Combined chondrocyte-copolymer implantation with slow release of basic fibroblast growth factor for tissue engineering an auricular cartilage construct.
Basic fibroblast growth factor (b-FGF) may have a role in tissue-engineered chondrogenesis. However, when applied in solution, b-FGF rapidly diffuses from the implant site. In another approach for tissue engineering, poly-lactide-based copolymers have shown promise as scaffolds for chondrocytes used to tissue engineer auricular cartilage in the shape of an ear. This study evaluated the effectiveness of b-FGF impregnated in gelatin microspheres to achieve slow growth factor release for augmenting the in vivo chondrogenic response. Whereas 125I-labeled b-FGF injected in solution showed rapid in vivo clearance from the injection site (only 3% residual after 24 h), when incorporated into gelatin microspheres, 44% and 18% of the b-FGF remained at 3 and 14 days, respectively. Canine chondrocytes were isolated and grown in vitro onto ear-shaped poly-lactide/caprolactone copolymers for 1 week, then implanted into the dorsal subcutaneous tissue of nude mice; implants contained b-FGF either in free solution or in gelatin microspheres. A third group underwent preinjection of b-FGF in gelatin microspheres 4 days before chondrocyte-copolymer implantation. The implants with b-FGF-incorporated microspheres showed the greatest chondrogenic characteristics at 5 and 10 weeks postoperatively: good shape and biomechanical trait retention, strong (histologic) metachromasia, rich vascularization of surrounding tissues, and increased gene expression for type II collagen (cartilage marker) and factor VIII-related antigen (vascular marker). In the case of implant site preadministration with b-FGF-impregnated microspheres, the implant architecture was not maintained as well, and reduced vascularization and metachromasia was also apparent. In conclusion, these findings indicate that a sustained release of b-FGF augments neovascularization and chondrogenesis in a tissue-engineered cartilage construct.
Department of Plastic and Reconstructive Surgery, Kinki University School of Medicine, 377-2 Ono-higashi, Osaka-Sayama, Osaka, Japan 589-8511. isogai@med.kindai.ac.jp
Noritaka
N
Isogai
Tadaaki
T
Morotomi
Sumio
S
Hayakawa
Hiroshi
H
Munakata
Yasuhiko
Y
Tabata
Yoshito
Y
Ikada
Hiroshi
H
Kamiishi
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002356:Cartilage / Q000166:cytology / Q000378:metabolism; D019902:Chondrocytes / Q000378:metabolism / Q000637:transplantation*; D003692:Delayed-Action Preparations; D004285:Dogs; D004431:Ear, External; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage / Q000378:metabolism*; D005780:Gelatin; D020869:Gene Expression Profiling; D006801:Humans; D020007:Implants, Experimental; D051379:Mice; D008863:Microspheres; D011091:Polyesters; D023822:Tissue Engineering / Q000379:methods
D003692:Delayed-Action Preparations; D011091:Polyesters; D016222:Fibroblast Growth Factor 2; C062968:lactide-caprolactone copolymer; D005780:Gelatin