title: Precultivation of engineered human nasal cartilage enhances the mechanical properties relevant for use in facial reconstructive surgery.
abstract: OBJECTIVE
  To investigate if precultivation of human engineered nasal cartilage grafts of clinically relevant size would increase the suture retention strength at implantation and the tensile and bending stiffness 2 weeks after implantation. SUMMARY BACKGROUND INFORMATION: To be used for reconstruction of nasal cartilage defects, engineered grafts need to be reliably sutured at implantation and resist to bending/tension forces about 2 weeks after surgery, when fixation is typically removed.
  
  
  METHODS
  Nasal septum chondrocytes from 4 donors were expanded for 2 passages and statically loaded on 15 x 5 x 2-mm size nonwoven meshes of esterified hyaluronan (Hyaff-11). Constructs were implanted for 2 weeks in nude mice between muscle fascia and subcutaneous tissue either directly after cell seeding or after 2 or 4 weeks of preculture in chondrogenic medium. Engineered tissues and native nasal cartilage were assessed histologically, biochemically, and biomechanically.
  
  
  RESULTS
  Engineered constructs reproducibly developed with culture time into cartilaginous tissues with increasing content of glycosaminoglycans and collagen type II. Suture retention strength was significantly higher (3.6 +/- 2.2-fold) in 2-week precultured constructs than in freshly seeded meshes. Following in vivo implantation, tissues further developed and maintained the original scaffold size and shape. The bending stiffness was significantly higher (1.8 +/- 0.8-fold) if constructs were precultured for 2 weeks than if they were directly implanted, whereas tensile stiffness was close to native cartilage in all groups.
  
  
  CONCLUSIONS
  In our experimental setup, preculture for 2 weeks was necessary to engineer nasal cartilage grafts with enhanced mechanical properties relevant for clinical use in facial reconstructive surgery.
authors.affiliation: Department of Surgery and of Research, University Hospital Basel, Switzerland. jfarhadi@uhbs.ch
authors.forename: Jian
authors.initials: J
authors.lastname: Farhadi
authors.forename: Ilario
authors.initials: I
authors.lastname: Fulco
authors.forename: Sylvie
authors.initials: S
authors.lastname: Miot
authors.forename: Dieter
authors.initials: D
authors.lastname: Wirz
authors.forename: Martin
authors.initials: M
authors.lastname: Haug
authors.forename: Sally C
authors.initials: SC
authors.lastname: Dickinson
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Hollander
authors.forename: A U
authors.initials: AU
authors.lastname: Daniels
authors.forename: Gerhard
authors.initials: G
authors.lastname: Pierer
authors.forename: Michael
authors.initials: M
authors.lastname: Heberer
authors.forename: Ivan
authors.initials: I
authors.lastname: Martin
mesh_terms: D000328:Adult; D000818:Animals; D019902:Chondrocytes / Q000502:physiology*; D006801:Humans; D006820:Hyaluronic Acid / Q000031:analogs & derivatives; D051379:Mice; D008875:Middle Aged; D009300:Nasal Septum / Q000166:cytology*; D018583:Pliability; D012225:Rhinoplasty; D013536:Suture Techniques; D013718:Tensile Strength; D046509:Tissue Culture Techniques / Q000379:methods*; D023822:Tissue Engineering
chemical_list: C086358:hyaluronic acid benzyl ester; D006820:Hyaluronic Acid