CONFOCAL IMAGING OF THE ALPHA-6 AND BETA-4 INTEGRIN SUBUNITS IN THE HUMAN CORNEA WITH AGING

Purpose. The purpose of this study was to examine changes in the distribution Methods. Thirty normal corneas were examined and divided into three groups; corneas from children younger than 2 years, corneas from adults 29 to 70 years, and corneas from adults older than 70 years. The corneas were frozen and the sections were cut, double-stained with monoclonal antibodies to the integrin subunits, and visualized with Texas Red or fluorescein using confocal laser scanning microscopy. Computer imaging was conducted to determine differences. Results. The alpha6, subunit was generally localized along the basal and lateral surfaces of basal epithelial cells and projected into Bowman's membrane. The beta4 subunit was only present along the basal surface. Overall, the major age-related difference was the loss of continuous a, and beta4 subunits along the basal surface of basal epithelial cells. When reconstructed images from corneas of individuals older than 70 years were optically sectioned en face, the alpha6 subunit appeared discontinuous. If the same optical images were viewed from corneas of younger individuals, the staining was continuous. The number and distribution of hemidesmosomes along the basal lamina did not change with age in the corneas examined. Conclusions. Using computer imaging associated with confocal laser scanning microscopy, we have demonstrated that there is an age-related change in the localization of the alpha6 and beta4 subunits.