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.

Variation in Hsp70-1A Expression Contributes to Skin Color Diversity.

The wide range in human skin color results from varying levels of the pigment melanin. Genetic mechanisms underlying coloration differences have been explored, but identified genes do not account for all variation seen in the skin color spectrum. Post-transcriptional and post-translational regulation of factors that determine skin color, including melanin synthesis in epidermal melanocytes, melanosome transfer to keratinocytes, and melanosome degradation, is also critical for pigmentation. We therefore investigated proteins that are differentially expressed in melanocytes derived from either white or African American skin. Two-dimensional gel electrophoresis and mass spectrometry demonstrated that heat shock protein 70-1A (Hsp70-1A) protein levels were significantly higher in African American melanocytes compared with white melanocytes. Hsp70-1A expression significantly correlated with levels of tyrosinase, the rate-limiting melanogenic enzyme, consistent with a proposed role for Hsp70 family members in tyrosinase post-translational modification. In addition, pharmacologic inhibition and small interfering RNA-mediated downregulation of Hsp70-1A correlated with pigmentation changes in cultured melanocytes, modified human skin substitutes, and ex vivo skin. Furthermore, Hsp70-1A inhibition led to increased autophagy-mediated melanosome degradation in keratinocytes. Our data thus reveal that epidermal Hsp70-1A contributes to the diversity of skin color by regulating the amount of melanin synthesized in melanocytes and modulating autophagic melanosome degradation in keratinocytes.

Cooperation of endothelin-1 signaling with melanosomes plays a role in developing and/or maintaining human skin hyperpigmentation.

Skin hyperpigmentation is characterized by increased melanin synthesis and deposition that can cause significant psychosocial and psychological distress. Although several cytokine-receptor signaling cascades contribute to the formation of ultraviolet B-induced cutaneous hyperpigmentation, their possible involvement in other types of skin hyperpigmentation has never been clearly addressed. Since our continuous studies using skin specimens from more than 30 subjects with ethnic skin diversity emphasized a consistent augmentation in the expression of endothelin-1 (ET-1) and its receptor (Endothelin B receptor, ET-B) in hyperpigmented lesions, including senile lentigos (SLs), the precise function of ET-1 signaling was investigated in the present study. In line with previous studies, ET-1 significantly induced melanogenesis followed by increases in melanosome transport in melanocytes and in its transfer to keratinocytes while inhibition of ET-B function substantially depressed melanogenic ability in tissue-cultured SLs. Additionally, in agreement with a previous report that the formation of autophagosomes rather than melanosomes is stimulated according to starvation or defective melanosome production, ET-1 was found to remarkably augment the expression of components necessary for early melanosome formation, indicating its counteraction against autophagy-targeting melanosome degradation in melanocytes. Despite the lack of substantial impact of ET-1 on keratinocyte melanogenic functions, the expression of ET-1 was enhanced following melanosome uptake by keratinocytes. Taken together, our data suggest that ET-1 plays a substantial role in the development and/or maintenance of skin hyperpigmentation in reciprocal cooperation with increased melanosome incorporation.

Evaluation of unique elastic aggregates (elastic globes) in normal facial skin by multiphoton laser scanning tomography.

BACKGROUND: There is no reliable marker to estimate the degree of skin aging in vivo. It now has become possible to quantitatively determine the dermal characteristics of the extracellular matrix (ECM) in vivo using multiphoton laser tomography (MLT). METHODS: Fifty-seven healthy Japanese female volunteers, aged from 20 to 60 years old, were examined using multiphoton depth-resolved measurements of autofluorescence (AF) and second harmonic generation (SHG) at three sites on their right cheek. Paraffin-embedded skin specimens obtained from the faces of 12 normal individuals aged 38-68 years old were stained with Elastica van Gieson (EVG). RESULTS: We found unique elastic aggregates at a 20 µm depth from the dermo-epidermal junction (DEJ) in vivo which increased in size with aging of subjects from 20 to 60 years old. SHG fibers seemed to surround those elastic aggregates. Histological examination of specimens from normal individuals stained with EVG confirmed the occurrence of elastic aggregates with varied sizes just beneath the epidermis or hair follicles. CONCLUSIONS: The elastic aggregates are morphologically similar to previously described 'elastic globes' and can serve as a marker of the early stage of photoaging. MLT will contribute to determine age-related dermal changes using a non-invasive technique.

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.

Autophagy has a significant role in determining skin color by regulating melanosome degradation in keratinocytes.

Melanin in the epidermis determines the wide variation in skin color associated with ethnic skin diversity. Ethnic differences exist regarding melanosome loss in keratinocytes, but the mechanisms underlying these differences, and their contribution to the regulation of skin color, remain unclear. Here, we explored the involvement of autophagy in determining skin color by regulating melanosome degradation in keratinocytes. Keratinocytes derived from Caucasian skin exhibit higher autophagic activity than those derived from African American (AA) skin. Furthermore, along with the higher autophagy activity in Caucasian skin-derived keratinocytes compared with AA skin-derived keratinocytes, Caucasian skin-derived keratinocytes were more sensitive to melanosome treatment as shown by their enhanced autophagic activity, which may reflect the substantial mechanisms in the human epidermis owing to the limitations of the models. Melanosome accumulation in keratinocytes was accelerated by treatment with lysosomal inhibitors or with small interfering RNAs specific for autophagy-related proteins, which are essential for autophagy. Furthermore, consistent with the alterations in skin appearance, the melanin levels in human skin cultured ex vivo and in human skin substitutes in vitro were substantially diminished by activators of autophagy and enhanced by the inhibitors. Taken together, our data reveal that autophagy has a pivotal role in skin color determination by regulating melanosome degradation in keratinocytes, and thereby contributes to the ethnic diversity of skin color.

