FMO5 and chronic kidney disease: In early stages of CKD, continuous low and chronic inflammation in CKD patients might trigger the generation of NADPH oxidase and MPO by polymorphonuclear neutrophils and monocyte-macrophages, which promoted formation of reactive oxygen species (ROS) and synergistically participated in the oxidative stress process (Locatelli et al., 2003; Putri and Thaha, 2014).