Obesity is a low-grade chronic inflammatory disease.62 HF-induced changes in gut microbiota composition result in an increased proinflammatory state in the organism.63 Microbiota-derived inflammation has been shown to detrimentally alter communication along the gut-brain vagal axis and increased microglia activation in the NTS is one of the hallmark phenotypic observations.12,13,38,40,64,65 HF-HF animals had a significant increase in the number of Iba1+ cells in the NTS as well as overall positive staining compared to LF (LF and LF-LF) (One-way ANOVA, ps < 0.05) (Figure 7). Here, AIF1 is linked to obesity due to melanocortin 4 receptor deficiency.