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RESEARCH PRODUCT

Depletion of Blautia Species in the Microbiota of Obese Children Relates to Intestinal Inflammation and Metabolic Phenotype Worsening

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Cross-sectional studies conducted with obese and control subjects have suggested associations between gut microbiota alterations and obesity, but the links with specific disease phenotypes and proofs of causality are still scarce. The present study aimed to profile the gut microbiota of lean and obese children with and without insulin resistance to characterize associations with specific obesity-related complications and understand the role played in metabolic inflammation. Through massive sequencing of 16S rRNA gene amplicons and data analysis using a novel permutation approach, we have detected decreased incidence of Blautia species, especially Blautia luti and B. wexlerae, in the gut microbiota of obese children, which was even more pronounced in cases with both obesity and insulin resistance. There was also a parallel increase in proinflammatory cytokines and chemokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], and monocyte chemoattractant protein 1 [MCP-1]) in feces of obese children compared to those of lean ones. B. luti and B. wexlerae were also shown to exert an anti-inflammatory effect in peripheral blood mononuclear cell cultures in vitro, compared to non-obesity-associated species. We suggest that the depletion of B. luti and B. wexlerae species in the gut ecosystem may occur in cases of obesity and contribute to metabolic inflammation leading to insulin resistance.