A prospective, randomized, double-blind, placebo-controlled study on the influence of a hormone replacement therapy on skin aging in postmenopausal women

Summary of the 2023 Thai Menopause Society Clinical Practice Guideline on Menopausal Hormone Therapy

The Thai Menopause Society is an academic organization consisting of healthcare professionals engaged in menopause medicine. The position statement was first issued in 1994 and updated in 2003 and 2023. Herein, we reviewed the important updates of the 2023 position statement on menopausal hormone therapy (MHT) as an international reference for healthcare professionals in Thailand. An advisory panel of clinicians and research experts in the field of menopause reviewed the recommendation of published International Consensus Statements and updated the evidence using the MEDLINE database through PubMed. The evidence-based information and relevant publications were assessed, and a consensus on recommendations was subsequently achieved using the level of evidence to determine the recommendation strength and evidence quality. MHT remains the most effective treatment for vasomotor symptoms and genitourinary syndromes of menopause even after 20 years. Additionally, it is effective in preventing bone loss and fractures in postmenopausal women. The cardiovascular risk of MHT increased in women who initiated MHT after 60 years of age. Hormone therapy should be individualized following the hormone type, dose, administration route, use duration, and progestogen inclusion. The necessary pretreatment evaluation and appropriate follow-up recommendations were added for improved MHT standard care. The updated 2023 Clinical Practice Guideline on MHT is useful for gynecologists, general physicians, endocrinologists, and other healthcare professionals in treating menopausal women receiving hormone therapy in Thailand.

Skin Rejuvenation in Women using Menopausal Hormone Therapy: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the effect of menopausal hormone therapy (MHT) on skin aging in menopausal women.

METHODS

Studies were identified by searching PubMed, Cochrane Library, Google Scholar, and ClinicalTrials.gov databases using the key words "hormone replacement therapy" AND "skin" AND "menopausal." Studies that used and compared oral/transdermal MHT with placebo or another type of treatment in menopausal women aged 45-55 years were selected.

RESULTS

From 1,526 studies identified, 15 studies comprising 1,589 patients were included in the final analysis. Our meta-analysis aimed to compare skin elasticity (standard [Std] mean difference = 0.28; 95% confidence interval [CI], 0.03-0.54; P = 0.03), skin thickness (Std. mean difference = 1.27; 95% CI, 0.88-1.66; P < 0.00001), collagen content (Std. mean difference = 2.01; 95% CI, 1.42-2.61; P < 0.00001), and skin dryness (Std. mean difference = 0.15; 95% CI, -0.05 to 0.35; P = 0.14).

CONCLUSIONS

MHT increases elasticity and collagen content in the skin, thereby reducing the severity of wrinkles and increasing skin thickness. Nevertheless, more well-conducted clinical trials are required to answer all questions in an evidence-based manner.

Oral Supplementation and Systemic Drugs for Skin Aging: A Narrative Review

Skin aging is influenced by intrinsic and extrinsic factors and involves multiple pathogenic mechanisms. The most widely used treatments are topical products and minimally invasive procedures. Evidence on the benefits of systemic therapy is limited for several reasons: Reliance on mostly small and predominantly female samples, short study durations, methodologic heterogeneity, and a lack of consensus on which outcome measures are clinically relevant. Furthermore, systemic drugs and oral supplements are not without adverse effects. Oral hydrolyzed collagen and oral hyaluronic acid are well tolerated, and numerous clinical trials show they can mitigate some signs of skin aging. Low-dose oral isotretinoin is another option, but it has a higher risk of adverse effects. Evidence is lacking on the effects of the many dietary supplements on offer, such as vitamins, flavonoids, plant extracts, and trace elements. The future of skin aging management would appear to lie in the use of senolytic and senomorphic agents targeting senescent cells in the skin.

[Translated article] Oral Supplementation and Systemic Drugs for Skin Aging: A Narrative Review

Skin aging is influenced by intrinsic and extrinsic factors and involves multiple pathogenic mechanisms. The most widely used treatments are topical products and minimally invasive procedures. Evidence on the benefits of systemic therapy is limited for several reasons: reliance on mostly small and predominantly female samples, short study durations, methodologic heterogeneity, and a lack of consensus on which outcome measures are clinically relevant. Furthermore, systemic drugs and oral supplements are not without adverse effects. Oral hydrolyzed collagen and oral hyaluronic acid are well tolerated, and numerous clinical trials show they can mitigate some signs of skin aging. Low-dose oral isotretinoin is another option, but it has a higher risk of adverse effects. Evidence is lacking on the effects of the many dietary supplements on offer, such as vitamins, flavonoids, plant extracts, and trace elements. The future of skin aging management would appear to lie in the use of senolytic and senomorphic agents targeting senescent cells in the skin.

