Article

Use of the synthetic superoxide dismutase/catalase mimetic EUK-134 to compensate for seasonal antioxidant deficiency by reducing pre-existing lipid peroxides at the human skin surface

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Abstract

The generation of reactive oxygen species (ROS) in UV-exposed skin is believed to contribute to the photoaging process. The stratum corneum (SC) contains a variety of enzymatic and non-enzymatic antioxidants to protect against various environmental sources of free radicals. We have previously shown a seasonal variation in SC catalase activity with strong deactivation in sun-exposed skin in the summer, whereas SC superoxide dismutase (SOD) activity remained intact in those conditions. This potentially leads to the local overproduction of H2O2. The oxidized lipid squalene hydroperoxide accumulates at the surface of sun-exposed skin in the summer and upon exposure to ultravoilet A (UVA) doses as low as 0.1 J cm-2 and adequate protection against excessive lipid peroxidation at times of UV exposure should be aimed for. We have been using the induction of lipid hydroperoxides at the skin surface by a single dose of UVA (1 J cm-2) as a model system to evaluate the protective effect of antioxidants in vivo. Topical treatment with the synthetic SOD/catalase mimetic molecule (EUK-134) 1 h before UVA exposure reduced the level of lipid peroxides at the surface of UVA-exposed skin but also baseline peroxide levels on non-irradiated skin were reduced in a dose-dependent fashion. In contrast to alpha-tocopherol, EUK-134 even reduced the level of lipid peroxides at the surface of UVA-exposed skin when it was applied after irradiation. We confirmed that this salen-manganese complex was able to reduce squalene hydroperoxide levels in vitro, suggesting peroxidase-like activity towards organic peroxides. These data support the concept that the synthetic SOD/catalase mimetic EUK-134 might be able to compensate for seasonal deficiencies in antioxidant defense capacity at the skin surface, thereby contributing to an optimal protection of the skin against the accumulation of oxidative damage.

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... 3). As suggested by Declercq et al. (2004), a catalase mimetic like EUK-134 might also be considered to maintain catalase like activity. Data inFig. ...
... We showed that the catalase activity in human stratum corneum decreased on a chronically sun exposed site as a function of age (Fig. 1). It is known that UVA-irradiation dramatically decreases enzymatic activity of catalase in vitro and in stratum corneum (Declercq et al., 2004; Hellemans et al., 2003). Samples analysed here were collected on skin that was not recently exposed to UV irradiation , hence a direct photo-inactivation of catalase is improbable. ...
... We showed an inactivation of catalase under similar conditions. As suggested by Declercq et al. (2004), compensation for the loss of enzymatic antioxidant activity can be offered by a UV stable SOD/catalase mimetic such as EUK-134. We additionally showed that catalase like activity of EUK- 134 was not affected by peroxynitrite (Fig. 4), suggesting that this compound may not only be useful during or after UV stress but may also offer antioxidant protection to the skin under inflammatory conditions. ...
Article
Skin ageing is a complex biological process related to a decline in physiological and biochemical performance. A decline in the mitochondrial energy production is a feature of ageing at the cellular level. This is partially attributed to excessive production of reactive oxygen species such as superoxide and hydrogen peroxide in aged individuals. We have investigated the effect of (glyc)oxidative stress on two biochemical targets relevant for the energy metabolism of the skin. First, we showed an age dependent decline in the activity of the hydrogen peroxide detoxifying antioxidant catalase in stratum corneum on a chronically sun-exposed site. Furthermore catalase was sensitive to peroxynitrite-induced in vitro inactivation. Catalase mimetics as well as peroxynitrite scavengers are proposed to maintain hydrogen peroxide detoxification pathways. The second target was creatine kinase, an enzyme that controls the creatine-creatine phosphate shuttle. Creatine kinase lost activity after in vitro glycation by methylglyoxal. This activity loss could be prevented by antiglycation actives. These data suggest that biomolecules involved in energy homeostasis become damaged by different sources of stress. Actives specifically selected for optimal protection against these stress situations will decrease skin vulnerability and prevent the premature loss of skin function.
... The most common animal model is that of rats and different types of mice, but in addition to these and the mentioned nematodes, studies were also carried out on pigs, sheep, or fish or by using the vinegar fly. Additionally, there are also studies of the protective effect against induced oxidative stress in other models than animals, like E. coli [11], and in humans, with an evaluation of the beneficial effects over ultraviolet A-exposed skin in vivo [12]. ...
... The three manganosalen complexes reduced anti-donor cytotoxic responses in skin-grafted mice, and they decreased pro-inflammatory type 1 alloresponse while promoted anti-inflammatory type 2 alloimmunity. Declercq et al. [12] carried out a study of the protective effects of EUK-134 on the human skin of 748 healthy volunteers (18-80 years of age) over a period of 4 years. EUK-134 had been previously reported to increase cell survival in normal human keratinocytes upon exposure to ultraviolet-B, superoxide, or hydrogen peroxide [141,142]. ...
Article
Full-text available
Manganosalen complexes are coordination compounds that possess a chelating salen-type ligand, a class of bis-Schiff bases obtained by condensation of salicylaldehyde and a diamine. They may act as catalytic antioxidants mimicking both the structure and the reactivity of the native antioxidant enzymes active site. Thus, manganosalen complexes have been shown to exhibit superoxide dismutase, catalase, and glutathione peroxidase activities, and they could potentially facilitate the scavenging of excess reactive oxygen species (ROS), thereby restoring the redox balance in damaged cells and organs. Initial catalytic studies compared the potency of these compounds as antioxidants in terms of rate constants of the chemical reactivity against ROS, giving catalytic values approaching and even exceeding that of the native antioxidative enzymes. Although most of these catalytic studies lack of biological relevance, subsequent in vitro studies have confirmed the efficiency of many manganosalen complexes in oxidative stress models. These synthetic catalytic scavengers, cheaper than natural antioxidants, have accordingly attracted intensive attention for the therapy of ROS-mediated injuries. The aim of this review is to focus on in vivo studies performed on manganosalen complexes and their activity on the treatment of several pathological disorders associated with oxidative damage. These disorders, ranging from the prevention of fetal malformations to the extension of lifespan, include neurodegenerative, inflammatory, and cardiovascular diseases; tissue injury; and other damages related to the liver, kidney, or lungs.
... The most common animal model is that of rats and different types of mice, but in addition to these and the mentioned nematodes, studies were also carried out on pigs, sheep, fish or using the vinegar fly. Additionally there are also studies of protective effect against induced oxidative stress in other models than animals, like E. Coli [11] and also in humans with an evaluation of the beneficial effects over UVA-exposed skin in vivo [12] . ...
... Declercq et al [12] carried out a study of the protective effects of EUK-134 on the human skin of 748 healthy volunteers (18-80 years of age) over a period of 4 years. EUK-134 had been previously reported to increase cell survival in normal human keratinocytes upon exposure to ultraviolet-B, superoxide or hydrogen peroxide [145][146]. ...
Preprint
Full-text available
Manganosalen complexes are coordination compounds that possess a chelating salen-type ligand, a class of bis-Schiff bases obtained by condensation of salicylaldehyde and a diamine. They may act as catalytic antioxidants mimicking both the structure and the reactivity of the native antioxidant enzymes active site. Thus, manganosalen complexes have shown to exhibit superoxide dismutase, catalase, and glutathione peroxidase activities, and they could potentially facilitate the scavenging of excess ROS, thereby restoring the redox balance in the damaged cells and organs. Initial catalytic studies compared the potency of these compounds as antioxidants in terms of rate constants of the chemical reactivity against ROS, giving catalytic values approaching and even exceeding that of the native antioxidative enzymes. Although most of these catalytic studies lack of biological relevance, subsequent in vitro studies have confirmed the efficiency of many manganosalen complexes in oxidative stress models. These synthetic catalytic scavengers, cheaper than natural antioxidants, have accordingly attracted intensive attention for the therapy of ROS-mediated injuries. The aim of this review is to focus on in vivo studies performed on manganosalen complexes and their activity on the treatment of several pathological disorders associated with oxidative damage. This disorders, ranging from the prevention of fetal malformations to the extension of lifespan, include neurodegenerative, inflammatory and cardiovascular diseases, tissue injury, and other damages related to liver, kidney or lungs.
... P53 is well known to accumulate following various types of environmental stresses, including DNA-damaging agents, decreased oxygen, and heat shock, and redox stress [11]. Declercq et al. [12] recently supported the concept that the synthetic SOD/catalase mimetic EUK-134 might be able to compensate for seasonal deficiencies in the antioxidant defense capacity at the skin surface, thereby contributing to an optimal protection of the skin against the accumulation of oxidative damage and confirming previously published results from Decraene et al. about the protective effects EUK-134 on human keratinocytes [12]. ...
... P53 is well known to accumulate following various types of environmental stresses, including DNA-damaging agents, decreased oxygen, and heat shock, and redox stress [11]. Declercq et al. [12] recently supported the concept that the synthetic SOD/catalase mimetic EUK-134 might be able to compensate for seasonal deficiencies in the antioxidant defense capacity at the skin surface, thereby contributing to an optimal protection of the skin against the accumulation of oxidative damage and confirming previously published results from Decraene et al. about the protective effects EUK-134 on human keratinocytes [12]. ...
