TGFB1 and Peritoneal Fibrosis: Our previous studies have demonstrated that the aberrant activation of the TGF-β/Smad signaling is associated with the peritoneal dialysis fluid-increased fibrotic peritoneum thickness, α-smooth muscle actin (α-SMA), collagen I, and plasminogen activator inhibitor-1 (PAI-1) expression, leading to the development of peritoneal fibrosis in rats [17], [18].