression profiling was performed on brain samples.

Results

VPA-treated mice exhibited significant deficits in social interaction, anxiety-like behaviors, and repetitive actions. Microbiota analysis revealed significant shifts in the composition of both oral and fecal microbial communities in VPA-treated mice, with reductions in alpha diversity and changes in the relative abundance of specific taxa. Gene set variation analysis of mice harboring VPA-induced microbiota identified notable discrepancies in metabolic pathways, suggesting that the dysbiosis may modulate the expression of genes involved in critical metabolic processes.

Conclusion

The present study provides evidence that VPA exposure during early development can induce ASD-like behaviors in mice, along with significant changes in the composition of the microbiota. These findings underscore the complex interplay between environmental factors, such as VPA, and the microbiota in the pathophysiology of ASD. The study lays the groundwork for future research aimed at developing targeted interventions to mitigate the symptoms of ASD and other neuropsychiatric disorders, potentially through modulating the microbiota-gut-brain axis.

Ex Vivo Analysis of the Effect of Endoscopic Premedications on the Microbiota Profile in Gastric Juice

Background and Aim

Dimethicone (GAS), lidocaine (XYL), and protease (PRO) are commonly used as premedications during esophagogastroduodenoscopy (EGD). However, the effects of these drugs on the gastric microbiota remain unexplored. Therefore, we aimed to investigate the effects of these premedications on gastric juice collected from patients undergoing EGD.

Methods

Gastric juice was endoscopically aspirated from six patients and divided into six aliquots for in vitro analysis. The samples were mixed with premedications in corresponding treatment sets: GAS, XYL, PRO, MIX (a mixture of GAS, XYL, and PRO), and control (CTL1 and 2; no medication treatment). After extraction of microbial DNA from the treated samples, the 16S rRNA amplicon sequence was analyzed to determine the microbiota profile in terms of (1) the amount of genomic DNA (gDNA), (2) α-diversity indices, Shannon index, number of observed operational taxonomic units (OTUs), and Chao1 index, (3) weighted and unweighted UniFrac distances, and (4) the relative abundance of phyla and genera.

Results

The total amount of extracted gDNA did not significantly differ between the six groups. The α-diversity indices did not significantly differ between treatment groups. Although GAS, PRO, and MIX differed significantly from the technical replicates in the weighted UniFrac distance (p = 0.03 all), no significant difference was observed in the unweighted UniFrac distance. However, significant differences were observed in the relative abundance of several bacterial microbiota at the phylum and genus levels.

Conclusions

Premedications affect the microbiota profile of specific phylum- and genus-level bacterial groups. Trial Registration: University Hospital Medical Information Network Clinical Trials Registry: UMIN-CTR 000040192 and UMIN-CTR 000051289.

High prevalence of periodontal disease and periodontopathogen colonization in adults with autism spectrum disorder: a pilot study

Introduction

Alteration of the oral microbiome could potentially play a role in the etiology of certain patients with Autism Spectrum Disorder (ASD), similar to the established link between gut microbiota dysbiosis and ASD. Most studies have assessed oral microbiota in children only and few have explored the oral flora composition in adults with ASD.

Methods

In our study, periodontal and dental status was evaluated in 30 adults with ASD using appropriate indices. Oral microbiota samples were collected in crevicular fluid and supra-gingival plaque at inflamed sites in each patient and analyzed using PCR for bacteria and qPCR for protozoa. Demographic data, co-morbidities, medication and oral hygiene habits were also collected.

Results

A total of 86.7% of the patients recruited suffering from severe ASD had periodontal disease and 67% had a high level of supra-gingival plaque. Two major periodontopathogens belonging to the red complex, Treponema denticola and Tannerella forsythia, were both detected in the supra-gingival plaque of 86.2% of patients and in the gingival crevicular fluid of 80 and 86.7% of patients, respectively. Certain microorganisms were statistically more frequently detected in patients with digestive disorders and taking certain medications.

Discussion

The oral microbiota composition of the adults with ASD showed significant differences compared to neurotypical individuals, particularly in the prevalence of the specific microorganisms P. gingivalis, T. tenax and E. gingivalis ST1. The detection frequency of periodontitis and periodontopathogens may have been underestimated due to the lack of cooperation of the adults with ASD during clinical examination and microbiota sampling. Further studies on larger cohorts are needed to consolidate these results to gain a better understanding of variations in oral microbiota.

