Pascal PORTES - Academia.edu (original) (raw)

Papers by Pascal PORTES

The present invention relates to a cosmetic composition comprising an extract of almond seeds, an... more The present invention relates to a cosmetic composition comprising an extract of almond seeds, an extract of cells of leaves and almond extract buds Almond and its use for preventing or treating skin aging and / or firming the skin and / or smoothing the skin surface. The present invention also relates to a non-therapeutic method of cosmetic treatment comprising applying to the skin a cosmetic composition comprising an extract of almond seeds, an extract of cells of leaves and almond extract buds almond and to a kit for the non-therapeutic cosmetic treatment of the skin. The present invention finds particular application in cosmetics and / or dermatology.

Journal of Investigative Dermatology, 2019

Journal of Investigative Dermatology, 2018

Journal of Investigative Dermatology, 2017

PLOS ONE

Corsican Helichrysum italicum essential oil (HIEO) is characterized by high concentrations of ner... more Corsican Helichrysum italicum essential oil (HIEO) is characterized by high concentrations of neryl acetate, and we previously demonstrated that Corsican HIEO increases the expression of genes that are part of the differentiation complex (involucrin, small proline rich proteins, late cornified envelope, S100 protein family). The biological activities of HIEO and neryl acetate (NA) were compared to identify how NA contributes to HIEO activity on human skin. NA, as a part component of HIEO, was tested on skin explant models for 24 hours and 5 days in comparison with HIEO. We analyzed the biological regulations in the skin explant by transcriptomic analysis, skin barrier protein immunofluorescence, lipid staining and ceramide analysis by liquid chromatography-mass spectrometry. Transcriptomic analysis revealed that 41.5% of HIEO-modulated genes were also regulated by NA and a selected panel of genes were confirmed by qquantitative reverse transcription PCR analysis. Those genes are inv...

Experimental Dermatology, 2015

Several excipients are commonly used to enhance the drug absorption through simple epithelia of t... more Several excipients are commonly used to enhance the drug absorption through simple epithelia of the digestive tract. They permeate the paracellular barrier constituted by tight junctions (TJs). We compared the effects of two excipients, sodium caprate (C10) and a self‐emulsifying excipient Labrasol composed of a mixture of caprylocaproyl polyoxyl‐8 glycerides, both applied to emerged reconstructed human epidermis either ‘systemically’, that is by addition to the culture medium, or topically. During the ‘systemic’ application, which produced cytoplasmic translocation of occludin and leakage of the biotin marker into the lower stratum corneum, the decrease in the trans‐epithelial electrical resistance (TEER) was less abrupt with Labrasol when compared with C10, even though both excipients produced comparable final effects over time. With topical Labrasol, a significant TEER decrease was obtained with 5 times the ‘systemic’ concentrations. Topical application of C10 also resulted in th...

Toxicology in Vitro, 2002

The Episkin 1 model took part in the prevalidation study on in vitro tests for acute skin irritat... more The Episkin 1 model took part in the prevalidation study on in vitro tests for acute skin irritation of chemicals, which was carried out during 1999 and 2000. This prevalidation study was coordinated and supported by the European Centre for the Validation of Alternative Methods (ECVAM). During Phase 1 and Phase 2 of this study, reproducibility and transferability of the method were verified. Unfortunately, the performance of the method in terms of predictive ability was considered insufficient, due to a low specificity. In order to improve the performance of the Episkin 1 method, the existing protocol was refined. This refinement consisted in reducing the exposure time of epidermis with chemicals. Sensitivity, specificity and accuracy of the new method were 70, 80 and 75%, respectively, thus meeting the acceptance criteria as defined by the Management Team. The Episkin 1 method is now ready to enter a validation study of in vitro tests for acute skin irritation.

