MAS1L and chronic kidney disease: IHC staining showed that the expression of the angiotensin receptors (AT1R, AT2R, MasR, and MrgD) increased significantly in IgAN renal tissues of stage 4 CKD, whether progressive or stable group, compared to those with stage 1 CKD (mild mesangial proliferative glomerulonephritis) at the time of renal biopsy.