Perinatal Western-style Diet Exposure associated with Decreased Microglial Counts throughout the Arcuate Nucleus of the Hypothalamus in Japanese Macaques.

Perinatal exposure to a high-fat, high-sugar, Western-style diet (WSD) is associated with altered neural circuitry in the melanocortin system. This association may have an underlying inflammatory component, as consumption of a WSD during pregnancy can lead to an elevated inflammatory environment. Our group previously demonstrated that prenatal WSD exposure was associated with increased markers of inflammation in the placenta and fetal hypothalamus in Japanese macaques. In this follow-up study, we sought to determine whether this heightened inflammatory state persisted into the postnatal period, as prenatal exposure to inflammation has been shown to reprogram offspring immune function, and long-term neuroinflammation would present a potential means for prolonged disruptions to microglia-mediated neuronal circuit formation. Neuroinflammation was approximated in one-year-old offspring by counting resident microglia and peripherally-derived macrophages in the region of the hypothalamus examined in the fetal study, the arcuate nucleus (ARC). Microglia and macrophages were immunofluorescently stained with their shared marker, ionized calcium-binding adaptor protein-1 (Iba1), and quantified in eleven regions along the rostral-caudal axis of the ARC. A mixed effects model revealed main effects of perinatal diet (