A Soluble Fiber Diet Increases Bacteroides fragilis Group Abundance and Immunoglobulin A Production in the Gut.

Immunoglobulin A (IgA) is essential for defense of the intestinal mucosa against harmful pathogens. Previous studies have shown that Bacteroidetes, the major phylum of gut microbiota together with Firmicutes, impact IgA production. However, the relative abundances of species of Bacteroidetes responsible for IgA production were not well understood. In the present study, we identified some specific Bacteroidetes species that were associated with gut IgA induction by hsp60-based profiling of species distribution among Bacteroidetes The levels of IgA and the expression of the gene encoding activation-induced cytidine deaminase (AID) in the large intestine lamina propria, which is crucial for class switch recombination from IgM to IgA, were increased in soluble high-fiber diet (sHFD)-fed mice. We found that Bacteroides acidifaciens was the most abundant Bacteroidetes species in both sHFD- and normal diet-fed mice. In addition, the gut IgA levels were associated with the relative abundance of Bacteroides fragilis group species such as Bacteroides faecis, Bacteroides caccae, and Bacteroides acidifaciens Conversely, the ratio of B. acidifaciens to other Bacteroidetes species was reduced in insoluble high-fiber diet fed- and no-fiber diet-fed mice. To investigate whether B. acidifaciens increases IgA production, we generated B. acidifaciens monoassociated mice and found increased gut IgA production and AID expression. Collectively, soluble dietary fiber increases the ratio of gut Bacteroides fragilis group, such as B. acidifaciens, and IgA production. This might improve gut immune function, thereby protecting against bowel pathogens and reducing the incidence of inflammatory bowel diseases.IMPORTANCE Immunoglobulin A (IgA) is essential for defense of the intestinal mucosa against harmful pathogens. Gut microbiota impact IgA production, but the specific species responsible for IgA production remain largely elusive. Previous studies have shown that IgA and Bacteroidetes, the major phyla of gut microbiota, were increased in soluble high-fiber diet-fed mice. We show here that the levels of IgA in the gut and the expression of activation-induced cytidine deaminase (AID) in the large intestine lamina propria, which is crucial for class switch recombination from IgM to IgA, were correlated with the abundance of Bacteroides fragilis group species such as Bacteroides faecis, Bacteroides caccae, and Bacteroides acidifaciensB. acidifaciens monoassociated mice increased gut IgA production and AID expression. Soluble dietary fiber may improve gut immune function, thereby protecting against bowel pathogens and reducing inflammatory bowel diseases.

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.

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.

Positional differences and aging changes in Japanese woman epidermal thickness and corneous thickness determined by OCT (optical coherence tomography).

BACKGROUND/PURPOSE: A number of studies of the internal structure of Japanese woman's skin are now performed by means of optical coherence tomography (OCT) as a technique capable of visualizing the internal structure in a non-invasive manner. METHODS: We measured the epidermal and corneous thicknesses at 11 sites in 116 healthy female volunteers aged from teens to sixties to examine possible positional differences and aging changes. RESULTS: The epidermal thickness determined at the 11 sites averaged 68.6 ± 23.0 µm (mean ± SD) and the corneous thickness averaged 14.1 ± 1.80 µm, the values of which were thinner than those presented in conventional textbooks on the subject. It was also revealed that, with advancing age, the epidermal thickness becomes less at some sites but showed no change at other sites, and the comparison between age groups suggested that a thinning trend is generally observed up to the thirties with no continuous changes thereafter. CONCLUSION: Aging changes in the epidermis appeared to occur in the granular to basal layers, and the results obtained by OCT, which can viably determine the skin thickness, seemed to be very important for understanding the skin more accurately.

Seasonal and annual variation in the intensity of facial wrinkles.

BACKGROUND/AIMS: We studied annual, seasonal and gender-dependent changes in the intensity of facial wrinkles. METHODS: The study included 32 Japanese subjects (16 men, 16 women, aged 35-47). Wrinkles on the forehead, corner of the eye, lower eyelid and nasolabial groove of each subject were captured in photos and in replicas at 3-month intervals from March, 2009 to March, 2010. At each occasion, skin conductance in the stratum corneum and skin color were measured on the cheek. The photos obtained were used for visual scoring of wrinkle intensity, and the quantitative 3-D data of replicas were obtained. RESULTS: An apparent annual variation in skin conductance, which is supposed to be caused by skin dryness, and in the level of skin brightness, which is supposed to be caused by sun tan, was found for both genders. In contrast, no seasonal changes were determined in wrinkle intensity. Three-D analysis revealed no annual variation in women but revealed annual variation in the depths of eye wrinkles in men. CONCLUSION: There was a gender-dependent difference in the annual variation of wrinkle depth in subjects around 40 years of age. Seasonal environmental changes may affect on the eye wrinkles depth in men within a year.

