Role of gut microbiota in maternal glucose metabolism

Abstract

Gut microbiota plays an important role in daily biological reactions. It is proved that many metabolic diseases are accompanied with pattern change of gut microbiota and pregnancy is also a process with gut microbiota remodeling. Besides, serum IGF-1 level is increased during pregnancy, but the source of increased IGF-1 remains unclear. So far, there is a paper that explored the gut microbiota in pregnant women. However, the diet of pregnant women was not unified in the study, which might have a significant impact on the finding. To exclude the diet effect, pregnant mice with unified diet were used to investigate the association between gut microbiota and maternal glucose metabolism. We found that since the IGF-1 mRNA in liver was declined and fluctuating pattern of IGF-1 mRNA in visceral adipose tissue was similar to that of serum IGF-1, the extra IGF-1 during pregnancy might be derived from visceral adipose tissue instead of liver. In addition, gut microbiota was dramatically remodeling throughout pregnancy with an increase in Proteobacteria and Firmicutes, and a decrease in Bacteroidetes. The pattern change of gut microbiota was closely related to blood glucose level. Moreover, mice exposed to antibiotics before pregnancy showed higher blood glucose level, with which the change of gut microbiota was connected. The diversity of gut microbiota in antibiotic group was obviously decreased, which might eliminate some beneficial bacterial species thereby further worsening the insulin resistance. Therefore, exposure of antibiotics before pregnancy may influence maternal glucose metabolism via altering the composition of gut microbiota during pregnancy. Medical concern should be raised about antibiotics use before planning for pregnancy and relevant precautionary measures should be taken.