Menopause induces changes to the stratum corneum ceramide profile, which are prevented by hormone replacement therapy

The menopause can lead to epidermal changes that are alleviated by hormone replacement therapy (HRT). We hypothesise that these changes could relate to altered ceramide production, and that oestrogen may have a role in keratinocyte ceramide metabolism. White Caucasian women were recruited into three groups: pre-menopausal (n = 7), post-menopausal (n = 11) and post-menopausal taking HRT (n = 10). Blood samples were assessed for hormone levels, transepidermal water loss was measured to assess skin barrier function, and stratum corneum lipids were sampled from photoprotected buttock skin. Ceramides and sphingomyelins were analysed by ultraperformance liquid chromatography with electrospray ionisation and tandem mass spectrometry. Post-menopausal stratum corneum contained lower levels of ceramides, with shorter average length; changes that were not evident in the HRT group. Serum oestradiol correlated with ceramide abundance and length. Ceramides had shorter sphingoid bases, indicating altered de novo ceramide biosynthesis. Additionally, post-menopausal women had higher sphingomyelin levels, suggesting a possible effect on the hydrolysis pathway. Treatment of primary human keratinocytes with oestradiol (10 nM) increased production of CER[NS] and CER[NDS] ceramides, confirming an effect of oestrogen on cutaneous ceramide metabolism. Taken together, these data show perturbed stratum corneum lipids post-menopause, and a role for oestrogen in ceramide production.

Skin, hair and beyond: the impact of menopause

The skin is an endocrine organ and a major target of hormones such as estrogens, androgens and cortisol. Besides vasomotor symptoms (VMS), skin and hair symptoms often receive less attention than other menopausal symptoms despite having a significant negative effect on quality of life. Skin and mucosal menopausal symptoms include dryness and pruritus, thinning and atrophy, wrinkles and sagging, poor wound healing and reduced vascularity, whereas skin premalignant and malignant lesions and skin aging signs are almost exclusively caused by environmental factors, especially solar radiation. Hair menopausal symptoms include reduced hair growth and density on the scalp (diffuse effluvium due to follicular rarefication and/or androgenetic alopecia of female pattern), altered hair quality and structure, and increased unwanted hair growth on facial areas. Hormone replacement therapy (HRT) is not indicated for skin and hair symptoms alone due to the risk-benefit balance, but wider potential benefits of HRT (beyond estrogen's effect on VMS, bone, breast, heart and blood vessels) to include skin, hair and mucosal benefits should be discussed with women so that they will be able to make the best possible informed decisions on how to prevent or manage their menopausal symptoms.

Clinical and biological impact of the exposome on the skin

The skin exposome is defined as the totality of environmental exposures over the life course that can induce or modify various skin conditions. Here, we review the impact on the skin of solar exposure, air pollution, hormones, nutrition and psychological factors. Photoageing, photocarcinogenesis and pigmentary changes are well-established consequences of chronic exposure of the skin to solar radiation. Exposure to traffic-related air pollution contributes to skin ageing. Particulate matter and nitrogen dioxide cause skin pigmentation/lentigines, while ozone causes wrinkles and has an impact on atopic eczema. Human skin is a major target of hormones, and they exhibit a wide range of biological activities on the skin. Hormones decline with advancing age influencing skin ageing. Nutrition has an impact on numerous biochemical processes, including oxidation, inflammation and glycation, which may result in clinical effects, including modification of the course of skin ageing and photoageing. Stress and lack of sleep are known to contribute to a pro-inflammatory state, which, in turn, affects the integrity of extracellular matrix proteins, in particular collagen. Hormone dysregulation, malnutrition and stress may contribute to inflammatory skin disorders, such as atopic dermatitis, psoriasis, acne and rosacea.

Management of skin thinning and aging: review of therapies for neocollagenesis; hormones and energy devices

BACKGROUND

Hormone replacement therapy and various devices exist to treat signs of aging, such as skin thinning, yet there are no reviews summarizing or evaluating their role in neocollagenesis and the associated increase in skin thickness.

OBJECTIVE

To review the literature regarding stimulation and generation of new collagen in the dermis in two parts. Part 2 reviews oral and topical hormone replacement therapy as well as energy-based devices.

METHODS

The PubMed database was searched for related literature. Studies involving the use of hormone supplements and energy devices with a resultant change in collagen production or skin thickness were obtained and reviewed for evidence.

RESULTS

Hormones, including estrogen, testosterone, and dehydroepiandrosterone, and human growth hormone have been reported with substantiating evidence for neocollagenesis and dermal thickening. Energy devices, including radiofrequency, ultrasound, and laser therapy, have also been reported to stimulate neocollagenesis.

LIMITATIONS

The results presented in certain literature are not based on randomized controlled trials.

CONCLUSION

Hormone deficient individuals can regain skin thickness with hormone replacement therapy. Dermal heating can provide a substantial amount of neocollagenesis; however, laser technology, specifically CO₂ , appears to be the most effective at increasing skin collagen and tightening.

Impact of progesterone on skin and hair in menopause - a comprehensive review

In clinical practice, micronized progesterone (MP) is frequently recommended to treat signs and symptoms of skin and hair aging in menopausal women. The aim of this comprehensive review was to evaluate whether topically or systemically applied MP may effectively prevent or slow down signs of skin and hair aging. Three out of six identified studies reported an impact of MP on skin aging markers in menopausal women. Of these, two studies reported a benefit: one for topically applied MP, another for systemically applied combined menopausal hormone therapy (MHT) comprising MP as progestogen for endometrial protection. Tolerability and safety of MP were good. However, there was no study investigating the impact of MP on menopausal scalp hair. In conclusion, delay of skin aging comprises lifestyle adjustment, antioxidants, and several esthetic procedures. In menopausal women, MHT displays beneficial effects on skin aging. There is poor quality but promising scientific evidence for MP displaying anti-aging skin effects in menopausal women. However, good quality studies are needed.

The Skin Interactome: A Holistic "Genome-Microbiome-Exposome" Approach to Understand and Modulate Skin Health and Aging

Higher demands on skin care cosmetic products for strong performance drive intense research to understand the mechanisms of skin aging and design strategies to improve overall skin health. Today we know that our needs and influencers of skin health and skin aging change throughout our life journey due to both extrinsic factors, such as environmental factors and lifestyle factors, as well as our intrinsic factors. Furthermore, we need to consider our microflora, a collection of micro-organisms such as bacteria, viruses, and fungi, which is a living ecosystem in our gut and on our skin, that can have a major impact on our health. Here, we are viewing a holistic approach to understand the collective effect of the key influencers of skin health and skin aging both reviewing how each of them impact the skin, but more importantly to identify molecular conjunction pathways of these different factors in order to get a better understanding of the integrated “genome-microbiome-exposome” effect. For this purpose and in order to translate molecularly the impact of the key influencers of skin health and skin aging, we built a digital model based on system biology using different bioinformatics tools. This model is considering both the positive and negative impact of our genome (genes, age/gender), exposome: external (sun, pollution, climate) and lifestyle factors (sleep, stress, exercise, nutrition, skin care routine), as well as the role of our skin microbiome, and allowed us in a first application to evaluate the effect of the genome in the synthesis of collagen in the skin and the determination of a suitable target for boosting pro-collagen synthesis. In conclusion, we have, through our digital holistic approach, defined the skin interactome concept, as an advanced tool to better understand the molecular genesis of skin aging and further develop a strategy to balance the influence of the exposome and microbiome to protect, prevent, and delay the appearance of skin aging signs and preserve good skin health condition. In addition, this model will aid in identifying and optimizing skin treatment options based on external triggers, as well as helping to design optimal treatments modulating the intrinsic pathways.

Distribution of heparan sulfate correlated with the expression of heparanase-1 and matrix metalloproteinase-9 in an ovariectomized rats skin

There are few studies on heparan sulfate (HS) in the skin, during aging, when estrogen is suppressed. The enzyme heparanase-1 (HPSE-1), has its 17β-estrogen-regulated expression in pathological conditions such as cancer and chronic inflammatory diseases. HPSE-1 is correlated with the matrix metalloproteinase-9 (MMP-9), an endopeptidase that also undergoes estrogen action. We investigated the distribution of HS, expression HPSE-1 and MMP-9 in the skin of adult rats at different ages and in the age-matched ovariectomized rats to evaluate the influence of low estrogen on the distribution of HS. Thirty female Wistar rats were used. Rats underwent to a sham surgery (ctr, n = 15) or to a bilateral ovariectomy (ovx, n = 15) and were euthanized after 45, 75, and 90 days after ovariectomy. Morphological, morphometric, biochemical, and reverse transcriptase polymerase chain reaction (RT-PCR) methodologies were used. A significant decrease (P < 0.001) in total skin thickness was observed in the ctr and ovx animals, being higher in the older animals. The thickness of the epidermis and dermis decreased; however, the proportion in the total skin remained similar comparing ctr and ovx. An increase of HS with increasing age and ovariectomy was observed. The expression of the HPSE-1 and MMP-9 enzymes decreased, being higher in old animals. A correlation between the increase of HS and the decrease of the HPSE-1 was demonstrated in both groups. Overall, these data suggested that estrogen acts in the regulation of the expression of the HPSE-1, not only in pathological states, as already established, but also in aging.

