NOS2 and serum lipopolysaccharide activity: Sustained iNOS upregulation, leading to increased NO levels, via peroxynitrite, has been shown to play a major role in the initiation of the intestinal mucosal injury in stressful conditions, such as endotoxemia, hemorrhagic shock, or necrotizing enterocolitis, causing enterocyte apoptosis and disruption of the intestinal barrier and increased bacterial translocation [40].