Impact of water exposure on skin barrier permeability and ultrastructure.

BACKGROUND: Skin occlusion caused by the use of diapers or sanitary napkins often results in irritant contact dermatitis. Furthermore, prolonged occlusion and exposure to body fluids are known to increase skin hydration and permeability, thus leading to irritant contact dermatitis. OBJECTIVE: To investigate the effects of water exposure on the skin and its barrier functions, in order to obtain more insights into the mechanisms of irritant contact dermatitis. METHODS: Water patches were applied to the volar forearm skin of 10 human subjects for 3 hours. Permeability of the stratum corneum (SC) was examined with methyl nicotinate (MN). Alterations in the hydration and ultrastructure of the SC were measured with Raman spectroscopy and multiphoton microscopy, respectively. RESULTS: Water profiles found with Raman spectroscopy showed notable increases in water content throughout the SC and skin surface. Multiphoton microscopy showed morphological changes in the intercellular space of the SC. Emerged pools seemed to contribute to increased MN absorption. CONCLUSION: Excessive skin hydration leading to changes in the SC ultrastructure might result in increased skin permeability to skin irritants and allergens.

Melanogenesis inhibitory activity of components from Salam leaf (Syzygium polyanthum) extract.

In order to identify a novel whitening agent, the methanol extract of S. polyanthum leaf was focused on by the screening test using nine Indonesian medicinal plants for the inhibition of melanogenesis and tyrosinase activity in B16 melanoma cells. Three novel compounds [(1) 1-(2,3,5-trihydroxy-4-methylphenyl)hexane-1-one, (2) 1-(2,3,5-trihydroxy methylphenyl)octane-1-one, and (3) (4E)-1-(2,3,5-trihydroxy-4-methylphenyl)decan-1-one and one known compound [(4) 1-(2,3,5-trihydroxy-4-methylphenyl)decan-1-one were isolated from the methanol extract. Our study demonstrated that S. polyanthum leaf methanol extract at 25-200 µg/mL decreased extracellular melanin formation ca. 20-80%, with high cell viability. Compounds 1-4 were found to be active in melanogenesis and tyrosinase inhibition. Compound 3 was the most active against tyrosinase activity (83.98 µM), particularly when L-tyrosine was the substrate. Compounds 1-4 significantly diminished extracellular melanin formation in B16 melanoma cells (> 80%), with high cell viability. Thus, our study suggested that compounds 1-4 isolated from the methanol extract of S. polyanthum leaf play important roles in decreasing extracellular melanogenesis and inhibiting tyrosinase.

Ethnic differences in stratum corneum functions between Chinese and Thai infants residing in Bangkok, Thailand.

BACKGROUND/OBJECTIVES: Ethnic and racial differences in infant skin have not been well characterized. The purpose of this study was to establish whether there are ethnic differences and similarities in the stratum corneum (SC) functions of Thai and Chinese infants. METHODS: Healthy infants 6 to 24 months of age (N = 60; 30 Thai, 30 Chinese) who resided in Bangkok, Thailand, were enrolled. Transepidermal water loss (TEWL) and SC hydration (capacitance) on the thigh, buttock, and upper arm were measured. Ceramide content was determined in the SC on the upper arm. RESULTS: SC hydration was not remarkably different between the two ethnicities at any site measured, but TEWL was significantly higher in Chinese infants than in Thai infants at all sites. Hydration of the SC was not significantly correlated with age in either ethnicity. TEWL had significant but weak correlations with age on the thigh and upper arm in Thai infants. Ceramide content was significantly higher in Chinese SC than in Thai SC. No relationship between ceramide content and TEWL or hydration was observed in either ethnicity. CONCLUSION: The significant differences in TEWL and ceramide contents between Chinese and Thai infant skin could prove useful in designing skin care and diapering products that are best suited for each ethnicity.

Properties of Skin in Chinese Infants: Developmental Changes in Ceramides and in Protein Secondary Structure of the Stratum Corneum.

The properties of infant skin regarding its structure and stratum corneum (SC) properties during development compared to adult skin have been reported only for a few races and body sites. The aim of this study was to understand the developmental changes of skin properties in Chinese infants, focusing on SC ceramides and protein secondary structure, which are important for skin barrier function. Three body sites with distinct characteristics (cheeks, inner upper arms, and buttocks) were assessed. Sixty pairs of Chinese infants and their mothers were measured for SC hydration, transepidermal water loss, ceramide levels, sebum with an ester bond, and protein secondary structure of superficial SC. Skin hydration decreased with age at all body sites. TEWL was similar between the 2-12- and 13-24-month-old groups but was higher than the adult group at the buttocks and inner upper arms and was equal to the adult group at the cheeks. These differences coincided with differences in protein secondary structure. Ceramide and sebum levels were lower in the infant groups. We conclude that both the SC functions and the components of infant skin are still developing and are not fully adapted as in adult skin at each body site examined.

