Combined chondrocyte–copolymer implantation with slow release of basic fibroblast growth factor for tissue engineering an auricular cartilage construct

Abstract

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.

Vascular regeneration by pinpoint delivery of growth factors using a microcatheter reservoir system in a rabbit hind-limb ischemia model

“…Several previous studies have reported on how bFGF bonds to GMS and is slowly released from GMS (19)(20)(21)(22). We obtained bFGF impregnated-GMS through the same method described in these previous studies.…”

Biodegradable elastomeric scaffolds with basic fibroblast growth factor release

“…Natural materials include gelatin [31,32], collagen [33], fibrin [34], heparin [35] and alginate. [36] Synthetic matrices have been generated from poly(ethylene glycol)-g-poly(lactic acid) [37], poly(lactic acid) [38], poly(lactic-co-glycolic acid) [39,40], and methylidene malonate polymers. [41] From a mechanical perspective, these scaffolds have ranged from relatively weak materials (e.g.…”

Optimal Amount of Basic Fibroblast Growth Factor in Gelatin Sponges Incorporating β-Tricalcium Phosphate with Chondrocytes

“…Isogai et al developed a composite scaffold to fabricate a complicated 3D engineered auricular cartilage with a slow-release b-FGF system. 29,41,42 From *50 to 80 mg/cm 3 b-FGF had been impregnated onto gelatin sponges. The enhanced vascular networks 41 induced by slow-release b-FGF and the proliferated chondrocytes are involved in enhanced chondrogenesis and production of extracellular matrix in cartilage regeneration.…”

“…b-FGF-impregnated gelatin microspheres with slow release enhanced chondrogenesis in in situ engineered cartilage. 29,30 The relationship between the amount of regenerative cartilage that forms and the amount of b-FGF impregnated in gelatin microspheres has not been clarified. This study investigated the optimal amount of b-FGF with gelatin sponges to fabricate engineered cartilage.…”

“…Isogai et al 29 first reported that a slow-release b-FGF system augments chondrogenesis in tissue-engineered cartilage constructs by using b-FGF-impregnated gelatin sponges in vivo. b-FGF-impregnated gelatin microspheres with slow release enhanced chondrogenesis in in situ engineered cartilage.…”