Toxicology in Vitro, 2001

Photodermatology, Photoimmunology & Photomedicine, 2002

Background/purpose: Drug-induced phototoxicity is a non-immunological inflammatory skin reaction,... more Background/purpose: Drug-induced phototoxicity is a non-immunological inflammatory skin reaction, caused by concurrent topical or systemic exposure to a specific molecule and ultraviolet radiation. Most of phototoxic compounds absorb energy particularly from UVA light leading to activated derivatives, which can induce cellular damage. This type of adverse cutaneous response can be reproduced, in vitro, using human skin models. In this study, we investigated the ability of human reconstituted epidermis EpiskinA to assess skin phototoxicity of weak phototoxic compounds such as 6-methylcoumarin and ofloxacin, compared to a strong one, chlorpromazine, and two negative controls (sodium dodecyl sulphate (SDS), sulisobenzone). Methods: After 1 h incubation with five test concentrations of each chemical compound, epidermis was then exposed or not to UVA at a non-cytotoxic dose 96 (50 J/cm 2). 18 h after UVA exposure, cellular damage was evaluated measuring cytotoxicity by MTT conversion test; in addition, pro-inflammatory mediator IL-1a release was also investigated. Results: Topical pretreatment of EpiskinA, with weak phototoxic compounds induced, after UVA exposure, a dose-dependent decrease in cell viability, in concordance with an increasing IL-1a release. Moreover, compared to chlorpromazine, the lower IL-1a release observed with 6-methylcoumarin and ofloxacin could be linked to their weak phototoxic potential. Conclusion: Human reconstituted epidermis Epis-kinA can be useful to study in vitro the onset of cutaneous phototoxic reactions and particularly to identify weak phototoxic compounds.

Photodermatology, Photoimmunology & Photomedicine, 2004

Background/Purpose: As ferritin has been identified as an important factor in antioxidant defense... more Background/Purpose: As ferritin has been identified as an important factor in antioxidant defense in cultured human skin cells, we evaluated UVA‐induced lipid hydroperoxides (LPO) production and ferritin expression in reconstructed human epidermis in vitro.Results: Ferritin is regularly present in the basal layer of unirradiated epidermis both in the human skin in vivo and in the reconstructed human epidermis in vitro. Following acute UVA exposure, ferritin expression increased in basal epidermal cells in both models. Quantitative analysis showed that, in reconstructed human epidermis, LPO and ferritin levels increased linearly with the UVA dose. An iron chelator, OR10141, inhibited these inductions.Conclusion: These findings demonstrate that reconstructed human epidermis is a useful in vitro model to study UVA‐induced oxidative stress and protection afforded by iron chelators, antioxidants or UVA absorbers.

Free Radical Biology and Medicine, 2010

Oxidative stress resulting from photosensitized ROS production in skin is widely accepted as the ... more Oxidative stress resulting from photosensitized ROS production in skin is widely accepted as the main contributor to the deleterious effects of UVA exposure. Among the mechanisms known to be involved in UVA-induced oxidative damage, iron plays a central role. UVA radiation of skin cells induces an immediate release of iron, which can then act as a catalyst for uncontrolled oxidation reactions of cell components. Such site-specific damage can scarcely be counteracted by classical antioxidants. In contrast, iron chelators potentially offer an effective way to protect skin against UVA insults. However, iron chelation is very difficult to achieve without disturbing iron homeostasis or inducing iron depletion. A novel compound was developed to avoid these potentially harmful side effects. Sideroxyl was designed to acquire its strong chelating capability only during oxidative stress according to an original process of intramolecular hydroxylation. Herein, we describe in vitro results demonstrating the protective efficiency of Sideroxyl against deleterious effects of UVA at the molecular, cellular, and tissular levels. First, the Sideroxyl diacid form protects a model protein against UVA-induced photosensitized carbonylation. Second, intracellular ROS are dose-dependently decreased in the presence of Sideroxyl in both human cultured fibroblasts and human keratinocytes. Third, Sideroxyl protects normal human fibroblasts against UVA-induced DNA damage as measured by the comet assay and MMP-1 production. Finally, Sideroxyl provides protection against UVA-induced alterations in human reconstructed skin. These results suggest that Sideroxyl may prevent UVA-induced damage in human skin as a complement to sunscreens, especially in the long-wavelength UVA range.

