Abstract
Purpose :
Collagen 1A1 (COL 1A1), fibronectin, and laminin are glycoproteins found in the normal human cornea; however, their comparative distribution across the corneal layers has not yet been determined. Nonetheless, there have been controversial reports describing their altered expression in corneal diseases. The aim of this study is to evaluate the expression of collagen 1A1, fibronectin, and laminin in all layers of the normal human cornea in adults and early childhood, in order to provide the basis for understanding the pathogenesis of various corneal pathologies.
Methods :
A total of 21, 29, and 29 adult and 9, 10, and 11 pediatric corneas were used to evaluate COL 1A1, fibronectin, and laminin expression, respectively. Immunohistochemistry was performed using a panel of antibodies against different isoforms of these glycoproteins. Immunostaining was classified based on intensity (negative=0, weak=1, strong=2) and extent (negative=0, staining ≤50% of the structure=1, staining >50% the structure=2). An immunoreactive score (IRS; intensity + extension) was calculated to describe the expression in each layer. Results were expressed in the following manner: 0=negative (-), 1-2=weak (+), 3-4=strong (++). Analysis of variance (ANOVA) was performed to determine if there were expression differences in adult versus pediatric corneas, or central versus peripheral expression within groups.
Results :
Each marker demonstrated variable staining within the different layers of normal human corneas. Overall, however, there were no significant differences in glycoprotein expression between adult and pediatric corneas (P > 0.05). Similarly, there were no significant differences in glycoprotein expression in central versus peripheral corneas (P > 0.05).
Conclusions :
To the best of our knowledge, this is the first report comparing COL 1A1, fibronectin, and laminin expression throughout the corneal layers. The knowledge of normal corneal expression of these glycoproteins is the basis for further studies evaluating disease entities with aberrant expression, such as keratoconus or corneal dystrophies.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.