Abstract
Purpose: :
To compare the levels of GGT (elevated in plasma of diabetic patients) activity in corneal buttons (CB) from eye bank eyes.
Methods: :
Sixty-five human CB (51 non-diabetic and 14 diabetic CB deemed non-usable for corneal transplant) with endothelial cell counts and donor history were obtained through the auspices of the Southern Louisiana Eye Bank (New Orleans, LA). The 11mm CB were weighed and assayed for GGT activity using a standard colorimetric test based upon the conversion of gamma-glutamyl-p-nito-analine. GGT activity was calculated for whole CB and dissected corneal endothelium.
Results: :
The GGT activity in the non-diabetic CB (20.5 ±10 U/CB; mean age 50 ±15 yrs) was significantly higher (p=.018) than in the diabetic (12 type 1 and 2 type 2) CB (14.2 ±4 U/CB; mean age 63 ±5 yrs). The GGT activity/CB/gr wet weight was slightly higher in the non-diabetic (125 ±78 U/gr) versus diabetic CB (103 ±21 U/gr; p=0.08). The endothelial cell count in non-diabetic CB (2,719 ±333 cells/mm2) was similar to that of the diabetic CB (2,616 ±201 cells/mm2; p=0.28). However, the GGT activity in the diabetic CB group was significantly lower (p<0.0001) than in a group of 12 CB from patients whose cause of death was due to head trauma (30.1 ±14 U/CB; mean age 30 ±14 yrs). Concomitantly, the endothelial cell counts (2,951 ±333 cells/mm2) in the head trauma group was higher than in the diabetic CB group (p=<0.0001).
Conclusions: :
The results suggest that GGT activity is reduced in human central corneal tissue from diabetic patients. The results support the possibility that lower GGT activity in diabetic CB was associated with lower endothelial cell counts.
Keywords: cornea: endothelium • enzymes/enzyme inhibitors • diabetes