Androgens affect the activity of human sebocytes in culture in a manner dependent on the localization of the sebaceous glands and their effect is antagonized by spironolactone

Effects of spironolactone on skin biophysical properties in women with acne treated with oral spironolactone

BACKGROUND

Spironolactone (SPL) is an effective treatment for women acne, but other effects on skin biophysical properties remain to be investigated.

OBJECTIVES

The aim of the current study was to explore the effects of oral SPL used to treat women acne on skin biophysical properties, including hydration, transepidermal water loss (TEWL), skin surface lipid (SSL) levels, mechanical properties, color, pH, and pore size.

MATERIALS AND METHODS

Twenty-five Thai women with acne treated with oral SPL were followed for 6 months. Skin hydration, TEWL, SSL levels, mechanical properties, color, pH, and pore size of the forehead, chest, and inner arm were evaluated at baseline and 2, 4, and 6 months after treatment with oral SPL. Facial and upper back pore size were also assessed. Clinical outcomes were changes in these skin biophysical properties at each visit compared with baseline.

RESULTS

Skin hydration, TEWL, SSL levels, color, pH, and pore size remained stable throughout the study. Facial skin parameters at 6 months demonstrated the following changes: hydration levels, 7.60 (95% confidence interval [CI], -59.74 to 74.94); TEWL, -2.36 (95% CI, -5.77 to 1.06); L* value, 0.51 (95% CI, -0.70 to 1.72); individual typology angle, 1.65 (95% CI -2.27 to 5.57); pH, 0.01 (95% CI -0.43 to 0.46); pore size, -0.24 (95% CI, -1.21 to 0.73); and SSL levels, 7.60 (95% CI -59.74 to 74.94). Improvement of facial mechanical properties was observed. R0 (indicating skin tightness) and R1 (indicating elasticity) showed significant decreases (-0.076 [95% CI, -0.141 to -0.010] and -0.016 [95% CI, -0.033 to -0.001]). R3 and R4 (representing tiring effects) were also improved (-0.091 [95% CI, -0.158 to -0.025] and -0.022 [95% CI, -0.044 to -0.001]). Parameters in the truncal and inner arm areas remained stable, except for skin elasticity and tiring effects, which exhibited a similar trend of improvement as the facial area. The changes were notable as early as 4 months.

CONCLUSION

Oral SPL used for acne did not impair the skin barrier. Moreover, the skin mechanical properties were improved at 4 to 6 months.

Guidelines of care for the management of acne vulgaris

BACKGROUND

Acne vulgaris commonly affects adults, adolescents, and preadolescents aged 9 years or older.

OBJECTIVE

The objective of this study was to provide evidence-based recommendations for the management of acne.

METHODS

A work group conducted a systematic review and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach for assessing the certainty of evidence and formulating and grading recommendations.

RESULTS

This guideline presents 18 evidence-based recommendations and 5 good practice statements. Strong recommendations are made for benzoyl peroxide, topical retinoids, topical antibiotics, and oral doxycycline. Oral isotretinoin is strongly recommended for acne that is severe, causing psychosocial burden or scarring, or failing standard oral or topical therapy. Conditional recommendations are made for topical clascoterone, salicylic acid, and azelaic acid, as well as for oral minocycline, sarecycline, combined oral contraceptive pills, and spironolactone. Combining topical therapies with multiple mechanisms of action, limiting systemic antibiotic use, combining systemic antibiotics with topical therapies, and adding intralesional corticosteroid injections for larger acne lesions are recommended as good practice statements.

LIMITATIONS

Analysis is based on the best available evidence at the time of the systematic review.

CONCLUSIONS

These guidelines provide evidence-based recommendations for the management of acne vulgaris.

Beneficial Extracardiac Effects of Cardiovascular Medications

Cardiovascular diseases are the most common cause of death worldwide, with cardiovascular medications being amongst the most common medications prescribed. These medications have diverse effects on the heart, vascular system, as well as other tissues and organ systems. The extra cardiovascular effects have been found to be of use in the treatment of non-cardiovascular diseases and pathologies. Minoxidil is used to manage systemic hypertension with its well-known side effect of hirsutism used to treat alopecia and baldness. Sildenafil was originally investigated as a treatment option for systemic hypertension; however, its side effect of penile erection led to it being widely used for erectile dysfunction. Alpha-1 blockers such as terazosin are indicated to treat systemic hypertension but are more commonly used for benign prostatic hyperplasia and post-traumatic stress disorder. Beta blockers are the mainstay treatment for congestive heart failure and systemic hypertension but have been found useful to help in patients with intention tremors as well as prophylaxis of migraines. Similarly, calcium channel blockers are indicated in medical expulsion therapy for ureteric calculi in addition to their cardiovascular indications. Thiazides are commonly used for treating systemic hypertension and as diuretics. Thiazides can cause hypocalciuria and hypercalcemia. This side effect has led to thiazides being used to treat idiopathic hypercalciuria and associated nephrolithiasis. Spironolactone is commonly utilized in treating heart failure and as a diuretic for edema. It's well described anti-androgen side effects have been used for acne vulgaris and hirsutism in polycystic ovarian syndrome. This review article discusses how the various extracardiovascular effects of commonly used cardiovascular medications are put to use in managing non-cardiovascular conditions.

