Oxidative Stress and Mitochondrial Dysfunction in Chronic Kidney Disease: From Molecular Mechanisms to Biomarkers and...

Chronic kidney disease (CKD) represents a major global health challenge, affecting more than 10% of the population and contributing substantially to morbidity and premature mortality. Growing evidence identifies oxidative stress and mitochondrial dysfunction as central drivers of renal injury and disease progression across diverse etiologies. The kidney is one of the most mitochondria-rich organs in the body, reflecting the high bioenergetic demands required for tubular reabsorption and metabolic homeostasis. Disruption of mitochondrial oxidative phosphorylation, excessive production of reactive oxygen species (ROS), and impaired mitochondrial quality control mechanisms promote tubular injury, inflammation, and fibrosis. In particular, dysfunction of the electron transport chain, activation of NADPH oxidase isoforms-especially NOX4-and alterations in mitochondrial dynamics create a vicious cycle of oxidative damage and bioenergetic failure. Emerging evidence highlights the importance of mitochondrial quality control pathways, including fusion-fission balance, PINK1/Parkin-mediated mitophagy, and mitochondrial biogenesis regulated by PGC-1α and TFAM. Additional mechanisms include ferroptosis, epigenetic regulation, mitochondrial DNA-mediated innate immune activation, and Na⁺/K⁺-ATPase-linked redox signaling. At the translational level, redox and mitochondrial biomarkers and targeted therapies are biologically compelling, but the evidence is uneven: most candidate biomarkers remain insufficiently standardized, and direct mitochondria-targeted interventions are supported predominantly by preclinical studies or small human proof-of-concept trials. This review therefore emphasizes not only mechanistic advances but also conflicting findings, model limitations, and the barriers that currently separate experimental efficacy from clinically meaningful CKD outcomes.