Abstract
Inadequate cross-linking between collagens is a characteristic feature of keratoconus (KC). The formation of bonds between collagen and elastin fibrils is mediated by the lysyl oxidase (LOX) and 4 LOX-like enzymes.
The aim of this study was to determine the distribution of LOX and the total LOX activity (LOX and 4 LOX-like enzymes) in control and KC corneas. The distribution of LOX was clearly decreased in at least 5 of the 8 KC specimens.
The most marked signal reduction was observed in the stromal matrix and in keratocytes. The signal in KC specimens revealed a more irregular pattern.
Endothelial cells showed no or very weak staining in areas just beneath negative stromal tissue. The mean activity of total LOX in the KC samples was lower than in control tissue and the decrease was statistically significant (p = 0.0178).
We hypothesize that the restricted LOX distribution in KC corneas, and particularly the decrease of total LOX activity in cultured keratoconic fibroblasts, is one potential reason for the inadequate collagen cross-linking that is a hallmark of this disease.