Expression of growth-factor receptors in normal and regenerating human periodontal cells

Growth factors are biologically active mediators that bind to specific rece ptors on target cells and regulate genes involved in cell growth, wound hea ling and regeneration. The expression of these receptors is thus of fundame ntal importance for the response of the cells to the factors. The aim here was to examine, using immunohistochemistry and flow cytometry, the expressi on of growth factor receptors in normal gingiva, periodontal ligament and i n cells derived from these tissues, and also in regenerated tissues followi ng guided tissue regeneration (GTR). By immunocytochemistry platelet-derive d growth factor receptor-alpha (PDGF-R alpha) was not detected in any of th e tissues, whereas the PDGF-R beta and transforming growth factor-beta rece ptor types I and II (TGF-beta RI, RII) appeared to be upregulated in regene rated tissues compared with gingival and periodontal ligament tissues. Epid ermal growth factor receptor (EGF-R) was also notably elevated in the regen erated tissue and was strongly expressed in the gingival epithelium but not in the periodontal ligament. Neither were fibroblast growth factor recepto r-I (FGF-RI) or insulin-like growth factor receptor (IGF-R) detected in the periodontal ligament, nor in the gingiva, but they sometimes stained weakl y in the regenerated tissues. Flow cytometry (FCM) showed that all the cell s derived from the normal gingiva and the periodontal ligament expressed th e PDGF-R beta, whereas the TGF-beta RI and RII, FGF-RI and IGF-R were detec ted in only a proportion of the total cells. In contrast, none of the cells expressed the PDGF-R alpha or the EGF-R. These observations show that the growth factor receptors are differentially expressed by the periodontal tis sues and cells and suggest that the corresponding factors may also be diffe rentially involved in periodontal wound healing and regeneration. (C) 2001 Elsevier Science Ltd. All rights reserved.