Thaw Htet1, Alice Lam2, Iouri Banakh2, Rumes Sriamareswaran1, Samuel Wu1, Jasmina Felsinger1, Katie Mattheisson3, Elisabeth Nye1
Obese pregnant women have a higher risk of developing pregnancy-induced hypertension and preeclampsia. Outside pregnancy, the gut microbiome of obese individuals is different from normal-weight individuals. Low-grade inflammation is a hallmark of obesity. Metabolites excreted by bacteria in the gut microbiome may contribute to hypertension and inflammation. This study aimed to investigate if blood pressure and level of the inflammatory marker PAI-1 are associated with altered gut microbiome composition in overweight and obese women in early pregnancy.
The composition of the gut microbiota was determined in 205 women at 16 weeks gestation from the SPRING study with 16S rRNA sequencing. The expression of butyrate-producing genes in the gut microbiota was assessed by real-time PCR. PAI-1 levels were measured in fasting serum of a subset of 70 women at 16 weeks gestation.
Results: Obese women had significantly higher systolic and diastolic blood pressure than overweight women in early pregnancy. Systolic blood pressure was negatively correlated with abundance of the butyrate-producing genus Odoribacter in the gut microbiome. Butyrate production capacity by the bacteria in the gut microbiome was decreased in women with higher blood pressure. PAI-1 concentrations were increased in obese pregnant women. PAI-1 was inversely correlated with expression of butyrate kinase and abundance of Odoribacter.
The results of this study show that in overweight and obese pregnant women at 16 weeks gestation, the abundance of butyrate producing bacteria and butyrate production in the gut microbiota is significantly negatively associated with blood pressure and with PAI-1. Increasing butyrate-producing capacity may contribute to maintenance of normal blood pressure in overweight and obese pregnant women.