title: Anti-inflammatory effects of EMD in the presence of biomechanical loading and interleukin-1β in vitro.
abstract: Enamel matrix derivative (EMD) used to promote periodontal regeneration has been shown to exert anti-inflammatory effects. This in vitro study was performed to investigate if the anti-inflammatory actions of EMD are modulated by the local cellular environment, such as inflammation or occlusal, i.e., biomechanical, loading. Human periodontal ligament cells were seeded on BioFlex plates and incubated with EMD under normal, inflammatory, and biomechanical loading conditions for 1 and 6 days. In order to mimic inflammatory and biomechanical loading conditions in vitro, cells were stimulated with interleukin (IL)-1β and exposed to dynamic tensile strain, respectively. The gene expression of IL-1β, IL-1 receptor antagonist (IL-1RN), IL-6, IL-8, IL-10, and cyclooxygenase (COX)-2 was analyzed by real-time RT-PCR and the IL-6 protein synthesis by enzyme-linked immunoassay. For statistical analysis, Student's t test, ANOVA, and post-hoc comparison tests were applied (p < 0.05). EMD downregulated significantly the expression of IL-1β and COX-2 at 1 day and of IL-6, IL-8, and COX-2 at 6 days in normal condition. In an inflammatory environment, the anti-inflammatory actions of EMD were significantly enhanced at 6 days. In the presence of low biomechanical loading, EMD caused a downregulation of IL-1β and IL-8, whereas high biomechanical loading significantly abrogated the anti-inflammatory effects of EMD at both days. Neither IL-1RN nor IL-10 was upregulated by EMD. These data suggest that high occlusal forces may abrogate anti-inflammatory effects of EMD and should, therefore, be avoided immediately after the application of EMD to achieve best healing results.
authors.affiliation: Clinical Research Unit 208, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany.
authors.forename: Marjan
authors.initials: M
authors.lastname: Nokhbehsaim
authors.forename: Birgit
authors.initials: B
authors.lastname: Deschner
authors.forename: Jochen
authors.initials: J
authors.lastname: Winter
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
authors.forename: Andreas
authors.initials: A
authors.lastname: Jäger
authors.forename: Søren
authors.initials: S
authors.lastname: Jepsen
authors.forename: James
authors.initials: J
authors.lastname: Deschner
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001696:Biomechanical Phenomena; D001732:Bite Force; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000032:analysis; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D015536:Down-Regulation; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000032:analysis; D016753:Interleukin-10 / Q000032:analysis; D053583:Interleukin-1beta / Q000032:analysis / Q000276:immunology*; D015850:Interleukin-6 / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D000893:Anti-Inflammatory Agents; C508606:CXCL8 protein, human; D003746:Dental Enamel Proteins; C508609:IL10 protein, human; C507763:IL1RN protein, human; C508600:IL6 protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; C109069:enamel matrix proteins; D016753:Interleukin-10; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human