Abstract
Purpose:
Endothelial assessment is a critical step in the release of corneas for grafting. In addition to endothelial cell density (ECD), further criteria are applied to assess the morphology of the endothelium. We performed a retrospective study to determine the role of endothelial morphological parameters in predicting endothelial cell loss during organ culture.
Methods:
Human donor corneas were harvested and placed in minimal essential medium with 2% fetal calf serum, penicillin, streptomycin and amphotericin B. At the beginning of culture, endothelial morphology was assessed microscopically using the parameters polymegatism (POL), pleomorphism (PLE), granulation (GRA), vacuolization (VAC), segmentation of cell membranes (SEG), Descemet’s folds (DF), trypane blue positive cells (TBPC) and endothelial cell-free areas (ECFA), using standardized scores from 0 to 3. Some corneas were primarily rejected based on endothelial assessment. ECD was assessed at the beginning (I-ECD) and end of culture. Corneas were then placed in dehydration medium (as above + 5% dextran 500). In a subgroup, ECD was reassessed after dehydration. Endothelial cell loss during culture (ECL-C) and culture + dehydration (ECL-D) were calculated. Statistical analyses were performed using multiple linear regression and logistic regression, as appropriate (SAS/JMP11). Odds ratios (OR) were expressed per parameter level.
Results:
At initial assessment ECD was 2811+361/mm2 (n=2362). The decision to reject a cornea due to endothelial assessment was associated (r2 = 0.1760, p< 0.0001) with ECFA (p< 0.0001, OR = 2.7), SEG (p< 0.045, OR =1.3), I-EDC (p<0.0001, OR 0.997) and donor age (p<0.0001, OR 1.024). ECL-C was 153+200/mm2 (n=1277), ECL-D was 169+183/mm2 (n=918) with a culture duration of 19.71+6.5 days. ECL-C was associated (r2 = 0.081, p<0.0001) with DF (p<0.0001), TPBC (p=0.0011), GRA (p=0.0022), PLE (p=0.03), I-EDC (p<0.0001) and donor age (p<0.0053). ECL-D was associated (r2 = 0.228, p< 0.0001) with TPBC (p=0.0019), VAC (p=0.0003), PLE (p=0.0015), POL (p=0.0064), I-EDC (p<0.0001), donor age (p<0.0079) and gender (p=0.022).
Conclusions:
Several morphological parameters displayed significant predictive value for a primary exclusion of the corneas from culture and a significant correlation with endothelial cell loss. The selection of appropriate parameters may help to improve graft quality.