Cytotoxic and chemotactic potencies of several aldehydic components of oxidised low density lipoprotein for human monocyte-macrophages

We have investigated the cytotoxic and chemotactic potencies of malondialdehyde (MDA), hexanal, 4-hydroxyhexenal (HHE), 4-hydroxynonenal (HNE) and 4-hydroxyoctenal (HOE), which are aldehydes found in oxidised low density lipoprotein (LDL), for human monocyte-macrophages. They were toxic in the following order: hexanal < HHE = HOE < HNE. HNE was toxic at 20 μM and chemotactic at 2.5 μM. The other aldehydes tested had no chemoattractant activity. Our results suggest that HNE arising from LDL oxidation could attract monocytes into the human atherosclerotic lesion. A direct cytotoxic role of aldehydes in foam cell death in the lesion is less likely.