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.

Neprilysin is identical to skin fibroblast elastase: its role in skin aging and UV responses.

Although human skin fibroblast (HSF) elastase has been characterized as a membrane-bound metalloproteinase, little is known about its structure, amino acid sequence, and encoding gene. As there are similarities in the molecular weights and inhibitory profiles of HSF elastase and neprilysin (neutral endopeptidase 24.11 (NEP)), in this study we tested the hypothesis that they are identical using immunoprecipitation and transfection methods. An immunoprecipitation study demonstrated that HSF elastase activity co-immunoprecipitated with anti-NEP in lysates of cultured HSF. Transfection of an NEP cDNA expression vector into COS-1 cells elicited the expression of HSF elastase and NEP activities in the transfected cells. These findings strongly suggest that HSF elastase is identical to NEP, which functions mainly in neuron-associated cells to degrade neuropeptides. Analysis of the expression pattern of NEP revealed that its expression was remarkably up-regulated at the gene, protein, and enzymatic activity levels during the replicative senescence of cultured HSF. Further, the activity of NEP was markedly enhanced in a pattern similar to elastase activity during the intrinsic aging of mouse skin, in UVA-exposed HSF as well as in HSF treated with conditioned medium from UVB-exposed human keratinocytes. Analysis of the cytokine profile for the stimulation of NEP and HSF elastase activities in HSF demonstrated that among the 11 cytokines tested, IL-1α, IL-1ß, IL-6, IL-8, and GM-CSF had the potential to significantly stimulate both activities similarly, again supporting the identity of HSF elastase and NEP.

Evaluation of photoaging in facial skin by multiphoton laser scanning microscopy.

BACKGROUND/PURPOSE: It has been reported that autofluorescence (AF) and second harmonic generation (SHG) generated in the upper dermis are related with skin photoaging. In this study, we assessed the photoaging of facial skin exposed to daily sunlight using in vivo multiphoton laser microscopy to measure AF and SHG. METHODS: The intensities of AF and SHG in the upper dermis of cheek skin of 56 healthy volunteers aged 20-69 years were measured using a commercially available multiphoton laser microscope (DermaInspect(®) ). Correlations between the photo-signals and volunteer age were calculated. RESULTS: The intensity of SHG and the SHG-to-AF aging index of dermis (SAAID) correlated significantly with age (r=-0.48, -0.67, respectively). CONCLUSION: Our results suggest that SHG and the SAAID index are useful indicators of facial skin aging in vivo.

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.

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.

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.

An investigator blinded cross-over study to characterize the cutaneous effects and suitability of modern sanitary pads for menstrual protection for women residing in the USA.

BACKGROUND: The cutaneous and sensory effects of the practical usage of sanitary pads have been studied globally. However, clinical studies in the United States were conducted only quite a long time ago, and the results of these studies were not published. METHODS: Fifty-four women residing in the United States were asked to use commercially available sanitary pads with a nonwoven unique surface sheet and pads with a perforated film. This was a cross-over study design conducted over the course of two menstrual periods. A board certified dermatologist evaluated the levels of erythema and fissuring, burning, stinging and itching sensations based on clinical observations and interviews. Measurement of pH and swabs for bacteria counting of vulvar skin were also performed. Data from the first clinical evaluation conducted prior to the first menstrual cycle were used as the baseline. At the end of the study, the subjects were asked to complete self-assessment questionnaires about product suitability. RESULTS: Forty-two women (age: 18-50, mean: 37.5) completed the study. No signs of irritation or meaningful differences from the baseline were found in the clinical observations or in the interviews by the dermatologist for either product. No significant difference from baseline was found in the vulvar skin surface pH or in the number of total bacteria for either product. The results of the suitability indicated that the majority of subjects were highly satisfied with both types, but they especially preferred the sanitary pad with a nonwoven unique surface top sheet. CONCLUSION: These results revalidate the results of a previous clinical study in the United States and are consistent with recent reports of worldwide clinical trials of high performance sanitary pads.

Cutaneous and sensory effects of two types of sanitary pads with different surfaces in the Shanghai, Chinese population.

