Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We designed a new tissue-engineered skin equivalent in which complete pilosebaceous units were integrated. This model was produced exclusively from human fibroblasts and keratinocytes and did not contain any synthetic material. Fibroblasts were cultured for 35 d with ascorbic acid and formed a thick fibrous sheet in the culture dish. The dermal equivalent was composed of stacked fibroblast sheets and exhibited some ultrastructural organization found in normal connective tissues. Keratinocytes seeded on this tissue formed a stratified and cornified epidermis and expressed typical markers of differentiation (keratin 10, filaggrin, and transglutaminase). After 4 wk of culture, a continuous and ultrastructurally organized basement membrane was observed and associated with the expression of laminin and collagen IV and VII. Complete pilosebaceous units were obtained by thermolysin digestion and inserted in this skin equivalent in order to assess the role of the transfollicular route in percutaneous absorption. The presence of hair follicles abolished the lag-time observed during hydrocortisone diffusion and increased significantly its rate of penetration in comparison to the control (skin equivalent with sham hair insertion). Therefore, this new hairy human skin equivalent model allowed an experimental design in which the only variable was the presence of pilosebaceous units and provided new data confirming the importance of hair follicles in percutaneous absorption.
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PMID:Characterization of a new tissue-engineered human skin equivalent with hair. 1047 18

The treatment of severely burned patients has benefited from the grafting of skin substitutes obtained by expansion of epithelial cells in culture. The aim of this study was to evaluate whether the anatomic site chosen for harvesting skin had an impact on the quality of the derived cell cultures. Considering that hair follicles contain epithelial stem cells, we compared hairy skin sites featuring different densities and sizes of hair follicles for their capacity to generate high quality keratinocyte cultures. Three anatomic sites from adult subjects were compared: scalp, chest skin and p-auricular (comprising pre-auricular and post-auricular) skin. Keratin (K) 19 was used as a marker to evaluate the proportion of stem cells. Keratinocytes were isolated using the two-step thermolysin and trypsin cell extraction method, and cultured in vitro. The proportion of K19-positive cells harvested from p-auricular skin was about twice that of the scalp. This K19-positive cell content also remained higher during the first subcultures. In contrast to these in vitro results, the number of K19-positive cells estimated in situ on skin sections was about double in scalp as in p-auricular skin. Chest skin had the lowest number of K19-positive cells. These results indicate that in addition to the choice of an adult anatomic site featuring a high number of stem cells in situ, the quality of the cultures greatly depends on the ability to extract stem cells from the skin biopsy.
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PMID:Considerations in the choice of a skin donor site for harvesting keratinocytes containing a high proportion of stem cells for culture in vitro. 2112 25