The biological actions of estrogens on skin

Spirodiclofen inhibited melanin synthesis in zebrafish embryos

Spirodiclofen has been registered and marketed in more than 50 countries worldwide and are widely used because of their broad-spectrum acaricidal activity and long-lasting efficacy. However, its environmental toxicological assessment to fish remains poorly understood. In the present study, zebrafish embryos were modelled and exposed to series concentration of spirodiclofen. It has been found that spirodiclofen exposure induced zebrafish embryos abnormal pigmentation, the quantitative analysis of melanin in images using Image J showed a significant decrease in the proportion of melanin area in zebrafish exposed to 0.146 mg/L treatment group at 48 and 96 h, respectively. ELISA analysis illustrated that zebrafish embryos exposed to 0.146 mg/L exhibited a significant decrease in the levels of melanin, tyrosinase and dopachrome tautomerase content, and in constant with these results, the genes involved in melanin synthesis (Tyr, Dct and Pck-β) were significantly downregulated, indicating that melanin synthesis was inhibited. The molecular docking showed that spirodiclofen had a lower binding energy with tyrosinase compared to other compounds. The results demonstrated that spirodiclofen interfered zebrafish embryos melanin synthesis. This provided new insights into the mechanism of spirodiclofen toxicity to zebrafish embryos.

Efficacy and safety of combined topical estradiol with minoxidil vs. topical minoxidil in female pattern hair loss: a trichoscopic randomized controlled trial

BACKGROUND

Female pattern hair loss (FPHL) is common and has a negative impact on quality of life. FPHL is more challenging to treat than male pattern hair loss, with minoxidil being the gold standard treatment. Several studies have used 17α-estradiol solution for treating FPHL with variable results, either alone or combined with minoxidil.

OBJECTIVES

To study the safety and efficacy of topical 17α-ethinylestradiol 0.01% combined with minoxidil 2% in comparison with minoxidil 2% in the treatment of FPHL.

METHODS

Forty-three women with FPHL were recruited to this randomized controlled study and were asked to blindly apply twice daily six puffs of a spray-on solution containing either 17α-ethinylestradiol 0.01% combined with minoxidil 2% (EMX group) or minoxidil 2% alone (MX group). Treatment continued for 6 months. Clinical and trichoscopic assessments were performed at baseline and at the end of the treatment.

RESULTS

At the end of the treatment period, both groups showed signs of improvement. Improvement parameters were better for the EMX group vs. the MX group, but this was not statistically significant. More patients in the EMX group experienced menstrual irregularities. Limitations include the limited number of patients and follow-up period. Also, the effects of estradiol were not studied on a cellular or molecular levels and systemic absorption of both medications was not determined.

CONCLUSIONS

The use of a 0.01% 17α-ethinylestradiol with a 2% minoxidil solution in the treatment of FPHL does not seem to offer a statistically significant advantage compared with minoxidil alone and may carry a higher risk of associated menstrual irregularities.

Skin cancer risk after hematopoietic stem cell transplantation: a systematic review and meta-analysis

Hematopoietic stem cell transplantation (HSCT) has improved outcomes for severe hematologic, malignant, and immune disorders, yet poses an increased risk of subsequent malignancies. This study aimed to examine the risk of skin cancer following HSCT and identify potential risk factors. The search was conducted in MEDLINE, EMBASE, and CINAHL databases until December 2023. Cohort studies reporting standardized incidence ratios (SIRs) for post-HSCT skin cancer or investigating risk factors were included. SIRs, or hazard ratios (HRs) with 95% confidence interval (CI), were calculated using random-effects inverse-variance models. Outcome endpoints were SIRs of skin cancer post-HSCT and risk factors, including gender, chronic graft-versus-host disease (cGVHD), voriconazole exposure, and total body irradiation (TBI). Twenty-six studies involving 164,944 HSCT recipients (allogeneic HSCT, n = 68,637; autologous HSCT, n = 95,435; mean age: 38.5 ± 13.8 years; 71,354 females [43.3%]) were analyzed. Overall, SIR for skin cancer post-HSCT was 7.21 (95% CI 3.98-13.08), with SIRs of 2.25 (95% CI: 1.37-3.68) for autologous HSCT, and 10.18 (95% CI 5.07-20.43) for allogeneic HSCT. Risk factors for skin cancer risk included cGVHD (HR = 2.86 [95% CI: 2.01-4.07]), specifically for basal cell and squamous cell carcinoma (SCC) (HR = 1.80 [95% CI: 1.31-2.46] and HR = 3.68 [95% CI: 2.39-5.68], respectively), male gender (HR = 1.56 [95% CI: 1.15-2.13]), especially for SCC (HR = 1.70 [95% CI: 1.03-2.80]), and voriconazole exposure (HR = 2.01 [95% CI: 1.12-3.61]). TBI showed no statistically significant association with subsequent skin cancer (HR = 1.12 [95% CI: 0.73-1.71]). These findings highlight the importance of rigorous skin cancer surveillance and preventive strategies in HSCT recipients, particularly in male individuals undergoing allogeneic transplants and those with identifiable risk factors, to enable early detection and intervention.

Causal relationship between sex hormones and cutaneous melanoma: a two-sample Mendelian randomized study

This study aimed to elucidate the genetic aspects of the relationship between sex hormones and cutaneous melanoma risk, providing valuable insights into this complex association. In this study, we used estradiol, bioavailable testosterone, sex hormone-binding globulin, and total testosterone as the exposure and melanoma as the outcome for two-sample Mendelian randomization analysis. In this study, a random-effects inverse-variance weighting (IVW) model was used as the main analysis model, and the corresponding weighted median, simple mode, weighted mode, and Mendelian randomization‒Egger methods were used as supplementary methods. We assessed both heterogeneity and horizontal pleiotropy in our study, scrutinizing whether the analysis results were affected by any individual single nucleotide polymorphism. The random-effects IVW method indicated that estradiol [odds ratio (OR), 1.000; 95% confidence interval (CI), 0.998-1.003; P  = 0.658], bioavailable testosterone (OR = 1.001, 95% CI, 0.999-1.003; P  = 0.294), sex hormone-binding globulin (IVW: OR, 1.000; 95% CI, 0.998-1.003; P  = 0.658), and total testosterone (IVW: OR, 1.002; 95% CI, 0.999-1.005; P  = 0.135) were not genetically linked to cutaneous melanoma. No analyses exhibited heterogeneity, horizontal pleiotropy, or deviations. We were unable to find genetic evidence for a causal relationship between sex hormones and the occurrence of cutaneous melanoma in this study. These results are limited by sample size and population, so the causal relationship between sex hormones and cutaneous melanoma needs to be further studied.

