Characterization of cells derived from inflamed intra-bony periodontal defects

Introduction: Regeneration of intra-bony periodontal defects should be supported by formation of new blood vessels and nerve fibres to ensure nutrition and innervation of the newly formed tissues. Aim of the present study was to evaluate the neurovascular properties of human stem cells derived from inflamed periodontal ligaments (ihPDLSCs). Methods: Cultures of ihPDLSCs were established from granulation tissue of intra-bony periodontal defects (n = 4). Expression of epitopes characteristic for mesenchymal (CD73, CD90, CD105, CD146, STRO-1), embryonic (SSEA-4) and hematopoietic (CD34, CD45) stem cells were analysed by flow cytometry. Neuronal, endothelial and osteoblastic differentiation was induced by respec-tive media. Changes in cell morphology were observed microscopically. Matrix mineralization was visualized and quantified using Alizarin Red S staining. Gene expression of neurogenic (NEFL, NCAM1, ENO2, TUBB3), angiogenic (VEGFR1, VEGFR2, PECAM1, ANGPT2) and osteogenic (RUNX2, SP7, APL, BMP2, BGLAP, SPP1, IBSP) markers was assessed by qRT-PCR. Results: Cultures of ihPDLSCs showed high expression of CD73 and CD90, medium to high expression of CD105 and CD146, low to medium expression of SSEA-4 and low expression of STRO-1, CD34 and CD45. Trilineage differentiation potential was documented by histomorphologic changes, pronounced matrix mineralization and significant upregulation of stage-specific markers characteristic for neuronal (NEFL, NCAM1, ENO2), endothelial (VEGFR1, VEGFR2, PECAM1) and osteoblastic (ALP, BMP2) differentiation. Conclusions: Our data provide evidence that cells isolated from granulation tissue of intra-bony periodontal defects have properties characteristic for mesenchymal stem cells. As these cells have the potential to undergo neuronal, endothelial and osteoblastic differentiation, the preservation of granulation tissue during regenerative periodontal surgery may be valuable to promote the healing of intra-bony periodontal defects. Keywords: granulation tissue, in vitro, inflamed intra-bony defects, mesenchymal stem cells, regenerative periodontal surgery, trilineage differentiation potential