Effects of Probiotic Supplementation on Gastrointestinal, Sensory and Core Symptoms in Autism Spectrum Disorders: A Randomized Controlled Trial

Embryonic exposure to 6:2 fluorotelomer alcohol mediates autism spectrum disorder-like behavior by dysfunctional microbe-gut-brain axis in mice

6:2 fluorotelomer alcohol (6:2 FTOH) is considered an emerging contaminant as a substitute for perfluoroalkyl and polyfluoroalkyl substances. Autism spectrum disorder (ASD) is a highly heterogeneous childhood neurodevelopmental disorder, the prevalence of which has been significantly increasing globally, possibly due to rising exposure to environmental pollutants. Additionally, the microbe-gut-brain axis plays a crucial role in the development of ASD. The purpose of study was to investigate the impact of embryonic 6:2 FTOH exposure on neurological development in mice and explore the potential involvement of the microbe-gut-brain. Pregnant mice were orally administered 6:2 FTOH from gestation day 8.5 until delivery, and follow-up testing was performed on day 22 post-delivery. The findings revealed that embryonic exposure to 6:2 FTOH led to ASD-like symptoms, cortical neuron apoptosis, glial cell activation, and abnormal synapse formation in mice. Furthermore, impairment of colonic barrier function, inflammatory response, and dysbiosis in gut microbiota were observed. Interestingly, supplementation with Lactobacillus rhamnosus GG during embryonic development mitigated these adverse outcomes. This study enhances our understanding of how environmental pollutants can impact neurological development in children and provides valuable insights for clinical prevention, diagnosis, and treatment strategies for non-genetic ASD.

Probiotics in autism spectrum disorders: a systematic review of clinical studies and future directions

CONTEXT

It is hypothesized that gut dysbiosis, a typical feature of patients with autism spectrum disorder (ASD), could be involved in the origin of this neurodevelopmental disorder. Therefore, the use of probiotics to restore gastrointestinal (GI) equilibrium might be a promising therapeutic strategy due to its capacity to balance the gut-brain axis and behavioral responses.

OBJECTIVE

To summarize current knowledge on the use of probiotics to treat core clinical ASD symptoms and concomitant GI signs, compare the design of published studies with those of ongoing trials, assess the near future of this field, and provide recommendations for improving novel studies.

DATA SOURCES

The literature search was conducted in February 2020 and updated in March 2021, using a broad range of bibliographic and clinical trial-specific databases.

DATA EXTRACTION

Data were extracted using a standardized form, and articles reporting on 28 clinical studies (already published or still ongoing) were included. The risk of bias in clinical studies was evaluated using the Cochrane Collaboration Risk of Bias Assessment tool for randomized trials and the Risk of Bias in Nonrandomized Studies-Interventions tool for nonrandomized trials.

RESULTS

The results suggest that probiotics improve ASD-like social deficits, GI symptoms, and gut microbiota profile. However, inconsistencies among studies and their methodological limitations make it difficult to draw any conclusions regarding the efficacy of probiotics in ASD. This review provides specific suggestions for future research to improve the quality of the studies.

CONCLUSIONS

Although ongoing studies have improved designs, the available knowledge does not permit solid conclusions to be made regarding the efficacy of probiotics in ameliorating the symptoms (psychiatric and/or GI) associated with ASD. Thus, more high-quality research and new approaches are needed to design effective probiotic strategies for ASD.

Should we consider microbiota-based interventions as a novel therapeutic strategy for schizophrenia? A systematic review and meta-analysis

Schizophrenia is a chronic psychiatric disorder characterized by a variety of symptoms broadly categorized into positive, negative, and cognitive domains. Its etiology is multifactorial, involving a complex interplay of genetic, neurobiological, and environmental factors, and its neurobiology is associated with abnormalities in different neurotransmitter systems. Due to this multifactorial etiology and neurobiology, leading to a wide heterogeneity of symptoms and clinical presentations, current antipsychotic treatments face challenges, underscoring the need for novel therapeutic approaches. Recent studies have revealed differences in the gut microbiome of individuals with schizophrenia compared to healthy controls, establishing an intricate link between this disorder and gastrointestinal health, and suggesting that microbiota-targeted interventions could help alleviate clinical symptoms. Therefore, this meta-analysis investigates whether gut microbiota manipulation can ameliorate psychotic outcomes in patients with schizophrenia receiving pharmacological treatment. Nine studies (n = 417 participants) were selected from 81 records, comprising seven randomized controlled trials and two open-label studies, all with a low risk of bias, included in this systematic review and meta-analysis. The overall combined effect size indicated significant symptom improvement following microbiota treatment (Hedges' g = 0.48, 95% CI = 0.09 to 0.88, p = 0.004, I2 = 62.35%). However, according to Hedges' g criteria, the effect size was small (approaching moderate), and study heterogeneity was moderate based on I2 criteria. This review also discusses clinical and preclinical studies to elucidate the neural, immune, and metabolic pathways by which microbiota manipulation, particularly with Lactobacillus and Bifidobacterium genera, may exert beneficial effects on schizophrenia symptoms via the gut-brain axis. Finally, we address the main confounding factors identified in our systematic review, highlight key limitations, and offer recommendations to guide future high-quality trials with larger participant cohorts to explore microbiome-based therapies as a primary or adjunctive treatment for schizophrenia.

Therapeutic effects of probiotics on symptoms of irritability/emotional lability associated with neurodevelopmental conditions: A systematic review and meta-analysis of placebo-controlled trials

OBJECTIVES

The current study aimed at investigating the efficacies of probiotics in alleviating the symptoms of irritability/emotional lability in individuals with a neurodevelopmental condition.

METHODS

Randomized placebo-controlled trials were identified through searching major electronic databases from inception to December, 2023. The outcome of interests included improvements in the symptoms of irritability/emotional lability. Outcomes were quantitatively expressed as effect size (ES) based on standardized mean difference (SMD) with 95 % confidence interval (CI).

RESULTS

Seven studies with 1479 participants were included in this meta-analysis. The primary results revealed a significant improvement in the symptoms of irritability/emotional lability in individuals with neurodevelopmental conditions receiving probiotics compared with the placebos (SMD= -0.17, p = 0.03). Subgroup analyses demonstrated an association between a significant improvement in the symptoms of irritability/emotional lability and the use probiotics relative to placebos only in studies using multiple-strain probiotics (SMD=-0.19, p = 0.04, three studies with 452 participant) but not in those adopting single-strain regimens.

CONCLUSIONS

Our study supported the use of probiotics for alleviating the symptoms of irritability/emotional lability in individuals with neurodevelopmental conditions, mainly in those receiving multiple-strain probiotics as supplements. Nevertheless, the limited number of studies targeting irritability as their primary outcomes, and most did not investigate other confounding factors such as dietary habits or consumption of other nutritional supplements may impair the robustness of evidence. Our results, which were derived from a limited number of available trials, warrant further large-scale clinical investigations for verification.

Effect of Probiotics on the Symptomatology of Autism Spectrum Disorder and/or Attention Deficit/Hyperactivity Disorder in Children and Adolescents: Pilot Study

The aim of this study is to investigate the impact of using probiotics with strains related to dopamine and gamma-aminobutyric acid production on clinical features of autism spectrum disorder (ASD) and/or attention deficit/hyperactivity disorder (ADHD). This randomized, controlled trial involved 38 children with ADHD and 42 children with ASD, aged 5-16 years, who received probiotics (Lactiplantibacillus plantarum and Levilactobacillus brevis 109/cfu/daily) or placebo for 12 weeks. Parent-reported symptoms were assessed using Conners' 3rd-Ed and the Social Responsiveness Scale Test, 2nd-Ed (SRS-2), and children completed the Conners Continuous Performance Test, 3rd-Ed (CPT 3) or Conners Kiddie CPT, 2nd-Ed (K-CPT 2). Executive functions, quality of life and sleep patterns were also parent-assessed. Intention-to-treat analyses, controlling for sociodemographic and nutritional covariates, revealed no significant inter-group differences in parent-reported or neuropsychological data after the probiotic intervention. However, age-stratified analyses showed improved hyperactivity-impulsivity symptoms in younger children with ASD (Cohen's d = 1.245) and ADHD (Cohen's d = 0.692). Intra-group analyses supported these findings in the aforementioned age and intervention group for both diagnoses. An improvement in impulsivity for children with ASD was also observed in the intra-group analysis of the CPT commissions scores (probiotic: p = 0.001, Cohen's d = -1.216; placebo: p = 0.013, Cohen's d = -0.721). A better comfort score (quality of life) was shown in children with ASD (probiotic: p = 0.010, Cohen's d = 0.722; placebo: p = 0.099, Cohen's d = 0.456). The probiotics used, may improve hyperactivity-impulsivity in children with ASD or/and ADHD and quality of life in children with ASD. Further research is warranted to explore probiotics as an adjunctive therapeutic intervention for NDs.Trial registration: clinicaltrials.gov Identifier: NCT05167110.