Gut microbiome-derived lipopolysaccharides aggravate cognitive impairment via TLR4-mediated inflammatory signaling in neonatal rats following hypoxic-ischemic brain damage

Hypoxic-ischemic brain damage (HIBD) is a leading cause of infant mortality and neurological disabilities in children. Recent evidence indicates that gut microbiota significantly contributes to the development of inflammation and cognitive impairments following brain injury. However, the mechanisms by which gut microbiota influence inflammation and cognitive function in the neonates after HIBD are not well understood. This study established a neonatal rat model of HIBD by the classic Rice-Vannucci technique to investigate gut dysbiosis following hypoxic-ischemic (HI) insult and to elucidate the causal relationship between gut dysbiosis and cognitive impairments. Our results demonstrated that HI insult resulted in significant gut microbial dysbiosis, characterized by an expansion of Enterobacteriaceae. This dysbiosis was associated with intestinal barrier damage, lipopolysaccharides (LPS) leakage, and systemic inflammation. Conversely, administration of aminoguanidine (AG) to inhibit Enterobacteriaceae overgrowth restored intestinal barrier integrity and reduced systemic inflammation. Importantly, AG treatment effectively suppressed microglial activation, neuronal damage, and cognitive impairments in the neonatal rats subjected to HI insult. Additionally, RNA sequencing analysis revealed that differentially expressed genes in both colonic and hippocampal tissues were primarily associated with inflammation and neuronal apoptosis after HI insult. Further mechanistic exploration revealed that AG treatment mitigated intestinal LPS leakage, thereby reducing the activation of the TLR4/MyD88/NF-κB signaling pathway and production of the downstream inflammatory cytokines in both the colon and hippocampus. Notably, fecal microbiota transplantation (FMT) from the HIBD rats to the antibiotic cocktail-treated recipient rats resulted in microglial activation, neuronal damage, and cognitive impairments in the recipients. However, these adverse effects were effectively mitigated in the recipient rats that received FMT from the AG-treated donors, as well as in those undergoing hippocampal TLR4 knockdown. In conclusion, our findings indicate that LPS derived from gut Enterobacteriaceae overgrowth plays a critical role in the TLR4-mediated inflammatory signaling, providing a novel microbiota-based therapeutic approach for cognitive impairments following neonatal HIBD.

The microbiome as a modulator of neurological health across the maternal-offspring interface

The maternal microbiome is emerging as an important factor that influences the neurological health of mothers and their children. Recent studies highlight how microbial communities in the maternal gut can shape early-life development in ways that inform long-term health trajectories. Research on the neurodevelopmental effects of maternal microbiomes is expanding our understanding of the microbiome-gut-brain axis to include signaling across the maternal-offspring unit during the perinatal period. In this Review, we synthesize existing literature on how the maternal microbiome modulates brain function and behavior in both mothers and their developing offspring. We present evidence from human and animal studies showing that the maternal microbiome interacts with environmental factors to impact risk for neurodevelopmental abnormalities. We further discuss molecular and cellular mechanisms that facilitate maternal-offspring crosstalk for neuromodulation. Finally, we consider how advancing understanding of these complex interactions could lead to microbiome-based interventions for promoting maternal and offspring health.

Gut microbiotas, inflammatory factors, and mental-behavioral disorders: A mendelian randomization study

BACKGROUND

The Mendelian randomization approach has emerged as a powerful tool, leveraging genetic variations as natural random experiments to minimize confounding and infer causality with unique advantages. Previous research has highlighted the crucial roles of gut microbiotas and inflammatory factors in mental-behavioral disorders, albeit to varying degrees. However, the precise causal relationship between gut microbiotas and mental-behavioral disorders remains elusive, and the potential role of inflammatory factors as mediators in this process is unclear.

METHODS

To investigate the associations between gut microbiotas, inflammatory factors, and mental-behavioral disorders, we pooled data from large-scale genome-wide association studies (GWAS). Our study screened 27 diseases, encompassing nine subtypes of mental-behavioral disorders: neurodevelopmental disorders, eating disorders, sleep disorders, schizophrenia spectrum disorders, stress- and trauma-related disorders, mood and affective disorders, cognitive and executive function disorders, personality and somatization disorders, and addiction disorders. Mendelian randomization(MR) was employed to assess causal relationships between gut microbiotas, inflammatory factors, and these mental-behavioral disorders, with inverse variance weighting (IVW) as the primary statistical method. Furthermore, we explored whether inflammatory factors mediate the relationship between gut microbiotas and mental-behavioral disorders.

RESULTS

Having investigated the intricate interplay among gut microbiota, inflammatory factors, and mental-behavioral disorders, we have identified nine pivotal inflammatory factors that intricately regulate the progression of eight distinct disease subtypes. Noteworthy among these findings, levels of CC motif chemokine ligand 28 (CCL28) and CC motif chemokine ligand 25 (CCL25) are associated with the progression of attention-deficit/hyperactivity disorder (ADHD), interleukin-18 (IL-18) levels are linked to anorexia, IL-12β levels are related to schizophrenia (SZ) progression, IL-8 levels are associated with manic episodes, and IL-10 and monocyte chemoattractant protein-2 (MCP-2) levels are closely related to enduring personality changes(EPC). Additionally, fibroblast growth factor 19 (FGF19) levels are associated with cognitive disorders, while C-X-C motif chemokine ligand 1 (CXCL1) levels are related to executive functioning.

