title: Zoledronate but not denosumab suppresses macrophagic differentiation of THP-1 cells. An aetiologic model of bisphosphonate-related osteonecrosis of the jaw (BRONJ).
abstract: OBJECTIVE
  Bisphosphonates and denosumab are antiresorptive drugs used for the treatment of osteoporosis and oncological tumors. A severe side effect is osteonecrosis of the jaw. Monocyte/macrophage dysfunction is considered to play a distinct role in osteonecrosis. THP-1 monocytic cells were used in this study to elucidate the influence of zoledronate and denosumab on phorbol-12-myrisate-13-acetate (PMA)-induced macrophage differentiation and function in real-time.
  
  
  METHODS
  Macrophagic differentiation of the THP-1 suspension cells was measured by cell adherence in the presence or absence of different concentrations of zoledronate (0.5, 5, 50 μM) and denosumab (1, 10, 20, 40 μg/mL) using the real-time xCELLigence system. Additionally, a live/dead staining was performed by fluorescence microscopy.
  
  
  RESULTS
  THP-1 cells demonstrated a regular initial PMA-induced differentiation to macrophages by live measurements of cell adherence and by an increase in CD68 surface expression as detected by flow cytometry. The addition of zoledronate led to cell detachment of the THP-1-derived macrophages in a dose-dependent manner in contrast to denosumab. Cell detachment was based on cell death as confirmed by live/dead staining, revealing elevated numbers of dead cells following addition of high zoledronate concentrations. However, denosumab did not deteriorate THP-1 cell viability.
  
  
  CONCLUSIONS
  Our results demonstrate that zoledronate but not denosumab suppresses monocytic THP-1 cell viability after macrophagic differentiation dose-dependently.
  
  
  CONCLUSIONS
  This is the first real-time study providing evidence for a dose-dependent immunosuppressive effect of zoledronate in contrast to denosumab on local macrophages.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Tuebingen, Osianderstrasse 2-8, 72076, Tuebingen, Germany, sebastian.hoefert@med.uni-tuebingen.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hoefert
authors.forename: Claudia Sade
authors.initials: CS
authors.lastname: Hoefert
authors.forename: Marc
authors.initials: M
authors.lastname: Albert
authors.forename: Adelheid
authors.initials: A
authors.lastname: Munz
authors.forename: Martin
authors.initials: M
authors.lastname: Grimm
authors.forename: Hinnak
authors.initials: H
authors.lastname: Northoff
authors.forename: Siegmar
authors.initials: S
authors.lastname: Reinert
authors.forename: Dorothea
authors.initials: D
authors.lastname: Alexander
mesh_terms: D059266:Bisphosphonate-Associated Osteonecrosis of the Jaw / Q000209:etiology*; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D000069448:Denosumab / Q000008:administration & dosage / Q000494:pharmacology*; D004164:Diphosphonates / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D000074084:THP-1 Cells; D000077211:Zoledronic Acid
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; D000069448:Denosumab; D000077211:Zoledronic Acid