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.

IUPHAR review: Targeted therapies of signaling pathways based on the gut microbiome in autism spectrum disorders: Mechanistic and therapeutic applications

Autism spectrum disorders (ASD) are complex neurodevelopmental disorders characterized by impairments in social interaction, communication and repetitive activities. Gut microbiota significantly influences behavior and neurodevelopment by regulating the gut-brain axis. This review explores gut microbiota-influenced treatments for ASD, focusing on their therapeutic applications and mechanistic insights. In addition, this review discusses the interactions between gut microbiota and the immune, metabolic and neuroendocrine systems, focusing on crucial microbial metabolites including short-chain fatty acids (SCFAs) and several neurotransmitters. Furthermore, the review explores various therapy methods including fecal microbiota transplantation, dietary modifications, probiotics and prebiotics and evaluates their safety and efficacy in reducing ASD symptoms. The discussion shows the potential of customized microbiome-based therapeutics and the integration of multi-omics methods to understand the underlying mechanisms. Moreover, the review explores the intricate relationship between gut microbiota and ASD, aiming to develop innovative therapies that utilize the gut microbiome to improve the clinical outcomes of ASD patients. Microbial metabolites such as neurotransmitter precursors, tryptophan metabolites and SCFAs affect brain development and behavior. Symptoms of ASD are linked to changes in these metabolites. Dysbiosis in the gut microbiome may impact neuroinflammatory processes linked to autism, negatively affecting immune signaling pathways. Research indicates that probiotics and prebiotics can improve gut microbiota and alleviate symptoms in ASD patients. Fecal microbiota transplantation may also improve behavioral symptoms and restore gut microbiota balance. The review emphasizes the need for further research on gut microbiota modification as a potential therapeutic approach for ASD, highlighting its potential in clinical settings.

Alterations of oral microbiota in young children with autism: Unraveling potential biomarkers for early detection

OBJECTIVES

This study investigated the oral microbiota in young children with autism spectrum disorder (ASD) to determine possible alterations in microbial composition and identify potential biomarkers for early detection.

METHODS

Dental plaque samples from 25 children with ASD (aged 3-6 years; M = 4.79, SD = 0.83) and 30 age- and sex-matched typically developing (TD) children were analyzed using 16S rRNA sequencing.

RESULTS

The results showed lower bacterial diversity in children with ASD compared to controls, with distinct microbial compositions in the ASD and TD groups. Six discriminatory species (Microbacterium flavescens, Leptotrichia sp. HMT-212, Prevotella jejuni, Capnocytophaga leadbetteri, Leptotrichia sp. HMT-392, and Porphyromonas sp. HMT-278) were identified in the oral microbiota of ASD children, while five discriminatory species (Fusobacterium nucleatum subsp. polymorphum, Schaalia sp. HMT-180, Leptotrichia sp. HMT-498, Actinomyces gerencseriae, and Campylobacter concisus) were identified in TD controls. A model generated by random forest and leave-one-out cross-validation achieved an accuracy of 0.813. Receiver operating characteristic analysis yielded a sensitivity of 0.778, a specificity of 0.857, and an AUC (area under curve) of 0.937 (95 % CI: 0.82 - 1.00) for differentiating children with and without ASD.

CONCLUSION

The present study has unveiled significant disparities in the oral microbial composition between ASD and TD children.

SIGNIFICANCE

These findings contribute to understanding the microbiome-brain connection in ASD and its implications for early detection and management. Further research is needed to validate these oral bacterial biomarkers and explore their mechanistic association with ASD pathophysiology.

The therapeutic effects of probiotics on core and associated behavioral symptoms of autism spectrum disorders: a systematic review and meta-analysis

BACKGROUND

We aimed at investigating the efficacies of probiotics in alleviating the core and associated symptoms of autism spectrum disorder (ASD).

METHODS

Randomized placebo-controlled trials were identified from major electronic databases from inception to Nov 2023. The outcomes of interests including improvements in the total and associated symptoms of ASD were quantitatively expressed as effect size (ES) based on standardized mean difference (SMD) with 95% confidence interval (CI).

RESULTS

Ten studies with 522 participants (mean age = 8.11) were included in this meta-analysis. The primary results revealed significant improvement in total symptoms in the probiotics group compared with the controls (SMD = - 0.19, p = 0.03, ten studies, n = 522) but not the core symptoms (i.e., repetitive restricted behaviors, As affiliations 3 and 5 are same, we have deleted the duplicate affiliations and renumbered accordingly. Please check and confirm.problems with social behaviors/communication). Subgroup analyses demonstrated improvement in total symptoms in probiotics users relative to their controls only in studies using multiple-strain probiotics (SMD = - 0.26, p = 0.03, five studies, n = 288) but not studies using single-strain regimens. Secondary results showed improvement in adaptation (SMD = 0.37, p = 0.03, three studies, n = 139) and an improvement trend in anxiety symptoms in the probiotics group compared with controls (SMD = - 0.29, 95% CI - 0.60 to 0.02, p = 0.07, three studies, n = 163) but failed to demonstrate greater improvement in the former regarding symptoms of irritability/aggression, hyperactivity/impulsivity, inattention, and parental stress.

CONCLUSIONS

Our study supported probiotics use against the overall behavioral symptoms of ASD, mainly in individuals receiving multiple-strain probiotics as supplements. However, our results showed that probiotics use was only associated with improvement in adaptation and perhaps anxiety, but not core symptoms, highlighting the impact of adaptation on quality of life rather than just the core symptoms. Nevertheless, the limited number of included trials warrants further large-scale clinical investigations.

An Update on Microbial Interventions in Autism Spectrum Disorder with Gastrointestinal Symptoms

In the United States, autism spectrum disorder (ASD) affects 1 in 33 children and is characterized by atypical social interactions, communication difficulties, and intense, restricted interests. Microbial dysbiosis in the gastrointestinal (GI) tract is frequently observed in individuals with ASD, potentially contributing to behavioral manifestations and correlating with worsening severity. Moreover, dysbiosis may contribute to the increased prevalence of GI comorbidities in the ASD population and exacerbate immune dysregulation, further worsening dysbiosis. Over the past 25 years, research on the impact of microbial manipulation on ASD outcomes has gained substantial interest. Various approaches to microbial manipulation have been preclinically and clinically tested, including antibiotic treatment, dietary modifications, prebiotics, probiotics, and fecal microbiota transplantation. Each method has shown varying degrees of success in reducing the severity of ASD behaviors and/or GI symptoms and varying long-term efficacy. In this review, we discuss these microbiome manipulation methods and their outcomes. We also discuss potential microbiome manipulation early in life, as this is a critical period for neurodevelopment.

Relationship between frequency of yogurt consumption at 1 year of age and development at 3 years of age: The Japan Environment and Children's Study

BACKGROUND

Multiple observational studies have demonstrated the health benefits of yogurt, which are considered due to yogurt's positive effects on the gut microbiota. It is also known that the intestinal microbiota is associated with cognitive and emotional functions. Although the intake of probiotics has been reported to improve neurodevelopmental symptoms in children, no large-scale studies have examined the association of yogurt consumption in early childhood with later neurodevelopmental status. In this study, we examined the association between frequency of such consumption at 1 year of age and the children's subsequent neurodevelopmental status.

METHODS

We studied children's dietary consumption of yogurt at age 1 year and their neurodevelopment at age 3 years from data gathered from70,276 mother-child pairs enrolled in the Japan Environment and Children's Study. We collected data from pregnant women whose consent was obtained after the study was explained to them at participating facilities in the target area. Frequency of yogurt consumption was categorized into 0, 1-2, 3-4, and ≥ 5 times/week based on a questionnaire about the child's diet completed by the mother. Developmental delay was assessed using the Ages and Stages Questionnaires, Third Edition (ASQ-3™) in five domains: communication, gross motor, fine motor, problem solving, and personal-social. Using the results of the group that did not consume yogurt as a reference, multivariate logistic regression analysis was performed to compare the neurodevelopment of children according to frequency of yogurt consumption. For the covariates, items related to the socio-economic background and children's neurodevelopment were selected with reference to previous studies.

RESULTS

Consumption of yogurt 1-4 times/week was associated with a reduced risk of developmental delay in all ASQ-3 categories(adjusted odds ratios, 0.71-0.87). However, the risk of developmental delay was not necessarily reduced with yogurt consumption ≥5 times/week (adjusted odds ratios, 0.84-0.96).

CONCLUSION

Yogurt consumption habits at 1 year of age were associated with a lower risk of developmental delay at 3 years of age. However, the association was less apparent when yogurt was consumed more frequently. Possible mechanisms by which yogurt intake affects neurodevelopment include neurotransmitters produced by intestinal bacteria as well as the suppression of intestinal inflammation through improvements in the intestinal environment. Regular intake of yogurt in early childhood may have a positive association with neurodevelopment, but it is hoped that clearer links will be found in the future through intervention studies.

