Name

183 - Une machine de conservation active pour les cornées permet une délivrance de greffons jusqu'à 3 mois après prélèvement

Our university laboratory BiiGC patented an Active Storage Machine (ASM), also called bioreactor for long-term eye banking (in process of industrialization). By restoring intraocular pressure and medium renewal, it maintains viability of corneas over a prolonged period, without deswelling step contrary to standard organ-culture (OC). Moreover, tissue quality controls are possible at any time without deconditioning corneas. In a previous study we showed that after 1-month storage, there were 1.6 times more corneas suitable for graft in ASM than in OC, with 23% more viable endothelial cells (ECs). Aim: To assess whether it is possible to extend storage up to 3 months.

12 pairs of corneas with initial endothelial cell density (ECD) >2000 cells/mm2 and <10% difference between both corneas randomly stored with the same commercial medium CorneaMax (Eurobio), with same batch number: one in ASM (21mmHg, 2.6μL/min of medium renewal), the other in OC (100mL of medium renewed every 3 weeks). Primary endpoint: ECD monitored by non-invasive specular microscopy in ASM at D2, M1, M2, M3 and by transmitted light microscopy in OC at D2, M3 (deswelling step 2 days before end of study for corneas in OC). Corneas were defined as suitable for graft if ECD remained >2000 cells/mm2 and for emergency if ECD remained >1600 cells/mm2. Secondary endpoints: transparency (transparometer), central corneal thickness (CCT by SD-OCT), microbiological tests. At M3 (end of storage), pancorneal viable ECD (Hoechst/Ethidium/Calcein-AM), histology, ECs structure/functions (immunostaining, western blot).

At D2, ECD in ASM versus (vs) OC: 2718±295 vs 2779±396 cells/mm2 (p=0.250).

At M1 in ASM: 2331±259 cells/mm2 with 11/12 corneas suitable for graft and 1/12 for emergency.

At M2 in ASM: 1897±208 cells/mm2 with 5/12 corneas suitable for graft and 6/12 for emergency.

At M3, ECD in ASM vs OC: 1840±216 vs 1479±237 cells/mm2 (p<0.001), with 4/12 corneas suitable for graft and 7/12 for emergency in ASM vs respectively 0/12 and 4/12 in OC.

No contamination occurred in both groups. Corneas remained thin and transparent all along the 3 months of storage in ASM. T didn’t differ between both groups (p=0.921) and CCT was thinner in OC with 481±75 vs 640±49 μm in ASM (p=0.001) thanks to deswelling step.

At the end of storage, the viable ECD was 31% higher in the ASM than in OC (p<0.001) ; ECs structure/functions were much more preserved in ASM, in particular NaKATPase were 3 times more expressed than in OC (p=0.005), COXIV 1.5 times more expressed than in OC (p=0.019).

Hydration control from retrieval, thanks to our active corneal storage, results in better quality grafts not only during 1-month but also in keeping corneas with an in vivo-like status during 3-months. Epithelium was thicker and more differenciated in ASM, explaining higher CCT than in OC.

The Active Storage Machine (ASM) enables to extend corneal storage up to 3 months with unprecedented ECs viability. Moreover, it allows eyebanks to have corneas immediately available with normal or acceptable ECD for graft or emergency situations, thus optimizing grafts’ allocation.