CONCLUSION

Gut microbiotas and mental-behavioral disorders have causal relationships, with inflammatory factors mediating the pathway from gut microbiotas to these disorders.

Effects of gastrointestinal symptoms on the efficacy of washed microbiota transplantation in patients with autism

Objective

Washed microbiota transplantation (WMT) has emerged as a promising therapeutic strategy for autism spectrum disorder (ASD), though the factors that influence its efficacy remain poorly understood. This study explores the impact of gastrointestinal (GI) symptoms on the effectiveness of WMT in ASD.

Methods

Clinical data encompassing ASD symptoms, GI disturbances, and sleep disorders were collected from patients with ASD undergoing WMT. The therapeutic impact of WMT and the contributing factors to its efficacy were assessed.

Results

WMT significantly reduced scores on the Aberrant Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Sleep Disturbance Scale for Children (SDSC), alongside a significant reduction in the incidence of constipation, abnormal stool forms, and diarrhea (all p < 0.05). After six courses of WMT, substantial reductions were observed in ABC, CARS, and SDSC scores, with increased treatment courses correlating with greater improvement (p < 0.05). Multiple linear regression analysis revealed that WMT efficacy was enhanced in patients with pre-existing GI symptoms (diarrhea: β = 0.119, p < 0.001; abnormal stool form: β = 0.201, p < 0.001) and those receiving a higher number of treatment courses (β = 0.116, p < 0.001). Additionally, the analysis indicated that treatment outcomes were more favorable in patients who had not undergone adjunct interventions (β = -0.041, p = 0.002), had a longer disease duration (β = 0.168, p = 0.007), and exhibited more severe disease symptoms (β = 0.125, p < 0.001).

Conclusion

WMT significantly alleviates both ASD and GI symptoms, along with sleep disturbances, in affected individuals. Six treatment courses resulted in notable improvement, with increased course numbers further improving therapeutic outcomes. Furthermore, pre-treatment GI symptoms, such as diarrhea and abnormal stool forms, may influence the effectiveness of WMT. Notably, patients who did not receive additional interventions, had a prolonged disease duration, and presented with more severe symptoms experienced markedly improved treatment responses.

The effect of culturing temperature on the growth of the most dominant bacterial species of human gut microbiota and harmful bacterial species

In recent years, the gut microbiota has attracted attention due to reported associations with various diseases and health conditions. Gut bacteria have been constantly cultured at 37°C, potentially limiting the understanding of the interaction between them and the host. However, the most dominant human gut microbial species have not been extensively cultured at temperatures other than 37°C. In this study, we analyzed the effects of various culturing temperatures on the growth of the 51 most dominant commensal species as well as 3 harmful bacteria, including Clostridium perfringens, a food poisoning bacterium, in the human intestine. The results showed that the growth of predominant gut microbes varied minimally at body temperatures conducive to human survival but that the growth of several bacteria involved in butyrate production in the intestinal lumen was repressed at temperatures other than 37°C. When cultured at 50°C, the growth of C. perfringens was less inhibited than that of other bacterial species. In addition, the growth of some gut bacteria was unaffected by a body temperature range that was not suitable for human survival.

Exploring the microbiota-gut-brain axis: impact on brain structure and function

The microbiota-gut-brain axis (MGBA) plays a significant role in the maintenance of brain structure and function. The MGBA serves as a conduit between the CNS and the ENS, facilitating communication between the emotional and cognitive centers of the brain via diverse pathways. In the initial stages of this review, we will examine the way how MGBA affects neurogenesis, neuronal dendritic morphology, axonal myelination, microglia structure, brain blood barrier (BBB) structure and permeability, and synaptic structure. Furthermore, we will review the potential mechanistic pathways of neuroplasticity through MGBA influence. The short-chain fatty acids (SCFAs) play a pivotal role in the MGBA, where they can modify the BBB. We will therefore discuss how SCFAs can influence microglia, neuronal, and astrocyte function, as well as their role in brain disorders such as Alzheimer's disease (AD), and Parkinson's disease (PD). Subsequently, we will examine the technical strategies employed to study MGBA interactions, including using germ-free (GF) animals, probiotics, fecal microbiota transplantation (FMT), and antibiotics-induced dysbiosis. Finally, we will examine how particular bacterial strains can affect brain structure and function. By gaining a deeper understanding of the MGBA, it may be possible to facilitate research into microbial-based pharmacological interventions and therapeutic strategies for neurological diseases.