The Microbiome-Genetics Axis in Autism Spectrum Disorders: A Probiotic Perspective

Autism spectrum disorder (commonly known as autism) is a complex and prevalent neurodevelopmental condition characterized by challenges in social behavior, restricted interests, and repetitive behaviors. It is projected that the annual cost of autism spectrum disorder in the US will reach USD 461 billion by 2025. However, despite being a major public health problem, effective treatment for the underlying symptoms remains elusive. As numerous literature data indicate the role of gut microbiota in autism prognosis, particularly in terms of alleviating gastrointestinal (GI) symptoms, high hopes have been placed on probiotics for autism treatment. Approximately twenty clinical studies have been conducted using single or mixed probiotic cultures. However, unequivocal results on the effect of probiotics on people with autism have not been obtained. The small sample sizes, differences in age of participants, choice of probiotics, dose and duration of treatment, outcome measures, and analytical methods used are largely inconsistent, making it challenging to draw distinctive conclusions. Here, we discuss the experimental evidence for specific gut bacteria and their metabolites and how they affect autism in light of the phenotypic and etiological complexity and heterogeneity. We propose a personalized medicine approach for using probiotics to increase the quality of life of individuals with autism by selecting specific probiotics to improve particular features of the condition.

Investigating brain-gut microbiota dynamics and inflammatory processes in an autistic-like rat model using MRI biomarkers during childhood and adolescence

Autism spectrum disorder (ASD) is characterized by social interaction deficits and repetitive behaviors. Recent research has linked that gut dysbiosis may contribute to ASD-like behaviors. However, the exact developmental time point at which gut microbiota alterations affect brain function and behavior in patients with ASD remains unclear. We hypothesized that ASD-related brain microstructural changes and gut dysbiosis induce metabolic dysregulation and proinflammatory responses, which collectively contribute to the social behavioral deficits observed in early childhood. We used an autistic-like rat model that was generated via prenatal valproic acid exposure. We analyzed brain microstructural changes using diffusion tensor imaging (DTI) and examined microbiota, blood, and fecal samples for inflammation biomarkers. The ASD model rats exhibited significant brain microstructural changes in the anterior cingulate cortex, hippocampus, striatum, and thalamus; reduced microbiota diversity (Prevotellaceae and Peptostreptococcaceae); and altered metabolic signatures. The shift in microbiota diversity and density observed at postnatal day (PND) 35, which is a critical developmental period, underscored the importance of early ASD interventions. We identified a unique metabolic signature in the ASD model, with elevated formate and reduced acetate and butyrate levels, indicating a dysregulation in short-chain fatty acid (SCFA) metabolism. Furthermore, increased astrocytic and microglial activation and elevated proinflammatory cytokines-interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α)-were observed, indicating immune dysregulation. This study provided insights into the complex interplay between the brain and the gut, and indicated DTI metrics as potential imaging-based biomarkers in ASD, thus emphasizing the need for early childhood interventions.

Probiotics for autism spectrum disorder: An updated systematic review and meta-analysis of effects on symptoms

BACKGROUND

Recent researches highlighted the significant role of the gut-brain axis and gut microbiota in autism spectrum disorder (ASD), a neurobehavioral developmental disorder characterized by a variety of neuropsychiatric and gastrointestinal symptoms, suggesting that alterations in the gut microbiota may correlate with the severity of ASD symptoms. Therefore, this study was designed to conduct a comprehensive systematic review and meta-analysis of the effectiveness of probiotic interventions in ameliorating behavioral symptoms in individuals with ASD.

METHODS

This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. A comprehensive literature search was performed across multiple databases including the Cochrane Library, PubMed, Web of Science, and Google Scholar up until June 2024. Inclusion criteria encompassed published randomized clinical trials (RCTs), focusing on probiotic interventions and evaluating outcomes related to ASD behavior symptoms. The study utilized Cochrane's Risk of Bias 2 for bias assessment and applied random effect models with inverse variance method for statistical analysis, also addressing publication bias and conducting subgroup analyses through Begg's and Egger's tests to explore the effects of various factors on the outcomes.

RESULTS

Our meta-analysis, which looked at eight studies with a total of 318 samples from ASD patients aged 1.5-20 years, showed that the probiotic intervention group had significantly better behavioral symptoms compared to the control group. This was shown by a pooled standardized mean difference (SMD) of -0.38 (95% CI: 0.58 to -0.18, p < 0.01). Subgroup analyses revealed significant findings across a variety of factors: studies conducted in the European region showed a notable improvement with an SMD of -0.44 (95%CI: 0.72 to -0.15); interventions lasting longer than three months exhibited a significant improvement with an SMD of -0.43 (95%CI: 0.65 to -0.21); and studies focusing on both participants under and greater than 10 years found significant benefits with an SMDs of -0.37 and -0.40, respectively (95%CI: 0.65 to -0.09, and 95%CI: 0.69 to -0.11, respectively). Moreover, both multi-strain probiotics and single-strain interventions showed an overall significant improvement with a SMD of -0.53 (95%CI: 0.85 to -0.22) and -0.28 (95%CI: 0.54 to -0.02), respectively. Also, the analysis confirmed the low likelihood of publication bias and the robustness of these findings.

CONCLUSION

Our study highlighted the significant improvement in ASD behavioral symptoms through probiotic supplementation. The need for personalized treatment approaches and further research to confirm efficacy and safety of probiotics in ASD management is emphasized.

Unraveling the relative abundance of psychobiotic bacteria in children with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by social deficits. Accumulated evidence has shown a link between alterations in the composition of gut microbiota and both neurobehavioural and gastrointestinal symptoms in children with ASD which are related to the genera Lactobacillus and Bifidobacterium. These genera have been recently categorized as "psychobiotics". Moreover, this study aimed to compare the relative abundance of psychobiotics (L. plantarum, L. reuteri, and B. longum) to the total gut microbiome in typically developing (TD) children and those with ASD in order to correlate the distribution of psychobiotic with the severity and sensory impairments in autism. The ASD children were assessed using the Childhood Autism Rating Scale (CARS), while sensory impairments were evaluated using the Short Sensory Profile (SSP). Furthermore, the gut microbiome was analyzed using the quantitative real-time PCR. The study revealed a statistically significant increase in the relative abundance of L. reuteri and L. plantarum in the TD group in comparison to ASD children. Regarding the SSP total score of ASD children, a statistically significant negative correlation was found between both Lactobacillus and L. plantarum with the under-responsive subscale. For the Autism Treatment Evaluation Checklist (ATEC) score, B. longum and Lactobacillus showed a significant positive correlation with Health/Physical/Behaviour.

Gastrointestinal, Behaviour and Anxiety Outcomes in Autistic Children Following an Open Label, Randomised Pilot Study of Synbiotics vs Synbiotics and Gut-Directed Hypnotherapy

Alterations of the microbiome-gut-brain (MGB) axis have been associated with autism spectrum disorder (ASD) and disorders of gut-brain interaction (DGBI). DGBI are highly prevalent in autistic children and are associated with worsening behaviour and anxiety. Treatments such as probiotics, prebiotics and gut-directed hypnotherapy (GDH) have shown efficacy in improving gut symptoms in children. The primary objective of the study was to compare changes in gastrointestinal (GI) scores following a 12-week intervention of synbiotics (prebiotic + probiotic) +/- GDH with a follow-up at 24 weeks. Secondary objectives included changes in behavioural and anxiety symptoms, while changes in gut microbiome composition were assessed as an exploratory objective. Children diagnosed with ASD aged 5.00-10.99 years (n = 40) were recruited and randomised (1:1) to a 12-week intervention of either synbiotics (SYN group) or synbiotics + GDH (COM group). Both the SYN and COM group experienced significant reductions in total GI scores post-intervention and at follow-up (p < 0.001), with no superiority of the COM treatment over the SYN treatment. The COM group showed beneficial reductions in anxiety scores (p = 0.002) and irritability behaviours (p < 0.001) which were not present in the SYN group. At follow-up, only those in the COM group maintained significant reductions in GI pain scores (p < 0.001). There were significant changes in gut microbiota such as increases in Bifidobacterium animalis and Dialister in both groups over time. In conclusion, synbiotics with or without GDH may help support standard care for autistic children who suffer comorbid DGBI. The trial was prospectively registered at clinicialtrials.gov on 16 November 2020 (NCTO4639141).

The impact of probiotics on core autism symptoms - A systematic review and meta-analysis of randomized clinical trials

BACKGROUND & AIMS

Studies have shown evidence of gut dysbiosis in individuals with autism spectrum disorder (ASD). Various microbiome-modifying treatments, including probiotics, have been proposed. This review systematically assessed the evidence on the effects of probiotics on core autism symptoms in children with ASD.

