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Investigation of the Molecular Nature of Low-molecular-mass Cobalt(II) Ions in Isolated Osteoarthritic Knee-joint Synovial Fluid |
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| Authors: | Christopher JL Silwood Ian C Chikanza K Elizabeth Tanner Julia C Shelton John G Bowsher Martin Grootveld |
| Institution: | 1. Department of Applied Science, London South Bank University, 103 Borough Road, SEAA, 1 0, London, UKgrootum@isbu.ac.uk;3. Bone and Joint Research Unit, Barts and The London, Queen Mary's School of Medicine and Dentistry, John Vane Science Centre, Charterhouse Square, EC1M 6BQ, London, UK;4. Interdisciplinary Research Centre in Biomedical Materials, Queen Mary University of London, Mile End Road, ENS, 1 4, London, UK;5. Department of Applied Science, London South Bank University, 103 Borough Road, SEAA, 1 0, London, UK |
| Abstract: | High field 1H NMR spectroscopy demonstrated that addition of Co(II) ions to osteoarthritic knee-joint synovial fluid (SF) resulted in its complexation by a range of biomolecules, the relative efficacies of these complexants/chelators being citrate ? histidine ～ threonine?glycine ～ glutamate ～ glutamine ～ phenylalanine ～ tyrosine > formate > lactate?alanine > valine > acetate > pyruvate > creatinine, this order reflecting the ability of these ligands to compete for the available Co(II) in terms of (1) thermodynamic equilibrium constants for the formation of their complexes and (2) their SF concentrations. Since many of these SF Co(II) complexants (e.g. histidinate) serve as powerful ?OH scavengers, the results acquired indicate that any of this radical generated from the Co(II) source in such complexes via Fenton or pseudo-Fenton reaction systems will be “site-specifically” scavenged. The significance of these observations with regard to cobalt toxicity and the in vivo corrosion of cobalt-containing metal alloy joint prostheses (e.g. CoCr alloys) is discussed. |
| Keywords: | Low-molecular-mass cobalt ions Osteoarthritis 1H NMR Speciation Synovial fluid CoCr metal alloy joint prostheses |