Efficacy of the combined use of a mild foaming cleanser and moisturizer for the care of infant skin.

OBJECTIVE: Despite the application of skin care treatments, many infants have skin problems such as dryness and erythema. We proposed a new combination skin care for infants which consisted of a foaming cleanser with lower surfactant activity and moisturizers that contained pseudo-ceramide. SUBJECTS AND METHODS: A total of 50 infants (age: 3-24 months) with insignificant levels of dry skin were enrolled in this usage trial. The parents washed the infants with the test cleanser while bathing and then applied the moisturizer (lotion or cream) containing pseudo-ceramide. Prior to and following the 4-week usage period, visual evaluation of the skin condition was conducted by a dermatologist, in addition to instrumental analysis. RESULTS: Erythema and papule, accompanied by dryness, were commonly observed at week 0. However, by week 4, these symptoms significantly improved; the condition of none of the subjects deteriorated. The number of infants with lower cutaneous barrier function and higher skin pH decreased. The parents of the infants recognized improvements in the skin symptoms and were appreciative of the test materials. CONCLUSION: The combined usage of the foaming cleanser with lower surfactant activity and a moisturizer containing pseudo-ceramide may be effective in maintaining healthy infant skin and ameliorating the skin symptoms.

t-Flavanone Improves the Male Pattern of Hair Loss by Enhancing Hair-Anchoring Strength: A Randomized, Double-Blind, Placebo-Controlled Study.

INTRODUCTION: trans-3,4'-Dimethyl-3-hydroxyflavanone (t-flavanone) is a derivative of astilbin that actively stimulates hair growth. The aim of the present study was to identify the mechanisms of action of t-flavanone on hair growth. METHODS: A double-blind usage test was performed with healthy volunteers who had androgenic alopecia (AGA). The subjects were divided into three groups with equal average baldness. The members in each group applied a vasodilator-containing hair lotion supplemented with either 0, 0.1, or 0.3% (wt) t-flavanone twice a day for 30 weeks. The efficacy of t-flavanone was evaluated based on the parietal global and microscopic images. At week 30, the anchoring strength of hair was measured by the average peak force required for plucking out a single hair in a non-bald area using a digital force gauge. Desmoglein expression in the cultured human hair follicle was analyzed by Western blotting. RESULTS: After 30 weeks, t-flavanone significantly improved AGA and enhanced the hair-anchoring strength in a hair diameter-independent manner. Culture of human hair follicles in vitro with t-flavanone resulted in the upregulation of desmoglein protein expression. CONCLUSIONS: The results of our in vivo and in vitro studies demonstrated that t-flavanone enhanced the cell-cell adhesions in hair follicles; thus, reinforcement of hair rooting may be a mechanism by which t-flavanone promotes hair growth. FUNDING: Kao Corp.

The influence of incontinence on the characteristic properties of the skin in bedridden elderly subjects.

BACKGROUND: The mechanisms of skin breakdown induced by incontinence have been proposed from a variety of experimental studies. However, studies on the influence of skin properties caused by incontinence of bedridden subjects are very limited. OBJECTIVE: This work was conducted to reveal how incontinence influences skin properties by comparing bedridden incontinent elderly subjects with age-matched healthy continent elderly and middle-aged subjects. METHODS: Bedridden incontinent elderly subjects (n = 35, 83.5 ± 9.7 years, mean age ± SD), healthy continent elderly (n = 41, 75.9 ± 5.6 years), and middle-aged (n = 20, 41.3 ± 2.8 years) were recruited for this study. Skin surface pH, capacitance/hydration, transepidermal water loss, and bacteria on forearm and buttock skin were measured. RESULTS: Hydration and transepidermal water loss values between healthy elderly subjects and incontinent elderly subjects were significantly different on buttock skin. Significant differences between those two groups were also observed regarding pH and total bacteria levels on buttock skin. The forearm skin showed no significant difference in these parameters. No significant influence was observed between with and without urination at the measurement time except for the pH of buttock skin. No significant correlation was observed except between pH and bacteria levels on buttock skin of incontinent elderly subjects. CONCLUSION: In this study, we clarified the characteristic features of skin induced by incontinence. Our results indicate that these parameters are adequate not only to evaluate the characteristic skin features of bedridden incontinent subjects but also to develop new diapers to avoid the diaper dermatitis caused by incontinence.