METHODS

We performed a comprehensive literature search in Medline, Embase, CENTRAL, PsycInfo, and clinical trial registries, up to March 2023, and updated on January 10, 2024. Randomized controlled trials (RCTs) of parallel-group and cross-over designs were eligible. The population included individuals below 20 years of age diagnosed with ASD. Trials evaluating the effects of probiotics (any strain or dose) compared to placebo, no treatment, or another intervention were included. The outcomes of interest included the core autism symptoms: deficits in social skills, communication skills, and restricted, repetitive behaviors. No language restrictions were applied. Studies were excluded if an additional active compound was administered. The risk of bias was assessed using the Revised Cochrane Risk of Bias tool (RoB 2). This review was registered in PROSPERO (CRD42023393000).

RESULTS

In total, 12 RCTs assessing 630 participants were included. A borderline significant beneficial effect of probiotics on core ASD symptoms was found (8 RCTs, mean difference -0.21; 95% CI -0.39 to -0.03). Subgroup analysis according to study type showed a significant positive effect in parallel group trials (6 RCTs, mean difference -0.26; 95% CI -0.48 to -0.05). The pooled effect estimates for the other outcomes didn't reveal significant differences between the groups. Importantly, the risk of bias was high in nine studies.

CONCLUSIONS

Available data do not provide high-quality evidence supporting the use of probiotics for ASD symptoms in children.

Cutting-Edge iPSC-Based Approaches in Studying Host-Microbe Interactions in Neuropsychiatric Disorders

Gut microbiota (GM), together with its metabolites (such as SCFA, tryptophan, dopamine, GABA, etc.), plays an important role in the functioning of the central nervous system. Various neurological and psychiatric disorders are associated with changes in the composition of GM and their metabolites, which puts them in the foreground as a potential adjuvant therapy. However, the molecular mechanisms behind this relationship are not clear enough. Therefore, before considering beneficial microbes and/or their metabolites as potential therapeutics for brain disorders, the mechanisms underlying microbiota-host interactions must be identified and characterized in detail. In this review, we summarize the current knowledge of GM alterations observed in prevalent neurological and psychiatric disorders, multiple sclerosis, major depressive disorder, Alzheimer's disease, and autism spectrum disorders, together with experimental evidence of their potential to improve patients' quality of life. We further discuss the main obstacles in the study of GM-host interactions and describe the state-of-the-art solution and trends in this field, namely "culturomics" which enables the culture and identification of novel bacteria that inhabit the human gut, and models of the gut and blood-brain barrier as well as the gut-brain axis based on induced pluripotent stem cells (iPSCs) and iPSC derivatives, thus pursuing a personalized medicine agenda for neuropsychiatric disorders.

Impact of Human Milk Oligosaccharides and Probiotics on Gut Microbiome and Mood in Autism: A Case Report

Recent evidence has highlighted the role of the gut-brain axis in the progression of autism spectrum disorder (ASD), with significant changes in the gut microbiome of individuals with this condition. This report investigates the effects of probiotics and human milk oligosaccharide (HMO) supplements on the gut microbiome, inflammatory cytokine profile, and clinical outcomes in an ASD adolescent with chronic gastrointestinal dysfunction and cognitive impairment. Following treatment, we observed a decrease in proinflammatory cytokines' concentration alongside Sutterella relative abundance, a bacterium reported to be linked with gastrointestinal diseases. Also, we reported a notable increase in mood stability. The study aims to evaluate the use of gut microbiome-based therapy in selected ASD patients, highlighting its potential to improve related clinical symptoms.

Gut Microbiota and Autism Spectrum Disorder: A Neuroinflammatory Mediated Mechanism of Pathogenesis?

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in social communication and behavior, frequently accompanied by restricted and repetitive patterns of interests or activities. The gut microbiota has been implicated in the etiology of ASD due to its impact on the bidirectional communication pathway known as the gut-brain axis. However, the precise involvement of the gut microbiota in the causation of ASD is unclear. This study critically examines recent evidence to rationalize a probable mechanism in which gut microbiota symbiosis can induce neuroinflammation through intermediator cytokines and metabolites. To develop ASD, loss of the integrity of the intestinal barrier, activation of microglia, and dysregulation of neurotransmitters are caused by neural inflammatory factors. It has emphasized the potential role of neuroinflammatory intermediates linked to gut microbiota alterations in individuals with ASD. Specifically, cytokines like brain-derived neurotrophic factor, calprotectin, eotaxin, and some metabolites and microRNAs have been considered etiological biomarkers. We have also overviewed how probiotic trials may be used as a therapeutic strategy in ASD to reestablish a healthy balance in the gut microbiota. Evidence indicates neuroinflammation induced by dysregulated gut microbiota in ASD, yet there is little clarity based on analysis of the circulating immune profile. It deems the repair of microbiota load would lower inflammatory chaos in the GI tract, correct neuroinflammatory mediators, and modulate the neurotransmitters to attenuate autism. The interaction between the gut and the brain, along with alterations in microbiota and neuroinflammatory biomarkers, serves as a foundational background for understanding the etiology, diagnosis, prognosis, and treatment of autism spectrum disorder.

Harnessing the Gut Microbiome: To What Extent Can Pre-/Probiotics Alleviate Immune Activation in Autism Spectrum Disorder?

Children diagnosed with autism spectrum disorder (ASD) are at an increased risk of experiencing gastrointestinal (GI) discomfort, which has been linked to dysfunctions in the microbiome-gut-brain axis. The bidirectional communication between gut and brain plays a crucial role in the overall health of individuals, and alterations in the gut microbiome can contribute to immune activation and gut-brain dysfunction in ASD. Despite the limited and controversial results of pre-/probiotic applications in ASD, this review comprehensively maps the association between ASD clinical symptoms and specific bacterial taxa and evaluates the efficacy of pre-/probiotics in modulating microbiota composition, reducing inflammatory biomarkers, alleviating difficulties in GI distress, sleep problems, core and other ASD-associated symptoms, as well as relieving parental concerns, separately, in individuals with ASD. Beyond simply targeting core ASD symptoms, this review highlights the potential of pre-/probiotic supplementations as a strategy to modulate gut homeostasis and immune response, and to delineate the potential mechanisms by which its direct or mediating effects can alleviate gut-brain dysfunction and poor nutritional status in ASD management. Further well-designed randomized controlled trials are needed to strengthen the existing evidence and establish optimal protocols for the use of pre-/probiotics in the context of ASD.

Effect of probiotics on children with autism spectrum disorders: a meta-analysis

BACKGROUND

Researches have found that alteration of intestinal flora may be closely related to the development of autism spectrum disorder (ASD). However, whether probiotics supplementation has a protective effect on ASD remains controversial. This meta-analysis aimed to analyze the outcome of probiotics in the treatment of ASD children.

METHODS

The Pubmed, Cochrane Library, Web of Science and Embase were searched until Sep 2022. Randomized controlled trials (RCTs) relevant to the probiotics and placebo treatment on ASD children were screened. Quality assessment of the included RCTs was evaluated by the Cochrane collaboration's tool. The primary outcomes were ASD assessment scales, including ABC (aberrant behavior checklist) and CBCL (child behavior checklist) for evaluating the behavior improvement, SRS (social responsiveness scale) for social assessment, DQ (developmental quotient) for physical and mental development and CGI-I (clinical global impression improvement) for overall improvement. The secondary outcome was total 6-GSI (gastrointestinal severity index).

RESULTS

In total, 6 RCTs from 6 studies with 302 children were included in the systemic review. Total 6-GSI (MD=-0.59, 95%CI [-1.02,-0.17], P < 0.05) decreased significantly after oral administration of probiotics. Whereas, there was no statistical difference in ABC, CBCL, SRS, DQ and CGI-I between probiotics and placebo groups in ASD children.

CONCLUSION

Probiotics treatment could improve gastrointestinal symptoms, but there was no significant improvement in ASD.

Dietary flavonoids modulate the gut microbiota: A new perspective on improving autism spectrum disorder through the gut-brain axis

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with an unknown etiology. It is associated with various factors and causes great inconvenience to the patient's life. The gut-brain axis (GBA), which serves as a bidirectional information channel for exchanging information between the gut microbiota and the brain, is vital in studying many neurodegenerative diseases. Dietary flavonoids provide anti-inflammatory and antioxidant benefits, as well as regulating the structure and function of the gut microbiota. The occurrence and development of ASD are associated with dysbiosis of the gut microbiota. Modulation of gut microbiota can effectively improve the severity of ASD. This paper reviews the links between gut microbiota, flavonoids, and ASD, focusing on the mechanism of dietary flavonoids in regulating ASD through the GBA.

