Platelet rich plasma enhances osteoconductive properties of a hydroxyapatite-β-tricalcium phosphate scaffold (Skelite™) for late healing of critical size rabbit calvarial defects

11siThe use of platelet rich plasma (PRP) in bone repair remains highly controversial. In this work, we evaluated the effect of lyophilized PRP on bone regeneration when associated with a silicon stabilized hydroxyapatite tricalcium phosphate scaffold in a rabbit calvarial defect (Skelite™). Critical defects were created in the calvaria of twenty-four rabbits. The periosteum was removed and the defects were either left empty or filled with allogeneic PRP gel; Skelite particles; Skelite and PRP gel. Four animals were killed after 4 weeks, 10 animals after 8 and 10 after 16 weeks. Specimens were processed for X-ray microtomography (μCT) and for resin embedded histology. μCT analysis revealed significant osteoid-like matrix and new bone deposition in PRP + Skelite group at both 8 and 16 weeks in respect to Skelite alone. Histologically, PRP + Skelite defects were highly cellular with more abundant osteoid deposition and more regular collagen fibres. Moreover, in vitro migration assays confirmed the chemotactic effect of PRP to endothelial and osteoprogenitor cells. We conclude that the addition of PRP influenced the local tissue microenvironment by providing key cryptic factors for regeneration, thereby enhancing progenitor cell recruitment, collagen and bone matrix deposition, and by creating a bridging interface between the scaffold and bone.nonenoneEl Backly, Rania M.; Zaky, Samer H.; Canciani, Barbara; Saad, Manal M.; Eweida, Ahmed M.; Brun, Francesco; Tromba, Giuliana; Komlev, Vladimir S.; Mastrogiacomo, Maddalena; Marei, Mona K.; Cancedda, RanieriEl Backly, Rania M.; Zaky, Samer H.; Canciani, Barbara; Saad, Manal M.; Eweida, Ahmed M.; Brun, Francesco; Tromba, Giuliana; Komlev, Vladimir S.; Mastrogiacomo, Maddalena; Marei, Mona K.; Cancedda, Ranier

Influence of Poly-L-Lactic Acid Scaffold's Pore Size on the Proliferation and Differentiation of Dental Pulp Stem Cells

The aim of this study was to evaluate the influence of the poly-L-lactic acid (PLLA)- based scaffold’s pore size on the proliferation and differentiation of dental pulp stem cells (DPSCs). The scaffolds were prepared in pulp chambers of 1-mm-thick tooth slices from third molars using salt crystals (150-250 μm or 251-450 μm) as porogen. DPSC (1x105 cells) were seeded in the scaffolds with different pore sizes, and cultured in 24-well plates. The cell proliferation was evaluated using the WST-1 assay after 3-21 days. Furthermore, RT-PCR was used to assess the differentiation of the DPSCs into odontoblasts, using markers of odontoblastic differentiation (DSPP, DSP-1 and MEPE). RNA from human odontoblasts was used as control. Cell proliferation rate was similar in both scaffolds except at the 14th day period, in which the cells seeded in the scaffolds with larger pores showed higher proliferation (p<0.05). After 21 days DPSCs seeded in both evaluated scaffolds were able of expressing odontoblastic markers DMP-1, DSPP and MEPE. In summary, both scaffolds tested in this study allowed the proliferation and differentiation of DPSCs into odontoblast-like cells.O objetivo desse estudo foi avaliar a influência do tamanho dos poros de um scaffold à base de poli ácido láctico (PLLA) sobre a proliferação e diferenciação de células tronco da polpa dental (dental pulp stem cells - DPSC). Os scaffolds foram preparados dentro da câmara pulpar de discos de terceiros molares (1 mm), utilizando sal como porógeno (150-250 μm ou 251-450 μm). DPSC (1x105 células) foram semeadas nos scaffolds com diferentes tamanhos de poros e cultivadas em placas de 24 poços. A proliferação celular foi avaliada utilizando WST-1 após 3-21 dias. Além disso, RT-PCR foi utilizado para avaliar a diferenciação odontoblástica das DPSC utilizando marcadores da diferenciação odontoblástica (DSPP, DMP-1 e MEPE). RNA obtido de odontoblastos humanos foi utilizado como controle. A taxa de proliferação celular foi semelhante nos dois scaffolds avaliados, exceto no 14° dia, no qual as células cultivadas nos scaffolds com os maiores poros apresentaram uma maior taxa de proliferação (p<0,05). Após 21 dias, as DSPC cultivadas em ambos scaffolds avaliados foram capazes de expressar os marcadores odontoblásticos DMP-1, DSPP e MEPE. Em resumo, ambos scaffolds avaliados nesse estudo permitiram a proliferação e diferenciação odontoblástica das DPSC