Maternal obesity alters myeloid immune function in the offspring

Maternal obesity is a significant public health issue with short- and long-term consequences for the mother's and the offspring's health. In this context, the neonatal immune system in the children of women with pregestational obesity is characterised by an altered inflammatory profile. The mechanisms that potentially affect the development and function of immune cells during fetal development, at birth and during the postnatal life in the children of women with obesity are unknown. Some insights into these mechanisms have been studied in animal models of maternal obesity; however, human studies are limited and are greatly required. This review aims to examine the impact of maternal obesity on fetal myeloid immune cells and explores potential mechanisms that underlie early-life immune programming. Specifically, we include a summary of human and animal studies on the placenta and umbilical cord blood in the context of the inflammatory milieu of maternal obesity, with special emphasis on the phenotypes, functions and epigenetic changes in fetal myeloid cells and their haematopoietic progenitors. Key findings suggest that maternal obesity may induce fetal programming of immune-training-like effects in myeloid cells from early stages of fetal life, resulting in a blunted postnatal immune response. This novel perspective highlights the potential short- and long-term immunological consequences of maternal obesity on offspring, underscoring the critical need for interventions targeting the health of women of childbearing age to prevent acute and chronic immune-related conditions in future generations.