title: Injection of human mesenchymal stem cells improves healing of vocal folds after scar excision--a xenograft analysis.
abstract: OBJECTIVE
  Using a xenograft model the aim was to analyze if injection of human mesenchymal stem cells (hMSC) into the rabbit vocal fold (VF), after excision of an established scar, can improve the functional healing of the VF.
  
  
  METHODS
  Prospective design with an experimental xenograft model.
  
  
  METHODS
  The VFs of 12 New Zealand rabbits were injured by a bilateral localized resection. After 9 weeks the scar after the resection was excised and hMSC were injected into the VFs. After another 10 weeks 10 VFs were dissected and stained for histology. Lamina propria thickness and relative content of collagen type I were measured. Viscoelasticity of 14 VFs at phonatory frequencies was quantified by a simple-shear rheometer. The hMSC survival was determined using a human DNA specific reference probe, that is, FISH analysis.
  
  
  RESULTS
  The viscoelastic measurements, that is, dynamic viscosity and elastic shear modulus for the hMSC-treated VFs, were found to be similar to those of normal controls and were significantly lower than those of untreated controls (P < .05). A significant reduction in lamina propria thickness was also shown for the hMSC treated VFs compared with the untreated VFs (P < .05). This histologic finding corresponded with the viscoelastic results. No hMSC survived 10 weeks after the injection.
  
  
  CONCLUSIONS
  Human mesenchymal stem cells injected into the rabbit VF following the excision of a chronic scar, were found to enhance the functional healing of the VF with reduced lamina propria thickness and restored viscoelastic shear properties.
authors: Department of Otorhinolaryngology, Östersund Hospital, Östersund, Sweden, and Karolinska Institutet, Stockholm, Sweden. bengt.svensson@jll.se
authors: Bengt
authors: B
authors: Svensson
authors: Srinivasa R
authors: SR
authors: Nagubothu
authors: Jessica
authors: J
authors: Cedervall
authors: Roger W
authors: RW
authors: Chan
authors: Katrina
authors: K
authors: Le Blanc
authors: Miwako
authors: M
authors: Kimura
authors: Lars
authors: L
authors: Ährlund-Richter
authors: Anna
authors: A
authors: Tolf
authors: Stellan
authors: S
authors: Hertegård
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D015552:Injections, Intralesional; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D009092:Mucous Membrane / Q000473:pathology*; D011817:Rabbits; D011897:Random Allocation; D012016:Reference Values; D018709:Statistics, Nonparametric; D014183:Transplantation, Heterologous; D014827:Vocal Cords / Q000473:pathology / Q000601:surgery; D014945:Wound Healing / Q000502:physiology*