Emdogain^® vs. Recombinant Amelogenin: Effects on Immortalized Human Periodontal Ligament Cells

Emdogain®, or enamel matrix derivative (EMD), has been reported to promote periodontal regeneration. Despite wide reports in animal and human clinical trials that renewal of the dental attachment apparatus (cementum, periodontal ligament and bone) is enhanced by the use of EMD, very little is understood of its mechanism of action. Since amelogenin (Amel) is not the sole constituent in EMD, a demonstration that it is or is not an active ingredient could advance our current understanding of the action of EMD. A recent study reported that both EMD and recombinant porcine amelogenin (rpAMEL) enhanced wound-fill rates in an in vitro wound model. Objective: To compare the effects of EMD and rpAmel on the proliferation and biosynthetic activity related to cytokines expressed by periodontal ligament cells in vitro. Methods: Proliferation assays were conducted in triplicate over an eight-day period treating immortalized human PDL cells with media or media supplemented with EMD, rpAmel at concentrations of 50mg/ml, 100mg/ml and 200 mg/ml. Cells were harvested and counted at 4, 6, and 8 days. Separately, cells treated with 100 mg/ml of EMD or rpAmel or media alone for 5 days were analyzed for expression levels of bone morphogenic protein (BMP –2, -4, -6), tissue growth factor-b1 (TGF-b1), and BMP receptors (ALK-3, ALK-2B) by semi-quantitative RT-PCR. Results: No significant enhancement of cell proliferation was observed in cells treated with EMD or Amel as compared to media alone (control). The PCR data, however, did reveal that EMD, but not Amel, up-regulated expression of BMP-2 and TGF-b in PDL cells. No appreciable up-regulation of ALK receptors was observed. Conclusions: A component of EMD other than Amel may be responsible for the increase in expression of BMP-2 and TGF-b1 which, in turn, may potentially stimulate periodontal tissue regrowth.