[Effect of serum and osmotically active substances on metabolism in 262 tissue cultures of pig's corneas--improved preservation of donor tissue for keratoplasty]

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.

Poloxamines for deswelling of organ-cultured corneas

BACKGROUND

Poloxamines are amphiphilic tetrofunctional block copolymers composed of four polyoxyethylene-polyoxypropylene arms joined to a central ethylene diamine bridge. Their safe profile allows diverse pharmaceutical and biomedical applications.

AIM

To assess their use for corneal deswelling using a porcine model of organ culture (OC).

METHODS

Five poloxamines (T90R4, T904, T908, T1107 and T1307) were dissolved in a standard commercial OC medium (control) to reach 350 mosm kg(-1). In vitro cytotoxicity was tested using MTT assay on human corneal epithelial and endothelial cell (EC) lines and on primary human corneal fibroblasts. Paired porcine corneas stored in OC for 3 days were assigned for 48 h to a poloxamine medium or to a standard deswelling medium containing 5% dextran T500. Corneal EC density, morphometry, mortality, stromal thickness and transparency were evaluated before and after deswelling. Post-deswelling, EC viability/mortality was determined using a fluorescent live/dead assay.

RESULTS

Besides similar corneal thickness reduction and transparency improvement, T908, T1107 and T1307 decreased EC loss (5.4 ± 1.7% vs. 9.9 ± 2.6% in controls (p < 0.001)) and mortality, improved EC morphometry and reduced endothelial lesions compared to dextran.

CONCLUSION

On this porcine model, poloxamines T908, T1107 and T1307 appear as good candidates to replace dextran for the deswelling. Experiments on human corneas are now necessary to confirm their efficiency and safety profile in OC.