New pharmaceutical concepts for sebaceous gland diseases: implementing today's pre-clinical data into tomorrow's daily clinical practice

β-1,4-Galactan suppresses lipid synthesis in sebaceous gland cells via TLR4

Sebum is a lipid mixture secreted from sebaceous glands of the skin. The excessive secretion of sebum causes acne vulgaris and seborrheic dermatitis, while its deficiency causes xerosis. Therefore, the appropriate control of sebum secretion is crucially important to keep the skin healthy. In the present study, we evaluated the effects of naturally occurring polysaccharides on lipid biosynthesis in hamster sebaceous gland cells. Among the tested polysaccharides, β-1,4-galactan, the main chain of type I arabinogalactan, most potently suppressed lipid synthesis in the sebaceous gland cells as analysed by oil red O staining. Toll-like receptor (TLR)4 inhibitors counteracted this suppressive effect and lipopolysaccharide, a TLR4 ligand, mimicked this effect, suggesting the involvement of the TLR4 signalling pathway. In the cells β-1,4-galactan significantly decreased mRNA levels of lipogenesis-related transcription factors (peroxisomeGraphical Abstract$\includegraphics{\bwartpath }$ proliferator-activated receptor γ and sterol regulatory element-binding protein 1) and enzymes (acetyl-CoA carboxylase and fatty acid synthase) as well as the glucose transporter GLUT4. Furthermore, β-1,4-galactan increased the production of lactic acid serving as a natural moisturizing factor and enhanced the proliferation of sebaceous gland cells. These results suggest potential of β-1,4-galactan as a material with therapeutic and cosmetic values for the skin.

Sebaceous immunobiology - skin homeostasis, pathophysiology, coordination of innate immunity and inflammatory response and disease associations

This review presents several aspects of the innovative concept of sebaceous immunobiology, which summarizes the numerous activities of the sebaceous gland including its classical physiological and pathophysiological tasks, namely sebum production and the development of seborrhea and acne. Sebaceous lipids, which represent 90% of the skin surface lipids in adolescents and adults, are markedly involved in the skin barrier function and perifollicular and dermal innate immune processes, leading to inflammatory skin diseases. Innovative experimental techniques using stem cell and sebocyte models have clarified the roles of distinct stem cells in sebaceous gland physiology and sebocyte function control mechanisms. The sebaceous gland represents an integral part of the pilosebaceous unit and its status is connected to hair follicle morphogenesis. Interestingly, professional inflammatory cells contribute to sebocyte differentiation and homeostasis, whereas the regulation of sebaceous gland function by immune cells is antigen-independent. Inflammation is involved in the very earliest differentiation changes of the pilosebaceous unit in acne. Sebocytes behave as potent immune regulators, integrating into the innate immune responses of the skin. Expressing inflammatory mediators, sebocytes also contribute to the polarization of cutaneous T cells towards the Th17 phenotype. In addition, the immune response of the perifollicular infiltrate depends on factors produced by the sebaceous glands, mostly sebaceous lipids. Human sebocytes in vitro express functional pattern recognition receptors, which are likely to interact with bacteria in acne pathogenesis. Sex steroids, peroxisome proliferator-activated receptor ligands, neuropeptides, endocannabinoids and a selective apoptotic process contribute to a complex regulation of sebocyte-induced immunological reaction in numerous acquired and congenital skin diseases, including hair diseases and atopic dermatitis.

Androgens and androgen receptor action in skin and hair follicles

Beyond sexual functions, androgens exert their action in skin physiology and pathophysiology. Skin cells are able to synthesize most active androgens from gonadal or adrenal precursors and the enzymes involved in skin steroidogenesis are implicated both in normal or pathological processes. Even when the role of androgens and androgen receptor (AR) in skin pathologies has been studied for decades, their molecular mechanisms in skin disorders remain largely unknown. Here, we analyze recent studies of androgens and AR roles in several skin-related disorders, focusing in the current understanding of their molecular mechanisms in androgenetic alopecia (AGA). We review the molecular pathophysiology of type 2 5α-reductase, AR coactivators, the paracrine factors deregulated in dermal papillae (such as TGF-β, IGF 1, WNTs and DKK-1) and the crosstalk between AR and Wnt signaling in order to shed some light on new promising treatments.

