Dynamic changes in gut microbiota during pregnancy among Chinese women and influencing factors: A prospective cohort study

Exploring the Association between Anxiety, Depression, and Gut Microbiota during Pregnancy: Findings from a Pregnancy Cohort Study in Shijiazhuang, Hebei Province, China

Negative emotions and gut microbiota during pregnancy both bear significant public health implications. However, the relationship between them has not been fully elucidated. This study, utilizing data from a pregnancy cohort, employed metagenomic sequencing to elucidate the relationship between anxiety, depression, and gut microbiota's diversity, composition, species, and functional pathways. Data from 87 subjects, spanning 225 time points across early, mid, and late pregnancy, were analyzed. The results revealed that anxiety and depression significantly corresponded to lower alpha diversity (including the Shannon entropy and the Simpson index). Anxiety and depression scores, along with categorical distinctions of anxiety/non-anxiety and depression/non-depression, were found to account for 0.723%, 0.731%, 0.651%, and 0.810% of the variance in gut-microbiota composition (p = 0.001), respectively. Increased anxiety was significantly positively associated with the abundance of Oscillibacter sp. KLE 1745, Oscillibacter sp. PEA192, Oscillibacter sp. KLE 1728, Oscillospiraceae bacterium VE202 24, and Treponema socranskii. A similar association was significantly noted for Oscillibacter sp. KLE 1745 with elevated depression scores. While EC.3.5.3.1: arginase appeared to be higher in the anxious group than in the non-anxious group, vitamin B12-related enzymes appeared to be lower in the depression group than in the non-depression group. The changes were found to be not statistically significant after post-multiple comparison adjustment.

Interactions between host and gut microbiota in gestational diabetes mellitus and their impacts on offspring

Gestational diabetes mellitus (GDM) is characterized by insulin resistance and low-grade inflammation, and most studies have demonstrated gut dysbiosis in GDM pregnancies. Overall, they were manifested as a reduction in microbiome diversity and richness, depleted short chain fatty acid (SCFA)-producing genera and a dominant of Gram-negative pathogens releasing lipopolysaccharide (LPS). The SCFAs functioned as energy substance or signaling molecules to interact with host locally and beyond the gut. LPS contributed to pathophysiology of diseases through activating Toll-like receptor 4 (TLR4) and involved in inflammatory responses. The gut microbiome dysbiosis was not only closely related with GDM, it was also vital to fetal health through vertical transmission. In this review, we summarized gut microbiota signature in GDM pregnancies of each trimester, and presented a brief introduction of microbiome derived SCFAs. We then discussed mechanisms of microbiome-host interactions in the physiopathology of GDM and associated metabolic disorders. Finally, we compared offspring microbiota composition from GDM with that from normal pregnancies, and described the possible mechanism.

Imbalance of gut microbiota in gestational diabetes

AIM

To investigate the differences in gut microbiota composition among nonpregnant women of reproductive age, healthy pregnant women, and gestational diabetes (GD) patients.

METHODS

A total of 45 outpatients were enrolled and divided into three groups: nonpregnant women of reproductive age (control group, n = 23), healthy pregnant women (normal group, n = 10), and GD patients (GD group, n = 12). Faecal samples were collected and sequenced using 16S rRNA gene sequencing to analyse the microbial composition.

RESULTS

(1) Pregnant patients exhibited an increase in the abundance of Streptococcus (Pnormal = 0.01286, PGD = 0.002965) and Blautia (Pnormal = 0.0003924, PGD = 0.000246) but a decrease in the abundance of Roseburia (Pnormal = 0.0361, PGD = 0.007075), Phascolarctobacterium (Pnormal = 0.0003906, PGD = 0.02499) and Lachnoclostridium (Pnormal = 0.0003906, PGD = 0.03866). (2) Compared with healthy pregnant women, GD patients had an excessive increase in Streptococcus abundance and decrease in Roseburia abundance. The increase in Blautia abundance and the decrease in Phascolarctobacterium and Lachnoclostridium abundance in GD patients were less than those in healthy pregnant women. (3) The abundance of Faecalibacterium prausnitzii decreased significantly in GD patients (PGD = 0.02985) but not in healthy pregnant patients (Pnormal = 0.1643).