Single-cell delineation of the microbiota-gut-brain axis: Probiotic intervention in Chd8 haploinsufficient mice

Emerging research underscores the gut microbiome's impact on the nervous system via the microbiota-gut-brain axis, yet comprehensive insights remain limited. Using a CHD8-haploinsufficient model for autism spectrum disorder (ASD), we explored host-gut microbiota interactions by constructing a single-cell transcriptome atlas of brain and intestinal tissues in wild-type and mutant mice across three developmental stages. CHD8 haploinsufficiency caused delayed development of radial glial precursors and excitatory neural progenitors in the E14.5 brain, inflammation in the adult brain, immunodeficiency, and abnormal intestinal development. Selective CHD8 knockdown in intestinal epithelial cells generated Chd8ΔIEC mice, which exhibited normal sociability but impaired social novelty recognition. Probiotic intervention with Lactobacillus murinus selectively rescued social deficits in Chd8ΔIEC mice, with single-cell transcriptome analysis revealing underlying mechanisms. This study provides a detailed single-cell transcriptomic dataset of ASD-related neural and intestinal changes, advancing our understanding of the gut-brain axis and offering potential therapeutic strategies for ASD.

Linking Gut Microbiota and Stereotypic Behavior of Endangered Species Under Ex Situ Conservation: First Evidence from Sun Bears

Integrative conservation research on animal behavior and nutritional health can contribute to the ex situ conservation of endangered species. Stereotypic behavior, a repetitive behavior without practical function, is associated with animal welfare in its manner and frequency for captive animals. Exploring the potential relationship between stereotypic behavior and internal factors, such as intestinal flora, could improve ex situ conservation, especially for endangered species. In this study, we analyzed the typical behavior characteristics of the endangered sun bears (Helarctos malayanus) under captive conditions based on the behavior sampling method. The seasonal and annual changes in the intestinal flora of H. malayanus in captivity were studied by 16S rDNA high-throughput sequencing technology based on non-invasive fecal sample collection. This study provides the first evidence of a potential association between the gut microbiota and stereotypic behavior characteristics of captive H. malayanus. The results can significantly improve our understanding of the stereotypical behavior of H. malayanus in captivity and contribute to the captive breeding and conservation efforts of this endangered species.

Vagus nerve stimulation and gut microbiota interactions: A novel therapeutic avenue for neuropsychiatric disorders

The rising prevalence of treatment-resistant neuropsychiatric disorders underscores the need for innovative and effective treatment strategies. The gut microbiota (GM) plays a pivotal role in the progression of these diseases, influencing the brain and mental health through the gut-brain axis (GBA). The vagus nerve plays a significant role in the GBA, making it a key area of focus for potential novel therapeutic interventions. Vagus nerve stimulation (VNS) was introduced and approved as a treatment for refractory forms of some neuropsychological disorders, such as depression and epilepsy. Considering its impact on several brain regions that play a vital part in mood, motivation, affection, and cognitive function, the VNS has shown significant therapeutic potential for treating a variety of neuropsychiatric disorders. Using VNS to target the bidirectional communication pathways linking the GM and the VN could present an exciting and novel approach to treating neuropsychological disorders. Imbalances in the GM, such as dysbiosis, can impair the communication pathways between the gut and the brain, contributing to the development of neuropsychological disorders. VNS shows potential for modulating these interconnected systems, helping to restore balance. Interestingly, the composition of the GM may also influence the effectiveness of VNS, as it has the potential to modify the brain's response to this therapeutic approach. This study provides a comprehensive analysis of a relatively unexplored but noteworthy interaction between VNS and GM in the treatment of neuropsychiatric disorders. In addition, we discussed the mechanisms, therapeutic potential, and clinical implications of VNS on the GBA across neuropsychiatric disorders.

The gut microbiome promotes locomotion of Drosophila larvae via octopamine signaling

The gut microbiome is a key partner of animals, influencing various aspects of their physiology and behaviors. Among the diverse behaviors regulated by the gut microbiome, locomotion is vital for survival and reproduction, although the underlying mechanisms remain unclear. Here, we reveal that the gut microbiome modulates the locomotor behavior of Drosophila larvae via a specific neuronal type in the brain. The crawling speed of germ-free (GF) larvae was significantly reduced compared to the conventionally reared larvae, while feeding and excretion behaviors were unaffected. Recolonization with Acetobacter and Lactobacillus can fully and partially rescue the locomotor defects in GF larvae, respectively, probably due to the highest abundance of Acetobacter as a symbiotic bacterium in the larval gut, followed by Lactobacillus. Moreover, the gut microbiome promoted larval locomotion, not by nutrition, but rather by enhancing the brain levels of tyrosine decarboxylase 2 (Tdc2), which is an enzyme that synthesizes octopamine (OA). Overexpression of Tdc2 rescued locomotion ability in GF larvae. These findings together demonstrate that the gut microbiome specifically modulates larval locomotor behavior through the OA signaling pathway, revealing a new mechanism underlying larval locomotion regulated by the gut microbiome.

