Abstract
Purpose :
To evaluate γ-glutamyltranspeptidase (GGT) expression with inflammation/oxidative stress markers in corneal epithelial cell layers of enucleated eyes of patients with diabetes mellitus (DM) and without (NDM).
Methods :
Pathology sections of 15 painful blind enucleated eyes [7 with and 8 without DM] were stained by immunohistochemical or immunofluorescent antibody methods. The label distribution and density levels of GGT, 8-hydroxydeoxyguanosine (8-OHdG), annexin V (AnxV), aldose reductase (AR), and cystine/glutamate exchanger (xCT) were analyzed microscopically using imagej.gov software to assess stain densities in basal columnar (ColEC), superficial squamous (SSEC), and surface (SEC) epithelial cells.
Results :
GGT and 8-OHdG positive ColECs were detected in all corneas. GGT labeling was detected in ColEC in 100% of NDM and 86% of DM corneas. GGT and 8-OHdG labeling were weak in SSEC of 11 (73%) corneas accounting for significantly lower SSEC GGT and 8-OHdG levels. SSEC GGT were significantly lower than ColEC and SEC label densities in NDM and DM corneas (p’s≤0.03). Nuclear membrane 8-OHdG was detected in 4 NDM and 4 DM corneas. 8-OHdG was lower in SSEC and SEC of DM cornea (p’s≤0.03). Perinuclear ColEC vacuolation was detected in 1 DM and 3 NDM corneas with loss of endothelial cells. AnxV was detected in ColEC of 3 NDM and 1 DM cornea, was highest SEC, but was not localized with 8-OHdG or GGT. AR was detected in all DM corneas predominantly in SSEC resulting in significantly higher label densities than in NDM corneas (p=0.045). AR and xCT were co-localized in scattered SEC of 4 NDM corneas and in SEC of 1 DM cornea. AR was detected in 3 DM corneas with basal ColEC epitheliopathy. xCT labeling was detected in all epithelial cell layers of 4 corneas with ulcers.
Conclusions :
The results posit GGT and 8-OHdG as markers of metabolic activity in ColEC, inflammation/oxidative stress response in eyes with ulcerated corneas, and devitalized SSEC or agonal ColEC when absent. Nuclear 8-OHdG and AnxV labeling suggest DNA oxidation and cell death but were not co-localized. AR was detected in NDM and DM corneas and co-localized with xCT in SEC of corneas of 4 enucleated eyes. Corneal GGT density was lowest in aged DM eyes.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.