Developmental alterations of physical properties and components of neonatal-infantile stratum corneum of upper thighs and diaper-covered buttocks during the 1st year of life.

BACKGROUND: Although physical properties of neonatal-infantile stratum corneum (SC) change drastically after birth, precise developmental alterations of specific sites have not been fully elucidated. OBJECTIVE: To determine the longitudinal alterations of neonatal-infantile SC functions and components of upper thighs and diaper-covered buttocks during the first year of life. The data were compared with those of adults. METHODS: Nineteen full-term neonates and their mothers were subjected to the measurements. Skin hydration, water sorption/retention capacity, TEWL were measured. Superficial SC analyses for NMF, ester binding sebum, and free fatty acids were performed by ATR-FTIR spectrometer. Total amount of ceramides (CERs) and CER subclasses were analyzed by NPLC-ESI-MS. RESULTS: SC hydration of neonatal thighs was lower than that of their mothers, which rapidly increased during the 1st month. Skin hydration of neonatal buttocks was similar to that of their mothers. This also rapidly increased during the 1st month. The neonatal TEWL was less than those of their mothers indicating more efficient barrier function at both sites, which significantly increased during the 1st year development. This was mostly correlated decreased in the ω-hydroxy fatty acid-esterified CERs. Superficial ester-binding sebum content of neonates was similar to that of their mothers, which significantly decreased during the measurement; the decrease was more marked on buttocks. Neither NMF nor FFA of the superficial SC showed significant alteration during the 1-year development. CONCLUSION: Our results indicate that physical functions and components of neonatal-infantile SC show considerable alterations between diaper-covered buttocks and upper thighs during the 1st year development.

Characterization of vulvar skin of healthy Thai women: influence of sites, age and menopause.

Although the physiological characteristics of vulvar skin have been characterized in Caucasians, little is known about the vulvar skin of Asian women. This study assessed the moisture content, transepidermal water loss (TEWL) and pH of vulvar skin of 99 healthy Asian women residing in Bangkok, aged 20-69 years, during their non-menstrual period, including 39 post-menopausal women. Skin pH was acidic at all sites, and the pH of the vulvar areas was significantly higher than the control sites (inner thigh, inner forearm). Skin moisture was slightly, but significantly, lower around the vulvar area and the thigh than around the forearm. TEWL was significantly higher in vulvar areas than control sites. Ageing and menopause did not cause notable alterations in most properties of vulvar skin. In conclusion, the vulvar skin of Asian women has similar properties to that of Caucasians.

Gender-dependent differences in degree of facial wrinkles.

BACKGROUND/PURPOSE: This study aimed to reveal gender-dependent differences in the degree of facial wrinkles. METHODS: Subjects comprised 173 Japanese men and women, divided into four groups according to age. Photographs were taken from nine facial regions and used to classify the intensity of wrinkles into five grades. In addition, replicas were taken from five facial sites and used to measure surface roughness. Data were compared between men and women within each age group. RESULTS: In all age groups, men showed increased forehead wrinkles compared with women. In contrast, no gender-dependent differences were found in upper eyelid wrinkles. Other facial wrinkles were greater in men than in women in all except the oldest group (age, 65-75 years), in which wrinkles in women were greater than or equal to those in men. CONCLUSION: Our results showed that gender-dependent differences exist in the degree of facial wrinkles. In general, men tend to have more severe wrinkles than women. This tendency disappeared or was reversed in some regions of the face and in individuals more than 60 years old.

A novel method to investigate the relationship between facial movements and wrinkle formation using particle image velocimetry.

BACKGROUND: The possible relationship between the direction of wrinkles and the movement of facial skin has not previously been reported. Therefore, we characterized that relationship using particle image velocimetry (PIV) analysis. METHOD: Twenty-one healthy Japanese women aged in their 20s (n = 7) or 50s (n = 14) were recruited for this study. Moving images of facial skin motions (closing the eyes tightly, raising the eyebrows) were captured using a single infrared camera under infrared ray irradiation of the skin. PIV analysis was then carried out using Flow-Vec32 software to determine the velocity and the direction of skin surface movements. RESULTS: All skin movements caused by those motions were finished within 0.20 s. During the motion of closing the eyes, skin at the eye periphery did not move in a superior-inferior direction, but did move toward the center of the eye (pupilla) with complex flows. There was no significant difference between either age group of subjects. During the motion of raising the eyebrows, the forehead skin moved upwards (direction to parietal) with relatively uniform flows. The velocity of movement at the top was lower than at the bottom, and that difference is likely to cause a deformation on the skin surface. A significant difference between the two age groups in the velocity was observed. CONCLUSION: The results show that the deformation of older skin on the forehead is greater than that in younger skin. The PIV analysis method is a useful tool to investigate some aspects of the relationship between facial skin movements and wrinkle formation.