Article
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The history of cosmetics develops in parallel to the history of man, associated with fishing, hunting, and superstition in the beginning, and later with medicine and pharmacy. Over the ages, together with human progress, cosmetics have changed continuously and nowadays the cosmetic market is global and highly competitive, where terms such as quality, efficacy and safety are essential. Consumers’ demands are extremely sophisticated, and thus scientific research and product development have become vital to meet them. Moreover, consumers are aware about environmental and sustainability issues, and thus not harming the environment represents a key consideration when developing a new cosmetic ingredient. The latest tendencies of cosmetics are based on advanced research into how to interfere with skin cell aging: research includes the use of biotechnology-derived ingredients and the analysis of their effects on the biology of the cells, in terms of gene regulation, protein expression and enzymatic activity measures. In this review, we will provide some examples of cosmetic active ingredients developed through biotechnological systems, whose activity on the skin has been scientifically proved through in vitro and clinical studies.
... Significant decrease in human keratinocytes deaths after exposure to UV radiation, hydrogen peroxide and other pe roxides was observed (38). Topically applied EUK-134 in vivo results in the decrease in lipid peroxidation (studies on squalene oxidation to its monohydroperooxide) on the surface of skin exposed to UVA radiation, also in case of application of EUK-l 34 after skin irradiation (39) . No data however can be found on the abi lity of EUK-134 to penetrate into the stratum corneum a nd livi ng layers of the skin , but it seems possible if the molec ular weight is considered. ...
... Fig. 4 S1ruc111re of EUK-8 a11d EUK-134 si11111/a1i11g SOD!cawlase system activiry (39). ...
Article
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Free radicals are the most dangerous species responsible for unfavourable reactions and undesired processes in the skin. They are also the reason of premature skin ageing. Free radicals are formed in normal conditions during natural biological processes such as melanogenesis or cell breathing, but they can be also released following exogenic factors activity. The most dangerous is UV radiation. Human skin possesses its own protective mechanisms against free radicals. The best known are vita- min E and vitamin C and both are widely used in cosmetics. Metals, although less known, are the very important factors preventing from free radicals, as well. They can act directly as bound in the active centres of several enzymes or in indirect way. Among enzymes of antiradical properties there are superoxide dismutase containing zinc and copper (SOD1) or manganese (SOD2) in mitochondria, as well as selenium containing glutathione peroxidase. Metals can act also in indirect way. Zinc for example stabilizes cell membranes. It protects against other redox active metals (Cu1+, Fe2+ through exchanging them in the cell membranes, stimulates metalothionein synthesis - the very important antioxidative molecule, and finally it can participate in vitamin E metabolism, although its activity in this process was not thoroughly studied. The use of metals as active agents in cosmetics is not well recognized. They are usually used as antibacterial compounds. Their usage as antioxidants is however quite new. Recently, i.e. superoxide dismutase was started to be used in cosmetics products. This allows to believe for the future development of metal use in cosmetic goods as important antioxidant agents.
... In other words, is Mn salen transporting Mn into the cell and is it the active species? Currently, the Mn III salen, EUK134, is used in cosmetic skin preparations by Estee Lauder, as its SOD/catalase activity is able to compensate for seasonal deficiencies in antioxidant defense capacity at the skin surface, thereby contributing to optimal protection of the skin against the accumulation of oxidative damage.356 Manganese(III) corroles are the most common form of stable Mn-corrole complexes.The first corrole syntheses were performed in the 1960s motivated by natural occurrence of cobalamin (vitamin B12, which is a corrin (a reduced type of corrole). ...
Thesis
The intracellular imbalance between antioxidants and pro-oxidants is involved in the development of many pathologies (like chronic inflammatory bowel diseases-IBD). The fact that manganese superoxide dismutase (MnSOD) is the first line of antioxidant defense led us to study the role of MnSOD mimics as anti-inflammatory agents in the context of IBD. Mn1 is easily synthesized, stable, with good intrinsic anti-superoxide activity and anti-inflammatory activity on intestinal epithelial cells (HT29-MD2). The presence of intact Mn1 (ligand+Mn2+) inside HT29-MD2, created to study intestinal inflammation, was demonstrated using mass spectrometry (IMSMS). After 6h of incubation with 100 µM Mn1 and with LPS 0.1 µg/mL, Mn1 was detected intact with an estimated intracellular concentration of 10 µM. Using the OcSILAC strategy, making possible to simultaneously quantify protein expression and oxidation at the proteome-wide cysteine level, it has been demonstrated that an oxidation was induced by LPS from 15min (in the organelles fraction, including mitochondria) and was resolved after 6h-LPS, with an overexpression of MnSOD (after 3h). When coincubated with LPS, Mn1 limited the total protein oxidation at 15min (70% in the membranes/organelles) and compensate for MnSOD at 6h. Mn1 also restored to their basal levels most of the proteins that were under and overexpressed upon LPS activation. Our results thus demonstrate the potential of Mn1 as a new therapeutic agent against IBD.
... The suspension was cooled in an ice/water bath and then filtered; the brown solid was washed with water and acetone to give the final product in 70% yield. The concentration of EUK-134 was determined from the absorption spectrum [45,47] and its elemental analysis, ultraviolet-visible absorbance spectrum, infrared spectrum, SOD activity, catalase activity, peroxidase activity, 1 H NMR spectrum and so on were consistent with the reported structure and the previous data. [48] Eight-Arm Radial Maze Test ...
... In the current study, we employ the synthetic superoxide dismutase/catalase (SOD/CAT) mimetic EUK-134 as an extracellular antioxidant source and examine its synergistic effect with exercise on ROS relief. This antioxidant can function as supplemental SOD/CAT to neutralize O 2 − and H 2 O 2 and reduce oxidative stress in worms [35]. ...
Article
Full-text available
Antioxidant uptake and regular exercise are two well-acknowledged measures used for rejuvenation and oxidative stress elimination. Previous studies have revealed that moderate exercise mildly increases intracellular signaling oxidant levels and strengthens the ability of an organism to deal with escalating oxidative stress by upregulating antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase. Antioxidant supplementation directly scavenges intracellular reactive oxygen species (ROS) to reduce oxidative stress. However, research to understand the impacts of these enzymes on mitigating oxidative stress from the perspective of simple animals is limited. Herein, we show that exercise combined with antioxidant supplementation ameliorates the physiological phenotypes and markers of aging in wild-type and SOD/CAT-deficient Caenorhabditis elegans . We discovered that treated wild-type and gene-deficient worms show better survivorship, reproduction, and motility compared with their control counterparts. Assays of biochemical indices revealed that variations in sod-3 expression under different stress levels imply an inducible enzyme response resulting from exercise training and antioxidant supplementation. In addition, induced ROS resistance obtained from any type of treatment could persist for several days even after treatment cessation, thus suggesting a potential long-term antioxidative stress effect. Our findings confirm that exercise, antioxidant supplementation, and their combination could significantly improve the ability of C . elegans to withstand adverse stress. Our observations provide promising insights into future therapies of anti-oxidative stress in higher animals.
... Similar to our cheek samples, Ryu et al. [83] reported increased expression of glutathione S transferase 1 and peroxiredoxin 2 in psoriatic skin as was also shown for dandruff SC. Declercq et al. [84] have previously reported decreased catalase in the SC in the summer months of the year clearly as a result of UV stress similar to our samples. Protein deglycase DJ-1 was also increased on the cheek which is known to be elevated in UV-induced skin damage [85]. ...
Article
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Background: The effect of photodamage on facial stratum corneum (SC) is still poorly understood. Objective: To describe the SC proteome from tape strippings of Caucasian SC from photoexposed cheek and photoprotected post auricular (PA) site a global analysis of photodamage on the skin will be developed leading to a better understanding of keratinocyte signalling pathways and identification of new molecular targets for the treatment of photoaged skin. Methods: Female Caucasian subjects had 9 consecutive tape strippings taken from their cheeks and PA site. Proteins were extracted and the trypsin digested peptides were analyzed by nanochromatography coupled to a high-resolution mass spectrometer. Data dependent acquisition allowed protein identification that was processed by Paragon algorithm of Protein Pilot software. Results: Changes in the levels of epidermal differentiation proteins were apparent indicating poor epidermal differentiation and SC maturation (keratins, cornified envelope (CE) proteins) on photoexposed cheeks. Differences in protease-antiprotease balance were observed for corneodesmolysis (favouring desquamation) and filaggrinolysis (favouring reduced filaggrin processing). 12R-LOX, a CE maturation enzyme, was reduced in photodamaged skin but not transglutaminases. Changes in signal keratinocyte transduction pathway markers were demonstrated especially by reduced levels of downstream signalling markers such as calreticulin (unfolded protein response; UPR) and increased level of stratifin (target of rapamycin; mTOR). Evidence for impaired proteostasis was apparent by reduced levels of a key proteasomal subunit (subunit beta type-6). Finally, key antioxidant proteins were upregulated except catalase. Conclusion: Clear examples of poor keratinocyte differentiation and associated metabolic and signalling pathways together with reduced SC maturation were identified in photodamaged facial SC. Corneocyte immaturity was evident with changes in CE proteins. Particularly, the reduction in 12R-LOX is a novel finding in photodamaged skin and supports the lack of SC maturation. Moreover, filaggrinolysis was reduced, whereas corneodesmolysis was enhanced. From our results, we propose that there is a poor crosstalk between the keratinocyte endoplasmic reticulum UPR, proteasome network and autophagy machinery that possibly leads to impaired keratinocyte proteostasis. Superimposed on these aberrations is an apparent enhanced mTOR pathway that also contributes to reduced SC formation and maturation. Our results clearly indicate a corneocyte scaffold disorder in photodamaged cheek SC. This article is protected by copyright. All rights reserved.
