Biology of estrogens in skin: implications for skin aging

Testosterone-to-oestradiol ratio is associated with female facial attractiveness

The relationship between facial shape and attractiveness has been extensively studied, yet few studies have investigated the underlying biological factors of an attractive face. Many researchers have proposed a link between female attractiveness and sex hormones, but there is little empirical evidence in support of this assumption. In the present study we investigated the relationship between circulating sex hormones and attractiveness. We created prototypes by separately averaging photographs of 15 women with high and low levels of testosterone, oestradiol, and testosterone-to-oestradiol ratio levels, respectively. An independent set of facial images was then shape transformed toward these prototypes. We paired the resulting images in such a way that one face depicted a female with high hormone level and the other one with a low hormone level. Fifty participants were asked to choose the more attractive face of each pair. We found that low testosterone-to-oestradiol ratio and low testosterone were positively associated with female facial attractiveness. There was no preference for faces with high oestradiol levels. In an additional experiment with 36 participants we confirmed that a low testosterone-to-oestradiol ratio plays a larger role than low testosterone alone. These results provide empirical evidence that an attractive female face is shaped by interacting effects of testosterone and oestradiol.

Effects of selective MMP-13 inhibition in squamous cell carcinoma depend on estrogen

Matrix metalloproteinases like MMP-13 cleave and remodel the extracellular matrix and thereby play a crucial role in tumor progression in vivo. Using a highly selective inhibitor to block MMP-13 protein activity, we demonstrate a striking inhibitory effect on invasive tumor growth and vascularization in murine skin squamous cell carcinoma (SCC). Therapy outcome critically depends on animal age in C57Bl/6 mice and was successful in old female but not in young female mice. Treatment success was recovered by ovariectomy in young and abolished by 17ß-estradiol supplementation in old mice, suggesting a hormone dependent inhibitor effect. Responsiveness of the tumorigenic keratinocytes BDVII and fibroblasts to 17ß-estradiol was confirmed in vitro, where MMP-13 inhibitor treatment led to a reduction of cell invasion and vascular endothelial growth factor (VEGF) release. This correlated well with a less invasive and vascularized tumor in treated mice in vivo. 17ß-estradiol supplementation also reduced invasion and VEGF release in vitro with no additional reduction on MMP-13 inhibitor treatment. This suggests that low 17ß-estradiol levels in old mice in vivo lead to enhanced MMP-13 levels and VEGF release, allowing a more effective inhibitor treatment compared to young mice. In our study, we present a strong link between lower estrogen levels in old female mice, an elevated MMP-13 level, which results in a more effective MMP-13 inhibitor treatment in fibroblasts and SCC cells in vitro and in vivo.

Stem cell and extracellular matrix-related molecules increase following melatonin treatment in the skin of postmenopausal rats

The menopause has a negative effect in the skin. Melatonin affects skin functions and structures through actions mediated by cell-surface and putative-nuclear receptors expressed in skin cell. We have therefore determined the effects of melatonin treatment on stem cell in the epidermis and extracellular matrix related molecules in the dermis the skin of postmenopausal rats. A total of 45 female rats were divided into 5 groups: control group, group A [ovariectomy (OVX)], group B (OVX +10 mg/kg/day melatonin), group C (OVX +30 mg/kg/day melatonin), group S (sham operated + 10 mg/kg/day melatonin). Ventral skin samples were excised at 12th week after ovariectomy. Hematoxylin-eosin, periodic acid- methylamine silver, elastic van Gieson staining techniques were used to measure histomorphometrically the thickness of elastic fibers and basement membrane, depths of the epidermis, dermis, and subcutaneous fat layer. Immunohistochemical staining methods were used for fibroblast growth factor β (FGF β), collagen type I, fibronectin, β-catenin, c-kit, c-Myc evaluation. Epidermal thickness, subcutaneous fat layer, and elastic fibers were significantly decreased in group C, and there was a significant increase after melatonin treatment. Although there was no difference in dermal thickness of group C, melatonin also significantly increased the dermal thickness. High FGF β, type I collagen, fibronectin, β-catenin, c-Myc immunoreactivity developed following melatonin in all groups. Thus melatonin treatment of postmenopausal rats was mostly due to the decrease of stem cell and extracellular matrix-related molecules in the skin.

Asymmetric facial skin viscoelasticity during climacteric aging

Background

Climacteric skin aging affects certain biophysical characteristics of facial skin. The purpose of the present study was to assess the symmetric involvement of the cheeks in this stage of the aging process.

Methods

Skin viscoelasticity was compared on both cheeks in premenopausal and post-menopausal women with indoor occupational activities somewhat limiting the influence of chronic sun exposure. Eighty-four healthy women comprising 36 premenopausal women and 48 early post-menopausal women off hormone replacement therapy were enrolled in two groups. The tensile characteristics of both cheeks were tested and compared in each group. A computerized suction device equipped with a 2 mm diameter hollow probe was used to derive viscoelasticity parameters during a five-cycle procedure of 2 seconds each. Skin unfolding, intrinsic distensibility, biological elasticity, and creep extension were measured.

Results

Both biological elasticity and creep extension were asymmetric on the cheeks of the post-menopausal women. In contrast, these differences were more discrete in the premenopausal women.

Conclusion

Facial skin viscoelasticity appeared to be asymmetric following menopause. The possibility of asymmetry should be taken into account in future studies of the effects of hormone replacement therapy and any antiaging procedure on the face in menopausal women.

