BMP7 and kidney disorder: In order to understand the putative effect of SSD on peritoneal fibrosis, we aimed to investigate: 1) whether a cross-talk of theTGFβ1/BMP7/Gremlin1 pathways was involved in the progression of peritoneal fibrosis; 2) whether SSD exerted inhibitory effects on peritoneal fibrosis in rat model of kidney disease; 3) whether a potential regulatory effect of SSD on peritoneal fibrosis was dependent on a TGFβ1/BMP7/Gremlin1 pathway cross-talk.