SMAD1 and Peritoneal Fibrosis: Moreover, while previous studies mostly focused on kidney fibrosis, liver and neurological diseases (Chaverneff and Barrett, 2009) (Leeuwis et al., 2011) (L. Wang et al., 2018a) research on a potential role of BMP7, Gremlin, and Smad1/5/8 in peritoneal fibrosis is scarce.