Effects of ultraviolet rays and particulate matter on hair porosity in damaged hair.

BACKGROUND: With growing interest in hair health, researchers are exploring aspects beyond the surface qualities of hair, such as its porous inner structure. While previous studies have focused on the effects of treatments such as perming and hair dying on hair porosity, less emphasis has been paid to the effects of harmful environmental factors such as ultraviolet (UV) rays and particulate matter on the porous nature of hair. AIMS: The aim of this study was to bridge this gap by investigating how UV rays and particulate matter affect hair porosity in different ways. Our study could help elucidate how these external factors influence hair health and shed light on previously unknown aspects of hair porosity. METHODS: Hair tresses were bleached, cut into 1 cm-long sections, and stained with methylene blue. The sections were then irradiated with UV light or exposed to particulate matter. RESULTS: Bleached hair absorbed more methylene blue than normal hair. UV radiation-induced hair porosity occurred at 3 h after irradiation and increased with time. Particulate matter alone did not affect the porosity of the damaged hair; however, in combination with UV irradiation, it substantially increased hair porosity. CONCLUSION: Environmental challenges such as a depleted ozone layer and increasing pollution may increase hair porosity, which can be prevented by maintaining healthy hair.

Two newly developed indices evaluating facial skin aging.

BACKGROUND: Skin assessment methodologies have focused mainly on intuitive aging characteristics, including facial wrinkles and pigmented spots, and usually adopt pattern recognition algorithms. Recently, distinct methods of interpreting skin aging, such as the detection of facial landmarks and age prediction using machine learning techniques, have been conducted. MATERIALS AND METHODS: We defined two indices that represent the severity of facial aging. The first index was the ratio of the bizygomatic distance and bigonial distance. The second index was the ratio of the degrees of the near mandible. The indices extracted from two-dimensional frontal face images were intended to show the deformation of the facial skin downward with aging progress. To validate whether these proposed indicators can represent facial aging, we conducted correlation tests with age and facial skin characteristics and performed association tests between the indices and facial skin characteristics, adjusted for age. RESULTS: The indices showed strong correlations with age (r = 0.557 and 0.464, respectively) and facial skin characteristics. Although there were correlations between the indices and facial skin features, the associations between the indices and facial skin characteristics adjusted for age were weak or not significant. This suggests that the newly developed indices are appropriate for evaluating facial skin aging and distinct from typical measurements. CONCLUSION: We suggest two novel indices for evaluating facial aging based on frontal face images. The indices exhibited strong correlations with age and representative facial skin characteristics. The newly developed values can be differentiated indicators of facial aging compared with general skin features.

Identifying patterns behind the changes in skin pores using 3-dimensional measurements and K-means clustering.

BACKGROUND: Skin pores are structural features of the skin, which tend to change as the skin ages. Since previous studies measured pores two-dimensionally, precise measurements using three-dimensional imaging were needed to comprehensively understand skin pores. This study aimed to determine the patterns behind the changes in skin pores during one's lifetime and to identify new characteristics of the pores in aged. MATERIALS AND METHODS: Skin surface profiles were measured three-dimensionally from the cheeks of 101 Korean women from February to March 2020 to analyze the exact state of their pores. The researchers performed K-means clustering to classify the skin pores, and topographical features of pores were analyzed as well. Statistical analyses were performed to verify the differences in the skin pore characteristics among clusters and the correlation between clusters and ages. RESULTS: Skin pores were classified into five groups based on size, density, and elongation. The skin conditions of the cluster groups were well correlated with aging, despite excluding age as a factor in pore classification. Adjacent skin pores tend to connect in the elderly. CONCLUSION: Skin pores become larger and longer over time. Skin pores connect together in the elderly, which might be related to wrinkle formation. This phenomenon strongly suggests skin pores as a characteristic of aging skin and as a potential target for anti-aging treatment.

Relationship between lip skin biophysical and biochemical characteristics with corneocyte unevenness ratio as a new parameter to assess the severity of lip scaling.

