Role of the Gut Vascular Barrier and Microbiota in Autism Spectrum Disorders (DSA/GVB)

February 27, 2026 updated by: Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta

Role of the Gut Vascular Barrier and Microbiota in Autism Spectrum Disorders: Evaluation of Efficacy of Postbiotic-based Nutraceutical Treatment

Recent research links gut microbiota alterations to Autism Spectrum Disorders (ASD), a neurobiological condition with multifactorial bases. In some ASD patients, altered gut flora and increased intestinal permeability are observed, influencing the central nervous system's development and function. Chronic gastrointestinal (GI) symptoms are commonly associated with ASD and correlate with its severity. This non-pharmacological interventional clinical study aims to investigate the role of gut microbiota on ASD and the effectiveness of postbiotic-based dietary supplements in children aged 3-8 years old. Gastrointestinal symptoms, behavioral profile and analysis of intestinal metagenomic and metabolomic profiles will be assessed before and after one-month treatment. The results of the study could enhance understanding of non-pharmacological therapeutic approaches in ASD and improve clinical management strategies and the behavioural functioning for children with ASD.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Modulating the microbiota could be an effective way to improve gastrointestinal issues and related behavioral symptoms in children with ASD, offering new treatment avenues. There is particular interest in alternatives to fecal microbiota transplantation, such as postbiotic supplements, which contain molecules naturally released during microbiota metabolism.

These molecules can regulate intestinal homeostasis and microbe-host interactions generating health benefits, possess anti-inflammatory and immunomodulatory activities, and contribute to the barrier activity of the intestinal epithelium. In line with findings for other nutraceutical therapies, dietary supplementation with postbiotics could resolve bowel problems in children with ASD and have positive consequences on behavioral regulation; however, the data collected in the literature is still scarce and limited to studies on mouse models of ASD.

This non-pharmacological clinical study, part of a collaboration between Fondazione IRCCS Istituto Neurologico Carlo Besta (FINCB) and Istituto Clinico Humanitas (ICH), evaluates postbiotic-based supplements' impact on gut microbiota's role in ASD.

Stool samples will be collected from patients at FINCB and FDG, and transported to ICH for analysis of the intestinal bacterial community and intestinal permeability. Participants will then receive a postbiotic-based dietary supplement. After treatment, changes in bowel habits, intestinal bacteria characteristics, intestinal permeability, and any behavioral changes will be evaluated.

Existing literature highlights the protective effects of postbiotics derived from Lactobacillus paracasei CNCM I-5220 on the intestine, specifically contributing to the maintenance of intestinal barrier integrity and protection against leaky gut syndrome.

Unlike probiotics, it provides immediate benefits without live bacteria risks, offering a safe alternative for fragile populations. PostbiotiX Comfort®, which includes the same fermented FOS by L. paracasei found in various infant food supplements (such as Smart D3 Matrix, Polivit Immuno Matrix, and Idra Matrix), will be utilized in this study. These products have been safely used in other formulations without any recorded safety concerns and have demonstrated an excellent toxicological profile.

Study Type

Interventional

Enrollment (Estimated)

90

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Italy
      • Milan, Italy
        • Recruiting
        • IRCCS Humanitas Reasearch Hospital (ICH) Laboratory of Microbiota and Mucosal Immunology
        • Contact:
    • MI
      • Milan, MI, Italy, 20133

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Group 1 and 2:

Inclusion criteria

  • Diagnosis of ASD according to DSM-5 diagnostic criteria;
  • Clinical neurological evaluation by child neurologist and neuropsychologist with administration of standardized instruments such as Autism Diagnostic Observation Schedule-2 (ADOS-2) and/or Autism Diagnostic Interview-Revised (ADI-R) to support diagnosis;
  • Assessment of psychomotor or intellectual development (Griffiths Scales, Wechsler Scales, Leiter Scale)
  • Assessment of the following symptoms in the past three months: constipation, diarrhea, abnormal stool consistency, abnormal stool smell, flatulence, abdominal pain, unexplained daytime irritability, and nighttime awakening, and abdominal tenderness. The degree of gastrointestinal disturbances will be quantified before recruitment using an Italian version of the GI Severity Index. A score of at least 2 in a single item of gastrointestinal symptoms (item 1-6) was required for entry into the symptomatic group.
  • Signed informed consent for analysis of intestinal microbiota and metabolome and administration of nutraceutical therapy with PostbiotiX Comfort ®.

