Alpha11 integrin in the human cornea: importance in development and disease.

PURPOSE: To examine the distribution of the alpha11 integrin chain in the human cornea during fetal development and in normal and diseased adult human corneas. METHODS: Six fetal corneas, 10 to 20 weeks of gestation (wg), and 18 adult corneas including 3 normal, 7 with keratoconus, 5 with pseudophakic bullous keratopathy (PBK), 2 with Fuchs' corneal dystrophy, and 1 with a scar after deep lamellar keratoplasty (DLKP) were processed for immunohistochemistry with specific antibodies against the alpha11 integrin chain; collagen I, IV, and V; and alpha-smooth muscle actin (alpha-SMA). The cellular source of alpha11 integrin chain was further investigated in cell cultures. RESULTS: At 10 to 17 wg, the alpha11 integrin chain was predominantly present in the anterior corneal stroma. At 20 wg, in normal adult corneas and in Fuchs' dystrophy corneas there was weak staining in the stroma. The PBK corneas showed variable and weak staining, generally accentuated in the posterior stroma near Descemet's membrane. In contrast, the anterior portion of the stroma in the keratoconus corneas was strongly stained in an irregular streaky pattern. Human corneal fibroblasts/myofibroblasts produced alpha11 integrin chain in culture. Cultures treated with TGF-beta showed higher content of both alpha-SMA and the alpha11 integrin chain. CONCLUSIONS: The presence of the alpha11 integrin chain during early corneal development and the enhanced expression in scarred keratoconus corneas indicates that this integrin chain is likely to play an important role in collagen deposition during corneal development and in keratoconus with a scarring component and compromised basement membrane integrity.