Effect of estrogens on skin aging and the potential role of SERMs

Transcriptomics analysis reveals molecular alterations underpinning spaceflight dermatology

BACKGROUND

Spaceflight poses a unique set of challenges to humans and the hostile spaceflight environment can induce a wide range of increased health risks, including dermatological issues. The biology driving the frequency of skin issues in astronauts is currently not well understood.

METHODS

To address this issue, we used a systems biology approach utilizing NASA's Open Science Data Repository (OSDR) on space flown murine transcriptomic datasets focused on the skin, biochemical profiles of 50 NASA astronauts and human transcriptomic datasets generated from blood and hair samples of JAXA astronauts, as well as blood samples obtained from the NASA Twins Study, and skin and blood samples from the first civilian commercial mission, Inspiration4.

RESULTS

Key biological changes related to skin health, DNA damage & repair, and mitochondrial dysregulation are identified as potential drivers for skin health risks during spaceflight. Additionally, a machine learning model is utilized to determine gene pairings associated with spaceflight response in the skin. While we identified spaceflight-induced dysregulation, such as alterations in genes associated with skin barrier function and collagen formation, our results also highlight the remarkable ability for organisms to re-adapt back to Earth via post-flight re-tuning of gene expression.

CONCLUSION

Our findings can guide future research on developing countermeasures for mitigating spaceflight-associated skin damage.

Treatment of menopausal skin - A narrative review of existing treatments, controversies, and future perspectives

Menopause is a state of estrogen deficiency that affects numerous estrogen-dependent tissues in the female body. Skin is one of the most affected organs. Many consider menopausal skin changes to be merely an aesthetic problem; however, they can significantly affect women's quality of life. Currently, there are no approved effective treatments to prevent or alleviate skin changes associated with estrogen deficiency. Standard systemic hormone replacement therapy used to treat menopausal symptoms may be effective to some degree for skin treatment. In addition, compounded bioidentical hormone replacement therapy, selective estrogen receptor modulators, and phytoestrogens could also be used for skin treatment, although this is only hypothetical due to lack of data. Many questions therefore remain unanswered. On the other hand, topical, low-dose estrogen that would act only on the skin without systemic effects could be a possible option, as could be skin-only acting topical phytoestrogens. Such topical products without systemic effects could play a role in the treatment of menopausal skin. However, they are not currently approved because there is insufficient data on their safety and efficacy. A healthy lifestyle could have a positive effect on the menopausal skin. In this review, we provide an overview of the characteristics of menopausal skin, an outlook on the future treatment of menopausal skin with estrogens and other approaches, and the associated controversies and speculations. Overall, the importance of menopausal skin changes should not be neglected, and high-quality research is needed to gain new insights into the treatment of menopausal skin.

Therapeutic modulation of KIT ligand in melanocytic disorders with implications for mast cell diseases

KIT ligand and its associated receptor KIT serve as a master regulatory system for both melanocytes and mast cells controlling survival, migration, proliferation and activation. Blockade of this pathway results in cell depletion, while overactivation leads to mastocytosis or melanoma. Expression defects are associated with pigmentary and mast cell disorders. KIT ligand regulation is complex but efficient targeting of this system would be of significant benefit to those suffering from melanocytic or mast cell disorders. Herein, we review the known associations of this pathway with cutaneous diseases and the regulators of this system both in skin and in the more well-studied germ cell system. Exogenous agents modulating this pathway will also be presented. Ultimately, we will review potential therapeutic opportunities to help our patients with melanocytic and mast cell disease processes potentially including vitiligo, hair greying, melasma, urticaria, mastocytosis and melanoma.

Anti-aging Strategies and Topical Delivery of Biopolymer-based Nanocarriers for Skin Cancer Treatment

Environmental factors like UV radiation and epigenetic changes are significant factors for skin cancer that trigger early aging. This review provides essential information on cancer development concerning aging, the receptors involved, and the therapeutic targets. Biopolymers like polysaccharide, polyphenols, proteins, and nucleic acid plays a vital role in the regulation of normal cell homeostasis. Therefore, it is pertinent to explore the role of biopolymers as antiaging formulations and the possibility of these formulations being used against cancer via topical administrations. As UV radiation is one of the predominant factors in causing skin cancer, the association of receptors between aging and cancer indicated that insulin receptor, melatonin receptor, toll-like receptor, SIRT 1 receptor, tumor-specific T cell receptor and mitochondria-based targeting could be used to direct therapeutics for suppression of cancer and prevent aging. Biopolymer-based nanoformulations have tremendously progressed by entrapment of drugs like curcumin and resveratrol which can prevent cancer and aging simultaneously. Certain protein signaling or calcium and ROS signaling pathways are different for cancer and aging. The involvement of mitochondrial DNA mutation along with telomere shortening with a change in cellular energetics leading to genomic instability in the aging process can also induce mitochondrial dysfunction and epigenetic alterations leading to skin cancer. Therefore, the use of biopolymers as a topical supplement during the aging process can result in the prevention of cancer.

