transforming-growth-factor-beta and Ear-Diseases

The external auditory canal cholesteatoma (EACC) is a rare disease with hyperproliferation and destructive growth in the adjacent structures. Down-regulation of beta-catenin (key component of the zonula adherens) is a pivotal factor for loose tissue integrity and invasiveness. Transforming growth factor beta1 (TGF-beta1) was reported to decrease beta-catenin in mammary epithelium. We investigated the abrogation of TGF-beta1 and beta-catenin expression in EACC culture cells. Cultured EACC-specimens were incubated with 6 micromol TGF-beta1 antisense. After 48 h, expression of beta-catenin was determined by means of immunohistochemistry. The cells showed an increased mural reactivity to beta-catenin, and intracellular reactivity was unchanged. The untreated cells showed a loss of beta-catenin expression at the membranes. The predominant membranous location after treatment with TGF-beta1 antisense suggests increased tendency of the cells for tissue formation and strong cell-cell adhesion rather than migratory and invasive character, and thus TGF-beta1 antisense application is a useful therapeutical strategy.

Topics: beta Catenin; Cells, Cultured; Cholesteatoma; Cytoskeletal Proteins; Ear Canal; Ear Diseases; Humans; Oligonucleotides, Antisense; Trans-Activators; Transforming Growth Factor beta; Transforming Growth Factor beta1; Up-Regulation

The effects of recombinant human transforming growth factor beta 1 (rhTGF-beta 1) on wound healing were examined in a rabbit ear ulcer model in which rhTGF-beta 1 was applied to full-thickness biopsy ulcers on the ears. The influence of perichondrium on healing was studied by comparing ulcers with and without perichondrium on 1) formation of total healing wound area (HWA, the newly formed connective and granulation tissues within the ulcer) over time and 2) the amount of collagen synthesized by the wound tissue at day 5. The HWA of ulcers with intact perichondrium increased sharply with time and reached a plateau at day 7, whereas a slower healing occurred in the perichondrium-free model where maximal HWA appeared at day 14. Topical application of 100 ng of rhTGF-beta 1 per wound accelerated healing by increasing HWA in both models. The enhancement of healing by rhTGF-beta 1 was associated with increased collagen synthesis. The percent collagen synthesis in the rhTGF-beta 1 was doubled in the perichondrium-intact ulcers and increased 40% in the perichondrium-free ulcers. DNA synthesis in the perichondrium-intact ulcers was not altered by rhTGF-beta 1 when measured at day 5 by in vitro labeling with [3H]thymidine ([3H]TdR). Autoradiography indicated that the primary cells labeled in the wound tissue were epithelial cells and rhTGF-beta 1 enhanced the migration of these cells from the wound margin towards the center. To evaluate the effects of rhTGF-beta 1 on fibroblasts derived from the granulation tissue of the wound, cells were treated with increasing concentrations of rhTGF-beta 1 and DNA and collagen synthesis were determined. rhTGF-beta 1 elicited a biphasic change in percent collagen synthesis with a maximal increase of 50% at 20 pM followed by a decline. A twofold increase in [3H]TdR incorporation that plateaued at 1 nM was also observed. Our results indicate that the cellular responses to rhTGF-beta 1 differ in vivo and in vitro. The perichondrium-intact ulcers contain more wound tissue and have larger responses to rhTGF-beta 1 stimulation, which allows better examination of biochemical and cellular events. The in vivo mechanisms are multi-factorial, which may involve cell migration and recruitment as results of numerous cell/cell and cell/matrix interactions.

Topics: Animals; DNA; Ear Diseases; Fibroblasts; Models, Biological; Protein Biosynthesis; Rabbits; Recombinant Proteins; Skin Ulcer; Stimulation, Chemical; Transforming Growth Factor beta; Wound Healing