Precision synbiotics increase gut microbiome diversity and improve gastrointestinal symptoms in a pilot open-label study for autism spectrum disorder

The efficacy of prebiotics and probiotics (synbiotics when combined) to improve symptoms associated with autism spectrum disorder (ASD) has shown considerable inter-study variation, likely due to the complex, heterogeneous nature of the disorder and its associated behavioral, developmental, and gastrointestinal symptoms. Here, we present a precision synbiotic supplementation study in 296 children and adults diagnosed with ASD versus 123 age-matched neurotypical controls. One hundred seventy ASD participants completed the study. Baseline and post-synbiotic assessment of ASD and gastrointestinal (GI) symptoms and deep metagenomic sequencing were performed. Within the ASD cohort, there were significant differences in microbes between subpopulations based on the social responsiveness scale (SRS2) survey (Prevotella spp., Bacteroides, Fusicatenibacter, and others) and gluten and dairy-free diets (Bifidobacterium spp., Lactococcus, Streptococcus spp., and others). At the baseline, the ASD cohort maintained a lower taxonomic alpha diversity and significant differences in taxonomic composition, metabolic pathways, and gene families, with a greater proportion of potential pathogens, including Shigella, Klebsiella, and Clostridium, and lower proportions of beneficial microbes, including Faecalibacterium compared to controls. Following the 3-month synbiotic supplementation, the ASD cohort showed increased taxonomic alpha diversity, shifts in taxonomy and metabolic pathway potential, and improvements in some ASD-related symptoms, including a significant reduction in GI discomfort and overall improved language, comprehension, cognition, thinking, and speech. However, the open-label study design may include some placebo effects. In summary, we found that precision synbiotics modulated the gut microbiome and could be used as supplementation to improve gastrointestinal and ASD-related symptoms.

IMPORTANCE

Autism spectrum disorder (ASD) is prevalent in 1 out of 36 children in the United States and contributes to health, financial, and psychological burdens. Attempts to identify a gut microbiome signature of ASD have produced varied results. The limited pre-clinical and clinical population sizes have hampered the success of these trials. To understand the microbiome associated with ASD, we employed whole metagenomic shotgun sequencing to classify microbial composition and genetic functional potential. Despite being one of the most extensive ASD post-synbiotic assessment studies, the results highlight the complexity of performing such a case-control supplementation study in this population and the potential for a future therapeutic approach in ASD.

Autism spectrum disorders and the gastrointestinal tract: insights into mechanisms and clinical relevance

Autism spectrum disorders (ASDs) are recognized as central neurodevelopmental disorders diagnosed by impairments in social interactions, communication and repetitive behaviours. The recognition of ASD as a central nervous system (CNS)-mediated neurobehavioural disorder has led most of the research in ASD to be focused on the CNS. However, gastrointestinal function is also likely to be affected owing to the neural mechanistic nature of ASD and the nervous system in the gastrointestinal tract (enteric nervous system). Thus, it is unsurprising that gastrointestinal disorders, particularly constipation, diarrhoea and abdominal pain, are highly comorbid in individuals with ASD. Gastrointestinal problems have also been repeatedly associated with increased severity of the core symptoms diagnostic of ASD and other centrally mediated comorbid conditions, including psychiatric issues, irritability, rigid-compulsive behaviours and aggression. Despite the high prevalence of gastrointestinal dysfunction in ASD and its associated behavioural comorbidities, the specific links between these two conditions have not been clearly delineated, and current data linking ASD to gastrointestinal dysfunction have not been extensively reviewed. This Review outlines the established and emerging clinical and preclinical evidence that emphasizes the gut as a novel mechanistic and potential therapeutic target for individuals with ASD.

Existing and Future Strategies to Manipulate the Gut Microbiota With Diet as a Potential Adjuvant Treatment for Psychiatric Disorders

Nutrition and diet quality play key roles in preventing and slowing cognitive decline and have been linked to multiple brain disorders. This review compiles available evidence from preclinical studies and clinical trials on the impact of nutrition and interventions regarding major psychiatric conditions and some neurological disorders. We emphasize the potential role of diet-related microbiome alterations in these effects and highlight commonalities between various brain disorders related to the microbiome. Despite numerous studies shedding light on these findings, there are still gaps in our understanding due to the limited availability of definitive human trial data firmly establishing a causal link between a specific diet and microbially mediated brain functions and symptoms. The positive impact of certain diets on the microbiome and cognitive function is frequently ascribed with the anti-inflammatory effects of certain microbial metabolites or a reduction of proinflammatory microbial products. We also critically review recent research on pro- and prebiotics and nondietary interventions, particularly fecal microbiota transplantation. The recent focus on diet in relation to brain disorders could lead to improved treatment outcomes with combined dietary, pharmacological, and behavioral interventions.

A comparison between children and adolescents with autism spectrum disorders and healthy controls in biomedical factors, trace elements, and microbiota biomarkers: a meta-analysis

Introduction

Autism spectrum disorder (ASD) is a multifaceted developmental condition that commonly appears during early childhood. The etiology of ASD remains multifactorial and not yet fully understood. The identification of biomarkers may provide insights into the underlying mechanisms and pathophysiology of the disorder. The present study aimed to explore the causes of ASD by investigating the key biomedical markers, trace elements, and microbiota factors between children with autism spectrum disorder (ASD) and control subjects.

Methods

Medline, PubMed, ProQuest, EMBASE, Cochrane Library, PsycINFO, Web of Science, and EMBSCO databases have been searched for publications from 2012 to 2023 with no language restrictions using the population, intervention, control, and outcome (PICO) approach. Keywords including "autism spectrum disorder," "oxytocin," "GABA," "Serotonin," "CRP," "IL-6," "Fe," "Zn," "Cu," and "gut microbiota" were used for the search. The Joanna Briggs Institute (JBI) critical appraisal checklist was used to assess the article quality, and a random model was used to assess the mean difference and standardized difference between ASD and the control group in all biomedical markers, trace elements, and microbiota factors.

Results

From 76,217 records, 43 studies met the inclusion and exclusion criteria and were included in this meta-analysis. The pooled analyses showed that children with ASD had significantly lower levels of oxytocin (mean differences, MD = -45.691, 95% confidence interval, CI: -61.667, -29.717), iron (MD = -3.203, 95% CI: -4.891, -1.514), and zinc (MD = -6.707, 95% CI: -12.691, -0.722), lower relative abundance of Bifidobacterium (MD = -1.321, 95% CI: -2.403, -0.238) and Parabacteroides (MD = -0.081, 95% CI: -0.148, -0.013), higher levels of c-reactive protein, CRP (MD = 0.401, 95% CI: 0.036, 0.772), and GABA (MD = 0.115, 95% CI: 0.045, 0.186), and higher relative abundance of Bacteroides (MD = 1.386, 95% CI: 0.717, 2.055) and Clostridium (MD = 0.281, 95% CI: 0.035, 0.526) when compared with controls. The results of the overall analyses were stable after performing the sensitivity analyses. Additionally, no substantial publication bias was observed among the studies.

Interpretation

Children with ASD have significantly higher levels of CRP and GABA, lower levels of oxytocin, iron, and zinc, lower relative abundance of Bifidobacterium and Parabacteroides, and higher relative abundance of Faecalibacterium, Bacteroides, and Clostridium when compared with controls. These results suggest that these indicators may be a potential biomarker panel for the diagnosis or determining therapeutic targets of ASD. Furthermore, large, sample-based, and randomized controlled trials are needed to confirm these results.

Omic characterizing and targeting gut dysbiosis in children with autism spectrum disorder: symptom alleviation through combined probiotic and medium-carbohydrate diet intervention - a pilot study

Autism spectrum disorder (ASD) currently lacks effective diagnostic and therapeutic approaches. Disruptions in the gut ecosystem have been observed in individuals with ASD, suggesting that targeting gut microbiota through probiotic and dietary supplementation may serve as a potential treatment strategy. This two-phase study aimed to characterize the fecal metagenome of children with ASD and investigate the beneficial effects of a combined probiotic and medium-carbohydrate intervention in ASD. Fecal metagenomes of children with ASD were compared to those of typically developing children, revealing intestinal dysbiosis in ASD, characterized by reduced levels of Prevotella sp. Dialister invisus, and Bacteroides sp. along with increased predicted abundances of inosine, glutamate, xanthine, and methylxanthine. The gut bacteriome and phageome exhibited high cooperativity. In a 3-month pilot study, Bifidobacterium animalis subsp. lactis Probio-M8 (Probio-M8) was administered alongside a medium-carbohydrate diet to Chinese children with ASD. The primary endpoint was the Childhood Autism Rating Scale (CARS), while the secondary endpoint was the Gastrointestinal Symptom Rating Scale (GSRS). A total of 72 autistic children were initially recruited for the intervention study, but only 53 completed the intervention. Probio-M8, in combination with dietary intervention, significantly improved CARS and GSRS scores, increased fecal levels of Bifidobacterium animalis, Akkermansia muciniphila, Fusicatenibacter saccharivorans, and Sutterella sp. while also reducing Blautia obeum (Benjamini-Hochberg corrected p ≤ 0.05 for all cases). The intervention also modulated fecal metabolites associated with the metabolism of amino acids (lysine), neurotransmitters (glutamate, γ-aminobutyric acid), polyunsaturated fatty acids (arachidonate, myristic acid), and vitamin B3. In conclusion, Probio-M8 combined with medium-carbohydrate diet effectively improved ASD symptoms, with associated changes in the gut microbiome and metabolome, supporting its potential as an adjunctive therapy for ASD.