CONCLUSIONS

Abnormal increases and decreases in the abundances of gut microbiota components, especially Faecalibacterium prausnitzii, were observed in GD patients.

TRIAL REGISTRATION

The cross-sectional research was conducted in accordance with the Declaration of Helsinki, and approved by Sir Run Run Shaw Hospital Clinical Trials and Biomedical Ethics Committee. The study has been registered in the Chinese Clinical Trial Registry (ChiCTR1900026164, 24/09/2019, http://www.chictr.org.cn/showproj.aspx?proj=43,455 ).

Association between gut microbiota, microbial network, and immunity in pregnancy with a focus on specific bacterial clusters

Background

The community characteristics of the gut microbiota are not well defined and are not as widely studied as the functions of individual bacteria. This study aims to investigate the community composition of intestinal flora in women of childbearing age by conducting cluster analysis of gut microbiota and analyzing the relationship between different clusters and immune status.

Methods

A total of 45 women of childbearing age were recruited in the study, including 15 non-pregnant women and 30 women in late pregnancy, and stool samples were collected twice during the third trimester, specifically at 32 weeks and at full term. The gut microbiota data was analyzed using 16S rRNA amplicon sequencing. Partitioning Around Medoids algorithm was employed to assess microbial clustering patterns. Microbial network for each cluster was performed and plasm cytokines were measured to analyze the relationship between specific genera and immune state in clusters.

Results

There were three distinct clusters of intestinal community composition in women of childbearing age. Cluster 1 (PAM_1) was characterized by a high abundance of Bacteroides, while cluster 2 (PAM_2) showed higher levels of Bifidobacterium and Blautia, along with a significantly increased Firmicutes to Bacteroidota ratio. Cluster 3 (PAM_3) displayed a high abundance of Escherichia-shigella. PAM_1 was the most dominant cluster in non-pregnant women, and this dominant cluster was also one of the main in late pregnancy. At full term, the majority of subjects retained the same cluster as at 32 weeks, while a few experienced a shift. The microbial correlation networks differed across the three clusters, with PAM_1 exhibiting higher modularity and fewer connections. Analysis of the correlation between genera and plasma cytokines showed significant differences in their associations with cytokines between pregnancy and nonpregnancy within the same cluster, and the same genera had different effects in different clusters.

Conclusion

Women of childbearing age exhibit three distribution patterns of gut microbiota, and the intestinal clusters reshaped during late pregnancy in a small population. Different clusters may have diverse immunomodulatory effects in different physiological states. When studying the gut microbiome during pregnancy, it is crucial to consider the cluster differences within healthy women.

Analysis of Gut Characteristics and Microbiota Changes with Maternal Supplementation in a Neural Tube Defect Mouse Model

Adequate nutrient supply is crucial for the proper development of the embryo. Although nutrient supply is determined by maternal diet, the gut microbiota also influences nutrient availability. While currently there is no cure for neural tube defects (NTDs), their prevention is largely amenable to maternal folic acid and inositol supplementation. The gut microbiota also contributes to the production of these nutrients, which are absorbed by the host, but its role in this context remains largely unexplored. In this study, we performed a functional and morphological analysis of the intestinal tract of loop-tail mice (Vangl2 mutants), a mouse model of folate/inositol-resistant NTDs. In addition, we investigated the changes in gut microbiota using 16S rRNA gene sequencing regarding (1) the host genotype; (2) the sample source for metagenomics analysis; (3) the pregnancy status in the gestational window of neural tube closure; (4) folic acid and (5) D-chiro-inositol supplementation. We observed that Vangl2+/Lp mice showed no apparent changes in gastrointestinal transit time or fecal output, yet exhibited increased intestinal length and cecal weight and gut dysbiosis. Moreover, our results showed that the mice supplemented with folic acid and D-chiro-inositol had significant changes in their microbiota composition, which are changes that could have implications for nutrient absorption.