title: Hydroxyapatite coating affects the Wnt signaling pathway during peri-implant healing in vivo.
abstract: Owing to its bio- and osteoconductivity, hydroxyapatite (HA) is a widely used implant material, but its osteogenic properties are only partly evaluated in vitro and in vivo. The present study focused on bone healing adjacent to HA-coated titanium (Ti) implants, with or without incorporated lithium ions (Li(+)). Special attention was given to the Wnt signaling pathway. The implants were inserted into rat tibia for 7 or 28 days and analyzed ex vivo, mainly by histomorphometry and quantitative real-time polymerase chain reaction (qPCR). HA-coated implants showed, irrespective of Li(+) content, bone-implant contact (BIC) and removal torque values significantly higher than those of reference Ti. Further, the expression of OCN, CTSK, COL1A1, LRP5/6 and WISP1 was significantly higher in implant-adherent cells of HA-coated implants, with or without Li(+). Significantly higher β-catenin expression and significantly lower COL2A1 expression were observed in peri-implant bone cells from HA with 14 ng cm(-2) released Li(+). Interestingly, Ti implants showed a significantly larger bone area (BA) in the threads than HA with 39 ng cm(-2) released Li(+), but had a lower BIC than any HA-coated implant. This study shows that HA, with or without Li(+), is a strong activator of the Wnt signaling pathway, and may to some degree explain its high bone induction capacity.
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden. Electronic address: anna.thorfve@biomaterials.gu.se.
authors.forename: A
authors.initials: A
authors.lastname: Thorfve
authors.affiliation: BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; Department of Engineering Sciences, Angstrom Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Lindahl
authors.affiliation: BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; Department of Engineering Sciences, Angstrom Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: W
authors.initials: W
authors.lastname: Xia
authors.affiliation: BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; Department of Oral and Maxillofacial Surgery, Southern Tohoku Research Institute for Neuroscience, Southern Tohoku General Hospital, 71-15 Yatsuyamada Koriyama, Fukushima 9638-563, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Igawa
authors.affiliation: BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; Department of Clinical Chemistry and Transfusion Medicine, The Sahlgrenska Academy, University of Gothenburg, Bruna Straket 16, SE-413 45 Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Lindahl
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Thomsen
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Palmquist
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, The Sahlgrenska Academy at University of Gothenburg, Box 412, SE-405 30 Gothenburg, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Tengvall
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000187:drug effects / Q000648:ultrastructure; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D017886:Durapatite / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000187:drug effects; D007150:Immunohistochemistry; D020007:Implants, Experimental; D008297:Male; D017207:Rats, Sprague-Dawley; D019415:Torque; D060449:Wnt Signaling Pathway / Q000187:drug effects* / Q000235:genetics; D014945:Wound Healing / Q000187:drug effects*; D051176:beta Catenin / Q000378:metabolism
chemical_list: D020099:Coated Materials, Biocompatible; D051176:beta Catenin; D017886:Durapatite
keywords: Gene expression; Hydroxyapatite; Lithium; Osseointegration; Wnt signaling pathway