title: Sinonasal epithelial wound resealing in an in vitro model: inhibition of wound closure with IL-4 exposure.
abstract: BACKGROUND
  Prolonged healing and persistent inflammation following surgery for rhinosinusitis impacts patient satisfaction and healthcare resources. Cytokines interleukin (IL)-4, IL-5, and IL-13 are important mediators in T-helper 2 (Th2) inflammatory rhinosinusitis. Decreased wound healing has been demonstrated with Th2 cytokine exposure, but this has not been extensively studied in sinonasal epithelium. We hypothesized that in vitro exposure of primary sinonasal epithelial cell cultures to Th2 inflammatory cytokine IL-4 and IL-13 would impair wound resealing and decrease expression of annexin A2 at the wound edge.
  
  
  METHODS
  Following 24-hour exposure to IL-4, IL-5, or IL-13 vs controls, sterile linear mechanical wounds were created in primary sinonasal epithelial cultures (n = 12 wounds per condition). Wounds were followed for 36 hours or until complete closure, and residual wound areas were calculated by image analysis. Group differences in annexin A2 were assessed by immunofluorescence labeling, confocal microscopy, and Western blots.
  
  
  RESULTS
  Significant wound closure differences were identified across cytokine exposure groups (p < 0.001). Mean percentage wound closure at the completion of the 36-hour time course was 98.41% ± 3.43% for control wounds vs 85.02% ± 18.46% for IL-4 exposed wounds. IL-13 did not significantly impair sinonasal epithelial wound resealing in vitro. Annexin A2 protein levels were decreased in IL-4 treated wounds when compared to control wounds (p < 0.01).
  
  
  CONCLUSIONS
  Th2 cytokine IL-4 decreases sinonasal epithelial wound closure in vitro. Annexin A2 is also diminished with IL-4 exposure. This supports the hypothesis that IL-4 exposure impairs sinonasal epithelial wound healing and may contribute to prolonged healing in Th2 inflammatory rhinosinusitis.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Emory University, Atlanta, GA 30308, USA. skmille@emory.edu
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Wise
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Den Beste
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Hoddeson
authors.forename: Charles A
authors.initials: CA
authors.lastname: Parkos
authors.forename: Asma
authors.initials: A
authors.lastname: Nusrat
mesh_terms: D017306:Annexin A2 / Q000378:metabolism*; D015153:Blotting, Western; D016022:Case-Control Studies; D016207:Cytokines / Q000494:pharmacology*; D004847:Epithelial Cells / Q000378:metabolism*; D004848:Epithelium / Q000293:injuries / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D018793:Interleukin-13 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D015848:Interleukin-5 / Q000494:pharmacology; D018613:Microscopy, Confocal; D009296:Nasal Cavity / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014945:Wound Healing / Q000502:physiology*
chemical_list: D017306:Annexin A2; D016207:Cytokines; D018793:Interleukin-13; D015848:Interleukin-5; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4