Normal expression levels of cathepsins, protease inhibitors, and Sp1 in conjunctival tissues from patients with keratoconus

Purpose. In keratoconus corneas, it has been shown that levels of degradati ve enzymes and transcription factor Sp1 are elevated and those of inhibitor s are reduced, especially in the epithelial layer. This study is to determi ne whether the biochemical abnormalities identified in corneas also exist i n conjunctival tissues. Methods. Conjunctival tissues were collected from normal subjects and from patients with keratoconus, senile cataract, and other corneal diseases. Imm unohistochemical staining for cathepsins B and G, alpha1-proteinase inhibit or, alpha2-macroglobulin and Sp1 was performed. Results. The epithelium of all conjunctival specimens showed immunoreactivi ty toward the antibodies. The staining for cathepsins B and G, and the inhi bitors was mostly cytoplasmic, while that for Sp1 was nuclear. The staining intensity in keratoconus specimens was all within normal range. Conclusions. These results suggest that the abnormalities in cathepsins B a nd G, protease inhibitors and Sp1 identified in keratoconus corneas are not manifested in the conjunctiva. Keratoconus appears to be a disease localiz ed to the cornea.