GSTM1 and acute kidney injury: The role of Hb in the induction of AKI is similar to that of Mb, with tubular cell iron overload being the main cause of eventual acute renal failure or tubular necrosis (Tang et al., 2021); studies have shown that free Hb levels are a significant independent risk factor for renal impairment after cardiac surgery (Leaf et al., 2019).