Neurodevelopmental and Neuropsychiatric Disorders

This chapter will focus on microglial involvement in neurodevelopmental and neuropsychiatric disorders, particularly autism spectrum disorder (ASD), schizophrenia and major depressive disorder (MDD). We will describe the neuroimmune risk factors that contribute to the etiopathology of these disorders across the lifespan, including both in early life and adulthood. Microglia, being the resident immune cells of the central nervous system, could play a key role in triggering and determining the outcome of these disorders. This chapter will review preclinical and clinical findings where microglial morphology and function were examined in the contexts of ASD, schizophrenia and MDD. Clinical evidence points out to altered microglial morphology and reactivity, as well as increased expression of pro-inflammatory cytokines, supporting the idea that microglial abnormalities are involved in these disorders. Indeed, animal models for these disorders found altered microglial morphology and homeostatic functions which resulted in behaviours related to these disorders. Additionally, as microglia have emerged as promising therapeutic targets, we will also address in this chapter therapies involving microglial mechanisms for the treatment of neurodevelopmental and neuropsychiatric disorders.

Probiotics, prebiotics, and synbiotics for patients with autism spectrum disorder: a meta-analysis and umbrella review

Background and objective

The potential impact of gut health on general physical and mental well-being, particularly in relation to brain function, has led to a growing interest in the potential health advantages of prebiotics, probiotics, and synbiotics for the management of ASD. A comprehensive meta-analysis and systematic review was conducted in order to evaluate the effectiveness and protection of many drugs targeted at manipulating the microbiota in the treatment of ASD.

Methods

The present study employed a comprehensive examination of various electronic databases yielded a total of 3,393 records that were deemed possibly pertinent to the study. RCTs encompassed a total of 720 individuals between the ages of 2 and 17, as well as 112 adults and participants ranging from 5 to 55 years old, all of whom had received a diagnosis of ASD.

Results

Overall, 10 studies reported Autism-Related Behavioral Symptoms (ARBS). Regarding the enhancement of autism-related behavioral symptoms, there wasn't a statistically significant difference between the intervention groups (combined standardized mean difference = -0.07, 95% confidence interval: -0.39 to 0.24, Z = 0.46, p = 0.65). We observed that in the patients with ASD treated with probiotic frontopolar's power decreased significantly from baseline to endpoints in beta band (Baseline: 13.09 ± 3.46, vs. endpoint: 10.75 ± 2.42, p = 0.043, respectively) and gamma band (Baseline: 5.80 ± 2.42, vs. endpoint: 4.63 ± 1.39, p = 0.033, respectively). Among all tested biochemical measures, a significant negative correlation was found between frontopolar coherence in the gamma band and TNF-α (r = -0.30, p = 0.04).

Conclusion

The existing body of research provides a comprehensive analysis of the developing evidence that indicates the potential of probiotics, prebiotics, and synbiotics as therapeutic therapies for ASD. Our findings revealed that those there was no significant effect of such therapy on autism-related behavioral symptoms, it has significant effect on the brain connectivity through frontopolar power in beta and gamma bands mediated by chemicals and cytokines, such as TNF-α. The psychobiotics showed no serious side-effects.

A Review of the Nutritional Approach and the Role of Dietary Components in Children with Autism Spectrum Disorders in Light of the Latest Scientific Research

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects several areas of mental development. The onset of ASD occurs in the first few years of life, usually before the age of 3 years. Proper nutrition is important to ensure that an individual's nutrient and energy requirements are met, and it can also have a moderating effect on the progression of the disorder. A systematic database search was conducted as a narrative review to determine whether nutrition and specific diets can potentially alter gastrointestinal symptoms and neurobehavioral disorders. Databases such as Science Direct, PubMed, Scopus, Web of Science (WoS), and Google Scholar were searched to find studies published between 2000 and September 2023 on the relationship between ASD, dietary approaches, and the role of dietary components. The review may indicate that despite extensive research into dietary interventions, there is a general lack of conclusive scientific data about the effect of therapeutic diets on ASD; therefore, no definitive recommendation can be made for any specific nutritional therapy as a standard treatment for ASD. An individualized dietary approach and the dietician's role in the therapeutic team are very important elements of every therapy. Parents and caregivers should work with nutrition specialists, such as registered dietitians or healthcare providers, to design meal plans for autistic individuals, especially those who would like to implement an elimination diet.

Expression of miRNAs in Pre-Schoolers with Autism Spectrum Disorders Compared with Typically Developing Peers and Its Effects after Probiotic Supplementation

Alteration of the microbiota-gut-brain axis has been recently recognized as a possible contributor to the physiopathology of autism spectrum disorder (ASD). In this context, microRNA (miRNAs) dysfunction, implicated both in several neuropathological conditions including ASD and in different gastrointestinal disorders (GIDs), could represent an important modulating factor. In this contextual framework, we studied the transcriptional profile of specific circulating miRNAs associated with both ASD (miR-197-5p, miR-424-5p, miR-500a-5p, miR-664a-5p) and GID (miR-21-5p, miR-320a-5p, miR-31-5p, miR-223-5p) in a group of pre-schoolers with ASD and in typically developing (TD) peers. In the ASD group, we also assessed the same miRNAs after a 6-month supplementation with probiotics and their correlation with plasma levels of zonulin and lactoferrin. At baseline, the expression of miRNAs involved in ASD were significantly reduced in ASD pre-schoolers vs. TD controls. Regarding the miRNAs involved in GID, the expression levels of miR-320-5p, miR-31-5p, and miR-223-5p were significantly higher in ASD than in TD subjects, whereas miR-21-5p showed significantly reduced expression in the ASD group vs. TD group. Supplementation with probiotics did not significantly change the expression of miRNAs in the ASD population. We found a significative negative correlation between zonulin and miR-197-5p and miR-21-5p at baseline, as well as between lactoferrin and miR-223-5p after 6 months of probiotic supplementation. Our study confirms the presence of an altered profile of the miRNAs investigated in ASD versus TD peers that was not modified by supplementation with probiotics.

[The Therapeutic Potential of Prebiotics and Probiotics in Child and Adolescent Psychiatric Disorders]

The Therapeutic Potential of Prebiotics and Probiotics in Child and Adolescent Psychiatric Disorders Abstract: This short review summarizes the literature available on therapeutic interventions with prebiotics and probiotics and their potential use in psychiatric disorders in childhood, adolescence, and adulthood. Most studies of children and adolescents are done on ADHD and autism spectrum disorders, whereas single reports exist largely on positive effects on cognitive symptoms and quality of life. Initial studies regarding anorexia nervosa point to a potential effect of weight gain and reduction of gastrointestinal symptoms. To date, the effects of prebiotics and probiotics in depression, bipolar disorder, anxiety disorders, and schizophrenia have been mainly investigated in adults. The best reported evidence exists for depression, whereas the effects on depressive symptomatology are small. Positive effects are seen on gastrointestinal symptoms in these disorders. Given these positive effects, the mixed literature reports may result from very heterogeneous study designs. Nevertheless, the high potential of prebiotics and probiotics may be seen for minors with mental health problems. Further studies that include child and adolescent psychiatric populations and reflect the complexity of the gut-brain axis are urgently needed.

Microglial contribution to the pathology of neurodevelopmental disorders in humans

Microglia are the brain's resident macrophages, which guide various developmental processes crucial for brain maturation, activity, and plasticity. Microglial progenitors enter the telencephalic wall by the 4th postconceptional week and colonise the fetal brain in a manner that spatiotemporally tracks key neurodevelopmental processes in humans. However, much of what we know about how microglia shape neurodevelopment comes from rodent studies. Multiple differences exist between human and rodent microglia warranting further focus on the human condition, particularly as microglia are emerging as critically involved in the pathological signature of various cognitive and neurodevelopmental disorders. In this article, we review the evidence supporting microglial involvement in basic neurodevelopmental processes by focusing on the human species. We next concur on the neuropathological evidence demonstrating whether and how microglia contribute to the aetiology of two neurodevelopmental disorders: autism spectrum conditions and schizophrenia. Next, we highlight how recent technologies have revolutionised our understanding of microglial biology with a focus on how these tools can help us elucidate at unprecedented resolution the links between microglia and neurodevelopmental disorders. We conclude by reviewing which current treatment approaches have shown most promise towards targeting microglia in neurodevelopmental disorders and suggest novel avenues for future consideration.

