Enamel matrix derivative induces matrix synthesis by cultured human periodontal fibroblast cells

Background: Periodontal wound healing and regeneration require that new mat rix be synthesized, creating an environment into which cells can migrate. O ne agent which has been described as promoting periodontal regeneration is an enamel matrix protein derivative (EMD). Since no specific growth factors have been identified in EMD preparations, it is postulated that EMD acts a s a matrix enhancement factor. This study was designed to investigate the e ffect of EMD in vitro on matrix synthesis by cultured periodontal fibroblas ts. Methods: The matrix response of the cells was evaluated by determination of the total proteoglycan synthesis, glycosaminoglycan profile, and hyalurona n synthesis by the uptake of radiolabeled precursors. The response of the i ndividual proteoglycans, versican, decorin, and biglycan were examined at t he mRNA level by Northern blot analysis. Hyaluronan synthesis was probed by identifying the isotypes of hyaluronan synthase (HAS) expressed in periodo ntal fibroblasts as HAS-2 and HAS-3 and the effect of EMD on the levels of mRNA for each enzyme was monitored by reverse transcription polymerase chai n reaction (RTPCR). Comparisons were made between gingival fibroblast (GF) cells and periodontal ligament (PDLF) cells. Results: EMD was found to significantly affect the synthesis of the mRNAs f or the matrix proteoglycans versican, biglycan, and decorin, producing a re sponse similar to, but potentially greater than, mitogenic cytokines. EMD a lso stimulated hyaluronan synthesis in both GF and PDLF cells. Although mRN A for HAS-2 was elevated in GF after exposure to EMD, the PDLF did not show a similar response. Therefore, the point at which the stimulation of hyalu ronan becomes effective may not be at the level of stimulation of the mRNA for hyaluronan synthase, but, rather, at a later point in the pathway of re gulation of hyaluronan synthesis. In all cases, GF cells appeared to be mor e responsive to EMD than PDLF cells in vitro. Conclusions: EMD has the potential to significantly modulate matrix synthes is in a manner consistent with early regenerative events.