Skin characteristics following repeated exposure to simulated outdoor and indoor summer temperatures in South Korea and Southeast Asia.

BACKGROUND: Although changes in skin depend on the external environment, researchers have performed only a few studies on effect of the actual environment. Most studies have researched skin characterization based on changes in the humidity or temperature. AIM/OBJECTIVE: This study aimed to evaluate changes in the skin based on the difference in indoor and outdoor temperatures and humidity during summer in South Korea and Southeast Asia. METHODS: Twenty-two female participants aged 25-39 years were included. Skin hydration, sebum (cheek, forehead), colour, transparency and pores of the participants were measured after a 30-min exposure to high temperature and high humidity (HTHH) environment and a 30-min exposure to low temperature and low humidity (LTLH) environment. Subsequently, exposure to HTHH environment for 30 min +LTLH environment for 30 min was performed after a total of 1 h and repeated. RESULTS: Repeated exposure to HTHH and LTLH environments increased the skin's sebum content and haemoglobin index. Additionally, skin elasticity was significantly reduced, with patients in their 30 s showing greater changes than those in their 20 s. CONCLUSION: Repeated differences in temperature and humidity cause skin ageing, loosen skin vessels and reduce skin elasticity, thereby leading to skin ageing.

CONTEXTE: Bien que les changements cutanés dépendent de l'environnement extérieur, les chercheurs n'ont réalisé que quelques études sur l'effet réel de cet environnement. La plupart des études ont examiné les caractéristiques de la peau en fonction des changements d'humidité ou de température. BUT/OBJECTIF: Cette étude visait à évaluer les changements de la peau en fonction de la différence de température et d'humidité à l'intérieur et à l'extérieur pendant l'été en Corée du Sud et en Asie du Sud-Est. MÉTHODES: Vingt-deux femmes âgées de 25 à 39 ans ont participé. L'hydratation de la peau, le sébum (joues, front), la couleur, la transparence et les pores des participants ont été mesurés après une exposition de 30 min à une température élevée et à un environnement à forte humidité (« high temperature and high humidity ¼, HTHH) et une exposition de 30 min à une température faible et à un environnement à faible humidité (« low temperature and low humidity ¼, LTLH). Par la suite, l'exposition à l'environnement HTHH pendant 30 min + environnement LTLH pendant 30 min a été effectuée après une durée de 1 h, puis répétée. RÉSULTATS: L'exposition répétée aux environnements HTHH et LTLH a augmenté la teneur en sébum et l'indice d'hémoglobine de la peau. En outre, l'élasticité de la peau était significativement réduite, les patientes ayant dépassé la trentaine montrant des changements plus importants que celles dans la vingtaine. CONCLUSION: Les variations répétées de température et d'humidité provoquent le relâchement des vaisseaux cutanés et réduisent l'élasticité de la peau, aboutissant ainsi au vieillissement de la peau.

Enhanced Transdermal Delivery by Combined Application of Dissolving Microneedle Patch on Serum-Treated Skin.

Dissolving microneedle (DMN), a transdermal drug delivery system in which drugs are encapsulated in a biodegradable polymeric microstructure, is designed to dissolve after skin penetration and release the encapsulated drugs into the body. However, because of limited loading capacity of drugs within microsized structures, only a small dosage can be delivered, which is often insufficient for patients. We propose a novel DMN application that combines topical and DMN application simultaneously to improve skin permeation efficiency. Drugs in pretreated topical formulation and encapsulated drugs in DMN patch are delivered into the skin through microchannels created by DMN application, thus greatly increasing the delivered dose. We used 4-n-butylresorcinol to treat human hyperpigmentation and found that sequential application of serum formulation and DMNs was successful. In skin distribution experiments using Alexa Fluor 488 and 568 dyes as model drugs, we confirmed that the pretreated serum formulation was delivered into the skin through microchannels created by the DMNs. In vitro skin permeation and retention experiments confirmed that this novel combined application delivered more 4-n-butylresorcinol into the skin than traditional DMN-only and serum-only applications. Moreover, this combined application showed a higher efficacy in reducing patients' melanin index and hyperpigmented regions compared with the serum-only application. As combined application of DMNs on serum-treated skin can overcome both dose limitations and safety concerns, this novel approach can advance developments in transdermal drug delivery.

A validation study to find highly correlated parameters with visual assessment for clinical evaluation of cosmetic anti-cellulite products.

