GDF15 and obesity due to melanocortin 4 receptor deficiency: Taken together, these findings indicate that, in jejunal crypts from patients with obesity, DB altered the expression of immune factors (antimicrobial peptides, mucins, cytokines) and induced a mild stress response that led to the upregulation of mitokine genes that control food intake (GDF15, ADM2) (28, 29) and lipoprotein homeostasis (LDLR).