Berberine Alleviates Kainic Acid-Induced Acute Epileptic Seizures in Mice via Reshaping Gut Microbiota-Associated Lipid Metabolism

BACKGROUND

Berberine (BBR) has been reported to mitigate epileptic seizures. However, the potential mechanism of its anti-seizure effect remains uncharacterized.

AIMS

This study aimed to investigate the protective effect of BBR on acute epileptic seizures induced by kainic acid (KA) in mice and further explore its mechanism of action in the aspect of analysis of gut microbiota.

MATERIALS AND METHODS

The protective effect of BBR against acute epileptic seizures was assessed via Racine score and Nissl training. Alterations of gut microbiota and metabolites in seizure mice after BBR treatment were analyzed through 16S sequencing and lipidomics, respectively.

RESULTS

Our results showed that the BBR remarkably alleviated acute epileptic seizures and hippocampal neuron damage in KA-induced mice. The analysis of gut microbiota indicated that BBR reduced the acute epileptic seizures in KA-induced mice by increasing the abundance of Bacteroidetes and Alloprevotella, regulating short-chain fatty acids (SCFAs). Results of lipidomics also identified 21 candidate metabolites in the colon and hippocampus possibly involved in the protective effect of BBR against acute seizures.

CONCLUSION

These findings suggest that BBR exerts neuroprotection against KA-induced epileptic seizures through remodeling gut microbiota-associated lipid metabolism in the colon and hippocampus. BBR may serve as a valuable candidate drug for curing patients with epilepsy.

Comparison of Gut Microbiota in Two Different Maternal Exposure Models of Autism Spectrum Disorder in Mice

Background

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders with unknown etiology and unclear pathogenesis. Although construction of animal models of ASD using chemical exposure during pregnancy is a mature technique, the gut microbiota of these exposure models induced using different chemicals in mice have not been compared.

Methods

To compare the effects of exposure to different chemicals during pregnancy on the composition of gut microbiota in offspring, we treated Institute of Cancer Research (ICR) mice with lipopolysaccharide (LPS) and valproic acid (VPA) during pregnancy to construct different offspring ASD mouse models. After successful model construction, the gut microbiota of these models were studied.

Results

After adjusting for the random effects of the litter, the two groups showed a significant reduction in social time (social deficits) and an increase in self-grooming behaviors (repetitive and stereotyped behaviors). Gut microbiota analysis revealed significant changes, mostly a decrease, in the abundance of four phyla, 52 genera, and 41 species in the two types of ASD models. Several different gut microbes could be related to the development of ASD.

Conclusions

Chemicals exposure during pregnancy induces ASD-related behavioral abnormalities in offspring mice. Importantly, exposure to different chemicals during pregnancy produces varying degrees of effects on gut microbiota composition in offspring ASD models. This finding can provide a reference for studies on the etiology and pathogenesis of ASD.

Integrative analysis of intestinal flora and untargeted metabolomics in attention-deficit/hyperactivity disorder

Attention Deficit Hyperactivity Disorder (ADHD) is a clinically common neurodevelopmental disorder of the brain. In addition to genetic factors, an imbalance in gut flora may also play a role in the development of ADHD. Currently, it is critical to investigate the function of gut flora and related metabolites, which may form the fundamental basis of bidirectional cross-linking between the brain and the gut, in addition to focusing on the changed gut flora in ADHD. This study aimed to investigate the possible relationship between changes in gut flora and metabolites and ADHD by analyzing metagenome and untargeted metabolomics of fecal samples from ADHD patients. Specifically, we attempted to identify key metabolites and the metabolic pathways they are involved in, as well as analyze in detail the structure and composition of the gut flora of ADHD patients. In order to further investigate the relationship between gut flora and ADHD symptoms, some behavioral studies were conducted following the transplantation of gut flora from ADHD patients into rats. The results of the metagenome analysis revealed several distinct strains, including Bacteroides cellulosilyticus, which could be important for diagnosing ADHD. Additionally, the ADHD group showed modifications in several metabolic pathways and metabolites, including the nicotinamide and nicotinic acid metabolic pathways and the metabolite nicotinamide in this pathway. The behavioral results demonstrated that rats with ADHD gut flora transplants displayed increased locomotor activity and interest, indicating that the onset of behaviors such as ADHD could be facilitated by the flora associated with ADHD. This research verified the alterations in gut flora and metabolism observed in ADHD patients and provided a list of metabolites and flora that were significantly altered in ADHD. Simultaneously, our findings revealed that modifications to the microbiome could potentially trigger behavioral changes in animals, providing an experimental basis for comprehending the function and influence of gut flora on ADHD. These results might provide new perspectives for the development of novel treatment strategies.