Targeting estrogen signaling and biosynthesis for aged skin repair

Non-healing skin wounds are disproportionally prevalent in older adults. Current treatments do not account for the particularities of aged skin and result in inadequate outcomes. Overall, healing chronic wounds in the elderly remains a major unmet clinical need. Estrogens play a critical role in reproduction but also have important actions in non-reproductive organs. Estrogen biosynthesis and signaling pathways are locally activated during physiological wound healing, processes that are inhibited in elderly estrogen-deprived skin. Estrogen deprivation has been shown to be a critical mediator of impaired wound healing in both postmenopausal women and aged men, and topical estrogen application reverses age-associated delayed wound healing in both elderly men and women. These data indicate that adequate estrogen biosynthesis and properly regulated estrogen signaling pathways are essential for normal wound healing and can be targeted to optimize tissue repair in the elderly. However, due to fundamental questions regarding how to safely restore estrogen signaling locally in skin wounds, there are currently no therapeutic strategies addressing estrogen deficiency in elderly chronic wounds. This review discusses established and recent literature in this area and proposes the hypothesis that estrogen plays a pleiotropic role in skin aging and that targeting estrogen signaling and biosynthesis could promote skin repair in older adults.

Soy Protein Containing Isoflavones Improves Facial Signs of Photoaging and Skin Hydration in Postmenopausal Women: Results of a Prospective Randomized Double-Blind Controlled Trial

Preliminary findings from multiple studies indicate that dietary intake of soy-derived isoflavones exert beneficial effects on the skin including defense against oxidant damage, stimulation of collagen synthesis, and increased hydration. This study aims to investigate how oral supplementation of a soy protein isolate with added isoflavones (SPII) affects components of photoaging such as facial wrinkles and dyspigmentation, and skin biophysical measures such as skin hydration and sebum excretion in postmenopausal women. This 6-month prospective, randomized double-blind controlled study was conducted on 44 postmenopausal women with Fitzpatrick skin types I, II, and III who were randomized to receive either casein protein or SPII. A high-resolution facial photography system was used to measure wrinkle severity and pigmentation at 0, 8, 16, and 24 weeks. Skin biophysical measurements included skin hydration and sebum production. The average wrinkle severity was decreased in the SPII intervention group at week 16 and week 24 by 5.9% and 7.1%, respectively, compared to the baseline. Compared to the casein group, average wrinkle severity was significantly decreased at week 16 (p < 0.05) and week 24 (p < 0.0001). Facial pigment intensity was decreased by -2.5% (p < 0.05) at week 24, whereas there was no significant change in the casein group. Compared to baseline, skin hydration in the SPII group was significantly increased by 39% and 68% on the left and right cheeks (p < 0.05), respectively, at 24 weeks. There were no significant differences in sebum production. Dietary soy protein supplementation with isoflavones may improve skin photoaging, including wrinkles and dyspigmentation, and increase skin hydration in postmenopausal women with Fitzpatrick skin types I, II, and III.

Evaluation of adapted dermocosmetic regimens for perimenopausal and menopausal women using an artificial intelligence-based algorithm and quality of life questionnaires: An open observational study

BACKGROUND

The decline in estrogen levels from several years before (perimenopause) and during menopause has various negative effects, including skin specific issues, which often receive less attention than other menopausal symptoms despite having a significant negative effect on quality of life (QoL). The objective of this study was to evaluate the effectiveness of anti-aging dermocosmetic products designed for women during the perimenopause and menopause.

MATERIALS AND METHODS

An open study of 101 perimenopausal women (no menstruation for 4-12 months or irregular menstruation for <5 years) and 101 menopausal women (no menstruation for >12 months), not taking hormone replacement therapy, was conducted. Adapted dermocosmetic regimens, specific to each group (day cream, night cream and serum), were applied for 56 days. Assessments included automatic artificial intelligence diagnostics of eight clinical facial signs, hydration and transepidermal water loss (TEWL), and a menopause skin QoL questionnaire.

RESULTS

Mean age was 50 ± 3.9 years (range 41-57) and 59 ± 3.8 years (range 50-66) for the perimenopause and menopause groups, respectively. Significant improvements in wrinkles and vascular signs, increases in hydration, decreases in TEWL, and a positive impact on QoL were observed after 56 days of application of the respective dermocosmetic regimens for both the perimenopause and menopause groups.

CONCLUSION

The anti-aging skin care products designed specifically for perimenopausal and menopausal women increased skin hydration and improved wrinkles with a positive impact on QoL.

In Silico Prediction of Human Organ Toxicity via Artificial Intelligence Methods

Unpredicted human organ level toxicity remains one of the major reasons for drug clinical failure. There is a critical need for cost-efficient strategies in the early stages of drug development for human toxicity assessment. At present, artificial intelligence methods are popularly regarded as a promising solution in chemical toxicology. Thus, we provided comprehensive in silico prediction models for eight significant human organ level toxicity end points using machine learning, deep learning, and transfer learning algorithms. In this work, our results showed that the graph-based deep learning approach was generally better than the conventional machine learning models, and good performances were observed for most of the human organ level toxicity end points in this study. In addition, we found that the transfer learning algorithm could improve model performance for skin sensitization end point using source domain of in vivo acute toxicity data and in vitro data of the Tox21 project. It can be concluded that our models can provide useful guidance for the rapid identification of the compounds with human organ level toxicity for drug discovery.

Skin chronological aging drives age-related bone loss via secretion of cystatin-A

Although clinical evidence has indicated an association between skin atrophy and bone loss during aging, their causal relationship and the underlying mechanisms are unknown. Here we show that premature skin aging drives bone loss in mice. We further identify that cystatin-A (Csta), a keratinocyte-enriched secreted factor, mediates the effect of skin on bone. Keratinocyte-derived Csta binds the receptor for activated C-kinase 1 in osteoblast and osteoclast progenitors, thus promoting their proliferation but inhibiting osteoclast differentiation. Csta secretion decreases with skin aging in both mice and humans, thereby causing senile osteoporosis by differentially decreasing the numbers of osteoblasts and osteoclasts. In contrast, topical application of calcipotriol stimulates Csta production in the epidermis and alleviates osteoporosis. These results reveal a mode of endocrine regulation of bone metabolism in the skin, and identify Csta as an epidermally derived hormone linking skin aging to age-related bone loss. Enhancers of skin Csta levels could serve as a potential topical drug for treatment of senile osteoporosis.