Effects of Walnut and Pumpkin on Selective Neurophenotypes of Autism Spectrum Disorders: A Case Study

Special diets or nutritional supplements are regularly given to treat children with autism spectrum disorder (ASD). The increased consumption of particular foods has been demonstrated in numerous trials to lessen autism-related symptoms and comorbidities. A case study on a boy with moderate autism who significantly improved after three years of following a healthy diet consisting of pumpkin and walnuts was examined in this review in connection to a few different neurophenotypes of ASD. We are able to suggest that a diet high in pumpkin and walnuts was useful in improving the clinical presentation of the ASD case evaluated by reducing oxidative stress, neuroinflammation, glutamate excitotoxicity, mitochondrial dysfunction, and altered gut microbiota, all of which are etiological variables. Using illustrated figures, a full description of the ways by which a diet high in pumpkin and nuts could assist the included case is offered.

Current Knowledge About the Impact of Maternal and Infant Nutrition on the Development of the Microbiota-Gut-Brain Axis

The prenatal and early postnatal periods are stages during which dynamic changes and the development of the brain and gut microbiota occur, and nutrition is one of the most important modifiable factors that influences this process. Given the bidirectional cross talk between the gut microbiota and the brain through the microbiota-gut-brain axis (MGBA), there is growing interest in evaluating the potential effects of nutritional interventions administered during these critical developmental windows on gut microbiota composition and function and their association with neurodevelopmental outcomes. We review recent preclinical and clinical evidence from animal studies and infant/child populations. Although further research is needed, growing evidence suggests that different functional nutrients affect the establishment and development of the microbiota-gut-brain axis and could have preventive and therapeutic use in the treatment of neuropsychiatric disorders. Therefore, more in-depth knowledge regarding the effect of nutrition on the MGBA during critical developmental windows may enable the prevention of later neurocognitive and behavioral disorders and allow the establishment of individualized nutrition-based programs that can be used from the prenatal to the early and middle stages of life.

Dietary pattern in autism increases the need for probiotic supplementation: A comprehensive narrative and systematic review on oxidative stress hypothesis

Autism spectrum disorders (ASDs) are associated with specific dietary habits, including limited food selection and gastrointestinal problems, resulting in an altered gut microbiota. Autistic patients have an elevated abundance of certain gut bacteria associated with increased oxidative stress in the gastrointestinal tract. Probiotic supplementation has been shown to decrease oxidative stress in a simulated gut model, but the antioxidant effects of probiotics on the oxidative stress of the gut in autistic patients have not been directly studied. However, it is speculated that probiotic supplementation may help decrease oxidative stress in the gastrointestinal tract of autistic patients due to their specific dietary habits altering the microbiota. PubMed, Scopus and Web of Science databases and Google Scholar were searched up to May 2023. This systematic-narrative review aims to present the latest evidence regarding the changes in eating habits of autistic children which may further increase the gut microbiota induced oxidative stress. Additionally, this review will assess the available literature on the effects of probiotic supplementation on oxidative stress parameters.

Prevalence of gastrointestinal symptoms in autism spectrum disorder: A meta-analysis

INTRODUCTION

A high prevalence of gastrointestinal (GI) symptoms has been described in children and adolescents with autism spectrum disorder (ASD). In addition, there is evidence that presence of GI symptoms is associated to greater severity of ASD. However, the frequency of GI symptoms in children and adolescents with ASD varies widely across studies, and their true prevalence is unknown. Therefore, the objective of this study was to estimate the prevalence of GI symptoms in children and adolescents with ASD.

MATERIAL AND METHOD

We conducted a meta-analysis following the PRISMA guidelines. We carried out a rapid systematic search for recent clinical and observational studies published from August 2012 in PubMed. The statistical analyses were performed with the software R.

RESULTS

Of 91 potentially eligible articles, only 8 met our inclusion criteria. The prevalence of GI symptoms ranged between 0% and 69%, with an estimated general prevalence of 33% (95% CI, 13%-57%), higher than that reported by a previous meta-analysis for the general paediatric population. This difference is even greater in the specific comparison of studies that applied the paediatric version of the ROME III questionnaire (QPGS-ROME III).

CONCLUSIONS

The results confirmed the hypothesis that there is a higher prevalence of functional GI symptoms in paediatric patients with ASD compared to their neurotypical peers.

Psychobiotics and fecal microbial transplantation for autism and attention-deficit/hyperactivity disorder: microbiome modulation and therapeutic mechanisms

Dysbiosis of the gut microbiome is thought to be the developmental origins of the host's health and disease through the microbiota-gut-brain (MGB) axis: such as immune-mediated, metabolic, neurodegenerative, and neurodevelopmental diseases. Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are common neurodevelopmental disorders, and growing evidence indicates the contribution of the gut microbiome changes and imbalances to these conditions, pointing to the importance of considering the MGB axis in their treatment. This review summarizes the general knowledge of gut microbial colonization and development in early life and its role in the pathogenesis of ASD/ADHD, highlighting a promising therapeutic approach for ASD/ADHD through modulation of the gut microbiome using psychobiotics (probiotics that positively affect neurological function and can be applied for the treatment of psychiatric diseases) and fecal microbial transplantation (FMT).

Topic modeling for multi-omic integration in the human gut microbiome and implications for Autism

While healthy gut microbiomes are critical to human health, pertinent microbial processes remain largely undefined, partially due to differential bias among profiling techniques. By simultaneously integrating multiple profiling methods, multi-omic analysis can define generalizable microbial processes, and is especially useful in understanding complex conditions such as Autism. Challenges with integrating heterogeneous data produced by multiple profiling methods can be overcome using Latent Dirichlet Allocation (LDA), a promising natural language processing technique that identifies topics in heterogeneous documents. In this study, we apply LDA to multi-omic microbial data (16S rRNA amplicon, shotgun metagenomic, shotgun metatranscriptomic, and untargeted metabolomic profiling) from the stool of 81 children with and without Autism. We identify topics, or microbial processes, that summarize complex phenomena occurring within gut microbial communities. We then subset stool samples by topic distribution, and identify metabolites, specifically neurotransmitter precursors and fatty acid derivatives, that differ significantly between children with and without Autism. We identify clusters of topics, deemed "cross-omic topics", which we hypothesize are representative of generalizable microbial processes observable regardless of profiling method. Interpreting topics, we find each represents a particular diet, and we heuristically label each cross-omic topic as: healthy/general function, age-associated function, transcriptional regulation, and opportunistic pathogenesis.

A narrative review on the use of probiotics in several diseases. Evidence and perspectives

Gut microbiota is a complex ecosystem, strictly linked to health and disease, as a balanced composition (referred as eubiosis) is necessary for several physiological functions, while an unbalanced composition (dysbiosis) is often associated to pathological conditions and/or diseases. An altered microbiota could be positively affected and partially restored through probiotic supplementation, among others. This review addresses the effects of probiotics in several conditions, used as case-studies (colorectal cancer, neuro-psychiatric diseases, intestinal diseases, obesity, diabetes, metabolic syndrome, immune system, and musculoskeletal system disorders) by pointing out the clinical outcomes, the mode of action, mainly related to the production of short chain fatty acids (SCFA), the impact of probiotic dose and mode of supplementation, as well as trying to highlight a hit of the most used genera.

Diet in treatment of autism spectrum disorders

Altering the diet to treat disease dates to c. 400 BC when starvation was used to reduce seizures in persons with epilepsy. The current diversity of symptomology and mechanisms underlying autism spectrum disorders (ASDs) and a corresponding lack of disorder-specific effective treatments prompts an evaluation of diet as a therapeutic approach to improve symptoms of ASDs. In this review article, we summarize the main findings of nutritional studies in ASDs, with an emphasis on the most common monogenic cause of autism, Fragile X Syndrome (FXS), and the most studied dietary intervention, the ketogenic diet as well as other dietary interventions. We also discuss the gut microbiota in relation to pre- and probiotic therapies and provide insight into future directions that could aid in understanding the mechanism(s) underlying dietary efficacy.