BACKGROUND: Regional differences in practices, ethnicity, and climate may influence the skin compatibility of sanitary pads. Although several clinical trials have been performed in North America, Mexico, Western Europe, Eastern Europe, and Africa, there is no clinical study reported for Asia. OBJECTIVE: The purpose of this study was to examine the skin compatibility of two types of modern sanitary pads in Chinese women along with a dermatological assessment and their satisfaction and preference. MATERIALS AND METHODS: The self-feeling and safety of a new sanitary pad with a non-woven top specially-shaped surface sheet was tested and compared with a conventional sanitary pad with a perforated film top sheet. The subjects studied were 22 Chinese women (age: 20-50 years) with a history of mild and occasional sanitary pad dermatitis residing in Shanghai. One subject wished to discontinue the trial for personal reasons, thus 21 subjects completed the trial. These subjects were randomly assigned to two types of sanitary pads, and used one type during their next menstrual period, and another type during their following menstrual period. After each menstrual period, a dermatologist examined the objective and subjective skin symptoms and determined a score. The subjects were asked to rate their level of satisfaction with respect to overall usability, softness, stickiness, dryness, and absorbency, and to choose which pad they had preferred. RESULTS: No adverse effect was observed for either type of pad. Edema, erythema, burning, and stinging were not obvious symptoms for either type of pad. For itching, 30-65% of the subjects scored slight or mild for both types of pads. A comprehensive evaluation showed that several symptoms were observed on both type of pads at slight and mild levels, but minimal and insignificant differences were found between them. The majority of subjects were highly satisfied with both types, but preferred the new sanitary pad with a non-woven specially-shaped surface top sheet for its softness and absorbency. CONCLUSION: Our results indicate that both types of sanitary pads were tolerated well by Chinese women, thereby providing an important extension of earlier studies.

Mechanistic effects of long-term ultraviolet B irradiation induce epidermal and dermal changes in human skin xenografts.

UVB irradiation has been reported to induce photoaging and suppress systemic immune function that could lead to photocarcinogenesis. However, because of the paucity of an UVB-induced photodamaged skin model, precise and temporal mechanism(s) underlying the deleterious effects of long-term UVB exposure on human skin have yet to be delineated. In this study, we established a model using human skin xenografted onto severe combined immunodeficient mice, which were subsequently challenged by repeated UVB irradiation for 6 weeks. Three-dimensional optical image analysis of skin replicas and noninvasive biophysical measurements illustrated a significant increase in skin surface roughness, similar to premature photoaging, and a significant loss of skin elasticity after long-term UVB exposure. Resembling authentically aged skin, UVB-exposed samples exhibited significant increases in epithelial keratins (K6, K16, K17), elastins, and matrix metalloproteinases (MMP-1, MMP-9, MMP-12) as well as degradation of collagens (I, IV, VII). The UVB-induced deterioration of fibrous keratin intermediate filaments was also observed in the stratum corneum. Additionally, similarities in gene expression patterns between our model and chronologically aged skin substantiated the plausible relationship between photodamage and chronological age. Furthermore, severe skin photodamage was observed when neutralizing antibodies against TIMP-1, an endogenous inhibitor of MMPs, were administered during the UVB exposure regimen. Taken together, these findings suggest that our skin xenograft model recapitulates premature photoaged skin and provides a comprehensive tool with which to assess the deleterious effects of UVB irradiation.

Stem cell factor-KIT signalling plays a pivotal role in regulating pigmentation in mammalian hair.

Hair greying is one of the most distinct but least comprehended features of senescence. The signalling of stem cell factor (SCF) and its receptor KIT has been documented to regulate essential roles in the maintenance of embryonic melanocyte lineages and postnatal cutaneous melanogenesis, although little is known about its detailed mechanisms in postnatal hair pigmentation. To address this, anagen human hair follicles and C57BL/6 murine pelage were analysed in this study. Molecular biological analyses of murine follicular skin indicated a significant increase of membrane-bound SCF expression, reaching its peak 8-16 days after anagen induction in concert with the escalation of cutaneous tyrosinase activity and corresponding pigmentation. Administration of KIT-neutralizing antibody abolished MITF and tyrosinase expressions, resulting in a reversible hair depigmentation in murine regenerated hair and human hair organ culture. Quantitative RT-PCR of human hair follicles indicated that KIT expression as well as the expression of several melanogenic factors, including MITF, was significantly lower in unpigmented than in pigmented follicles. Taken together, these data revealed a pivotal role of SCF-KIT signalling in the maintenance of human hair follicle melanogenesis during the anagen cycle and its involvement in physiological ageing of the hair follicle pigmentary unit.