'Speed-ageing' of human skin in serum-free organ culture ex vivo: An instructive novel assay for preclinical human skin ageing research demonstrates senolytic effects of caffeine and 2,5-dimethylpyrazine

Preclinical human skin ageing research has been limited by the paucity of instructive and clinically relevant models. In this pilot study, we report that healthy human skin of different age groups undergoes extremely accelerated ageing within only 3 days, if organ-cultured in a defined serum-free medium. Quantitative (immuno-)histomorphometry documented this unexpected ex vivo phenotype on the basis of ageing-associated biomarkers: the epidermis showed significantly reduced rete ridges and keratinocyte proliferation, sirtuin-1, MTCO1 and collagen 17a1 protein levels; this contrasted with significantly increased expression of the DNA-damage marker, γH2A.X. In the dermis, collagen 1 and 3 and hyaluronic acid content were significantly reduced compared to Day 0 skin. qRT-PCR of whole skin RNA extracts also showed up-regulated mRNA levels of several (inflamm-) ageing biomarkers (MMP-1, -2, -3, -9; IL6, IL8, CXCL10 and CDKN1). Caffeine, a methylxanthine with recognized anti-ageing properties, counteracted the dermal collagen 1 and 3 reduction, the epidermal accumulation of γH2A.X, and the up-regulation of CXCL10, IL6, IL8, MMP2 and CDKN1. Finally, we present novel anti-ageing effects of topical 2,5-dimethylpyrazine, a natural pheromone TRPM5 ion channel activator. Thus, this instructive, clinically relevant "speed-ageing" assay provides a simple, but powerful new research tool for dissecting skin ageing and rejuvenation, and is well-suited to identify novel anti-ageing actives directly in the human target organ.

Secondary glaucoma: Toward interventions based on molecular underpinnings

Glaucoma is a heterogeneous group of progressive diseases that leads to irreversible blindness. Secondary glaucoma refers to glaucoma caused by a known underlying condition. Pseudoexfoliation and pigment dispersion syndromes are common causes of secondary glaucoma. Their respective deposits may obstruct the trabecular meshwork, leading to aqueous humor outflow resistance, ocular hypertension, and optic neuropathy. There are no disease-specific interventions available for either. Pseudoexfoliation syndrome is characterized by fibrillar deposits (pseudoexfoliative material) on anterior segment structures. Over a decade of multiomics analyses taken together with the current knowledge on pseudoexfoliative glaucoma warrant a re-think of mechanistic possibilities. We propose that the presence of nucleation centers (e.g., vitamin D binding protein), crosslinking enzymes (e.g., transglutaminase 2), aberrant extracellular matrix, flawed endocytosis, and abnormal aqueous-blood barrier contribute to the formation of proteolytically resistant pseudoexfoliative material. Pigment dispersion syndrome is characterized by abnormal iridolenticular contact that disrupts iris pigment epithelium and liberates melanin granules. Iris melanogenesis is aberrant in this condition. Cytotoxic melanogenesis intermediates leak out of melanosomes and cause iris melanocyte and pigment epithelium cell death. Targeting melanogenesis can likely decrease the risk of pigmentary glaucoma. Skin and melanoma research provides insights into potential therapeutics. We propose that specific prostanoid agonists and fenofibrates may reduce melanogenesis by inhibiting cholesterol internalization and de novo synthesis. Additionally, melatonin is a potent melanogenesis suppressor, antioxidant, and hypotensive agent, rendering it a valuable agent for pigmentary glaucoma. In pseudoexfoliative glaucoma, where environmental insults drive pseudoexfoliative material formation, melatonin's antioxidant and hypotensive properties may offer adjunct therapeutic benefits. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

Single-cell analysis of human dermal fibroblasts isolated from a single male donor over 35 years

The aim of this study is to examine the effects of ageing on dermal fibroblast heterogeneity based on samples obtained from the same donor. We used a dermal fibroblast lineage (named ASF-4 cell lines) isolated from the inner side of the upper arm of a healthy male donor over a 35-year period, beginning at 36 years of age. Because clonal analysis of ASF-4 cell lines demonstrated a donor age-dependent loss of proliferative capacity and acquisition of senescent traits at the single-cell level, cultured cells frozen at passage 10 at ages 36 and 72 years were subjected to single-cell RNA sequencing. Transcriptome analysis revealed an increase in senescent fibroblasts and downregulation of genes associated with extracellular matrix remodelling with ageing. In addition, two putative differentiation pathways, with one endpoint consisting of senescent fibroblasts and the other without, were speculated using a pseudo-time analysis. Knockdown of the characteristic gene of the non-senescent fibroblast cluster endpoint, EFEMP2, accelerated cellular senescence. This was also confirmed in two other normal human dermal fibroblast cell lines. The detection of a common cellular senescence-related gene from single-donor analysis is notable. This study provides new insights into the behaviour of dermal fibroblasts during skin ageing.

Acne accounts for an almost 2.5-fold higher proportion of dermatology visits among adult females compared to adult males in the United States: A study of the national ambulatory medical care survey from 2002-2016

BACKGROUND

Acne vulgaris affects a significant number of females into adulthood. Juvenile acne and adult acne have different presentations and potentially distinctive pathogeneses. However, patterns in treatments specifically related to the adult female population have previously not been studied.

METHODS

Retrospective database analysis of healthcare utilization and medications prescribed for acne using the National Ambulatory Medical Care Survey (NAMCS) data from 2002-2016 was performed.

RESULTS

After age 20, acne accounted for an almost 2.5-fold higher proportion of dermatology visits among females compared to males (10.1% vs. 4.1%, P < 0.001). Tetracycline-class antibiotics were the most prescribed therapy within all age groups of females between 2002-2016. However, there was also a substantial rise in prescriptions of spironolactone beginning in 2012.

CONCLUSION

A significantly greater proportion of dermatology visits by adult females are for acne in comparison to adult males. Tetracycline-class antibiotics remain the most prescribed therapy in adult age groups despite a potentially different pathogenesis of adult acne. Therefore, there is a need for further studies comparing the effectiveness of therapies specifically for adult female acne.

