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Growth Factors in Subglottic Stenosis

We sought to define the role of fibrogenic peptides in subglottic stenosis (SGS). Biopsy specimens were obtained from patients with stenosis following endotracheal intubation (group 1, n = 5, mean age 5), patients without a history of any precedent trauma, ie, idiopathic stenosis (group 2, n = 3, mean age 40), and those without stenosis (group 3, n = 3, mean age 70). Formalin-fixed biopsy specimens were analyzed following immunohistochemical staining to determine if epidermal growth factor (EGF), platelet-derived growth factor-AA and -BB (PDGF-AA/BB), transforming growth factor-β1 and -β2 (TGF-β,β2), or basic fibroblast growth factor (bFGF) was deposited in these tissues. Blinded analysis revealed TGF-β2 and PDGF-AA to be present in seven of eight biopsy specimens from SGS and absent in controls. Staining for PDGF-BB was observed in the mucosa and submucosa and occasionally within vessel walls. Staining of individual growth factors appeared to correlate closely with the presence of granulation tissue. Essentially no bFGF or TGF-β1 was observed. Differences were found between patients in groups 1 and 2; tissue from group 1 revealed deposition of EGF and PDGF-BB in submucosa, epithelium, and vasculature. In summary, our experimental findings implicate PDGF and TGF-β2, perhaps acting in concert, in mediating the pathologic fibrotic process observed in subglottic stenosis. Epidermal growth factor, in conjunction with TGF-β and PDGF, may also have a role, but further investigation is needed to more precisely define it.