Use this URL to cite or link to this record in EThOS:
Title: The influence of connective tissue on the epithelial phenotype of adult human keratinocytes in vitro
Author: Selvaratnam, Lakshmi
Awarding Body: Queen Mary, University of London
Current Institution: Queen Mary, University of London
Date of Award: 1995
Availability of Full Text:
Access from EThOS:
The aim of this study was to investigate the influence of supporting connective tissue in maintaining adult epithelial phenotype in vitro. Human keratinocytes, isolated from buccal and hard palate mucosa and trunk skin were cultured, both in the absence and presence of stromal tissue. Epithelial differentiation was assessed using the following parameters; histology, ultrastructural morphology, immunocytochemical detection of keratin polypeptides and other markers of differentiation, biochemical characterisation of the lipid composition of these cultures as well as their functional permeability properties to tritiated water. Systematic comparison was made throughout with intact epithelial tissues. Adult kératinocytes (particularly from non-comified buccal mucosa) retained many intrinsic phenotypic characteristics which were expressed to only a limited extent in the absence of stromal influences. Although all such cultures demonstrated an increased distribution of simple epithelial keratins, only epidermal keratinocytes also expressed the cornification-associated keratin 10. Epithelial differentiation was enhanced when kératinocytes were grown on dead de-epidermised dermis, a non-viable connective tissue substrate. Although here, epidermal kératinocytes expressed both keratin 10 and filaggrin, palatal kératinocytes remained largely non-comified. The lipid content of oral kératinocyte cultures and their permeability features closely resembled in vivo tissues while epidermal kératinocytes, containing reduced barrier-associated lipids, remained highly permeable regardless of connective tissue presence. The effects of basement membrane components and viable mesenchymal cells on adult kératinocyte differentiation were investigated by ultrastructural morphology and immunodetection of markers of maturation including keratins. Expression of characteristic keratins was independent of basement membrane although epithelial attachment and organised stratification were substantially improved in its presence. Furthermore, co culturing with dermal fibroblasts induced buccal kératinocytes to atypically express keratin 10 and filaggrin. In conclusion, adult human kératinocytes possess an intrinsic capacity to differentiate according to site-specific phenotype, but, full expression of such intrinsic differences is largely dependent on the appropriate environment, probably signalling from specific fibroblast populations. These results also indicate that the establishment of a non-comified epithelial phenotype in the adult may be less dependent on viable stromal cells than comified epithelia.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available