The development of hyperbaric oxygen therapy for skin rejuvenation and treatment of photoaging

Hyperbaric oxygen therapy (HBOT), a therapy that have patients breath in pure oxygen in a pressurized chamber, has been long used as a treatment for conditions such as decompression sickness and carbon monoxide poisoning. Oxygen recently has been found to be an important component in skin rejuvenation, treatment of photoaging skin, and improvement in skin complexions. The interest in the use of HBOT for this purpose is continually growing and becoming more widespread. In addition to aging and genetic makeup, chronic UV radiation due to everyday exposure, especially UV-B, can greatly increase the rate of wrinkle formation through increasing skin angiogenesis and degradation of extracellular matrix molecules. The use of HBOT and hyperoxia conditions has been found to attenuate the formation of wrinkles from UV irradiation. It accomplishes the task by possibly inhibiting various processes and pathways involved such as the HIF1-α, VEGF, neutrophil infiltrations, and MMP-2 & MMP-9, which are directly involved with promoting skin angiogenesis in its active state. There are currently medical aesthetic clinics that are using oxygen therapy under high pressure applied directly to skin to reduce visible wrinkles but this procedure is not widespread yet due to more research that needs to be done on this topic. However, this treatment for wrinkles is definitely growing due to recent studies done showing the effectiveness of oxygen therapy on wrinkles. This review article will explore and summarize researches done on possible mechanisms dealing with the use of oxygen therapy for reduction of UVB-caused wrinkles, its side effects, and its possible future improvement and use in medicine.

The dietary ingredient, genistein, stimulates cathelicidin antimicrobial peptide expression through a novel S1P-dependent mechanism

We recently discovered that a signaling lipid, sphingosine-1-phosphate (S1P), generated by sphingosine kinase 1, regulates a major epidermal antimicrobial peptide's [cathelicidin antimicrobial peptide (CAMP)] expression via an NF-κB→C/EBPα-dependent pathway, independent of vitamin D receptor (VDR) in epithelial cells. Activation of estrogen receptors (ERs) by either estrogens or phytoestrogens also is known to stimulate S1P production, but it is unknown whether ER activation increases CAMP production. We investigated whether a phytoestrogen, genistein, simulates CAMP expression in keratinocytes, a model of epithelial cells, by either a S1P-dependent mechanism(s) or the alternate VDR-regulated pathway. Exogenous genistein, as well as an ER-β ligand, WAY-200070, increased CAMP mRNA and protein expression in cultured human keratinocytes, while ER-β antagonist, ICI182780, attenuated the expected genistein- and WAY-200070-induced increase in CAMP mRNA/protein expression. Genistein treatment increased acidic and alkaline ceramidase expression and cellular S1P levels in parallel with increased S1P lyase inhibition, accounting for increased CAMP production. In contrast, siRNA against VDR did not alter genistein-mediated up-regulation of CAMP. Taken together, genistein induces CAMP production via an ER-β→S1P→NF-κB→C/EBPα- rather than a VDR-dependent mechanism, illuminating a new role for estrogens in the regulation of epithelial innate immunity and pointing to potential additional benefits of dietary genistein in enhancing cutaneous antimicrobial defense.

Histological investigation of the effect of soybean (Glycine max) extracts on the collagen layer and estrogen receptors in the skin of female rats

OBJECTIVES

The purpose of this study was to analyze the effects of soybean extracts obtained using different extraction methods on the skin of female rats.

METHOD

A total of 64 female Sprague-Dawley rats were divided into 8 equal groups. Various extracts were administered to the female rats by oral gavage for one month. The groups comprised carboxymethyl cellulose-free control, carboxymethyl cellulose-plus control, 100-mg/kg n-hexane extract, 200-mg/kg n-hexane extract, 100-mg/kg ethyl acetate extract, 200-mg/kg ethyl acetate extract, 100-mg/kg ethanol extract and 200-mg/kg ethanol extract groups. The thickness of the collagen layer and the number of estrogen receptor-positive cells were evaluated.

RESULTS

All the extract-treated groups showed a statistically significant decrease in the number of estrogen receptor-positive cells compared with the control groups. Regarding the thickness of the collagen layer, only the 200-mg/kg ethyl acetate extract-treated group showed a significant increase compared with the control groups (p<0.05).

CONCLUSIONS

Our data suggest that oral intake of three different total soybean extracts might have positive estrogenic effects on the skin and that only a high-dose ethyl acetate extract can increase the expression of collagen, which may prove to be beneficial for postmenopausal facial skin.

Revisiting the cutaneous impact of oral hormone replacement therapy

Menopause is a key point moment in the specific aging process of women. It represents a universal evolution in life. Its initiation is defined by a 12-month amenorrhea following the ultimate menstrual period. It encompasses a series of different biologic and physiologic characteristics. This period of life appears to spot a decline in a series of skin functional performances initiating tissue atrophy, withering, and slackness. Any part of the skin is possibly altered, including the epidermis, dermis, hypodermis, and hair follicles. Hormone replacement therapy (oral and nonoral) and transdermal estrogen therapy represent possible specific managements for women engaged in the climacteric phase. All the current reports indicate that chronologic aging, climacteric estrogen deficiency, and adequate hormone therapy exert profound effects on various parts of the skin.

