Assessment of performance and safety of Corneal Chamber hypothermic storage medium and PSS-L corneal rinsing solution in human and porcine corneas

Abstract

Purpose: To prove the safety and performance of the hypothermic corneal storage medium "Corneal Chamber" and the rinsing solution "PSS-L" in support of the new Conformité Européenne (CE) certification process in accordance with the Medical Device Regulation.

Methods: Fifteen (n=15) human donor corneas and 11 (n=11) porcine corneas were evaluated for the following parameters: endothelial cell density (ECD) and mortality, percentage of hexagonal cells (HEX%), coefficient of cellular area variation (CV%) and corneal transparency at Day 0 and after 14±1 days of storage in Corneal Chamber medium at 2-8°C. Then, the same parameters were assessed after rinsing of corneas in PSS-L for 1 min at room temperature. Evaluation of gentamicin sulfate carryover after corneal storage and PSS-L rinsing was performed by ultra-high performance liquid chromatography analysis on human corneas homogenates.

Results: Human and porcine corneas stored in Corneal Chamber medium showed a good overall quality of the tissue according to the quality parameters evaluated. In particular, mean ECD, HEX% and CV% did not show statistically significant changes at the end of storage and endothelial mortality increased to 3.1±3.3 and 7.8±3.5% in human and porcine corneas, respectively. Tissue rinsing with PSS-L did not affect the quality parameters evaluated before and gentamicin sulfate residues were absent in human corneas.

Conclusions: Corneal preservation in Corneal Chamber medium at 2-8°C for 14 days and the corneal rinse with PSS-L are safe and effective procedures allowing the preservation of the corneal quality parameters as well as the complete elimination of gentamicin sulfate from the tissues before transplantation.Cite Now.

Keywords: Anterior chamber; Cornea; Diagnostic tests/Investigation; Drugs; Experimental & animal models; Experimental & laboratory; Imaging; Treatment Surgery.

Figure 1

Endothelial cell density (ECD, A) and percentual ECD change (B, both light microscopy—n=11—and specular microscopy—n=7—), endothelial mortality (C, n=15), HEX% (D, n=7), CV% (E, n=7) and transparency (F, n=15) of human corneas before (Day 0) and after (Day 14) hypothermic storage in Corneal Chamber Medium (CCM) for 14 days at 2–8°C, and after rinsing of corneas in PSS-L for 1’ at room temperature (Day 14^PR). **: p<0.01, ***: p<0.001. CV, coefficient of cellular area variation; HEX, hexagonal cells.

Figure 2

Representative pictures of human (A, B) and porcine (C) corneal endothelium before (Day 0) and after (Day 14) hypothermic storage in CCM for 14 days at 2–8°C, as well as post rinsing of human corneas into PSS-L for 1’ at room temperature (Day 14^PR). Left panels (A, C): light microscopy evaluation after trypan blue staining at the different time points of human (A) and porcine (C) endothelia (scale bar: 100 µm). Central panels (A, C): magnifications of light microscopy left panels (scale bar: 100 µm). Right panels (A, C): specular microscopy evaluation at the different time points of human (A) and porcine (C) endothelia (scale bar: 100 µm). (B) Representative images of human corneal endothelium stained with Alizarin Red dye (left, scale bar: 100 µm) and of human Descemet membrane endothelial keratoplasty grafts (right, scale bar: 100 µm) after 14 days of hypothermic storage in CCM followed by PSS-L rinsing (Day 14^PR). CCM, Corneal Chamber medium.

Figure 3

Immunofluorescence analysis on Descemet membrane endothelial keratoplasty grafts showing expression of the structural tight junction associated protein ZO-1 and functional alpha-1 Na⁺/K⁺ ATPase pump on human corneal endothelium after 14 days of hypothermic storage in Corneal Chamber medium followed by PSS-L rinsing (scale bar: 100 µm).