Poster Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2015

Decreased intestinal butyrate-producing capacity at 16 weeks gestation is associated with increased maternal BMI and future GDM status. (#116)

Luisa F Gomez-Arango 1 2 , Mark Morrison 3 , Alicia Kang 3 , Helen L Barrett 1 2 4 , H David McIntyre 2 5 , Leonie K Callaway 1 2 4 , Marloes Dekker Nitert 1 2
  1. UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
  2. School of Medicine, The University of Queensland, Herston, QLD, Australia
  3. Diamantina Institute, The University of Queensland, Woolongabba, QLD, Australia
  4. Obstetric Medicine, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
  5. Obstetric Medicine, Mater Health Services, South Brisbane, QLD, Australia

Background: Overweight or obese pregnant women have increased risk of adverse outcomes, some of which have been linked to alterations in the gut microbiome and dysbiosis. The short-chain fatty acid butyrate is produced by the gut microbiota and widely viewed as a biomarker of healthy gut function because of its effects on gut homeostasis, inflammation, epigenetic regulation and pancreatic beta cell function.

Aim: This study compares the butyrate-producing capacity of intestinal bacteria and gut microbial profiles between 88 overweight (BMI 25-29.9 kg/m2), 97 obese (BMI 30-39.9 kg/m2) and 30 morbidly obese (>40 kg/m2) women at 16 weeks gestation from the SPRING cohort1.

Methods: Quantification of the main bacterial butyrate-synthesis genes, butyryl-CoA:acetate CoA-transferase (BCoATscr aka BUT) and butyrate-kinase (BUK) were assessed by quantitative PCR.Fecal microbiota profiles (n=108) were assessed by 16S rRNA sequencing and the relative abundances of butyrate producers from Clostridium clusters IV and XIVa were compared.

Results: BUT and BUK copy numbers were variable among women (BUT range 1.4 x 105 - 2.3 x 108 copies/15 ng DNA, BUKrange 0 - 7.8 x 106 copies/15 ng DNA). Copy numbers of both BUT and BUK were negatively correlated with maternal BMI (BUT: Spearman’s rho -0.139, p=0.04, BUK: Spearman’s rho -0.141, p=0.03). 31 women who developed gestational diabetes mellitus (GDM) at 28 weeks gestation displayed lower BUTcopy numbers compared to non-GDM (p=0.012) but no difference in BUK copy numbers (p=0.156) at 16 weeks gestation. Relative abundances of the known butyrate producers from Clostridium clusters IV and XIVa were positively associated with BUT copy numbers (Spearman’s rho 0.221, p=0.022).

Conclusion: Pregnant women with a higher BMI have lower butyrate-producing capacity in their gut microbiome, which may influence their inflammatory and metabolic health: women who later developed GDM had lower copy numbers of the main butyrate producing gene BUT.

  1. Nitert MD, Barrett HL, Foxcroft K, Tremellen A, Wilkinson S, Lingwood B, Tobin JM, McSweeney C, O'Rourke P, McIntyre HD, Callaway LK 2013 SPRING: an RCT study of probiotics in the prevention of gestational diabetes mellitus in overweight and obese women. BMC pregnancy and childbirth 13:50.