The role of bioidentical hormone replacement therapy in anti-aging medicine: a review of the literature

The changes in skin and overall appearance that occur with increasing age can be partly attributed to declining hormone levels. While hormonal deficiencies are most commonly associated with postmenopausal females, males are also subject to age-related testosterone decline and may benefit from replacement of deficient hormones. However, great disparities exist between the recommendations of scientific societies and actual use of hormone supplements in aging patients. The purpose of this literature review is to discuss the role of hormones in the aging process of the skin, explain the safety profile of hormone replacement therapy, specifically discussing the superiority of bioidentical hormones, and highlight the benefits of hormone replacement in anti-aging of the skin. In summary, this literature review suggests that hormone replacement with bioidentical hormones is a safe and effective way to prevent skin aging.

A Holistic Approach to Antiaging as an Adjunct to Antiaging Procedures: A Review of the Literature

BACKGROUND

Aging is a multifactorial process and depends on both intrinsic and extrinsic factors. Procedural options for diminishing signs of intrinsic aging and cosmetic rejuvenation have expanded dramatically. However, less attention is paid to counseling patients on options for mitigating extrinsic factors related to aging.

OBJECTIVE

The objective of this study was to review changes that occur with intrinsic and extrinsic aging, and provide evidence-based holistic counseling recommendations that can be used synergistically with aesthetic procedures to maximize antiaging interventions.

MATERIALS AND METHODS

A PubMed search was conducted for articles on intrinsic and extrinsic aging as it relates to skin, fat, muscle, and bone. Key clinical trials and studies on the effect of diet, hormones, exercise, sleep, stress, dental hygiene, smoking, pollution, and oxidative stress on the aging process are reviewed, and treatment recommendations are summarized based on available evidence.

RESULTS

Conventional cosmetic procedures and cosmeceuticals work together with nutritious diet, exercise, dental hygiene, hormonal balance, stress reduction, smoking and pollution avoidance, and healthy sleep patterns for a better effect on antiaging.

CONCLUSION

A combination approach of multiple nonsurgical modalities along with healthy lifestyle recommendations to minimize intrinsic and extrinsic aging factors allows cosmetic practitioners to target multiple facets of aging concurrently and maximize the aesthetic interventions cosmetic dermatologists/practitioners provide.

Effect of β-agonist on the dexamethasone-induced expression of aromatase by the human monocyte cells

Emerging evidence suggests that sex steroids are important for human skin health. In particular, estrogen improves skin thickness, elasticity and moisture of older women. The major source of circulating estrogen is the ovary; however, local estrogen synthesis and secretion have important roles in, for example, bone metabolism and breast cancer development. We hypothesized that infiltrated peripheral monocytes are one of the sources of estrogen in skin tissues. We also hypothesized that, during atopic dermatitis under stress, a decline in the hypothalamus-pituitary-adrenal axis (HPA) and facilitation of the (hypothalamus)-sympathetic-adrenomedullary system (SAM) attenuates estrogen secretion from monocytes. Based on this hypothesis, we tested aromatase expression in the human peripheral monocyte-derived cell line THP-1 in response to the synthetic glucocorticoid dexamethasone (Dex), the synthetic β-agonist isoproterenol (Iso) and the β-antagonist propranolol (Pro). Dex mimics glucocorticoid secreted during excitation of the HPA, and Iso mimics catecholamine secreted during excitation of the SAM. We found that aromatase activity and the CYP19A1 gene transcript were both upregulated in THP-1 cells in the presence of Dex. Addition of Iso induced their downregulation and further addition of Pro rescued aromatase expression. These results may suggest that attenuation of estrogen secretion from peripheral monocytes could be a part of the pathology of stress-caused deterioration of atopic dermatitis. Further examination using an in vitro human skin model including THP-1 cells might be a valuable tool for investigating the therapeutic efficacy and mechanism of estrogen treatment for skin health.

Biomarkers of skin aging

Aging is a complex process not only influenced by inherited but also by several environmental factors. It is characterized by a progressive loss of function in multiple tissues, which leads to an increased probability of death. On the other hand, several morphological and histological changes are registered in aged skin that is mostly dependent on the cumulative exposure in environmental aging promoters, such as ultraviolet radiation. Understanding of individual pathogenesis and introduction of preventive measurements require objective assessment, i.e., the administration of biomarkers. Because of the complexity of skin aging, the exact definition of biomarkers is a major research challenge. In this article, we summarize the basic knowledge involving skin aging and its biomarkers.

Chronic UVB-irradiation actuates perpetuated dermal matrix remodeling in female mice: Protective role of estrogen

Chronic UVB-exposure and declined estradiol production after menopause represent important factors leading to extrinsic and intrinsic aging, respectively. Remodeling of the extracellular matrix (ECM) plays a crucial role in both responses. Whether the dermal ECM is able to recover after cessation of UVB-irradiation in dependence of estradiol is not known, however of relevance when regarding possible treatment options. Therefore, the endogenous sex hormone production was depleted by ovariectomy in female mice. Half of the mice received estradiol substitution. Mice were UVB-irradiated for 20 weeks and afterwards kept for 10 weeks without irradiation. The collagen-, hyaluronan- and proteoglycan- (versican, biglycan, lumican) matrix, collagen cleavage products and functional skin parameters were analyzed. The intrinsic aging process was characterized by increased collagen fragmentation and accumulation of biglycan. Chronic UVB-irradiation additionally augmented the lumican, versican and hyaluronan content of the dermis. In the absence of further UVB-irradiation the degradation of collagen and accumulation of biglycan in the extrinsically aged group was perpetuated in an excessive matter. Whereas estradiol increased the proteoglycan content, it reversed the effects of the perpetuated extrinsic response on collagen degradation. Suspension of the intrinsic pathway might therefore be sufficient to antagonize UVB-evoked long-term damage to the dermal ECM.

The effect of dietary and/or cosmetic argan oil on postmenopausal skin elasticity

Background

During menopause, the decrease of estrogenic secretion induces the disruption of skin functioning, thus causing the decline in skin elasticity characteristic of skin aging. The purpose of this study was to evaluate in postmenopausal women the effect of daily consumption and/or application of argan oil on skin elasticity.

Materials and methods

Sixty postmenopausal women consumed butter during the stabilization period and were randomly divided into two groups for the intervention period: the treatment group of 30 participants received dietary argan oil, the control group of 30 participants received olive oil, and both groups applied cosmetic argan oil in the left volar forearm during a 60-day period. Assessments of skin elasticity parameters, ie, the three R-parameters (R2 or gross-elasticity of the skin, R5 or net elasticity of the skin, and R7 or biological elasticity), and the resonance running time (RRT) at both volar forearms of the two groups were performed during three visits: before starting oils consumption and application, after 30 days of oils consumption and application, and after 60 days of oils consumption and application.

Results

The consumption of argan oil led to a significant increase of gross-elasticity of the skin (R2) (P<0.001), net elasticity of the skin (R5) (P<0.001), biological elasticity (R7) (P<0.001), and a significant decrease of RRT (P=0.002). The application of argan oil led to a significant increase of gross-elasticity of the skin (R2) (P<0.001), net elasticity of the skin (R5) (P<0.001), biological elasticity (R7) (P=0.001), and a significant decrease of RRT (P<0.001).

Conclusion

Our findings suggest that the daily consumption and/or topical application of argan oil have an anti-aging effect on the skin demonstrated by the improvement of skin elasticity, characterized by an increase of R-parameters (R2, R5, and R7) and a decrease of RRT.

Stem cells and aberrant signaling of molecular systems in skin aging

The skin is the body's largest organ and it is able to self-repair throughout an individual's life. With advanced age, skin is prone to degenerate in response to damage. Although cosmetic surgery has been widely adopted to rejuvinate skin, we are far from a clear understanding of the mechanisms responsible for skin aging. Recently, adult skin-resident stem/progenitor cells, growth arrest, senescence or apoptotic death and dysfunction caused by alterations in key signaling genes, such as Ras/Raf/MEK/ERK, PI3K/Akt-kinases, Wnt, p21 and p53, have been shown to play a vital role in skin regeneration. Simultaneously, enhanced telomere attrition, hormone exhaustion, oxidative stress, genetic events and ultraviolet radiation exposure that result in severe DNA damage, genomic instability and epigenetic mutations also contribute to skin aging. Therefore, cell replacement and targeting of the molecular systems found in skin hold great promise for controlling or even curing skin aging.

Anti-aging cosmetics: facts and controversies

The authors review ageing in its extrinsic and intrinsic mechanisms, as well as the therapies available for improving its effects, and present some of the facts and controversies related to anti-aging cosmetics.

