Comparative Effects of Concentrated Growth Factors on the Biological Characteristics of Periodontal Ligament Cells and Stem Cells from Apical Papilla

During cell-free regenerative endodontic therapy, both stem cells from apical papilla (SCAPs) and periodontal ligament cells (PDLCs) are possible cell sources because of their proximity. Nonetheless, the regenerative ability of PDLCs and SCAPs under the induction of concentrated growth factors (CGFs) remains unclear.PDLCs and SCAPs were treated with various concentrations of CGF-conditioned medium (CCM). The effects of CCM with or without Porphyromonas gingivalis lipopolysaccharide (LPS) on cell migration, odonto/osteogenic differentiation, and the expression of inflammatory cytokines were assessed. Dentin matrix transplants composed of PDLCs or SCAPs cell sheets coupled with CGF were put subcutaneously in immunocompromised mice for 8 weeks to explore their regenerative characteristics in vivo.CCM dose dependently enhanced the migration, proliferation, and odonto/osteogenic differentiation of PDLCs and SCAPs. CCM alleviated LPS-inhibited odonto/osteogenic differentiation of PDLCs and SCAPs as well as the LPS-induced up-regulation of inflammatory cytokines. In vivo, the newly regenerated tissue and microvessels formed by PDLCs and SCAPs were significantly increased under the induction of CGF. SCAPs mainly regenerated pulp/dentinlike tissues and a large number of microvessels, whereas PDLCs mainly formed bone/cementumlike structures.Overall, PDLCs excelled in cell proliferation, migration, and osteogenic differentiation, whereas SCAPs outperformed PDLCs in terms of angiogenic and odontogenic differentiation. The biological differences between PDLCs and SCAPs provided a possible theoretical basis for the formation of bone/cementum/periodontal ligament-like tissues after cell-free regenerative endodontic therapy.