In Reference to Growth factors expression in hyaluronic acid fat graft myringoplasty.

OBJECTIVES/HYPOTHESIS To investigate the effect of hyaluronic acid (HA) associated to fat graft on growth factors expression during the healing process of tympanic membrane (TM) perforations in guinea pigs using the hyaluronic acid fat graft myringoplasty (HAFGM) technique. STUDY DESIGN Prospective randomized animal study. METHODS Thirty guinea pigs were divided equally into three groups: group I (control group), group II (fat graft myringoplasty technique), and group III (HAFGM technique). TMs were perforated on day 1 and then sampled on days 0, 3, 8, and 21 and tested for the expression of: epidermal growth factor (EGF), insulin-like growth factor (IGF), tumor necrosis factor α (TNF α), vascular endothelial growth factor (VEGF), and keratinocyte growth factor (KGF). Five perforated TMs were taken at day 0 from group I to serve as a reference level. RESULTS Group III showed an increased expression of all tested growth factors, except for KGF. EGF was highest in the early healing process; then IGF peaked at day 8 with statistically significant increase compared to groups I and II. TNF α in group III was significantly higher than group I throughout the study, with a peak level at day 21. VEGF was significantly higher in group III compared to group I at days 3 and 21. Neovascularization and scarless TM closure was obtained in group III, while spontaneous closure was associated with thin-layered and scarred TM in group I. CONCLUSIONS HA association to fat graft in perforated TM increases the expression of the endogenous growth factors, suggesting that such an association is advantageous for healing. LEVEL OF EVIDENCE N/A.