Endocannabinoid Tone Regulates Human Sebocyte Biology

We have previously shown that endocannabinoids (eCBs) (e.g., anandamide) are involved in the maintenance of homeostatic sebaceous lipid production in human sebaceous glands and that eCB treatment dramatically increases sebaceous lipid production. Here, we aimed to investigate the expression of the major eCB synthesizing and degrading enzymes and to study the effects of eCB uptake inhibitors on human SZ95 sebocytes, thus exploring the role of the putative eCB membrane transporter, which has been hypothesized to facilitate the cellular uptake and subsequent degradation of eCBs. We found that the major eCB synthesizing (N-acyl phosphatidylethanolamine-specific phospholipase D, and diacylglycerol lipase-α and -β) and degrading (fatty acid amide hydrolase, monoacylglycerol lipase) enzymes are expressed in SZ95 sebocytes and also in sebaceous glands (except for diacylglycerol lipase-α, the staining of which was dubious in histological preparations). eCB uptake-inhibition with VDM11 induced a moderate increase in sebaceous lipid production and also elevated the levels of various eCBs and related acylethanolamides. Finally, we found that VDM11 was able to interfere with the proinflammatory action of the TLR4 activator lipopolysaccharide. Collectively, our data suggest that inhibition of eCB uptake exerts anti-inflammatory actions and elevates both sebaceous lipid production and eCB levels; thus, these inhibitors might be beneficial in cutaneous inflammatory conditions accompanied by dry skin.

Quality of life measurement in acne. Position Paper of the European Academy of Dermatology and Venereology Task Forces on Quality of Life and Patient Oriented Outcomes and Acne, Rosacea and Hidradenitis Suppurativa

Acne causes profound negative psychological and social effects on the quality of life (QoL) of patients. The European Dermatology Forum S3-Guideline for the Treatment of Acne recommended adopting a QoL measure as an integral part of acne management. Because of constantly growing interest in health-related QoL assessment in acne and because of the high impact of acne on patients' lives, the European Academy of Dermatology and Venereology Task Force on QoL and Patient Oriented Outcomes and the Task Force on Acne, Rosacea and Hidradenitis Suppurativa have documented the QoL instruments that have been used in acne patients, with information on validation, purposes of their usage, description of common limitations and mistakes in their usage and overall recommendations.

Anti-acne drugs in phase 1 and 2 clinical trials

INTRODUCTION

Despite the impressive increase of knowledge on acne etiology accumulated during the last 20 years, few efforts have been overtaken to introduce new therapeutic regiments targeting the ideal treatment of acne. The increasing emergence of microbial resistance associated with antibiotics, teratogenicity, particularly associated with systemic isotretinoin, and the need for an adverse drug profile, which can be tolerated by the patient, make the need of new pathogenesis relevant anti-acne agents an emerging issue. Areas covered: A search for phase 1 and 2 acne treatment trials in the US National Institutes of Health database of clinical trials and the European Medicines Agency database with the key words 'acne' and 'treatment' was carried out, on 6 January 2017. Expert opinion: The detected trials mostly investigate topical agents that may act via sebosuppressive effects, antimicrobial properties or anti-inflammatory actions. The compounds under investigation include olumacostat glasaretil, cortexolone 17α-propionate, stearoyl-CoA desaturase 1 inhibitors, agents affecting the melanocortin system, omiganan, and minocycline. Systemic studied anti-acne drugs include finasteride, biologics, low dose anti-inflammatory antibiotics, and leukotriene B4 inhibitors.

Skin steroidogenesis in health and disease

The skin is an important extra-gonadal steroidogenic organ, capable of metabolizing various hormones from their precursors, as well as of synthesizing de novo a broad palette of sex steroids and glucocorticoids from cholesterol. In this manuscript, we review the major steroidogenic properties of human skin and we suggest steroidogenesis' impairment as a cardinal factor for various pathological conditions such as acne, rosacea, atopic dermatitis, and androgenic alopecia.

Differential effectiveness of selected non-psychotropic phytocannabinoids on human sebocyte functions implicates their introduction in dry/seborrhoeic skin and acne treatment

Acne is a common skin disease characterized by elevated sebum production and inflammation of the sebaceous glands. We have previously shown that a non-psychotropic phytocannabinoid ((-)-cannabidiol [CBD]) exerted complex anti-acne effects by normalizing 'pro-acne agents'-induced excessive sebaceous lipid production, reducing proliferation and alleviating inflammation in human SZ95 sebocytes. Therefore, in this study we aimed to explore the putative anti-acne effects of further non-psychotropic phytocannabinoids ((-)-cannabichromene [CBC], (-)-cannabidivarin [CBDV], (-)-cannabigerol [CBG], (-)-cannabigerovarin [CBGV] and (-)-Δ(9) -tetrahydrocannabivarin [THCV]). Viability and proliferation of human SZ95 sebocytes were investigated by MTT and CyQUANT assays; cell death and lipid synthesis were monitored by DilC1 (5)-SYTOX Green labelling and Nile Red staining, respectively. Inflammatory responses were investigated by monitoring expressions of selected cytokines upon lipopolysaccharide treatment (RT-qPCR, ELISA). Up to 10 μm, the phytocannabinoids only negligibly altered the viability of the sebocytes, whereas high doses (≥50 μm) induced apoptosis. Interestingly, basal sebaceous lipid synthesis was differentially modulated by the substances: CBC and THCV suppressed it, and CBDV had only minor effects, whereas CBG and CBGV increased it. Importantly, CBC, CBDV and THCV significantly reduced arachidonic acid (AA)-induced 'acne-like' lipogenesis. Moreover, THCV suppressed proliferation, and all phytocannabinoids exerted remarkable anti-inflammatory actions. Our data suggest that CBG and CBGV may have potential in the treatment of dry-skin syndrome, whereas CBC, CBDV and especially THCV show promise to become highly efficient, novel anti-acne agents. Moreover, based on their remarkable anti-inflammatory actions, phytocannabinoids could be efficient, yet safe novel tools in the management of cutaneous inflammations.