Protective effects of equol and their polyphenolic isomers against dermal aging: microarray/protein evidence with clinical implications and unique delivery into human skin

CONTEXT

Equol is a polyphenolic/isoflavonoid molecule that can be expressed as isomers. However, the characteristics of the equol isomers on dermal gene/protein expression and human skin percutaneous absorption remain unknown.

OBJECTIVE

Perform a comprehensive investigation on equol as: R-equol, racemic equol or S-equol to determine their differential expression of skin-related genes, quantify collagen expression and determine percutaneous absorption in human skin.

METHODS

Quantified: (i) gene expression/mRNA levels via gene array technology using human skin equivalents with equol exposure at 1.2% in qPCR experiments, (ii) in vitro collagen expression in human fibroblasts, and (iii) percutaneous absorption by Franz cell techniques.

RESULTS

In the qPCR studies, only three genes displayed the greatest significant expression by S-equol, whereas 16 genes displayed the greatest significant levels (either stimulation or inhibition) by R-equol and/or racemic equol, such as extracellular matrix proteins (i.e., collagen and elastin), nerve growth factor, aging genes [FOS, 100 A8 and A9 calcium-binding proteins, 5α-reductase type 1, and matrix metalloproteinases (1, 3, and 9)], and inflammatory genes (e.g., interleukin-1 alpha, interleukin-6, and cyclooxygenase-1). Collagen type I expression in fibroblasts was greater with racemic versus S-equol treatment at 1 and 10 nM. Percutaneous absorption demonstrated high sequestering in keratinocytes with subsequent accumulation/release over time.

DISCUSSION AND CONCLUSION

Overall, these results illustrate the significant differences in mirror-image molecules or isomers of equol where R-equol and/or racemic equol are better molecules for skin gene expression compared to S-equol and the percutaneous absorption of equol represents a unique epidermal reservoir delivery mechanism.

Expression and roles of steroidogenic acute regulatory (StAR) protein in 'non-classical', extra-adrenal and extra-gonadal cells and tissues

The activity of the steroidogenic acute regulatory (StAR) protein is indispensable and rate limiting for high output synthesis of steroid hormones in the adrenal cortex and the gonads, known as the 'classical' steroidogenic organs (StAR is not expressed in the human placenta). In addition, studies of recent years have shown that StAR is also expressed in many tissues that produce steroid hormones for local use, potentially conferring some functional advantage by acting via intracrine, autocrine or paracrine fashion. Others hypothesized that StAR might also function in non-steroidogenic roles in specific tissues. This review highlights the evidence for the presence of StAR in 17 extra-adrenal and extra-gonadal organs, cell types and malignancies. Provided is the physiological context and the rationale for searching for the presence of StAR in such cells. Since in many of the tissues the overall level of StAR is relatively low, we also reviewed the methods used for StAR detection. The gathered information suggests that a comprehensive understanding of StAR activity in 'non-classical' tissues will require the use of experimental approaches that are able to analyze StAR presence at single-cell resolution.

Aging in elderly: chronological versus photoaging

Background:

Skin is a window to aging changes, a biological reality. There is a dearth of studies regarding the various chronological (intrinsic) aging and photoaging (extrinsic) changes seen in Asians. This study was undertaken to detect the clinical pattern of aging skin changes and dermatoses seen in the elderly.

Materials and Methods:

This was a descriptive study conducted on 500 consecutive elderly individuals attending the Dermatology out-patient department. The severity of photoaging was graded using Glogau scale.

Results:

Most of the population had skin type IV and V. Majority (415, 83%) of our cases had chronological aging without photoaging and the remaining 85 (17%) individuals had photoaging along with chronological aging. The common skin changes due to chronological aging were thin skin, fine wrinkles, xerosis, and loss of elasticity. Photoaging changes such as dyspigmentation, freckles, thick skin, deep wrinkles, melasma, citrine skin, senile purpura, pseudostellate scar, acrokeratoelastoidosis marginalis, and lentigines were less frequent in our study. Smoking and prolonged sun exposure was the risk factors aggravating photoaging. The most common dermatosis was pruritus in 248 (49.6%) individuals, of which 149 (29.8%) had pruritus associated with xerosis. Contact dermatitis was more common in males. Fungal infections were frequently seen in females. Seborrhoeic keratosis (253, 50.6%) was the most common benign neoplasm more commonly seen in males. Cutaneous malignancies were less common in our study population.

Conclusion:

Photoaging changes were less common than chronological aging changes in skin type IV. Chronological changes were more frequent in females than males, while photoaging was more frequent in males.

Sex steroid synthesis in human skin in situ: the roles of aromatase and steroidogenic acute regulatory protein in the homeostasis of human skin

Sex steroids have been known to play important roles in the homeostasis of human skin, but little is known about their biosyntheses in that tissue. In this study, we characterized the correlation between the concentrations of sex steroids and the expression levels of the factors involved in their synthesis or metabolism in human skin. The expression levels of aromatase (ARO) and steroidogenic acute regulatory protein (StAR) were positively correlated with estrogens and testosterone concentrations, respectively. We demonstrated that estrogen synthesis was markedly decreased by ARO inhibitor and that skins with higher ARO expression had thicker elastic fibers than those with lower ARO expression. While pregnenolone and testosterone concentrations were increased by cholesterol administration to epidermal keratinocytes. Scalp skin with higher StAR expression was cleared to have significantly fewer hair follicles than that with lower expression. Our results suggest that the status of ARO and StAR contribute to estrogen synthesis in situ, especially for the regulation of elastic fiber formation, and to testosterone synthesis, which may be associated with hair growth, respectively.

