Results of ultrathin Descemet stripping automated endothelial keratoplasty with donor corneas preserved in synthetic organ culture media.

PURPOSE: To evaluate outcomes of ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) with donor corneas preserved at 31°C in Cornea Syn®, a medium formulated with recombinant human serum albumin (rHSA) to replace foetal calf serum, and deswelled-transported in the xeno-free medium Cornea Trans®. METHODS: Prospective, multicentre, open-label study. We evaluated the endothelial cell loss (ECL) as the percentage variation of the endothelial cell density (ECD, cells/mm2) between 6 and 12 months after surgery, corneal transparency and thickness at 12 months, and adverse events within 12 months. Endothelial lenticules of mean 89 µm, ECD ≥ 2300 cells/mm2, minimum signs of cell mortality or morphology alterations, were dissected by microkeratome in the eye bank, and grafted in patients ≥ 18 years without corneal neovascularisation, conjunctivalization, or blinking impairment. RESULTS: Thirty-five patients underwent UT-DSAEK, 3 showed primary failure, 1 late failure, and 2 skipped the 6-month visit. We analysed data from 29 patients, 27 with Fuchs endothelial corneal dystrophy (FECD) and 2 with pseudophakic bullous keratopathy (PBK). The median ECL between 6 and 12 months was 2.6% (p = .054, CI 0 to 12.5) and the absolute mean (SD) was 158.4 (364.1) cells/mm2. After 12 months, 96.5% of corneas were clear, with mean pachymetry of 585.9 (50.4) µm. CONCLUSIONS: The ECL rate after UT-DSAEK match overall that observed in DSAEK or UT-DSAEK models of endothelial survival and the overall safety compared that reported for similar follow-up. Corneas maintained in Cornea Syn® and Cornea Trans® did not affect the ECD and functional outcomes of UT-DSAEK up to 12 months.

Recombinant human serum albumin for corneal preservation.

PURPOSE: To study the performance of a completely synthetic organ culture (OC) preservation system containing recombinant human serum albumin (rHSA) for preservation of human donor corneas. METHODS: Twenty-four paired donor corneas were randomly collected, and one cornea from each donor was preserved in synthetic (experimental) and serum-based media (control). The tissues were assessed at day 0; after 6 days of preservation at room temperature (RT) in Cornea Trans® and Cornea Prep II® ; after 28 days at 31°C in Cornea Syn® [with rHSA] and Cornea Max® [with foetal calf serum (FCS)] and; 4-day post deswelling in Cornea Trans® and Cornea Jet® . Thickness was determined with optical coherence tomography (OCT) and transparency with a validated, custom device. Morphology, endothelial cell density (ECD) and mortality were observed after treating the tissues with Trypan blue and sucrose. Glucose uptake by the cells was analysed. Data were compared using non-parametric paired Wilcoxon tests with p < 0.05 deemed significant. Histology using periodic acid-schiff (PAS), expressions of p63, CK12, αSMA and ZO-1 were analysed, and cell apoptosis postpreservation was studied. RESULTS: Corneas stored in synthetic media showed a higher and statistically significant value as compared to serum-based media in terms of viable endothelial cell density (VECD), mortality, morphology and glucose uptake postpreservation. Histology showed presence of all the layers, all the markers were expressed, and no apoptosis was observed in either media. CONCLUSION: The new synthetic preservation system containing rHSA (and other confidential constituents) showed better preservation effects than traditional media containing serum.

A quantitative method to evaluate the donor corneal tissue quality used in a comparative study between two hypothermic preservation media.

To standardize a new evaluation technique for calculating the overall quality (OQ) of the donor cornea and validate it using a comparative study of corneas preserved in Optisol-GS and Cornea Cold®. Thirty pairs of donor corneas were selected for a 4 week in vitro comparative study using masked observers. Physiological parameters like thickness, transparency, viable endothelial cell density (VECD) and morphology were transformed to numerical range (0-4) to obtain the OQ. Microbiological examination was performed using Bactec instrument. Students t test showed statistically better results (p < 0.05) from week 3 for thickness, week 2 for transparency and week 1 for morphology and VECD; statistical significance (p < 0.05) was found for OQ from week 2 for the corneas preserved in Cornea Cold® compared to Optisol-GS. Epithelial quality was similar regardless of the medium. Microbiological examination showed absence of aerobic and anaerobic microorganisms in both media. OQ method is efficient, consistent and easy, now validated for comparative studies. Further refinement is necessary for its use at eye-banks, bio-banks and research or transplantation purposes. Cornea Cold® is a promising hypothermic corneal storage medium with preservation time ≤21 days. This permits higher flexibility, evaluation accuracy, longer duration for surgical preparation and ease of transportation.