4-Hydroxy-2-nonenal, a specific lipid peroxidation product, is elevated in lungs of patients with chronic obstructive pulmonary disease.

Cigarette smoking results in oxidative stress and inflammation in the lungs, which are involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). 4-Hydroxy-2-nonenal (4-HNE), a highly reactive diffusible product of lipid peroxidation, is a key mediator of oxidant-induced cell signaling and apoptosis. 4-HNE has a high affinity toward cysteine, histidine, and lysine groups and forms direct protein adducts.