Lysosomal enzyme abnormalities in keratoconus
S. Sawaguchi, B. Y. Yue, J. Sugar and J. E. Gilboy
Department of Opthalmology, Lions of Illinois Eye Research Institute, University of Illinois, College of Medicine, Chicago 60612.
We studied the lysosomal enzyme activities in corneas obtained from 12
patients with keratoconus. Three acid hydrolases--acid phosphatase, acid
esterase, and acid lipase--were demonstrated by histochemical staining
methods in the epithelium, stroma, and endothelium of corneas with
keratoconus and normal human corneas. Analyses by an image-processing
system indicated that the epithelium, especially the basal epithelium, of
corneas with keratoconus had significantly higher levels of acid
phosphatase, acid esterase, and acid lipase than those in normal human
controls. Such an abnormality was not seen in either scarred corneas or
corneas obtained from patients with Fuchs' corneal dystrophy. Our finding
is consistent with the hypothesis that tissue degradation processes may be
abnormal in keratoconus. In addition, our data suggest that the corneal
epithelium, as previously speculated, may also be involved in this corneal
disease.
