title: The effects of human platelet lysate on dental pulp stem cells derived from impacted human third molars.
abstract: Human platelet lysate (PL) has been suggested as a substitute for fetal bovine serum (FBS) in the large-scale expansion of dental pulp stem cells (DPSCs). However, the biological effects and the optimal concentrations of PL for the proliferation and differentiation of human DPSCs remain unexplored. We isolated and expanded stem cells from the dental pulp of extracted third molars and evaluated the effects of PL on the cells' proliferative capacity and differentiation potential in vitro and in vivo. Before testing, immunocytochemical staining and flow cytometry-based cell sorting showed that the cells derived from human dental pulp contained mesenchymal stem cell populations. Cells were grown on tissue culture plastic or on hydroxyapatite-tricalcium phosphate (HA/TCP) biomaterials and were incubated with either normal or odontogenic/osteogenic media in the presence or absence of various concentrations of human PL for further investigation. The proliferation of DPSCs was significantly increased when the cells were cultured in 5% PL under all testing conditions (P < 0.05). However, this enhancement was inconsistent when the cells were cultured in 1% PL or in 10% PL; 10% PL significantly inhibited cell proliferation and was therefore excluded from further differentiation testing. Culture medium containing 5% PL also significantly promoted the mineralized differentiation of DPSCs, as indicated by the measurement of alkaline phosphatase activity and calcium deposition under mineral-conditioned media (P < 0.05). Scanning electron microscopy and modified Ponceau trichrome staining showed that the cells treated with 5% PL and mineralizing media were highly capable of integrating with the HA/TCP biomaterials and had fully covered the surface of the scaffold with an extensive sheet-like structure 14 d after seeding. In addition, 5% PL showed significantly positive effects on tissue regeneration in two in vivo transplantation models. We conclude that the appropriate concentration of PL enhances the proliferation and mineralized differentiation of human DPSCs both in vitro and in vivo, which supports the use of PL as an alternative to FBS or a nonzoonotic adjuvant for cell culture in future clinical trials. However, the elucidation of the molecular complexity of PL products and the identification of both the essential growth factors that determine the fate of a specific stem cell and the criteria to establish dosing require further investigation.
authors.affiliation: Department of Operative Dentistry & Endodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi 710032, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.forename: Hai-Hua
authors.initials: HH
authors.lastname: Sun
authors.forename: Han-Guo
authors.initials: HG
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Kong
authors.forename: Fa-Ming
authors.initials: FM
authors.lastname: Chen
authors.forename: Qing
authors.initials: Q
authors.lastname: Yu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001672:Biocompatible Materials; D001792:Blood Platelets / Q000166:cytology*; D002454:Cell Differentiation; D019070:Cell Lineage; D002478:Cells, Cultured; D003470:Culture Media; D003782:Dental Pulp / Q000166:cytology* / Q000648:ultrastructure; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third / Q000166:cytology* / Q000648:ultrastructure; D013234:Stem Cells / Q000166:cytology* / Q000648:ultrastructure
chemical_list: D001672:Biocompatible Materials; D003470:Culture Media; D000469:Alkaline Phosphatase