Biological effects of air pollution on the function of human skin equivalents.

The World Health Organization reports that 99% of the global population are exposed to pollution levels higher than the recommended air quality guidelines. Pollution-induced changes in the skin have begun to surface; however, the effects require further investigation so that effective protective strategies can be developed. This study aimed to investigate some of the aging-associated effects caused by ozone and particulate matter (PM) on human skin equivalents. Full-thickness skin equivalents were exposed to 0.01 µg/µL PM, 0.05 µg/µL PM, 0.3 ppm ozone, or a combination of 0.01 µg/µL PM and 0.3 ppm ozone, before skin equivalents and culture medium were harvested for histological/immunohistochemical staining, gene and protein expression analysis using qPCR, Western blotting, and ELISA. Markers include MMP-1, MMP-3, COL1A1, collagen-I, 4-HNE, HMGCR, and PGE2. PM was observed to induce a decrease in epidermal thickness and an enhanced matrix building phenotype, with increases in COL1A1 and an increase in collagen-I protein expression. By contrast, ozone induced an increase in epidermal thickness and was found to induce a matrix-degrading phenotype, with decreases in collagen-I gene/protein expression and increases in MMP-1 and MMP-3 gene/protein expression. Ozone was also found to induce changes in lipid homeostasis and inflammation induction. Some synergistic damage was also observed when combining ozone and 0.01 µg/µL PM. The results presented in this study identify distinct pollutant-induced effects and show how pollutants may act synergistically to augment damage; given individuals are rarely only exposed to one pollutant type, exposure to multiple pollutant types should be considered to develop effective protective interventions.

Low-level red plus near infrared lights combination induces expressions of collagen and elastin in human skin in vitro.

OBJECTIVE: Light therapy has attracted medical interests as a safe, alternative treatment for photo-ageing and photo-damaged skin. Recent research suggested the therapeutic activity of red and infrared (IR) lights may be effective at much lower energy levels than those used clinically. This study was to evaluate the efficacy of low-level red plus near IR light emitting diode (LED) combination on collagen and elastin and ATP production. METHODS: Human dermal fibroblasts or skin tissues were irradiated daily by red (640 nm) plus near IR (830 nm) LED lights combination at 0.5 mW/cm2 for 10 minutes (0.3 J/cm2 ). qPCR, ELISAs or histology were used to determine the gene and protein expressions. Fluorescent measurement was used to assess crosslinks of collagen and elastic fibres. ATP production was evaluated by ATP assay. RESULTS: Treatment of human fibroblast cell cultures with low-level red plus near IR lights combination was found to significantly increase LOXL1, ELN and COL1A1 and COL3A1 gene expressions as well as the synthesis of the procollagen type I and elastin proteins. Treating human skin explants with low-level red plus near IR lights combination similarly induced significant increases in the same gene expressions, type III collagen and elastic fibre formation and crosslinks. ATP production was increased in human dermal fibroblasts after red plus near IR lights combination treatment. CONCLUSION: Low-level red plus near IR lights combination stimulated the production of collagen and elastin production associated with anti-ageing benefits. These findings suggest that low-level red plus near IR LED light combination may provide an effective treatment opportunity for people with photo-aged skin.

