Hydroxyapatite-collagen composites. Part I: Can the decrease of the interactions between the two components be a physicochemical component of osteoporosis in aged bone?

Dipartimento di Ingegneria Chimica, Chimica Industriale e Scienza dei Materiali, Università di Pisa, Largo Lucio Lazzarino, 56122, Pisa, Italy.
Journal of Materials Science Materials in Medicine (Impact Factor: 2.59). 03/2011; 22(3):637-46. DOI: 10.1007/s10856-011-4238-2
Source: PubMed


The interactions of Type I acid soluble collagen (Col) with both carbonate-free hydroxyapatite (HA(1100)) and carbonate-rich one (CHA) were investigated. The aim was to ascertain whether the increase of bone CO(3) (2-) with ageing could relate to the disease known as osteoporosis. HA(1100)-Col and CHA-Col composites with various ratios were prepared and examined. Scanning electron microscopy and differential scanning calorimetry showed a stronger adhesion of the Col matrix to the granules of HA(1100) than to those of CHA. FT-IR spectroscopy showed that with HA(1100) both multiple hydrogen bonds of Col peptide -NH groups with HA PO(4) (3-), and electrochemical interactions between Col peptide -C=O groups and HA Ca(2+) were present. In the presence of CO(3) (2-), the interactions between -NH and phosphate were diminished, and Ca(2+) interacted more strongly with CO(3) (2-) than with peptide -C=O, so causing a separation between the two components of the bone extra-cellular matrix. The results obtained strengthen the hypothesis that the substitution of PO(4) (3-) ions by CO(3) (2-) ions in the HA lattice might be a significant component of osteoporosis, although further investigation is needed.

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Available from: Giulio Dante Guerra, Dec 30, 2014
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    • "The use of imidazolyl and 2-methyl-imidazolyl CHI for bone lesion healing was tested on sheep femoral condyles [38]. A particularly interesting feature was the use of CHI and its derivatives for the treatment of osteoporosis, a possible physicochemical component which was recently studied by the authors' group [39]. The release, as a consequence of CHI biodegradation, of the bone morphogenetic protein BMP-7 (OP-1), linked to an N,N-dicarboxymethyl CHI matrix in the form of a polyelectrolyte complex, was tested on the femoral condyles of four female osteoporotic rats. "
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    ABSTRACT: The use of materials, containing the biocompatible and bioresorbable biopolymer poly(1→4)-2-amino-2-deoxy-β-D-glucan, containing some N-acetyl-glucosamine units (chitosan, CHI) and/or its derivatives, to fabricate devices for the regeneration of bone, cartilage and nerve tissue, was reviewed. The CHI-containing devices, to be used for bone and cartilage regeneration and healing, were tested mainly for in vitro cell adhesion and proliferation and for insertion into animals; only the use of CHI in dental surgery has reached the clinical application. Regarding the nerve tissue, only a surgical repair of a 35 mm-long nerve defect in the median nerve of the right arm at elbow level with an artificial nerve graft, comprising an outer microporous conduit of CHI and internal oriented filaments of poly(glycolic acid), was reported. As a consequence, although many positive results have been obtained, much work must still be made, especially for the passage from the experimentation of the CHI-based devices, in vitro and in animals, to their clinical application.
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