GDF15 and obesity due to melanocortin 4 receptor deficiency: On the other hand, in chronic inflammatory states, such as atherosclerosis, obesity, steatohepatitis, and liver fibrosis, GDF15 signaling can either aggravate inflammation, e.g., in atherosclerosis (Bonaterra et al. 2012; Preusch et al. 2013), or ameliorate inflammation, such as in obesity, steatohepatitis, and liver fibrosis (Kim et al. 2018; Kim and Lee 2021; Li et al. 2023).