A review of dietary and nutritional interventions available for management of autism spectrum disorder symptoms in children and adolescents - Kenya

Research on the challenges of raising a child with autism is mostly reported from Europe, North America and Australia. There is limited autism spectrum disorder (ASD) research in Kenya and families lack support as the etiology is linked to witchcraft and sorcery. Research indicates an increase in ASD prevalence globally and in Africa. Malnutrition and neuro-disability are major public health problems in Africa. Approximately one billion people, 15% of the world’s population, have a disability of some kind and 80% live in Low- and Middle-Income countries (LMICs). Of these, 53 million are children aged below 5 years living in sub-Saharan Africa. In Kenya, 2.2% (0.9 million people) live with some form of disability. Children diagnosed with autism spectrum disorder (ASD) suffer from neuro disabilities eliciting: altered sensory processing, restricted interests, and behavioral rigidity. Autism spectrum disorders have no cure, management is by use of interventional targeting autistic symptoms such as linguistic development, non-verbal cognitive development, and motor development. The objectives of this review were: to identify dietary and nutritional interventions available for the management of ASD symptoms in children and adolescents - Kenya, and to analyze the results of existing research in this area in order to understand and describe the characteristics and results of these studies to enable their use in the management of ASD symptoms. Cochrane Library, PubMed, PMC, Google scholar, and Free Full databases were searched to identify studies published between September 2011 and September 2021. Included were studies on nutrition or dietary interventions given to ASD children and adolescents that assessed autistic behavior and/or gastrointestinal symptoms. Excluded were those articles that evaluated surrogate outcomes as the primary outcome such as urinary peptide excretion and other neuro-disabilities other than ASD. Eighteen articles were included: 12 randomized case-control trials, 3 open-label trials, one 2×2 factorial study, and 2 cross-over trials. The following dietary and nutritional interventions were evaluated: gluten and casein-free diet, ketogenic diets; probiotic supplements, specific carbohydrate diets, polyunsaturated fatty acids, vitamin and mineral supplantation (A, B6, B12, D, magnesium, folic acid), and alternative diets. Authors report improvements in the symptoms associated with ASD individuals receiving nutritional interventions such as vitamin and mineral supplementation however, their safety and efficacy needs to be evaluated. The study findings will help policymakers and implementers to understand the consistency and precision and impact of these interventions. These findings will contribute to improving the safety and efficacy of these interventions, positively impacting the health and nutrition outcomes of children and adolescents with ASD. These study findings indicate that more research targeting ASD dietary and Nutritional Interventions for management of ASD symptoms is required in Kenya and other resource constrained settings. Key words: autism spectrum disorder, nutritional intervention, diet therapy, child, adolescent, Kenya

The brain-gut-microbiota axis in the treatment of neurologic and psychiatric disorders

The human gut microbiota is a complex ecosystem made of trillions of microorganisms. The composition can be affected by diet, metabolism, age, geography, stress, seasons, temperature, sleep, and medications. The increasing evidence about the existence of a close and bi-directional correlation between the gut microbiota and the brain indicates that intestinal imbalance may play a vital role in the development, function, and disorders of the central nervous system. The mechanisms of interaction between the gut-microbiota on neuronal activity are widely discussed. Several potential pathways are involved with the brain-gut-microbiota axis, including the vagus nerve, endocrine, immune, and biochemical pathways. Gut dysbiosis has been linked to neurological disorders in different ways that involve activation of the hypothalamic-pituitary-adrenal axis, imbalance in neurotransmitter release, systemic inflammation, and increase in the permeability of the intestinal and the blood-brain barrier. Mental and neurological diseases have become more prevalent during the coronavirus disease 2019pandemic and are an essential issue in public health globally. Understanding the importance of diagnosing, preventing, and treating dysbiosis is critical because gut microbial imbalance is a significant risk factor for these disorders. This review summarizes evidence demonstrating the influence of gut dysbiosis on mental and neurological disorders.

Microbiome-Gut-Mucosal-Immune-Brain Axis and Autism Spectrum Disorder (ASD): A Novel Proposal of the Role of the Gut Microbiome in ASD Aetiology

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterised by deficits in social interaction and communication, as well as restricted and stereotyped interests. Due of the high prevalence of gastrointestinal disorders in individuals with ASD, researchers have investigated the gut microbiota as a potential contributor to its aetiology. The relationship between the microbiome, gut, and brain (microbiome-gut-brain axis) has been acknowledged as a key factor in modulating brain function and social behaviour, but its connection to the aetiology of ASD is not well understood. Recently, there has been increasing attention on the relationship between the immune system, gastrointestinal disorders and neurological issues in ASD, particularly in relation to the loss of specific species or a decrease in microbial diversity. It focuses on how gut microbiota dysbiosis can affect gut permeability, immune function and microbiota metabolites in ASD. However, a very complete study suggests that dysbiosis is a consequence of the disease and that it has practically no effect on autistic manifestations. This is a review of the relationship between the immune system, microbial diversity and the microbiome-gut-brain axis in the development of autistic symptoms severity and a proposal of a novel role of gut microbiome in ASD, where dysbiosis is a consequence of ASD-related behaviour and where dysbiosis in turn accentuates the autistic manifestations of the patients via the microbiome-gut-brain axis in a feedback circuit.

Microbiota and nutrition as risk and resiliency factors following prenatal alcohol exposure

Alcohol exposure in adulthood can result in inflammation, malnutrition, and altered gastroenteric microbiota, which may disrupt efficient nutrient extraction. Clinical and preclinical studies have documented convincingly that prenatal alcohol exposure (PAE) also results in persistent inflammation and nutrition deficiencies, though research on the impact of PAE on the enteric microbiota is in its infancy. Importantly, other neurodevelopmental disorders, including autism spectrum and attention deficit/hyperactivity disorders, have been linked to gut microbiota dysbiosis. The combined evidence from alcohol exposure in adulthood and from other neurodevelopmental disorders supports the hypothesis that gut microbiota dysbiosis is likely an etiological feature that contributes to negative developmental, including neurodevelopmental, consequences of PAE and results in fetal alcohol spectrum disorders. Here, we highlight published data that support a role for gut microbiota in healthy development and explore the implication of these studies for the role of altered microbiota in the lifelong health consequences of PAE.

A Machine Learning Approach to the Diagnosis of Autism Spectrum Disorder and Multi-Systemic Developmental Disorder Based on Retrospective Data and ADOS-2 Score

Early and accurate diagnosis of autism spectrum disorders (ASD) and tailored therapeutic interventions can improve prognosis. ADOS-2 is a standardized test for ASD diagnosis. However, owing to ASD heterogeneity, the presence of false positives remains a challenge for clinicians. In this study, retrospective data from patients with ASD and multi-systemic developmental disorder (MSDD), a term used to describe children under the age of 3 with impaired communication but with strong emotional attachments, were tested by machine learning (ML) models to assess the best predictors of disease development as well as the items that best describe these two autism spectrum disorder presentations. Maternal and infant data as well as ADOS-2 score were included in different ML testing models. Depending on the outcome to be estimated, a best-performing model was selected. RIDGE regression model showed that the best predictors for ADOS social affect score were gut disturbances, EEG retrievals, and sleep problems. Linear Regression Model showed that term pregnancy, psychomotor development status, and gut disturbances were predicting at best for the ADOS Repetitive and Restricted Behavior score. The LASSO regression model showed that EEG retrievals, sleep disturbances, age at diagnosis, term pregnancy, weight at birth, gut disturbances, and neurological findings were the best predictors for the overall ADOS score. The CART classification and regression model showed that age at diagnosis and weight at birth best discriminate between ASD and MSDD.

The importance of comprehensive support based on the three pillars of exercise, nutrition, and sleep for improving core symptoms of autism spectrum disorders

Autism spectrum disorder (ASD) is classified as a neurodevelopmental disorder. The Diagnostic and Statistical Manual of Mental Disorders (DSM)-V, which first described ASD, lists persistent deficits in social communication and interrelationships, as well as limited and recurrent modes of behavior, interests, and activities as diagnostic items. Until recently, understanding the pathophysiology of ASD has been mostly from a neurophysiological perspective, and interventions have been mostly behavioral and psychological. In recent years, however, it has become clear that ASD also affects many bodily systems, including the immune system, the sensorimotor system, and the gut-brain axis, and that these factors simultaneously influence it. In light of this background, a new "connectivome theory" has been proposed as a hypothesis for understanding ASD. "Exercise," "nutrition," and "sleep," which are discussed in this mini-review, have a particularly strong relationship with the immune, musculoskeletal, and gut systems among the pathologies mentioned in the "connectivome theory," furthermore, many reports suggest improvements in stereo-responsive behavior and social and communication skills, which are the core symptoms of ASD. In addition, these interventions are characterized by being less subject to location and cost limitations and excel in the continuity of therapeutic intervention, and the three interventions may have a reciprocal positive impact and may function as three pillars to support ASD.

Impact of Gut Microbiota on Host Aggression: Potential Applications for Therapeutic Interventions Early in Development

Aggression in the animal kingdom is a necessary component of life; however, certain forms of aggression, especially in humans, are pathological behaviors that are detrimental to society. Animal models have been used to study a number of factors, including brain morphology, neuropeptides, alcohol consumption, and early life circumstances, to unravel the mechanisms underlying aggression. These animal models have shown validity as experimental models. Moreover, recent studies using mouse, dog, hamster, and drosophila models have indicated that aggression may be affected by the "microbiota-gut-brain axis." Disturbing the gut microbiota of pregnant animals increases aggression in their offspring. In addition, behavioral analyses using germ-free mice have shown that manipulating the intestinal microbiota during early development suppresses aggression. These studies suggest that treating the host gut microbiota during early development is critical. However, few clinical studies have investigated gut-microbiota-targeted treatments with aggression as a primary endpoint. This review aims to clarify the effects of gut microbiota on aggression and discusses the therapeutic potential of regulating human aggression by intervening in gut microbiota.