Investigation of the molecular nature of low-molecular-mass cobalt(II) ions in isolated osteoarthritic knee-joint synovial fluid.
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.
Silwood
Christopher J L
CJ
Department of Applied Science, London South Bank University, 103 Borough Road, London SE1 0AA, UK.
Chikanza
Ian C
IC
Tanner
K Elizabeth
KE
Shelton
Julia C
JC
Bowsher
John G
JG
Grootveld
Martin
M
D003035:Cobalt / Q000032:analysis* / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D017665:Hydroxyl Radical / Q000737:chemistry; D007719:Knee Joint; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008875:Middle Aged; D008970:Molecular Weight; D010003:Osteoarthritis / Q000378:metabolism*; D013582:Synovial Fluid / Q000737:chemistry*
D016166:Free Radical Scavengers; D017665:Hydroxyl Radical; D003035:Cobalt