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Fetuin and osteocalcin interact with calcospherite formation during the calcification process of poly(2‐hydroxyethylmethacrylate) in vitro : a Raman microspectroscopic monitoring
Author(s) -
Libouban H.,
Filmon R.,
Mauréac A.,
Baslé M. F.,
Chappard D.
Publication year - 2009
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2272
Subject(s) - fetuin , raman spectroscopy , chemistry , osteocalcin , immunogold labelling , calcification , biophysics , crystallography , biochemistry , glycoprotein , alkaline phosphatase , ultrastructure , anatomy , biology , medicine , physics , optics , enzyme
Abstract Calcification is a complex process implying numerous proteins acting as nucleators, ion transporters and crystal growth regulators. Several proteins impair mineralization, such as fetuin and osteocalcin [(bone Gla protein), BGP]. We have evaluated their effets on the biomimetic calcification of carboxymethylated poly(2‐hydroxyethyl methacrylate). Polymer pellets were incubated in synthetic body fluid for 4 days at 37 °C to induce nucleation. They were transferred for 11 days in a fresh medium containing fetuin (5 mg/ml) or BGP (1 mg/ml) or a combination of boths. Pellets were examined by scanning and transmission electron microscopy. Detection of proteins was done by immunogold and Raman microspectroscopy. Calcospherites were dissolved, Ca and P were dosed. BGP did not modify the amount of CaP or the Ca/P ratio, but the mean size of calcospherites was two times larger than controls. Fetuin reduced the number of calcospherites and the amount of CaP but increased the Ca/P ratio. CaP deposition was reduced on pellets incubated with both proteins, and calcospherites appeared considerably smaller. Immunogold and Raman spectroscopy identified both proteins adsorbed on hydroxyapatite (HA) tablets. Noncollagenous proteins control HA crystal growth in a different manner. The interaction between fetuin and BGP reduced the amount of calcified material deposited but also affected the morphology of the calcospherites. Copyright © 2009 John Wiley & Sons, Ltd.