Growth factors in tympanic membrane perforations

Objective: Little is known about the arrested healing of chronic central ty mpanic membrane perforations and the mechanism involved in this process. So me authors have traced the failure to a growth factor deficiency at the per foration margin. In addition, recently, several growth factors have been tr ied out to improve tympanic membrane (TM) closure in animals. The authors s ought to determine the expression of some well-known growth factor peptides in normal human TM and in TMs with a chronic central perforation. Materials and Methods: Total TM specimens were obtained from patients with a normal TM (N = 10) soon after death and from patients with a chronic perf oration (N = 20) undergoing myringoplasty with use of an allograft TM. Form aldehyde solution-fixed TMs were analyzed after immunohistochemical stainin g using highly purified monoclonal antibodies to determine whether epiderma l growth factor receptor (EGF-r), transforming growth factor-alpha (TGF-alp ha), basic fibroblast growth factor (b-FGF), or transforming growth factor- beta 1 (TGF-beta 1) was expressed in the TMs. Results: The distribution pattern for EGF-r, TGF-alpha, and b-FGF was simil ar in perforated and nonperforated TMs. In contrast to this, TGF-beta 1 sta ining was markedly different in perforated and nonperforated TMs. No or min imal TGF-beta 1 was observed in normal TMs, whereas TGF-beta 1 staining was prominent in perforated membranes, mostly at the perforation border. Conclusions: The authors experimental findings imply that EGF-r, b-FGF, and TGF-alpha expression are not significantly different in TMs with and witho ut a central chronic perforation. However, for TGF-beta 1, the authors foun d an increased staining pattern in perforated TMs when compared with that o f normal TMs, and staining at the fibrotic and scarred perforation margin w as pronounced. Based on these findings, the authors speculate on the possib le role of TGF-beta 1 in the development of the fibrotic scar at the perfor ation margin explaining the deficient healing pattern of tympanic membranes in chronic otitis media. Possible clinical implications for the future, in cluding growth factor therapy, are discussed.