ABSTRACT
The process of skin aging is a combination of an extrinsic and intrinsic aspect, and knowing the molecular changes underlying both is a prerequisite to being able to effectively counter it. However, despite its importance for a deeper understanding of skin aging as a whole, the process of intrinsic skin aging in particular has barely been investigated. In this study, the molecular changes of intrinsic skin aging were analyzed by applying 'Serial Analysis of Gene Expression' (SAGE(TM)) to skin biopsies of young and aged donors. The analysis resulted in several hundred differentially expressed genes with varying statistical significance. Of these, several genes were identified that either have never been described in skin aging before (e.g. APP) or have no identified function, e.g. EST sequences. This is the first time that intrinsic skin aging has been analyzed in such a comprehensive manner, offering a new and partially unexpected set of target genes that have to be analyzed in more detail in terms of their contribution to the skin aging process.
ABSTRACT
A tissue engineered human skin equivalent is successfully used for the testing of raw materials and cosmetic formulations. This reconstructed skin is supported by a collagen-glycosaminoglycan-chitosan biopolymer in which human keratinocytes and dermal fibroblasts were co-cultured to form a tissue that closely reproduces the in vivo architecture of normal human skin and takes into account the complex interactions between epidermis and dermis. On the other hand, dermal and epidermal responses can be assessed separately in the dermal or skin equivalent. The three-dimensional model has important advantages compared to monolayer cell cultures and epidermis models in efficacy testing: (i) the possibility of long-term cultivation with repeated application of cream formulations containing bioactives and (ii) the similarity to human skin concerning the interaction between dermis and epidermis. These similarities include the expression of keratinocyte differentiation markers such as cytokeratin 10, filaggrin and transglutaminase, as well as proteins of the basal lamina (laminin, collagen type IV) and extracellular matrix proteins such as elastin. The efficacy of selected bioactives was determined using different endpoints, for example, stimulation of collagen synthesis in the dermal and skin equivalents was shown in comparison to vitamin C as a positive control. On skin equivalents using immunofluorescence techniques we also demonstrated stimulation of the differentiation marker filaggrin, which is important for skin moisturization. The results could be used for claim substantiation, e.g. for the treatment of dry and aged skin.
ABSTRACT
In the treatment of psoriasis with topical vitamin D3 analogues, lesional and perilesional irritation is the main side-effect. The aim of this study was to investigate whether local side-effects generated by tacalcitol, a vitamin D3 analogue, show concentration dependence. 3 different concentrations of tacalcitol (0.4; 4; 40 microg/g ointment) and the vehicle were applied on normal skin of the back of 25 healthy volunteers under occlusive conditions for 5 days. Assessment of erythema, infiltration and scaling as well as measurement of transepidermal water loss (TEWL) was performed on days 1 to 5. On day 5, additional skin barrier tests (DMSO test, alkali resistance test) were performed. Erythema and slight infiltration, but no scaling, were observed in a number of subjects without significant differences. TEWL also did not show significant differences for the test formulations, though there was a tendency towards lower values in the untreated areas. In the skin barrier tests, a tendency towards higher alkali resistance in the test areas treated with 40 microg tacalcitol/g ointment was detected. Thus, under occlusive conditions, the irritant potential of tacalcitol is very low. There is no convincing evidence of concentration dependence in irritation generated by tacalcitol when applied under occlusive conditions.
Subject(s)
Dermatologic Agents/adverse effects , Dihydroxycholecalciferols/adverse effects , Erythema/chemically induced , Irritants/adverse effects , Administration, Topical , Adult , Dermatologic Agents/administration & dosage , Dihydroxycholecalciferols/administration & dosage , Dose-Response Relationship, Drug , Double-Blind Method , Evaluation Studies as Topic , Female , Humans , Male , Middle Aged , Ointments , Psoriasis/drug therapy , Severity of Illness IndexABSTRACT
Lichen ruber planus is considered a T-cell mediated immunologic reaction with unclear pathogenesis. Drugs and infections (especially hepatitis B and C) are well-known provocation factors. After an infection with scabies a 13 year old boy developed a generalized lichen planus including bullous lesions. For the first time scabies is presented as a trigger for lichen planus. In childhood, lichen planus is characterized by atypical clinical features and sometimes a severe course.
