Researchers at Norwich Research Park have found, through a study of mice, the first evidence of how a mother’s gut microbes, the maternal microbiome, can help in the development of the placenta and the healthy growth of the baby.
In collaboration with scientists at the University of East Anglia (UEA) and the University of Cambridge, researchers at the Quadram Institute found that a species of gut bacteria, known to have beneficial effects on the health of both mice and humans, changes the mother’s body during pregnancy. The bacteria affects the structure of the placenta and transport of nutrients that, in turn, impacts on the growing baby.
The gut bacteria, known as Bifidobacterium breve, is widely used as a probiotic, so this study, the first of its kind, could help researchers find ways to combat pregnancy complications, thus ensuring babies have a healthier start to life.
Microbes in our gut, collectively called the gut microbiome, are now known to play a key role in maintaining a person’s health by combating infections and influencing the immune system and metabolism of the body. They achieve these beneficial effects by breaking down food in our diet and releasing active metabolites that influence cells and body processes.
Scientists are starting to better understand the interactions between microbes and the body, facilitated by these metabolites. It’s known that the growing fetus receives nutrients and metabolites from its mother, but to what extent those metabolites are influenced by the maternal microbiome, and how this influences pregnancy and a baby’s health pre-birth, haven’t till now been explored.
Prof Lindsay Hall, who works at the Quadram Institute and the Technical University of Munich, has been studying Bifidobacterium and the microbiome in very early life for many years, previously showing how providing specific probiotics can help premature babies. These bacteria rise in numbers in the microbiome during pregnancy in both humans and mice, and alterations in its levels have been linked to pregnancy complications.
Pregnancy disorders affect around one in 10 pregnant women and any such complications can lead to health problems for the mother and her baby even after pregnancy.
To address this, Prof Hall in collaboration with Dr Amanda Sferruzzi-Perri and Dr Jorge Lopez-Tello from the University of Cambridge, analysed how supplementing pregnant mice with Bifidobacterium affected pregnancy.
Germ-free mice can be bred to be absent of any microbes, allowing comparisons to be made with other mice that have a ‘normal’ microbiome. These comparisons are so valuable for the insights they provide into the role of the microbiome in health because such studies can’t be carried out on humans.
This study identified that the maternal microbiome plays a key role in the communication between mother, placenta and fetus. Finding out how this form of communication works and how to improve it may help many women who develop pregnancy complications, as well as their developing child.
Funded by the Wellcome Trust and the Biotechnology and Biological Sciences Research Council (BBSRC), the study also looked at the effect of feeding germ-free mice the probiotic Bifidobacterium breve.
It found that the maternal gut microbiome, and Bifidobacterium breve specifically, have a role in regulating fetal growth and metabolism.
In the germ-free mice, the fetus did not receive adequate sugar and failed to grow and develop properly. Providing Bifidobacterium breve to germ-free mice improved fetal outcomes by restoring the fetal metabolism, growth and development to the normal levels. The absence of the maternal microbiome also hampered the growth of the placenta in a way that affected fetal growth.
The research team see the placenta as a neglected organ despite its importance for the growth and survival of the fetus, and so are looking to better understand it to help achieve healthier pregnancies for mothers and babies.
Prof Hall said: “Our findings reveal that the maternal microbiome promotes development of the placenta and growth of the fetus. We think this is linked to the altered profile of metabolites and nutrients, which affects nutrient transport from mother to baby across the placenta.
“Excitingly, it appears that adding Bifidobacterium during pregnancy may help to boost how the placenta functions, which has a positive effect on the baby’s growth in utero.”
While these findings show strong indicators of a link between the microbiome of the mother and the development of the baby, further study is required to uncover whether the human maternal microbiome has similar effects to that on mice.
If that proves to be the case, it could provide a relatively simple and low-cost way to help improve pregnancy outcomes with positive benefits for the life-long health of mother and child.
Image: Researchers have been studying how gut bacteria Bifidobacterium boosts the growth of the placenta during pregnancy – Credit: Quadram Institute
