Age-related dynamics of gut microbiome alpha diversity in infants and young children with congenital heart defects

Abstract

Introduction. Gut microbiome maturation during the first three years of life is accompanied by increasing taxonomic richness and community evenness. In children with congenital heart defects (CHD), this process may be altered by hypoxia, hemodynamic impairment, feeding factors, medications and hospitalization. Aim. To assess age-related changes in gut microbiome alpha diversity in children from birth to 3 years with CHD compared with healthy peers. Materials and methods . This secondary analysis used data from a prospective observational study conducted at the Khorezm Regional Children’s Multidisciplinary Medical Center in 2023–2026. The analysis included 73 children with CHD and 36 healthy controls divided into three age groups: 0–6 months, 6–12 months, and 1–3 years. Fecal microbiota was assessed by 16S rRNA gene sequencing. Shannon, Simpson, and Pielou indices and the number of bacterial genera were analyzed. Results . All alpha-diversity measures were lower in CHD. At 0–6 months, the Shannon index was 1.49 ± 0.09 versus 2.27 ± 0.24, while the number of genera was 20.5 ± 2.6 versus 40.4 ± 5.9. At 6–12 months, 27.5 ± 1.6 genera were detected in CHD versus55.7 ± 4.0 in controls. At 1–3 years, the Pielou index was 0.513 ± 0.016 versus 0.69 ± 0.03, and the number of genera was 76.1 ± 1.8 versus 120 ± 10. Conclusion . Gut microbiome maturation in CHD is delayed and incomplete. Increasing taxonomic richness is not accompanied by a sustained increase in community evenness.