Oral estradiol and dydrogesterone combination therapy in postmenopausal women: review of efficacy and safety

HRT is known to be effective for the relief of menopausal symptoms and prevention of osteoporosis. HRT should be tailored to the woman, enhancing the beneficial effects of the treatment while minimizing the risks. It is difficult to evaluate data on particular preparations of HRT and the different dosages in isolation. The purpose of this review is to highlight the efficacy and safety specific to oral estradiol and dydrogesterone combinations of four different dose strengths. A systematic literature search using Medline was carried out to identify studies containing efficacy or safety data. The findings of the retrieved publications confirm that estradiol and dydrogesterone combinations give very effective menopausal symptom relief and prevention of osteoporosis whilst maintaining a good safety profile. Data also show that these combinations of HRT give additional benefit to certain metabolic parameters including lipids, insulin, glucose and body fat distribution. By selecting the treatment and dose most suitable for each individual woman at her particular stage of menopause, the benefits can be optimized whilst mitigating the risks. HRT plays an important role in improving and maintaining women's health when used appropriately.

17β-estradiol protects human skin fibroblasts and keratinocytes against oxidative damage

BACKGROUND

Reactive oxygen species (ROS) cause severe damage to extracellular matrix and to molecular structure of DNA, proteins and lipids. Accumulation of these molecular changes apparently constitutes the basis of cell ageing. 17b-estradiol (E2) has a key role in skin ageing homeostasis as evidenced by the accelerated decline in skin appearance seen in the perimenopausal years. Oestrogens improve many aspects of the skin such as skin thickness, vascularization, collagen content and quality. Despite these clinical evidences, the effects of oestrogens on skin at the cellular level need further clarification.

MATERIALS AND METHODS

HaCaT and human fibroblasts were cultured under various conditions with E2 and H2 O2 ; then were subjected to immunofluorescence and western blot analysis. Lipoperoxidation was investigated using BODIPY.

RESULTS

In human fibroblasts oxidative stress decreases procollagen-I synthesis, while E2 significantly increases it. Fibroblasts and HaCaT cells viability in the presence of E2 demonstrates a notably increased resistance to H2 O2 effects. Furthermore E2 is able to counteract H2 O2 -mediated lipoperoxidation and DNA oxidative damage in skin cells.

DISCUSSION

In this study we highlight that the menopause-associated oestrogens decline is involved in reduced collagen production and that E2 could counteract the detrimental effects of oxidative stress on the dermal compartment during skin aging. Furthermore, our data show that physiological concentrations of oestrogens are able to interfere with ROS-mediated cell viability reduction and to protect human skin cells against oxidative damage to cellular membranes and nucleic acids structure.

CONCLUSION

Our experimental data show that the presence of 17β-estradiol may protect skin cells against oxidative damage and that the dramatic lowering of oestrogen levels during menopause, could render skin more susceptible to oxidative damage.

Hormonal therapy of intrinsic aging

Intrinsic skin aging represents the biological clock of the skin cells per se and reflects the reduction processes that are common in internal organs. The reduced secretion of the pituitary, adrenal glands, and the gonads contributes to characteristic aging-associated body and skin phenotypes as well as behavior patterns. Our knowledge of whether there is a direct or indirect connection between hormonal deficiency and skin aging still remains limited. In females, serum levels of 17β-estradiol, dehydroepiandrosterone, progesterone, growth hormone (GH), and its downstream hormone insulin-like growth factor I (IGF-I) are significantly decreased with increasing age. In males, serum levels of GH and IGF-I decrease significantly, whereas it can decrease in late age in a part of the population. Hormones have been shown to influence skin morphology and functions, skin permeability, wound healing, sebaceous lipogenesis, and the metabolism of skin cells. Prevention of skin aging by estrogen/progesterone replacement therapy is effective if administered early after menopause and influences intrinsically aged skin only. Vitamin D substitution and antioxidant treatment may also be beneficial. Replacement therapy with androgens, GH, IGF-I, progesterone, melatonin, cortisol, and thyroid hormones still remains controversial.

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

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

Royal jelly increases collagen production in rat skin after ovariectomy

Royal jelly (RJ) is a honeybee product that contains proteins, carbohydrates, fats, free amino acids, vitamins, and minerals. RJ has been reported to have antitumor, antibacterial, and wound-healing activities. We previously reported that RJ enhanced the migration of human dermal fibroblasts and altered the levels of cholesterol and sphinganine in an in vitro wound-healing model in addition to regulating skin photoaging following exposure to ultraviolet-B radiation. We established an animal model of skin aging in the context of estrogen deficiency and assessed the antiaging effects of RJ on skin. To establish an in vivo model of skin aging, bilateral ovariectomies were performed in 12-week-old virgin female Sprague-Dawley rats. Induction of osteoporosis was confirmed through two-dimensional images of the trabecular bone in the left femoral necks using microcomputed tomography. The protective effects of RJ ovariectomy-induced skin aging were examined by determining the protein expression of type I procollagen and matrix metalloproteinase (MMP)-1. The collagen content and epidermal thickness of skin tissue were measured by staining techniques. There was a significant difference in weight between sham-operated and ovariectomized groups. Food efficiency ratio did not differ significantly among the groups. The level of procollagen type I protein was increased in the dorsal skin of ovariectomized rats fed with a dietary supplement containing 1% RJ extract, but the level of MMP-1 was not altered. In particular, the amount of collagen recovered was close to the normal level. RJ may protect against skin aging by enhancing collagen production in rats with ovariectomy-induced estrogen deficiency.

