Cell-based tissue engineering strategies to regenerate the periodontium

Contains fulltext : 113031.pdf (publisher's version ) (Open Access)This thesis aims to provide further insight into the regeneration process of the periodontium. To achieve this purpose, two research strategies were used. First, the transplantation of PDL derived cells was investigated in an animal model. Second, a more fundamental approach was followed, i.e. developing in vitro model systems to understand the influence of mechano-topographical stimuli on PDL cell behaviour. The results from the in vivo cell implantation study suggest that the transplantation of PDL cells can favour periodontal regeneration in an indirect manner. It is indicated that PDL cells promote the osteogenic process by releasing stimulus factors, which affect the surrounding osteogenic cells. These paracrine effects are considered as a critical consequence, through which PDL cells induce superior tissue regeneration. In addition, the higher expression of gap-junctions in the implanted areas may be indicative of a more intense exchange of small messenger biomolecules between implanted PDL cells and surrounding host cells. In view of the fact that periodontium is a highly ordered tissue complex, and constantly under mechanical stimulus, we hypothesized that the mechano-topographical stimuli will take as much part in the reconstruction process as the mediating factors. Using our controlled 3D tissue culture model, we demonstrated that PDL cells realigned upon mechanical stimuli. The cells tended to shift their orientation always in favour of mechanical loading, even when they were cultured on a nano-patterned substrate surface to which the cells usually adapt their morphology at static condition. It is clear that current tissue engineering strategies holds promise to achieve full regeneration. However, before it is feasible for clinical application, a thorough understanding of underlying cellular processes in periodontal regeneration is required. The development of advanced cell culture systems, closely mimicking multiple aspects of the local environment of the tissue, can play an important role in achieving such understanding.Radboud Universiteit Nijmegen, 8 oktober 2013Promotor : Jansen, J.A. Co-promotores : Walboomers, X.F., Yang, F