Effect of Synbiotic Supplementation on Liver Fibrosis Indices, Inflammatory and Oxidative Stress Biomarkers, Appetite, Metabolic Parameters, and Expression of PPAR-α, UCP1, and UCP2 Genes in Overweight or Obese Adolescents with Metabolic Dysfunction–Associated Steatotic Liver Disease (MASLD): A Randomized Double-Blind Placebo-Controlled Trial

To evaluate the effects of a 16-week synbiotic supplementation on liver, metabolic, inflammatory, oxidative, and gene expression outcomes in adolescents with Metabolic Associated Steatotic Liver Disease.

Randomized, double-blind, placebo-controlled, parallel-group trial (n=126). Randomization (1:1) uses blocks of four.

Multi-center trial conducted at Imam Khomeini and Shahid Motahari hospitals. Participants, parents, investigators, and data analysts are blinded.

Overweight or obese adolescents (13–18 years) with Metabolic Associated Steatotic Liver Disease (CAP ≥ 248 dB/m). Exclusions include chronic heart, kidney, or liver diseases, endocrine disorders, and use of antibiotics, probiotics, or prebiotics within 3 months.

Intervention group receives one daily synbiotic capsule (Familact 2Plus; eight probiotic strains and 38.5 mg FOS). Control group receives identical placebo capsules.

Primary: Change in Controlled Attenuation Parameter. Secondary: Liver stiffness; metabolic, inflammatory, and oxidative indices; appetite; and expression of PPAR-α, UCP1, and UCP2 genes.

This is a single-center, randomized, double-blind, placebo-controlled trial conducted at a clinical center affiliated with Urmia University of Medical Sciences. Eligible participants will be randomly allocated in a 1:1 ratio to either the synbiotic supplementation or placebo group. To ensure a balanced distribution of baseline confounding factors across both arms, stratified block randomization will be performed based on four key variables: sex (female vs. male), age (13–15 vs. 16–18 years), body mass index (<95th percentile vs. ≥95th percentile), and baseline Controlled Attenuation Parameter (CAP score: <260 dB/m vs. ≥260 dB/m), yielding a total of 16 distinct strata. For each stratum, an independent randomization sequence will be generated using STATA software (version 17) with the blockrand package and a fixed block size of 4, applying a predefined random seed to ensure reproducibility. Allocation concealment will be strictly maintained using sequentially numbered, opaque, sealed envelopes (SNOSE) prepared separately for each stratum. The envelopes and uniquely coded, identical-looking supplement/placebo containers will be prepared and managed by an independent researcher/pharmacist who has no involvement in participant recruitment, clinical care, or outcome assessment. Envelopes will only be opened sequentially after formal participant enrollment.

The trial is double-blind. Participants, parents, investigators, clinicians/care providers, study personnel involved in outcome assessment, and data analysts will remain unaware of group assignments. Synbiotic and placebo capsules will be identical in appearance, color, smell, and taste. Capsule containers will be coded according to the allocation list by a pharmacist who will not be involved in data collection or analysis. The randomization code will be broken only after data collection or when potentially required for a serious adverse event. In the event of a serious adverse event, the need for unblinding will be jointly reviewed by the Principal Investigator and the clinical hepatologist.

The participants are adolescents, and the dataset contains sensitive clinical, biochemical, anthropometric, and gene-expression data. The informed consent and the current protocol do not include provisions for sharing individual participant data with external researchers. Therefore, to protect participant confidentiality and minimize the risk of re-identification, deidentified individual participant data will not be shared. Study findings will be disseminated only in aggregate form through scientific publications and presentations.

Study protocol, statistical analysis plan, informed consent form, final study report, deidentified participant data, STATA analysis code, and data dictionary related to this clinical trial.No directly identifying personal information will be shared.

The study documents and deidentified dataset will become available starting 6 months after publication of the main study results or 12 months after completion of the study, whichever occurs first, subject to final approval by the principal investigator and institutional regulations. The materials will remain available for 5 years after the start of data sharing.

The shared materials will be available to qualified researchers, including academic investigators, clinicians, postgraduate students, and other researchers with a methodologically sound research proposal. Requests from non-academic researchers may also be considered, provided that the proposed use is scientifically justified and consistent with ethical and regulatory requirements.

Access will be granted for scientifically and ethically appropriate purposes, such as secondary analyses, validation studies, systematic reviews with individual-level verification if applicable, and educational or methodological research. Applicants must submit a brief proposal stating the research question, analysis plan, requested materials, and intended outputs. Requests will be reviewed by the principal investigator and the research team with attention to scientific merit, participant confidentiality, and consistency with the original informed consent and institutional ethics requirements. Shared data must remain deidentified, must not be used for participant re-identification, and must not be redistributed to third parties without written permission. A data/material transfer agreement may be required before release.

Interested applicants should contact the principal investigator or the designated study contact by email. Requests may also be directed through the affiliated university/research center if applicable.

Applicants should submit an email request including their name, affiliation, CV or brief description of expertise, research question, analysis plan, requested materials, and expected timeline. The request will be reviewed by the principal investigator and study team, and if necessary by the relevant institutional authority. Clarifications may be requested from the applicant. If approved, the applicant may be asked to sign a data/material use agreement before receiving the files. The expected review and response time is approximately 2 to 4 weeks, and the approved materials will be shared electronically in a secure manner.