Experimental Dermatology, 2011

Several tight junction (TJ) proteins were detected in the living layers of adult human epidermis,... more Several tight junction (TJ) proteins were detected in the living layers of adult human epidermis, and TJ-like membrane ridges were observed at the top of the stratum granulosum (SG) in freeze-fracture studies. We applied standard and immunoelectron microscopy to look for TJ-derived structures in the stratum corneum (SC) of human adult epidermis and in cornified envelopes purified from the plantar SC. Besides confirming claudin-1 labelling in the proximity of SG desmosomes, we also observed immunolocalization near corneodesmosomes in the lower SC. In addition, TJ proteins were consistently detected in the purified cornified envelopes. Lateral but not horizontal walls of the corneocytes showed frequent points of molecular fusion between lipid envelopes. These structural associations were very frequently localized at the top of the lateral corneocyte membranes, thus sealing the extremities of lateral intercorneocyte spaces. We propose that TJ-like structures persist in the SC and contribute to the reinforcement of lateral contacts and to the formation of membrane interdigitations between corneocytes. Their presence could contribute to subdivision of the extracellular spaces of SC into consecutive individualized compartments. Intercellular lipids, enzymes and other (glyco)protein content could thus evolve in the keratinized epidermal layer at different paces, as preprogrammed in the underlying living cells and influenced by the environment, e.g. humidity. Such situation might explain differences in the degradation rates between the 'peripheral' and the 'non-peripheral' corneodesmosomes observed during physiological desquamation, as previously suggested by us and others.

Alternatives to Laboratory Animals, 2005

In view of the increasing need to identify non-animal tests able to predict acute skin irritation... more In view of the increasing need to identify non-animal tests able to predict acute skin irritation of chemicals, the European Centre for the Validation of Alternative Methods (ECVAM) focused on the evaluation of appropriate in vitro models. In vitro tests should be capable of discriminating between irritant (I) chemicals (EU risk: R38) and non-irritant (NI) chemicals (EU risk: “no classification”). Since major in vivo skin irritation assays rely on visual scoring, it is still a challenge to correlate in vivo clinical signs with in vitro biochemical measurements. Being particularly suited to test raw materials or chemicals with a wide variety of physical properties, in vitro skin models resembling in vivo human skin were involved in prevalidation processes. Among many other factors, cytotoxicity is known to trigger irritation processes, and can therefore be a first common event for irritants. A refined protocol (protocol15min–18hours) for the EPISKIN model had been proposed for inclus...

The present invention relates to a cosmetic composition comprising an extract of almond seeds, an... more The present invention relates to a cosmetic composition comprising an extract of almond seeds, an extract of cells of leaves and almond extract buds Almond and its use for preventing or treating skin aging and / or firming the skin and / or smoothing the skin surface. The present invention also relates to a non-therapeutic method of cosmetic treatment comprising applying to the skin a cosmetic composition comprising an extract of almond seeds, an extract of cells of leaves and almond extract buds almond and to a kit for the non-therapeutic cosmetic treatment of the skin. The present invention finds particular application in cosmetics and / or dermatology.

Journal of Investigative Dermatology, 2019

Journal of Investigative Dermatology, 2018

Journal of Investigative Dermatology, 2017

PLOS ONE

Corsican Helichrysum italicum essential oil (HIEO) is characterized by high concentrations of ner... more Corsican Helichrysum italicum essential oil (HIEO) is characterized by high concentrations of neryl acetate, and we previously demonstrated that Corsican HIEO increases the expression of genes that are part of the differentiation complex (involucrin, small proline rich proteins, late cornified envelope, S100 protein family). The biological activities of HIEO and neryl acetate (NA) were compared to identify how NA contributes to HIEO activity on human skin. NA, as a part component of HIEO, was tested on skin explant models for 24 hours and 5 days in comparison with HIEO. We analyzed the biological regulations in the skin explant by transcriptomic analysis, skin barrier protein immunofluorescence, lipid staining and ceramide analysis by liquid chromatography-mass spectrometry. Transcriptomic analysis revealed that 41.5% of HIEO-modulated genes were also regulated by NA and a selected panel of genes were confirmed by qquantitative reverse transcription PCR analysis. Those genes are inv...