... However, EUK-189 and EUK-207 can be formulated into topical preparations that reduce ear infl ammation in the mouse (Doctrow et al., unpublished data). Furthermore, topical application of an EUK-134 preparation to the skin of human volunteers prevented skin lipid peroxidation caused by UVA exposure [ 70 ]. Such data support the future testing of topical preparations of salen Mn complexes to mitigate cutaneous radiation injury. ...
Chapter
Salen Mn complexes, including EUK-134, EUK-189, and the cyclized analog EUK-207, are synthetic SOD/catalase mimetics that have beneficial effects in many models of oxidative stress. As oxidative stress has been implicated by some investigators in delayed radiation injury, we are investigating whether these compounds can mitigate injury to normal tissues caused by ionizing radiation. This review describes some of this research, focusing on several tissues of interest, including the lung, kidney, and skin. These studies have demonstrated suppression of delayed radiation injury in animals treated with EUK-189 and/or EUK-207. While an antioxidant mechanism of action is postulated, it is likely that the mechanisms of radiation mitigation by these compounds in vivo are complex and may involve non-redox-related mechanisms and differ in various target tissues. It is notable, however, that indicators of oxidative stress are increased in lung and skin radiation injury models, and suppressed by salen Mn complexes. Furthermore, histological, gene expression, and other assessments suggest that salen Mn complex treatment promotes a more normalized tissue environment in irradiated animals, including preservation of microvasculature in the skin and lung. In certain experimental models, including irradiated cell cultures, salen Mn complexes have shown “mito-protective” properties, that is, attenuating mitochondrial injury. In summary, salen Mn complexes could be useful to mitigate delayed radiation injury to normal tissues following radiation therapy, accidental exposure, or radiological terrorism. Optimizing their mode of delivery and other key pharmaceutical properties, as well as gaining more understanding of their mechanism(s) of action as radiation mitigators, are key issues for future study.
... Herein, EUK134 was reported as an effective combination catalase/ SOD mimetic. In particular, topical treatment with EUK134 shortly before ultraviolet A (UVA) exposure resulted in reduced levels of lipid peroxides at the surface of UVAexposed skin, but also baseline peroxide levels on nonirradiated skin were reduced in a dose-dependent manner (20). As inhibition of H 2 O 2 signaling using an EUK134-like compound has already been shown to be a promising approach, for example, to breast cancer therapy it might also be possible that the protective effect of SOD1 and/or EUK134 on counteracting radiation-induced EC loss could be mediated by H 2 O 2 decomposition (71). ...
Article
Aims: Radiation-induced normal tissue toxicity is closely linked to endothelial cell (EC) damage and dysfunction (acute effects). However, the underlying mechanisms of radiation-induced adverse late effects with respect to the vascular compartment remain elusive and no causative radioprotective treatment is available to date. Results: The importance of injury to EC for radiation-induced late toxicity in lungs after whole thorax irradiation (WTI) was investigated using a mouse model of radiation-induced pneumopathy. We show that WTI induces EC loss as long-term complication which is accompanied by the development of fibrosis. Adoptive transfer of MSCs either derived from bone marrow or aorta (vascular wall-resident MSCs) in the early phase after irradiation limited the radiation-induced EC loss and fibrosis progression. Furthermore, MSC-derived culture supernatants rescued the radiation-induced reduction in viability and long-term survival of cultured lung EC. We further identified the antioxidant enzyme superoxide dismutase 1 (SOD1) as MSC-secreted factor. Importantly, MSC-treatment restored the radiation-induced reduction of SOD1 levels after WTI. A similar protective effect was achieved by using the SOD-mimitic EUK134 suggesting that MSC-derived SOD1 is involved in the protective action of MSC presumably though paracrine signaling. Innovation: Here we explored the therapeutic potential of mesenchymal stem cell (MSC) therapy to prevent radiation-induced EC loss (late effect) and identified the protective mechanisms of MSC action. Conclusions: Adoptive transfer of MSCs early after irradiation counteracts radiation-induced vascular damage and EC loss as late adverse effects. The high activity of vascular wall-derived MSCs for radioprotection may be due to their tissue-specific action.
... Ultraviolet radiation is responsible for generating various reactive oxygen species, such as hydrogen peroxide and singlet oxygen [101,114]. Likewise, a decrease in antioxidant catalase has been observed in the hydrogen peroxide detoxification in the cornified layer of chronically sun-exposed skin [115], mainly due to UVA irradiation [116,117], as well as in creatine kinase activity. The loss of this activity could be prevented by antiglycation actives [115]. ...
Chapter
Skin, which is in continuous evolution throughout our lifetime, suffers changes with age and may develop malignancies. The part of the skin most involved in its biomechanical functions is the dermis. The knowledge of the histopathological changes that occur in the dermis with age is essential to develop regenerative or aesthetic techniques which will minimize or delay the effects of cutaneous aging from a physiological point of view. During embryogenesis, the dermis undergoes changes as the amount of collagen and elastic fibers increases and it becomes less cellular. It is in the dermal-epidermal junction where the major alterations with age occur. Together with that fact, the dermis changes are crucial in cutaneous aging, resulting in the loss of its biomechanical properties. The dermis becomes thinner, more acellular and avascular, while collagen, elastin and ground substance are altered, and cutaneous appendages decrease. Elastic fibers decrease in number and size in the papillary dermis, which shows signs of elastolysis. The fibroblasts show an altered metabolism by reducing their lifespan, number and their capacity to produce collagen and to divide. All this give rise to elongated collagen fibrils, provoking the loss of skin elasticity. Collagen fibers are increasingly fragmented and disorganised, diminishing the overall percentage of type I and III collagen. The bundles of collagen become thicker and stiffer, especially in the reticular dermis. All these alterations make the skin less stretchable, less resilient and, therefore, physiologically prone to wrinkling - changes that are known as the Net effect. Along with this, several external agents provoke early skin aging, such as smoking or, particularly, ultraviolet radiation, which damages the collagen and elastic fibers and hinders the development of elastosis and telangiectasias. Photoaging consists of the destruction of fibers in the papillary dermis, with a corresponding increase in intercellular substance and moderate inflammatory infiltrate. In the chapter, we will analyze in detail the main histological changes that take place in the different elements of the dermis as a result of aging, and look at the cellular and histological basis of certain antiaging skin treatments which target the dermis. For this, we bring together the information that exists on this topic, providing researchers and dermatologists with rapid access to current knowledge concerning the mechanisms which explain, at cellular and tissular level, part of their deterioration with age.
... Based on the elevated proneness of SQ to photodecomposition , and the many biological effects of UV-induced SQ peroxides it has been recently reproposed that these reactive by-products may be principal physiological molecular mediators of the biological effects of UV irradiation and other pro-oxidants targeting skin [39]. As described above, the protective effects of SQ are counterbalanced by the generation, by the same peroxidative mode, of low-molecular weight and relatively hydrosoluble reactive species [57, 58], chemically derived from the antioxidant action of the triterpene. These by-products are able to diffuse from the skin outer corneum mantel into viable layers and hence target keratinocyte plasma membrane PUFA, thereby causing arachidonic acid decrease and a sequel of consequent biological effects, including the production of a cascade of lipid oxidation reactive nucleophiles, such as 4-hydroxy-2 nonenal (4-HNE). ...
Article
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Skin surface lipid (SSL) film is a mixture of sebum and keratinocyte membrane lipids, protecting skin from environment. Its composition is unique for the high percentage of long chain fatty acids, and of the polyterpenoid squalene, absent in other human tissues, and in non-human Primates sebum. Here, the still incomplete body of information on SSL as mediators of external chemical, physical, and microbial signals and stressors is revised, focusing on the central event of the continuous oxidative modification induced by the metabolic activity of residential and pathological microbial flora, natural or iatrogenic UV irradiation, exposure to chemicals and cosmetics. Once alpha-tocopherol and ubiquinol-10 antioxidant defences of SSL are overcome, oxidation of squalene and cholesterol gives rise to reactive by-products penetrating deeper into skin layers, to mediate local defensive inflammatory, photo-protective, immune reactions or, at higher concentrations, inducing local but also systemic immune depression, ultimately implicating skin cancerogenesis. Qualitative modifications of SSL represent a pathogenetic sign of diagnostic value in dermatological disorders involving altered sebum production, like pytiriasis versicolor, acne, atopic or seborrheic dermatitis, as well as photo-aging. Achievements of nutriceutical interventions aimed at restoring normal SSL composition and homeostasis are discussed, as feasible therapeutic goals and major means of photo-protection.
