N.A. SMOLKO^1, 2, R.A. FAIZULLINA¹, YA.O. MUKHAMEDSHINA^1–3, M.I. MARKELOVA², D.R. KHUSNUTDINOVA², G.E. SYNBULATOVA², T.V. GRIGORYEVA², E.A. SADRETDINOVA²

 ¹Kazan State Medical University, Kazan

²Kazan (Volga) Federal University, Kazan

³Academy of Sciences of the Republic of Tatarstan, Kazan

Contact details:

Smolko N.A. — post-graduate student of the Department of Propaedeutics of Children’s Diseases and Faculty Pediatrics; Junior Researcher of Scientific-research laboratory OpenLab «Gene and cellular technologies» of the Institute for Fundamental Medicine and Biology

Address: 49 Butlerov St., 420012 Kazan, Russian Federation, tel.: +7-996-122-50-12, e-mail: sna997@yandex.ru

Autism Spectrum Disorder (ASD) is one of the most prevalent neuropsychiatric conditions in children. The «microbiota–gut–brain» axis plays a crucial role in ASD pathogenesis, whereby dysbiotic changes may be associated with imbalances in this axis, subsequent systemic inflammation, and, consequently, exacerbation of neuropsychiatric symptoms.

The purpose — to optimize approaches for microbiota correction in children with ASD by studying its taxonomic composition and dynamics during probiotic therapy.

Material and methods. The study involved 96 children in the ASD group and 39 children in the control group (aged 3–8 years). The methodology included medical history analysis, physical examination, assessment of neuropsychiatric development, stool analysis using 16S rRNA sequencing, and determination of intestinal permeability markers. Assessments were performed at baseline and, for the ASD group, after 6 months of follow-up; the control group was assessed once.

Results. The study confirmed the presence of characteristic dysbiosis in children with ASD, marked by an increase in opportunistic pathogenic taxa and a deficiency in butyrate-producing bacteria. Probiotic therapy resulted in a partial restoration of intestinal permeability, evidenced by a decrease in zonulin levels (p = 0.018), while the overall structure of dysbiosis persisted, characterized by elevated levels of Prevotella, Sarcina, and Methanobrevibacter and a reduction in short-chain fatty acid-producing bacteria. Dynamic assessment revealed improvements in specific neuropsychiatric development parameters (fine motor skills, aggression, verbal communication). These findings indicate the partial efficacy of probiotics and underscore the need to develop integrated approaches for microbiota correction in ASD.

Conclusions. The study demonstrates the limited effects of probiotics and the persistence of dysbiotic disorders, substantiating the need to develop more effective strategies for microbiota correction. Investigating the microbiota composition and the markers of intestinal permeability when examining children with ASD will allow for the evaluation of therapy effectiveness and the personalization of correction approaches.

Key words: autism spectrum disorder, microbiota, gut, probiotics, children

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