GPX4 and congenital secretory chloride diarrhea 1: When staining, 8-OHdG was found mainly throughout the cytoplasm, demonstrating the abundance of oxidative mitochondrial damage in CLD hepatocytes.14 Gene expression for NRF2 and GPX4, which regulate antioxidant response, also tended to be higher in many of the CLD samples, although not significant, further suggesting a reactive response to the mitochondrial injury and oxidative stress in CLD.4,17 These results are consistent with published reports and support the role that oxidative stress has in the pathological mechanism of disease for PBC and PSC.4,17