title: Negating Tissue Contracture Improves Volume Maintenance and Longevity of In Vivo Engineered Tissues.
abstract: BACKGROUND
  Engineering large, complex tissues in vivo requires robust vascularization to optimize survival, growth, and function. Previously, the authors used a "chamber" model that promotes intense angiogenesis in vivo as a platform for functional three-dimensional muscle and renal engineering. A silicone membrane used to define the structure and to contain the constructs is successful in the short term. However, over time, generated tissues contract and decrease in size in a manner similar to capsular contracture seen around many commonly used surgical implants. The authors hypothesized that modification of the chamber structure or internal surface would promote tissue adherence and maintain construct volume.
  
  
  METHODS
  Three chamber configurations were tested against volume maintenance. Previously studied, smooth silicone surfaces were compared to chambers modified for improved tissue adherence, with multiple transmembrane perforations or lined with a commercially available textured surface. Tissues were allowed to mature long term in a rat model, before analysis.
  
  
  RESULTS
  On explantation, average tissue masses were 49, 102, and 122 mg; average volumes were 74, 158 and 176 μl; and average cross-sectional areas were 1.6, 6.7, and 8.7 mm for the smooth, perforated, and textured groups, respectively. Both perforated and textured designs demonstrated significantly greater measures than the smooth-surfaced constructs in all respects.
  
  
  CONCLUSIONS
  By modifying the design of chambers supporting vascularized, three-dimensional, in vivo tissue engineering constructs, generated tissue mass, volume, and area can be maintained over a long time course. Successful progress in the scale-up of construct size should follow, leading to improved potential for development of increasingly complex engineered tissues.
authors.affiliation: Ann Arbor, Mich. From the Section of Plastic Surgery, Center for Plastic and Reconstructive Surgery, the Department of Oral and Maxillofacial Surgery, School of Dentistry, the Division of Nephrology, Department of Internal Medicine, and the Section of Plastic and Reconstructive Surgery, University of Michigan; and Innovative Biotherapies, Inc.
authors.forename: Ian F
authors.initials: IF
authors.lastname: Lytle
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Kozlow
authors.forename: Wen X
authors.initials: WX
authors.lastname: Zhang
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Buffington
authors.forename: H David
authors.initials: HD
authors.lastname: Humes
authors.forename: David L
authors.initials: DL
authors.lastname: Brown
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D003286:Contracture / Q000209:etiology / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344; D012828:Silicones; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D012828:Silicones