Factors Influencing Skin Aging and the Important Role of Estrogens and Selective Estrogen Receptor Modulators (SERMs)

The narrative for this overview focuses on updating the factors that influence skin aging and the important role estrogens and selective estrogen receptor modulators (SERMs) play in this process (mainly utilizing journal reports and reviews from the last four years). Estrogens have been known and studied for over a century. For many years, it has been recognized that estrogens are important in the maintenance of human skin. Women seek cosmetic and medical treatments to improve dermal health and physical characteristics to enhance their self-perception and inhibit skin aging, particularly in highly visible body areas. The goal: to retain estrogen’s positive benefits while aging and especially at/after menopause where estrogen-deficient skin contributes to the dramatic decline in skin health. In this overview, both background information and recent novel findings are included that cover aging (general mechanisms), skin aging, and factors that influence skin aging (intrinsic, extrinsic, skin microbiome and gut microbiome.) Plus, estrogen’s general role in maintaining skin health is presented through the classical estrogen receptors alpha (α) and beta (β) and non-classical (or non-genomic) estrogen receptor (G protein-coupled seven transmembrane receptor). More importantly, the various benefits of 17β-estradiol in skin health are examined (ie, skin collagen and elastin profiles that follow 17β-estradiol levels during aging and at/after menopause). Finally, a revision of information for estrogenic skin topical applications involving isoflavonoid compounds that act as SERMs, but are classified as endocrine disruptors, and a topical estrogen analog are explored to update the known and unknown characteristics of these treatments. Further study is warranted to understand the biological and molecular mechanisms by which estrogens support and enhance dermal health and wellbeing.

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.

Genital Wound Repair and Scarring

Skin wound repair has been the central focus of clinicians and scientists for almost a century. Insights into acute and chronic wound healing as well as scarring have influenced and ameliorated wound treatment. Our knowledge of normal skin notwithstanding, little is known of acute and chronic wound repair of genital skin. In contrast to extra-genital skin, hypertrophic scarring is uncommon in genital tissue. Chronic wound healing disorders of the genitals are mostly confined to mucosal tissue diseases. This article will provide insights into the differences between extra-genital and genital skin with regard to anatomy, physiology and aberrant wound repair. In light of fundamental differences between genital and normal skin, it is recommended that reconstructive and esthetic surgery should exclusively be performed by specialists with profound expertise in genital wound repair.

Correlation of Body Mass Index with Epidermal Biophysical Properties Varies with Gender in Chinese

Background

Epidermal function is associated with diabetes and renal disease. Whether obesity can reflect the changes in epidermal function is not clear yet.

Objective

We assessed here the correlation of epidermal functions with body mass index (BMI) in a large Chinese cohort.

Methods and Subjects

A total of 1,405 Chinese aged 21–98 years old were enrolled in this study. Epidermal functions, including transepidermal water loss (TEWL), stratum corneum hydration, and skin surface pH, were measured on the flexor forearm and the shin. Subjects' height and body weight were also measured.

Results

Age positively correlated with both TEWL and skin surface pH, while it negatively correlated with stratum corneum hydration on both the forearm and the shin of females. Similarly, age positively correlated with skin surface pH, while negatively correlating with stratum corneum hydration on both the forearm and the shin of males. In females, BMI positively correlated with skin surface pH, while it negatively correlated with stratum corneum hydration on both the forearm and the shin. However, BMI correlated neither with skin surface pH on both the forearm and the shin nor with stratum corneum hydration on the shin of males.

Conclusion

These results demonstrate that correlations of BMI with age and epidermal functions vary with gender.

Skin as an endocrine organ: A narrative review

Skin being the largest organ of the body, is equipped with numerous functional properties. Over the past few years, intricate research into the biology of skin has led to a gamut of discoveries. Skin is now regarded as one of the most vital endocrine organs. The skin contains equivalents of the hypothalamo-pituitary-adrenal axis, hypothalamo-pituitary-thyroid axis and the appendages produce multiple hormones such as Vitamin D, sex steroids, retinoids and opioids. In this article, we will explore the role of skin as a target and source of some of the hormones of the human body, and briefly touch on the clinical applications.

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.

Phytoestrogens (Resveratrol and Equol) for Estrogen-Deficient Skin-Controversies/Misinformation versus Anti-Aging In Vitro and Clinical Evidence via Nutraceutical-Cosmetics

The overarching theme for this review is perspective. Superfoods (a marketing term for fruits and vegetables, etc.) have a positive connotation, while many superfoods contain phytoestrogens, a term that is alarming to the public and has a negative connotation because phytoestrogens are endocrine-disruptors, even though they are strong antioxidants that have many health benefits. To understand phytoestrogens, this paper provides a brief summary of the characteristics of: (a) estrogens, (b) estrogen receptors (ER), (c) estrogen-deficient skin, (d) how perspective(s) get off track, (e) phytoestrogen food sources, and (f) misconceptions of phytoestrogens and food safety, in general, that influence person(s) away from what is true. Finally, a brief history of cosmetics to nutraceuticals is covered plus the characteristics of phytoestrogens, resveratrol and equol on: (g) estrogen receptor binding, (h) topical and oral dosing, and (i) in vitro, molecular mechanisms and select clinical evidence, where both phytoestrogens (resveratrol and equol) demonstrate promising applications to improve skin health is presented along with future directions of nutraceuticals. Perspective is paramount in understanding the controversies associated with superfoods, phytoestrogens, and endocrine-disruptors because they have both positive and negative connotations. Everyone is exposed to and consumes these molecules everyday regardless of age, gender, or geographic location around the world, and how we understand this is a matter of perspective.