The preliminary study of the relationship between facial movements and wrinkle formation.

BACKGROUND: As facial wrinkles develop particularly in areas of the skin that are subject to repeated facial movements, the degree of facial movements may be related to the degree of facial wrinkles, although no data have been reported. METHODS: Wrinkles were graded on the faces of Japanese female subjects when they made strong voluntary facial movements (eyes closed tightly, raised eyebrows, and frowns) and also when they were at rest using a set of photos (a photo scale) obtained from subjects with different degrees of wrinkles in the static and dynamic states. Scores obtained were compared between the dynamic and static states, and were analyzed in relation to age and to facial region. RESULTS: We found that the levels of wrinkles in both states showed a significant positive correlation with age. Further, the distribution of wrinkles in the dynamic state was found to be similar to those in the static states. Finally, the correlations between static and dynamic wrinkles in the same facial sites were higher than those in different facial sites. CONCLUSION: Facial movements cause wrinkling in both the dynamic and the static states and also that static wrinkles may work at the kinetic origins of dynamic wrinkles.

Loss of contraction force in dermal fibroblasts with aging due to decreases in myosin light chain phosphorylation enzymes.

Although there have been many reports about the relationship between force generation by skeletal muscles and aging, no study has investigated the relationship between contraction forces generated by non-muscle cells and aging. In this study, we examined that relationship using fibroblast populating collagen gels and a contraction force detecting system. Fibroblasts at passages 5 to 7 were used as the young group and those at passages 17 to 19 were used as the aged group. The contraction force induced by thrombin or lysophosphatidic acid significantly decreased with age. The expression of myosin light chain kinase (MLCK) and two types of Rho kinases (Rock-1 and Rock-2) decreased with age, but the expression of Rho A and myosin phosphatase (MPPase) did not change at all. The expression of myosin light chain 20k (MLC(20)) depended on the donor fibroblasts. Fibroblasts from young or aged hairless mice showed similar age-dependent results. Taken together, our data suggest that decreased expressions of MLCK and Rho kinase are critical for loss of force generation by fibroblasts with aging, which suggests new mechanisms of functional deficiencies due to aging.

Relationship between the echogenicity of subcutaneous tissue and the depth of eye corner wrinkles.

BACKGROUND/PURPOSE: A close relationship was found between the internal structure of subcutaneous tissue and wrinkle depth in our previous study of human forehead. The present study examined the relationship in the eye corner. METHODS: One hundred and seventy-three Japanese subjects were divided into four age groups (21-28 years, 35-41 years, 47-59 years and 65-75 years). The maximum wrinkle depth (Rmax) of an eye corner wrinkle was obtained. On an ultrasound image, which was captured by scanning perpendicular to the wrinkle, we set a 12.5-mm-wide region of interest (ROI) by aligning the deepest point of the wrinkle at its center and then obtained the ratio of the area exceeding an echogenicity threshold to the total area as the echogenicity. RESULTS: No correlation was found between the Rmax and echogenicity. The relationship was further analyzed by dividing the ROI into two: one above and the other below the deepest point of the wrinkle. A negative correlation was detected in the lower ROI of the oldest group. The difference in echogenicity between the upper and the lower ROIs of the oldest group showed a positive correlation with the Rmax. CONCLUSION: These results suggest that the subcutaneous tissue structure is related to wrinkle depth.

Relationship between the echogenicity of subcutaneous tissue and the depth of forehead wrinkles.