Skin cancer risk of menopausal hormone therapy in a Korean cohort

Conflicting studies exist on the association between menopausal hormone therapy (MHT) and skin cancers, such as melanoma and non-melanoma skin cancer (NMSC). This retrospective cohort study aimed to evaluate the risk of skin cancer from MHT using data from 2002 to 2019 from the National Health Insurance Service in South Korea. We included 192,202 patients with MHT and 494,343 healthy controls. Women > 40 years who had menopause between 2002 and 2011 were included. Patients with MHT had at least one MHT for at least 6 months and healthy controls had never been prescribed MHT agents. We measured the incidence of melanoma and NMSC. Melanoma developed in 70 (0.03%) patients with MHT and 249 (0.05%) controls, while the incidence of NMSC was 417 (0.22%) in the MHT group and 1680 (0.34%) in the controls. Tibolone (hazard ratio [HR] 0.812, 95% confidence interval [CI] 0.694-0.949) and combined oestrogen plus progestin by the manufacturer (COPM; HR 0.777, 95% CI 0.63-0.962) lowered the risk of NMSC, while other hormone groups did not change the risk. Overall, MHT was not associated with melanoma incidence in menopausal Korean women. Instead, tibolone and COPM were associated with a decrease in NMSC occurrence.

Mastocytosis and Skin Cancer: The Current State of Knowledge

Mastocytosis is a heterogeneous group of diseases associated with excessive proliferation and accumulation of mast cells in different organs. Recent studies have demonstrated that patients suffering from mastocytosis face an increased risk of melanoma and non-melanoma skin cancer. The cause of this has not yet been clearly identified. In the literature, the potential influence of several factors has been suggested, including genetic background, the role of cytokines produced by mast cells, iatrogenic and hormonal factors. The article summarizes the current state of knowledge regarding the epidemiology, pathogenesis, diagnosis, and management of skin neoplasia in mastocytosis patients.

Clinical and metagenomic profiling of hormonal acne-prone skin in different populations

INTRODUCTION

Acne is one of the most common skin concerns of unknown etiology, often connected to the menstrual cycle in women, and possibly to the microbial profile and function.

OBJECTIVE

We aimed to investigate how hormonal fluctuation affects hormonal acne-prone skin in different populations in relation to skin clinical parameters and microbial profiles.

METHODS

We evaluated skin features by using biophysical and topographical tools. For microbial profiling, we sequenced facial skin microbiota and associated the findings with the skin clinical parameters during the different phases of the menstrual cycle.

RESULTS

We identified differences between and within hormonal phases in women of Chinese and Caucasian origin. Changes were discovered in transepidermal water loss (TEWL), sebum level, hydration level, and pore volume. The most abundant identifiable genera in both ethnicities were Cutibacterium, Staphylococcus, and Streptococcus, without any significant abundant differences within the menstrual cycle. Interestingly, 11 bacterial metabolic pathways were downregulated in Chinese compared to Caucasian skin during the follicular phase. The majority of these pathways were associated with skin redox balance, perhaps indicating a weaker oxidative stress response in Chinese versus Caucasian skin. Novosphingobium taxa were increased in the Chinese skin microbiome, which has been reported to protect skin from pollution-mediated oxidative stress.

CONCLUSION

Thus, this pilot study explored some of the clinical and metagenomic changes in acne-prone skin, and provide guidance to tailor-personalized skin care regimes during the menstrual cycle. Also, the skin redox status in acne-prone skin, provides more opportunity to tailor-personalized skin care regimes.

Real sweating in a virtual stress environment: Investigation of the stress reactivity in people with primary focal hyperhidrosis

Background

Hyperhidrosis (excessive sweating, OMIM %114110) is a complex disorder with multifactorial causes. Emotional strains and social stress increase symptoms and lead to a vicious circle. Previously, we showed significantly higher depression scores, and normal cortisol awakening responses in patients with primary focal hyperhidrosis (PFH). Stress reactivity in response to a (virtual) Trier Social Stress Test (TSST-VR) has not been studied so far. Therefore, we measured sweat secretion, salivary cortisol and alpha amylase (sAA) concentrations, and subjective stress ratings in affected and non-affected subjects in response to a TSST-VR.

Method

In this pilot study, we conducted TSST-VRs and performed general linear models with repeated measurements for salivary cortisol and sAA levels, heart rate, axillary sweat and subjective stress ratings for two groups (diagnosed PFH (n = 11), healthy controls (n = 16)).

Results

PFH patients showed significantly heightened sweat secretion over time compared to controls (p = 0.006), with highest quantities during the TSST-VR. In both groups, sweating (p < 0.001), maximum cortisol levels (p = 0.002), feelings of stress (p < 0.001), and heart rate (p < 0.001) but not sAA (p = 0.068) increased significantly in response to the TSST-VR. However, no differences were detected in subjective ratings, cortisol concentrations and heart rate between PFH patients and controls (p_all > 0.131).

Conclusion

Patients with diagnosed PFH showed stress-induced higher sweat secretion compared to healthy controls but did not differ in the stress reactivity with regard to endocrine or subjective markers. This pilot study is in need of replication to elucidate the role of the sympathetic nervous system as a potential pathway involved in the stress-induced emotional sweating of PFH patients.

Update on Melasma-Part I: Pathogenesis

Melasma is a multifactorial dyschromia that results from exposure to external factors (such as solar radiation) and hormonal factors (such as sex hormones and pregnancy), as well as skin inflammation (such as contact dermatitis and esthetic procedures), in genetically predisposed individuals. Beyond hyperfunctional melanocytes, skin with melasma exhibits a series of structural and functional alterations in the epidermis, basement membrane, and upper dermis that interact to elicit and sustain a focal hypermelanogenic phenotype. Evolution in the knowledge of the genetic basis of melasma and the cutaneous response to solar radiation, as well as the roles of endocrine factors, antioxidant system, endothelium proliferation, fibroblast senescence, mast cell degranulation, autophagy deficits of the melanocyte, and the paracrine regulation of melanogenesis, will lead to the development of new treatments and preventive strategies. This review presents current knowledge on these aspects of the pathogenesis of melasma and discusses the effects of specific treatments and future research on these issues.

Effect of estrogen in malignant melanoma

BACKGROUND

Melanoma is associated with poor prognosis in its advanced stages. Potential influence of estrogen and its metabolites on melanoma growth has been suggested.

AIMS

The objective of this review was to provide an overview on the evidence related to estrogen in malignant melanoma.

MATERIALS AND METHODS

Literature search using PubMed, Google Scholar and relevant cross-references of the retrieved articles was performed to review relevant published articles related to estrogen and its effects in malignant melanoma.

RESULTS

Effect of estrogen signaling on a tissue largely depends on the relative expression of estrogen receptors (ER) α and β. Gender differences in melanoma may be explained by the difference in expression of these receptors. ERβ is the principal ER in melanoma.

