Overview
Lipid peroxidation is the oxidative degradation of polyunsaturated fatty acids (PUFAs) in cell membranes by reactive oxygen species (ROS). The process generates toxic aldehydes — malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) — that damage proteins, DNA, and mitochondria. When iron-dependent and self-propagating, lipid peroxidation drives ferroptosis — the regulated cell death pathway central to neurodegeneration, CKD, and cancer.
Metal Drivers
Heavy metals are potent initiators of lipid peroxidation:
- Iron: Fe2+ catalyzes Fenton chemistry (Fe2+ + H2O2 → Fe3+ + OH• + OH−), generating hydroxyl radicals that attack membrane PUFAs. This is the basis of ferroptosis [1] [2].
- Nickel: Induces lipid peroxidation in brain tissue, correlating with neurobehavioral deficits [3].
- Cadmium, lead, mercury: All generate ROS and deplete glutathione (the primary endogenous lipid peroxidation defense), amplifying oxidative membrane damage [4] [5].
Microbiome Connection
The gut microbiome modulates lipid peroxidation through:
- Glutathione production: Certain commensals contribute to glutathione synthesis; dysbiosis reduces the antioxidant pool.
- SCFA-mediated protection: Butyrate enhances mitochondrial function and reduces ROS generation.
- Iron ecology: Microbial iron acquisition (siderophores) alters the labile iron pool available for Fenton chemistry.
Cross-References
- ferroptosis — iron-dependent lipid peroxidation-driven cell death
- reactive oxygen species — ROS initiate the peroxidation chain
- glutathione — primary defense against lipid peroxidation
- iron — Fenton chemistry catalyst
- oxidative stress — broader context