Gut microbiota composition and function in pregnancy as determinants of prediabetes at two-year postpartum

AIMS

Deep metagenomics offers an advanced tool for examining the relationship between gut microbiota composition and function and the onset of disease; in this case, does the composition and function of gut microbiota during pregnancy differ in women who develop prediabetes and those who do not at two-year postpartum, and whether the gut microbiota composition associates with glycemic traits.

METHODS

In total, 439 women were recruited in early pregnancy. Gut microbiota was assessed by metagenomics analysis in early (13.9 ± 2.0 gestational weeks) and late pregnancy (35.1 ± 1.0 gestational weeks). Prediabetes was determined using American Diabetes Association criteria as fasting plasma glucose 5.6-6.9 mmol/l analyzed by an enzymatic hexokinase method. Of the women, 39 (22.1%) developed prediabetes by two-year postpartum.

RESULTS

The relative abundances of Escherichia unclassified (FDR < 0.05), Clostridiales bacterium 1_7_ 47FAA (FDR < 0.25) and Parabacteroides (FDR < 0.25) were higher, and those of Ruminococcaceae bacterium D16 (FDR < 0.25), Anaerotruncus unclassified (FDR < 0.25) and Ruminococcaceae noname (FDR < 0.25) were lower in early pregnancy in those women who later developed prediabetes. In late pregnancy, Porphyromonas was higher and Ruminococcus sp 5_1_39BFAA was lower in prediabetes (FDR < 0.25). Furthermore, fasting glucose concentrations associated inversely with Anaerotruncus unclassified in early pregnancy and directly with Ruminococcus sp 5_1_39BFAA in late pregnancy (FDR < 0.25). α-Diversity or β-diversity did not differ significantly between the groups. Predictions of community function during pregnancy were not associated with prediabetes.

CONCLUSIONS

Our study shows that some bacterial species during pregnancy contributed to the onset of prediabetes within two-year postpartum. These were attributable primarily to a lower abundance of short-chain fatty acids-producing bacteria.

Aberrations in the early pregnancy serum metabolic profile in women with prediabetes at two years postpartum

INTRODUCTION

Aberrations in circulating metabolites have been associated with diabetes and cardiovascular risk.

OBJECTIVES

To investigate if early and late pregnancy serum metabolomic profiles differ in women who develop prediabetes by two years postpartum compared to those who remain normoglycemic.

METHODS

An NMR metabolomics platform was used to measure 228 serum metabolite variables from women with pre-pregnancy overweight in early and late pregnancy. Co-abundant groups of metabolites were compared between the women who were (n = 40) or were not (n = 138) prediabetic at two years postpartum. Random Forests classifiers, based on the metabolic profiles, were used to predict the prediabetes status, and correlations of the metabolites to glycemic traits (fasting glucose and insulin, HOMA2-IR and HbA1c) and hsCRP at postpartum were evaluated.

RESULTS

Women with prediabetes had higher concentrations of small HDL particles, total lipids in small HDL, phospholipids in small HDL and free cholesterol in small HDL in early pregnancy (p = 0.029; adj with pre-pregnancy BMI p = 0.094). The small HDL related metabolites also correlated positively with markers of insulin resistance at postpartum. Similar associations were not detected for metabolites in late pregnancy. A Random Forests classifier based on serum metabolites and clinical variables in early pregnancy displayed an acceptable predictive power for the prediabetes status at postpartum (AUROC 0.668).

CONCLUSION

Elevated serum concentrations of small HDL particles in early pregnancy associate with prediabetes and insulin resistance at two years postpartum. The serum metabolic profile during pregnancy might be used to identify women at increased risk for type 2 diabetes.

Global phylogeography of Dengue type 1 and 2 viruses reveals the role of India

Patterns in virus dispersal and epidemiology of viral diseases can be revealed by phylogeographic studies. Currently knowledge about phylogeography of Dengue virus (DENV) Types 1 and 2 is limited. We carried out the phylogeographic analyses for DENV-1 and DENV-2, by the Bayesian Markov Chain Monte Carlo (MCMC) approach, with emphasis on Indian isolates in relation to the global evolutionary dynamics of the viruses. More than 250 E-gene sequences of each virus, available in GenBank, were used for the analyses. The study was focused on understanding the most likely geographical origin for the major genotypes and sub-lineages of DENV-1/DENV-2 and also the possible pathways in the dispersal of the virus. The results showed that for DENV-1, Southeast Asia was the most likely geographical origin and India was determined to be the ancestral location of the Cosmopolitan genotype circulating in India, Sri Lanka, West and East Africa, Caribbean region, East and Southeast Asia. For DENV-2, the ancestral source could not be precisely inferred. Further, in spite of the earliest isolate from Trinidad-1953 of the American genotype, it was depicted that India may have been the probable ancestor of this genotype. India was also determined to be the ancestral location of a subgroup of the Cosmopolitan genotype. It was noted that DENV-1 and DENV-2 were introduced into India during 1940s and 1910s respectively. Subsequently, dispersal of both the viruses between India and different regions including West, East and Central Africa, Southeast and East Asia and Caribbean was inferred. Overall, the current study provides insight into the spatial as well as temporal dynamics of dengue virus serotypes 1 and 2.