The neurobiological mechanisms underlying the effects of exercise interventions in autistic individuals

Autism spectrum disorder is a pervasive and heterogeneous neurodevelopmental condition characterized by social communication difficulties and rigid, repetitive behaviors. Owing to the complex pathogenesis of autism, effective drugs for treating its core features are lacking. Nonpharmacological approaches, including education, social-communication, behavioral and psychological methods, and exercise interventions, play important roles in supporting the needs of autistic individuals. The advantages of exercise intervention, such as its low cost, easy implementation, and high acceptance, have garnered increasing attention. Exercise interventions can effectively improve the core features and co-occurring conditions of autism, but the underlying neurobiological mechanisms are unclear. Abnormal changes in the gut microbiome, neuroinflammation, neurogenesis, and synaptic plasticity may individually or interactively be responsible for atypical brain structure and connectivity, leading to specific autistic experiences and characteristics. Interestingly, exercise can affect these biological processes and reshape brain network connections, which may explain how exercise alleviates core features and co-occurring conditions in autistic individuals. In this review, we describe the definition, diagnostic approach, epidemiology, and current support strategies for autism; highlight the benefits of exercise interventions; and call for individualized programs for different subtypes of autistic individuals. Finally, the possible neurobiological mechanisms by which exercise improves autistic features are comprehensively summarized to inform the development of optimal exercise interventions and specific targets to meet the needs of autistic individuals.

Unraveling the Connections: Eating Issues, Microbiome, and Gastrointestinal Symptoms in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by challenges in social communication, restricted interests, and repetitive behaviors. It is also associated with a high prevalence of eating disorders, gastrointestinal (GI) symptoms, and alterations in gut microbiota composition. One of the most pressing concerns is food selectivity. Various eating disorders, such as food neophobia, avoidant/restrictive food intake disorder (ARFID), specific dietary patterns, and poor-quality diets, are commonly observed in this population, often leading to nutrient deficiencies. Additionally, gastrointestinal problems in children with ASD are linked to imbalances in gut microbiota and immune system dysregulation. The aim of this narrative review is to identify previous associations between the gut-brain axis and gastrointestinal problems in ASD. We discuss the impact of the "microbiome-gut-brain axis", a bidirectional connection between gut microbiota and brain function, on the development and symptoms of ASD. In gastrointestinal problems associated with ASD, a 'vicious cycle' may play a significant role: ASD symptoms contribute to the prevalence of ARFID, which in turn leads to microbiota degradation, ultimately worsening ASD symptoms. Current data suggest a link between gastrointestinal problems in ASD and the microbiota, but the amount of evidence is limited. Further research is needed, targeting the correlation of a patient's microbiota status, dietary habits, and disease course.

An open window: the crucial role of the gut-brain axis in neurodevelopmental outcomes post-neurocritical illness

Among patients admitted to the pediatric intensive care unit, approximately 10% are discharged with a new functional morbidity. For those who were admitted with a neurocritical illness, the number can be as high as 60%. The most common diagnoses for a neurocritical illness admission include traumatic brain injury, status epilepticus, post-cardiac arrest, hypoxic ischemic encephalopathy, meningo/encephalitis, and stroke. The gut-brain axis is crucial to childhood development, particularly neurodevelopment. Alterations on either side of the bidirectional communication of the gut-brain axis have been shown to alter typical development and have been associated with autism spectrum disorder, anxiety, sleep disturbances, and learning disabilities, among others. For those patients who have experienced a direct neurologic insult, subsequent interventions may contribute to dysbiosis, which could compound injury to the brain. Increasing data suggests the existence of a critical window for both gut microbiome plasticity and neurodevelopment in which interventions could help or could harm and warrant further investigation.

