Enamel matrix-derived protein stimulates attachment of periodontal ligament fibroblasts and enhances alkaline phosphatase activity and transforming growth factor beta(1) release of periodontal ligament and gingival fibroblasts

Background: Although it is claimed that enamel matrix-derived proteins (EMP ) can be used to promote new attachment formation around periodontally invo lved teeth, the underlying biological mechanism is not understood. It was t he aim of the present study to investigate the effects of EMP on the behavi or of human periodontal ligament (HPLF) and gingival fibroblasts (HGF) in v itro, with special focus on their attachment properties, the expression of alkaline phosphatase (ALP) activity, the release of transforming growth fac tor (TGF)beta(1), and their proliferative rate. Methods: Fibroblast populations were obtained from 10 individuals with a he althy periodontium and cultured in chemically defined medium on culture pla tes coated with EMP, purified collagen type I, or their respective vehicles . Experiments were performed in the absence of serum for periods up to 48 h ours. Results: It was shown that HGF barely attached and spread on EMP-coated sub strata, whereas HPLF attached and spread within 24 hours. However, when cul tured on purified collagen type I, both cell types showed rapid attachment and spreading. Furthermore, the expression of ALP activity was significantl y enhanced under the influence of EMP, especially in HPLF. HPLF and HGF bot h released significantly higher levels of TGF beta(1) in the presence of EM P. EMP did not influence H-3-thymidine incorporation by HPLF and HGF. Conclusions: Our results indicate that HPLF and HGF respond differently to EMP. A more rapid attachment of HPLF to this substratum might contribute, d uring the initial stages of periodontal healing, to selective outgrowth and colonization of exposed root surfaces in vivo.