4-hydroxynonenal: a membrane lipid oxidation product of medicinal interest.

A comprehensive focus on 4-hydroxynonenal (HNE) as candidate molecule in a variety of pathophysiological conditions occurring in humans is here provided. Despite an active, now well characterized, metabolism in most cells and tissues, HNE can be easily detected and quantified by means of several methods, although with different sensitivity. Measurements of HNE and/or stable metabolites in biological fluids are already applied as lipid peroxidation/oxidative stress markers in a huge number of human disease processes, often sustained by inflammatory reactions. A primary involvement of this aldehydic product of membrane lipid oxidation in inflammation-related events, as well as in regulation of cell proliferation and growth, in necrotic or apoptotic cell death, appears supported by its marked ability to modulate several major pathways of cell signaling and, consequently, gene expression. The actual knowledge of HNE reactivity, metabolism, signaling and modulatory effect in the various human organs should provide a solid background to the investigation of the aldehyde's contribution to the pathogenesis of human major chronic diseases and would likely promote advanced and oriented applications not only in diagnosis and prevention but also in molecular treatment of human diseases.