Changes in RNA Splicing: A New Paradigm of Transcriptional Responses to Probiotic Action in the Mammalian Brain

Elucidating the gene regulatory mechanisms underlying the gut-brain axis is critical for uncovering novel gut-brain interaction pathways and developing therapeutic strategies for gut bacteria-associated neurological disorders. Most studies have primarily investigated how gut bacteria modulate host epigenetics and gene expression; their impact on host alternative splicing, particularly in the brain, remains largely unexplored. Here, we investigated the effects of the gut-associated probiotic Lacidofil® on alternative splicing across 10 regions of the rat brain using published RNA-sequencing data. The Lacidofil® altogether altered 2941 differential splicing events, predominantly, skipped exon (SE) and mutually exclusive exon (MXE) events. Protein-protein interactions and a KEGG analysis of differentially spliced genes (DSGs) revealed consistent enrichment in the spliceosome and vesicle transport complexes, as well as in pathways related to neurodegenerative diseases, synaptic function and plasticity, and substance addiction across brain regions. Using the PsyGeNET platform, we found that DSGs from the locus coeruleus (LConly), medial preoptic area (mPOA), and ventral dentate gyrus (venDG) were enriched in depression-associated or schizophrenia-associated genes. Notably, we highlight the App gene, where Lacidofil® precisely regulated the splicing of two exons causally involved in amyloid β protein-based neurodegenerative diseases. Although the splicing factors exhibited both splicing plasticity and expression plasticity in response to Lacidofil®, the overlap between DSGs and differentially expressed genes (DEGs) in most brain regions was rather low. Our study provides novel mechanistic insight into how gut probiotics might influence brain function through the modulation of RNA splicing.

Integrating 16S rRNA Gene Sequencing and Metabolomics Analysis to Reveal the Mechanism of L-Proline in Preventing Autism-like Behavior in Mice

BACKGROUND/OBJECTIVES

Autism spectrum disorder (ASD) is characterized by impaired social interaction and repetitive stereotyped behavior. Effective interventions for the core autistic symptoms are currently limited.

METHODS

This study employed a valproic acid (VPA)-induced mouse model of ASD to assess the preventative effects of L-proline supplementation on ASD-like behaviors. The method of 16S rRNA sequencing and untargeted metabolomics analyses were conducted to investigate the modulation of gut microbiota and gut metabolites by L-proline.

RESULTS

The results indicated that L-proline supplementation significantly prevented ASD-like behavioral disorders, including alleviating social communication deficits and reducing repetitive behavior in the ASD mice. The 16S rRNA sequencing analysis revealed that L-proline regulated the composition and structure of gut microbiota. L-Proline supplementation enhances the abundance of the Verrucomicrobia at the phylum level and the Akkermansia at the genus level, while concurrently reducing the abundance of the Patescibacteria at the phylum level, as well as the Ileibacterium, Candidatus_Saccharimonas, and Lachnospiraceae_UCG-006 at the genus level in the VPA-induced mouse model for ASD. Additionally, the untargeted metabolomics results indicated that L-proline also modified the gut metabolite profiles. Functional analysis of the gut microbiota and KEGG pathway enrichment analysis of differential metabolites between the L-proline-supplemented and VPA groups corroborated that L-proline decreased pathways related to nucleotide metabolism, taurine and hypotaurine metabolism, and pyruvate metabolism, while increasing pathways involved in alpha-linolenic acid metabolism and phenylalanine, tyrosine, and tryptophan biosynthesis. The integrative metabolomic and microbiome analyses showed strong connections between the gut metabolites and gut microbiota affected by L-proline. These findings suggest that the modulatory effects of L-proline on gut microbiota and its metabolites may play a crucial role in preventing autism in mice.

CONCLUSIONS

These findings suggest that dietary L-proline may represent a viable, effective option for preventing the physiological and behavioral deficits associated with ASD in mice.

The pediatric psychopharmacology of autism spectrum disorder: A systematic review - Part II: The future

Part I of this systematic review summarized the state-of-the-art of pediatric psychopharmacology for Autism Spectrum Disorder (ASD), a severe and lifelong neurodevelopmental disorder. The purpose of this Part II follow-up article is to provide a systematic overview of the experimental psychopharmacology of ASD. To this aim, we have first identified in the Clinicaltrials.gov website all the 157 pharmacological and nutraceutical compounds which have been experimentally tested in children and adolescents with ASD using the randomized placebo-controlled trial (RCT) design. After excluding 24 drugs already presented in Part I, a systematic review spanning each of the remaining 133 compounds was registered on Prospero (ID: CRD42023476555), performed on PubMed (August 8, 2024), and completed with EBSCO, PsycINFO (psychology and psychiatry literature) and the Cochrane Database of Systematic reviews, yielding a total of 115 published RCTs, including 57 trials for 23 pharmacological compounds and 48 trials for 17 nutraceuticals/supplements. Melatonin and oxytocin were not included, because recent systematic reviews have been already published for both these compounds. RCTs of drugs with the strongest foundation in preclinical research, namely arbaclofen, balovaptan and bumetanide have all failed to reach their primary end-points, although efforts to target specific patient subgroups do warrant further investigation. For the vast majority of compounds, including cannabidiol, vasopressin, and probiotics, insufficient evidence of efficacy and safety is available. However, a small subset of compounds, including N-acetylcysteine, folinic acid, l-carnitine, coenzyme Q10, sulforaphane, and metformin may already be considered, with due caution, for clinical use, because there is promising evidence of efficacy and a high safety profile. For several other compounds, such as secretin, efficacy can be confidently excluded, and/or the data discourage undertaking new RCTs. Part I and Part II summarize "drug-based" information, which will be ultimately merged to provide clinicians with a "symptom-based" consensus statement in a conclusive Part III, with the overarching aim to foster evidence-based clinical practices and to organize new strategies for future clinical trials.

