title: Microencapsulated cells genetically modified to overexpress human transforming growth factor-beta1: viability and functionality in allogeneic and xenogeneic implant models.
abstract: This study explores the suitability of using encapsulated genetically modified fibroblasts for orthopedic tissue engineering by examining cell survival and persistence of human transforming growth factor-beta (hTGF-beta) overexpression in xenogeneic and allogeneic implant models. Human wild-type fibroblasts, modified to produce a latent form of hTGF-beta, and murine mutant-type fibroblasts, engineered to release a constitutively active form of hTGF-beta, were encapsulated separately in Ca2+ -alginate microcapsules. Following a percentage viability assessment by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) test, microcapsules were implanted into either the subcutaneous or intraperitoneal cavities of mice. Explanted encapsulated cells were characterized for percentage viability and subjected to a release study and a viability test 1 week and 3 weeks following implantation, a time frame consistent with the requirement for orthopedic tissue engineering application of this growth factor. On average, percentage viabilities of encapsulated cells were 64%at implantation, 52% at explantation, and 56%after 1 week following either 1- or 3-week explantation. hTGF-beta release declined following in vivo implantation, more so for xenogeneic than allogeneic models, but remained in the clinically attractive range of 2 to 30 ng/(10(6) implanted cells 24 h). This technical platform for hTGF-beta is very encouraging for cartilage regeneration using orthopedic tissue engineering, and further evaluation is warranted.
authors.affiliation: Center for Biomedical Engineering, Brown University, Providence, Rhode Island, USA. jpaek@tissuegenesis.com
authors.forename: Hyun J
authors.initials: HJ
authors.lastname: Paek
authors.forename: Anelisa B
authors.initials: AB
authors.lastname: Campaner
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Kim
authors.forename: Louis
authors.initials: L
authors.lastname: Golden
authors.forename: Roy K
authors.initials: RK
authors.lastname: Aaron
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Ciombor
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Morgan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lysaght
mesh_terms: D000464:Alginates; D000818:Animals; D001705:Bioprosthesis; D002214:Capsules; D002470:Cell Survival; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000637:transplantation; D015870:Gene Expression; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics; D053773:Transforming Growth Factor beta1; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous
chemical_list: D000464:Alginates; D002214:Capsules; D006603:Hexuronic Acids; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D020723:Glucuronic Acid