Characterization of stroma from Fuchs' endothelial dystrophy corneas.

Fuchs' endothelial dystrophy is commonly regarded as an endothelial cell disorder. In the present study we compared glycoconjugates of Fuchs' and normal corneas using FITC conjugated lectins [peanut agglutinin (PNA), castor bean agglutinin (RCA120), soybean agglutinin (SBA), and wheat germ agglutinin (WGA)]. Our results showed increased staining with RCA120 and PNA in the posterior region of the Fuchs' corneas, indicating an accumulation of terminal beta-galactose and B-D-galactose (1-3)-D-N-acetylgalactosamine residues. The stromal and epithelial regions of normal and Fuchs' corneas exhibited similar staining patterns with all lectins tested. Our collagen studies showed an increased extractability and abnormal amino acid analyses of collagen from Fuchs' corneas as compared with normals. The purified collagens did have similar banding patterns by sodium dodecyl sulfate gels. However, further characterization by 125(1) two-dimensional peptide mapping revealed that Fuchs' alpha 1-sized chains contained fingerprints that were distinctly different from normal cornea stromal collagen. These data suggest that in addition to abnormal accumulation of RCA120- and PNA-specific glycoconjugates in the posterior cornea, Fuchs' corneas contained stromal collagens with altered biochemical properties. We postulate that the characteristic deterioration of endothelial function in Fuchs' dystrophy may compromise the microenvironment of the stroma and its keratocytes, and thereby lead to an altered collagenous extracellular matrix.