OBJECTIF: La luminothérapie a suscité des intérêts médicaux en tant que traitement alternatif sûr pour la photo-vieillissement et la peau endommagée. Des recherches récentes ont suggéré que L'activité thérapeutique des feux rouges et infrarouges (IR) pourrait être efficace à des niveaux d'énergie beaucoup plus faibles que ceux utilisés en clinique. Cette étude avait pour but d'évaluer l'efficacité de la combinaison de diodes électroluminescentes (DEL) rouges de faible intensité et de diodes électroluminescentes (IR) sur la production de collagène, d'élastine et d'ATP. MÉTHODES: Les fibroblastes dermiques humains ou les tissus cutanés ont été irradiés quotidiennement par une combinaison de feux rouges (640nm) et de feux à DEL proches de l'IR (830nm) à 0,5mW/cm2 pendant 10minutes (0,3J/cm2). qPCR, ELISA ou histologie ont été utilisés pour déterminer les expressions géniques et protéiques. Des mesures fluorescentes ont été utilisées pour évaluer les liens croisés du collagène et des fibres élastiques. La production d'ATP a été évaluée au moyen d'un essai ATP. RÉSULTATS: Le traitement de cultures de cellules de fibroblastes humaines avec une combinaison rouge de faible intensité et proche des lumières IR a permis d'augmenter significativement les expressions des gènes LOXL1, ELN et COL1A1 et COL3A1, ainsi que la synthèse des protéines de procollagène de type I et d'élastine. Le traitement des explants de peau humaine avec une combinaison rouge de bas niveau et proche des lumières IR a également induit des augmentations significatives dans les mêmes expressions géniques, la formation de collagène de type III et de fibres élastiques et les liaisons croisées. La production d'ATP a augmenté dans les fibroblastes dermiques humains après le traitement combiné rouge et proche des feux IR. CONCLUSION: L'association du rouge de bas niveau et des lumières infrarouges a stimulé la production de collagène et d'élastine associée aux bienfaits de l'antivieillissement. Ces résultats suggèrent que la combinaison de faible intensité de rouge plus proche de la lumière IR LED peut fournir une opportunité de traitement efficace pour les personnes ayant la peau photo-âgée.

Low-level red LED light inhibits hyperkeratinization and inflammation induced by unsaturated fatty acid in an in vitro model mimicking acne.

BACKGROUND AND OBJECTIVE: Acne vulgaris is a chronic inflammatory disease of the pilosebaceous units (PSU), associated with increased sebum production, abnormal follicular keratinization (hyperkeratinization), follicular overgrowth of Propionibacterium acnes (P. acnes), and increased inflammatory mediator release. Light therapy has attracted medical interests as a safe alternative treatment for acne. Both blue and red light therapies at high doses >10 J/cm2 have demonstrated marked effects on inflammatory acne lesions. However, few studies have investigated the effects of lower doses of light. The aim of this study is to investigate the biological effects of lower doses of red light at 0.2-1.2 J/cm2 for acne using an in vitro model previously developed to mimic the inflammation and hyperkeratinization observed clinically in acne. MATERIALS AND METHODS: Human epidermal equivalents were topically exposed to an unsaturated fatty acid, oleic acid (OA), followed by red light-emitting diode (LED) light treatments (light-plus-OA treatments). Endpoints evaluated included the proinflammatory cytokine IL-1α, epidermal barrier integrity, as measured by transepithelial electrical resistance (TEER), and stratum corneum (SC) thickness to monitor hyperkeratinization. RESULTS: OA-induced IL-1α release was significantly (P < 0.05) reduced following red LED light at 0.2, 0.5, and 1.2 J/cm2 , from 266 ± 11 pg/ml of no-light-plus-OA-treated (OA treatment without light) controls to 216 ± 9, 231 ± 8, and 212 ± 7 pg/ml, respectively. Histological examination showed that SC thickening following OA treatment was reduced from 43% of total epidermis for no-light-plus-OA treatment to 37% and 38% of total epidermis following 0.5 and 1.1 J/cm2 red light plus OA treatment, respectively (P < 0.05). Moreover, 1.1 J/cm2 red-light-plus-OA treatment improved OA-induced TEER changes from 29% of baseline for no-light-plus-OA treatment, to 36% of baseline. CONCLUSION: Low level red LED light therapy could provide beneficial effects of anti-inflammation, normalizing pilosebaceous hyperkeratinization, and improving barrier impairment in Acne vulgaris. Lasers Surg. Med. 50:158-165, 2018. © 2017 Wiley Periodicals, Inc.

In vitro modeling of unsaturated free fatty acid-mediated tissue impairments seen in acne lesions.