An appraisal of laboratory models of androgenetic alopecia: A systematic review

Background

Androgenetic alopecia (AGA) is the most common form of non‐scarring alopecia in humans. Several studies have used different laboratory models to study the pathogenesis and interventions for AGA. These study models have proved beneficial and have led to the approval of two drugs. However, the need to build on existing knowledge remains by examining the relevance of study models to the disease.

Objective

We sought to appraise laboratory or pre‐clinical models of AGA.

Method

We searched through databases (PubMed, ScienceDirect, Web of Science, World CAT, Scopus and Google Scholar) for articles on AGA‐related studies from 1942 to March 2019 with a focus on study models.

Results

The search rendered 101 studies after screening and deduplication. Several studies (70) used in vitro models, mostly consisting of two‐dimensional monolayer cells for experiments involving the characterization of androgen and 5‐alpha reductase (5AR) and inhibition thereof, the effects of dihydrotestosterone (DHT) and biomarker(s) of AGA. Twenty‐seven studies used in vivo models of mice and monkeys to investigate DHT synthesis, the expression and inhibition of 5AR and hair growth. Only four studies used AGA‐related or healthy excisional/punch biopsy explants as ex vivo models to study the action of 5AR inhibitors and AGA‐associated genes. No study used three‐dimensional [3‐D] organoids or organotypic human skin culture models.

Conclusion

We recommend clinically relevant laboratory models like human or patient‐derived 3‐D organoids or organotypic skin in AGA‐related studies. These models are closer to human scalp tissue and minimize the use of laboratory animals and could ultimately facilitate novel therapeutics.

Contribution of GATA6 to homeostasis of the human upper pilosebaceous unit and acne pathogenesis

Although acne is the most common human inflammatory skin disease, its pathogenic mechanisms remain incompletely understood. Here we show that GATA6, which is expressed in the upper pilosebaceous unit of normal human skin, is down-regulated in acne. GATA6 controls keratinocyte proliferation and differentiation to prevent hyperkeratinisation of the infundibulum, which is the primary pathological event in acne. When overexpressed in immortalised human sebocytes, GATA6 triggers a junctional zone and sebaceous differentiation program whilst limiting lipid production and cell proliferation. It modulates the immunological repertoire of sebocytes, notably by upregulating PD-L1 and IL10. GATA6 expression contributes to the therapeutic effect of retinoic acid, the main treatment for acne. In a human sebaceous organoid model GATA6-mediated down-regulation of the infundibular differentiation program is mediated by induction of TGFβ signalling. We conclude that GATA6 is involved in regulation of the upper pilosebaceous unit and may be an actionable target in the treatment of acne.

Assessing Biophysical and Physiological Profiles of Scalp Seborrheic Dermatitis in the Thai Population

Background

Scalp seborrheic dermatitis (SD) is a common and chronic inflammatory skin disease which tends to recur over time. By measuring biophysical properties of the stratum corneum, many studies report abnormal biophysical profiles and their association in various dermatologic diseases. The aim of the study is to analyze the biophysical properties and skin barrier defects of scalp SD compared to healthy controls.

Materials and Methods

This study is a cross-sectional study assessing the correlation of various biophysical and physiological profiles in scalp SD. Forty-two Thai participants with scalp SD were enrolled in the study and 40 healthy participants were also enrolled as the control group. Both SD and control group were subjected to a one-time biophysical and physiological properties' measurement of transepidermal water loss (TEWL), stratum corneum hydration (SCH), skin surface pH, skin surface lipid, and skin roughness.

Results

The mean TEWL of lesional skin of SD cases were significantly higher than those of control group (P<0.05). Relating to high mean TEWL, the mean SCH was found to be significantly lower in SD cases (P<0.05). Skin surface lipid was also found to be significantly higher in SD group (P<0.05). However, there were no differences in skin surface pH (P=0.104) and roughness (P=0.308) between the two groups. Pairwise comparison of each subgroup found that moderate and severe SD demonstrated significantly higher mean skin surface lipid than that of control group (P<0.05).