Evaluation of ultrasonography for measurement of skin thickness in Shar-Peis

OBJECTIVE

To determine whether high-frequency diagnostic ultrasonography is useful for assessment of skin thickness in Shar-Peis.

ANIMALS

10 healthy Shar-Peis and 10 healthy Beagles used as controls.

PROCEDURES

Ultrasonographic examination of the skin was performed on 4 cutaneous sites by use of a 13-MHz linear-array transducer, and the mean of 3 measurements was calculated. Ultrasonography results were compared with histologic findings of skin specimens stained with H&E, Alcian blue at a pH of 2.5, and Masson trichrome stains, with histometric measurements of skin thickness made by use of a microscope, and with measurements of skin thickness made by use of a plicometer. Ultrasonograpy results were also compared via age and sex of selected animals.

RESULTS

A clear correlation was detected between ultrasonography results and results of histologic and histometric analysis in both groups. In Shar-Peis, no correlation was found between ultrasonography results and age and sex, whereas in Beagles, a weak positive correlation was found only between skin thickness in dorsal cervical and frontal (on the rostral margins of the supraorbital processes) regions and age. A positive overall correlation was found in Shar-Peis between measurements made via ultrasonography and plicometery.

CONCLUSIONS AND CLINICAL RELEVANCE

Ultrasonography was a useful tool to assess skin thickness, and in Shar-Peis, it might be considered a valid alternative to invasive methods such as histologic examination to objectively estimate the severity of hereditary cutaneous hyaluronosis.

A role for estrogen receptor-α and estrogen receptor-β in collagen biosynthesis in mouse skin

Hormonal regulation of the dermal collagenous extracellular matrix plays a key role in maintaining proper tissue homeostasis, however the factors and pathways involved in this process are not fully defined. This study investigated the role of estrogen receptors (ERs) in the regulation of collagen biosynthesis in mice lacking ERα or ERβ. Collagen content was significantly increased in the skin of ΕRα^-/- mice as measured by acetic acid extraction and the hydroxyproline assay and correlated with the decreased levels of MMP-15 and elevated collagen production by ΕRα^-/- fibroblasts. In contrast, collagen content was decreased in the skin of ERβ^-/- mice despite markedly increased collagen production by ERβ^-/- fibroblasts. However, expression of several matrix metalloproteinases (MMPs), including MMP-8 and -15 was significantly elevated suggesting increased degradation of dermal collagen. Furthermore, ERβ^-/- mice were characterized by significantly reduced levels of small leucine proteoglycans (SLRPs), lumican and decorin, leading to the defects in collagen fibrillogenesis and possibly less stable collagen fibrils. ERα^-/- mice also exhibited fibrils with irregular structure and size, which correlated with increased levels of lumican and decorin. Together, these results demonstrate distinct functions of estrogen receptors in the regulation of collagen biosynthesis in mouse skin in vivo.

Skin anti-aging strategies

Skin aging is a complex biological process influenced by a combination of endogenous or intrinsic and exogenous or extrinsic factors. Because of the fact that skin health and beauty is considered one of the principal factors representing overall "well-being" and the perception of "health" in humans, several anti-aging strategies have been developed during the last years. It is the intention of this article to review the most important anti-aging strategies that dermatologists have nowadays in hand, including including preventive measurements, cosmetological strategies, topical and systemic therapeutic agents and invasive procedures.

Estradiol protects dermal hyaluronan/versican matrix during photoaging by release of epidermal growth factor from keratinocytes

Hyaluronan (HA) and versican are key components of the dermis and are responsive to ultraviolet (UV)B-induced remodeling. The aim of this study was to explore the molecular mechanisms mediating the effects of estrogen (E(2)) on HA-rich extracellular matrix during photoaging. Hairless skh-1 mice were irradiated with UVB (three times, 1 minimal erythema dose (80 mJ/cm(2)), weekly) for 10 weeks, and endogenous sex hormone production was abrogated by ovariectomy. Subcutaneous substitution of E(2) by means of controlled-release pellets caused a strong increase in the dermal HA content in both irradiated and nonirradiated skin. The increase in dermal HA correlated with induction of HA synthase HAS3 by E(2). Expression of splice variant 2 of the HA-binding proteoglycan versican was also increased by E(2). In search of candidate mediators of these effects, it was found that E(2) strongly induced the expression of epidermal growth factor (EGF) in UVB-irradiated epidermis in vivo and in keratinocytes in vitro. EGF in turn up-regulated the expression of HAS3 and versican V2 in dermal fibroblasts. HAS3 knockdown by shRNA caused inhibition of fibroblast proliferation. Furthermore, HAS3 and versican V2 induction by E(2) correlated positively with proliferation in vivo. In addition, the accumulation of inflammatory macrophages, expression of inducible cyclooxygenase 2, as well as proinflammatory monocyte chemotactic protein 1 were decreased in response to E(2) in the dermis. Collectively, these data suggest that E(2) treatment increases the amount of dermal HA and versican V2 via paracrine release of EGF, which may be implicated in the pro-proliferative and anti-inflammatory effects of E(2) during photoaging.