Group 3 Inclusion criteria

  • Males or females aged between 3 and 8 years whit typical development and absence of gastrointestinal symtomps
  • Signed informed consent for analysis of intestinal microbiota and metabolome

Exclusion Criteria:

Group 1 and 2

  • Exclusion Criteria
  • Children with syndromic ASD or defined genetic diseases;
  • Subjects with significant health problems requiring surgical treatment or continuous medical; treatment;
  • Severe gastrointestinal problems requiring immediate (life-threatening) treatment;
  • Severely underweight/malnourished children;
  • Use of medications that may affect biomarkers assessed, for example: antibiotics and/or pre-, probiotics within 1 month prior to enrollment.

Group 3 exclusion criteria

- Participants with gastrointestinal problems requiring immediate (life-threatening) treatment, or with gastrointestinal symptoms such as chronic irregular bowel movements (constipation, diarrhea), encopresis, recurrent abdominal bloating and pain, gastroesophageal reflux and vomiting, or food aversion.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Group 1 (ASD with gastrointestinal symptoms):
30 patients with Autism Spectrum Disorder and coexisting gastrointestinal disorders, aged 3 to 8 years (male or female)
Dietary supplement: PostbiotiX Comfort®
Treatment with a postbiotic dietary supplement, PostbiotiX Comfort®, administered for 1 month in participants from Group 1 and Group 2.
Other: Group 2 (ASD without gastrointestinal symptoms)
30 participants with Autism Spectrum Disorder without gastrointestinal disorders, aged 3 to 8 years (male or female)
Dietary supplement: PostbiotiX Comfort®
Treatment with a postbiotic dietary supplement, PostbiotiX Comfort®, administered for 1 month in participants from Group 1 and Group 2.
Other: Group 3 (Typically developing)
30 participants with typical neurodevelopment and no gastrointestinal symptoms, aged 3 to 8 years (male or female)
Other: Control
Participants in Group 3 do not receive any treatment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Modulation of Gastrointestinal Symptoms in ASD with Postbiotic Supplement
Time Frame: 24 months

The presence of gastrointestinal symptoms will be assessed at recruitment (T0) using the GI Severity Index.

Subjects recruited will be treated with the postbiotic-based dietary supplement, PostbiotiX Comfort®, once daily for 1 month.

The GI Severity Index will be repeated within one week after the end of the treatment (T1) to quantify changes in bowel regulation and one month after the end of the treatment (T2) to assess the stability of the observed changes.
24 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Effects of postbiotics on sleep regulation
Time Frame: 24 months

Standardized behavioral assessments will be conducted through parents/caregivers reported questionnaires to evaluate the effects of postbiotic supplementation on sleep regulation. Sleep disturbances will be assessed through validated instruments designed to investigate difficulties related to sleep onset and maintenance, respiratory sleep disturbances, disorder of arousal, wake-sleep transition, excessive daytime sleepiness, and nocturnal hyperhidrosis.

Sleep regulation will be assessed using the italian version of the Sleep Disturbance Scale for Children. The scale consists of 26 items rated on a 5-point Likert scale (1 = never; 2 = occasionally; 3 = sometimes; 4 = often; 5 = always). The total raw score ranges from 26 to 130, with higher scores indicating greater severity of sleep disturbances.

Assessments will be conducted at three time points: baseline (T0), at enrollment in the interventional study; post-treatment (T1), within one week after the end of treatment; and follow-up (T
24 months
Effects of postbiotics on behavioral regulation
Time Frame: 24 months

Standardized behavioral assessments will be conducted through parents/caregivers reported questionnaires to evaluate the effects of postbiotic supplementation on behavioral regulation. Emotional and behavioral regulation will be assessed through validated instruments designed to investigate the presence and severity of emotional and behavioral problems, including internalizing and externalizing symptoms.

Behavioral and emotional problems will be assessed using the Italian versions of the Child Behavior Checklist (CBCL) according to age. The instrument consists of items rated on a 3-point Likert scale (0 = not true; 1 = somewhat or sometimes true; 2 = very true or often true). Higher scores indicate greater severity of emotional and behavioral problems. Raw scores will be converted into standardized T-scores (mean = 50, standard deviation = 10).

Assessments will be performed at three time points: baseline (T0), at enrollment in the interventional study; post-treatment (T1)
24 months
Effects of postbiotics on sensory profile
Time Frame: 24 months

Standardized behavioral assessments will be conducted through parents/caregivers reported questionnaires to evaluate the effects of postbiotic supplementation on sensory profile.