Systemic treatment of seborrheic dermatitis with retinol palmitate

The goal of the study. Evaluating of the effectiveness of treatment of men with a diagnosis «Seborrheic dermatitis of the scalp» by the system using of retinol palmitate. Material and methods. 36 patients every day for 2 months received overnight per os 200000 ME of retinol palmitate, and in the comparison group (39 people) antiseborrheic shampoos have been used. The dynamics of severity of skin oiliness, pruritis, erythema, peeling, infiltration, excoriations has been evaluated in points. Before and after the treatment a histological and morphometric study of biopsy material from the affected areas has been carried.The terms of relapses have been set. Results. Retinol palmitate treatment efficiency - 91.7%, antiseborrheic shampoos - 84.6%. Along with the regression of symptoms of the disease in both groups after retinol palmitate treatment significantly declined oiliness of skin; the sizes of sebaceous glands acini and the presence of differentiated sebocytes, the squares of lymphocytic-macrophage clusters in the dermis, the number of keratinocytes with vacuolated cytoplasm have been reduced. Relapses of the disease during a year occured more rare - in 21 patients out of 32 (in the comparison group- in 25 out of 31) and at a later date (in the first 3 months in 2 patients out of 32, in comparison group in 10 out of 31). Identified effects were due to the action of retinol palmitate on the morphogenesis of the sebaceous glands.

Profiling the triacylglyceride contents in bat integumentary lipids by preparative thin layer chromatography and MALDI-TOF mass spectrometry

The mammalian integument includes sebaceous glands that secrete an oily material onto the skin surface. Sebum production is part of the innate immune system that is protective against pathogenic microbes. Abnormal sebum production and chemical composition are also a clinical symptom of specific skin diseases. Sebum contains a complex mixture of lipids, including triacylglycerides, which is species-specific. The broad chemical properties exhibited by diverse lipid classes hinder the specific determination of sebum composition. Analytical techniques for lipids typically require chemical derivatizations that are labor-intensive and increase sample preparation costs. This paper describes how to extract lipids from mammalian integument, separate broad lipid classes by thin-layer chromatography, and profile the triacylglyceride contents using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This robust method enables a direct determination of the triacylglyceride profiles among species and individuals, and it can be readily applied to any taxonomic group of mammals.

Steroidogenesis in the skin: implications for local immune functions

The skin has developed a hierarchy of systems that encompasses the skin immune and local steroidogenic activities in order to protect the body against the external environment and biological factors and to maintain local homeostasis. Most recently it has been established that skin cells contain the entire biochemical apparatus necessary for production of glucocorticoids, androgens and estrogens either from precursors of systemic origin or, alternatively, through the conversion of cholesterol to pregnenolone and its subsequent transformation to biologically active steroids. Examples of these products are corticosterone, cortisol, testosterone, dihydrotesterone and estradiol. Their local production can be regulated by locally produced corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) or cytokines. Furthermore the production of glucocorticoids is affected by ultraviolet B radiation. The level of production and nature of the final steroid products are dependent on the cell type or cutaneous compartment, e.g., epidermis, dermis, adnexal structures or adipose tissue. Locally produced glucocorticoids, androgens and estrogens affect functions of the epidermis and adnexal structures as well as local immune activity. Malfunction of these steroidogenic activities can lead to inflammatory disorders or autoimmune diseases. The cutaneous steroidogenic system can also have systemic effects, which are emphasized by significant skin contribution to circulating androgens and/or estrogens. Furthermore, local activity of CYP11A1 can produce novel 7Δ-steroids and secosteroids that are biologically active. Therefore, modulation of local steroidogenic activity may serve as a new therapeutic approach for treatment of inflammatory disorders, autoimmune processes or other skin disorders. In conclusion, the skin can be defined as an independent steroidogenic organ, whose activity can affect its functions and the development of local or systemic inflammatory or autoimmune diseases. This article is part of a Special Issue entitled 'CSR 2013'.