693 Blocking negative effects of senescence in human skin fibroblasts with a plant extract

Abstract

the Republic of) Human skins protect their physiological and structural integrities from various insults such as UVB-irradiation (UV-IR). UV-IR induces multiple downstream signaling pathways that regulate expression of genes. Although human stem cell conditioned mediums show the regenerative effects on photo-aged skin, the molecular mechanism of epithelial precursor cellconditioned media (EPCs-CM) action on photo-aged skin is not elucidated yet. We examined whether EPCs-CM supplementation attenuates UVB-mediated skin photo-aging and regulate UVB-induced ERK signaling on dermal fibroblasts and 3-dimentional human skin equivalents (3D HSE). 3D HSE has been used with the aim of analyzing regenerative photo-protection after UV exposure. EPCs-CM treatment is carried out with various concentrations on dermal fibroblasts (DFs). Protein expressions of MMP1 and procollagen-I in skin aging are evaluated by Western blot, and Immunohistochemistry (IHC). Modulation of ERK signaling by EPCs-CM treatment are examined in DFs and 3D HSE exposed to UVB-IR Our current studies show that UVB-IR up-regulates the expression of MMP-1 and decreases the level of procollagen-1 in primary human dermal fibroblasts respectably. However, EPCs-CM treatment recovers the expression of MMP-1 and procollagen-1 regulated by UVB-IR. Furthermore, EPCs-CM delays UVB-mediated senescence status and inhibits UVB-induced ERK phosphorylation in 3D HSE. Therefore, our studies demonstrate that EPCs-CM may protect skin damages via inhibiting UVB-mediated ERK activation, suggesting that EPCs-CM can be useful material for repair and regeneration of photo-aged skin. 689Silver released from wound dressings damage skin fibroblasts and keratinocytes and ex vivo skin and 2 Cell Physiology Group, Contipro a.s., Dolni Dobrouc, Czech Republic Silver is a favourite antiseptic used in wound healing products, yet it exhibits oxidative damage to eukaryotic cells. We evaluated toxicity of silver dressings to skin cells. Three silverimpregnated bandages were investigated e silver with carboxymethyl cellulose (Ag-CMC), silver with carboxymethyl cellulose and alginate (Ag-CMC-ALG) and nanocrystalline silver on polyester (Ag 0 -PE). Silver was eluted from the bandages and the extracts were assessed in MTT viability test on primary normal human dermal fibroblasts (NHDF) and normal human epidermal keratinocytes (NHEK). Viability of NHEK was reduced by more than 30% and by more than 70% in NHDF after 24 h. After incubation with the bandage extracts, NHDF and NHEK were losing their morphology and were necrotic. Silver dressings induced TNF-a and IL-6 release after 24 h incubation with blood monocytes. Contact toxicity of the bandages on monolayer of mouse 3T3 fibroblasts showed clear halo zones indicating dead cells around the bandages. We investigated, if the silver toxic effects are relevant to intact skin of porcine auricles. The ex vivo skin was incubated in direct contact with the silver bandages for 27 and 51 h. Silver could penetrate the skin as visualised by silver-staining ...