... Vector-mediated CAT over-expression in human reconstructed skin reduced UVA and UVB alterations, particularly 8-OH-G formation, sunburn cell production, caspase-3 activation and p53 accumulation (Rezvani et al. 2006b). Pre-treatment with the synthetic SOD/CAT mimetic molecule (EUK-134) followed by a single dose of UVA reduced the level of lipid peroxides at the surface of UVA-exposed skin and baseline peroxide levels on non-irradiated skin were also reduced in a dosedependent fashion (Declercq et al. 2004). Topically administered SOD has been also shown to prevent acute cutaneous toxicity in oncologic patient radiotherapy (Manzanas García et al. 2008). ...
Article
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Solar energy has a number of short- and long-term detrimental effects on skin that can result in several skin disorders. The aim of this review is to summarise current knowledge on endogenous systems within the skin for protection from solar radiation and present research findings to date, on the exogenous options for such skin photoprotection. Endogenous systems for protection from solar radiation include melanin synthesis, epidermal thickening and an antioxidant network. Existing lesions are eliminated via repair mechanisms. Cells with irreparable damage undergo apoptosis. Excessive and chronic sun exposure however can overwhelm these mechanisms leading to photoaging and the development of cutaneous malignancies. Therefore exogenous means are a necessity. Exogenous protection includes sun avoidance, use of photoprotective clothing and sufficient application of broad-spectrum sunscreens as presently the best way to protect the skin. However other strategies that may enhance currently used means of protection are being investigated. These are often based on the endogenous protective response to solar light such as compounds that stimulate pigmentation, antioxidant enzymes, DNA repair enzymes, non-enzymatic antioxidants. More research is needed to confirm the effectiveness of new alternatives to photoprotection such as use of DNA repair and antioxidant enzymes and plant polyphenols and to find an efficient way for their delivery to the skin. New approaches to the prevention of skin damage are important especially for specific groups of people such as (young) children, photosensitive people and patients on immunosuppressive therapy. Changes in public awareness on the subject too must be made.
... There is much evidence to support MMP family actively involved in skin photoaging process [18][19][20] and some antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase also contributing to this process. [21][22][23] Cathepsins are a group of papain/cysteine proteases with collagenolytic and elastinolytic activities involved in various aspects of extracellular matrix turnover and cathepsin B, in this context because it is involved in other degradative processes, is one of the most important members of this family. It has been reported that cathepsins are not only found in lysosomes but are also associated with digestion of the extracellular matrix. ...
Article
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Cathepsin B plays an important role in cell cycle, extracellular matrix changes and cutaneous tumorigenesis: whether it plays a role in photoaged skin remains unknown. This study aimed to investigate the role of cathepsin B in skin photoaging in vivo and in vitro. The expressions of cathepsin B were compared with immunohistochemical methods in solar exposed skin and solar protected skin of six healthy Chinese volunteers. The mRNA and protein expression of cathepsin B in ultraviolet light A (UVA) induced premature senescence fibroblasts in vitro were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting technique. Decreased expression of cathepsin B was observed in photoaged skin compared with that of the solar protected skin. In the UVA induced, premature senescence fibroblasts, a lower expression of cathepsin B was detected by Western blotting and a decreased synthesis of cathepsin B mRNA in the same cells was revealed by real-time RT-PCR. The results demonstrated a significant negative correlation between skin photoaging and cathepsin B in vitro and in vivo. We propose that cathepsin B, besides matrix metalloproteinases and antioxidant enzymes, is involved in the process of skin photoaging in that it contributes to extracellular matrix remodelling and is a dominant protease in cellular apoptosis and senescence.
Chapter
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Oxidative stress has been proposed to play a critical role in age-related cognitive impairment as well as in a number of age-related neurodegenerative disorders. As a result, numerous attempts have tried to use antioxidants to alleviate both types of debilitative conditions. While positive effects of a variety of antioxidant treatments have been found in experimental animals and models of human neurodegenerative disorders, carefully controlled human studies have in general found minimum if any effect of the majority of antioxidants tested. This chapter reviews some of these studies on both age-related cognitive impairment and age-related neurodegenerative conditions. It also discusses potential reasons for the failures of the small antioxidant molecules to alleviate both oxidative stress and functional consequences in humans. Finally, it proposes the hypothesis that small catalytic scavengers of reactive oxygen and reactive nitrogen species might provide significant protection against the deleterious effects of oxidative stress in humans.
Chapter
Numerous studies have been carried out in an attempt to elucidate the biochemical and molecular mechanisms of the aging process. The basic biochemical process underlying the aging process was first introduced in 1956 with the free radical theory of aging (1). This theory states that oxidative damage to DNA and other cellular components is the main driving force behind aging. More recent versions of this theory predict that mitochondria are a major source of reactive oxygen species (ROS) that cause oxidative damage. The idea that genetically damaged mitochondria accumulate with time and are causally responsible for the aging phenotype via a disturbed energy production and excessive ROS production is at the core of the so-called mitochondrial theory of aging (2). In 1989, Monnier proposed the Maillard theory of aging, stating that the fundamental aging process might be mediated by the Maillard reaction (the nonenzymatic reaction between reducing sugars and proteins, also known as the glycation process) (3). The free radical-glycation/Maillard reaction theory of aging brings those two views together. It suggests that free radicals (ROS) and reactive carbonyl species (RCS) from Maillard reactions may represent interactive elements of a more complex biochemical pathway. The age-related deterioration then results from the cumulative damage induced by ROS, by RCS, and by their interactions (4). Glycation of mitochondrial proteins results in the excessive formation of intracellular superoxide (5). It was recently shown that senescent human fibroblasts are characterized by a partial uncoupling of the respiratory chain, resulting in increased proton leakage and enhanced electron transport activity (6). Stöckl et al. (7) even suggested a cause-effect relationship between impaired mitochondrial coupling and premature senescence. Others have proposed a key role for high-level ROS-generating enzymes of the NOX family NADPH oxidases in causing age-related diseases (8,9). Oxidative damage to DNA has been found to be an important determinant of life span at least in lower organisms such as Drosophila melanogaster. Studies in higher organisms argue for a role of oxidative stress in age-related disease, especially cancer; however, the data remain inconclusive on whether oxidative stress determines life span (10). The general consensus appears to be that the aging process is multifactorial and that it results from an accumulation of damage with an underlying glycoxidative mechanism. Our interpretation of the glycoxidative model of aging is presented schematically in Figure 1.
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Because of increased leisure time, the growing popularity of staying outdoors, it has become more and more imperative to stady the molecular photobiological effects due to ultraviolet (UV) radiation on human skin information obtained from several studies is being used to constantly improve the quality of sunscreen preparations containing organic and inorganic filters. It also fostering the development of antioxidants and active agents that can be used in combination with or in addition to UV filters to provide better photoprotection for human skin. In this review, the examples are specified to illustrate the role and mechanism of highly specific and complex molecules obtained from natural sources; recognized as enzymes and examples are given to the development in skin care products: the use of topically applied DNA repair enzymes to prevent UVB radiation induced damage and the protective mechanism of superoxide dismutase and peroxidase to reduce UV-induced erythema, which can also be thought of as free radical scavenging ability.
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Cellulite is a serious cosmetic concern for most of the 90% of women affected by it. To assess the clinical efficacy of a complex integral anti-cellulite gel. This double-blind, randomized, placebo-controlled study involved 44 healthy women, aged 25-55 years. Subjects had a normal to slightly overweight body mass index and presented slight to moderate cellulite on their thighs, buttocks, and/or hips at baseline. Subjects were randomly assigned to either the treated or placebo group and accordingly applied the active product or placebo on their hips, stomach, buttocks, and thighs, twice daily for 3 months. Skin tonicity, orange-peel aspect, and stubborn cellulite were assessed at day 0, 28, 56, and 84. A self-evaluation questionnaire was completed by all volunteers. At the end of the study, an average of 81% of the subjects applying the active product presented improvement in their cellulite condition versus 32% for the placebo group (all descriptors and sites combined). At day 84, skin tonicity, orange-peel appearance, and stubborn cellulite were improved in a significant manner (P<0.05) over placebo, on all studied areas. Skin tonicity improved on average by +41% for buttocks, +35% for hips, and +31% for thighs. Orange peel appearance was reduced on average by -25% for buttocks, -22% for hips, and -22% for thighs. Stubborn cellulite was reduced on average by -19% for buttocks, -24% for hips, and -22% for thighs. Circumference measurements decreased in a significant manner (P<0.05) over placebo, for the abdomen (average value of -1.1 cm) and thighs (average value of -0.8 cm). The product was well tolerated and perceived by the volunteers themselves as better performing than placebo on all criteria. All results validate the efficacy of the present integral formulation to significantly reduce signs of cellulite and reshape the silhouette.
