Cellular uptake and processing of enamel matrix derivative by human periodontal ligament fibroblasts

Objective

Enamel matrix derivative (EMD), is an extract of porcine developing enamel matrix. Its commercialised form Emdogain, is claimed to stimulate periodontal regeneration by recapitulating original developmental processes, although the mechanism remains unclear. Our objective was to investigate interactions between EMD and human periodontal ligament (HPDL) fibroblasts in vitro.

Design

HPDL fibroblasts were cultured in the presence of fluorescently labelled EMD and cellular EMD uptake was monitored using confocal laser scanning microscopy and immunohistochemistry. Internalised EMD proteins were characterised using SDS-PAGE.

Results

EMD was internalised by HPDL fibroblasts leading to the appearance of multiple, vesicle-like structure in the cytoplasm. The internalised protein was composed mainly of the major 20 kDa amelogenin component of EMD which was subsequently processed with time to generate a cumulative 5 kDa component.

Conclusions

Cellular uptake and subsequent intracellular processing of EMD components by dental mesenchymal cells may play a role in EMD bioactivity and in part explain the turnover of Emdogain when placed clinically.