HMGB1 and post-traumatic stress disorder: An abnormal gut environment (e.g., gut barrier dysfunction, SCFAs concentrations, and a variety of microbial metabolites) also characterizes the pathology of PTSD (Mellon et al., 2019) Veterans with PTSD have a proinflammatory gut environment that includes higher levels of metabolites of microbial origin, such as acetic, lactic, and succinic acids, and gut barrier dysfunction [lipopolysaccharides (LPS) and lipopolysaccharide-binding proteins,] increased HMGB1, along with an increased number of extracellular vesicles of gut epithelial cell origin (Voigt et al., 2022).