Corneal Endothelial Cell Integrity in Precut Human Donor Corneas Enhanced by Autocrine Vasoactive Intestinal Peptide

Purpose: To demonstrate that vasoactive intestinal peptide (VIP), a corneal endothelial (CE) cell autocrine factor, maintains the integrity of corneal endothelium in human donor corneoscleral explants precut for endothelial keratoplasty. Methods: Twelve paired human donor corneoscleral explants used as control versus VIP-treated explants (10 nM, 30 minutes, 37 degrees C) were shipped (4 degrees C) to the Lions Eye Institute for Transplantation and Research for precutting (Moria CBM-ALTK Keratome), shipped back to the laboratory, and cultured in ciliary neurotrophic factor (CNTF, 0.83 nM, 37 degrees C, 24 hours). Trephined endothelial discs (8-8.5 mm) were analyzed for differentiation markers (N-cadherin, CNTF receptor a subunit [CNTFRa], and connexin 43) by Western blot after a quarter of the discs from 4 paired explants were cut away and stained with alizarin red S for microscopic damage analysis. Two additional paired explants (6 days in culture) were stained for panoramic view of central CE damage. Results: VIP treatment increased N-cadherin and CNTFRa levels (mean 6 SEM) to 1.38 +/- 0.11-fold (P = 0.003) and 1.46 +/- 0.22-fold (P = 0.03) of paired controls, respectively, whereas CE cell CNTF responsiveness in upregulation of connexin 43 increased to 2.02 +/- 0.5 (mean 6 SEM)-fold of the controls (P = 0.04). CE damage decreased from (mean 6 SEM) 10.0% +/- 1.2% to 1.6% +/- 0.3% (P < 0.0001) and 9.1% 6 1.1% to 2.4% +/- 1.0% (P = 0.0006). After 6 days in culture, the damage in whole CE discs decreased from 20.0% (control) to 5.5% (VIP treated). Conclusions: VIP treatment before precut enhanced the preservation of corneal endothelium.