GDF15 and Alzheimer disease: In addition, we analyzed the transcript level of the pro-inflammatory cytokine interleukin 6 (IL-6), as AD is characterized by neuroinflammation (Leng and Edison, 2021) and considering that GDF15 acts as an anti-inflammatory molecule (Lambert et al., 2015; Abulizi et al., 2017; Chung et al., 2017; Moon et al., 2020; Conte et al., 2020a).