title: Effect of modification of hydroxyapatite/collagen composites with sodium citrate, phosphoserine, phosphoserine/RGD-peptide and calcium carbonate on bone remodelling.
abstract: This study describes the early interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (HA/Coll) and its modifications with sodium citrate (CI), calcium carbonate (CA), phosphoserine (P) and phosphoserine plus RGD-peptide (RGD). Cylindrical implants of HA/Coll and its modifications were inserted into the tibia of Wistar rats. We analysed 6 specimens per group at days 2, 4, 7, 14 and 28. CI, P and RGD modifications showed improved material properties (finer microstructure and higher compressive strength) compared to CA and HA/Coll implants. The powder X-ray diffraction (XRD) showed that the addition of P and CI led to an increase of alpha-TCP peaks while the diffraction patterns of the non-modified cement (HA/Coll) were quite similar with that of natural bone. All of the implants healed without adverse reactions. A significantly higher number of TRAP-positive osteoclasts were observed around CI, RGD and P on day 7 compared to CA and HA/Coll. Around CI, P and RGD a significantly delayed increase of ED1-positive mononuclear cells was detected. The amount of direct bone contact after 28 days was significantly higher around CI, P and RGD compared to CA and HA/Coll implants. The addition of CI, P and RGD appears to enhance bone remodelling at the early stages of bone healing, leading to increased bone formation around HA/Coll composite cements.
authors.affiliation: Department of Trauma and Reconstructive Surgery, University Hospital Carl Gustav Carus, Fetscherstrasse 74, 01307 Dresden, Germany. schneidersw@gmx.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schneiders
authors.forename: Antje
authors.initials: A
authors.lastname: Reinstorf
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Pompe
authors.forename: Rene
authors.initials: R
authors.lastname: Grass
authors.forename: Achim
authors.initials: A
authors.lastname: Biewener
authors.forename: Michael
authors.initials: M
authors.lastname: Holch
authors.forename: Hans
authors.initials: H
authors.lastname: Zwipp
authors.forename: Stefan
authors.initials: S
authors.lastname: Rammelt
mesh_terms: D000818:Animals; D001843:Bone Cements / Q000737:chemistry* / Q000494:pharmacology*; D016723:Bone Remodeling / Q000187:drug effects*; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology; D002119:Calcium Carbonate; D002951:Citrates; D024042:Collagen Type I; D017886:Durapatite; D066298:In Vitro Techniques; D008297:Male; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009842:Oligopeptides; D016348:Osseointegration / Q000187:drug effects; D010768:Phosphoserine; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D000077559:Sodium Citrate; D013977:Tibia / Q000473:pathology / Q000601:surgery
chemical_list: D001843:Bone Cements; D018786:Bone Substitutes; D002951:Citrates; D024042:Collagen Type I; D009842:Oligopeptides; D010768:Phosphoserine; D000077559:Sodium Citrate; C047981:arginyl-glycyl-aspartic acid; D017886:Durapatite; D002119:Calcium Carbonate