Effects of soluble cobalt and cobalt incorporated into calcium phosphate layers on osteoclast differentiation and activation

Somying Patntirapong, Pamela Habibovic, Peter V. Hauschka*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Metal ions Originating from mechanical debris and Corrosive wear of prosthetic implant alloys accumulate in peri-implant soft tissues, bone mineral, and body fluids. Eventually, metal ions such as cobalt (II) (Co2+) which is a major component of cobalt-chromium-based implant alloys and a known activator of osteolysis, are incorporated into the mineral phase of bone. We hypothesize that the accumulation of CO2+ in the mineral could directly activate osteolysis by targeting osteoclasts. To test this hypothesis, we coated tissue culture plastic with a thin layer of calcium phosphate (CaP) containing added traces Co2+ thereby mimicking the bone mineral accumulation of Co2+. Murine bone marrow osteoclasts formed in the presence of M-CSF and RANKL were cultured on these surfaces to examine the effects of Co2+ on osteoclast formation and resorptive activity. Treatment conditions with Co2+ involved incorporation into the Cap layer, adsorption to the mineral Surface, or addition to Culture media. Micromolar concentrations of Co2+ delivered to developing osteoclast Precursors by all 3 routes increased both osteoclast differentiation and resorptive function. Compared to CaP layers without Co2+, we observed a maximal 75% increase in osteoclast numbers and a 2.3- to 2.7-fold increase in mineral resorption from the tissue culture wells containing 0.1 mu m Co2+ and 0.1 - 10 mu m Co2+, respectively. These concentrations are well within the range found in peri-implant tissues in vivo. This direct effect of Co2+ on osteoclasts appears to act independently of the particulate phagocytosis/inflammation-mdiated pathways, thus enhancing osteolysis and aseptic implant loosening. (C) 2008 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)548-555
Number of pages8
JournalBiomaterials
Volume30
Issue number4
DOIs
Publication statusPublished - Feb 2009
Externally publishedYes

Keywords

  • Calcium phosphate coating
  • Cobalt alloy
  • Hypoxia
  • Joint replacement
  • Osteoclast
  • Osteolysis
  • RESISTANT ACID-PHOSPHATASE
  • TOTAL HIP-ARTHROPLASTY
  • METAL-ION LEVELS
  • IN-VITRO
  • WEAR PARTICLES
  • C-FMS
  • CORROSION
  • CELLS
  • SURFACE
  • TISSUE

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