Effects of enamel matrix proteins on multi-lineage differentiation of periodontal ligament cells in vitro.
ABSTRACT The adult periodontal ligament (PDL) is considered to contain progenitor cells that are involved in the healing of periodontal wounds. Treatment with enamel matrix derivative (EMD), a heat-treated preparation derived from enamel matrix proteins (EMPs), has been shown to be of some clinical benefit in eliciting periodontal regeneration in vivo. Although there is extensive information available about the effects of EMD on periodontal regeneration, the precise influence of this material on alveolar bone and the formation of blood vessels and proprioceptive sensory nerves, prominent features of functionally active periodontal tissue, remain unclear. The aim of the present study was therefore to examine the effects of EMD on the ability of human periodontal ligament cells (HPCs) to undergo multi-lineage differentiation in vitro. Our results showed that HPCs treated with EMD under non-selective growth conditions did not show any evidence of osteogenic, adipogenic, chondrogenic, neovasculogenic, neurogenic and gliogenic "terminal" differentiation. In contrast, under selective lineage-specific culture conditions, EMD up-regulated osteogenic, chondrogenic and neovasculogenic genes and "terminal" differentiation, but suppressed adipogenesis, neurogenesis and gliogenesis. These findings thus demonstrate for the first time that EMD can differentially modulate the multi-lineage differentiation of HPCs in vitro.
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ABSTRACT: Regeneration of periodontal structures is a complex challenge for periodontal wound healing. As by Wikesjö et al. in this issue, wound space provision, primary stability, and healing by primary intention serve as critical factors for attempts to regenerate the periodontium. Barrier membranes for space maintenance can be cumbersome to use in a clinical setting and have proven to provide only partial success in regenerative therapies. Not surprisingly, investigators and clinicians have started to search for biological molecules and cell technologies that could help to either speed up or modify the healing process that depends on migration and differentiation of several different cell populations. In this chapter, we will briefly review the technologies that are currently in use or in clinical trials. Readers are welcome to review in-depth publications for further details on this complex and evolving area of research. Adjunct growth factors in periodontal wound repair Over the years, a number of growth factors have been tested for periodontal regeneration. For true regeneration, four different tissues need to be regenerated, namely cementum, periodontal ligament (PDL), alveolar bone, and gingiva. In addition, this regeneration must happen in an environment where bacterial biofilms and mechanical forces are constantly challenging the wound healing process. The fact that so many different tissue types in the presence of a harsh environment are involved explains the lack of progress in perfecting regeneration, regardless of whether or not growth factors, differentiation factors or stem cell therapies are employed (see below). The number of growth factors, and cytokines that influence wound healing outcomes are numerous and need to act in a synchronized and concerted manner. Over the years, many of these growth factors have been tested in the regulation of periodontal ligament fibroblast function as well as in animal studies (reviewed in 1–3). At the present time, one commercial product containing growth factors is available for human use in periodontal defects (recombinant human Platelet-Derived Growth Factor-BB [rhPDGF-BB] with a beta-tricalcium phosphate scaffold [b-TCF]; GEM 21S ® ; Osteohealth) and two others are in clinical trials (Fibroblast Growth Factor-2 [FGF-2]; Growth/ Differentiation Factor-5 [GDF-5]) (Table 1).Endodontic Topics 01/2012; 26:18-40.