Maternal Obesity: Exploring the Interaction Between Gut Microbiota and Immune Responses During Pregnancy in a Mouse Model

This thesis investigates how maternal obesity during pregnancy affects gut microbiota composition (the community of bacteria living in the intestines) and immune responses, and how these changes influence both maternal and fetal health. The research was conducted using a diet-induced obesity mouse model that closely mimics the physiological changes seen in human obesity. Our findings show that maternal obesity disrupts the gut microbiota and alters immune responses during pregnancy compared to lean pregnancies. These changes were characterized by shifts in immune cell populations and immune cell activity, which may contribute to adverse outcomes such as lower fetal weight. Furthermore, we demonstrated a causal role for the gut microbiota in shaping immune responses. By transplanting gut bacteria from obese and lean pregnant mice into germ-free mice (mice that do not carry any bacteria), we showed that obesity-induced microbiota changes directly drive immune alterations. Lastly, we explored whether beneficial bacteria, such as Bifidobacterium, could mitigate obesity-induced immune disturbances. This treatment improved certain maternal and fetal immune parameters and promoted healthier fetal growth. Overall, this research highlights the importance of the gut microbiota and immune regulation during pregnancy, and suggests that targeted interventions, such as probiotics (live beneficial bacteria that support health), may help improve health outcomes for mothers with obesity and their offspring.