PacBio SMRT sequencing of the intestinal flora composition in patients with gestational diabetes mellitus

Abstract:

[Objective] The intestinal flora represents the microbial flora located in the human intestine, and its composition has been related to the occurrence of various diseases in humans. For example, the intestinal flora plays an important role in the pathogenesis of gestational diabetes mellitus (GDM). Therefore, in this study, we evaluated and compared the intestinal flora in pregnant women according to ethnicity (Mongolian or Han) and GDM status using PacBio SMRT sequencing. [Methods] Ninety-seven fecal samples from pregnant women with or without GDM and of Han or Mongolian ethnicity were subjected to full-length 16S rRNA sequencing using the PacBio SMRT system. [Results] Overall, the microbial flora compositions of the pregnant women were similar during the same pregnant stage, and various microbes exhibited different degrees of correlation with core flora levels. We identified 44 species at the species level. The relative abundance of Akkermansia muciniphila was significantly higher in the non-GDM pregnant women than in pregnant women with GDM in the Han population, while no differences were found in the Mongolian women with and without GDM. The relative abundance of Bacteroides uniformis in the intestinal flora of healthy Han pregnant women was significantly higher than that in healthy Mongolian pregnant women, while no differences were found in the GDM groups between ethnicities. Moreover, the functional prediction results showed that the functional composition of the four groups of flora was highly similar, and most of the functional genes were related to energy metabolism. There was no significant difference between the GDM patients and controls in the Han population, but the relative abundance of flora related to inorganic ion transport in Mongolian GDM patients was significantly higher than that of healthy Mongolian pregnant women. [Conclusion] The intestinal flora is generally relatively stable during the same pregnant stage, and ethnic differences do not have a significant impact on the flora during pregnancy. However, changes in some low-abundance organisms such as Akkermansia muciniphila may contribute to alterations in some metabolic activities of the intestinal flora, including those related to intestinal nutrient absorption, which could influence the development of GDM. The results of this study can help elucidate the role of intestinal flora in GDM pathogenesis.