DISCUSSION

Although there is uncertainty about role of estrogen in pathogenensis and progression of melanoma, evidence suggests that its growth and metastasis are influenced by estrogen stimulation. Role ER on the proliferation of melanoma cells is well described.

CONCLUSION

There is a need of safe and effective therapy for melanoma, especially for advanced cases. After the establishment of specific role of estrogen and its receptor, analysis of specific genetic mutation can be performed for proper utilization of targeted therapies.

Beneficial Effects of Young Coconut Juice on Increasing Skin Thickness, Enhancing Skin Whitening, and Reducing Skin Wrinkles in Ovariectomized Rats

It has been previously demonstrated in light microscopic and immunohistochemical studies that ovariectomized rats receiving young coconut juice at 100 mL/kg BW showed much better wound healing and improved skin complexion. Nevertheless, it was found that young coconut juice at 100 mL/kg BW/day caused unfavorable side effects, such as glycogen deposition in the liver. Therefore, in the current study, 3 lower doses (10, 20, and 40 mL/kg BW/day) were optimized, and the ultrastructure was further investigated. Compared to normal rats, all the parameters regarding skin changes, including epidermal and dermal thickness, the number of hair follicles, the diameters of collagen fibrils, perimeters, and nuclei of fibroblast and keratinocyte cells, and ultrastructural changes in keratinocyte and fibroblast cells were significantly reduced in ovariectomized rats. Those parameters in the ovariectomized rats were restored to normal by injecting estradiol benzoate or by feeding young coconut juice to the rats, where the effect was found to be dose-related but not in the case of all the parameters. In most cases, a dose of young coconut juiceof 40 mL/kg BW/day was the optimal dose. The results suggest that young coconut juice may be as effective as estradiol benzoate in reducing skin atrophy/aging, probably as a selective estrogen receptor moderator.

Estrogens and phytoestrogens in body functions

Estrogens are the hormones of reproduction in women as well as of many other important functions in the male and female body. They undergo significant changes in the different phases of life, e.g. during puberty, pregnancy or at menopause/andropause. Phytoestrogens are natural non-steroidal phenolic plant compounds that can mimic the activity of estrogens and their beneficial effects in women and in men. This narrative review summarizes the literature on the physiological role of estrogens and the several potential health benefits of phytoestrogens, with particular attention given to the possible role of phytoestrogens in aging.

Epicutaneous Administration of 17β-Estradiol Induces Langerhans Cells Depletion

BACKGROUND

Langerhans cells (LC) number and function in mouse vaginal mucosa are affected by 17β-estradiol (E₂) application; nonetheless, its effect on epidermal LC has not been studied. The purpose of this study was to evaluate the effect of topical administration of E₂ on the number, phenotype, and migratory ability of LC in mouse skin.

METHODS

Ears of adult CD1 male mice were topically treated once with several doses. Immunohistochemical staining for CD207 and TUNEL staining were performed. LC migration to lymph nodes and the effect on the expression of costimulatory molecules on cultured dendritic cells (DC) were also evaluated.

RESULTS

E₂ decreased the number of CD207+ LC in a dose-dependent manner. One hour after treatment, 1 and 10 µg/mL E₂ significantly reduced the LC number by 21% and 26%, respectively, after two hours, the reduction was 23% and 41%, respectively. After 48 hours, LC recovered, and after 96 hours of treatment, the CD207+/MHCII+ DC numbers were increased in regional lymph nodes. However, CD86 and CD40 molecules were expressed at lower levels than in positive control. The TUNEL assay did not show apoptotic cells. Furthermore, in cultured DC, E₂ promoted a decrease in CD40 and CD86 expression and an increase in CD273, CD274, MHCII, and CCR7.

CONCLUSIONS

The topical administration of E₂ induced a transitory local diminution of LC population and a tolerogenic phenotype. This decrease in epidermal LC suggests that E₂ may affect skin immune responses, inducing an inhibitory response, which should be considered when prescribing topical E₂ medications.

Differential diagnosis and management of hyperpigmentation

There is an increasing recognition of ethnic dermatology to reflect the increase in skin of colour (SOC) populations in the UK. Hyperpigmentary disorder is one of the commonest skin concerns in SOC but there has been limited training available in this field of dermatology. Variations in skin colour are genetically determined by the amount of melanin content, the eumelanin/pheomelanin ratio and the size of melanosomes, but is also influenced by other factors such as hormones and extrinsic factors such as ultraviolet radiation. Hyperpigmentation is a broad term to describe increased pigmentation in the skin, and making a correct diagnosis is an important first step in the successful management of hyperpigmentary disorders. A systematic approach based on the disease pathogenesis (e.g. reactive vs. nonreactive, increased melanin vs. increased number of cells or epidermal vs. dermal pigmentation) aided by a detailed history and clinical examination is the best way to diagnose a hyperpigmentary disorder. Based on its pathogenesis, management can be planned. For epidermal hyperpigmentation caused by increased melanin, topical skin-lightening agents targeting inhibition of tyrosinase or melanosome transfer and promotion of keratinocyte turnover can be used. Hydroquinone-containing cream is the gold-standard treatment for epidermal hyperpigmentation. Alternative treatments include laser toning or chemical peels. However, increased dermal pigmentation is more challenging to target with topical treatments. If hyperpigmentation is due to increased numbers of melanocytes or keratinocytes, high-fluence laser is the most appropriate treatment method.

Ultraviolet Radiation and Chronic Inflammation-Molecules and Mechanisms Involved in Skin Carcinogenesis: A Narrative Review

The process of skin carcinogenesis is still not fully understood. Both experimental and epidemiological evidence indicate that chronic inflammation is one of the hallmarks of microenvironmental-agent-mediated skin cancers and contributes to its development. Maintaining an inflammatory microenvironment is a condition leading to tumor formation. Multiple studies focus on the molecular pathways activating tumorigenesis by inflammation and indicate several biomarkers and factors that can improve diagnostic and prognostic processes in oncology and dermatology. Reactive oxygen species produced by ultraviolet radiation, oxidizers, or metabolic processes can damage cells and initiate pro-inflammatory cascades. Considering the potential role of inflammation in cancer development and metastasis, the identification of early mechanisms involved in carcinogenesis is crucial for clinical practice and scientific research. Moreover, it could lead to the progress of advanced skin cancer therapies. We focus on a comprehensive analysis of available evidence and on understanding how chronic inflammation and ultraviolet radiation can result in skin carcinogenesis. We present the inflammatory environment as complex molecular networks triggering tumorigenesis and constituting therapeutic targets.

