ISSN:1660-5527    

DOI:10.1159/000210842

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:1660-5527    

DOI:10.1159/000210851

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:1660-5527    

DOI:10.1159/000210852

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:1660-5527    

DOI:10.1159/000210853

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

In this review, we describe three models of epidermis reconstructed on dermal substrates and utilized as an alternative to animal models. An almost normal epidermis is obtained when culture conditions are created that mimic the physiological conditions. The reconstruction of this epidermis allows us to evaluate the effects of substances such as retinoids and hormones on their target cell, namely the epidermal keratinocyte, and to vizualize the alteration of morphogenesis and architecture of the epidermis under the influence of such hormones. These cultures of reconstructed epidermis on firm substrates lifted to the air-liquid interface show a great potential in medical and pharmacological research since the systemic and topical actions of drugs as well as their metabolism can be studied.

ISSN:1660-5527    

DOI:10.1159/000210854

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Oral and epidermal rat keratinocytes when cultured on a matrix of type I collagen fibrils at the interface between the gaseous and liquid phases of a culture form a highly ordered stratified squamous epithelium. Autoradiographic studies of cells labeled by tritiated thymidine indicate that the keratinocytes are capable of autoregulating cell division. Early confluent cultures exhibit 51 % of basal cells labeled, a percentage that decreases to 18% when a fully differentiated stratified squamous epithelium is formed. Such a decrease in labeling occurs in cultures where the mitotically active basal cells have unimpeded access to culture medium supplied from below and when no cell type other than the keratinocyte is present in the culture. Additionally, the transit of keratinocytes from the basal cell layer through other viable cell strata to the layer of terminally differentiated cells can be followed by tracking cells labeled with tritiated thymidine. In cultures of oral keratinocytes, cells move from the basal cell layer to the cornified layer at a maximum rate of 7 days, while virtually all labeled cells (91 %) are localized in the terminally differentiated cell layer 14 days following labeling. Keratinocyte cultures grown in culture at an air-liquid interface exhibit tissue organization that closely resembles the native, parent tissue. Such cultures can be useful in studying the effects of pharmacologic mediators of cell division and cell transit.

ISSN:1660-5527    

DOI:10.1159/000210855

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Epidermis was obtained in vitro after air exposure of keratinocyte cultures grown on a dermal equivalent. Some cultures were established from enzymatically dissociated keratinocytes of either interfollicular epidermis or hair follicle outer root sheath. Others resulted from centrifugal outgrowth of epidermal sheet, out of skin biopsies or hair follicles, which were directly implanted into dermal equivalents. Whatever the system used, a multilayered epidermis was obtained with an overall architecture resembling that of human epidermis. However, depending on the tissue culture method used and the source of keratinocytes, significant differences were observed. The most striking finding was the difference in 67 kDa keratin expression: the only case where it was strictly suprabasal and homogeneously expressed in the cytoplasm of the cells, as in normal epidermis, was found in the epidermis obtained from hair follicle explants. With the other methods, the expression of this marker was delayed and patchy. These results are discussed in terms of possible intrinsic differences between interfollicular and follicular keratinocytes.

ISSN:1660-5527    

DOI:10.1159/000210856

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Reconstruction of skin requires both the dermal and epidermal equivalent of the skin. We have developed a reconstructed skin composed of two compartments: (1) a dermal equivalent comprising an acellular dermal substrate populated by foreskin fibroblasts and (2) an epidermis regenerated from normal human keratinocytes seeded onto the dermal equivalent. The dermal substrate contains type I and III collagen and glycosaminoglycans (GAGs) cross-linked by chitosan. Fibroblasts seeded into the porous structure of the dermal substrate provide a dermal equivalent suitable to support epidermal cells. Keratinocytes attach quickly, exhibit mitotic activity and form a continuous and stratified epidermis. After 2 weeks of culture, histological sections show a basal layer with cuboidal cells attached to the dermal equivalent and several suprabasal cell layers including the stratum corneum. Transmission electron microscopy revealed the cell membrane densification (hemidesmosomes) at the dermoepidermal junction; however, the lamina densa was found discontinuous at this stage. We noted the presence of lipid vesicles in spinous layer and keratohyalin granules in granular layer. The epidermal differentiation was complete terminal with the stratum corneum containing several layers of corneocytes filled with tonofilaments. Reconstructed skin, based on our chitosan-cross-linked collagen-GAG matrix is moφhologically equivalent to normal human skin and should thus provide a useful tool for in vitro toxicological studies as well as a suitable wound covering for the treatment of patients with severe burns

ISSN:1660-5527    

DOI:10.1159/000210857

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The purpose of this study was to establish the validity of the stratified, cornified keratinocyte culture as a model for investigating cutaneous toxicities. This pseudoepidermis, grown on a nylon membrane at the air-liquid interface, responded to topical application of a known vesicant similarly to the response of the tissue in vivo. Alterations in the morphology of the in vitro model also resembled pathological changes seen in in vivo models after exposure to this agent. The effects of the skin irritants benzoate and salicylate on protein and DNA synthesis in the culture were also similar to those observed in vivo.

ISSN:1660-5527    

DOI:10.1159/000210858

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

In order to evaluate the epidermal permeability barrier of in vitro reconstructed epidermis, the penetration of nitroglycerin (NG) and sucrose were measured across human keratinocytes cultured at the air-liquid interface, using de-epidermized dermis (DED) as a substrate. In the presence of reconstructed epidermis on top of DED the penetration rate of sucrose is about 100 times and that of NG 2 times lower, as compared to DED only, indicating that the stratum corneum of the cultured epidermis exhibits considerable barrier capacity. The permeability of reconstructed epidermis was for both solutes higher (3- to 10-fold) than that of freshly excised human skin. Based on the impaired barrier function and distribution of various differentiation markers it can be concluded that the reconstructed human epidermis used in the present study shows a high extent of similarity with hyperproliferating epidermis.

ISSN:1660-5527    

DOI:10.1159/000210859

出版商:S. Karger AG    

年代:1990

数据来源: Karger