title: Prostaglandin EP4 receptor agonist augments fixation of hydroxyapatite-coated implants in a rat model of osteoporosis.
abstract: The reduced stability of hydroxyapatite (HA)-coated implants in osteopenic conditions is considered to be a major problem. We therefore developed a model of a boosted cementless implantation in osteopenic rats.Twelve-week-old rats were either ovariectomised (OVX) or sham-operated (SO), and after 24 weeks plain or HA-coated implants were inserted. They were treated with either a prostaglandin EP4 receptor agonist (ONO-4819) or saline for one month. The EP4 agonist considerably improved the osteoporosis in the OVX group. Ultrastructural analysis and mechanical testing showed an improvement in the implant-bone attachment in the HA-coated implants, which was further enhanced by the EP4 agonist. Although the stability of the HA-coated implants in the saline-treated OVX rats was less than in the SO normal rats, the administration of the EP4 agonist significantly compensated for this shortage. Our results showed that the osteogenic effect of the EP4 agonist augmented the osteoconductivity of HA and significantly improved the stability of the implant-bone attachment in the osteoporotic rat model.
authors.affiliation: Department of Orthopaedic Surgery, Orthopaedic Research Laboratory, Hara Doi Hospital, 6-4-8 Aoba, Fukuoka 8138588, Japan. khayashi2jp@yahoo.co.jp
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.forename: A
authors.initials: A
authors.lastname: Fotovati
authors.forename: S A
authors.initials: SA
authors.lastname: Ali
authors.forename: K
authors.initials: K
authors.lastname: Oda
authors.forename: H
authors.initials: H
authors.lastname: Oida
authors.forename: M
authors.initials: M
authors.lastname: Naito
mesh_terms: D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D015519:Bone Density / Q000187:drug effects; D020099:Coated Materials, Biocompatible; D004195:Disease Models, Animal; D017886:Durapatite; D005260:Female; D005269:Femur / Q000187:drug effects / Q000503:physiopathology / Q000648:ultrastructure; D006537:Heptanoates / Q000627:therapeutic use*; D016348:Osseointegration / Q000187:drug effects; D010024:Osteoporosis / Q000150:complications / Q000188:drug therapy*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D018078:Receptors, Prostaglandin E / Q000819:agonists*; D058309:Receptors, Prostaglandin E, EP4 Subtype
chemical_list: D020099:Coated Materials, Biocompatible; D006537:Heptanoates; C487764:ONO4819; C545652:Ptger4 protein, rat; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; D017886:Durapatite