Profile shape variation and sexual dimorphism amongst middle-aged Northern Europeans

AIM

To explore profile shape variation in a large population of middle-aged individuals and investigate features of sexual dimorphism.

MATERIALS AND METHODS

Facial profile photographs of 1776 individuals (964 females and 812 males; 46 years old), members of the Northern Finland Birth Cohort 1966 (NFBC1966), were uploaded and digitized with Viewbox software. Profile shape was defined with 47 landmarks (4 fixed and 43 sliding semi-landmarks). Digitized images were reoriented and scaled with Procrustes Superimposition, and shape variation was determined with a Principal Component Analysis.

RESULTS

More than 90 per cent of profile shape variation was explained by Principal Components (PC) 1-9. PC1, explaining the largest amount of variation (33.1 per cent) described changes in facial convexity, slope of the forehead, lip, and chin protuberance. PC2 (23.1 per cent variation) was more related to vertical changes of the lower facial third and PC3 (11 per cent variation) primarily described changes in lip protrusion and nasal projection. Shape analysis showed a significant difference between the average female and the average male profile shape (P < 0.001); however, this was not evident upon visual observation. The shape variable most associated with sex was PC3 (η 2 = 0.245; P < 0.001), which described changes in lip prominence and in projection of the dorsal nasal surface. An additional discriminant analysis showed that profile shape predicted sex in 76 per cent of males and 79.6 per cent of females.

CONCLUSIONS

There is significant sexual dimorphism in facial profile among middle-aged adults. Profile shape variation was associated to changes in lip protrusion, nasal protuberance, and chin projection.

Menopause and the Skin: Old Favorites and New Innovations in Cosmeceuticals for Estrogen-Deficient Skin

Estrogen is a pivotal signaling molecule; its production is regulated by the expression of the aromatase (CYP19A1) gene from ovarian and peripheral tissue sites, and it is transmitted via estrogen receptors to influence many important biological functions. However, the narrative for this overview focuses on the decline of 17β-estradiol levels from ovarian sites after menopause. This estrogen-deficient condition is associated with a dramatic reduction in skin health and wellness by negatively impacting dermal cellular and homeostatic mechanisms, as well as other important biological functions. The changes include loss of collagen, elastin, fibroblast function, vascularity, and increased matrix metalloproteinase(s) enzymatic activities, resulting in cellular and extracellular degradation that leads to dryness, wrinkles, atrophy, impaired wound healing/barrier function, decreased antioxidant capacity [i.e., defense against reactive oxygen species (ROS) and oxidative stress], decreased attractiveness and psychological health, and increased perception of aging. While topical estrogen may reverse these changes, the effects of today's low-dose systemic hormone treatments are not well established, raising the need for more concentrated local administration of hormones or newer cosmeceutical agents such as selective estrogen receptor modulators (SERMs), including phytoestrogens that have become major active ingredients for skin care products, especially when addressing estrogen-deficient skin. Two example compounds are presented, an analog of resveratrol (i.e., 4'-acetoxy resveratrol) and the isoflavonoid equol, both of which are involved in a variety of biochemical/molecular actions and mechanisms, as demonstrated via in vitro and clinical studies that enhance human dermal health, especially in estrogen-deficient skin.

Estrogen deficiency - a central paradigm in age-related impaired healing?

Wound healing is a dynamic biological process achieved through four sequential, overlapping phases; hemostasis, inflammation, tissue proliferation and remodeling. For effective wound healing, all four phases must occur in the appropriate order and time frame. It is well accepted that the wound healing process becomes disrupted in the elderly, increasing the propensity of non-healing wound states that can lead to substantial patient morbidity and an enormous financial burden on healthcare systems. Estrogen deprivation in the elderly has been identified as the key driver of age-related delayed wound healing in both genders, with topical and systemic estrogen replacement reversing the detrimental effects of aging on wound repair. Evidence suggests estrogen deprivation may contribute to the development of chronic wound healing states in the elderly but research in this area is somewhat limited, warranting further investigations. Moreover, although the beneficial effects of estrogen on cutaneous healing have been widely explored, the development of estrogen-based treatments to enhance wound repair in the elderly have yet to be widely exploited. This review explores the critical role of estrogen in reversing age-related impaired healing and evaluates the prospect of developing more focused novel therapeutic strategies that enhance wound repair in the elderly via activation of specific estrogen signaling pathways in regenerating tissues, whilst leaving non-target tissues largely unaffected.

Selective Estrogen Receptor Modulators: A Potential Option For Non-Binary Gender-Affirming Hormonal Care?

