Effects of calcium ion-implantation of titanium on bone cell function in vitro.
The modification of titanium (Ti) surfaces by ion-implantation has previously been reported to enhance osseointegration in vivo. However, the mechanisms underlying the apparently improved biocompatibility of these novel implant materials are unknown. The aim of this study is, therefore, to determine the precise effects of calcium ion-implanted Ti on the functional activity of bone cells in vitro. Flow cytometry (FCM) and the reverse transcriptase polymerase chain reaction (RT-PCR) were used to measure the response of bone-derived cells to key bone-associated components, including alkaline phosphatase (ALP), bone morphogenetic protein receptor-1B (BMPR-1B), bone sialoprotein (BSP), osteonectin (ON), and osteopontin (OPN). FCM analysis showed that BMPR-1B, BSP and particularly OPN were significantly up-regulated in MG-63 cells cultured on Ca-implanted Ti compared with control nonimplanted Ti. Moreover, the effects of this novel Ca-Ti surface were found to be mediated, at least partly, via gene activation, since RT-PCR demonstrated the presence of notably elevated levels of OPN mRNA transcripts in the MG-63 cells. These findings thus show that Ti surfaces implanted with Ca ions can enhance the expression of certain bone-associated components in vitro, and suggest that this effect could be the cause of the potential benefit of this material on bone in vivo.
Nayab
Saima N
SN
Division of Biomaterials and Tissue Engineering, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, United Kingdom.
Jones
Frances H
FH
Olsen
Irwin
I
D000293:Adolescent; D000951:Antigens, Neoplasm / Q000378:metabolism; D001842:Bone and Bones / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000737:chemistry* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008422:Materials Testing / Q000379:methods*; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D019736:Prostheses and Implants; D014025:Titanium / Q000378:metabolism*; D015533:Transcriptional Activation
D000951:Antigens, Neoplasm; D053495:Osteopontin; D014025:Titanium; D002118:Calcium