Tissue-Specific Effects of Loss of Estrogen during Menopause and Aging

The roles of estrogens have been best studied in the breast, breast cancers, and in the female reproductive tract. However, estrogens have important functions in almost every tissue in the body. Recent clinical trials such as the Women's Health Initiative have highlighted both the importance of estrogens and how little we know about the molecular mechanism of estrogens in these other tissues. In this review, we illustrate the diverse functions of estrogens in the bone, adipose tissue, skin, hair, brain, skeletal muscle and cardiovascular system, and how the loss of estrogens during aging affects these tissues. Early transcriptional targets of estrogen are reviewed in each tissue. We also describe the tissue-specific effects of selective estrogen receptor modulators (SERMs) used for the treatment of breast cancers and postmenopausal symptoms.

Genistein aglycone, a soy-derived isoflavone, improves skin changes induced by ovariectomy in rats

BACKGROUND AND PURPOSE

Ovariectomy accelerates age-related skin changes as adequate oestrogen levels are required to control structural integrity and functional capacity of skin. Genistein, a soy-derived isoflavone, has been tested in anti-ageing cosmetic preparations with interesting results on skin elasticity, photoaging and skin cancer prevention. We investigated the effects of genistein aglycone and compared them with systemic raloxifene hydrochloride and 17-α-ethinyloestradiol on skin changes in aged, ovariectomized (OVX) rats.

EXPERIMENTAL APPROACH

Six months after ovariectomy, rats were randomly allocated to different groups and treated, daily, with genistein aglycone (1 and 10mg·kg(-1) s.c.), raloxifene hydrochloride (0.05 and 0.5mg·kg(-1) s.c.) or 17-α-ethinyloestradiol (0.003 and 0.03mg·kg(-1) s.c.) for 12 weeks. Controls were untreated OVX and sham OVX rats. At the end of the treatment period, a skin biopsy was carried out and skin samples were assessed for molecular, histological and functional changes.

KEY RESULTS

Skin samples of untreated OVX rats showed a decrease in TGF-β1, VEGF, MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 compared with sham OVX rats. All the treatments significantly restored this depressed molecular profile revealed in OVX rats. Genistein aglycone, 1mg·kg(-1) , also significantly increased the thickness of collagen and breaking strength of skin in the OVX rats.

CONCLUSIONS AND IMPLICATIONS

Relatively long-term, systemic treatment with genistein aglycone shows comparable efficacy to oestrogen in reversing some molecular, histological and functional changes of the skin associated with ovariectomy in aged rats. This suggests that genistein aglycone might be an effective alternative therapy for the management of age-related skin changes in postmenopausal women.

Biochemical investigation and gene analysis of equol: a plant and soy-derived isoflavonoid with antiaging and antioxidant properties with potential human skin applications

The purpose of this study was to investigate the effects of equol, a plant and intestinal flora derived isoflavonoid molecule on the expression of skin genes and proteins using human dermal models. As equol has been shown to mimic 17β-estradiol and bind specifically to 5α-dihydrotestostone (5α-DHT), these agents were used (in addition to equol) to determine whether equol may play important and beneficial roles in the extracellular matrix (ECM). Equol at 0.3 or 1.2% in qPCR experiments using a human skin barrier model examined ECM gene expression. Equol, 5α-DHT, and 17β-estradiol at 10 nM were studied in human monolayer fibroblasts cultures (hMFC) for ECM protein expression. Human fibroblast three-dimensional organotypic cultures revealed equol's influence (@ 10 nM) on ECM proteins via fluorescent-activated cell sorting (FACS) analysis. In qPCR experiments, equol significantly increased collagen, elastin (ELN), and tissue inhibitor of metalloprotease and decreased metalloproteinases (MMPs) gene expression and caused significant positive changes in skin antioxidant and antiaging genes. In hMFC, equol significantly increased collagen type I (COL1A1), whereas, 5α-DHT significantly decreased cell viability that was blocked by equol. FACS analysis showed equol and 17β-estradiol significantly stimulated COL1A1, collagen type III (COL3A1), and ELN while MMPs were significantly decreased compared with control values. Finally, tamoxifen blocked the positive influences of equol on ECM proteins via FACS analysis. These findings suggest that equol has the potential to be used topically for the treatment and prevention of skin aging, by enhancing ECM components in human skin.

Sulfation of estradiol in human epidermal keratinocyte

Epidermis is one of the well-known estrogen target tissues. Information regarding estrogen metabolism in epidermis is still very limited compared to that of estrogen action. In the breast cancer tissue, 17β-estradiol (E(2)) is inactivated by sulfation and the expression level of estrogen sulfotransferase (SULT1E1) is inversely correlated with its malignancy. However, there is little datum about inactivation of estradiol in skin. In order to detect and measure E(2) and its metabolites simultaneously, we established an assay method with radio HPLC. A majority of [(3)H] labeled E(2) was converted to E(2) sulfate in normal human epidermal keratinocyte (NHEK) cells. The estimated activity of sulfotransferase toward E(2) at 20 nM was 0.11±0.01 (pmol/min/mg protein). Significant induction of estrogen sulfotransferase activity was observed in calcium-differentiated NHEK cells (0.58±0.07 (pmol/min/mg protein)). The gene expression of SULT1E1 was fifteen-fold higher in differentiated keratinocyte than in proliferating keratinocyte, whereas that of steroid sulfatase was reduced. These results suggest that E(2) inactivation is primarily mediated by SULT1E1 in keratinocyte and E(2) action is likely suppressed in epidermal differentiation.