Gender dysphoria describes the distress associated with having a gender identity that differs from one's birth-assigned sex. To relieve this distress, transgender, and gender diverse (henceforth, trans) individuals commonly undergo medical transition involving hormonal treatments. Current hormonal treatment guidelines cater almost exclusively for those who wish to transition from male to female or vice versa. In contrast, there is a dearth of hormonal options for those trans individuals who identify as non-binary and seek an androgynous appearance that is neither overtly male nor female. Though prolonged puberty suppression with gonadotrophin releasing hormone agonists (GnRHa) could in theory be gender-affirming by preventing the development of unwanted secondary sex characteristics, this treatment option would be limited to pre- or peri-pubertal adolescents and likely have harmful effects. Here, we discuss the theoretical use of Selective Estrogen Receptor Modulators (SERMs) for non-binary people assigned male at birth (AMAB) who are seeking an androgynous appearance through partial feminization without breast growth. Given their unique range of pharmacodynamic effects, SERMs may represent a potential gender-affirming treatment for this population, but there is a lack of knowledge regarding their use and potentially adverse effects in this context.

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.

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.

Dermatologic adverse events related to the PI3Kα inhibitor alpelisib (BYL719) in patients with breast cancer

PURPOSE

Rash develops in approximately 50% of patients receiving alpelisib for breast cancer, often requiring dose modifications. Here, we describe the clinicopathologic, laboratory, and management characteristics of alpelisib-related dermatologic adverse events (dAEs).

METHODS

A single center-retrospective analysis was conducted. Data were abstracted from electronic medical records.

RESULTS

A total of 102 patients (mean age 56 years, range 27-83) receiving alpelisib most frequently in combination with endocrine therapy (79, 77.5%) were included. We identified 41 (40.2%) patients with all-grade rash distributed primarily along the trunk (78%) and extremities (70%) that developed approximately within two weeks of treatment initiation (mean 12.8 ± 1.5 days) and lasted one-week (mean duration 7.1 ± 0.8 days). Of 29 patients with documented morphology of alpelisib-related dAEs, 26 (89.7%) had maculopapular rash. Histology showed perivascular and interface lymphocytic dermatitis. All-grade rash correlated with an increase in serum eosinophils from 2.7 to 4.4%, p < 0.05, and prophylaxis with non-sedating antihistamines (n = 43) was correlated with a reduction of grade 1/2 rash (OR 0.39, p = 0.09). Sixteen (84.2%) of 19 patients with grade 3 dAEs resulted in interruption of alpelisib, which were managed with antihistamines, topical and systemic corticosteroids. We did not observe rash recurrence in 12 (75%) patients who were re-challenged.

CONCLUSIONS

A maculopapular rash associated with increased blood eosinophils occurs frequently with alpelisib. While grade 3 rash leads to alpelisib therapy interruption, dermatologic improvement is evident with systemic corticosteroids; and most patients can continue oncologic treatment at a maintained or reduced dose upon re-challenge with alpelisib.

Breast cancer pathogenesis is linked to the intra-tumoral estrogen sulfotransferase (hSULT1E1) expressions regulated by cellular redox dependent Nrf-2/NFκβ interplay

BACKGROUND

Estrogen sulfotransferase catalyzes conjugation of sulfuryl-group to estradiol/estrone and regulates E2 availability/activity via estrogen-receptor or non-receptor mediated pathways. Sulfoconjugated estrogen fails to bind estrogen-receptor (ER). High estrogen is a known carcinogen in postmenopausal women. Reports reveal a potential redox-regulation of hSULT1E1/E2-signalling. Further, oxidatively-regulated nuclear-receptor-factor 2 (Nrf2) and NFκβ in relation to hSULT1E1/E2 could be therapeutic-target via cellular redox-modification.

METHODS

Here, oxidative stress-regulated SULT1E1-expression was analyzed in human breast carcinoma-tissues and in rat xenografted with human breast-tumor. Tumor and its surrounding tissues were obtained from the district-hospital. Intracellular redox-environment of tumors was screened with some in vitro studies. RT-PCR and western blotting was done for SULT1E1 expression. Immunohistochemistry was performed to analyze SULT1E1/Nrf2/NFκβ localization. Tissue-histoarchitecture/DNA-stability (comet assay) studies were done.

RESULTS

Oxidative-stress induces SULT1E1 via Nrf2/NFκβ cooperatively in tumor-pathogenesis to maintain the required proliferative-state under enriched E2-environment. Higher malondialdehyde/non-protein-soluble-thiol with increased superoxide-dismutase/glutathione-peroxidase/catalase activities was noticed. SULT1E1 expression and E2-level were increased in tumor-tissue compared to their corresponding surrounding-tissues.

CONCLUSIONS

It may be concluded that tumors maintain a sustainable oxidative-stress through impaired antioxidants as compared to the surrounding. Liver-tissues from xenografted rat manifested similar E2/antioxidant dysregulations favoring pre-tumorogenic environment.

Sexual dimorphism in atrophic effects of topical glucocorticoids is driven by differential regulation of atrophogene REDD1 in male and female skin

Topical glucocorticoids, well-known anti-inflammatory drugs, induce multiple adverse effects, including skin atrophy. The sex-specific effects of systemic glucocorticoids are known, but sexual dimorphism of therapeutic and side effects of topical steroids has not been studied. We report here that female and male mice were equally sensitive to the anti-inflammatory effect of glucocorticoid fluocinolone acetonide (FA) in ear edema test. At the same time, females were more sensitive to FA-induced skin atrophy. We recently reported that REDD1 (regulated in development and DNA damage 1) plays central role in steroid atrophy. We found that REDD1 was more efficiently activated by FA in females, and that REDD1 knockout significantly protected female but not male mice from skin atrophy. Studies using human keratinocytes revealed that both estradiol and FA induced REDD1 mRNA/protein expression, and cooperated when they were combined at low doses. Chromatin immunoprecipitation analysis confirmed that REDD1 is an estrogen receptor (ER) target gene with multiple estrogen response elements in its promoter. Moreover, experiments with GR and ER inhibitors suggested that REDD1 induction by these hormones was interdependent on functional activity of both receptors. Overall, our results are important for the development of safer GR-targeted therapies suited for female and male dermatological patients.

