Oxidative Stress in Keratoconus Publisher



Abdi P¹ ; Aminizadeh M¹
Source: Keratoconus: Optical and Surgical Management Published:2024

Abstract

Free radicals are by-products of normal cellular processes and are a mandatory component in normal physiological activities. These oxidants include reactive oxygen species (ROS) and reactive nitrogen species (RNS).1, 2 In the normal redox state, ROS are involved in cellular growth and proliferation, signal transduction, gene expression, immune defence mechanisms, and apoptosis.3–5 Mitochondria is the major source of endogenous ROS through an oxidative phosphorylation chain which takes place in the inner membrane. Other endogenous sources include peroxisomes and microsomes, NADPH oxidase, cytochrome P450, xanthine oxidase, and nitric oxide synthase (NOS). ROS and RNS may also be produced exogenously after exposure to ultraviolet (UV) and ionizing radiation, and chemical agents. In the presence of iron, hydroxide and hydroxyl radicals are produced through Fenton and Haber–Weiss reactions.6–8 © 2025 selection and editorial matter, Mehrdad Mohammadpour and Masoud Khorrami-Nejad; individual chapters, the contributors.