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.

Fibrotic enzymes modulate wound-induced skin tumorigenesis.

Fibroblasts are a major component of the microenvironment of most solid tumours. Recent research elucidated a large heterogeneity and plasticity of activated fibroblasts, indicating that their role in cancer initiation, growth and metastasis is complex and context-dependent. Here, we performed genome-wide expression analysis comparing fibroblasts in normal, inflammatory and tumour-associated skin.

Skin microbiome modulation induced by probiotic solutions.

Background: The skin is colonized by a large number of microorganisms, most of which are beneficial or harmless. However, disease states of skin have specific microbiome compositions that are different from those of healthy skin. Gut microbiome modulation through fecal transplant has been proven as a valid therapeutic strategy in diseases such as Clostridium difficile infections.

Expression of Potential Dermal Progenitor Cell Markers in the Tumour and Stroma of Skin Adnexal Malignant and Benign Tumours.

Stem cells are multipotent cells that maintain the skin epidermis including skin appendages such as hair follicle, sebaceous glands, and sweat glands. There is evidence that reciprocal signalling between the epidermis and the dermis plays an important role in skin development, homeostasis, wound repair, and skin cancer. The origin of skin cancer that derive from skin appendages is still controversial, including basal cell carcinoma and even more of rare tumours such as sebaceous carcinomas and whether those tumours originate from resident tissue stem cells.

Skin microdialysis: methods, applications and future opportunities-an EAACI position paper.

Skin microdialysis (SMD) is a versatile sampling technique that can be used to recover soluble endogenous and exogenous molecules from the extracellular compartment of human skin. Due to its minimally invasive character, SMD can be applied in both clinical and preclinical settings. Despite being available since the 1990s, the technique has still not reached its full potential use as a tool to explore pathophysiological mechanisms of allergic and inflammatory reactions in the skin.

Cytokine and Chemokine Recovery Is Increased by Colloid Perfusates during Dermal Microdialysis.

Unlabelled: Cytokines and chemokines play important roles in cell signalling, and microdialysis is a promising tool for monitoring these inflammation markers ex vivo. Therefore, the collecting of these mediators at the highest concentrations possible is crucial. Depending on the size of the mediator of interest, the collection of these high molecular mass molecules has thus far been difficult due to their low recovery, even when using high cut-off (100 kDa) microdialysis membranes.

Eczema in Psoriatico: An Important Differential Diagnosis Between Chronic Allergic Contact Dermatitis and Psoriasis in Palmoplantar Localization.

Differential diagnosis of palmoplantar non-pustular psoriasis and chronic allergic contact dermatitis (ACD) and the combination of these conditions, termed "eczema in psoriatico" (EIP), is difficult, especially in cases of isolated involvement. A blind re-evaluation of 63 archived formalin-fixed palmoplantar samples, previously diagnosed clinically as either psoriasis or chronic ACD, was performed. Samples were allocated to histopathological diagnoses of psoriasis, contact dermatitis or EIP.

A genome-wide screen identifies YAP/WBP2 interplay conferring growth advantage on human epidermal stem cells.

Individual human epidermal cells differ in their self-renewal ability. To uncover the molecular basis for this heterogeneity, we performed genome-wide pooled RNA interference screens and identified genes conferring a clonal growth advantage on normal and neoplastic (cutaneous squamous cell carcinoma, cSCC) human epidermal cells. The Hippo effector YAP was amongst the top positive growth regulators in both screens.

Treatment options for pyoderma gangrenosum.

Pyoderma gangrenosum (PG) is an orphan disease. While research on such disorders is based on only few randomized multicenter as well as retrospective studies, most of the data comes from case series of small patient groups. Apart from topical and intralesional therapeutic options for early stages and mild disease courses, treatment predominantly involves systemic therapeutic agents.

Therapieoptionen beim Pyoderma gangraenosum.

Das Pyoderma gangraenosum (PG) gehört zu den orphan diseases, deren Erforschung sich lediglich auf einzelne, randomisierte, multizentrische sowie retrospektive Studien stützen kann und überwiegend auf Fallserien an kleinen Patientenkollektiven beruht. Die Therapie basiert neben topischen und lokal intraläsionalen Therapieoptionen, bei initialem und leichtem Krankheitsverlauf, insbesondere auf der Gabe von Systemtherapeutika. Diese beinhaltet neben den systemischen Glukokortikosteroiden und Ciclosporin A (CsA) auch Biologika wie intravenöses Immunglobulin G (IVIG), die TNFα-Inhibitoren Infliximab, Adalimumab und Etanercept, den IL-12/23-Antikörper Ustekinumab, den Interleukin-1-Rezeptorantagonist Anakinra und den Interleukin-1β-Antikörper Canakinumab.

