Title : Gut microbiome and SCFA disturbances in young children from the aral sea region following cardiopulmonary bypass: Clinical and nutritional relevance
Abstract:
Congenital Heart Defects (CHD) remain a leading cause of morbidity and mortality in early childhood and often require surgical correction within the first months of life. Despite advances in pediatric cardiac surgery and intensive care, the early postoperative period continues to be associated with high rates of metabolic, nutritional, and functional complications. Cardiopulmonary Bypass (CPB), while essential for surgical correction, induces systemic inflammatory responses and disrupts microcirculation, making the gastrointestinal tract particularly vulnerable. Alterations in the gut microbiome and its metabolic activity, including Short-Chain Fatty Acid (SCFA) production, may critically influence postoperative nutritional and functional outcomes in young children.
Objective: To evaluate intestinal microbiome composition, SCFA levels, and nutritional status in children aged 0–3 years during the early postoperative period after cardiac surgery with CPB, and to investigate associations between intestinal dysbiosis and impaired physical growth and nutrition.
Methods: A prospective observational study was conducted from August to October 2025 at the Pediatric Intensive Care Unit of the Specialized Scientific and Practical Medical Center of Cardiology and Cardiac Surgery in the Aral Sea region. Twenty children with CHD were included: 12 underwent cardiac surgery with CPB (main group), and 8 were assessed preoperatively (control group). Stool samples were collected before surgery and during the early postoperative period. Microbiome composition was analyzed using quantitative microbiological techniques, and fecal SCFA concentrations (acetate, propionate, butyrate) were measured by gas chromatography. Clinical and nutritional assessments included anthropometry, BMI-for-age z-scores, laboratory markers of protein and micronutrient status, and evaluation of feeding tolerance and functional activity.
Results: Postoperative dysbiosis was observed in children exposed to CPB, characterized by reduced abundance of commensal taxa (Bifidobacterium, Lactobacillus, Bacteroides) and SCFA-producing genera (Rothia, Intestinimonas, Clostridium innocuum), alongside expansion of opportunistic taxa (Enterobacteriaceae, Clostridium spp.). SCFA analysis revealed decreased butyrate and propionate levels with relative acetate predominance. Dysbiosis severity correlated with CPB duration (r=0.42, p<0.05). Reduced SCFA levels were associated with impaired intestinal barrier function (elevated claudin-2, claudin-3, intestinal fatty acid–binding protein, fecal calprotectin) and with postoperative feeding intolerance, insufficient weight gain, and biochemical evidence of protein and micronutrient deficiencies.
Conclusion: Cardiac surgery with CPB in young children from the Aral Sea region induces significant alterations in the gut microbiome and SCFA production, which are closely linked to impaired intestinal barrier integrity, feeding intolerance, and compromised nutritional status. These findings highlight the need for systematic monitoring and targeted modulation of the gut microbiome and nutritional support to improve early postoperative recovery in this vulnerable population.