Imaging of melanin distribution using multiphoton autofluorescence decay curves.

BACKGROUND/PURPOSE: Multiphoton fluorescence lifetime imaging (FLIM) is a technique that produces an image based on differences in the decay rate of fluorescence from a sample. Based on this method, the DermaInspect was developed to observe human skin components non-invasively. In this study, we used the DermaInspect to study melanin in skin. METHODS: A human three-dimensional skin model containing melanocytes was embedded in an OCT compound, frozen and sectioned at 10 microm. The melanin distribution in each section was visualized by the DermaInspect using time-resolved single-photon counting and near-infrared femtosecond laser pulse excitation. The melanin distribution of the same sections was then visualized using the Fontana-Masson staining method. RESULTS: High-resolution images were generated from the ratio of a(1)/a(2) (a(1)e(-) (t/120)+a(2)e(-) (t/1100) was chosen to express the exponential fluorescent decay curve) obtained using the DermaInspect. Granules with a high a(1)/a(2) ratio, approximately 1 mum in diameter, were observed. Fontana-Masson staining identified these granules as melanin. This new technique was then applied for in vivo observation of melanin in human skin. 'Melanin caps' were visualized in the basal cell layer around the nuclei in images derived from the a(1)/a(2) ratio. CONCLUSION: Our study confirms that FLIM can non-invasively provide data of the melanin distribution with almost the same quality as the conventional Fontana-Masson staining method, and demonstrates that FLIM is useful for in vivo observation of melanin granules in human skin.

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.

Functional analysis of keratinocytes in skin color using a human skin substitute model composed of cells derived from different skin pigmentation types.

Skin color is one of the most distinct features in the human race. To assess the mechanisms of skin color variation, human skin substitutes (HSS) were constructed by grafting mixtures of cultured keratinocytes and melanocytes from a combination of donor skin types, together with light skin derived fibroblasts, into chambers inserted onto the back skin of severe combined immunodeficient (SCID) mice. The resulting complexion coloration of the HSS was relatively darker and lighter when dark and light skin derived keratinocytes, respectively, were combined with melanocytes derived from either light or dark skin. The melanin content in the epidermis and the maturation stage of melanosomes in basal keratinocytes were significantly increased in the HSS composed of dark compared to light skin derived keratinocytes. In addition, the ratio of individual/clustered melanosomes in recipient keratinocytes was increased in the former as opposed to the latter HSS. The genetic expression of endothelin-1, proopiomelanocortin, microphthalmia-associated transcription factor, tyrosinase, GP100, and MART1 were increased in HSS composed of dark vs. light skin derived keratinocytes. These data suggest that our HSS is a promising melanogenic model that demonstrates the role of the keratinocyte in regulating in part both melanogenesis and distribution of transferred melanosomes.

Changes of human skin in subepidermal wound healing process.

BACKGROUND/PURPOSE: The wound healing process involves unexplained mechanisms. An aberration in this process is known to cause dermal disorders such as keloid or hypertrophic scars, but the mechanism by which these scars are formed remains to be elucidated. Here we examined the usefulness of a non-invasive optical imaging device to clarify mechanisms of wound healing and of scar formation. METHODS: An 8 mm experimental wound was made in the forearms of six subjects by a suction blister method. To observe chronological changes associated with wound healing, horizontal cross-sectional images were non-invasively obtained of the wounded area from the skin surface down to 129 microm below at 21.5 microm intervals using in vivo laser confocal scanning microscopy (LCSM). RESULTS: The wounds were covered with a new epidermis by week 2, at which time the dermal papilla count decreased while the thickness from the skin surface to the apex of the dermal papilla increased. The count and the thickness returned to the initial levels when the wound was healed. In two out of six subjects, fibrous tissues were observed in the upper dermis, whereas in one other subject, melanocyte-like dendritic cells were observed in the epidermis-dermis border in later phases of wound healing. CONCLUSION: This non-invasive method using in vivo LCSM revealed chronological changes in the dermis and epidermis during wound healing. In addition, although a scar was not formed in any of study subjects, this microscopy revealed aspects similar to the fibrous tissue overgrowth or to melanocyte migration, both of which may relate to wound healing. These results indicate the usefulness of this non-invasive method in studies of wound healing and of scar formation.