BACKGROUND/PURPOSE: Subcutaneous tissue is rarely studied in research on wrinkles. We used diagnostic ultrasonography to produce images of subcutaneous tissue of the forehead, one of the areas where age-related wrinkles form. We quantified the resulting echogenicity and investigated its relationship with wrinkle depth. METHODS: One hundred and seventy-three Japanese subjects were divided into four age groups (21-28 years, 35-41 years, 47-59 years, 65-75 years). Maximum wrinkle depth (Rmax) was measured in the forehead. On an ultrasound image, which was captured by scanning perpendicular to the deepest wrinkle, we set a 12.5-mm-wide region of interest by aligning the deepest point of the wrinkle at its center and then obtained the ratio of the area exceeding this threshold to the total area as the echogenicity. RESULTS: R max increased and the echogenicity decreased with age. A negative correlation was found in the oldest group but was not found in other groups, presumably due to individual differences in the echogenicity among younger subjects. CONCLUSION: This study suggests that the internal structure of subcutaneous tissue, as observed by ultrasonography, is related to wrinkle depth. The relationship between wrinkle depth and echogenicity of subcutaneous tissue is particularly pronounced in the elderly.

A new method for the visualization and quantification of internal skin elasticity by ultrasound imaging.

BACKGROUND/PURPOSE: Skin elasticity has been assessed previously only in the surface layer. We developed a new method that uses tissue strain imaging (TSI) technology, and the aim of this study was to test this new method to assess internal skin elasticity. METHODS: Using a pressure device with a 12 MHz ultrasound transducer, constant and linear compressions were applied to the cheek skin of 35 volunteers (aged: 20-60 years). The elasticity of each layer (dermis, subcutaneous and muscle) was measured and analyzed using the TSI application software incorporated into the Toshiba Aplio(™) XV ultrasound system. A skin tissue-equivalent phantom, which is a block of material with the acoustic velocity (1530 m/s) of human skin, was collaboratively developed by OST Inc. This phantom was placed between the skin and the transducer as a reference material. RESULTS: Skin elasticity was clearly visualized and quantified in each layer of the skin. Age-dependent decreases in elasticity were determined in all layers of the skin. Among the three internal skin layers, the highest elasticity was determined in the subcutaneous layer followed by the muscle layer. CONCLUSION: These findings support the validity and sensitivity of the TSI method to assess the elasticity of various layers of skin.

Enhancement of lipolytic responsiveness of adipocytes by novel plant extract in rat.

Subcutaneous adipocytes accumulate excess energy as triglycerides, but lipolytic response is less sensitive to catecholamines than visceral adipocytes. Obesity also induces catecholamine resistance of adipocytes. We have searched for crude drugs that could enhance the lipolytic response to noradrenalin. In this study, the lipolysis-promoting activities and action mechanisms of a novel plant extract from Hemerocallis fulva (HE) were investigated in isolated adipocytes from rat subcutaneous fat. HE exhibited no lipolysis-promoting activity alone but markedly promoted lipolysis when combined with noradrenaline; however, this synergistic activity was accompanied by no increase of intracellular cAMP production. This activity of HE was also observed when combined with cAMP analogue and was further enhanced by phosphodiesterase inhibitor. PKA inhibitor could reduce these activities of HE. These results indicate that HE is a novel lipolysis-promoting material that can sensitize the lipolytic response of adipocytes to catecholamine and suggest that HE can amplify the intra-cellular signaling pathway related to PKA or modify the other mechanism-regulating lipase activity. This characteristic material could contribute to improvement of adipose mobility in obesity-related disorder or in subcutaneous adiposity and to suppression of body fat accumulation.

The effect of eye opening and closing on the result of facial wrinkle assessment.

BACKGROUND/PURPOSE: Since there is no standard protocol that specifies the opening or closing of eyelids in wrinkle assessment, the eyelid position of subjects at the time of assessment varies from study to study. This study aimed to reveal the effect of eye opening and closing on the result of wrinkle assessment. The study also attempted to analyze the age-, site-, and ethnicity-dependent variations in the effect. METHODS: Open- and closed-eyed photographs were obtained from 87 Japanese women of ages ranging from 21 to 73 years, and also from 80 American women comprising of Asians, Caucasians, Africans and Hispanics in their 30s. Their wrinkle intensities were scored separately at nine facial sites using a five-point photo scale. The obtained scores were compared between open- and closed-eyed photographs. The differences were then compared across age- and ethnic-groups. RESULTS: In Japanese subjects, a significant difference was found at the forehead wrinkle in all age groups, and also at the glabella, nasal root and eye corner in the middle and old age groups. In American subjects, significant differences were found at the forehead, nasal root, eye-corner, and upper and lower eyelids. The differences were more prominent in the Hispanic and Caucasian Americans than in the Asian and African Americans. CONCLUSION: These results suggest that the eyelid position should be considered as a variable in wrinkle assessment.