BACKGROUND/PURPOSE: There has been growing interest in cellulite on parts of the body; however, no objective assessment has been specifically established. This study aims to demonstrate an optimized method by comparing the existing assessments of cellulite. METHODS: In Test 1, for subjects of 20 healthy females who have cellulite, we measured volume and roughness of cellulite using fringe projection method, roughness using replica method, dermo-subcutaneous interface length and subcutaneous thickness using ultrasonography and skin temperature using infrared ray, elasticity and blood flow. In Test 2, we applied an anti-cellulite cosmetic to 28 subjects for 6 weeks and observed if they have any changes. RESULTS: In Test 1, the effective parameter that is the most correlated with visual assessment was volume of skin measured using fringe projection method (r = 0.780). Dermo-subcutaneous interface length (r = 0.355) and subcutaneous thickness (r = 0.502) measured using ultrasonography followed in order. In Test 2, after applying a tested product, the correlation coefficient of volume of skin, of dermo-subcutaneous interface length and of subcutaneous thickness are 0.409 (P = 0.000), 0.275 (P = 0.016) and 0.311 (P = 0.012) respectively. CONCLUSION: We conclude that visual assessment, volume of skin (cavities), dermo-subcutaneous interface length and subcutaneous thickness are optimized methods for assessing an effect of cosmetics on cellulite.

Skin Color Analysis of Various Body Parts (Forearm, Upper Arm, Elbow, Knee, and Shin) and Changes with Age in 53 Korean Women, Considering Intrinsic and Extrinsic Factors.

Background/Objectives: Skin color is innately determined by race and other genetic factors, and it also undergoes acquired changes due to various intrinsic and extrinsic factors. Previous studies on skin color have mainly focused on the face, and research has recently expanded to other body parts. However, there is limited information about the age-dependent changes in the skin color of these body parts. The purpose of this study is to analyze the differences in skin color between various body parts and the changes in skin color of each body part with age. Methods: This study examined the skin color of 53 Korean women subjects evenly distributed in age from the 20s to 60s on several body parts: forearm, upper arm, elbow (extended or folded), knee (extended or folded), thigh, and shin. The lightness (L*), redness (a*), and yellowness (b*) were measured using a spectrophotometer, and the individual typology angle (ITA°) was calculated from the L* and b* values. The melanin index and erythema index were measured using the mexameter. Results: The results showed that the elbow skin had the lowest L* and ITA° values and the highest a* and b* values among the examined body parts, followed by the knee. The melanin index and erythema index were also high in the skin of these body parts. In the analysis of age-dependent changes in the skin color of various body parts, the forearm skin exhibited the most notable decrease in the L* and ITA° values and increases in the a* and b* values, followed by upper-arm skin. The melanin and erythema indices in the forearm also increased as the subjects aged, whereas those in the elbow and knee rather decreased with age. Conclusions: This study suggests that differences in intrinsic and extrinsic skin aging in various body parts may be expressed as different changes in skin color and raises the need for cosmetic and dermatological research to identify the physiological significance of these changes.

Combinatorial application of dissolving microneedle patch and cream for improvement of skin wrinkles, dermal density, elasticity, and hydration.

BACKGROUND: Dissolving microneedles (DMNs), microscale needles with a biodegradable polymer matrix, have been widely investigated for transdermal drug delivery. However, the restricted drug loading space of DMNs limited the delivery of the desired quantity of active compounds. In this study, we developed novel combinatorial therapies involving sequential application of adenosine-loaded DMN (Ad-DMN) patches and a topical adenosine-loaded cream (Ad-cream). The application of DMNs created skin channels, which delivered encapsulated drugs from both the DMNs and cream. The use of combinatorial therapies can maximize drug delivery. METHODS: To compare the efficacy of combinatorial therapies and Ad-cream application, a double-blind clinical test was conducted over 10 weeks on 21 females with wrinkles around their eyes, and the skin parameters such as wrinkles, dermal density, elasticity, and hydration were analyzed. The skin irritation test was assessed by expert interviewers to elucidate undesirable side effects. RESULTS: The combinatorial therapies showed statistically significant efficacy for the improvement of average depth of wrinkles, dermal density, elasticity, and hydration after an 8-week application (P < 0.001). Adverse effects on the skin were not observed in any subject during the test period. CONCLUSION: The efficacy and safety results showed that the combinatorial therapies were a safe and outstanding innovation for the optimization of transdermal therapy.