Conclusion

Scalp SD may be associated with seborrhea in Thai population. Monitoring of SCH, TEWL, and skin surface lipid could be helpful in assessing severity and evaluating the treatment outcome in patients with scalp SD.

From pathogenesis of acne vulgaris to anti-acne agents

Acne vulgaris is a cutaneous chronic inflammatory disorder with complex pathogenesis. Four factors play vital roles in acne pathophysiology: hyperseborrhea and dysseborrhea, altered keratinization of the pilosebaceous duct, Cutibacterium acnes (C. acnes) and inflammation. The main hormones responsible for the development of acne vulgaris include androgens, insulin and insulin-like growth factor-1. Other factors involved in this process are corticotropin-releasing hormone, α-melanocyte-stimulating hormone and substance P. Wnt/β-catenin signaling pathway, phosphoinositide 3-kinase (PI3K)/Akt pathway, mitogen-activated protein kinase pathway, adenosine 5'-monophosphate-activated protein kinase pathway and nuclear factor kappa B pathway participate in the modulation of sebocyte, keratinocyte and inflammatory cell (e.g. lymphocytes, monocytes, macrophages, neutrophils) activity. Among all the triggers and pathways mentioned above, IGF-1-induced PI3K/Akt/Forkhead box protein O1/mammalian target of rapamycin (mTOR) C1 pathway is the most important signaling responsible for acne pathogenesis. Commonly used anti-acne agents include retinoids, benzoyl peroxide, antibiotics and hormonal agents (e.g. spironolactone, combination oral contraceptive and flutamide). New approaches including peroxisome proliferator-activated receptor γ modifier, melanocortin receptor antagonists, epigallocatechin-3-gallate, metformin, olumacostat glasaretil, stearoyl-CoA desaturase inhibitor omiganan pentahydrochloride, K_DPT, afamelanotide, apremilast and biologics have been developed as promising treatments for acne vulgaris. Although these anti-acne agents have various pharmacological effects against the diverse pathogenesis of acne, all of them have a synergistic mode of action, the attenuation of Akt/mTORC1 signaling and enhancement of p53 signal transduction. In addition to drug therapy, diet with no hyperglycemic carbohydrates, no milk and dairy products is also beneficial for treatment of acne.

Recent advances in the endocrinology of the sebaceous gland

The sebaceous gland, long considered an evolutionary relic with little-to-no physiological relevance in humans, has emerged in recent decades as a key orchestrator and contributor to many cutaneous functions. In addition to the classical physico-chemical barrier function of the skin against constant environmental challenges, a more novel, neuro-immune modulatory role has also emerged. As part of the complex intercellular communication network of the integumentary system, the sebaceous gland acts as a “relay station” in the skin for many endocrine factors. This review aims to offer a comprehensive overview of endocrine effects and subsequent interactions on this much maligned mini-organ.

TFOS DEWS II Sex, Gender, and Hormones Report

One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs). In addition to sex, gender also appears to be a risk factor for DED. "Gender" and "sex" are words that are often used interchangeably, but they have distinct meanings. "Gender" refers to a person's self-representation as a man or woman, whereas "sex" distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health. Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.

Spironolactone for the treatment of acne in women, a retrospective study of 110 patients

BACKGROUND

There is limited evidence on the safety and efficacy of spironolactone in the treatment of women with acne. Thus, for many dermatologists spironolactone remains an alternative rather than a mainstay treatment for female patients with acne.

METHODS

An electronic medical records search tool was used to select data from a group of women who received spironolactone to treat acne and were evaluated with the comprehensive acne severity scale (CASS) before treatment and at all follow-up visits. Data points were collected for CASS scores at each follow-up visit, concurrent and previous treatments, and side effects. These data points were used to draw conclusions about the safety and efficacy of spironolactone in this patient population.

RESULTS

There were 110 patients that met all eligibility requirements. Of these, 94 patients saw an improvement in their CASS score and 61 patients completely cleared their score to 0. There were 16 patients who did not improve and six who relapsed after initial improvement. The women saw an average improvement in their acne by 73.1% for the face, 75.9% for the chest, and 77.6% for the back. Fifty-one women experienced side effects, but only six found them bothersome enough to stop taking spironolactone.

CONCLUSION

A majority of women in this study saw a dramatic improvement in their acne while treated with spironolactone. There were low rates of relapse or discontinuation of the medication. To further promote the use of spironolactone as a first-line systemic treatment for women with acne, there must be more prospective controlled trials.