The sensory profile will be assessed using the Sensory Profile-2 (Italian version), completed by parents/caregivers for children aged 3-8 years. The questionnaire evaluates sensory functioning, self-regulation behavioral responses and the frequency of behavioral responses to environmental sensory stimuli. Raw scores are calculated for each sensory domain; higher scores indicate greater deviation from typical sensory processing patterns.

Assessments will be performed at three time points: baseline (T0), at enrollment in the interventional study; post-treatment (T1), within one week after the end of treatment; and follow-up (T2), within one month after the end of treatment to assess the stability of the observed changes. All questionnaires completed by the parents/caregivers will subsequently be discussed with
24 months
Metagenomic analyses in typically developing children and in ASD before and after postbiotic treatment
Time Frame: 24 months

Fecal samples obtained from control subjects and children with ASD with and without gastrointestinal symptoms. For the latter group, samples will be collected both prior to the initiation of supplement therapy (T0) and after treatment (T1).

Taxonomic and functional profiling of the fecal microbiota will be performed using shallow shotgun metagenomic sequencing. Total bacterial DNA will be extracted from fecal samples and sequenced using Illumina platforms. Taxonomic analyses will be performed at Species-level Genome Bin (SGB) resolution (8th taxonomic rank). Functional analyses will be based on destratified gene family and metabolic pathway abundances, with pathway annotation performed against the MetaCyc database. Differential abundance analyses (DAAs) will be performed on taxonomic profiles expressed as relative abundances and on gene family and pathway profiles normalized to copies per million (CPM) Unit of measure: Relative abundance of bacterial taxa (%)
24 months
Metabolomic analyses in typically developing children and in ASD before and after postbiotic treatment
Time Frame: 24 months

The following laboratory tests will be performed on fecal samples obtained from control subjects and children with ASD with and without gastrointestinal symptoms. For the latter group, samples will be collected both prior to the initiation of supplement therapy (T0) and after treatment (T1). Untargeted metabolomic analysis will be performed on fecal samples to identify metabolites of bacterial origin. Metabolites will be detected and quantified using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS), followed by bioinformatic analysis.

Unit of measure:

• Relative or absolute metabolite abundance (normalized peak intensity/concentration)
24 months
Intestinal permeability analyses in typically developing children and in ASD before and after postbiotic treatment
Time Frame: 24 months

The following laboratory tests will be performed on fecal samples obtained from control subjects and children with ASD with and without gastrointestinal symptoms. For the latter group, samples will be collected both prior to the initiation of supplement therapy (T0) and after treatment (T1). Intestinal permeability will be assessed by quantifying fecal levels of zonulin and albumin using commercially available enzyme-linked immunosorbent assays (ELISA). Increased fecal zonulin levels will be interpreted as indicative of tight junction disassembly and increased epithelial permeability. Elevated fecal albumin concentrations will be interpreted as a marker of intestinal barrier dysfunction associated with inflammatory leakage across the intestinal mucosa . Both biomarkers will be analyzed as indicators of altered intestinal permeability and gut barrier integrity.

Unit of measure:

  • Zonulin family peptides: concentration (e.g., ng/mL or ng/g of feces)
  • Albumin: concentration (e.g., ng/mL
24 months
Investigation of the relationships between metagenomic/metabolomic profiles and behavioral/GI outcomes in children with ASD
Time Frame: 24 months

Correlation analyses will be performed to investigate the relationships between metagenomic and metabolomic profiles and behavioral and gastrointestinal outcomes in children with ASD. This initial analysis will enable the identification of significant associations between microbial diversity, metabolite abundance, and clinical measures potentially modulated by postbiotic treatment.

Metagenomic, metabolomic, and intestinal permeability data will then be integrated with behavioral outcomes using advanced computational multi-omics approaches. Following data normalization and harmonization through standardized pipelines, metagenomic and metabolomic datasets will be combined using network-based integration strategies and multivariate methods, including Canonical Correlation Analysis (CCA), sparse Partial Least Squares (sPLS), and Multi-Omics Factor Analysis (MOFA), to identify shared functional signatures, key microbial-metabolic interactions, and convergent pathways across datasets.

Cross
24 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta

Collaborators

Istituto Clinico Humanitas

Investigators

  • Principal Investigator: Stefano D'Arrigo, MD, Fondazione IRCCS Istituto Neurologico Carlo Besta

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 21, 2023

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

January 19, 2026

First Submitted That Met QC Criteria

February 27, 2026

First Posted (Actual)

March 4, 2026

Study Record Updates

Last Update Posted (Actual)

March 4, 2026

Last Update Submitted That Met QC Criteria

February 27, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DSA/GVB

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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