Bone formation in transforming growth factor beta-I-loaded titanium fiber mesh implants.
The osteoconductive properties of porous titanium (Ti) fiber mesh with or without a calcium phosphate (Ca-P) coating and osteoinductive properties of noncoated Ti fiber mesh loaded with recombinant human Transforming Growth Factor beta-1 (rhTGF-beta1) were investigated in a rabbit non-critical size cranial defect model. Nine Ca-P-coated and 18 non-coated porous titanium implants, half of them loaded with rhTGF-beta1, were bilaterally placed in the cranium of 18 New Zealand White rabbits. At 8 weeks postoperative, the rabbits were sacrificed and the skulls with the implants were retrieved. Histological analysis demonstrated that in the TGF-beta1-loaded implants, bone had been formed throughout the implant, up to its center, whereas in the non-loaded implants only partial ingrowth of bone was observed. Bone formation had a trabecular appearance together with bone marrow-like tissue. No difference in ingrowth could be observed between the non-TGF-beta1-loaded non-coated implants and the Ca-P-coated ones. All histological findings were confirmed by image analysis: 97% ingrowth was seen in the rhTGF-beta1-loaded implants, while only 57% and 54% ingrowth was observed in the non-loaded Ca-P-coated and non-coated implants, respectively. Bone surface area and bone fill were significantly higher in the rhTGF-beta1-loaded implants (1.37 mm2 and 36%, respectively) than in the non-loaded implants (0.57 mm2 and 26%). No statistical difference was found for any parameter between the Ca-P-coated and noncoated implants. Quadruple fluorochrome labeling showed that in the Ti and Ti-CaP implants mainly bone guidance had occurred from the former defect edge, while in the Ti-TGF-beta1 implants bone formation had mainly started in the center of a pore and proceeded in a centrifugal manner. Our results show that: (1) the combination of Timesh with TGF-beta1 can induce orthotopic bone formation; (2) Ti-fiber mesh has good osteoconductive properties; (3) a thin Ca-P coating, as applied in this study, does not seem to further enhance the bone-conducting properties of a titanium scaffold material.
Vehof
Johan W M
JW
Department of Biomaterials, College of Dental Science, University Medical Center Nijmegen, The Netherlands.
Haus
Marcus T U
MT
de Ruijter
Anja E
AE
Spauwen
Paul H M
PH
Jansen
John A
JA
D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D005456:Fluorescent Dyes; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D016555:Matched-Pair Analysis; D008856:Microscopy, Fluorescence; D010012:Osteogenesis / Q000187:drug effects* / Q000502:physiology; D016062:Porosity; D019736:Prostheses and Implants; D011817:Rabbits; D011994:Recombinant Proteins; D012886:Skull / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D013223:Statistics as Topic; D013526:Surgical Mesh; D014025:Titanium / Q000737:chemistry; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000627:therapeutic use*; D053773:Transforming Growth Factor beta1; D014945:Wound Healing
D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D005456:Fluorescent Dyes; D011994:Recombinant Proteins; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D014025:Titanium; C485829:calcium phosphate, dibasic, anhydrous