Estrogen and skin: therapeutic options

Aging of the skin is associated with skin thinning, atrophy, dryness, wrinkling, and delayed wound healing. These undesirable aging effects are exacerbated by declining estrogen levels in postmenopausal women. With the rise in interest in long-term postmenopausal skin management, studies on the restorative benefits that estrogen may have on aged skin have expanded. Systemic estrogen replacement therapy (ERT) has been shown to improve some aspects of skin. Estrogen restores skin thickness by increasing collagen synthesis while limiting excessive collagen degradation. Wrinkling is improved following estrogen treatment since estrogen enhances the morphology and synthesis of elastic fibers, collagen type III, and hyaluronic acids. Dryness is also alleviated through increased water-holding capacity, increased sebum production, and improved barrier function of the skin. Furthermore, estrogen modulates local inflammation, granulation, re-epithelialization, and possibly wound contraction, which collectively accelerates wound healing at the expense of forming lower quality scars. Despite its promises, long-term ERT has been associated with harmful systemic effects. In the search for safe and effective alternatives with more focused effects on the skin, topical estrogens, phytoestrogens, and tissue-specific drugs called selective estrogen receptor modulators (SERMs) have been explored. We discuss the promises and challenges of utilizing topical estrogens, SERMs, and phytoestrogens in postmenopausal skin management.

Clinical aspects and molecular diagnostics of skin aging

This contribution will address the effect of aging on skin functions, with a particular focus on skin permeability, wound healing, angiogenesis, lipogenesis, sweat production, immune function, and vitamin D synthesis. With accelerating age, skin functions deteriorate due to structural and morphologic changes. Skin is prone to the development of several diseases, varying from benign to malignant. Because the number of persons aged 80 and older is expected to rise in the next decades, disease prevention will become an important issue. Screening examinations and prevention through public education starting at an early age regarding sun avoidance, the use of sunscreens and the importance of a balanced nutrition are the first steps for successful healthy aging. Although the fundamental mechanisms in the pathogenesis of aged skin are still poorly understood, a growing body of evidence points toward the involvement of multiple pathways. Recent data obtained by expression profiling studies and studies of progeroid syndromes illustrate that among the most important biologic processes involved in skin aging are alterations in DNA repair and stability, mitochondrial function, cell cycle and apoptosis, extracellular matrix, lipid synthesis, ubiquitin-induced proteolysis and cellular metabolism. Among others, a major factor that has been implicated in the initiation of aging is the physiologic decline of hormones occurring with age. However, hormones at age-specific levels may regulate not only age-associated mechanisms but also tumor suppressor pathways that influence carcinogenesis. Understanding the molecular mechanisms of aging may open new strategies to deal with the various diseases accompanying high age, including cancer.

Characterization of skin friction coefficient, and relationship to stratum corneum hydration in a normal Chinese population

BACKGROUND AND OBJECTIVES

Studies have demonstrated that some cutaneous biophysical properties vary with age, gender and body sites. However, the characteristics of the skin friction coefficient in different genders and age groups have not yet been well established. In the present study, we assess the skin friction coefficient in a larger Chinese population.

METHODS

A total of 633 subjects (300 males and 333 females) aged 0.15-79 years were enrolled. A Frictiometer FR 770 and Corneometer CM 825 (C&K MPA 5) were used to measure the skin friction coefficient and stratum corneum hydration, respectively, on the dorsal surface of the hand, the forehead and the canthus.

RESULTS

In the females, the maximum skin friction coefficients on both the canthus and the dorsal hand skin were observed around the age of 40 years. In the males, the skin friction coefficient on the dorsal hand skin gradually increased from 0 to 40 years of age, and changed little afterward. Skin friction coefficients on some body sites were higher in females than in age-matched males in some age groups. On the canthus and the dorsal hand skin of females, a positive correlation was found between skin friction coefficient and stratum corneum hydration (p < 0.001 and p < 0.0001, respectively). In contrast, in males, the skin friction coefficient was positively correlated with stratum corneum hydration on the forehead and the dorsal hand skin (p < 0.05 and p < 0.0001, respectively).

