title: Guided tissue fabrication from periosteum using preformed biodegradable polymer scaffolds.
abstract: A successful tissue engineering method for bone replacement would imitate natural bone graft by providing the essential elements for new bone formation using synthetic scaffolds, osteogenic cell populations, and bone induction factors. This is a study of the suitability of various formulations of poly(DL-lactic-co-glycolic acid) (PLGA) foams to provide a tissue conducting scaffold in an ovine model for bone flap fabrication. Three formulations were used of different copolymer ratio and molecular weight. Porous wafers of PLGA were stacked into rectangular chambers (volume 4 cm3) enclosed on five sides. Some chambers also contained autologous morcellized bone graft (MBG). The chambers were inserted with the open face adjacent to the cambium layer of the periosteum in rib beds of seven sheep and harvested after 8 weeks in vivo. Gross and histologic examination of the resulting tissue specimens demonstrated molded units of vascularized tissue generally conforming to the shape of the chambers and firmly attached to the periosteum. Polymer degradation appeared to occur by varying degrees based on polymer formulation. New bone formation was observed only in areas containing MBG. There was no evidence of significant inflammatory reaction or local tissue damage at 8 weeks. We conclude that a PLGA foam scaffold is (1) an efficient conductor of new tissue growth but not osteoinductive, (2) contributes to the shape of molded tissue, and (3) biocompatible when used in this model. Further studies are warranted to develop practical methods to deliver bone induction factors to the system to promote osseous tissue generation throughout the synthetic scaffold.
authors.affiliation: lnstitute of Biosciences and Bioengineering, Rice University, Houston, TX, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Thomson
authors.forename: A G
authors.initials: AG
authors.lastname: Mikos
authors.forename: E
authors.initials: E
authors.lastname: Beahm
authors.forename: J C
authors.initials: JC
authors.lastname: Lemon
authors.forename: W C
authors.initials: WC
authors.lastname: Satterfield
authors.forename: T B
authors.initials: TB
authors.lastname: Aufdemorte
authors.forename: M J
authors.initials: MJ
authors.lastname: Miller
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials; D016025:Bone Transplantation; D015194:Diffusion Chambers, Culture; D048091:Guided Tissue Regeneration; D020007:Implants, Experimental; D019344:Lactic Acid; D010521:Periosteum / Q000254:growth & development*; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D019904:Polymethyl Methacrylate; D012756:Sheep
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D019904:Polymethyl Methacrylate