In situ analysis of transforming growth factor-βs (TGF-β1, TGF-β2, TGF-β3and TGF-3 type II receptor expression in malignant melanoma

We have analysed, by in situ hybridization, mRNA expression of TGF-β1, TGF-β2, TGF-β3, and of TGF-β type II receptor in benign melanocytic naevi, primary melanomas, and in skin metastases of malignant melanomas. Our results show that melanoma progression correlates with overexpression of TGF-β. All skin metastases and most primary melanomas invasive to Clark's level IV-V revealed specific TGF-β2 mRNA and protein expression. However, expression of this cytokine was not observed in benign melanocytic lesions and was detected only in one of five early primary melanomas investigated. Some primary melanomas and skin metastases also revealed specific TGF-β1 mRNA signals although expression of this isoform was not found in benign naevi. TGF-β3 expression, which was only barely detectable in benign melanocytic lesions, was enhanced in some skin metastases. Interestingly, the epidermis overlaying melanomas revealed lower levels of TGF-β3 mRNA expression than epidermis of healthy skin or epidermis adjacent to benign naevi, thereby suggesting that paracrine mechanisms between tumour cells and keratinocytes may influence melanoma development. In primary melanomas TGF-β type II receptor mRNA signals were much more heterogeneously distributed when compared to benign melanocytic naevi, suggesting variable degrees of TGF-β resistance among melanoma cells within individual lesions. However, melanoma progression appeared not to be correlated with a complete loss of TGF-β type II receptor gene expression, since all skin metastases revealed clearly detectable although heterogeneous levels of TGF-β type II receptor mRNA expressio

Topical bioavailability of triamcinolone acetonide: effect of dose and application frequency

The application frequency of topical corticosteroids is a recurrently debated topic. Multiple-daily applications are common, although a superior efficacy compared to once-daily application is not unequivocally proven. Only few pharmacokinetic studies investigating application frequency exist. The aim of the study was to investigate the effect of dose (Experiment 1) and application frequency (Experiment 2) on the penetration of triamcinolone acetonide (TACA) into human stratum corneum (SC) in vivo. The experiments were conducted on the forearms of 15 healthy volunteers. In Experiment 1, single TACA doses (300μg/cm2 and 100μg/cm2) dissolved in acetone were applied on three sites per arm. In experiment 2, single (1×300μg/cm2) and multiple (3×100μg/cm2) TACA doses were similarly applied. SC samples were harvested by tape stripping after 0.5, 4 and 24h (Experiment 1) and after 4, 8 and 24h (Experiment 2). Corneocytes and TACA were quantified by UV/VIS spectroscopy and HPLC, respectively. TACA amounts penetrated into SC were statistically evaluated by a paired-sample t-test. In Experiment 1, TACA amounts within SC after application of 1×300μg/cm2 compared to 1×100μg/cm2 were only significantly different directly after application and similar at 4 and 24h. In Experiment 2, multiple applications of 3×100μg/cm2 yielded higher TACA amounts compared to a single application of 1×300μg/cm2 at 4 and 8h. At 24h, no difference was observed. In conclusion, using this simple vehicle, considerable TACA amounts were retained within SC independently of dose and application frequency. A low TACA dose applied once should be preferred to a high dose, which may promote higher systemic exposur

Deletion of mu- and kappa-opioid receptors in mice changes epidermal hypertrophy, density of peripheral nerve endings, and itch behavior.

The mu- (MOR) and kappa- (KOR) opioid receptors have been implicated in the regulation of homeostasis of non-neuronal cells, such as keratinocytes, and sensations like pain and chronic pruritus. Therefore, we have studied the phenotype of skin after deletion of MOR and KOR. In addition, we applied a dry skin model in these knockout mice and compared the different mice before and after induction of the dermatitis in terms of epidermal thickness, epidermal peripheral nerve ending distribution, dermal inflammatory infiltrate (mast cells, CD4 positive lymphocytes), and scratching behavior. MOR knockout mice reveal as phenotype a significantly thinner epidermis and a higher density of epidermal fiber staining by protein gene product 9.5 than the wild-type counterparts. Epidermal hypertrophy, induced by the dry skin dermatitis, was significantly less developed in MOR knockout than in wild-type mice. Neither mast cells nor CD4 T(h)-lymphocytes are involved in the changes of epidermal nerve endings and epidermal homeostasis. Finally, behavior experiments revealed that MOR and KOR knockout mice scratch less after induction of dry skin dermatitis than wild-type mice. These results indicate that MOR and KOR are important in skin homeostasis, epidermal nerve fiber regulation, and pathophysiology of itching