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.

Acute body sodium depletion induces skin sodium mobilization in female Wistar rats

NEW FINDINGS

What is the central question of this study? Can Na⁺ depletion mobilize Na⁺ from the skin reservoir in ovariectomized rats? Does oestrogen replacement change the amount and the dynamics of skin Na⁺ storage? Is the reduced salt appetite after Na⁺ depletion in ovariectomized rats with oestrogen replacement related to changes in the skin Na⁺ ? What is the main finding and its importance? This work demonstrated that acute body Na⁺ depletion induced by frusemide mobilized the osmotically inactive skin Na⁺ reservoir to become osmotically active. Oestrogen treatment decreased the induced Na⁺ intake in ovariectomized rats but did not modulate the inactive Na⁺ reservoir in control conditions or its mobilization induced by Na⁺ depletion.

ABSTRACT

Oestradiol, which is an important hormone for water and electrolyte balance, also has a role in the inhibition of induced Na⁺ appetite. Sodium can be stored in the skin in osmotically active or inactive forms, and this skin Na⁺ reservoir may be involved in the control of body Na⁺ levels during physiopathological challenges. In this study, we investigated whether the effect of sodium depletion by frusemide can mobilize Na⁺ from the skin reservoir and whether oestradiol replacement changes or mobilizes the Na⁺ reserves in the skin. Ovariectomized Wistar rats were treated with vehicle or oestradiol for 7 days to evaluate the effects of oestrogen on the hydroelectrolyte balance, intake responses and skin Na⁺ and water content in basal conditions. Furthermore, the effects of oestrogen were evaluated after 24 h frusemide-induced whole-body Na⁺ depletion. Oestradiol-replaced rats exhibited reduced water intake without any significant changes in salt intake, Na⁺ excretion or water and Na⁺ skin content in basal conditions. After sodium depletion, both vehicle- and oestradiol-treated rats exhibited an increase in the osmotically active skin Na⁺ , which was associated with a decrease of the inactive skin Na⁺ reservoir. Oestrogen decreased the hypertonic saline intake induced by Na⁺ depletion, but it was not associated with any significant changes in the skin Na⁺ reservoir. Thus, sodium depletion is able to change the inactive-active skin Na⁺ reservoir balance. However, the oestrogenic modulation of sodium appetite after Na⁺ depletion is probably not related to the action of this hormone in the skin Na⁺ reservoir balance.

Aging in skin of color

Ethnic skin is quickly emerging as the norm in the United States, and as the population becomes more diverse, there is also a projected rise in the number of aging adults. Given the paucity of data regarding aging in ethnic skin, the authors have consolidated available information for this population. Literature examining structural and functional variation of aging in ethnic skin types was primarily found through PubMed and supplemental textbook chapters. Aging is comprised of two synergistic processes, intrinsic or chronologic aging, and extrinsic aging. Caucasian, African American, East Asian, and Hispanic skin each have distinguishing features of aging, but all populations share dyspigmentation, rhytides, and skin laxity. Increased melanin content predisposes skin of color to a greater degree of hyperpigmentation, but skin thickness may protect against the formation of rhytides. Tailored prevention and treatment are also paramount in attaining favorable outcomes for this growing cohort.

Dermatologic Conditions in Transgender Populations

Transgender persons receiving gender-affirming hormone therapy and procedures may face specific skin conditions. Skin diseases in transgender patients often are underdiagnosed and underrecognized despite their important impact on quality of life and mental health. This article discusses pathophysiology, diagnosis, and treatment of common skin diseases in the transgender populations. For transmasculine patients, conditions include acne vulgaris and male pattern hair loss. For transfeminine patients, conditions include hirsutism, pseudofolliculitis barbae, and melasma. Postprocedural keloids and other cutaneous complications are discussed. Unique aspects of skin health in transgender persons should be considered in the context of multidisciplinary gender-affirming care.

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.

The Protective Roles of Estrogen Receptor β in Renal Calcium Oxalate Crystal Formation via Reducing the Liver Oxalate Biosynthesis and Renal Oxidative Stress-Mediated Cell Injury

Females develop kidney stones less frequently than males do. However, it is unclear if this gender difference is related to altered estrogen/estrogen receptor (ER) signaling. Here, we found that ER beta (ERβ) signals could suppress hepatic oxalate biosynthesis via transcriptional upregulation of the glyoxylate aminotransferase (AGT1) expression. Results from multiple in vitro renal cell lines also found that ERβ could function via suppressing the oxalate-induced injury through increasing the reactive oxygen species (ROS) production that led to a decrease of the renal calcium oxalate (CaOx) crystal deposition. Mechanism study results showed that ERβ suppressed oxalate-induced oxidative stress via transcriptional suppression of the NADPH oxidase subunit 2 (NOX2) through direct binding to the estrogen response elements (EREs) on the NOX2 5′ promoter. We further applied two in vivo mouse models with glyoxylate-induced renal CaOx crystal deposition and one rat model with 5% hydroxyl-L-proline-induced renal CaOx crystal deposition. Our data demonstrated that mice lacking ERβ (ERβKO) as well as mice or rats treated with ERβ antagonist PHTPP had increased renal CaOx crystal deposition with increased urinary oxalate excretion and renal ROS production. Importantly, targeting ERβ-regulated NOX2 with the NADPH oxidase inhibitor, apocynin, can suppress the renal CaOx crystal deposition in the in vivo mouse model. Together, results from multiple in vitro cell lines and in vivo mouse/rat models all demonstrate that ERβ may protect against renal CaOx crystal deposition via inhibiting the hepatic oxalate biosynthesis and oxidative stress-induced renal injury.

