Expression of melanocortin receptors on cutaneous fibroblastic cells – collagen and beyond

Abstract

UV-exposition is considered as the main reason for the development of cancers of the skin. However, 90 to 100% of the Vitamin-D reqirement is formed within the skin through the action of sunlight. Considering the results of epidemiological studies, that have detected an association of Vitamin-D deficiency with various types of cancer (e.g. colon-, prostate-and breast cancer), this is a real dilema. The cancer protective effect of vitamin-D is contributed to the extra renal, local production of 1a,25(OH) 2 D 3 by the 25-hydroxyvitamin D-1a-hydroxylase, which has been detected in various tissues. In respect of the novel functions of vitamin-D and the risk of adverse consequences in case of deficiency we have screened sun deprived risk groups (A: patients with genodermatoses connected with defects in sun-induced DNA repair: n ¼ 4: 3 patients with xeroderma pigmentosum and 1 patient with basal cell nevus syndrome; and B: non vitamin-D substituted renal transplant recipients under immunosuppressants: n ¼ 33) for their vitamin-D status. As measure of the vitamin-D store and as substrate for the 25-hydroxyvitamin D-1a-hydroxylase basal 25(OH)D 3 serum levels (Nichols Institute Diagnostika GmbH, Bad Nauheim, Germany) have been analysed. In both groups decreased basal 25(OH)D 3 serum levels were detected. Therefore we demand a monitoring of vitamin-D status in patients practising sun protection, in case of vitamin-D deficiency an oral substitution should be recommended.Effect of UVB radiation emitted from the narrowband TL-01 lamp (311 nm) on the calcitriol synthesis in organotypic cultures of keratinocytesThe skin is the only tissue yet known in which the complete UVB-induced pathway from 7-dehydrocholesterol (7-DHC) to hormonally active calcitriol (1a,25-dihydroxyvitamin D 3 ) occurs under physiological conditions. It is well known that both calcitriol and UVB radiation exert potent antipsoriatic effects. We speculate that the therapeutic effect of UVB radiation can be

Crucial role of the melanocortin receptor MC1R in experimental colitis

“…15 17 20 21 Among all cloned melanocortin receptors, the MC1 receptor has the highest affinity for aMSH. 22 It has been shown to be expressed by a variety of cells-for example, macrophages and monocytes, 14 a subset of cytotoxic T cells, 8 dendritic cells, 21 neutrophils, 17 endothelial cells, 23 mast cells, 24 fibroblasts, 25 and goblet cells in the duodenum. 26 Several studies have suggested that aMSH, after binding to its receptor, exerts its anti-inflammatory and immunomodulating effects by inhibiting nuclear transcription factor-kB (NFkB) activation [27][28][29][30] and by protection against IkBa degradation.…”