## Copper-Induced Hepatocellular Injury Mechanism ### Primary Mechanism: Oxidative Stress **Key Point:** Accumulated copper catalyzes the formation of reactive oxygen species (ROS) via Fenton-like reactions, overwhelming hepatic antioxidant defenses and causing lipid peroxidation, protein oxidation, and DNA damage. ### Biochemical Pathway 1. **Fenton Reaction:** Cu^2+^ + H~2~O~2~ → Cu^+^ + OH• + OH^−^ 2. **Haber-Weiss Cycle:** Copper cycles between Cu^2+^ and Cu^+^ states, continuously generating hydroxyl radicals 3. **Lipid Peroxidation:** ROS attack polyunsaturated fatty acids in hepatocyte membranes 4. **Mitochondrial Dysfunction:** Oxidative damage to mitochondrial membranes → impaired energy production 5. **Apoptosis & Necrosis:** Overwhelming oxidative stress triggers hepatocyte death ### Histopathological Consequences - Acute hepatitis (in fulminant presentations) - Cirrhosis (in chronic copper accumulation) - Steatosis (lipid peroxidation and impaired fat export) - Mallory-Denk bodies (misfolded proteins from oxidative damage) **High-Yield:** Copper is a redox-active metal (unlike iron, which is also redox-active but handled differently). This redox cycling is the KEY to copper's toxicity. **Clinical Pearl:** The severity of liver injury correlates with hepatic copper content. Penicillamine and zinc therapy work by reducing free copper availability and preventing ROS generation. **Mnemonic:** **COPPER TOXICITY = ROS** — Reactive Oxygen Species are the primary culprit, not direct enzyme inhibition. [cite:Harrison 21e Ch 356] 
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