Improvement of crow's feet lines by topical application of 1-carbamimidoyl-L-proline (CLP).

Wrinkles, one of the characteristics of chronic sun-damaged and/or aged skin, are associated with psychological distress. Apart from the deterioration of collagen and elastic fibers in the dermis, which induces the loss of skin elasticity, it has been recently proposed that decreased flexibility or elasticity of the stratum corneum (SC) is also correlated with wrinkle formation. The elasticity of the SC has been shown to be regulated, at least in part, by the amounts and types of amino acids. To evaluate the ability of our newly developed amino acid-derivative (1-carbamimidoyl-L-proline; CLP), which recovers the elastic properties of the SC ex vivo, to improve wrinkles, a clinical test was performed with 126 Japanese female subjects aged 32-50 years who had crow's feet lines on their faces. Three eligible dermatologists evaluated the study according to authorized grades by the Japanese Cosmetic Science Society and scored the subjects who were much improved or improved as 29.7% and 57.8% of all CLP-treated subjects at 4 and 8 weeks, respectively. In contrast, only 1.5% and 8.1% of subjects improved with the placebo lotion at 4 and 8 weeks, respectively. These results suggest a significant efficacy of CLP to improve wrinkles. In parallel with the dermatologists' assessments, skin surface roughness in the CLP-treated group was significantly reduced after treatment with CLP for 4 and 8 weeks compared to the placebo-treated group. The sum of these data suggests that CLP is a promising and useful ingredient for the improvement of wrinkles through its ability to enhance the elasticity of the SC.

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.

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.

Dry skin in the winter is related to the ceramide profile in the stratum corneum and can be improved by treatment with a Eucalyptus extract.

BACKGROUND: Dry skin in the winter has been reported to involve scaling, defects in water holding and barrier functions, and decreased ceramide (CER) levels in the stratum corneum (SC). We previously reported that a Eucalyptus extract promotes CER synthesis in cultured keratinocytes and accelerates the recovery of hydration in a barrier-disrupted model of human skin. AIMS: One of the objectives was to examine the CER profile and its contribution to the relief of dry skin. The other objective was to assess the efficacy of a Eucalyptus extract to treat dry skin. PATIENTS/METHODS: Twenty subjects with dry skin on their legs were assessed and their CER profiles were analyzed using tape-stripping. A moisturizer with a Eucalyptus extract was assessed for its effects on dry skin using a leg regression methodology comprising 28 days of treatment and 14 days of regression. RESULTS: Indicators of dry skin conditions (conductance, dryness, roughness, and scaliness) strongly correlated with the level of CER, CER [NP], and CER[NH]. Treatment with the Eucalyptus extract significantly improved conductance (3 days after regression) and transepidermal water loss (14 days after regression) compared with the placebo. After 28 days of treatment with the Eucalyptus extract, the level of CER in the SC did not increase, but CER [NP] did increase. CONCLUSIONS: These results suggest that not only the level of CER, but also specific CER species strongly contribute to dry skin relief and products that increase those are useful to improve dry skin conditions.

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.

Study of the vulvar skin in healthy Japanese women: components of the stratum corneum and microbes.

BACKGROUND: Although the physiological conditions of vulvar skin in Caucasian populations have been characterized, little is known about these conditions in Japanese women. METHODS: Skin of the labia, groin, mons pubis, and inner thigh was examined in 40 healthy Japanese women outwith their menstrual period. Skin moisture, skin pH, ceramide content and inflammatory cytokine proteins of the stratum corneum, and bacterial flora were assessed. RESULTS: Skin moisture was found to be significantly lower in the labia than at the other three sites examined. No differences were found in skin pH. A significant difference in ceramide content was observed between the groin and inner thigh. The ratio of interleukin-1α (IL-1α) and interleukin-1α receptor antagonist (IL-1Ra) was significantly higher in the labia than in the other sites. Numbers of total bacteria, Staphylococcus epidermis, and Lactobacillus spp. were greater in the labia and mons pubis sites compared with the inner thigh. Prevotella spp. were found only in the labia. CONCLUSIONS: In Japanese women, the skin at the labia is drier and more inflammatory than the skin at the groin, mons pubis, and inner thigh; this cannot be explained by the ceramide content and/or pH of the stratum corneum. Prevotella spp. may perform a key role in the vulvar skin of Japanese women.

Green tea extract suppresses adiposity and affects the expression of lipid metabolism genes in diet-induced obese zebrafish.

