Comparative Study of the Chemotactic Responses of Periodontal Ligament Cells and Gingival Fibroblasts to Polypeptide Growth Factors

Abstract

Selective recruitment of periodontal ligament cells to a previously exposed root surface is believed to enhance periodontal regeneration. It has been hypothesized that competition from gingival fibroblasts may reduce the potential of periodontal regeneration. We compared the migratory responses of PDL cells and gingival fibroblasts to a variety of biologicals. Parallel experiments designed to examine the directed migration responses of both periodontal ligament cells (PDL cells) and gingival fibroblasts (GF) isolated from the same donors were conducted using Platelet Derived Growth Factor (PDGF), Insulin Like Growth Factor-I, -II (IGF-I, -II), Epidermal Growth Factor (EGF), Transforming Growth Factor-β (TGF-β), and the chemotactic factor derived from the conditioned culture media of PDL cells (termed PDL-CTX) as attractants. Both PDL cells and GF exhibited dose-dependent migratory responses when challenged with PDGF, IGF-I, IGF-II, EGF, and TGF-β. However, when these cells were challenged with PDL-CTX, only PDL cells migrated in a specific dose-dependent manner, while GF were refractive to PDL-CTX stimulation. Additionally, concentrated conditioned culture media from cultures of gingival fibroblasts did not stimulate PDL cell migratory responses. In other experiments, antibody directed against PDGF, FGF, TGF-β, IGF-I, IGF-II, NGF, and EGF did not inhibit the PDL-CTX-elicited response in PDL cells. Previous studies have suggested that success of periodontal therapy depends on the specific attachment, migration, and proliferation of selected periodontal ligament cells. The data presented in this manuscript suggest that both PDL cells and gingival fibroblasts respond to a multitude of growth factors. PDL-CTX was found to be PDL-cell-specific for directed migration. Thus, we conclude that any biological therapeutic regime for periodontal regeneration should include PDL-cell-specific agents.