Kinetic Profile of Inflammation Markers in Human Skin In vivo Following Exposure to Ultraviolet B Indicates Synchronic Release of Cytokines and Prostanoids.

Ultraviolet B (UVB) irradiation affects epidermal cells, which respond via a cascade of inflammation markers. After initial in vitro and ex vivo experiments, this study used cutaneous microdialysis to generate a kinetic profile for 16 cytokines and 4 prostanoids in human skin in vivo. Skin areas 9 cm2 were irradiated with UVB (2× minimal erythematous dose) 16 h after catheter placement in the dermis of the volar forearms of healthy volunteers.

Effects of Topical Tacrolimus and Polyunsaturated Fatty Acids on In Vivo Release of Eicosanoids in Atopic Dermatitis During Dermal Microdialysis.

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease with release of distinct inflammatory signals. This study investigated the presence of eicosanoids in AD skin and the effect of topical agents with potential to suppress inflammation. Twelve patients with moderate AD received topical treatment on either arm with tacrolimus 0.

BLIMP1 is required for postnatal epidermal homeostasis but does not define a sebaceous gland progenitor under steady-state conditions.

B-lymphocyte-induced nuclear maturation protein 1 (BLIMP1) was previously reported to define a sebaceous gland (SG) progenitor population in the epidermis. However, the recent identification of multiple stem cell populations in the hair follicle junctional zone has led us to re-evaluate its function. We show, in agreement with previous studies, that BLIMP1 is expressed by postmitotic, terminally differentiated epidermal cells within the SG, interfollicular epidermis, and hair follicle.

Rewiring of an epithelial differentiation factor, miR-203, to inhibit human squamous cell carcinoma metastasis.

Metastatic colonization of distant organs underpins the majority of human-cancer-related deaths, including deaths from head and neck squamous cell carcinoma (HNSCC). We report that miR-203, a miRNA that triggers differentiation in multilayered epithelia, inhibits multiple postextravasation events during HNSCC lung metastasis. Inducible reactivation of miR-203 in already established lung metastases reduces the overall metastatic burden.

Epidermal barrier defects link atopic dermatitis with altered skin cancer susceptibility.

Atopic dermatitis can result from loss of structural proteins in the outermost epidermal layers, leading to a defective epidermal barrier. To test whether this influences tumour formation, we chemically induced tumours in EPI-/- mice, which lack three barrier proteins-Envoplakin, Periplakin, and Involucrin. EPI-/- mice were highly resistant to developing benign tumours when treated with 7,12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA).

High incidence of naevi-associated BRAF wild-type melanoma and dysplastic naevi under treatment with the class I BRAF inhibitor vemurafenib.

There is growing evidence that not only malign keratinocytic but also melanocytic tumours can arise during treatment with vemurafenib. During an on-going early access trial, 13 patients harbouring a BRAF-V600E mutation received vemurafenib (Zelboraf®) 960 mg twice daily to test the safety, tolerability, efficacy and response rate for advanced melanoma. Clinically or dermatoscopically suspicious cutaneous tumours under treatment with vemurafenib were excised.

c-MYC-induced sebaceous gland differentiation is controlled by an androgen receptor/p53 axis.

Although the sebaceous gland (SG) plays an important role in skin function, the mechanisms regulating SG differentiation and carcinoma formation are poorly understood. We previously reported that c-MYC overexpression stimulates SG differentiation. We now demonstrate roles for the androgen receptor (AR) and p53.

Imiquimod 3.75% cream (Zyclara) for the treatment of actinic keratoses.

Introduction: actinic keratosis is a premalignant disease with a high incidence and is a strong predictor for the development of squamous cell carcinoma. Various treatment options have been established over recent years, including topical treatment with imiquimod, 5-fluorouracil, diclofenac or photodynamic therapy, cryotherapy and surgical procedures.

Areas Covered: this review covers basic and clinical experiences with imiquimod 3.