Influential articles in autism and gut microbiota: bibliometric profile and research trends

Objective

Autism spectrum disorder (ASD) is a common neurodevelopmental disorder. Increasing evidence suggests that it is potentially related to gut microbiota, but no prior bibliometric analysis has been performed to explore the most influential works in the relationships between ASD and gut microbiota. In this study, we conducted an in-depth analysis of the most-cited articles in this field, aiming to provide insights to the existing body of research and guide future directions.

Methods

A search strategy was constructed and conducted in the Web of Science database to identify the 100 most-cited papers in ASD and gut microbiota. The Biblioshiny package in R was used to analyze and visualize the relevant information, including citation counts, country distributions, authors, journals, and thematic analysis. Correlation and comparison analyses were performed using SPSS software.

Results

The top 100 influential manuscripts were published between 2000 and 2021, with a total citation of 40,662. The average number of citations annually increased over the years and was significantly correlated to the year of publication (r = 0.481, p < 0.01, Spearman's rho test). The United States was involved in the highest number of publications (n = 42). The number of publications in the journal was not significantly related to the journal's latest impact factor (r = 0.016, p > 0.05, Spearman's rho test). Co-occurrence network and thematic analysis identified several important areas, such as microbial metabolites of short-chain fatty acids and overlaps with irritable bowel syndrome.

Conclusion

This bibliometric analysis provides the key information of the most influential studies in the area of ASD and gut microbiota, and suggests the hot topics and future directions. The findings of this study can serve as a valuable reference for researchers and policymakers, guiding the development and implementation of the scientific research strategies in this area.

Fecal microbiota transplantation alleviates neuronal Apoptosis, necroptosis and reactive microglia activation after ischemic stroke

OBJECTIVE

This study aims to delve into the mechanisms underlying the improvement of neurological function in rats with ischemic stroke through fecal microbiota transplantation.

METHODS

A total of fifty male Sprague-Dawley rats were categorized into four groups: Sham, MCAO, MCAO+vehicle and FMT. We assessed behavioral and pathological alterations in the rats using modified neurological function scoring and TTC staining.Additionally, Western blot and immunofluorescence were used to detect the expression levels of Apoptotic and Necroptosis markers in neurons of ischemic brain tissue, and immunofluorescence was used to analyze the degree of activation of microglia.

RESULTS

FMT group exhibited a decline in neurological function score compared to the MCAO and MCAO + vehicle group, accompanied by a reduction in infarct volume (P < 0.05). Relative to the SHAM group, the MCAO group displayed a significant increase in the expression levels of necroptosis-related proteins Phospho-RIP1, Phospho-RIP3, Phospho-MLKL, apoptotic proteins Bax and Cleaved caspase-3, and the iNOS positive microglia in ischemic brain tissue, while Bcl-2 expression was notably decreased (P < 0.05).Conversely, compared to the MCAO + vehicle group, the FMT group showed decreased expression levels of Phospho-RIP1, Phospho-RIP3, Phospho-MLKL, Bax, Cleaved caspase-3, and iNOS-positive microglia, while the expression of Bcl-2 was increased.

CONCLUSION

Fecal microbiota transplantation offers a promising approach to improving neurological function in rats with ischemic stroke by inhibiting neuronal apoptosis, necroptosis, and the polarization of inflammatory microglial cells.

Microbiota-neuroepithelial signalling across the gut-brain axis

Research over the past two decades has established a remarkable ability of the gut microbiota to modulate brain activity and behaviour. Conversely, signals from the brain can influence the composition and function of the gut microbiota. This bidirectional communication across the gut microbiota-brain axis, involving multiple biochemical and cellular mediators, is recognized as a major brain-body network that integrates cues from the environment and the body's internal state. Central to this network is the gut sensory system, formed by intimate connections between chemosensory epithelial cells and sensory nerve fibres, that conveys interoceptive signals to the central nervous system. In this Review, we provide a broad overview of the pathways that connect the gut and the brain, and explore the complex dialogue between microorganisms and neurons at this emerging intestinal neuroepithelial interface. We highlight relevant microbial factors, endocrine cells and neural mechanisms that govern gut microbiota-brain interactions and their implications for gastrointestinal and neuropsychiatric health.