Experimental Dermatology, 2015

Several excipients are commonly used to enhance the drug absorption through simple epithelia of t... more Several excipients are commonly used to enhance the drug absorption through simple epithelia of the digestive tract. They permeate the paracellular barrier constituted by tight junctions (TJs). We compared the effects of two excipients, sodium caprate (C10) and a self‐emulsifying excipient Labrasol composed of a mixture of caprylocaproyl polyoxyl‐8 glycerides, both applied to emerged reconstructed human epidermis either ‘systemically’, that is by addition to the culture medium, or topically. During the ‘systemic’ application, which produced cytoplasmic translocation of occludin and leakage of the biotin marker into the lower stratum corneum, the decrease in the trans‐epithelial electrical resistance (TEER) was less abrupt with Labrasol when compared with C10, even though both excipients produced comparable final effects over time. With topical Labrasol, a significant TEER decrease was obtained with 5 times the ‘systemic’ concentrations. Topical application of C10 also resulted in th...

Toxicology in Vitro, 2002

The Episkin 1 model took part in the prevalidation study on in vitro tests for acute skin irritat... more The Episkin 1 model took part in the prevalidation study on in vitro tests for acute skin irritation of chemicals, which was carried out during 1999 and 2000. This prevalidation study was coordinated and supported by the European Centre for the Validation of Alternative Methods (ECVAM). During Phase 1 and Phase 2 of this study, reproducibility and transferability of the method were verified. Unfortunately, the performance of the method in terms of predictive ability was considered insufficient, due to a low specificity. In order to improve the performance of the Episkin 1 method, the existing protocol was refined. This refinement consisted in reducing the exposure time of epidermis with chemicals. Sensitivity, specificity and accuracy of the new method were 70, 80 and 75%, respectively, thus meeting the acceptance criteria as defined by the Management Team. The Episkin 1 method is now ready to enter a validation study of in vitro tests for acute skin irritation.

Toxicology in Vitro, 2001

Photodermatology, Photoimmunology & Photomedicine, 2002

Background/purpose: Drug-induced phototoxicity is a non-immunological inflammatory skin reaction,... more Background/purpose: Drug-induced phototoxicity is a non-immunological inflammatory skin reaction, caused by concurrent topical or systemic exposure to a specific molecule and ultraviolet radiation. Most of phototoxic compounds absorb energy particularly from UVA light leading to activated derivatives, which can induce cellular damage. This type of adverse cutaneous response can be reproduced, in vitro, using human skin models. In this study, we investigated the ability of human reconstituted epidermis EpiskinA to assess skin phototoxicity of weak phototoxic compounds such as 6-methylcoumarin and ofloxacin, compared to a strong one, chlorpromazine, and two negative controls (sodium dodecyl sulphate (SDS), sulisobenzone). Methods: After 1 h incubation with five test concentrations of each chemical compound, epidermis was then exposed or not to UVA at a non-cytotoxic dose 96 (50 J/cm 2). 18 h after UVA exposure, cellular damage was evaluated measuring cytotoxicity by MTT conversion test; in addition, pro-inflammatory mediator IL-1a release was also investigated. Results: Topical pretreatment of EpiskinA, with weak phototoxic compounds induced, after UVA exposure, a dose-dependent decrease in cell viability, in concordance with an increasing IL-1a release. Moreover, compared to chlorpromazine, the lower IL-1a release observed with 6-methylcoumarin and ofloxacin could be linked to their weak phototoxic potential. Conclusion: Human reconstituted epidermis Epis-kinA can be useful to study in vitro the onset of cutaneous phototoxic reactions and particularly to identify weak phototoxic compounds.

Photodermatology, Photoimmunology & Photomedicine, 2004

Background/Purpose: As ferritin has been identified as an important factor in antioxidant defense... more Background/Purpose: As ferritin has been identified as an important factor in antioxidant defense in cultured human skin cells, we evaluated UVA‐induced lipid hydroperoxides (LPO) production and ferritin expression in reconstructed human epidermis in vitro.Results: Ferritin is regularly present in the basal layer of unirradiated epidermis both in the human skin in vivo and in the reconstructed human epidermis in vitro. Following acute UVA exposure, ferritin expression increased in basal epidermal cells in both models. Quantitative analysis showed that, in reconstructed human epidermis, LPO and ferritin levels increased linearly with the UVA dose. An iron chelator, OR10141, inhibited these inductions.Conclusion: These findings demonstrate that reconstructed human epidermis is a useful in vitro model to study UVA‐induced oxidative stress and protection afforded by iron chelators, antioxidants or UVA absorbers.

