Metformin reduces blood glucose in treatment-naive type 2 diabetes by altering the gut microbiome

Abstract

Abstract Background To investigate the causality between metformin and gut microbiome in the treatment of type 2 diabetes (T2D). Methods This study was conducted on individuals with newly diagnosed and treatment-naive T2D. We used 16s rRNA sequencing to understand the effect of metformin on the composition and diversity of the gut microbiota. We also compared the differences in relative abundances of gut microbiome at the genus level in treatment-naive T2D patients before and after metformin treatment for 2 months and used Spearman rank correlation coefficient analysis of genus abundance in relation to blood glucose and related factors. Results Metformin significantly reduced blood glucose and levels of the related factors in treatment-naive individuals with T2D after 2 months of treatment. 16s rRNA sequencing showed that metformin treatment altered the composition and diversity of the gut microbiome. Differences in relative abundances at the genus level among groups revealed that Megamonas and Klebsiella in T2D groups were significantly higher compared with those in the control group. Treatment with metformin caused a significant reduction in the abundances of Megamonas and Klebsiella. Spearman rank correlation coefficient analysis showed a significant positive correlation between Megamonas and blood glucose, HbA1c, GSP, and ALT. In Klebsiella, a significant positive correlation between HbA1c and ALT was found. Conclusions Metformin reduces blood glucose in T2D by interaction with different gut bacteria, possibly Megamonas and Klebsiella pneumoniae.