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Klass B.R.,RAFT Institute | Branford O.A.,Institute for Plastic Surgery and Education | Grobbelaar A.O.,Institute for Plastic Surgery and Education | Rolfe K.J.,RAFT Institute
Wound Repair and Regeneration | Year: 2010

Dermal fibrosis, or scarring, following surgical incisions, traumatic wounds and burns presents a major clinical burden. Transforming growth factor (TGF)-β1 is a major factor known to stimulate fibroblast proliferation, collagen production, and the differentiation of fibroblast to myofibroblast promoting wound contraction. Furthermore, excessive or prolonged TGF-β1 has been shown to be associated with scarring. Green tea contains high amounts of polyphenols with the major polyphenolic compound being epigallocatechin-3- gallate (EGCG). EGCG has been shown to be anti-inflammatory, anti-oxidant, and may improve wound healing and scarring, though its precise effect on TGF-β1 remains unclear. This study aimed at determining the effect of EGCG on TGF-β1 collagen contraction, gene expression and the differentiation of fibroblast to myofibroblast. EGCG appears to affect the role that TGF-β1 plays in fibroblast populated collagen gel contraction and this seems to be through both myofibroblast differentiation and connective tissue growth factor gene expression and reduces the expression of collagen type I gene regulation. © 2009 by the Wound Healing Society. Source


Haywood R.,RAFT Institute | Volkov A.,RAFT Institute | Andrady C.,RAFT Institute | Sayer R.,Croda Europe Ltd
Free Radical Research | Year: 2012

The in vitro star system used for sunscreen UVA-testing is not an absolute measure of skin protection being a ratio of the total integrated UVA/UVB absorption. The in vivo persistent-pigment-darkening method requires human volunteers. We investigated the use of the ESR-detectable DMPO protein radical-adduct in solar-simulator-irradiated skin substitutes for sunscreen testing. Sunscreens SPF rated 20+ with UVA protection, reduced this adduct by 4065% when applied at 2 mg/cm 2. SPF 15 Organic UVA-UVB (BMDBM-OMC) and TiO 2-UVB filters and a novel UVA-TiO 2 filter reduced it by 21, 31 and 70% respectively. Conventional broad-spectrum sunscreens do not fully protect against protein radical-damage in skin due to possible visible-light contributions to damage or UVA-filter degradation. Anisotropic spectra of DMPO-trapped oxygen-centred radicals, proposed intermediates of lipid-oxidation, were detected in irradiated sunscreen and DMPO. Sunscreen protection might be improved by the consideration of visible-light protection and the design of filters to minimise radical leakage and lipid-oxidation. © 2012 Informa UK, Ltd. Source


Haywood R.,RAFT Institute | Andrady C.,RAFT Institute | Kassouf N.,RAFT Institute | Sheppard N.,RAFT Institute
Photochemistry and Photobiology | Year: 2011

Skin can be exposed to high-intensity UV-radiation in hot countries and during sunbed use; however, the free-radical damage at these intensities is unknown. We used electron spin resonance spectroscopy to measure free-radical generation in ex vivo human skin/substitutes +/- the spin-trap 5,5 dimethyl-1-pyrroline N-oxide (DMPO) exposed to solar-irradiation equivalent to Mediterranean sunlight. Skin-substitutes, model DNA-photosensitizer systems, lipids and proteins were also irradiated with low-intensity UVA/visible light. Without DMPO a broad singlet was detected (using both irradiations) in skin/substitutes, nail-keratin, tendon-collagen, phospholipid and DNA + melanin or riboflavin. In addition to lipid-derived (tentatively tert-alkoxyl/acyl-) and protein radicals detected with DMPO at lower intensities, isotropic carbon-, additional oxygen- and hydrogen-adducts were detected in solar-irradiated skin/substitutes at higher intensities. Carbon-adducts were detected in UVA-irradiated human skin cells, DNA + melanin or riboflavin and soybean-phospholipid. Anisotropic protein-adducts, comparable to adducts in solar-irradiated tendon-collagen, were absent in UVA-irradiated skin fibroblasts suggesting the trapping of extracellular collagen radicals. Absence of hydrogen-adducts in fibroblasts implies formation in the extracellular compartment. We conclude damage at high intensities is part cellular (carbon- and oxygen-radicals) and part extracellular (protein- and hydrogen/H+ + e-), and skin substitutes are suitable for sunscreen testing. While UVA absorption and lipid-oxidation is direct, DNA and protein-oxidation require photosensitisation. © 2010 The American Society of Photobiology. Source

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