INVESTIGATION OF THE EXPRESSION OF THE EXTRACELLULAR-MATRIX GLYCOPROTEINS TENASCIN AND FIBRONECTIN DURING ACNE-VULGARIS

Tenascin and fibronectin are extracellular matrix glycoproteins which can interact with cells and alter their capacity to adhere, migrate an d proliferate. In contrast with fibronectin, tenascin has a restricted distribution in normal skin, but is induced during epidermal prolifer ation, and in wound healing. Because acne involves hyperproliferation of ductal keratinocytes, and rupture of the duct may occur during infl ammation, the distribution of tenascin and fibronectin was investigate d in acne lesions, and also in acne keloids. Biopsies obtained from pa tients attending the acne clinics were cryostat-sectioned and stained with tenascin antiserum. The extent of tenascin staining in the dermis around the pilosebaceous unit was measured. Tenascin was continually expressed around normal control pilosebaceous ducts; it was maximal ar ound the acroinfundibulum, extending 20.83 +/- 9.32 mu m (n=14) into t he dermis, compared with staining around the infrainfundibulum (11.88 +/- 3.70 mu m, n=14). This was not significantly different from staini ng around normal pilosebaceous ducts obtained from acne patients. In n on-inflamed lesions tenascin staining increased significantly around t he infrainfundibulum to 76.88 +/- 29.97 mu m (n=12), compared with thi s region in the normal follicles. The staining around the acroinfundib ulum did not change significantly. Around inflamed lesions the whole o f the dermis was positive for tenascin. No changes were detected in th e staining pattern for fibronectin, which stained the whole dermis in all the sections tested. The keloid samples stained strongly for both extracellular matrix glycoproteins. Thus, increased tenascin expressio n appears to be associated with the development of acne lesions. Tenas cin production may be induced by hyperproliferation of ductal keratino cytes, and localized loss of control in this process may contribute to the production of acne keloids.