Lipidomic analysis of facial skin surface lipid reveals the causes of pregnancy-related skin barrier weakness

Self-reported skin discomfort is a common problem during pregnancy, but it is not clear whether skin barrier function is altered in the process. Few studies have described the skin barrier function during pregnancy. In this work, we used highly sensitive and high-resolution ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) to distinguish skin surface lipid (SSL) combined with multivariate analysis of lipids and metabolic changes to determine the relationship between SSL changes and skin physiology during pregnancy in order to better understand the skin condition of pregnant women. The results showed a significant reduction in the total lipid content in pregnant women. A total of 2270 lipids were detected, and the relative abundances of fatty acyls and glycerolipids were significantly reduced, while glycerophospholipids (GPs), sphingolipids, and saccharolipids was significantly increased in the pregnancy group. Multivariate data analysis indicated that 23 entities constituted the most important individual species responsible for the discrimination and phosphatidylcholine was the most abundant lipid in pregnancy group. In addition, compared to SSL profile of control group, it was observed that the average chain length of ceramides and fatty acids both decreased in SSL profile of pregnancy group. The main and most commonly affected pathway was that of GP pathways. These findings indicate that skin lipids are significantly altered in mid-pregnancy compared to the control group. Changes in ostrogen during pregnancy also make the skin more susceptible to inflammatory factors and lead to more fragile and susceptible skin, weakening the skin barrier along with the lipid alterations.

Gender differences in UV-induced skin inflammation, skin carcinogenesis and systemic damage

Ultraviolet (UV) radiation-induced chronic inflammation contributes to all stages of skin tumor development. In addition, gender plays an important role in inflammatory diseases or cancer. In this study, histopathology changes, hematology, oxidative stress and inflammatory response were used to evaluate sex differences in UV-induced chronic inflammation-associated cancer development. The results showed that the male and female mice had photoaging damage at the 9th week. However, skin tumors only appeared in male mice at 31st week. Furthermore, UV increased ROS production, p65, p-p65, IL-6 and TNF-α protein expressions in skin, and these factors elevated more in male mouse model. Hematology results showed that the parameters of blood systemic inflammation were changed in different degrees in model groups, while the pathological results showed inflammatory cell infiltration in the internal organs of both model groups in varying degrees. These results indicate that there are gender differences in UV-induced skin inflammation, carcinogenesis and systemic damage. Moreover, male mice are more sensitive to UV irradiation, which may be responsible to greater oxidative stress and inflammatory damage.

Age-Related Changes in Female Scalp Dermal Sheath and Dermal Fibroblasts: How the Hair Follicle Environment Impacts Hair Aging

In women, aging leads to reduced hair density and thinner fibers and can result in female-pattern hair loss. However, the impact of the aging dermal environment on female scalp hair follicles remains unclear. In this study, we document in situ changes in 22 women (aged 19-81 years) and primary cultures of dermal fibroblast and dermal sheath cells. In situ, the papillary reticular boundary was indistinguishable in the young scalp but prominent in the scalp of those aged >40 years, accompanied by reduced podoplanin (PDPN) expression, increased versican expression, and changes in collagen organization. Hair follicles were shorter, not reaching the adipose layer. Hyaluronic acid synthase 2 was highly expressed, whereas matrix metalloproteinase 1 was elevated in the dermal papilla and dermal sheath in situ. Primary dermal fibroblast cultures confirmed that matrix metalloproteinase 1 mRNA, MMP1, increased with aging, whereas in dermal sheath cells, hyaluronic acid synthase 2, HAS2, and PDPN increased and α-smooth muscle actin αSMA mRNA decreased. Both exhibited increased cartilage oligomeric protein, COMP mRNA expression. Proteomics revealed an increase in dermal sheath proteins in the dermal fibroblast secretome with aging. In summary, aging female scalp shows striking structural and biological changes in the hair follicle environment that may impact hair growth.

Paracrine roles of hormone receptors in Riehl's melanosis: A quantitative analysis of oestrogen and progesterone receptor expression patterns

The incidence of Riehl's melanosis (RM) is most common in the fifth or sixth decade of life with a female preponderance. As the skin is regarded a non-reproductive organ on which sex steroid hormones act, a possible relationship between the pathogenesis of RM and sex steroid hormone receptors can be inferred. This study intended to evaluate the expression profile of oestrogen receptor (ER)β and progesterone receptor (PR) in RM. Twelve lesional and perilesional normal-appearing skin samples of RM patients and the skin of 12 healthy controls were retrieved for the analysis. Real-time PCR analysis and immunohistochemical studies were conducted for ERβ and PR, respectively. The lesional and perilesional normal-appearing skin of 12 patients with RM and the skin of 12 healthy controls were retrieved for the analysis. Interestingly, the dermal ERβ immunostaining intensity was increased more in lesional skin than in perilesional skin. When compared to healthy controls, increased expression of ERβ and PR mRNAs was observed in the lesional skin of patients with RM. Of note, epidermal and dermal ERβ and dermal PR expressions showed increased staining intensities in the lesional skin of RM patients compared with healthy controls. The altered expression of ERβ and PR in RM supports the possible role of these hormone receptors in the pathogenesis of RM.

Morphological and Functional Changes in Skin of Adult Male Rats Chronically Treated with Letrozole, a Nonsteroidal Inhibitor of Cytochrome P450 Aromatase

Skin is a target for hormones and a site of hormone production. Aromatase inhibitors such as letrozole reduce circulating estrogen. The aim of the study was to investigate the morphology of the dermis and immunoexpression of androgen receptor (AR), estrogen receptor α and β (ERα, ERβ), luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), and cytochrome P450 aromatase (P450arom) in male rats with a deficit of estradiol. Experiments were performed on skin of 12 male rats. Rats in the experimental group received per os letrozole for 6 months. For morphological analysis, van Gieson, Sirius Red and orcein staining of sections was performed. In immunohistochemistry, reactions with specific antibodies (anti-P450arom, LHR, FSHR, ERα, ERβ) were used. In morphometric analysis, sections were stained with hematoxylin and eosin. Differences between groups were assessed by Mann-Whitney U-test. There were no differences in the diameter of collagen fibers. The dermis of letrozole-treated animals showed areas without collagen fibers, and expression of P450arom, ERα and ERβ was diminished in the skin of these animals. This study indicates that estrogens exert an effect via ERs that has a role in maintaining proper skin morphology in males, together with androgen. This is also the first documented expression of FSHR in the skin of male rats.

