Role of Oxidative Stress in Disease Initiation and Progression

Oxidative stress plays a pivotal role in the onset and progression of a wide spectrum of human diseases by disrupting redox homeostasis and promoting cellular and molecular damage. Excessive production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), coupled with inadequate antioxidant defenses, leads to structural and functional alterations in key organs, including the brain, bone, kidney, and liver. In this book, the molecular mechanisms by which OS affects hepatic pathologies like viral hepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), osteoporosis, and neurodegenerative disorders are thoroughly explored. Special focus is placed on transcriptional regulators like Nrf2, FOXO, and HIF-1α, as well as signaling pathways like NF-κB, MAPKs, STAT3, and Wnt/β-catenin. The text emphasizes ROS’s dual function as pathological drivers of tissue damage and remodeling as well as physiological signaling mediators.