Guidelines of care for the management of acne vulgaris

Acne is one of the most common disorders treated by dermatologists and other health care providers. While it most often affects adolescents, it is not uncommon in adults and can also be seen in children. This evidence-based guideline addresses important clinical questions that arise in its management. Issues from grading of acne to the topical and systemic management of the disease are reviewed. Suggestions on use are provided based on available evidence.

Seborrheic Dermatitis and Dandruff: A Comprehensive Review

Seborrheic Dermatitis (SD) and dandruff are of a continuous spectrum of the same disease that affects the seborrheic areas of the body. Dandruff is restricted to the scalp, and involves itchy, flaking skin without visible inflammation. SD can affect the scalp as well as other seborrheic areas, and involves itchy and flaking or scaling skin, inflammation and pruritus. Various intrinsic and environmental factors, such as sebaceous secretions, skin surface fungal colonization, individual susceptibility, and interactions between these factors, all contribute to the pathogenesis of SD and dandruff. In this review, we summarize the current knowledge on SD and dandruff, including epidemiology, burden of disease, clinical presentations and diagnosis, treatment, genetic studies in humans and animal models, and predisposing factors. Genetic and biochemical studies and investigations in animal models provide further insight on the pathophysiology and strategies for better treatment.

Role of hormones and blood lipids in the pathogenesis of acne vulgaris in non-obese, non-hirsute females

Context:

Acne vulgaris (AV) is a common disease affecting all ages and ethnic groups. Androgens, skin and serum lipids, inflammatory signaling and regulatory neuropeptides seem to be involved in this multi-factorial process.

Aim:

The aim of this work was to determine hormonal levels and lipid profile in non-obese, non-hirsute females with AV.

Subjects and Methods:

A total of 60 non-obese, non-hirsute female cases with different grades of AV and 60 age- and gender-matched healthy volunteers were included. Measurement of serum total and free testosterone, sex hormone binding globulin (SHBG), estradiol and progesterone and blood lipids was done during the luteal phase of the menstrual cycle.

Results:

Total testosterone, free testosterone (FT) and progesterone levels were significantly higher (P < 0.001 for all) while estradiol levels (P < 0.001) and SHBG (P < 0.01) were significantly lower in cases than controls. Total cholesterol and low density lipoprotein cholesterol (LDL-C) levels were significantly higher (P < 0.001 for both) while high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-1 (ApoA-1) levels were significantly lower (P < 0.001 for both) in cases than controls. Higher values of FT (P = 0.03) and SHBG (P = 0.02) and lower values of estradiol (P = 0.04) levels were significantly in favor of severe acne. Higher values of cholesterol (P < 0.001) and LDL-C (P = 0.03) and lower values of HDL-C (P = 0.01) and ApoA-1 (P = 0.02) levels were significantly associated with severe acne.

Conclusion:

Changes in hormone levels and lipid profile in non-obese and non-hirsute females with AV should be considered in disease pathogenesis and in treatment prescription of these patients.

Development and homeostasis of the sebaceous gland

The important role of epidermal appendages especially the sebaceous gland has only recently been recognized. In particular, it has been convincingly shown that normal development and maintenance of the sebaceous gland are required for skin homeostasis since atrophic sebaceous glands and disturbances in sebaceous lipid composition result in major defects of the physiological barrier and maintenance of the skin. Consequently, it is important to unravel the signaling network controlling proper sebaceous lineage differentiation in mammalian skin and to understand the underlying mechanisms leading to severe skin diseases, including abnormal proliferation and differentiation of the gland, defects of the lipid metabolism and barrier, as well as sebaceous tumor formation. Over the last years, results from transgenic and knock out mouse models manipulating distinct signaling pathways in the skin as well as the detailed analysis of human sebaceous gland-derived cell lines provided new insights into crucial mediators balancing proliferation and differentiation of the sebaceous gland. Here, we discuss our current knowledge of in vivo mechanisms of sebaceous gland development, maintenance and disorders and highlight recent contributions to the field of sebaceous gland biology.

The role of neuropeptides in the multifactorial pathogenesis of acne vulgaris

BACKGROUND

Central or peripheral stress may induce the development of clinical inflammation in the pilosebaceous unit (PSU) leading to the development or to exacerbation of preexisting acne. The presence of a complete corticotropin-releasing hormone (CRH) system has been confirmed in human sebocytes in vitro. CRH is capable to induce lipid synthesis, steroidogenesis and interact with testosterone and growth hormone. alpha-Melanocyte-stimulating hormone (alpha-MSH) and its receptors can regulate melanogenesis as well as affect inflammation, apoptosis and sebogenesis.

