Using rat models, Sun et al. showed that hippuric acid (HA), a type of protein-bound uremic toxin (PBUT) that accumulates in CKD, disrupted the NRF2-driven antioxidant response, leading to disrupted antioxidant networks and ROS accumulation, resulting in renal fibrosis [66]. This evidence concerns the gene NFE2L2 and renal fibrosis.