Estrogens, estrogen receptors and melanoma

The skin is the largest nonreproductive target tissue on which estrogen plays many beneficial and protective roles. Although neither exogenous hormones nor pregnancy represent significant risk factors for melanoma, epidemiological data suggest a higher survival rate in women with metastatic disease versus men and in premenopausal versus postmenopausal patients. Despite the fact that hyperestrogenic signaling has long been implicated in the initiation and progression of several tumors, the role of estrogens in malignant melanoma is still unclear. The cellular effects of estrogens are mediated by two subtypes of estrogen receptors (ERs). Estrogen receptor β (ERβ), the predominant ER in the skin, antagonizes the proliferative action mediated by estrogen receptor α. According to recent immunohistochemical studies, ERβ protein expression decreases progressively with increased Breslow thickness and results in more invasive melanomas; thus, ERβ immunophenotype may distinguish melanomas linked to poor prognosis from those with a favorable course and lead to melanoma unresponsiveness to both estrogen and anti-estrogen treatment. Therefore, if future large-scale immunohistochemical and molecular studies point towards ERβ as an important factor in malignant melanoma progression, they will open up novel and targeted prognostic and therapeutic perspectives.

The role of estrogen-metabolizing enzymes and estrogen receptors in human epidermis

Local estrogen metabolism and its sensitivities in the skin have been also suggested to contribute to skin homeostasis in addition to age- and/or gender-dependent circulating estrogen, even though their local mechanisms have been largely unknown. To characterize their potential correlations, age- and gender-dependencies were evaluated focusing on 5 pivotal estrogen-metabolizing enzymes including aromatase, estrogen sulfotransferase, steroid sulfatase, and 17β-hydroxysteroid dehydrogenases and estrogen receptors (ERα and ERβ) using immunohistochemistry of 100 human skin specimens. When their epidermal expression levels were compared among 7 age groups, ranging from the teens to the seventies, the highest expression in the teens group and the lowest expression in the seventies group were found in the expression of aromatase and ERβ, respectively, while no significant differences between the male and the female groups were found in the immunoreactivities of our interested proteins. Our results suggest that age-related differences in aromatase and ERβ expressions impact epidermal homeostasis.

Iron sensitizes keratinocytes and fibroblasts to UVA-mediated matrix metalloproteinase-1 through TNF-α and ERK activation

Oestrogen deficiency is regarded as the main causative factor in postmenopausal skin ageing and photoageing. While women after menopause experience low levels of oestrogen because of cease of ovarian function, they are also exposed to high levels of iron as a result of cessation of menstruation. In this study, we investigated whether this increase in iron presents a risk to the postmenopausal skin. Because of the lack of appropriate animal models to closely mimic the low oestrogen and high iron conditions, we tested the hypothesis in a high iron and low oestrogen culture model. Here, we showed that primary human dermal fibroblasts exposed to iron did not affect the baseline levels of matrix metalloproteinase-1 (MMP-1) activity. However, the iron-exposed fibroblasts were sensitized to UVA exposure, which resulted in a synergistic increase in MMP-1. UVA activated the three members of MAPK family: ERKs, p38, and JNKs. Additional activation of ERKs by iron contributed to the synergistic increases. Primary normal human epidermal keratinocytes (NHEK) did not respond to iron or UVA exposure as measured by MMP-1, but produced tumor necrosis factor-alpha (TNF-α) in the media, which then stimulated MMP-1 in fibroblasts. Our results indicate that iron and UVA increase MMP-1 activity in dermal fibroblasts not only directly through ERK activation but also by an indirect paracrine loop through TNF-α released by NHEK. We conclude that in addition to oestrogen deficiency, increased iron as a result of menopause could be a novel risk factor by sensitizing postmenopausal skin to solar irradiation.

Role of genetics and sex steroid hormones in male androgenetic alopecia and female pattern hair loss: an update of what we now know

The role of genetic predisposition and the influence of sex steroid hormones are indisputable to the pathogenesis of male androgenetic alopecia (MAGA). The role of sex steroid hormones in female pattern hair loss (FPHL) is less known. A good knowledge of the pathophysiology underlying MAGA and FPHL empowers the clinician to confidently counsel patients and make informed therapeutic decisions. Vigorous research in recent years has provided greater insight into the role of genetics and sex steroids in physiological hair growth and cycling, as well as in hair follicle miniaturization, the histological hallmark of MAGA and FPHL. In the present review article directed towards clinicians, we discuss the current understanding of the role of androgens and oestrogens, as well as genetic associations with MAGA and FPHL. We also briefly discuss the interpretation of direct-to-consumer genetic testing for baldness to help clinicians understand the limitations of such tests.

Influence of season on some skin properties: winter vs. summer, as experienced by 354 Shanghaiese women of various ages

The facial skin of 354 women, aged 18-80, living in Shanghai, was investigated over two successive 6-month periods, summer and winter. Results from clinical assessments indicate that aging signs, such as wrinkling and sagging, are unaffected over such period. However, physical measurements revealed alterations in some functional criteria of the skin, such as sebum output, skin colour, melanin content of pigmented spots, skin hydration, all being increased during summer. The relationships between all criteria, as well as technical or applied inferences/consequences from this study, are discussed.

