title: Characterization of genipin-modified dentin collagen.
abstract: Application of biomodification techniques to dentin can improve its biochemical and biomechanical properties. Several collagen cross-linking agents have been reported to strengthen the mechanical properties of dentin. However, the characteristics of collagen that has undergone agent-induced biomodification are not well understood. The objective of this study was to analyze the effects of a natural cross-linking agent, genipin (GE), on dentin discoloration, collagen stability, and changes in amino acid composition and lysyl oxidase mediated natural collagen cross-links. Dentin collagen obtained from extracted bovine teeth was treated with three different concentrations of GE (0.01%, 0.1%, and 0.5%) for several treatment times (0-24 h). Changes in biochemical properties of NaB(3)H4-reduced collagen were characterized by amino acid and cross-link analyses. The treatment of dentin collagen with GE resulted in a concentration- and time-dependent pigmentation and stability against bacterial collagenase. The lysyl oxidase-mediated trivalent mature cross-link, pyridinoline, showed no difference among all groups while the major divalent immature cross-link, dehydro-dihydroxylysinonorleucine/its ketoamine in collagen treated with 0.5% GE for 24 h, significantly decreased compared to control (P < 0.05). The newly formed GE-induced cross-links most likely involve lysine and hydroxylysine residues of collagen in a concentration-dependent manner. Some of these cross-links appear to be reducible and stabilized with NaB(3)H4.
authors.affiliation: Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nagaoka
authors.affiliation: NC Oral Health Institute, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nagaoka
authors.affiliation: Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Walter
authors.affiliation: Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Lee W
authors.initials: LW
authors.lastname: Boushell
authors.affiliation: Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Miguez
authors.affiliation: NC Oral Health Institute, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Burton
authors.affiliation: Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: André V
authors.initials: AV
authors.lastname: Ritter
authors.affiliation: NC Oral Health Institute, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Yamauchi
mesh_terms: D000818:Animals; D002417:Cattle; D024042:Collagen Type I / Q000737:chemistry*; D003804:Dentin / Q000737:chemistry*; D006901:Hydroxylysine; D007180:Incisor / Q000737:chemistry; D039823:Iridoids / Q000737:chemistry*; D008239:Lysine; D055550:Protein Stability; D014075:Tooth Discoloration
chemical_list: D024042:Collagen Type I; D039823:Iridoids; D006901:Hydroxylysine; C007834:genipin; D008239:Lysine