CONCLUSION

The skin friction coefficient varies with age, gender and body site, and positively correlates with stratum corneum hydration on some body sites.

[Dermatoendocrinology. Skin aging]

Hormones and their imbalances have significant effects on the morphology and physiology of the skin and influence various skin functions, especially wound healing and lipogenesis. With increasing age, the concentrations of important circulating hormones, including growth hormone and sex-related steroids, decrease continuously. As a result, physiologic processes are negatively influenced and various age-associated disorders may develop. As the population aged 80 and over is expected to rise in the next decades, the understanding of the molecular mechanisms accompanying skin aging and disease prevention will become even more important and play a role in preventing disease.

[Skin aging]

Like the entire human organism, the skin is subject to an intrinsic unpreventable aging process. But exogenous factors also influence skin aging. Ultraviolet radiation in particular results in premature skin aging, also referred to as extrinsic skin aging or photo aging, causing in large part aging-associated changes in sun-exposed areas. Intrinsic and extrinsic aging share several molecular similarities despite morphological and pathophysiological differences. The formation of reactive oxygen species and the induction of metalloproteinases reflect central aspects of skin aging. Accumulation of fragmented collagen fibrils prevents neocollagenesis and accounts for further degradation of extracellular matrix by means of positive feedback regulation. The importance of extrinsic factors in skin aging and the detection of its mechanisms has given rise to development of various therapeutic and preventive strategies.

Variation of skin surface pH, sebum content and stratum corneum hydration with age and gender in a large Chinese population

BACKGROUND AND OBJECTIVES

Evidence suggests the importance of skin biophysical properties in predicting diseases and in developing appropriate skin care. The results to date of studies on skin surface pH, stratum corneum (SC) hydration and sebum content in both genders and at various ages have been inconclusive, which was in part due to small sample size. Additionally, little is known about the skin physical properties of Asian, especially Chinese, subjects. In the present study, we assess the difference in skin surface pH, sebum content and SC hydration at various ages and in both genders in a large Chinese population without skin diseases.

METHODS

713 subjects (328 males and 385 females) aged 0.5-94 years were enrolled in this study. The subjects were divided by age into 5 groups, i.e., 0-12, 13-35, 36-50, 51-70 and over 70 years old. A multifunctional skin physiology monitor was used to measure SC hydration, skin surface pH and sebum content on both the forehead and the forearms.

RESULTS

In males, the highest sebum content was found on the forearm and the forehead in the age groups 36-50 (93.47 +/- 10.01 microg/cm(2)) and 51-70 years (9.16 +/- 1.95 microg/cm(2)), while in females, the highest sebum content was found on the forearm and the forehead in the age groups 13-35 (61.91 +/- 6.12 microg/cm(2)) and 51-70 years (7.54 +/- 2.55 microg/cm(2)). The forehead sebum content was higher in males aged 13-70 years than in age-matched females; the sebum content on the forehead in both males and females was higher than that on the forearm. Skin surface pH on the forehead of both males and females over the age of 70 years was higher than that in younger groups. SC hydration on the forehead in both males and females was lower above the age of 70, and the one in males aged 13-35 was higher than that in females (43.99 +/- 1.88 vs. 36.38 +/- 1.67 AU, p < 0.01). SC hydration on the forehead in both males and females did not significantly differ from that on the forearm.

CONCLUSIONS

In a large Chinese cohort, the skin surface pH, sebum content and SC hydration vary with age, gender and body site.

Effects of topical DHEA on aging skin: a pilot study

OBJECTIVES

Dehydroepiandrosterone (DHEA) is a steroid hormone involved in physiological aging. When administered by oral route, it has been shown to positively affect skin condition on aged people. The purpose of this pilot study was to observe the in vivo effects on skin aging of topical DHEA (1%).

METHODS

The DHEA formulation (1%) or the vehicle was topically applied for 4 months to facial and hand skin, in two groups of 20 post-menopausal women. The efficacy of the treatment was evaluated on the basis of clinical and biophysical signs linked to skin aging.

RESULTS

We showed that DHEA treatment increased the rate of sebum, which was perceived rather positively by a menopausal population usually affected with a declining sebum level. Topical DHEA tends to improve skin brightness, to counteract papery appearance of skin and epidermal atrophy, a characteristic feature of hormone-related skin aging. Topical DHEA could also act on skin process related to wrinkles, but this result remains to be confirmed.

CONCLUSIONS

This pilot study showed beneficial effects on skin characteristics that are rarely provided by topical treatments. It raised some interesting clues towards the treatment of skin aging.