title: Inability of transforming growth factor-beta 1, combined with a bioabsorbable polymer paste, to promote healing of bone defects in the rat distal femur.
abstract: The ability of transforming growth factor-beta 1 (TGF-beta 1) to promote bone formation suggests that it may have potential as a therapeutic agent in bone defects. However, there still exists a need for an effective method of delivering TGF-beta 1 to the site of an osseous defect. In the present study, TGF-beta 1 was embedded in a bioabsorbable polymer paste (a blend of an L-lactide oligomer and a copolymer of epsilon-caprolactone and DL-lactide). The release of TGF-beta 1 from the polymer paste was examined in vitro with an enzyme-linked immunosorbent assay, which showed sustained release of active TGF-beta 1 over a 7-day period. Further, the polymer paste was used to fill a bone defect in the rat distal femur. The amount of TGF-beta 1 per rat was 50 micrograms, while in a control group we used an identical polymer paste without the growth factor. After a follow-up of 1 week and 3 weeks, the femurs were examined radiographically, histologically, histomorphometrically, microradiographically, and were also used for tetracycline-labeling studies. TGF-beta 1 did not enhance healing of the bone defect. A combination of growth factors would probably be a more potent osteoinductor than TGF-beta 1 alone.
authors.affiliation: Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, Topeliuksenkatu 5, 00260 Helsinki, Finland. Laura.Tielinen@hus.fi
authors.forename: L
authors.initials: L
authors.lastname: Tielinen
authors.forename: M
authors.initials: M
authors.lastname: Manninen
authors.forename: P
authors.initials: P
authors.lastname: Puolakkainen
authors.forename: M
authors.initials: M
authors.lastname: Kellomäki
authors.forename: P
authors.initials: P
authors.lastname: Törmälä
authors.forename: J
authors.initials: J
authors.lastname: Rich
authors.forename: J
authors.initials: J
authors.lastname: Seppälä
authors.forename: P
authors.initials: P
authors.lastname: Rokkanen
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D016723:Bone Remodeling / Q000187:drug effects*; D004343:Drug Implants; D017102:Fracture Healing / Q000187:drug effects*; D008297:Male; D014677:Pharmaceutical Vehicles; D011091:Polyesters; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
chemical_list: D004343:Drug Implants; D014677:Pharmaceutical Vehicles; D011091:Polyesters; D011994:Recombinant Proteins; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C062968:lactide-caprolactone copolymer