OBJECTIVE: Lip skin dryness and chapping are major concerns related to lip skin care in many populations. The distinctive features of lip skin, such as the low water-holding capacity and weak skin barrier, are strongly associated with these problems; however, few studies have examined lip skin characteristics and the mechanisms underlying these issues. This study was conducted to identify the biophysical properties of dry lip skin and molecular targets affecting lip skin physiology. METHODS: Skin hydration, transepidermal water loss and lip skin scaling were evaluated in 40 female subjects. Skin scaling was assessed as a percentage area divided into five categories (G0, G1, G2, G3 and G4) according to the thickness level of tape-stripped corneocytes. The activities and amounts of proteases, cathepsin D and bleomycin hydrolase were measured as markers for the desquamation process and skin hydration, respectively. RESULTS: Skin hydration showed a significantly positive correlation with the percentage area of evenly thin corneocytes (G0) and negative correlations with the percentage areas of slightly thick to severely thick corneocytes (G1-G4). The corneocyte unevenness ratio (CUR) was calculated by dividing the sum of the G1, G2, G3 and G4 values with the G0 value. The CUR was significantly negatively correlated with skin hydration, suggesting that CUR is a new parameter representing the severity of lip scaling. Subjects with lower hydration and higher CUR had higher bleomycin hydrolase activity and lower cathepsin D activity, respectively, than subjects with higher hydration and lower CUR. CONCLUSION: Our study revealed a correlation between lip skin hydration and severity of lip scaling and verified the association of protease activity with the hydration and chapping state of lip skin. These observations provide a basis for further studies of the persistent problem of lip skin dryness and chapping.

OBJECTIF: La sécheresse et la gerçure de la peau des lèvres sont des préoccupations majeures liées aux soins de la peau des lèvres chez de nombreuses populations. Les caractéristiques distinctives de la peau des lèvres, telles que la faible capacité de rétention d'eau et la faible barrière cutanée, sont fortement associées à ces problèmes ; cependant, peu d'études ont examiné les caractéristiques de la peau des lèvres et les mécanismes sous-jacents à ces problèmes. Cette étude a été menée dans le but d'identifier les propriétés biophysiques de la peau sèche des lèvres et les cibles moléculaires affectant la physiologie de la peau des lèvres. MÉTHODES: L'hydratation cutanée, la perte d'eau transépidermique et la desquamation de la peau des lèvres ont été évaluées chez 40 sujets de sexe féminin. La desquamation cutanée a été évaluée en tant que pourcentage de surface, divisée en cinq catégories (G0, G1, G2, G3 et G4) en fonction du niveau d'épaisseur des cornocytes sur la bande adhésive. Les activités et quantités des protéases, de la cathepsine D et de la bléomycine hydrolase ont été mesurées comme marqueurs du processus de desquamation et de l'hydratation cutanée, respectivement. RÉSULTATS: L'hydratation cutanée a montré une corrélation significativement positive avec le pourcentage de surface avec cornocytes uniformément minces (G0), et des corrélations négatives avec les pourcentages de surface avec cornocytes légèrement épais à très épais (G1-G4). Le rapport d'irrégularité des cornocytes (Corneocyte Unevenness Ratio, CUR) a été calculé en divisant la somme des valeurs de G1, G2, G3 et G4 par la valeur de G0. Le CUR était significativement corrélé négativement avec l'hydratation de la peau, ce qui suggère que le CUR est un nouveau paramètre représentant la gravité de la desquamation des lèvres. Les sujets avec une hydratation plus faible et un CUR plus élevé présentaient une activité de la bléomycine hydrolase plus élevée et une activité de la cathepsine D plus faible, respectivement, par rapport aux sujets avec une hydratation plus élevée et un CUR plus faible. CONCLUSION: Notre étude a révélé une corrélation entre l'hydratation de la peau des lèvres et la gravité de la desquamation des lèvres, et a vérifié l'association de l'activité de la protéase avec l'état d'hydratation et de gerçure de la peau des lèvres. Ces observations fournissent une base pour d'autres études sur le problème persistant de la sécheresse et de la gerçure de la peau des lèvres.