Ott's protein osmotic pressure of serum and interstitial fluid in chickens (Gallus gallus): effect of age and gender

Protein, or colloid, osmotic pressure (COP) is of sufficient magnitude to exert a powerful effect on Starling forces across the capillary wall. Although avian skin lacks active mechanisms for fluid transmission, such as sweating, it is now hypothesized that passive oncotic forces may regulate fluid flow and distribution in the skin and related phenomena. In this study, serum protein profiles, as well as COP in serum (COP(s)) and in suction blister fluid (COP(sbf)), were determined in juvenile, young and adult female and male chickens. For assessing COP, the Ott-Ahlqvist equation was applied. This equation can formulate the effects of multiple serum proteins on COP, according to their molecular mass. The COP values determined in chickens were lower than those previously found in mammals. COP(s) increased with age in males, and was higher in adult males than in adult females. In contrast, COP(sbf) decreased with age in females, although it was better preserved in adult males. The age-dependent decrease in COP was associated with a parallel decrease in the concentration of α(1)-globulin and albumin, and a positive correlation between packed cell volume (PCV) and COP was found. It is concluded that ageing affects Ott's COP around the vessel wall, and that an oncotic mechanism preserves plasma volume. The preservation of COP(sbf) in males suggests better maintenance of the interstitial ground substance. Females seem to lose more of a tissue's COP(s) counteracting force than males, probably as a result of gender-specific changes in the composition of the interstitial matrix. Further studies are required to elucidate the structure and function of avian lymphatics and their role in skin rheology.

Environmental and lifestyle factors associated with perceived facial age in Chinese women

Perceived facial age has been proposed as a biomarker of ageing with 'looking young for one's age' linked to physical and cognitive functioning and to increased survival for Caucasians. We have investigated the environmental and lifestyle factors associated with perceived facial ageing in Chinese women. Facial photographs were collected from 250 Chinese women, aged 25-70 years in Shanghai, China. Perceived facial age was determined and related to chronological age for each participant. Lifestyle and health information was collected by questionnaire. Bivariate analyses (controlling for chronological age) identified and quantified lifestyle variables associated with perceived facial age. Independent predictors of perceived age were identified by multivariate modelling. Factors which significantly associated with looking younger for one's chronological age included greater years of education (p<0.001), fewer household members (p=0.027), menopausal status (p=0.020), frequency of visiting one's doctor (p=0.013), working indoors (p<0.001), spending less time in the sun (p=0.015), moderate levels of physical activity (p=0.004), higher frequency of teeth cleaning (p<0.001) and more frequent use of facial care products: cleanser (p<0.001); moisturiser (p=0.016) or night cream (p=0.016). Overall, 36.5% of the variation in the difference between perceived and chronological age could be explained by a combination of chronological age and 6 independent lifestyle variables. We have thus identified and quantified a number of factors associated with younger appearance in Chinese women. Presentation of these factors in the context of facial appearance could provide significant motivation for the adoption of a range of healthy behaviours at the level of both individuals and populations.

Genistein aglycone improves skin repair in an incisional model of wound healing: a comparison with raloxifene and oestradiol in ovariectomized rats

BACKGROUND AND PURPOSE

Oestrogen loss at menopause is frequently related to poor wound healing. Genistein has been tested in anti-ageing cosmetic preparations with interesting results on skin health. Here, we investigated the effects of the genistein aglycones, given systemically, in an incisional model of wound healing, compared to systemic oestradiol and raloxifene.

EXPERIMENTAL APPROACH

Six months after ovariectomy (OVX), rats were randomly assigned to groups of 12 animals each and treated daily with genistein aglycone (1 and 10 mg kg(-1) s.c.), raloxifene hydrochloride (0.05 and 0.5 mg kg(-1) s.c.) or 17-alpha-ethinyl oestradiol (0.003 and 0.03 mg kg(-1) s.c.) for 12 weeks. Untreated OVX and sham OVX rats were used as controls. Then, 14 or 7 days before the end of the experiment, an incisional wound healing procedure was performed and skin specimens were collected to evaluate molecular, histological and functional measurements.

KEY RESULTS

Seven and fourteen days after wounding, samples from OVX rats showed a decrease in transforming growth factor-beta1, tissue transglutaminase 2 and vascular endothelial growth factor compared to samples from sham OVX rats. Oestradiol, raloxifene and genistein all significantly modified this decrease, but the lowest genistein dose exerted a greater effect than the other treatments. Moreover, the lowest dose of genistein was the most effective in improving skin healing and wound tensile strength.

CONCLUSIONS AND IMPLICATIONS

Genistein aglycone might be an alternative therapy for the management of skin wound healing.

Effect of long-term topical application of dehydroepiandrosterone (DHEA) and oral estrogens on morphology, cell proliferation, procollagen A1 and androgen receptor levels in rat skin

BACKGROUND

After cessation of estrogen secretion by the ovaries at menopause, all estrogens and almost all androgens acting in the skin of postmenopausal women are synthesized locally from dehydroepiandrosterone (DHEA), a prohormone of adrenal origin that progressively declines with age.

OBJECTIVE

To better understand the effects of DHEA on the skin, ovariectomized (OVX) rats were treated for 9 months with local topical application of DHEA compared with oral conjugated equine estrogens.

MATERIALS AND METHODS

Morphological evaluation, immunohistochemistry for androgen receptor (AR) and Cdc47 proliferation marker, and in situ hybridization for procollagen A1 were performed on dorsal skin.

RESULTS

Local topical DHEA application increased the thickness of the granular cell layer and total epidermis in OVX animals, whereas systemic estrogens had no significant effect. Although DHEA did not affect total dermal thickness, a 190% increase in dermal procollagen A1 mRNA was observed. Moreover, DHEA treatment decreased hypodermal thickness by 47% and increased skin muscle thickness by 58%. In the epidermis, DHEA induced a non-significant increase in cell proliferation, whereas AR labeling was increased in both the epidermis and dermis by DHEA.