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In this work, we reported on the preparation and skin benefits of L-ascorbic acid 2-phosphate (VC-2-p)-loaded silk fibroin (SF) nanofibrous matrices for the first time. The matrices was fabricated using a facile eco-friendly electrospinning processing. With a post treatment of 75 v/v% ethanol vapor, the structure of the matrices transformed from unstable silk I form into water-stable silk II. In vitro release studies confirmed VC-2-p disassociated from SF nanofibrous matrices easily. Both neat and VC-2-p-loaded SF nanofibrous matrices were beneficial to mouse fibroblast L929 cells (L929 cells) adhering, spreading and proliferating against cover slips. Whereas compared with neat SF nanofibrous matrices, VC-2-p-loaded SF nanofibrous matrices significantly promoted the expression of collagen type I alpha 1 (Col1a1), as evidenced by real time PCR. Subsequently, the oxidative injury model further verified both matrices aided L929 cells through antioxidation to survive from tert-butyl hydroperoxide-induced oxidative stress (OS). Importantly, under severe OS, L929 cells on VC-2-p-loaded SF nanofibrous matrices maintained a higher mRNA level of Col1a1 as well as another two important functional genes, glutathione peroxidase 1 and catalase, than neat SF nanofibrous matrices. Our findings clearly indicated that the impressive skin benefits of SF nanofibrous matrices were further reinforced with the incorporation of VC-2-p, which implies the promising application of VC-2-p-loaded SF nanofibrous matrices in personal skin care and skin regeneration, including serving as wound dressings and anti-aging materials.
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As the mechanisms of skin aging become better understood, their complexity commands a different approach for antiaging benefits-i.e., integrating multiple complementary actives into a single formulation. In the present article, the authors describe a comprehensive formula designed to effectively address sixteen different mechanisms of skin aging.
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Salen Mn complexes, including EUK-134, EUK-189 and a newer cyclized analog EUK-207, are synthetic SOD/catalase mimetics that have beneficial effects in many models of oxidative stress. As oxidative stress is implicated in some forms of delayed radiation injury, we are investigating whether these compounds can mitigate injury to normal tissues caused by ionizing radiation. This review describes some of this research, focusing on several tissues of therapeutic interest, namely kidney, lung, skin, and oral mucosa. These studies have demonstrated suppression of delayed radiation injury in animals treated with EUK-189 and/or EUK-207. While an antioxidant mechanism of action is postulated, it is likely that the mechanisms of radiation mitigation by these compounds in vivo are complex and may differ in the various target tissues. Indicators of oxidative stress are increased in lung and skin radiation injury models, and suppressed by salen Mn complexes. The role of oxidative stress in the renal injury model is unclear, though EUK-207 does mitigate. In certain experimental models, salen Mn complexes have shown "mito-protective" properties, that is, attenuating mitochondrial injury. Consistent with this, EUK-134 suppresses effects of ionizing radiation on mitochondrial function in rat astrocyte cultures. In summary, salen Mn complexes could be useful to mitigate delayed radiation injury to normal tissues following radiation therapy, accidental exposure, or radiological terrorism. Optimization of their mode of delivery and other key pharmaceutical properties, and increasing understanding of their mechanism(s) of action as radiation mitigators, are key issues for future study.
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Cathepsins are involved in regulatory mechanisms in human skin, but their role in photoaged skin remains unknown. This study investigates the role of cathepsin B, D, K, and G in skin photoaging in vivo and in vitro. Cathepsin-induced changes in skin as a result of chronic UV irradiation were detected by immunohistochemistry methods. Protein cathepsin expressions in UVA-induced premature senescence in fibroblasts in vitro were detected by Western blot technique. Cathepsin mRNA expression in photoaged skin and fibroblasts was detected by real-time reverse transcription-polymerase chain reaction. Immunohistochemistry and Western blot show lower protein expression of cathepsin B, D, and K in photoaged skin and fibroblasts, while cathepsin G was higher. The mRNA expression of cathepsin B, D, and K of the photoaged skin in vivo decreased to 20 ± 0.5, 25 ± 1.6 and 22 ± 0.8%, while cathepsin G mRNA increased to 2.24 ± 0.09 times that of control. In photoaged fibroblasts, cathepsin B, D, and K mRNA was downregulated to 64 ± 2.9, 24 ± 2.1 and 9 ± 0.5% while cathepsin G mRNA was upregulated to 1.42 ± 0.06 times that of control fibroblasts. These experiments suggest that cathepsin B, D, K, and G may act as biomarkers in photoaged human skin.
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Human skin, exposed to a plethora of environmental insults that lead to free radicals and free radical damage, is equipped with an endogenous set of antioxidants, but these systems can become overwhelmed. Much study has focused on the therapeutic role of topical antioxidants but only a few investigate the utility of fruit extracts. Fruits are a rich source of diverse antioxidants and this article reviews their use for topical antioxidant protection. MEDLINE searches from 1966 to August 2008 and EMBASE searches from January 1974 through August 2008 were conducted for articles in English. In vitro and in vivo studies of fruit extracts used specifically with skin tissue or skin cells were selected for review. Fruits show diverse antioxidant activity in vitro and upon topical use in vivo. Studies have focused on antioxidant activity against reactive oxygen species (ROS) and ROS-induced signaling cascades. However, there has been little study regarding activity against reactive nitrogen or carbonyl species. Fruits may serve as a versatile source of antioxidants that can be harnessed for topical use. Several studies have shown efficacy in human in vivo studies and future studies will elucidate the versatility and clinical use of fruit extracts.
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We tested the theory that reactive oxygen species cause aging. We augmented the natural antioxidant systems of Caenorhabditis elegans with small synthetic superoxide dismutase/catalase mimetics. Treatment of wild-type worms increased their mean life-span by a mean of 44 percent, and treatment of prematurely aging worms resulted in normalization of their life-span (a 67 percent increase). It appears that oxidative stress is a major determinant of life-span and that it can be counteracted by pharmacological intervention.
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Many studies have demonstrated beneficial health effects of topical antioxidant application; however, the underlying mechanisms are not well understood. To better understand the protective mechanism of oxogenous anti-oxidants, it is important to clarify the physiological distribution, activity and regulation of antioxidants. Also, the generation of ROS by the resident and transient microbial flora and their interaction with cutaneous antioxidants appears to be of relevance for the redox properties of skin. Our studies have demonstrated that alpha-tocopherol is, relative to the respective levels in the epidermis, the major antioxidant in the human SC, that alpha-tocopherol depletion is a very early and sensitive biomarker of environmentally induced oxidation and that a physiological mechanism exists to transport alpha-tocopherol to the skin surface via sebaceous gland secretion. Furthermore, there is conclusive evidence that the introduction of carbonyl groups into human SC keratins is inducible by oxidants and that the levels of protein oxidation increase towards outer SC layers. The demonstration of specific redox gradients within the human SC may contribute to a better understanding of the complex biochemical processes of keratinization and desquamation. Taken together, the presented data suggest that, under conditions of environmentally challenged skin or during prooxidative dermatological treatment, topical and/or systemic application of antioxidants could support physiological mechanisms to maintain or restore a healthy skin barrier. Growing experimental evidence should lead to the development of more powerful pharmaceutical and cosmetic strategies involving antioxidant formulations to prevent UV-induced carcinogenesis and photoaging as well as to modulate desquamatory skin disorders.
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Manganese-salen complexes (Mn-Salen), including EUK-8 [manganese N,N'-bis(salicylidene)ethylenediamine chloride] and EUK-134 [manganese 3-methoxy N,N'-bis(salicylidene)ethylenediamine chloride], have been reported to possess combined superoxide dismutase (SOD) and catalase mimetic functions. Because of this SOD/catalase mimicry, EUK-8 and EUK-134 have been investigated as possible therapeutic agents in neurological disorders resulting from oxidative stress, including Alzheimer's disease, Parkinson's disease, stroke and multiple sclerosis. These actions have been explained by the ability of the Mn-Salen to remove deleterious superoxide (O(2)(-)) and H(2)O(2). However, in addition to oxidative stress, cells in models for neurodegenerative diseases may also be subjected to damage from reactive nitrogen oxides (nitrosative stress), resulting from elevated levels of NO and sister compounds, including peroxynitrite (ONOO(-)). We have been examining the interaction of EUK-8 and EUK-134 with NO and ONOO(-). We find that in the presence of a per-species (H(2)O(2), ONOO(-), peracetate and persulphate), the Mn-Salen complexes are oxidized to the corresponding oxo-species (oxoMn-Salen). OxoMn-Salens are potent oxidants, and we demonstrate that they can rapidly oxidize NO to NO(2) and also oxidize nitrite (NO(2)(-) to nitrate (NO(2)(-)). Thus these Mn-Salens have the potential to ameliorate cellular damage caused by both oxidative and nitrosative stresses, by the catalytic breakdown of O(2)(-), H(2)O(2), ONOO(-) and NO to benign species: O(2), H(2)O, NO(2)(-) and NO(3)(-).
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We tested the theory that reactive oxygen species cause aging. We augmented the natural antioxidant systems ofCaenorhabditis elegans with small synthetic superoxide dismutase/catalase mimetics. Treatment of wild-type worms increased their mean life-span by a mean of 44 percent, and treatment of prematurely aging worms resulted in normalization of their life-span (a 67 percent increase). It appears that oxidative stress is a major determinant of life-span and that it can be counteracted by pharmacological intervention.
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The physical, chemical, and biochemical factors that accelerate skin aging have been proposed to activate a self-maintained micro-inflammatory process, one of the expected end results of which is an imbalance in the turnover of macromolecules in the dermis. Surface peroxides are recognized as controllable factors of skin aging, and their accumulation is attributed to environmentally induced impairment of defense enzymes. Topical application of antioxidants decreases the rate at which skin elasticity and skin thickness are modified.