BACKGROUND: Visceral fat accumulation is one of the most important predictors of mortality in obese populations. Administration of green tea extract (GTE) can reduce body fat and reduce the risk of obesity-related diseases in mammals. In this study, we investigated the effects and mechanisms of GTE on adiposity in diet-induced obese (DIO) zebrafish. METHODS: Zebrafish at 3.5 to 4.5 months post-fertilization were allocated to four groups: non-DIO, DIO, DIO + 0.0025%GTE, and DIO + 0.0050%GTE. The non-DIO group was fed freshly hatched Artemia once daily (5 mg cysts/fish daily) for 40 days. Zebrafish in the three DIO groups were fed freshly hatched Artemia three times daily (60 mg cysts/fish daily). Zebrafish in the DIO + 0.0025%GTE and DIO + 0.0050%GTE groups were exposed to GTE after the start of feeding three times daily for 40 days. RESULTS: Three-dimensional microcomputed tomography analysis showed that GTE exposure significantly decreased the volume of visceral but not subcutaneous fat tissue in DIO zebrafish. GTE exposure increased hepatic expression of the lipid catabolism genes ACOX1 (acyl-coenzyme A oxidase 1, palmitoyl), ACADM (acyl-coenzyme A dehydrogenase, c-4 to c-12 straight chain), and PPARA (peroxisome proliferator-activated receptor alpha). GTE exposure also significantly decreased the visceral fat expression of SOCS3 (suppressor of cytokine signaling 3b) which inhibits leptin signaling. CONCLUSIONS: The present results are consistent with those seen in mammals treated with GTE, supporting the validity of studying the effects of GTE in DIO zebrafish. Our results suggest that GTE exerts beneficial effects on adiposity, possibly by altering the expression of lipid catabolism genes and SOCS3.

Essential role of RAB27A in determining constitutive human skin color.

Human skin color is predominantly determined by melanin produced in melanosomes within melanocytes and subsequently distributed to keratinocytes. There are many studies that have proposed mechanisms underlying ethnic skin color variations, whereas the processes involved from melanin synthesis in melanocytes to the transfer of melanosomes to keratinocytes are common among humans. Apart from the activities in the melanogenic rate-limiting enzyme, tyrosinase, in melanocytes and the amounts and distribution patterns of melanosomes in keratinocytes, the abilities of the actin-associated factors in charge of melanosome transport within melanocytes also regulate pigmentation. Mutations in genes encoding melanosome transport-related molecules, such as MYO5A, RAB27A and SLAC-2A, have been reported to cause a human pigmentary disease known as Griscelli syndrome, which is associated with diluted skin and hair color. Thus we hypothesized that process might play a role in modulating skin color variations. To address that hypothesis, the correlations of expression of RAB27A and its specific effector, SLAC2-A, to melanogenic ability were evaluated in comparison with tyrosinase, using human melanocytes derived from 19 individuals of varying skin types. Following the finding of the highest correlation in RAB27A expression to the melanogenic ability, darkly-pigmented melanocytes with significantly higher RAB27A expression were found to transfer significantly more melanosomes to keratinocytes than lightly-pigmented melanocytes in co-culture and in human skin substitutes (HSSs) in vivo, resulting in darker skin color in concert with the difference observed in African-descent and Caucasian skins. Additionally, RAB27A knockdown by a lentivirus-derived shRNA in melanocytes concomitantly demonstrated a significantly reduced number of transferred melanosomes to keratinocytes in co-culture and a significantly diminished epidermal melanin content skin color intensity (ΔL* = 4.4) in the HSSs. These data reveal the intrinsically essential role of RAB27A in human ethnic skin color determination and provide new insights for the fundamental understanding of regulatory mechanisms underlying skin pigmentation.

The endogenous protease inhibitor TIMP-1 mediates protection and recovery from cutaneous photodamage.

UVB exposure is well known to induce skin photodamage and photoaging that correlates with qualitative and quantitative deterioration of the dermal extracellular matrix (ECM) because of the upregulation of matrix metalloproteinases (MMPs). Although inhibitory effects of tissue inhibitor of metalloproteinases (TIMPs) on most MMPs have been reported, the protective role of TIMP-1 against photodamage is poorly understood. To address this, TIMP-1 function was augmented or abolished in a human skin xenograft photodamage model after the confirmation of significantly diminished TIMP-1 expression both in photoaged and intrinsically aged skins. During a chronic UVB exposure regimen, pre-treatment with a lentiviral vector overexpressing TIMP-1 or concomitant administration of an anti-TIMP-1-neutralizing antibody (NAB) led to photoprotection or more severe photodamage, respectively. Overexpression of TIMP-1 resulted in significant inhibition of UVB-induced ECM degradation, as well as suppression of decreased skin elasticity and roughness, whereas the NAB-mediated inhibition of TIMP-1 had opposite effects. Furthermore, UVB-induced production of the pro-inflammatory cytokine, tumor necrosis factor α, was inhibited by TIMP-1 treatment of human keratinocytes. Taken together, these data shed light on the important role of TIMP-1 in protection and recovery from cutaneous photodamage because of its suppression of ECM degradation and inflammation.

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.

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.