Maternal Interleukin-6 Is Associated With Macaque Offspring Amygdala Development and Behavior

Area of Science:

• Neuroscience
• Developmental Biology
• Immunology

Background:

• Maternal inflammatory cytokines, such as interleukin-6 (IL-6), are implicated in neurodevelopmental outcomes.
• Previous studies show associations between maternal IL-6 and brain phenotypes at single time points.
• The longitudinal impact of maternal IL-6 on offspring brain development trajectory is not well understood.

Purpose of the Study:

• To investigate the relationship between maternal IL-6 levels during pregnancy and offspring amygdala volume development.
• To examine the association between maternal IL-6 and anxiety-like behavior in offspring.
• To explore the mediating role of amygdala volume in the link between maternal IL-6 and behavior.

Main Methods:

• Longitudinal study of 39 Japanese macaque offspring (18 female) with MRI scans at 4, 11, 21, and 36 months.
• Maternal plasma IL-6 levels were measured in the third trimester of pregnancy.
• Offspring anxiety-like behavior was assessed at 11 months of age.

Main Results:

• Increased maternal IL-6 was associated with smaller left amygdala volume at 4 months postpartum.
• Higher maternal IL-6 predicted more rapid amygdala growth from 4 to 36 months.
• Maternal IL-6 levels predicted offspring anxiety-like behavior at 11 months, mediated by early amygdala volume.

Conclusions:

• Maternal IL-6 influences the trajectory of amygdala development in offspring.
• Maternal inflammation may contribute to the development of anxiety-like behaviors through its effects on early brain development.
• These findings highlight the critical role of the prenatal inflammatory environment in shaping neurodevelopmental trajectories.