Two-phase delivery using a horse oil and adenosine-loaded dissolving microneedle patch for skin barrier restoration, moisturization, and wrinkle improvement.

BACKGROUND: Dissolving microneedles (DMNs) have been used for skin restoration and wrinkle improvement. Although lipophilic compounds, for example, natural oils or ceramides, enrich the skin barrier, their delivery via DMNs is challenging because of DMN fabrication difficulties. OBJECTIVES: In the present study, we combined a topical formulation and a DMN patch to perform two-phase delivery comprising a lipophilic formulation and hydrophilic compound-loaded DMNs to improve skin barrier status and the efficacy of drug delivery. METHODS: Horse oil-spread and adenosine-loaded DMN arrays were developed in a single patch (HOS-Ad-DMN patch). In vitro analysis was conducted to confirm the successful delivery of the compositions. Clinical assessments were conducted on the lateral canthus of 20 women to compare the efficacy of HOS-Ad-DMN patches with that of adenosine-loaded DMN patches (Ad-DMN patches). RESULTS: Adenosine was delivered via the DMNs after skin penetration and horse oil was delivered successfully into the skin through the microchannels created by the Ad-DMNs. Compared with Ad-DMN patches, HOS-Ad-DMN patches significantly improved skin elasticity, hydration, dermal density, and wrinkles. No adverse events were observed. CONCLUSION: HOS-Ad-DMN patches are a safe and efficient system for skin restoration and wrinkle improvement.

A study of the human skin-whitening effects of resveratryl triacetate.

Resveratrol has a variety of bioactivities that include its anti-melanogenic effects, but its use in cosmetics has been challenging partly because of its chemical instability. Resveratryl triacetate (RTA) is a prodrug that can enhance stability. The purpose of this study was to examine the skin safety and whitening effects of RTA in human subjects. The primary skin irritation potentials of RTA and resveratrol were tested at 0.1 and 0.5 % on human subjects. Resveratrol at a concentration of 0.5 % induced weak skin irritation, whereas RTA did not induce any skin responses. The skin-whitening efficacy of a cosmetic formulation containing 0.4 % RTA was evaluated in two different test models. In the artificial tanning model, the test product and the control product were applied twice daily to the skin of the forearms of 22 human subjects after pigmentation induction by ultraviolet irradiation. Applying the test and the control products to the artificial tanning model for 8 weeks increased the individual topology angles (ITA°) by 17.06 and 13.81 %, respectively, a difference that was statistically significant (p < 0.05). In the hyperpigmentation model, the test product and the control product were applied twice daily to the faces of 21 human subjects. The averaged intensity of the hyperpigmented spots decreased by 2.67 % in the test group and 1.46 % in the control group, a difference that was statistically significant (p < 0.05). Therefore, RTA incorporated into cosmetic formulations can whiten human skin without inducing skin irritation.

Clinical Evidence of Effects of Lactobacillus plantarum HY7714 on Skin Aging: A Randomized, Double Blind, Placebo-Controlled Study.

The beneficial effects of probiotics are now widely reported, although there are only a few studies on their anti-aging effects. We have found that Lactobacillus plantarum HY7714 (HY7714) improves skin hydration and has anti-photoaging effects, and in the present study, we have further evaluated the anti-aging effect of HY7714 via a randomized, double blind, placebo-controlled clinical trial. The trial included 110 volunteers aged 41 and 59 years who have dry skin and wrinkles. Participants took 1 × 10(10) CFU/day of HY7714 (probiotic group) or a placebo (placebo group) for 12 weeks. Skin hydration, wrinkles, skin gloss, and skin elasticity were measured every 4 weeks during the study period. There were significant increases in the skin water content in the face (p < 0.01) and hands (p < 0.05) at week 12 in the probiotic group. Transepidermal water loss decreased significantly in both groups at weeks 4, 8, and 12 (p < 0.001 compared with baseline), and was suppressed to a greater extent in the face and forearm in the probiotic group at week 12. Volunteers in the probiotic group had a significant reduction in wrinkle depth at week 12, and skin gloss was also significantly improved by week 12. Finally, skin elasticity in the probiotic group improved by 13.17% (p < 0.05 vs. controls) after 4 weeks and by 21.73% (p < 0.01 vs. controls) after 12 weeks. These findings are preliminary confirmation of the anti-aging benefit to the skin of L. plantarum HY7714 as a nutricosmetic agent.