Bifidobacterium adolescentis CCFM1386 relieved prediabetes symptoms by modulating gut microbiota and metabolic profiles in mice

Prediabetes, a hyperglycaemic state preceding pathologic diabetic hyperglycaemia, is a prevalent condition worldwide. In our preliminary population study, we identified Bifidobacterium adolescentis as a key bacterial strain potentially associated with prediabetes alleviation, by analyzing gut microbiota changes in obese subjects with pre- and post-intervention with hypocaloric balanced diet (HBD). To verify its effects, we administered B. adolescentis CCFM1386 via gavage to prediabetic model mice. The strain significantly mitigated weight gain, improved glucose tolerance, especially decreased serum insulin concentrations by 43.8%, and lowered insulin resistance (IR) compared to the model group; and reduced low-density lipoprotein cholesterol (LDL-C) levels in prediabetic mice. Furthermore, it significantly decreased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, demonstrating protective effects on liver and pancreatic tissues as confirmed by histological analysis. To elucidate the underlying mechanisms, we conducted metagenomic sequencing of gut microbiota and non-targeted metabolomics of faecal and serum samples. Our findings revealed that B. adolescentis CCFM1386 helped restore gut microbiota structure, promoted beneficial bacterial growth, and increased the production of beneficial metabolites such as Nicotinate and phenylalanine, thereby influencing multiple metabolic pathways (including protein digestion and absorption, and biosynthesis of amino acids etc.).