OBJECTIVES

The purpose of the study was to investigate by immunohistochemistry if changes of CRH/CRH-binding protein (CRHBP)/CRH receptors (CRHR) as well as melanocortin-1 receptor (MC-1R) expression are detectable in acne lesions vs. normal skin, especially in the sebaceous gland (SG).

RESULTS

Very strong expression of CRH was observed in acne-involved skin in SG cells comparing with weaker expression in non-involved and normal skin SG. The strongest reaction for CRHBP in acne-involved SG was in differentiating sebocytes. CRHR-1 and -2 exhibited the strongest expression in sweat glands and SG, respectively. Sebocytes and cells of the ductus seboglandularis (DSG) of acne-involved and non-involved skin showed very intense MC-1R expression in contrast to less intense scattered immunoreactivity in normal skin samples.

METHODS

33 patients with acne vulgaris and 8 age-matched volunteers without acne participated in the study. Skin biopsies were taken from acne-involved face, the non-involved thigh skin of the same patients and from normal human skin.

CONCLUSIONS

These data suggest that NP, such as the complete CRH system and MC-1R, are involved in the pathogenesis of acne.

Pharmacologic Modulation of Sebaceous Gland Activity: Mechanisms and Clinical Applications

Acne vulgaris is a common skin condition seen by physicians. It primarily affects adolescents, but can continue into adulthood. A key factor in the pathogenesis of acne is sebum production. Typical therapy includes combinations of topical retinoids and antimicrobials for mild acne, with the addition of oral antibiotics for moderate to severe disease. In the most recalcitrant cases or for nodulocystic acne, oral retinoids are indicated. In women who fail to respond to conventional treatment, hormonal therapy is often used adjunctively. Only isotretinoin and hormonal therapy improve acne via their action on the sebaceous glands. This article focuses on the mechanisms by which these treatment modalities act on the sebaceous glands and their clinical use in the practice of medicine.

Augmentation of Lipogenesis by 15-Deoxy-Δ12,14-Prostaglandin J2 in Hamster Sebaceous Glands: Identification of Cytochrome P-450-mediated 15-Deoxy-Δ12,14-Prostaglandin J2 Production

Prostaglandins (PGs) play important roles in the regulation of cutaneous cell functions under physiological and pathological conditions. In this study, we examined the involvement of PGs in sebocyte lipogenesis using non-steroidal anti-inflammatory drugs in vivo and in vitro. Hamster auricle sebocytes spontaneously differentiated to accumulate intracellular triacylglycerol (TG), under which the relative levels of 15-deoxy-Delta(12,14)-PGJ2 (15d-PGJ2) to PGF(2alpha) and PGE2 increased. 15d-PGJ2 was found to augment the formation of lipid droplets, which was because of an increase of TG synthesis by diacylglycerol acyltransferase (DGAT). Furthermore, sebocytes constitutively produced cyclooxygenase 2 (COX-2), but not COX-1, in vivo and in vitro. When sebocytes were treated with COX inhibitors such as indomethacin, diclofenac, or NS-398, the production of PGF(2alpha) and PGE2 decreased. The production of 15d-PGJ2, however, was increased in these inhibitor-treated sebocytes. In addition, indomethacin, diclofenac, and NS-398 augmented the synthesis of TG along with the increase in DGAT activity. Similarly, topical administration of indomethacin to hamster auricles caused the development of sebaceous glands with the augmentation of sebum deposition in vivo. Furthermore, indomethacin and NS-398-augmented 15d-PGJ2 production and TG synthesis were suppressed by a non-selective cytochrome P-450 (CYP) inhibitor, SKF-525A. A ligand activator of peroxisome proliferation activating receptor gamma (PPARgamma), troglitazone-induced synthesis of TG, however, was not altered even in the presence of SKF-525A. These results suggest that 15d-PGJ2 is a crucial stimulator of sebocyte lipogenesis by augmenting DGAT-mediated synthesis of TG. In addition to the COX-2-dependent pathway of PG synthesis, our findings suggest a sebocyte-specific pathway of 15d-PGJ2 production by CYP, the activity of which may be evoked by inhibiting COX-2.

