Abstract
Purpose: :
To evaluate the biological condition of corneal stroma and the viability of corneal endothelium by microkeratome in internationally shipped pre-cut donor corneas for Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK).
Methods: :
Eight pre-cut donor corneas and 6 non-cut donor corneas (control) were obtained from SightLife (Seattle, WA). After removal of the graft flap including endothelium for transplantation, cryosections made from the remaining portion of the corneas were histologically and immunohistologically examined including TUNELstaining. To assess cell viability in corneal endothelium, biostaining experiments were performed using propidium iodide (PI), calcein-AM, and Hoechst 33342 dye with the 8 pre-cut corneas and 6 non-cut corneas.
Results: :
Histological examination demonstrated a smooth surface on pre-cut donor corneas. The positive cells of Ki67, a cell proliferation marker, and smooth muscle actin, a myofibroblast phenotype marker, were not found around the cutting plane. Fibronectin was found faintly around the cross-cutting plane of the corneal peripheral portion. Tenascin-C, which is expressed in stressed cells, was found weekly at the cells around the cutting plane of the peripheral and cap portion. The positive cells of TUNEL staining were found scarcely around the cutting plane. The control corneas were stained negative for all staining. Cell viability testing showed that the endothelial cell density (ECD) was 2344.0 +/- 355.2 (control: 2922.2 +/- 433.7), and the dead cell rate (DCR) was 3.6 +/- 2.8% (control: 8.2 +/- 2.8%).
Conclusions: :
Compared with the control corneas, the pre-cut corneas showed a significantly lower ECD, however, the DCR was also lower thus helping to maintain the postoperative endothelium. Histological and immunohistological examination of the corneal stroma and viability testing of the corneal endothelium revealed that the pre-cut corneas can safely be used for DSAEK. Although long-term clinical observation is still required in order to draw a definite conclusion, pre-cut donor corneas prepared at Eye Bank and shipped from the United States to Japan were considered to be useful for DSAEK.
Keywords: immunohistochemistry • cornea: endothelium • cornea: stroma and keratocytes