title: High-level expression of matrix-associated transforming growth factor-beta1 in benign airway stenosis.
abstract: OBJECTIVE
  Acquired tracheal and subglottic stenosis frequently leads to severe airway narrowing, which requires repeated interventions, such as dilatation, laser resection, stent implantation, or surgery. To get a more detailed insight into the pathogenesis of this condition, we investigated the expression of profibrotic cytokines and the proliferation of the airway wall in benign human airway stenoses.
  
  
  METHODS
  Specimens from patients with subglottic and tracheal stenosis and stent-related stenoses were obtained (n = 20) for reverse transcription (RT) polymerase chain reaction (PCR) analysis and immunohistochemistry testing.
  
  
  RESULTS
  Transforming growth factor (TGF)-beta1 messenger RNA expression was significantly increased in biopsy specimens from stent-related stenoses compared to nonstenotic control sections. In contrast, TGF-beta3 and interleukin-1beta showed no such differences in messenger RNA expression. Immunohistochemistry revealed a strong matrix-associated, subepithelial expression of TGF-beta1 in tracheal stenosis. Proliferating Ki-67-positive cells were mainly localized in the basal epithelial layer. Only 2 of 16 patients with tracheal stenoses and 3 of 4 patients with stent-related stenoses showed a weak expression of Ki-67-positive cells in the subepithelium. Furthermore, TGF-beta1 dose-dependently enhanced the proliferation of human lung fibroblasts in vitro, even in the presence of mitomycin-C.
  
  
  CONCLUSIONS
  While a weak subepithelial proliferation occurs in stent-related stenoses, the dominant factor in late stages of untreated tracheal stenoses seems to be the high-level expression of TGF-beta1 and the deposition of extracellular matrix.
authors: Lungenklinik Hemer, Center for Pulmonary Medicine and Thoracic Surgery, Theo-Funccius Str 1, 58675 Hemer, Germany.
authors: Christian
authors: C
authors: Karagiannidis
authors: Viorica
authors: V
authors: Velehorschi
authors: Barbara
authors: B
authors: Obertrifter
authors: Hans-Nicol
authors: HN
authors: Macha
authors: Albert
authors: A
authors: Linder
authors: Lutz
authors: L
authors: Freitag