CONCLUSIONS

Although estrogens did not significantly modify any of the above-mentioned parameters, the androgenic action of DHEA induced significant changes in all skin layers, without any sign of toxicity or lack of tolerance to DHEA after a 9-month local application of 4% (80 mg/kg) DHEA on the skin.

Aging well--the role of minimally invasive aesthetic dermatological procedures in women over 65

BACKGROUND

The western world is getting older. Aging well has become the new target of preventative medicine. Aesthetic dermatology can contribute to this quest. Females over 65 represent an important and growing group of consumers of cosmetic procedures. In this group, there is a paucity of scientific evaluation of aesthetic procedures.

OBJECTIVE

To review the use of minimally invasive procedures for facial rejuvenation in women over 65.

METHODS

Drawing from both the literature and personal experience, the opportunities, modifications, and limitations of minimally invasive techniques for facial rejuvenation in older women are considered.

RESULTS

In this older age group, dermal fillers, chemical and laser peels, and nonablative photorejuvenation remain useful and can each be used as stand-alone treatments. In this age group, botulinum toxin (BTX) injections are more often used in combination with other procedures.

CONCLUSIONS

With respect to aesthetic procedures, women over 65 are different from younger women. More scientific investigation is necessary to better meet needs of this growing part of the population. Available data suggest that aesthetic dermatology can make a major contribution to the complex matter of aging well.

Effect of selective estrogen receptor modulator/raloxifene analogue on proliferation and collagen metabolism of tendon fibroblast

The selective estrogen receptor modulator raloxifene is therapeutically beneficial for postmenopausal connective tissue degradation, such as osteoporosis, vascular sclerosis, and dermal degradation; however, the effects of raloxifene on postmenopausal tendon metabolism have not been clarified. In this study, we investigated the effects of raloxifene analogue (LY117018) on cell proliferation and collagen metabolism using cultured rat Achilles tendon fibroblasts. 17beta-Estradiol (E(2); 10(-11)-10(-9) M) and LY117018 (10(-9)-10(-7) M) had no significant effects on tendon fibroblast proliferation, based on a BrdU (5-bromo-2'-deoxyuridine) incorporation assay (24 hr) and a WST-8 colorimetric assay (2 or 6 days). Neither E(2) nor LY117018 significantly altered the expression of type I collagen, which is a main component of the tendon extracellular matrix (ECM), whereas both E(2) and LY117018 significantly increased the expression of matrix metalloproteinase (MMP)-13, which is responsible for tendon collagen degradation in rat. Also, both E(2) and LY117018 increased the expression of type III collagen and elastin, which are minor components of tendon ECM, but are considered to govern the elastic properties of tendons. These changes in collagen and MMP induced by either E(2) or LY117018 were attenuated by the estrogen receptor alpha blocker ICI 182,780. The results of this study suggest that postmenopausal estrogen deficiency might downregulate tendon collagen turnover and decrease tendon elasticity. Further, raloxifene treatment might restore these changes to premenopausal levels.

Estrogen deficiency and tobacco smoke exposure promote matrix metalloproteinase-13 activation in skin of aging B6 mice

Estrogen deficiency may contribute to extracellular matrix turnover in skin. This has led previous authors to postulate that aged skin heals less efficiently when compared to younger skin. Also, cigarette smokers have been shown to heal less efficiently than nonsmokers. Matrix metalloproteinase (MMP)-13, an enzyme that participates in the degradation of the extracellular matrix, has been implicated in physiologic aging and wound healing. This study investigates the effects of smoke exposure and estrogen deficiency on MMP-13 in young and aged female mouse skin. Young and aged female C57Bl/6J mice were ovariectomized. They were then randomly administered either 17beta-estradiol (E2) or placebo pellets. Half the animals in each age group were further randomized to exposure to cigarette smoke for a period of 6 months. Smoking and estrogen deficiency increased MMP-13 protein and activity in aged skin. The tissue inhibitors of metalloproteinases, which inhibit MMPs, activity was unchanged across all groups. E2 replacement decreased the actual level of MMP-13 protein and activity. We also found an increased collagen content and decreased ER receptor protein level in aged, smoke-exposed female mice. Our experimental data show that tobacco smoke exposure and estrogen deficiency are additive risk factors for promoting increased activity of MMP-13 in aged skin. These findings suggest that MMP-13 functions as a mediator of smoke-induced skin injury in susceptible, aged experimental female mice.

Delayed wound healing in elderly people

Our ability to heal wounds deteriorates with age, leading in many cases to a complete lack of repair and development of a chronic wound. Moreover, as the elderly population continues to grow the prevalence of non-healing chronic wounds is escalating. Cutaneous wound repair occurs through a combination of overlapping phases, including an initial inflammatory response, a proliferative phase and a final remodelling phase. In elderly subjects the inflammatory response is delayed, macrophage and fibroblast function compromised, angiogenesis reduced and re-epithelialization inhibited. Whilst a large body of historic research describes the defective processes that lead to delayed healing, only recently have the molecular mechanisms by which these defects arise begun to be elucidated. Current therapies available for treatment of chronic wounds in elderly people are surprisingly limited and generally ineffective. Thus there is an urgent need to develop new therapeutic strategies based on these recent molecular and cellular insights.