GDF11 and arthritic joint disease: Studies in arthritis and UC in mice demonstrated that GDF11 could inhibit TNF levels in other experimental models, and other studies suggest that upregulation of Tnf is linked to epithelial regeneration and thus could be a mechanism of action of probiotic bacteria in promoting intestinal barrier restoration and immunity (Pagnini et al., 2010; Giorgetti et al., 2015; Wang et al., 2018; Li et al., 2019; Barroso et al., 2022).