SMAD1 and chronic kidney disease: Changes in BMP2/Smads signaling pathway-related proteins as shown in Figure 3, compared with the control group, the expression of BMP-2, p-Smad1, p-Smad5, Osterix, and Runx2 in the CKD-AVF group increased, and the expression of Smad1 and Smad5 was no significant change.