Does iron-driven oxidative stress cause endothelial dysfunction and kidney injury and are higher iron stores linked to worse kidney function?

The claim that iron-driven oxidative stress promotes endothelial dysfunction and renal tubular injury, and that higher iron stores correlate with worse kidney function, is strongly supported by mechanistic, clinical, and genetic evidence.

Mechanistic pathways of injury

Iron-mediated damage is primarily driven by the expansion of the "labile iron pool," which consists of redox-active iron that facilitates Fenton chemistry.

• Endothelial Dysfunction: Excess iron generates hydroxyl radicals that deplete nitric oxide (NO) bioavailability. This occurs through several pathways: the oxidation of dimethylarginine dimethylaminohydrolase II (DDAHII)—which causes the accumulation of asymmetric dimethylarginine (ADMA), a potent eNOS inhibitor—and direct scavenging of NO by superoxide to form peroxynitrite. Structurally, this leads to the downregulation of tight junction proteins like Claudin-5, increasing vascular permeability.
• Renal Tubular Injury: The proximal tubule is highly susceptible to iron-mediated lipid peroxidation. Iron-driven oxidative stress triggers ferroptosis, a regulated cell death pathway characterized by the loss of glutathione peroxidase-4 (GPX4) activity. Additionally, intralysosomal iron can cause lysosomal membrane permeabilization (LMP), releasing proteases that induce mitochondrial depolarization and cell necrosis.

Clinical and population evidence

Population-based studies confirm that elevated iron stores are linked to significant declines in kidney function.

• General and Diabetic Populations: Higher serum ferritin levels are independently associated with an increased risk of incident chronic kidney disease (CKD) and lower estimated glomerular filtration rate (eGFR). Mendelian randomization studies, which use genetic variants as proxies for iron status, suggest a likely causal link, showing a ~30% increased risk of CKD with genetically predicted higher ferritin.
• CKD Progression: In patients with established CKD, the relationship often follows a U-shaped curve. Those in the highest ferritin quartiles face a significantly higher hazard (HR 1.5–1.7) for rapid eGFR decline or kidney failure compared to those in middle quartiles.
• Biomarkers: Renal injury caused by iron is detectable through elevated biomarkers such as Kidney Injury Molecule-1 (KIM-1), Neutrophil Gelatinase-Associated Lipocalin (NGAL), and urinary ferritin light chain (FTL), which often rise before global filtration markers like creatinine.

Bottom line

Iron-driven oxidative stress is a validated driver of both vascular and renal damage. Higher systemic iron stores are robustly associated with an increased risk of developing kidney disease and faster progression toward kidney failure, primarily through mechanisms involving ferroptosis, nitric oxide depletion, and mitochondrial dysfunction.