Differences in gut microbiota and its metabolic function among different fasting plasma glucose groups in Mongolian population of China

Background: Many studies reported the association between gut microbiota and type 2 diabetes(T2D)，but it is still unclear which bacterial genus plays a key role and how the metabolic function of gut microbiota changes in the occurrence and development of T2D. Besides, there is insufficient evidence on the association between gut microbiota and T2D in Mongolian population. This study identified the main bacterial genus influencing the occurrence and development of T2D in Mongolian population, and analyzed the changes of metabolic function of gut microbiota. The association between dietary factors and the relative abundance of main bacterial genus or its metabolic function was also studied. Methods: Dietary surveys and gut microbiota analyses were performed on 24 Mongolian volunteers that were divided into T2D (6 cases), PRET2D ( 6 cases) and Control group (12 cases) according to the fasting plasma glucose (FPG) values. The relative abundance and metabolic function of gut microbiota from fecal samples of the volunteers were measured by metagenomic analysis. Correlation analysis was used to evaluate the association between dietary factors, and the relative abundance of the main bacterial genus or its metabolic function. Results: This study found that the relative abundance of gut microbiota and its metabolic function differed significantly across groups, and clostridium genus may be one of the key bacterial genus affecting the occurrence and development of T2D. First, the relative abundance of clostridium genus was significantly different among the three groups. Second, PRET2D or T2D group had a higher relative abundance of metabolic enzymes of most of the gut microbiota than Control group. Third, there was a strong correlation between the relative abundance of clostridium genus and that of many metabolic enzymes, which may be produced by the clostridium genus. Last, carotene intake was negatively correlated with the relative abundance of clostridium genus but positively correlated with tagaturonate reductase of clostridium genus, which catalyzed interconversions of pentose and glucuronate . Conclusions: The clostridium genus of gut microbiota plays an important role in the development of T2D, and it can be a potential biomarker for T2D in Mongolian population. Meanwhile, the metabolic function of gut microbiota has changed during the early stage of T2D, and the changes of the metabolic function of carbohydrate, amino acid, lipid or energy of clostridium genus may play a critical role. In addition, the carotene intake may affect the reproduction and metabolic function of clostridium genus.