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.

Estrogen-Dependent Nrf2 Expression Protects Against Reflux-Induced Esophagitis

BACKGROUND

Gastroesophageal reflux disease is more common in males than in females. The enhanced antioxidative capacity of estrogen in females might account for the gender difference. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in the host defense mechanism against oxidative stress.

AIMS

This study aimed to clarify the role of Nrf2 in reflux-induced esophageal inflammation, focusing on the gender difference and nitric oxide.

METHODS

Gastroesophageal reflux was surgically induced in male and female rats. Nitrite and ascorbic acid were administered for 1 week to provoke nitric oxide in the esophageal lumen. Male rats with gastroesophageal reflux were supplemented with 17β-estradiol or tert-butylhydroquinone, an Nrf2-inducing reagent. Esophageal squamous cell carcinoma KYSE30 cells were treated with 17β-estradiol. Nrf2 expression was examined by Western blotting and quantitative real-time PCR. Antioxidant gene expression profiles were examined by a PCR array.

RESULTS

In the presence of nitric oxide, reflux-induced esophageal damage was less evident, whereas esophageal expression of Nrf2 and its target genes such as Nqo1 was more evident in female or male rats supplemented with 17β-estradiol than in male rats. 17β-Estradiol increased nuclear Nrf2 expression in KYSE30 cells. tert-Butylhydroquinone increased tissue Nqo1 mRNA expression, leading to a reduction in reflux-induced esophageal damage.

CONCLUSIONS

Estrogen-dependent Nrf2 expression might contribute to protection against the development of gastroesophageal reflux disease in females.

Hepatocyte-generated 27-hydroxycholesterol promotes the growth of melanoma by activation of estrogen receptor alpha

Cholesterol plays an important role in maintaining normal physiological function of human body. However, excessive intake will induce a series of diseases including cancer. For melanoma, the relationship between hypercholesterolemia and its incidence remains unknown. The cholesterol metabolite 27-hydroxy cholesterol (27-HC) catalyzed by CYP27A1 has been reported to activate estrogen receptor (ER). As studies have indicated that melanoma expresses ER, we designed experiments to explore whether 27-HC could link hypercholesterolemia and melanoma. In this study, hepatocyte-specific CYP27A1^-/- mice were generated by CRISPR/Cas9 technology. The results revealed that high-cholesterol diet induced metabolism disorder and promoted the melanoma growth through 27-HC. Further study found that 27-HC promoted the growth of melanoma cells by activating ERα and eliciting the AKT and MAPK signaling pathway. This study puts forward the important role of 27-HC in the development of melanoma for the first time, links hypercholesterolemia with melanoma progression. The research also provides the rationale for the use of tamoxifen in melanoma therapy. The levels of 27-HC in blood could act as a novel biomarker for tamoxifen treatment in melanoma patients.

Estrogen Effects on Wound Healing

Wound healing is a physiological process, involving three successive and overlapping phases—hemostasis/inflammation, proliferation, and remodeling—to maintain the integrity of skin after trauma, either by accident or by procedure. Any disruption or unbalanced distribution of these processes might result in abnormal wound healing. Many molecular and clinical data support the effects of estrogen on normal skin homeostasis and wound healing. Estrogen deficiency, for example in postmenopausal women, is detrimental to wound healing processes, notably inflammation and re-granulation, while exogenous estrogen treatment may reverse these effects. Understanding the role of estrogen on skin might provide further opportunities to develop estrogen-related therapy for assistance in wound healing.

Novel Mechanism for Buffering Dietary Salt in Humans: Effects of Salt Loading on Skin Sodium, Vascular Endothelial Growth Factor C, and Blood Pressure

High dietary sodium intake triggers increased blood pressure (BP). Animal studies show that dietary salt loading results in dermal Na⁺ accumulation and lymphangiogenesis mediated by VEGF-C (vascular endothelial growth factor C), both attenuating the rise in BP. Our objective was to determine whether these mechanisms function in humans. We assessed skin electrolytes, BP, and plasma VEGF-C in 48 healthy participants randomized to placebo (70 mmol sodium/d) and slow sodium (200 mmol/d) for 7 days. Skin Na⁺ and K⁺ concentrations were measured in mg/g of wet tissue and expressed as the ratio Na⁺:K⁺ to correct for variability in sample hydration. Skin Na⁺:K⁺ increased between placebo and slow sodium phases (2.91±0.08 versus 3.12±0.09; P=0.01). In post hoc analysis, there was a suggestion of a sex-specific effect, with a significant increase in skin Na⁺:K⁺ in men (2.59±0.09 versus 2.88±0.12; P=0.008) but not women (3.23±0.10 versus 3.36±0.12; P=0.31). Women showed a significant increase in 24-hour mean BP with salt loading (93±1 versus 91±1 mm Hg; P<0.001) while men did not (96±2 versus 96±2 mm Hg; P=0.91). Skin Na⁺:K⁺ correlated with BP, stroke volume, and peripheral vascular resistance in men but not in women. No change was noted in plasma VEGF-C. These findings suggest that the skin may buffer dietary Na⁺, reducing the hemodynamic consequences of increased salt, and this may be influenced by sex.

