title: Flexor tendon tissue engineering: acellularized and reseeded tendon constructs.
abstract: BACKGROUND
  Tissue engineering of flexor tendons requires scaffolds with adequate strength and biocompatibility. The biomechanical properties of acellularized and reseeded flexor tendon scaffolds are unknown. Acellularized tendons and reseeded constructs were tested to determine whether the treatment process had altered their biomechanical properties.
  
  
  METHODS
  Rabbit flexor tendons were acellularized using a freeze-thaw cycle followed by trypsin and Triton-X treatment. Complete acellularization of the tendon samples was confirmed by histology and by attempting to obtain viable cells by trypsin treatment of acellularized tendon. Reseeded constructs were obtained by incubating acellularized tendons in a tenocyte suspension. Tensile testing was performed to compare the ultimate tensile stress and elastic modulus of acellularized tendons and reseeded flexor tendon constructs to control flexor tendons.
  
  
  RESULTS
  The treatment protocol successfully acellularized flexor tendons. No cells were seen within the tendon on histologic assessment, and no viable cells could be obtained from acellularized tendon. Acellularized tendon was successfully reseeded with tenocytes, although cell adhesion was limited to the surface of the tendon scaffold. Tensile testing showed that acellularized tendon had the same ultimate stress and elastic modulus as normal tendons. Reseeded tendons had the same elastic modulus as normal tendons, but hind-paw tendon constructs showed a decrease in ultimate stress compared with normal tendons (50.09 MPa versus 66.01 MPa, p = 0.026).
  
  
  CONCLUSIONS
  Acellularized flexor tendons are a potential high-strength scaffold for flexor tendon tissue engineering. This approach of acellularization and reseeding of flexor tendons may provide additional intrasynovial graft material for hand reconstruction.
authors.affiliation: Stanford and Palo Alto, Calif. From the Division of Plastic and Reconstructive Surgery, Stanford University Medical Center; the Bone and Joint Rehabilitation Research and Development Center, Veterans Affairs Palo Alto Health Care System; and the Department of Functional Restoration, Stanford School of Medicine.
authors.forename: Alphonsus K S
authors.initials: AKS
authors.lastname: Chong
authors.forename: Jonathan
authors.initials: J
authors.lastname: Riboh
authors.forename: R Lane
authors.initials: RL
authors.lastname: Smith
authors.forename: Derek P
authors.initials: DP
authors.lastname: Lindsey
authors.forename: Hung M
authors.initials: HM
authors.lastname: Pham
authors.forename: James
authors.initials: J
authors.lastname: Chang
mesh_terms: D000818:Animals; D008297:Male; D023421:Models, Animal; D011817:Rabbits; D013708:Tendon Injuries / Q000601:surgery*; D013710:Tendons / Q000166:cytology* / Q000637:transplantation*; D023822:Tissue Engineering / Q000379:methods*; D020858:Tissue and Organ Harvesting / Q000379:methods; D014184:Transplantation, Homologous