title: Effect of partial hydrolysis of octacalcium phosphate on its osteoconductive characteristics.
abstract: The present study was designed to investigate whether the stoichiometry of octacalcium phosphate OCP affects its osteoconductive and immune response characteristics in rat bone marrow. Those characteristics of synthetic, well-grown OCP but with a non-stoichiometric composition were compared with those of a slightly hydrolyzed OCP (low crystalline OCP: LC-OCP), the fully hydrolyzed apatitic product of OCP or biodegradable beta-tricalcium phosphate (beta-TCP) ceramic, by their implantation in rat tibia for 56 days. The physicochemical aspect of implants and biological responses were analyzed by X-ray diffraction, histomorphometry, immunohistochemistry and expression of mRNA around the implants. The remarkable findings were that: (1) the highest bone formation rate was obtained for beta-TCP whereas the lowest for LC-OCP at Day 14; (2) the rates were reversed and reached the highest for LC-OCP until Day 56; (3) the early expression of ostoeoclast markers TRAP and cathepsin-K was suppressed with LC-OCP; (4) the expression of inflammatory markers IL-beta1 and TNF-alpha was suppressed with LC-OCP. The results confirmed that the partially hydrolyzed OCP with Ca/P molar ratio 1.37 (LC-OCP) enhances bone formation most, suppressing early osteoclast activity and reducing inflammation.
authors.affiliation: Department of Orthopedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seriyo-machi, Aoba-ku, Sendai 980-8574, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Miyatake
authors.forename: Koshi N
authors.initials: KN
authors.lastname: Kishimoto
authors.forename: Takahisa
authors.initials: T
authors.lastname: Anada
authors.forename: Hideki
authors.initials: H
authors.lastname: Imaizumi
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
authors.forename: Osamu
authors.initials: O
authors.lastname: Suzuki
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D002130:Calcium Phosphates / Q000378:metabolism* / Q000494:pharmacology*; D003460:Crystallization; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006868:Hydrolysis / Q000187:drug effects; D007150:Immunohistochemistry; D020007:Implants, Experimental; D018836:Inflammation Mediators / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D015675:Osteocalcin / Q000378:metabolism; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D053495:Osteopontin / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties / Q000187:drug effects; D000071681:Tartrate-Resistant Acid Phosphatase; D013977:Tibia / Q000002:abnormalities / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D013997:Time Factors
chemical_list: D002130:Calcium Phosphates; D016207:Cytokines; D018836:Inflammation Mediators; D007527:Isoenzymes; D012333:RNA, Messenger; C485817:beta-tricalcium phosphate; D015675:Osteocalcin; D053495:Osteopontin; C022045:octacalcium phosphate; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase