Scaffold-Free Cell Pellet Transplantations Can Be Applied to Periodontal Regeneration

Cell transplantation has emerged as a novel therapeutic strategy for periodontitis, and the adoption of cell pellet offers advantages by secreting abundant extracellular matrix (ECM) and eliminating the adverse effect of cell carriers. This study aimed to fabricate scaffold-free periodontal ligament stem cell (PDLSC) pellets (MUCPs) and to evaluate their regeneration potential. We constructed monolayer cell pellets (MCPs) by fabricating and culturing multilayered cell sheets (MUCS) and constructed MUCPs from the MUCS. Immunochemistry, scanning electron microscope, real-time PCR, and Western blot analysis showed higher levels of COL-I, COL-III, fibronectin, and laminin in the MUCPs. Furthermore, the massive increase in ECM secretion improved cell adhesion, migration, and proliferation. Finally, upon transplantation into the omentum sac and periodontal defects, all the transplants formed regular aligned cementum/PDL-like complex, but the mineral deposit and fiber alignment were more obvious in the MUCPs than in the MCPs. Altogether, our results suggest that MUCPs may be a promising alternative to periodontal repair for future clinical application.