Analysis of Tumour Related Data and Clinical Features of Eyelid Carcinomas

Almost 10% of worldwide skin cancers are located at the eyelid level. In European countries, malign eyelid tumours are mostly represented by basal and squamous cell carcinomas, and usually affect elderly patients. In order to study the clinical features of eyelid tumours, and potential correlations between tumour parameters, we have enrolled a cohort of 98 subjects from a south-western region of Romania. Our study confirmed the majority of results from other European studies, as basal cell carcinoma was the most frequent malign form, being diagnosed for more than 85% of patients with declared prolonged sun exposure; tumours were mostly located on the superior eyelid, especially for males, and may present slow progression rates. We have identified significant correlations only between the tumour stage and symptoms' duration, and also between the tumour stage and smoking habit, for females.

Mechanistic Models of Signaling Pathways Reveal the Drug Action Mechanisms behind Gender-Specific Gene Expression for Cancer Treatments

Despite the existence of differences in gene expression across numerous genes between males and females having been known for a long time, these have been mostly ignored in many studies, including drug development and its therapeutic use. In fact, the consequences of such differences over the disease mechanisms or the drug action mechanisms are completely unknown. Here we applied mechanistic mathematical models of signaling activity to reveal the ultimate functional consequences that gender-specific gene expression activities have over cell functionality and fate. Moreover, we also used the mechanistic modeling framework to simulate the drug interventions and unravel how drug action mechanisms are affected by gender-specific differential gene expression. Interestingly, some cancers have many biological processes significantly affected by these gender-specific differences (e.g., bladder or head and neck carcinomas), while others (e.g., glioblastoma or rectum cancer) are almost insensitive to them. We found that many of these gender-specific differences affect cancer-specific pathways or in physiological signaling pathways, also involved in cancer origin and development. Finally, mechanistic models have the potential to be used for finding alternative therapeutic interventions on the pathways targeted by the drug, which lead to similar results compensating the downstream consequences of gender-specific differences in gene expression.

DHT and E2 synthesis-related proteins and receptors expression in male yak skin during different hair follicle stages

Dihydrotestosterone (DHT) and 17β-estradiol (E2) are sex hormones that regulate human hair follicle (HF) growth and are produced by peripheral reduction and aromatization of testosterone. However, the expression patterns of DHT and E2 synthesis-related proteins and their receptors in male yak skin during different HF stages (telogen, anagen, and catagen) are unknown. In this study, we found that both 5α-red and androgen receptor (AR) were expressed in epithelial cells and AR was expressed in the dermal papilla. Additionally, the transcription level of 5α-red1 at different HF stages was significantly higher than that of 5α-red2 mRNA at the same stage; 5α-red1 and 5α-red2 proteins peaked during the anagen and telogen periods of HF, respectively. However, AR protein was only expressed in the skin during the anagen phase of HF. Aromatase and estrogen receptors (ERα and ERβ) were expressed in cutaneous epithelial cells, whereas ERα and ERβ were expressed in the dermal papilla; the transcription level of ERα in HFs at each stage was much higher than that of ERβ. From the catagen to telogen phase, aromatase protein expression was down-regulated, while ERα protein expression was up-regulated. Based on our results, we speculate that 5α-red1 is essential for the synthesis of DHT in male yak skin epithelial cells and promotes the growth of HFs through AR. E2 synthesized by male yak skin epithelial cells may inhibit the growth of male yak skin HFs by ERα. These results provide a foundation for further study on the mechanism of hormone-regulated male yak skin HFs.

Recent advances in the anti-aging effects of phytoestrogens on collagen, water content, and oxidative stress

Skin undergoes degenerative changes as it ages, which include the loss of elasticity, reductions in the epidermal thickness and collagen content, elastic fiber degeneration, and increased wrinkling and dryness. Skin aging can be significantly delayed by the administration of estrogen. Estrogen deficiency following menopause results in atrophic skin changes and the acceleration of skin aging. Estrogen administration has positive effects on human skin by delaying or preventing skin aging manifestations, but the use of estrogen replacement is a risk factor for breast and uterine cancer. Phytoestrogens are a large family of plant‐derived molecules possessing various degrees of estrogen‐like activity; they exhibit agonist or antagonist estrogenic properties depending on the tissue. These molecules could be ideal candidates to combat skin aging and other detrimental effects of hypoestrogenism. In this paper, we review the effects of phytoestrogens on human skin and the mechanisms by which phytoestrogens can alleviate the changes due to aging.

Contributions by MC1R Variants to Melanoma Risk in Males and Females

Importance

Recently, the red hair variants of MC1R were found to contribute differently to pigmentation phenotype in males and females.

Objective

To investigate the role of these variants in melanoma risk in males and females separately because carriers of the red hair variants of MC1R are at increased risk of melanoma.

Design, Setting, and Participants

In this hospital-based, case-control study, we evaluated the effect of MC1R and melanoma risk for males and females separately by performing multivariate logistic regression analyses.

Main Outcomes and Measures

Association of MC1R variants and melanoma risk in males and females.

Results

A total of 905 females (473 melanoma cases, 432 controls) and 886 males (518 melanoma cases, 368 controls) were included in the analyses. The mean (SD) age of the study population was 59.2 (15.6). In females, carrying any MC1R red hair variants remained an independent risk factor of melanoma in a multivariable analysis (adjusted odds ratio [OR], 2.19 [95% CI, 1.60-2.99]), whereas in males, only signs of actinic skin damage (lentigines on the back [OR, 2.56; 95% CI, 1.47-4.45; P = .001] and the hands [OR, 2.31; 95% CI, 1.24-4.29; P = .008] and wrinkling on the neck [OR, 2.17; 95% CI, 1.23-3.82; P = .007]) and sunburns (OR, 1.65; 95% CI, 1.12-2.42; P = .01) remained significant risk factors.

Conclusions and Relevance

MC1R variants contribute differently to melanoma risk in males and females. This could be helpful to better classify melanoma risk factors between the sexes.

Can aging be slowed down?

Aging is a complex process, with genetic and environmental influences, that unfolds over time. The rate at which skin aging proceeds is predictable, although many persons appear older or younger than their chronologic age. This is especially evident in rare genetic disorders such as Hutchinson-Gilford progeria syndrome in which persons suffer from a premature aged appearance and in neotenic complex syndrome in which children appear to be "frozen in time," remaining physically and cognitively similar to an infant or toddler despite increasing age. Ideally, it would be desirable to slow down the aging process with the hope of looking younger longer and improving good health and longevity. Evidence that this is possible comes from data showing increases in average human life expectancy over the past century and recognition of the photoaging effects of sun exposure, with the development of protective strategies, including the routine use of clothing, hats, sunglasses, and sunscreen while avoiding the sun during its peak hours of 10 am to 4 pm. Other strategies for maintaining younger-looking skin include the adoption of a healthy lifestyle and use of antiaging skin preparations. Stem cell therapy may also play a role in aging therapy. Current research is clarifying the genetic basis of skin youthfulness and may help to direct future therapies to target key biologic pathways of aging.

