Chronic exposure to ultraviolet (UV) radiation causes oxidative stress, which is involved in photoaging and actinic elastosis. UV and reactive oxygen species generate lipid peroxidation products, including the α, β-unsaturated carbonyl compounds such as acrolein or 4-hydroxynonenal (4-HNE). These aldehydes can modify proteins of the extracellular matrix, but their role in the pathogenesis of photoaging is not clarified. The aim of this study was to investigate whether these aldehydes contribute to alter elastin metabolism and whether topical carbonyl scavengers delay UV-induced skin photoaging. Hairless mice (4-6-week old) daily exposed to UV-A (20 J cm(-2) per day, up to 600 J cm(-2)) exhibited the typical features of photoaging, associated with a significant increase in 4-HNE- and acrolein-adduct content, and elastotic material deposition. Immunofluorescence studies showed the accumulation of 4-HNE adducts on elastin in the dermis of UV-A-exposed mice. This was mimicked in vitro by incubating orcein-elastin with 4-HNE or acrolein, which altered its digestion by leukocyte-elastase, a feature possibly involved in the accumulation of elastotic material. A daily topical application of carnosine completely reversed the development of photoaging alterations and 4-HNE-adduct formation on elastin. These data emphasize the role of 4-HNE and acrolein in the mechanism of photoaging, and the preventive effect of carbonyl scavengers.

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Dietary intake of Opuntia species may prevent the development of cardiovascular diseases. The present study was designed to characterize the biological antioxidant and anti-inflammatory properties of Opuntia species and to investigate whether Opuntia cladodes prevent the development of atherosclerosis in vivo, in apoE(-)KO mice. The effects of the two Opuntia species, the wild Opuntia streptacantha and the domesticated Opuntia ficus-indica, were tested on the generation of intra- and extracellular reactive oxygen species (ROS) production and kinetics of the LDL oxidation by murine CRL2181 endothelial cells and on the subsequent inflammatory signaling leading to the adhesion of monocytes on the activated endothelium and the formation of foam cells. Opuntia species blocked the extracellular ROS (superoxide anion) generation and LDL oxidation by CRL2181, as well as the intracellular ROS rise and signaling evoked by the oxidized LDL, including the nuclear translocation of the transcription factor NFκB, the expression of ICAM-1 and VCAM-1 adhesion molecules, and the adhesion of monocytes to CRL2181. In vivo, Opuntia significantly reduced the formation of atherosclerotic lesions and the accumulation of 4-hydroxynonenal adducts in the vascular wall of apoE-KO mice, indicating that Opuntia cladodes prevent lipid oxidation in the vascular wall. In conclusion, wild and domesticated Opuntia species exhibit antioxidant, anti-inflammatory, and antiatherogenic properties which emphasize their nutritional benefit for preventing cardiovascular diseases.