Acne vulgaris is a disease of pilosebaceous units with multifactorial pathogenesis, including hyperkeratinization, increased sebum secretion, and inflammation. Recently, it was suggested that acne subjects may have also impaired skin barrier. We hypothesized that excess unsaturated free fatty acids (UFFA) present in the sebum may cause barrier impairment associated with increased follicular stratum corneum (SC) thickening and inflammation seen in acne. Therefore, epidermal and sebaceous lipid profiles from acne and healthy subjects were analyzed and an in vitro epidermal tissue model was developed to validate this hypothesis. Significantly increased levels of free fatty acids (p < 0.05) were observed in skin lipids of human acne vs. healthy subjects. Exposure of human epidermal equivalents (HEEs) to the UFFA oleic acid (OA), also present in sebum, led to barrier impairment associated with increased SC lipid disorder, increased secretion of interleukin-1α (IL-1α), and excessive SC thickening. Furthermore, the expression of genes encoding for inflammatory cytokines and epidermal differentiation proteins was also increased both in acne lesions and in OA-treated HEEs. Taken together, these data are in agreement with the hypothesis that excess UFFAs in sebum of acne subjects may contribute to impaired skin barrier associated with the increased follicular SC thickness and inflammation seen in acne. Moreover, OA induces similar molecular and phenotypic changes in HEEs as those seen in acne lesions and suggests that an UFFA-treated epidermal tissue model can be used to study the UFFA-mediated pathways involved in the pathogenesis of inflammatory acne and for the development of appropriate therapies.

Topical stabilized retinol treatment induces the expression of HAS genes and HA production in human skin in vitro and in vivo.

Skin Aging manifests primarily with wrinkles, dyspigmentations, texture changes, and loss of elasticity. During the skin aging process, there is a loss of moisture and elasticity in skin resulting in loss of firmness finally leading to skin sagging. The key molecule involved in skin moisture is hyaluronic acid (HA), which has a significant water-binding capacity. HA levels in skin decline with age resulting in decrease in skin moisture, which may contribute to loss of firmness. Clinical trials have shown that topically applied ROL effectively reduces wrinkles and helps retain youthful appearance. In the current study, ROL was shown to induce HA production and stimulates the gene expression of all three forms of hyaluronic acid synthases (HAS) in normal human epidermal keratinocytes monolayer cultures. Moreover, in human skin equivalent tissues and in human skin explants, topical treatment of tissues with a stabilized-ROL formulation significantly induced the gene expression of HAS mRNA concomitant with an increased HA production. Finally, in a vehicle-controlled human clinical study, histochemical analysis confirmed increased HA accumulation in the epidermis in ROL-treated human skin as compared to vehicle. These results show that ROL increases skin expression of HA, a significant contributing factor responsible for wrinkle formation and skin moisture, which decrease during aging. Taken together with the activity to increase collagen, elastin, and cell proliferation, these studies establish that retinol provides multi-functional activity for photodamaged skin.

The helix-loop-helix transcription factor Id1 is highly expressed in psoriatic involved skin.

The helix-loop-helix transcription factor Id1 (inhibitor of differentiation/inhibitor of DNA binding) functions as an inhibitor of differentiation. We have examined Id1 gene expression in cultured keratinocytes in punch biopsies from psoriatic involved and uninvolved skin, and in skin specimens from normal individuals. Id1 mRNA expression was measured with an RNase protection assay and with Northern blot. Id1 immunoreactivity was determined in skin biopsies by immunofluorescence using a polyclonal antibody directed against the Id1 protein. In cultured keratinocytes, the expression of Id1 mRNA was strongest in small cells with high proliferative potential, whereas in large cells, which are terminally differentiated, the expression was low. Expression of the Id1 mRNA in psoriatic involved skin (n = 9) was significantly elevated compared to uninvolved skin from the same patient (n = 5) and to skin from normal controls (n = 9). Id1 immunoreactivity was intranuclear throughout all the layers in psoriatic involved epidermis, except in the stratum corneum, while no immunoreactivity was detected in uninvolved epidermis. In normal controls, cytoplasmatic Id1 immunoreactivity was detected in the basal layer in epidermis obtained from newborns, while no immunoreactivity was detected in epidermis obtained from the adults in the control group. We conclude that Id1 is expressed in cells with high proliferative potential, and is downregulated in cells that undergo terminal differentiation. Along with the overexpression of the Id1 gene in psoriatic involved skin, these observations suggest that Id1 is involved in the process of differentiation of keratinocytes seen in normal skin and that the Id1 pathway is activated in psoriasis.