SMAD3 and acute kidney injury: Compared with the patients in the non-AKI group by ELISA detection, the levels of TGF-β1 and Smad3 in serum of patients in the AKI group were significantly higher (non-AKI vs. AKI group: TGF-β1: 154.7 ± 33.6 vs 412.6 ± 62.8 ng/L, t = 18.10, P < 0.001; Smad3: 9.1 ± 3.8 vs 27.1 ± 5.2 ng/L, t = 13.97, P < 0.001), as shown in Figure 5.