Analysis of the Effect of Serum Estradiol Concentration on Facial Skin Moisture, Pore Width, Discoloration and Smoothness in 16- to 50-Year-Old Women at the 5th and 25th Days of the Menstrual Cycle

BACKGROUND/AIMS

Analysis of the relationship between the estradiol blood concentration and the skin moisture, pore width, discoloration and smoothness in differently aged women on the 5th and 25th days of the menstrual cycle.

METHODS

The study involved 57 women divided into 4 age groups. Measurements of skin moisture, pore width, discoloration and smoothness were performed using the Aramo SG Aram Huvis device. The estradiol serum concentration was determined by radioimmunoassay.

RESULTS

In the luteal phase of the cycle, facial skin moisture increases from 93.5% of the correct standard moisture index in the youngest to 115.5% in the oldest group. A positive correlation (r2 = 0.45) between estradiol concentration and skin moisture was observed on the 5th day of the cycle in 40- to 50-year-olds. For women on the 25th day of the menstruation cycle, estrogen concentration below the normal range was more beneficial for skin smoothness and pore width for the oldest group. The difference was not statistically significant (p > 0.05); how-ever, in the 40- to 50-year age group, skin smoothness was much better (43.5 ± 6.7%) for low estradiol while it was 37.5 ± 4.7% in the 20- to 29-year age group. Similarly, in the 40- to 50-year age group, skin pore width was much smaller (35.2 ± 15.7%) for low estradiol while it was 54.3 ± 28.8% in the 20- to 29-year age group.

CONCLUSIONS

Skin moisture was related to the concentration of estradiol only in the oldest examined group of women regardless of the phase of menstrual cycle. In the 40- to 50-year-old group of women, the low level of estradiol on the 25th day of the cycle is better used to maintain a good facial skin appearance and has a positive influence not only on skin moisture, but also on pore width and skin smoothness.

Androgenic and estrogenic indices in human newborns and infants: the MIREC-ID study

Prenatal sex steroid exposure plays an important role in determining child development. Yet, measurement of prenatal hormonal exposure has been limited by the paucity of newborn/infant data and the invasiveness of fetal hormonal sampling. Here we provide descriptive data from the MIREC-ID study (n=173 girls; 162 boys) on a range of minimally invasive physical indices thought to reflect prenatal exposure to androgens [anogenital distances (AGDs); penile length/width, scrotal/vulvar pigmentation], to estrogens [vaginal maturation index (VMI) - the degree of maturation of vaginal wall cells] or to both androgens/estrogens [2nd-to-4th digit ratio (2D:4D); areolar pigmentation, triceps/sub-scapular skinfold thickness, arm circumference]. VMI was found to be associated with triceps skinfold thickness (β=0.265, P=0.005), suggesting that this marker may be sensitive to estrogen levels produced by adipose tissue in girls. Both estrogenic and androgenic markers (VMI: β=0.338, P=0.031; 2D:4D - right: β=-0.207, P=0.040; left: β=-0.276, P=0.006; AGD-fourchette - β=0.253, P=0.036) were associated with areolar pigmentation in girls, supporting a role for the latter as an index of both androgen and estrogen exposure. We also found AGD-penis (distance from the anus to the penis) to be associated with scrotal pigmentation (β=0.290, P=0.048), as well as right arm circumference (β=0.462, P<0.0001), supporting the notion that these indices may be used together as markers of androgen exposure in boys. In sum, these findings support the use of several physical indices at birth to convey a more comprehensive picture of prenatal exposure to sex hormones.

Melasma: How hormones can modulate skin pigmentation

We described-along with a genetic predisposition and exposure to sunlight, as the main factors for melasma development-pregnancy, hormonal therapies, and oral contraceptive pills. Whilst hormonal alteration or therapies are frequently reported in literature in association with melasma, studies analyzing the laboratoristic correlation are limited. We review data published on hormones variations both in women and males with melasma and report some peculiar clinical cases that further demonstrate how the relationship between hormone secretion and melasma development is difficult to be defined.

The neuroendocrinology of sexual attraction

Sexual attraction has two components: Emission of sexually attractive stimuli and responsiveness to these stimuli. In rodents, olfactory stimuli are necessary but not sufficient for attraction. We argue that body odors are far superior to odors from excreta (urine, feces) as sexual attractants. Body odors are produced by sebaceous glands all over the body surface and in specialized glands. In primates, visual stimuli, for example the sexual skin, are more important than olfactory. The role of gonadal hormones for the production of and responsiveness to odorants is well established. Both the androgen and the estrogen receptor α are important in male as well as in female rodents. Also in primates, gonadal hormones are necessary for the responsiveness to sexual attractants. In males, the androgen receptor is sufficient for sustaining responsiveness. In female non-human primates, estrogens are needed, whereas androgens seem to contribute to responsiveness in women.

The relationship between menopausal hormone therapy and keratinocyte carcinoma: A review

Introduction

Keratinocyte carcinoma (KC) is the most common malignancy in the United States. The two most common forms of KC are basal cell carcinoma and squamous cell carcinoma (SCC), which account for 80% and 20% of cases, respectively.

Objective

There are many well-established risk factors for KC, but a more controversial risk factor for KC development is menopausal hormone therapy (MHT). This review synthesizes existing information on this topic and identifies knowledge gaps for future study.

Methods

A systematic review of the literature using the Medical Subject Headings terms “menopausal hormone therapy; skin neoplasms” was conducted in the PubMed database from March 19, 2018 to April 1, 2018. This yielded 168 articles, case reports, and reviews, which were further refined for inclusion during the development of this manuscript. Additional articles were identified from cited references.

Results

Four studies pertaining to this topic were identified. The results were evaluated in the context of these studies’ strengths and weaknesses. MHT contributes to an increased risk of basal cell carcinoma in Caucasian subjects and may make these tumors histologically more aggressive. There is not enough evidence to make a conclusion with regard to a potential relationship between MHT and SCC. However, one study suggested an increased risk of SCC with MHT use and another demonstrated a temporal association with prolonged MHT use and increased risk of SCC development.

