Placental Insulin-like Growth Factor Signaling and Neurodevelopment: Emerging Evidence from the Placenta–Brain Axis

The field of neuroplacentology is a growing area that focuses on the influence of placental function on brain development. This field has expanded our understanding of the placenta’s crucial role in proper neurodevelopment as well as placental anomalies that increase the risk of adverse neurodevelopmental outcomes. Neuroplacentology studies have revealed distinct roles of placentally provided hormones and nutrients in neurodevelopment whose disruption by perinatal problems, including inflammation, can increase the risk of neurodevelopmental disorders such as autism spectrum disorder and ADHD. Placental insulin-like growth factor signaling significantly influences brain growth in animal model studies and is tightly linked with human neurodevelopmental outcomes. Insulin-like growth factor signaling is well-established as a regulator of placental function and is fundamental in fetal brain cell developmental processes and plays a role in inflammation. Placental insulin-like growth factor signaling underlies the placental production and delivery of hormones and nutrients that are necessary for fetal neural cell proliferation, differentiation, and growth. It is especially important to study this pathway in the placenta due to aberrant insulin-like growth factor signaling found in conditions such as preterm birth, fetal growth restriction, gestational diabetes, and obesity. All these conditions are linked to a greater risk for neurodevelopmental disorders, neuroinflammation, and other anomalies. This research subfield has also revealed sex differences in the insulin-like growth factor signaling pathway that will contribute to understanding the etiologies of these conditions. This area of study has and will continue to identify specific mechanisms, many currently in model systems, which could eventually be leveraged in preventative and interventive care to improve neurodevelopmental outcomes.