Clinical and Translational Considerations for Understanding Depression and Anxiety in Patients with Inflammatory Bowel Disease

Figure 1

Anxiety and depression SPF and GF mouse models. (a) Specific pathogen free (SPF) mice are exposed to microbes and develop mature populations containing trillions of microbes throughout their body (e.g., skin, genital, and intestinal tract). SPF colonized mice have mature immune systems and are often used as the wild-type microbial community background in murine studies. (b) Germ free (GF) mice are bred without exposure to any microbes and are often used to study microbial community or specific population member (monocolonization) impact on host health. SPF and GF mice can be studied on varied genetic backgrounds (e.g., BALB/c and NMRI). (c, d) When exposed to stress (+Stress), SPF mice develop anxiety and depression behaviors while GF mice do not display these behaviors under stress or in the presence of a healthy community (+Healthy Community). GF mice do display anxiety and depression when colonized with a human microbial community from patients with major depressive disorder (+MDD Community) (figure created with http://BioRender.com).