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Mitochondrial DNA (mtDNA) mutations and impaired respiratory function have been demonstrated in various tissues of aged individuals. We hypothesized that age-dependent increase of ROS and free radicals production in mitochondria is associated with the accumulation of large-scale mtDNA deletions. In this study, we first confirmed that the proportion of mtDNA with the 4977 bp deletion in human skin tissues increases with age. We then investigated the 8-hydroxy-2′-deoxyguanosine (8-OH-dG) content in skin tissues and lipid peroxides content of the skin fibroblasts from subjects of different ages. The results showed an age-dependent increase of 8-OH-dG level in the total DNA of skin tissues of the subjects above the age of 60 years. The specific content of malondialdehyde, an end product of lipid peroxidation, was also found to increase with age. On the other hand, we examined the enzyme activities of Cu,Zn-superoxide dismutase (Cu,Zn-SOD), Mn-superoxide dismutase (Mn-SOD), catalase, and glutathione peroxidase (GPx) in the skin fibroblasts. The activities of Cu,Zn-SOD, catalase and glutathione peroxidase were found to decrease with age. However, the activity of Mn-SOD was increased with age before 60 years but was decreased thereafter. Moreover, the activity ratios of Mn-SOD/catalase and Mn-SOD/GPx exhibited the same pattern of change with age. This indicates that free radical scavenging enzymes can effectively dispose of ROS and free radicals before 60 years of age. However, elevated oxidative stress caused by an imbalance between the production and removal of ROS and free radicals occurred in skin fibroblasts after 60 years of age. Taken together, we suggest that the functional decline of free radical scavenging enzymes and the elevation of oxidative stress may play an important role in eliciting oxidative damage and mutation of mtDNA during the human aging process.
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A comprehensive comparison of antioxidant defenses in the dermis and epidermis and their response to exposure to ultraviolet (UV) irradiation has not previously been attempted. In this study, enzymic and non-enzymic antioxidants in epidermis and dermis of hairless mice were compared. Enzyme activities are presented both as units/gram of skin and units/milligram of protein; arguments are presented for the superiority of skin wet weight as a reference base. Catalase, glutathione peroxidase, and glutathione reductase (units/gram of skin) were higher in epidermis than dermis by 49%, 86%, and 74%, respectively. Superoxide dismutase did not follow this pattern. Lipophilic antioxidants (alpha-tocopherol, ubiquinol 9, and ubiquinone 9) and hydrophilic antioxidants (ascorbic acid, dehydroascorbic acid, and glutathione) were 24-95% higher in epidermis than in dermis. In contrast, oxidized glutathione was 60% lower in epidermis than in dermis. Mice were irradiated with solar light to examine the response of these cutaneous layers to UV irradiation. After irradiation with 25 J/cm2 (UVA + UVB, from a solar simulator), 10 times the minimum erythemal dose, epidermal and dermal catalase and superoxide dismutase activities were greatly decreased. alpha-Tocopherol, ubiquinol 9, ubiquinone 9, ascorbic acid, dehydroascorbic acid, and reduced glutathione decreased in both epidermis and dermis by 26-93%. Oxidized glutathione showed a slight, non-significant increase. Because the reduction in total ascorbate and catalase was much more severe in epidermis than dermis, it can be concluded that UV light is more damaging to the antioxidant defenses in the epidermis than in the dermis.
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Lipid peroxide in human skin surface lipids was investigated. The correlation between the amount of lipid peroxide and the total amount of lipids in skin surface lipids was determined by statistical analysis. Furthermore, the correlation between lipid peroxide and squalene in skin surface lipids was also proved. These results suggest that the major source of lipid peroxide in skin surface is squalene, and that lipid peroxidation is enhanced by external factors such as ultraviolet light irradiation.
Article
This is the first study of antioxidants and oxidative-damage-related parameters in epidermis and dermis of the skin as a function of age. The four major antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase), hydrophilic and lipophilic antioxidants, and lipid hydroperoxides were assayed in both epidermis and dermis of young and old hairless mice. Catalase, superoxide dismutase, and glutathione reductase had similar activity levels in young and old animals. Only glutathione peroxidase from epidermis showed an activity decrease due to age. This decrease became apparent when enzyme activity was expressed per mg of total cellular protein. Hydrophilic and lipophilic antioxidants did not change as a function of age, nor did lipid hydroperoxide levels. Both the absolute level of oxidized glutathione and the ratio of oxidized to reduced glutathione were higher in dermis from old mice. These results suggest that skin aging is not accelerated in old age due to a general decrease in the antioxidant capacity of the tissue. The data are compatible, however, with the idea that continuous damage to skin tissue by free radicals occurs throughout an organism's lifetime because scavenging cannot be 100% efficient.
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The presence of ozone (O(3)) in photochemical smog is an important health concern. We hypothesized that the stratum corneum (SC), as the outermost skin layer and the permeability barrier of the skin, represents a sensitive target for O(3)-induced oxidative stress. To test this hypothesis, SKH-1 hairless mice were anesthetized and exposed for 2 h to O(3) by using two strategies: (i) single exposures to 0 (n = 12), 1 (n = 4), 5 (n = 4), and 10 (n = 4) ppm; and (ii) repeated daily exposures to 0 ppm (controls; n = 4) and 1 ppm (n = 4) for six consecutive days. New techniques based on the removal of SC by tape stripping were used to analyze the biologic effects of O(3) with respect to vitamin E depletion and lipid peroxidation. SC tissue was extracted from the tape and immediately analyzed by HPLC for vitamin E and malondialdehyde (MDA) concentrations. After in vivo exposure to increasing O(3) doses, vitamin E was depleted and MDA formation was increased, both in a dose-dependent manner. Remarkably, repeated low-level O(3) exposures resulted in cumulative oxidative effects in the SC: As compared with O(3) exposures of 0 ppm (alpha-tocopherol, 8.95 +/- 1.3 pmol per mg; gamma-tocopherol, 3.00 +/- 0.3 pmol per mg; MDA, 3.69 +/- 0.3 pmol per mg), vitamin E was depleted (alpha-tocopherol, 2.90 +/- 0.6 pmol per mg, p < 0.001; gamma-tocopherol, 0.5 +/- 0.1 pmol per mg, p < 0.001) and MDA levels were increased (4.5 +/- 0.2; p < 0.01). This report demonstrates the unique susceptibility of the SC to oxidative damage upon exposure to O(3).
Article
As the outermost barrier of the body, the stratum corneum (SC) is frequently and directly exposed to a pro-oxidative environment, including ultraviolet solar radiation (UVR). Therefore, we hypothesized that the SC is susceptible to UVR induced depletion of vitamin E, the major lipophilic antioxidant. To test this, we investigated (i) the susceptibility of SC tocopherols to solar simulated UVR in hairless mice, (ii) the baseline levels and distribution patterns of tocopherols in human SC, and (iii) the impact of a suberythemogenic dose of solar simulated UVR on human SC tocopherols. SC tocopherol levels were measured by high performance liquid chromotography analysis of SC extracts from tape strippings. In murine SC, overall tocopherol concentrations were determined, whereas in human SC, 10 consecutive layers were analyzed for each individual. The results on SC tocopherols demonstrated (i) their concentration dependent depletion by solar simulated UVR in hairless mice; (ii) a gradient distribution within untreated human SC, with the lowest levels at the surface (alpha-tocopherol 6.5 +/- 1.4 pmol per mg, and gamma-tocopherol 2.2 +/- 1.3 pmol per mg) and the highest levels in the deepest layers (alpha-tocopherol 76 +/- 12 pmol per mg, and gamma-tocopherol 7.9 +/- 3.7 pmol per mg, n = 10; p < 0.0001); and (iii) the depletion of tocopherols in human SC by a single suberythemogenic dose of solar simulated UVR (alpha-tocopherol by 45%, and gamma-tocopherol by 35% as compared with controls; n = 6; both p < 0.01). These results demonstrate that the SC is a remarkably susceptible site for UVR induced depletion of vitamin E.
Article
The stratum corneum has been recognized as the main cutaneous oxidation target of atmospheric ozone (O3), a major part of photochemical smog. This study reports the presence and distribution of vitamin C, glutathione, and uric acid in murine stratum corneum, and evaluates their susceptibility to acute environmental exposure to O3. Based on tape stripping and a modified extraction method with high performance liquid chromatography electrochemical analysis, we detected vitamin C (208.0 +/- 82.5 pmol per 10 consecutive pooled tapes), glutathione (283.7 +/-96.3), and uric acid (286.4 +/-47.1) in murine stratum corneum as compared with only 16.5 +/- 1.4 pmol alpha-tocopherol. Vitamin C, glutathione (both p < 00.001), and urate (p < 0.01) were found to exhibit a gradient with the lowest concentrations in the outer layers and a steep increase in the deeper layers. To investigate the effect of O3 exposure on hydrophilic antioxidants, we exposed SKH-1 hairless mice to O3 concentrations of 0, 0.8, 1, and 10 p.p.m., and stratum corneum was analyzed before and after exposure. Whereas mock exposure with 0 p.p. m. for 2 h had no significant effect, O3 doses of 1 p.p.m. for 2 h and above showed depletion of all three antioxidants. Vitamin C was decreased to 80% +/- 15% of its pretreatment content (p < 0.05), GSH to 41% +/- 24% (p < 0.01), and uric acid to 44% +/- 28% (p < 0.01). This report demonstrates the previously unrecognized role of hydrophilic antioxidants in the stratum corneum and provides further evidence that O3 induces oxidative stress in this outer skin layer.