Expression of perilipin A on the surface of lipid droplets increases along with the differentiation of hamster sebocytes in vivo and in vitro

To clarify the involvement of perilipin, a lipid-droplet-surface protein associated with adipocytes and steroidogenic cells, in the differentiation of sebocytes, we investigated the expression of perilipin in sebaceous glands in vivo and in vitro. Perilipin was expressed in sebaceous glands of the hamster auricle in vivo and was localized at the surface of intracellular lipid droplets in differentiated hamster sebocytes in vitro. Western blot analysis showed that perilipin with a molecular weight of approximately 57 kDa, which was identical to that in differentiated mouse 3T3-L1 adipocytes, was detected in cultured sebocytes, indicating that sebaceous glands expressed perilipin A. In addition, the production of perilipin A in cultured sebocytes was transcriptionally augmented by sebocytic-lipogenesis stimulators, insulin, and 5alpha-dihydrotestosterone, whereas it was decreased by a suppressor of sebocytic differentiation, epidermal growth factor. Furthermore, hamster sebocytes were found to express peroxisome proliferation-activating receptor alpha and gamma1, the activation of which by WY14643 and troglitazone, respectively, caused the transcriptional augmentation of perilipin A expression along with an increase in levels of triacylglycerols in lipid droplets in sebocytes. Therefore, these results provide novel evidence that the expression of perilipin A increases on the surface of intracellular lipid droplets augmented along with the differentiation of hamster sebocytes.

Effects of UV irradiation on the sebaceous gland and sebum secretion in hamsters

BACKGROUND

Although an understanding of the photobiology of the skin has been extensively advanced recently, the effect of ultraviolet (UV) radiation on sebaceous glands is not well known.

OBJECTIVE

In this study, we examined the direct effect of UV radiation on cultured sebocytes from hamsters in vitro experimental system. Moreover, we examined whether UV-induced peroxidation of skin surface lipids may affect barrier function of horney layer.

METHODS

We irradiated cultured sebocytes from hamsters, which have similar biological characteristics to the human sebocytes, with UV radiation. Moreover, transepidermal water loss (TEWL) was examined after topical application of cholesterol or triglyceride (TG) and UV exposures on the back of hamsters.

RESULTS

The number of sebocytes were increased significantly (120-140%) after 4 days as compared with the non-irradiated controls. Lipid production in sebocytes was also increased on day 7 in an irradiation-dependent manner up to 4.1 times of the pre-irradiated level. When UVB was irradiated to TG- or cholesterol-applied skin at the minimum ear-swelling dose, TEWL increased twice or more as compared with UVB irradiation to unapplied sites. When in vitro-irradiated TG, in vitro-irradiated cholesterol, TG-peroxide (TG-OOH), and cholesterol-peroxide (CHO-OOH) were applied to the skin, TEWL increased significantly.

CONCLUSION

These results suggest that UVB may directly activate the functions of the sebaceous gland in vivo to produce increased amounts of sebum, which may undergo peroxidation by UV light and damage the barrier functions of the skin.

Cutaneous androgen metabolism: basic research and clinical perspectives

The skin, especially the pilosebaceous unit composed of sebaceous glands and hair follicles, can synthesize androgens de novo from cholesterol or by locally converting circulating weaker androgens to more potent ones. As in other classical steroidogenic organs, the same six major enzyme systems are involved in cutaneous androgen metabolism, namely steroid sulfatase, 3beta-hydroxy-steroid dehydrogenase, 17beta-hydroxysteroid dehydrogenase, steroid 5alpha-reductase, 3alpha-hydroxysteroid dehydrogenase, and aromatase. Steroid sulfatase, together with P450 side chain cleavage enzyme and P450 17-hydroxylase, was found to reside in the cytoplasm of sebocytes and keratinocytes. Strong steroid sulfatase immunoreactivity was observed in the lesional skin but not in unaffected skin of acne patients. 3beta-hydroxysteroid dehydrogenase has been mainly immunolocalized to sebaceous glands, with the type 1 being the key cutaneous isoenzyme. The type 2 17beta-hydroxysteroid dehydrogenase isoenzyme predominates in sebaceous glands and exhibits greater reductive activity in glands from facial areas compared with acne nonprone areas. In hair follicles, 17beta-hydroxysteroid dehydrogenase was identified mainly in outer root sheath cells. The type 1 5alpha-reductase mainly occurs in the sebaceous glands, whereby the type II isoenzyme seems to be localized in the hair follicles. 3alpha-hydroxysteroid dehydrogenase converts dihydrotestosterone to 3alpha-androstanediol, and the use of 3alpha-androstanediol glucuronide serum level to reflect the hyperandrogenic state in hirsute women may be a reliable parameter, especially for idiopathic hirsutism. In acne patients it is still controversial if 3alpha-androstanediol glucuronide or androsterone glucuronide could serve as suitable serum markers for measuring androgenicity. Aromatase, localized to sebaceous glands and to both outer as well as inner root sheath cells of anagen terminal hair follicles, may play a "detoxifying" role by removing excess androgens. Pharmacologic development of more potent specific isoenzyme antagonists may lead to better clinical treatment or even prevention of androgen-dependent dermatoses.