Sexually Dimorphic Faciometrics in Humans From Early Adulthood to Late Middle Age: Dynamic, Declining, and Differentiated

Faciometrics have widely been used in contemporary studies on gender-related behavioral traits, for example, perceived and actual aggression, co-operation and trustworthiness, prejudicial beliefs, unethical behavior, and achievement drive, as well as, but to a lesser degree, in nonhuman primates. For the large part, these studies have focused primarily on "student-aged" populations with little empirical scrutiny regarding the efficacy of applying these measures with older participants. This study therefore investigated sexual dimorphism across four age-groups (20s, 30s, 40s, and 50s) in 444 participants (225 men). The expected sexual dimorphism was seen in the youngest age group in three of the four indices. The facial width to height ratio, however, although most commonly used empirically, was not found to be significantly different between men and women, consistent with more recent literature. Importantly, as age increased, sexual dimorphism decreased, but this was not consistent across all measures of it. Rather, it is evident that differing measures of sexual dimorphism follow distinct developmental trajectories. The only single marker which remained significantly different across all age-groups was cheekbone prominence. Sexual dimorphic faciometrics are therefore dynamic, declining, and differentiated through adulthood. Consequently, it is concluded that care should be taken in using faciometrics in studies involving older populations and that more research is needed to understand the impact of these distinct faciometric trajectories in gender- and masculinity-related studies.

Morphological Characteristics of Residual Skin Surface Components Collected from the Surface of Facial Skin in Women of Different Age

Background

Problems of skin aging and its prevention currently attract increasing attention with the growth of human life expectancy. The morphology of the stratum corneum (SC) is well known, but investigation of age-related changes of its structure is difficult in the absence of non-invasive sampling methods. The residual skin surface components (RSSC) that overlay the SC can be easily collected non-invasively.

Objective

The aim of this study was to examine morphology of RSSC samples collected from the surface of facial skin of healthy female volunteers of different age.

Methods

RSSC samples were non-invasively collected from 53 adult female volunteers (22 aged in the range 18∼25 years and 31 aged in the range 50∼73 years). The samples were analysed microscopically.

Results

Distinct age-related changes were determined for lipid droplet size, corneocyte desquamation level and lipid crystal count. There was a significant (p=0.0006) decrease in lipid droplet size among older women. Similarly, significantly (p=0.0401) lower lipid crystal numbers were present in the older group. Conversely, corneocyte desquamation was significantly higher (p=0.0007) in older women. No age-related difference in microbial presence in the RSSC could be detected. Result patterns were generally similar to those previously found in male volunteers; however gender-related differences in the absolute values were revealed.

Conclusion

Non-invasively collected RSSC samples allow identifying age-related changes on facial skin surface. The results of this study highlight gender-dependence of distinct elements of age-associated impairment of epidermal barrier and can be employed for developing new approaches to prevent changes associated with skin aging.

Steroid Hormones Are Key Modulators of Tissue Mechanical Function via Regulation of Collagen and Elastic Fibers

The extracellular matrix (ECM) plays an active and dynamic role that both reflects and facilitates the functional requirements of a tissue. The mature ECM of the nonpregnant cervix is drastically reorganized during pregnancy to drive changes in tissue mechanics that ensure safe birth. In this study, our research on mice deficient in the proteoglycan decorin have led to the finding that progesterone and estrogen play distinct and complementary roles to orchestrate structural reorganization of both collagen and elastic fibers in the cervix during pregnancy. Abnormalities in collagen and elastic fiber structure and tissue mechanical function evident in the cervix of nonpregnant and early pregnant decorin-null mice transiently recover for the remainder of pregnancy only to return 1 month postpartum. Consistent with the hypothesis that pregnancy levels of progesterone and estrogen may regulate ECM organization and turnover, expressions of factors required for assembly and synthesis of collagen and elastic fibers are temporally regulated, and the ultrastructure of collagen fibrils and elastic fibers is markedly altered during pregnancy in wild-type mice. Finally, utilizing ovariectomized nonpregnant decorin-null mice, we demonstrate structural resolution of collagen and elastic fibers by progesterone or estrogen, respectively, and the potential for both ECM proteins to contribute to mechanical function. These investigations advance understanding of regulatory factors that drive specialized ECM organization and contribute to an understanding of the cervical remodeling process, which may provide insight into potential complications associated with preterm birth that impact 9.6% of live births in the United States.

The Effects of Dietary Macronutrient Balance on Skin Structure in Aging Male and Female Mice

Nutrition influences skin structure; however, a systematic investigation into how energy and macronutrients (protein, carbohydrate and fat) affects the skin has yet to be conducted. We evaluated the associations between macronutrients, energy intake and skin structure in mice fed 25 experimental diets and a control diet for 15 months using the Geometric Framework, a novel method of nutritional analysis. Skin structure was associated with the ratio of dietary macronutrients eaten, not energy intake, and the nature of the effect differed between the sexes. In males, skin structure was primarily associated with protein intake, whereas in females carbohydrate intake was the primary correlate. In both sexes, the dermis and subcutaneous fat thicknesses were inversely proportional. Subcutaneous fat thickness varied positively with fat intake, due to enlarged adipocytes rather than increased adipocyte number. We therefore demonstrated clear interactions between skin structure and macronutrient intakes, with the associations being sex-specific and dependent on dietary macronutrient balance.