Free Radical Biology and Medicine, 2010

Oxidative stress resulting from photosensitized ROS production in skin is widely accepted as the ... more Oxidative stress resulting from photosensitized ROS production in skin is widely accepted as the main contributor to the deleterious effects of UVA exposure. Among the mechanisms known to be involved in UVA-induced oxidative damage, iron plays a central role. UVA radiation of skin cells induces an immediate release of iron, which can then act as a catalyst for uncontrolled oxidation reactions of cell components. Such site-specific damage can scarcely be counteracted by classical antioxidants. In contrast, iron chelators potentially offer an effective way to protect skin against UVA insults. However, iron chelation is very difficult to achieve without disturbing iron homeostasis or inducing iron depletion. A novel compound was developed to avoid these potentially harmful side effects. Sideroxyl was designed to acquire its strong chelating capability only during oxidative stress according to an original process of intramolecular hydroxylation. Herein, we describe in vitro results demonstrating the protective efficiency of Sideroxyl against deleterious effects of UVA at the molecular, cellular, and tissular levels. First, the Sideroxyl diacid form protects a model protein against UVA-induced photosensitized carbonylation. Second, intracellular ROS are dose-dependently decreased in the presence of Sideroxyl in both human cultured fibroblasts and human keratinocytes. Third, Sideroxyl protects normal human fibroblasts against UVA-induced DNA damage as measured by the comet assay and MMP-1 production. Finally, Sideroxyl provides protection against UVA-induced alterations in human reconstructed skin. These results suggest that Sideroxyl may prevent UVA-induced damage in human skin as a complement to sunscreens, especially in the long-wavelength UVA range.

Experimental Dermatology, 2011

Several tight junction (TJ) proteins were detected in the living layers of adult human epidermis,... more Several tight junction (TJ) proteins were detected in the living layers of adult human epidermis, and TJ-like membrane ridges were observed at the top of the stratum granulosum (SG) in freeze-fracture studies. We applied standard and immunoelectron microscopy to look for TJ-derived structures in the stratum corneum (SC) of human adult epidermis and in cornified envelopes purified from the plantar SC. Besides confirming claudin-1 labelling in the proximity of SG desmosomes, we also observed immunolocalization near corneodesmosomes in the lower SC. In addition, TJ proteins were consistently detected in the purified cornified envelopes. Lateral but not horizontal walls of the corneocytes showed frequent points of molecular fusion between lipid envelopes. These structural associations were very frequently localized at the top of the lateral corneocyte membranes, thus sealing the extremities of lateral intercorneocyte spaces. We propose that TJ-like structures persist in the SC and contribute to the reinforcement of lateral contacts and to the formation of membrane interdigitations between corneocytes. Their presence could contribute to subdivision of the extracellular spaces of SC into consecutive individualized compartments. Intercellular lipids, enzymes and other (glyco)protein content could thus evolve in the keratinized epidermal layer at different paces, as preprogrammed in the underlying living cells and influenced by the environment, e.g. humidity. Such situation might explain differences in the degradation rates between the 'peripheral' and the 'non-peripheral' corneodesmosomes observed during physiological desquamation, as previously suggested by us and others.

Alternatives to Laboratory Animals, 2005

In view of the increasing need to identify non-animal tests able to predict acute skin irritation... more In view of the increasing need to identify non-animal tests able to predict acute skin irritation of chemicals, the European Centre for the Validation of Alternative Methods (ECVAM) focused on the evaluation of appropriate in vitro models. In vitro tests should be capable of discriminating between irritant (I) chemicals (EU risk: R38) and non-irritant (NI) chemicals (EU risk: “no classification”). Since major in vivo skin irritation assays rely on visual scoring, it is still a challenge to correlate in vivo clinical signs with in vitro biochemical measurements. Being particularly suited to test raw materials or chemicals with a wide variety of physical properties, in vitro skin models resembling in vivo human skin were involved in prevalidation processes. Among many other factors, cytotoxicity is known to trigger irritation processes, and can therefore be a first common event for irritants. A refined protocol (protocol15min–18hours) for the EPISKIN model had been proposed for inclus...