Androgen deficiency, Meibomian gland dysfunction, and evaporative dry eye

OBJECTIVE

We have recently discovered that women with primary and secondary Sjögren's syndrome are androgen-deficient. We hypothesize that this hormone insufficiency contributes to the meibomian gland dysfunction, tear film instability, and evaporative dry eye that are characteristic of this autoimmune disorder. If our hypothesis is correct, we predict: (1) that androgens regulate meibomian gland function, control the quality and/or quantity of lipids produced by this tissue, and promote the formation of the tear film's lipid layer; and (2) that androgen deficiency, due to an attenuation in androgen synthesis (e.g., during Sjögren's syndrome, menopause, aging, complete androgen-insensitivity syndrome [CAIS] and anti-androgen use), will lead to meibomian gland dysfunction and evaporative dry eye. The following studies were designed to test these predictions.

METHODS

Experimental procedures included clinical studies, animal models, and histological, biochemical, molecular biological, and biomedical engineering techniques.

RESULTS

Our results demonstrate that: (1) androgens regulate the meibomian gland. This tissue contains androgen receptor mRNA, androgen receptor protein within acinar epithelial cell nuclei, and Types 1 and 2 5alpha-reductase mRNAs. Moreover, androgens appear to modulate lipid production and gene expression in mouse and/or rabbit meibomian glands; and (2) androgen deficiency may lead to meibomian gland dysfunction, altered lipid profiles in meibomian gland secretions, tear film instability, and evaporative dry eye. Thus, we have found that anti-androgen therapy in men is associated with meibomian gland disease, a decreased tear film breakup time, and functional dry eye. Furthermore, we have discovered that androgen receptor dysfunction in women with CAIS is associated with meibomian gland changes and a significant increase in the signs and symptoms of dry eye. Of interest, we have also found that androgen deficiency is associated with significant and striking alterations in the neutral and polar lipid patterns of human meibomian gland secretions.

CONCLUSIONS

Our findings show that the meibomian gland is an androgen target organ and that androgen deficiency may promote meibomian gland dysfunction and evaporative dry eye. Overall, these results support our hypothesis that androgen deficiency may be an important etiologic factor in the pathogenesis of evaporative dry eye in women with Sjögren's syndrome.

Epidermal growth factor and 1alpha,25-dihydroxyvitamin D3 suppress lipogenesis in hamster sebaceous gland cells in vitro

We have previously reported the establishment of a culture system of hamster auricular sebocytes. Although their morphologic and biochemical properties are very similar to those of human sebocytes, the regulation of lipogenesis is not clear. Therefore, we investigated the effect of epidermal growth factor, all-trans retinoic acid, 1alpha,25-dihydroxyvitamin D3, and androgens such as testosterone and 5alpha-dihydrotestosterone on lipogenesis in cultured hamster sebocytes. Intracellular lipid droplets detected with Oil-Red-O staining were observed in 5 d cultures and increased in a time-dependent manner; 40.7% +/- 1.11% of 2 wk cultured cells tested lipid-positive by flow cytometric analysis. When the hamster sebocytes were cultured in the presence of epidermal growth factor, all-trans retinoic acid, or 1alpha,25-dihydroxyvitamin D3, the intracellular lipid droplets were diminished by all-trans retinoic acid and epidermal growth factor, and slightly by 1alpha,25-dihydroxyvitamin D3. The intracellular lipid droplets consisted mainly of triglycerides (71.8%) and, as minor components, cholesterol (18.0%), wax esters (3.6%), and free fatty acids (6.6%). Epidermal growth factor and all-trans retinoic acid decreased the intracellular accumulation of triglycerides (92.6% and 96.1% inhibition, respectively) and free fatty acids (54.3% and 62.6% inhibition, respectively) in the sebocytes. In addition, 1alpha,25-dihydroxyvitamin D3 decreased the triglyceride level (34.3% inhibition), but augmented the accumulation of wax esters (30% increase). There was no difference in the level of cholesterol as a result of these treatments, however. In contrast, 5alpha-dihydrotestosterone augmented the formation of intracellular lipid droplets along with an increase in the accumulation of triglycerides in hamster sebocytes. Our findings that regulation of lipogenesis by all-trans retinoic acid and androgen in hamster sebocytes is identical to regulation in humans suggest that hamster sebocytes are useful for the elucidation of sebaceous function at the cellular level. Furthermore, this is the first evidence that epidermal growth factor and 1alpha,25-dihydroxyvitamin D3 may act as suppressors in the regulation of lipogenesis in hamster sebocytes in vitro.

