title: Dental pulp stem cells' secretome enhances pulp repair processes and compensates TEGDMA-induced cytotoxicity.
abstract: OBJECTIVE
  Aim of this study was to investigate the effects of dental pulp stem cells' (DPSCs) secretome, expressed through their culture conditioned medium (CM), on biological endpoints related to pulp repair and on TEGDMA-induced cytotoxicity.
  
  
  METHODS
  DPSCs cultures were established and characterized for stem cell markers with flow cytometry. CM was collected from DPSCs under serum deprivation conditions (SDC) and normal serum conditions (NSC) at various time-points. CM effects on DPSCs viability, migration and mineralization potential were evaluated by MTT assay, transwell insert and in vitro scratch assay and Alizarin Red staining/quantification respectively. TEGDMA (0.25-2.0mM) cytotoxicity regarding the same biological endpoints was tested in the presence/absence of CM. TGF-β1 and FGF-2 secretion in CM was measured by ELISA.
  
  
  RESULTS
  CM collected under SDC (4d) was able to increase cell viability by 20-25% and to reduce TEGDMA cytotoxicity by 20% (p<0.05). CM positive effects were not obvious when collected under NSC. Transwell assay showed significant increase (26%, p<0.05) of DPSCs' migration after CM exposure, whereas both migration assays could not support a migration rate improvement in TEGDMA-treated cultures exposed to CM compared to TEGDMA alone. CM significantly (p<0.01) increased DPSCs mineralization potential and completely counteracted TEGDMA cytotoxicity on this process. ELISA analysis showed a time-dependent increase of TGF-β1 and a TEGDMA concentration-dependent increase of both TGF-β1 and FGF-2 in CM.
  
  
  CONCLUSIONS
  These findings suggest that DPSCs secretome increases their viability, migration and mineralization potential and counteracts TEGDMA-induced cytotoxicy, revealing a novel mechanism of DPSCs autocrine signaling on pulp repair processes.
authors.affiliation: Department of Fixed Prosthesis & Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Paschalidis
authors.affiliation: Department of Fixed Prosthesis & Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
authors.forename: Athina
authors.initials: A
authors.lastname: Bakopoulou
authors.affiliation: Department of Fixed Prosthesis & Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
authors.forename: Polyxeni
authors.initials: P
authors.lastname: Papa
authors.affiliation: Department of Conservative Dentistry, Periodontology & Preventive Dentistry, School of Dentistry, Hannover Medical School, Hannover D-30625, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Leyhausen
authors.affiliation: Department of Conservative Dentistry, Periodontology & Preventive Dentistry, School of Dentistry, Hannover Medical School, Hannover D-30625, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Geurtsen
authors.affiliation: Department of Fixed Prosthesis & Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece. Electronic address: pkoidis@dent.auth.gr.
authors.forename: Petros
authors.initials: P
authors.lastname: Koidis
mesh_terms: D000293:Adolescent; D000880:Anthraquinones; D019898:Autocrine Communication / Q000502:physiology*; D002113:Calcification, Physiologic / Q000187:drug effects / Q000502:physiology; D018929:Cell Culture Techniques; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004396:Coloring Agents; D017077:Culture Media, Conditioned; D003764:Dental Materials / Q000633:toxicity*; D003782:Dental Pulp / Q000166:cytology* / Q000187:drug effects; D016222:Fibroblast Growth Factor 2 / Q000032:analysis; D006801:Humans; D011092:Polyethylene Glycols / Q000633:toxicity*; D011109:Polymethacrylic Acids / Q000633:toxicity*; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*; D013778:Tetrazolium Salts; D013844:Thiazoles; D053773:Transforming Growth Factor beta1 / Q000032:analysis
chemical_list: D000880:Anthraquinones; D004396:Coloring Agents; D017077:Culture Media, Conditioned; D003764:Dental Materials; D011109:Polymethacrylic Acids; D013778:Tetrazolium Salts; D013844:Thiazoles; D053773:Transforming Growth Factor beta1; D016222:Fibroblast Growth Factor 2; C020946:triethylene glycol dimethacrylate; C004468:Alizarin Red S; D011092:Polyethylene Glycols; C022616:thiazolyl blue
keywords: Autocrine/paracrine signaling; Conditioned-medium (CM); Dental pulp stem cells (DPSCs); Pulp repair; TEGDMA