Protective Effects of Polyvinylpyrrolidone-Wrapped Fullerene Against Nitric Oxide/Peroxynitrite-Induced Cellular Injury in Human Skin Keratinocytes.

Excess ultraviolet (UV) exposure accelerates skin inflammation, melanogenesis, wrinkle formation, photoaging, and carcinogenesis through oxidative stress and deoxyribonucleic acid damage. These deleterious effects to skin are closely associated with UV-induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced via nitric oxide (NO·) generation. RNS are known to be responsible for various skin disorders, such as erythema, melanin production, reduced barrier function, and psoriasis. These skin disorders are major cosmetic problems; RNS control, in addition to ROS control, is important for maintaining healthy skin. In the present study, we investigated the cytoprotective effects of polyvinylpyrrolidone-entrapped fullerene (C60/PVP), a water-soluble ROS scavenger, against nitric oxide (NO·) and peroxynitrite (ONOO-)-induced human keratinocyte injuries. Protective effects of C60/PVP on NO·/ONOO--induced cellular damage and intracellular ONOO- generation were evaluated using a NO· donor S-nitroso-N-acetylpenicillamine (SNAP) in human skin epidermal HaCaT keratinocytes. Furthermore, the suppressive effect of C60/PVP on UVB-induced generation of intracellular ONOO- levels was also investigated. C60/PVP exerted suppressive effects on intracellular increases in NO·-induced ONOO- generation and subsequent cellular damage. Additionally, C60/PVP significantly decreased the UVB-induced generation of intracellular ONOO- levels. These findings suggest that C60/PVP could be useful as a cosmetics ingredient for prevention of skin injuries and/or dysfunction from NO·/ONOO--induced effects in human skin keratinocytes.

Protective effects of polyvinylpyrrolidone-wrapped fullerene against intermittent ultraviolet-A irradiation-induced cell injury in HaCaT cells.

To identify compounds that suppress UV irradiation-induced oxidative stress in the skin, various types of antioxidants have been studied. Polyvinylpyrrolidone-entrapped fullerene (C60/PVP) is known as a powerful antioxidant that exerts a cytoprotective effect against UV irradiation-induced cell injury in human skin cells and skin models. However, the effects of the alternate attractive C60/PVP feature, persistent antioxidant ability, on cytoprotection have rarely been ascertained. In this study we therefore investigated the efficacies of C60/PVP using an intermittently repeated UVA irradiation model wherein human keratinocytes were repeatedly exposed to UVA five times every 1h and compared the cytoprotective effects with those provided by ascorbic acid-2-O-phosphate-disodium salt (APS) and α-tocopherol (α-Toc). Our results demonstrated that C60/PVP yielded prominent cytoprotective effects against intermittently repeated UVA irradiation-induced injuries in a dose-dependent manner and suppressed intracellular superoxide anion radical (O2(-)) generation both during and after the repeated UVA irradiation. Additionally, C60/PVP also repressed the intermittent UVA irradiation-induced apoptosis via suppression of chromatin condensation and caspase-3/7 activation. Furthermore, the observed cytoprotective effects were superior to the effects of the typical antioxidants APS and α-Toc. These data suggest that C60/PVP might function as a potent cosmetic antioxidant against the effects of repeated and prolonged UVA irradiation through its persistent antioxidative property.

Reduction of conspicuous facial pores by topical fullerene: possible role in the suppression of PGE2 production in the skin.

BACKGROUND: Conspicuous facial pores are therapeutic targets for cosmeceuticals. Here we examine the effect of topical fullerene on conspicuous facial pores using a new image analyser called the VISIA® system. Ten healthy Japanese females participated in this study, and they received applications of 1% fullerene lotion to the face twice a day for 8 weeks. FINDINGS: Fullerene lotion significantly decreased conspicuous pores by 17.6% (p < 0.05, Wilcoxon signed-rank test) after an 8-week treatment. A self-administered questionnaire indicated that this reduction achieved cosmetically appreciable effects. In addition, to investigate the mechanism of effect of fullerene, we examined its effect on UVB-induced prostaglandin E2 (PGE2) production in reconstructed human epidermis (RhE). The results showed that irradiation of RhE with 1000 mJ/cm2 increased PGE2 production by 62.3% (p < 0.05, Mann-Whitney U-test) and the addition of 28 µM fullerene significantly suppressed the UVB-induced PGE2 production by 18.3% (p < 0.05). CONCLUSIONS: Fullerene lotion significantly decreases conspicuous facial pores after an 8-week treatment possibly through the suppression of PGE2 production in the epidermis.

Photoprotective effects of inclusion complexes of fullerenes with polyvinylpyrrolidone.

BACKGROUND: The outermost surface of the body is covered by the stratum corneum, which is critical for proper skin barrier function. We investigated photoprotective effects of inclusion complexes of fullerenes with polyvinylpyrrolidone (PVP/fullerenes). METHODS: To examine the cytoprotective activity of PVP/fullerenes against ultraviolet B (UVB) irradiation, we placed a dish with or without PVP/fullerenes on top of dishes containing cultured keratinocytes with or without PVP/fullerenes. Next, we examined the effects of PVP/fullerenes on the ratio of cells with cornified envelopes and transglutaminase-1 expression by real-time polymerase chain reaction and immunohistochemistry. Finally, we examined the barrier recovery effect of PVP/fullerenes solution by measuring transepidermal water loss after tape stripping in humans. RESULTS: UVB irradiation at 40 mJ/cm(2) markedly induced inhibition of keratinocyte proliferation. The inhibition of keratinocyte proliferation was restored only when PVP/fullerenes were present before UVB irradiation in the lower dish with the cells. UVB irradiation decreased the ratio of cells with cornified envelopes and transglutaminase-1 expression; however, the application of PVP/fullerenes reversed this phenomenon. PVP/fullerenes solution significantly promoted the recovery of transepidermal water loss on the second and third days after tape stripping. CONCLUSION: PVP/fullerenes can be used in cosmetics, especially in those intended to protect photo damage and ameliorate skin barrier perturbations.