Role of hormones in pilosebaceous unit development

Androgens are required for sexual hair and sebaceous gland development. However, pilosebaceous unit (PSU) growth and differentiation require the interaction of androgen with numerous other biological factors. The pattern of PSU responsiveness to androgen is determined in the embryo. Hair follicle growth involves close reciprocal epithelial-stromal interactions that recapitulate ontogeny; these interactions are necessary for optimal hair growth in culture. Peroxisome proliferator-activated receptors (PPARs) and retinoids have recently been found to specifically affect sebaceous cell growth and differentiation. Many other hormones such as GH, insulin-like growth factors, insulin, glucocorticoids, estrogen, and thyroid hormone play important roles in PSU growth and development. The biological and endocrinological basis of PSU development and the hormonal treatment of the PSU disorders hirsutism, acne vulgaris, and pattern alopecia are reviewed. Improved understanding of the multiplicity of factors involved in normal PSU growth and differentiation will be necessary to provide optimal treatment approaches for these disorders.

[Hormones, fungi and skin]

It is indicated by some epidemiological and clinical observations, that steroidal hormones may belong to those factors that are capable to influence the clinical courses of mycotic infections in man. Several fungal species, including pathogenic ones, are able to produce or metabolize steroidal hormones, or their growth can be affected by such hormones. Since, on the other hand, the steroid-responsive human skin is also capable to synthesize and convert steroidal hormones, the relationship between pathogenic fungi and host may be influenced by hormonal mediators in dermatomycoses.

Evidence of heterogeneity and quantitative differences of the type 1 5alpha-reductase expression in cultured human skin cells--evidence of its presence in melanocytes

Steroid 5alpha-reductase is of crucial importance in androgen physiology because it catalyzes the conversion of testosterone into the more potent 5alpha-dihydrotestosterone in androgen-regulated target tissues. The enzyme occurs in two isoforms, whereby type 1 isozyme exists mainly in the skin and type 2 in the prostate. By using human cell cultures, we examined cutaneous expression and subcellular localization of type 1 5alpha-reductase in vitro. In immunocytochemistry, type 1 5alpha-reductase was detected in the cytoplasm of cultured human sebocytes, keratinocytes, fibroblasts, dermal microvascular endothelial cells, hair dermal papilla cells, and melanocytes. In western blot studies, two closely lying bands of 21-27 kDa were detected, possibly indicating heterogeneity of the type 1 5alpha-reductase in all the cell types tested, with the exception of beard dermal papilla cells. Northern blot studies revealed most abundant type 1 mRNA in neonatal foreskin keratinocytes, followed by adult facial sebocytes. Occipital hair dermal papilla cells presented higher levels of type 1 5alpha-reductase mRNA than those of beard. These findings were confirmed by semiquantitative reverse transcriptase polymerase chain reaction coupled with high performance liquid chromatography analysis. Taken together, it seems likely that in cultured human skin cells there exist (i) heterogeneity of type 1 5alpha-reductase protein and (ii) quantitative differences in its transcriptional and translational expression levels.

Localization and regulation of expression of the FAR-17A gene in the hamster flank organs

A quantitative in situ hybridization study was carried out to determine the precise localization and androgen regulation of the flank organ regulated (FAR-17A) mRNA expression in the different cellular components of the hamster flank organs. Although FAR-17A mRNA was highly expressed in the epithelial cells of the sebaceous glands, it was also found in the outer root sheath of the hair follicles and in melanocytes. The changes in FAR-17A mRNA levels, in the size of the flank organ and sebaceous gland areas as well as in the weight of the seminal vesicles and prostate, were compared following castration and after 5alpha-dihydrotestosterone treatment. FAR-17A mRNA levels were already significantly decreased 1 d after castration, in parallel with a concomitant decrease in the number of labeled cells with the FAR-17A probe. A maximal decrease was found 7 d after castration. The other parameters were significantly reduced later. After 7 d of treatment with dihydrotestosterone, all values returned to those found in intact animals. Similar stimulatory effects on these parameters were observed after treatment with the adrenal sex steroid precursor dehydroepiandrosterone. These data show that all of the components of the flank organs (sebaceous glands, hair follicles, and melanocytes) express the flank organ regulated (17A) type gene (FAR-17A) gene and that its expression is stimulated by treatment with either dihydrotestosterone or dehydroepiandrosterone. Moreover, FAR-17A mRNA levels respond to androgen stimulation more rapidly than the standard morphologic parameters, revealing that the FAR-17A gene could be a more sensitive and cell specific marker to study the mechanisms of androgen action in the skin.