Gut microbiota-driven dysbiosis of the SCFA-immune axis in pediatric allergic rhinitis-constipation comorbidity: mechanisms and synbiotic remodeling.

Children with allergic rhinitis-functional constipation comorbidity exhibited reduced gut microbial alpha-diversity compared to healthy controls.

• Study enrolled 57 AR-FC children aged 0-6 years and 59 age-matched healthy controls (HC)
• Alpha-diversity was significantly reduced in AR-FC subjects (P = 0.003)
• Gut microbiota profiling was performed using 16S rRNA gene sequencing
• Functional pathways were inferred via PICRUSt2

SCFA-producing bacterial taxa were significantly depleted in AR-FC children compared to healthy controls.

• Faecalibacterium prausnitzii was depleted with Log2FC = -2.1 (P = 0.001)
• Bacteroides stercoris was depleted with Log2FC = -1.8 (P = 0.005)
• These depletions suggest disruption of the microbiota-SCFA-immune axis
• The depletions were associated with potential mucosal barrier defects and a bias toward Th2 polarization

Altered functional metabolic pathways were observed in AR-FC children, including upregulated proteasome activity and suppressed LPS biosynthesis.

• Proteasome activity was upregulated (P = 0.01), described as potentially linked to antigen processing
• LPS biosynthesis was suppressed (P = 0.02), described as suggestive of impaired innate immunity
• Functional pathway alterations were inferred using PICRUSt2 analysis

Synbiotic intervention enriched Faecalibacterium abundance and alleviated constipation but reduced Bifidobacterium, reflecting substrate competition.

• A subset of 13 preschoolers aged 3-7 years underwent a 3-month synbiotic intervention (multi-strain probiotics combined with dietary fiber)
• Paired pre- and post-treatment samples were analyzed
• Faecalibacterium abundance increased by +54.8% (P < 0.05)
• Bifidobacterium abundance decreased by -85.2% (P < 0.05)
• The decrease in Bifidobacterium was attributed to substrate competition

Synbiotic intervention induced metabolic remodeling characterized by increased sulfur assimilation and diminished beta-lactam resistance.

• Sulfate reduction increased by +83.2% (P = 0.04)
• Beta-lactam resistance decreased by -35.4% (P = 0.03)
• These changes were observed following the 3-month synbiotic intervention in 13 preschoolers

Gut dysbiosis in AR-FC comorbidity was associated with disruption of the microbiota-SCFA-immune axis, potentially correlating with mucosal barrier defects and Th2 polarization bias.

• Depletion of SCFA-producing taxa (F. prausnitzii and B. stercoris) was linked to immune-metabolic dysregulation
• The authors proposed potential correlation with mucosal barrier defects
• A potential bias toward T helper 2 (Th2) polarization was suggested as a consequence of the dysbiosis
• The authors highlighted the need for strain-specific formulations to achieve comprehensive immune and intestinal restoration