Article
The comedogenicity of squalene peroxides was examined on the rabbit ear skin after topical application of squalene-monohydroperoxide (Sq-OOH), the initial product when squalene was irradiated with UV-A. Since comedogenic products from UV-irradiated squalene were extracted with methanol solution, we isolated Sq-OOH by reverse-phased HPLC with a methanol mobile phase solvent. The degree of comedogenic reaction induced by Sq-OOH was higher than that of well-known comedogenic cosmetic ingredients. Unlike two other mono-peroxides, tert-butyl hydroperoxide and cumene-mono-hydroperoxide, Sq-OOH induced comedo-formation in the rabbit ear skin. However, the comedogenicity of reduced Sq-OOH, squalene-hydroxide (Sq-OH) and squalene itself was lower than that of Sq-OOH. These results indicate that Sq-OOH is a potent comedogenic mono-hydroperoxide chemical to rabbit skin.
Article
Oxidative stress is defined as the result of an imbalance between prooxidants and antioxidants in living cells. This imbalance leads to molecular damage (peroxidation of lipids, metal-catalyzed carbonylation of proteins, and oxidative damage to DNA) as well as to modifications in cellular morphology (zeiosis, modification of chromatin structure) and tissue alterations. One way to illustrate the physiological consequences of oxidative stress imposed on human skin and the relevance of antioxidants is to analyze histology sections before and after an oxidative stress in the presence or absence of antioxidants. Morphological modifications of the ultraviolet-exposed epidermis are remarkable, particularly the loss of cell-to-cell contact and intercellular spongiosis. Protection afforded by the antioxidants against these morphological changes is nearly complete. However, histology methods are invasive and impractical for studies involving large cohorts of volunteers. Noninvasive techniques are therefore preferred for the analysis of the molecular consequences of the oxidative stresses induced by UVA, singlet oxygen, or ozone. For example, one might be interested in learning about the formation of oxidation products on the surface or in the different layers of the epidermis exposed to these environmental factors and its inhibition by antioxidants. This chapter describes some methodologies for investigating the effects of prooxidants and antioxidants on human epidermis.
Article
Skin is a tissue exposed most frequently to oxidative stress from the environment in daily life. Age-related changes of oxidative damage and antioxidant enzyme activity in the skin were examined in male Fischer 344 rats aged 6 to 30 months. The contents of phosphatidylcholine hydroperoxide (PCOOH) and thiobarbituric acid-reacting substances (TBARS) increased linearly with age. The content of cholesterol hydroperoxide increased until 24 months of age and then decreased. The content of 8-oxo-2'-deoxyguanosine (8-oxodG) increased gradually with age, and was significantly higher at 30 months of age than at 6 months of age. Superoxide dismutase activity tended to decrease with age. The activities of catalase and glutathione peroxidase showed no changes with age. We examined the effect of dietary restriction on the accumulation of oxidative damage in rat skin. The increase in PCOOH content in the skin of dietary-restricted rats was suppressed until 30 months of age. The TBARS and cholesterol hydroperoxide contents in the skin of dietary-restricted rats were significantly lower than in the skin of ad libitum-fed rats, while the 8-oxodG content was somewhat lower in the dietary-restricted rats than the ad libitum-fed rats. These results indicate that oxidative damage to the lipids and DNA in rat skin increases with age and that dietary restriction delays the accumulation of oxidative damage in skin.
Article
This is a comprehensive study of the changes in major antioxidant enzymes and antioxidant molecules during intrinsic aging and photoaging processes in the epidermis and dermis of human skin in vivo. We show that the activities of superoxide dismutase and glutathione peroxidase are not changed during these processes in human skin in vivo. Interestingly, the activity of catalase was significantly increased in the epidermis of photoaged (163%) and naturally aged (118%) skin (n = 9), but it was significantly lower in the dermis of photoaged (67% of the young skin level) and naturally aged (55%) skin compared with young (n = 7) skin. The activity of glutathione reductase was significantly higher (121%) in naturally aged epidermis. The concentration of alpha-tocopherol was significantly lower in the epidermis of photoaged (56% of young skin level) and aged (61%) skin, but this was not found to be the case in the dermis. Ascorbic acid levels were lower in both epidermis (69% and 61%) and dermis (63% and 70%) of photoaged and naturally aged skin, respectively. Gluta thione concentrations were also lower. Uric acid did not show any significant changes. Our results suggest that the components of the antioxidant defense system in human skin are probably regulated in a complex manner during the intrinsic aging and photoaging processes.
Article
Cigarette smoke, whether indirect or direct stream, is an environmental pollutant which presents an increasing health problem. In order to determine damage to human skin at the biochemical level, volar forearms were exposed to cigarette smoke for fifteen minutes and then assayed for the presence of stratum corneum lipid peroxides. A time-dependent increase was observed over a 24-hour post-exposure period. At 24 h, the average baseline level of lipid peroxides was 14.9 nmol/unit area of skin as compared to 32.0 nmol/unit area of skin for the smoke-exposed arms. In addition, when topical antioxidants were pre-applied to the skin and then exposed to cigarette smoke, an average decrease of 40.9% in lipid peroxide values was observed. These data demonstrate that peroxidation was induced in human skin by cigarette smoke and subsequently inhibited by the presence of antioxidants.
Article
There is increasing evidence for the generation of reactive oxygen species in skin upon ultraviolet exposure, but little is known about their pathophysiologic relevance in human skin in vivo. We hypothesized that chronic and acute photodamage is mediated by depleted antioxidant enzyme expression and increased oxidative protein modifications. Biopsies from patients with histologically confirmed solar elastosis, from non-ultraviolet-exposed sites of age-matched controls, and from young subjects were analyzed. To evaluate the influence of acute ultraviolet exposures, buttock skin of 12 healthy subjects was irradiated repetitively on 10 d with a solar simulator and compared intraindividually to non-ultraviolet-treated contralateral sites. The antioxidant enzymes catalase, copper-zinc superoxide dismutase, and manganese superoxide dismutase were investigated by immunohistochemistry. Protein carbonyls were analyzed by immunohistochemical and immunoblotting techniques in human skin and in cell models. Whereas overall expression of antioxidant enzymes was very high in the epidermis, low baseline levels were found in the dermis. In photoaged skin, a significant depletion of antioxidant enzyme expression was observed within the stratum corneum and in the epidermis. Importantly, an accumulation of oxidatively modified proteins was found specifically within the upper dermis of photoaged skin. Upon acute ultraviolet exposure of healthy subjects, depleted catalase expression and increased protein oxidation were detected. Exposures of keratinocytes and fibroblasts to ultraviolet B, ultraviolet A, and H2O2 led to dose-dependent protein oxidation and thus confirmed in vivo results. In conclusion, the correlation between photodamage and protein oxidation was demonstrated for the first time, which hence may be a relevant pathophysiologic factor in photoaging.
Article
Benzoyl peroxide (BPO) is a commonly used drug in the treatment of acne vulgaris, but it induces unwanted side effects related to stratum corneum (SC) function. Since it has been recently shown to oxidize SC antioxidants, it was hypothesized that antioxidant supplementation may mitigate the BPO-induced SC changes. To test this, 11 subjects were selected to be topically supplemented with alpha-tocotrienol (5% w/vol) for 7 d on defined regions of the upper back, while the contralateral region was used for vehicle-only controls. Starting on day 8, all test sites were also treated with BPO (10%) for 7 d; the alpha-tocotrienol supplementation was continued throughout the study. A single dose of BPO depleted 93.2% of the total vitamin E. While continuing the BPO exposure for 7 d further depleted vitamin E in both vehicle-only and alpha-tocotrienol-treated sites, significantly more vitamin E remained in the alpha-tocotrienol-treated areas. Seven BPO applications increased lipid peroxidation. Alpha-tocotrienol supplementation significantly mitigated the BPO-induced lipid peroxidation. The transepidermal water loss was increased 1.9-fold by seven BPO applications, while there was no difference between alpha-tocotrienol treatment and controls. The data suggest that alpha-tocotrienol supplementation counteracts the lipid peroxidation but not the barrier perturbation in the SC induced by 10% BPO.
Article
The stratum corneum, as the body's principal barrier to the environment, is continuously exposed to environmental sources of reactive oxygen species like ultraviolet light, ozone, and pollution. Reactive oxygen species are believed to be involved in cancer, aging, and inflammatory skin disorders. We have developed a method to measure catalase and superoxide dismutase activity on tape strippings from the human stratum corneum and demonstrated a gradient of antioxidant enzyme activity across the stratum corneum with decreasing levels towards the skin surface. Sun exposure resulted in a seasonal variation of the catalase activity in stratum corneum, with low activities in summer and higher activities in winter for the same person, whereas superoxide dismutase activity in stratum corneum did not seem to vary in those conditions. Exposure of human skin to broadband ultraviolet-A resulted in a dose-dependent deactivation of the catalase activity in stratum corneum within 24 h, whereas exposure to ultraviolet-B had no effect. Superoxide dismutase activity in stratum corneum was not affected by ultraviolet-A or ultraviolet-B irradiation within 24 h. After exposure to a dose of 15 J per cm2 broadband ultraviolet-A, full recovery of the catalase activity occurred in 3-4 wk at an age-dependent rate. We conclude that sun exposure results in a disturbed catalase to superoxide dismutase ratio in the stratum corneum. This may lead to an increased vulnerability to oxidative damage in stratum corneum barrier components. These results therefore stress the importance of providing efficient protection for this internal defense mechanism in sun-exposed areas of the skin.
