Redox Chemistry: Implications for Necrotizing Enterocolitis

Abstract

Reduction-oxidation (redox) chemistry plays a vital role in human homeostasis. These reactions play critical roles in energy generation, as part of innate immunity, and in the generation of secondary messengers with various functions such as cell cycle progression or the release of neurotransmitters. Despite this cornerstone role, if left unchecked, the body can overproduce reactive oxygen species (ROS) or reactive nitrogen species (RNS). When these overwhelm endogenous antioxidant systems, oxidative stress (OS) occurs. In neonates, OS has been associated with retinopathy of prematurity (ROP), leukomalacia, and bronchopulmonary dysplasia (BPD). Given its broad spectrum of effects, research has started to examine whether OS plays a role in necrotizing enterocolitis (NEC). In this paper, we will discuss the basics of redox chemistry and how the human body keeps these in check. We will then discuss what happens when these go awry, focusing mostly on NEC in neonates.

Keywords: necrotizing enterocolitis; neonate; oxidative stress; prematurity; reactive nitrogen species; reactive oxygen species.

Figure 1

Generation of reactive oxygen species in the enterocyte. A diagram illustrating the flow of molecular oxygen to form various radical and non-radical ROS as well as the RNS Peroxynitrite.

Figure 2

Glutathione recycling. A schematic demonstrating the relationship of glutathione reductase and glutathione peroxidase, as well as the recycling of oxidized glutathione to reduced glutathione.