Conclusion

Ever users of MHT should be screened more frequently for KC. This issue is of importance to dermatologists because patients who receive earlier diagnoses of KC will have a better opportunity to pursue treatment.

Pigmentation phototype and prostate and breast cancer in a select Spanish population-A Mendelian randomization analysis in the MCC-Spain study

INTRODUCTION

Phototype has been associated with an increased risk of prostate cancer, and it is yet unknown if it is related to other hormone-dependent cancers, such as breast cancer or whether this association could be considered causal.

METHODS

We examined the association between the phototype and breast and prostate cancers using a Mendelian randomization analysis. We studied 1,738 incident cases of breast cancer and another 817 cases of prostate cancer. To perform a Mendelian randomization analysis on the phototype-cancer relationship, a genetic pigmentation score was required that met the following criteria: (1) the genetic pigmentation score was associated with phototype in controls; (2) the genetic pigmentation score was not associated with confounders in the relationship between phototype and cancer, and (3) the genetic pigmentation score was associated with cancer only through its association with phototype. Once this genetic score is available, the association between genetic pigmentation score and cancer can be identified as the association between phototype and cancer.

RESULTS

The association between the genetic pigmentation score and phototype in controls showed that a higher genetic pigmentation score was associated with fair skin, blond hair, blue eyes and the presence of freckles. Applying the Mendelian randomization analysis, we verified that there was no association between the genetic pigmentation score and cancers of the breast and prostate.

CONCLUSIONS

Phototype is not associated with breast or prostate cancer.

Resveratrol: from diet to topical usage

The stilbene derivative resveratrol (3,5,4'-trihydroxy-stilbene; RESV) has become the subject of interest of many researchers and the pharmaceutical industries due to its well-acclaimed beneficial biological activities. Although earlier research tended to focus on the effects of RESV on cardiovascular disorders, many other studies have described the beneficial effects of RESV in the areas of cancer chemoprevention and inflammation and interest of researchers on this compound is still increasing. It is now well accepted that the effect of RESV is not just due to its so called "antioxidant" activity but mainly (if not only) because of the ability of this compound to trigger cell signaling pathways and gene expression involved in cellular defense systems. Many "in vitro" studies on RESV did not take into account that although its oral absorption is about 75% it undergoes rapid metabolism and the concentration in the blood stream is almost undetectable. For this reason interest in the topical usage of RESV by cosmeceutical skin care brands has exponentially increased in the last decade reporting in general very promising results on its beneficial effect in protecting the skin from outdoor insults, but there is still some controversy on its topical usage mainly surrounding the concentration used. Therefore, more basic research on the topical application of RESV should be performed to better understand the way it prevents cutaneous damage and whether it could be recommended as a preventive skin aging agent for all skin insults.

Blackcurrant Anthocyanins Increase the Levels of Collagen, Elastin, and Hyaluronic Acid in Human Skin Fibroblasts and Ovariectomized Rats

Blackcurrants (Ribes nigrum L.) contain high levels of anthocyanin polyphenols, which have beneficial effects on health, owing to their antioxidant and anticarcinogenic properties. Phytoestrogens are plant-derived substances with estrogenic activity, which could have beneficial effects on the skin. Estradiol secretion decreases during menopause, reducing extracellular matrix (ECM) component production by skin fibroblasts. Using a normal human female skin fibroblast cell line (TIG113) and ovariectomized rats, the present study investigated whether an anthocyanin-rich blackcurrant extract (BCE) and four blackcurrant anthocyanins have novel phytoestrogenic activities that could benefit the skin in menopausal women. In TIG113 cells, a microarray and the Ingenuity^® Pathway Analysis showed that 1.0 μg/mL of BCE upregulated the expression of many estrogen signaling-related genes. A quantitative RT-PCR analysis confirmed that BCE (1.0 or 10.0 μg/mL) and four types of anthocyanins (10 μM) altered the mRNA expression of ECM proteins and enzymes involved in ECM turnover. Immunofluorescence staining indicated that the anthocyanins stimulated the expression of ECM proteins, such as collagen (types I and III) and elastin. Dietary administration of 3% BCE to ovariectomized rats for 3 months increased skin levels of collagen, elastin, and hyaluronic acid. This is the first study to show that blackcurrant phytoestrogens have beneficial effects on skin experimental models.

Human colour in mate choice and competition

The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.

Innate Sex Bias of Staphylococcus aureus Skin Infection Is Driven by α-Hemolysin

Numerous studies have reported sex bias in infectious diseases, with bias direction dependent on pathogen and site of infection. Staphylococcus aureus is the most common cause of skin and soft tissue infections (SSTIs), yet sex bias in susceptibility to S. aureus SSTI has not been described. A search of electronic health records revealed an odds ratio of 2.4 for S. aureus SSTI in males versus females. To investigate the physiological basis of this bias, we compared outcomes between male and female mice in a model of S. aureus dermonecrosis. Consistent with the epidemiological data, female mice were better protected against SSTI, with reduced dermonecrosis followed later by increased bacterial clearance. Protection in females was disrupted by ovariectomy and restored by short-term estrogen administration. Importantly, this sex bias was mediated by a sex-specific response to the S. aureus-secreted virulence factor α-hemolysin (Hla). Infection with wild-type S. aureus suppressed inflammatory cytokine production in the skin of female, but not male, mice when compared with infection with an isogenic hla deletion mutant. This differential response was conserved following injection with Hla alone, demonstrating a direct response to Hla independent of bacterial burden. Additionally, neutrophils, essential for clearing S. aureus, demonstrated sex-specific S. aureus bactericidal capacity ex vivo. This work suggests that sex-specific skin innate responsiveness to Hla and neutrophil bactericidal capacity play important roles in limiting S. aureus SSTI in females. Understanding the molecular mechanisms controlling this sex bias may reveal novel targets to promote host innate defense against S. aureus skin infection.

Dietary Management of Skin Health: The Role of Genistein

In women, aging and declining estrogen levels are associated with several cutaneous changes, many of which can be reversed or improved by estrogen supplementation. Two estrogen receptors—α and β—have been cloned and found in various tissue types. Epidermal thinning, declining dermal collagen content, diminished skin moisture, decreased laxity, and impaired wound healing have been reported in postmenopausal women. Experimental and clinical studies in postmenopausal conditions indicate that estrogen deprivation is associated with dryness, atrophy, fine wrinkling, and poor wound healing. The isoflavone genistein binds to estrogen receptor β and has been reported to improve skin changes. This review article will focus on the effects of genistein on skin health.