Article
Although an understanding of the photobiology of the skin has been extensively advanced recently, the effect of ultraviolet (UV) radiation on sebaceous glands is not well known. In this study, we examined the direct effect of UV radiation on cultured sebocytes from hamsters in vitro experimental system. Moreover, we examined whether UV-induced peroxidation of skin surface lipids may affect barrier function of horney layer. We irradiated cultured sebocytes from hamsters, which have similar biological characteristics to the human sebocytes, with UV radiation. Moreover, transepidermal water loss (TEWL) was examined after topical application of cholesterol or triglyceride (TG) and UV exposures on the back of hamsters. The number of sebocytes were increased significantly (120-140%) after 4 days as compared with the non-irradiated controls. Lipid production in sebocytes was also increased on day 7 in an irradiation-dependent manner up to 4.1 times of the pre-irradiated level. When UVB was irradiated to TG- or cholesterol-applied skin at the minimum ear-swelling dose, TEWL increased twice or more as compared with UVB irradiation to unapplied sites. When in vitro-irradiated TG, in vitro-irradiated cholesterol, TG-peroxide (TG-OOH), and cholesterol-peroxide (CHO-OOH) were applied to the skin, TEWL increased significantly. These results suggest that UVB may directly activate the functions of the sebaceous gland in vivo to produce increased amounts of sebum, which may undergo peroxidation by UV light and damage the barrier functions of the skin.
Article
We have studied the effect of squalene monohydroperoxides (Sq-OOH), initial products of UV-peroxidated squalene, on the skin of hairless mice. Repeated topical application of 10 mM Sq-OOH to hairless mice for 15 weeks induced definite skin wrinkling. When image analysis was used to compare wrinkle formation induced by ultraviolet B (UVB) irradiation and Sq-OOH treatment, the degree of wrinkling in exposed skin was seen to be similar. However, the characteristics of wrinkles induced by either method differed markedly with regard to direction and distribution. Biochemical analysis revealed a significant decrease in collagen content per unit area and mass in Sq-OOH-treated skin, whereas no changes per unit area and decrease in collagen per unit mass were observed in UVB-irradiated skin. As for glycosaminoglycan (GAG) content per unit area, significant increases were observed in both Sq-OOH-treated skin and UVB-irradiated skin. These changes were not induced by organic hydroperoxides such as TERT-butylhydroperoxide or cumene hydroperoxide treatment. Histological observation revealed epidermal hyperplasia and dermal alterations such as collagen degradation and GAG increases in Sq-OOH-treated skin. Histological changes induced by Sq-OOH were not as pronounced as those induced by UVB irradiation. These results clearly suggest that the wrinkling and changes in dermal collagen content induced by Sq-OOH are qualitatively different to those induced by UVB exposure. This may provide a useful model for the study of skin aging, particularly with regard to collagen content.
Article
At the outermost surface of human skin, skin surface lipids are first-line targets of solar ultraviolet radiation. Therefore, we hypothesized that ultraviolet A and ultraviolet B irradiation induce photo-oxidation of skin surface lipids. To test this, sebum samples were collected from facial skin of 17 healthy volunteers, weighed, and immediately irradiated with either ultraviolet B or ultraviolet A. Squalene, the major sebum lipid, as well as photo-oxidation products were identified in sebum lipid extracts by high-performance liquid chromatography analysis. Upon ultraviolet A exposures squalene was depleted in a concentration-dependent manner, whereas an unidentified sebum lipid photo-oxidation product was detected. Using high-performance thin layer chromatography, high-performance liquid chromatography, atmospheric pressure chemical ionization mass spectrometry, and nuclear magnetic resonance, unidentified sebum lipid photo-oxidation product was identified as a mixture of squalene monohydroperoxide isomers. Squalene monohydroperoxide isomers purified from sebum were identical with squalene monohydroperoxide isomers synthesized by preparative photo-oxidation of squalene. Squalene monohydroperoxide isomers were formed even after small suberythematogenic doses of ultraviolet A (5 J per cm2). Whereas physiologic baseline levels of squalene monohydroperoxide isomers in human skin were only slightly above detection limits, squalene monohydroperoxide isomer levels were strongly increased by suberythematogenic doses of ultraviolet A both in vitro and in vivo. High-performance liquid chromatography results could be complemented by a straightforward thin layer chromatography method for rapid screening of lipid peroxide formation in human sebum/skin surface lipids. In conclusion, specific squalene monohydroperoxide isomers were identified as highly ultraviolet A sensitive skin surface lipid breakdown products that may serve as a marker for photo-oxidative stress in vitro and in vivo.
Article
The oxidative stress theory of aging has become increasingly accepted as playing a role in the aging process, based primarily on a substantial accumulation of circumstantial evidence. In recent years, the hypothesis that mitochondrially generated reactive oxygen species play a role in organismal aging has been directly tested in both invertebrate and mammalian model systems. Initial results imply that oxidative damage, specifically the level of superoxide, does play a role in limiting the lifespans of invertebrates such as Drosophila melanogaster and Caenorhabditis elegans. In mammalian model systems, the effect of oxidative stress on lifespan is less clear, but there is evidence that antioxidant treatment protects against age-related dysfunction, including cognitive decline.
Article
Photoaging is significantly different from chronological aging in both clinical and histological appearance. It has been suggested that oxidative stress, generated by ultraviolet radiation (UVR), leads to photoaging over a long period. The presence of 8-OHdG, and oxidatively modified proteins such as 4-hydroxy-2-nonenal-modified protein, 3-L-nitro-tyrosine and N(-epsilon) (carboxymethyl)lysine in UV-exposed skin specimens, supports this theory. The pathophysiology of photoaging of the skin caused by chronic inflammation after UVR is reviewed and discussed, with a focus on oxidative stress.
Article
Salen-manganese complexes exhibit powerful superoxide dismutase and catalase activity, with pharmacologic efficacy in several oxidative-stress-associated disease models. Ultraviolet (UV) B not only induces direct DNA damage, but also generates oxidative stress. EUK-134, a salen-manganese complex, might therefore confer a direct protection against UVB-induced oxidative stress and consequently alleviate UVB-damage-induced signal transduction. We investigated the effect of EUK-134 on the UVB-induced accumulation and stabilization of the p53 protein. p53 plays a central role in the UVB response, both as sensor of UVB damage and as a mediator of a protective response. Cells treated with EUK-134 before UVB irradiation showed a significantly lower accumulation of the p53 protein in a concentration-dependent fashion. Furthermore, EUK-134 severely reduced N-terminal phosphorylation of p53. The extracellular signal-regulated kinase ERK and the stress-activated kinases JNK and p38 have been implicated in the UVB-induced N-terminal phosphorylation and accumulation of p53. Pre-treatment with EUK-134 inhibited the UVB-induced activation of these mitogen-activated protein kinase (MAPK) pathways. We hypothesize that EUK-134, by direct protection of the membrane from UVB-induced oxidative damage, reduces oxidative stress induced MAPK signaling and consequently lowers the level of p53 induction. The protection conferred by EUK-134 resulted in a significant increase in cell survival following UVB irradiation.
Aging-and photoaging-dependent changes of enzymic and nonenzymic antioxidants in the epidermis and dermis of human skin in vivo Antioxidant enzyme activity in human stratum corneum shows seasonal variation with an age-dependent recovery
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Rhie, G.E., Shin, M.H., Seo, J.Y., et al. Aging-and photoaging-dependent changes of enzymic and nonenzymic antioxidants in the epidermis and dermis of human skin in vivo. J. Invest. Dermatol. 117(5), 1212–1217 (2001). 16. Hellemans, L., Corstjens, H., Neven, A., Declercq, L. and Maes, D. Antioxidant enzyme activity in human stratum corneum shows seasonal variation with an age-dependent recovery. J. Invest. Dermatol. 120, 434–439 (2003).
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Sharpe, A., Olloson, R., Stewart, V. and Clarl, J Oxi-dation of nitric oxide by oxomanganese-salen com-plexes: a new mechanism for cellular protection by superoxide dismutase/catalase mimetics. Biochem. J. 366, 97–107 (2002). (EUK-134) ª 2004 International Journal of Cosmetic Science, 26, 255–263 263 Treatment with the synthetic SOD/catalase mimetic EUK-134L. Declercq et al.
Treatment with the synthetic SOD/catalase mimetic EUK-134 L. Declercq et al. induced by repeated application of squalene monohydroperoxide to hairless mouse skin
Treatment with the synthetic SOD/catalase mimetic EUK-134 L. Declercq et al. induced by repeated application of squalene monohydroperoxide to hairless mouse skin. Skin Pharmacol. Appl. Skin Physiol. 16, 242–251 (2000).
Characteristics of skin wrinkling and dermal changes ª
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Chiba, K., Kawakami, K., Sone, T. and Onoue, M. Characteristics of skin wrinkling and dermal changes ª 2004 International Journal of Cosmetic Science, 26, 255–263