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The effects of high molecular weight dextran on the preservation of human corneas
Abstract:
Paired human corneas (48) were preserved at 31 degrees C for different periods of time up to 122 days in a modified MEM tissue culture medium free of or supplemented with 8% dextran T500. Cell density and vitality of the endothelial cells were analysed using morphometry, light microscopy after trypan blue staining, followed by sucrose provoked swelling and fine structural observations. Culturing for periods up to 7 weeks resulted in an endothelial cell loss of 11% of dextran-blue and of 15% in dextran-supplemented medium. For preservation periods between 9-13 weeks, these values were 43% and 36% respectively. The differences between dextran-free and dextran-supplemented preservation media were not significant. As deduced from trypan blue staining, sucrose provoked swelling and fine structural observations; the remaining cells were vital. Dextran was taken up by the endothelial cells. The practical consequences of endothelial cell loss and the toxic effects of dextran are discussed in relation to penetrating keratoplasty.
Insights
Corneal endothelial cell loss increases significantly after 7 weeks of preservation. Dextran T500 supplementation did not significantly alter cell loss or vitality in modified MEM medium.
Area of Science:
- Ophthalmology
- Tissue Engineering
- Cell Biology
Background:
- Corneal preservation is crucial for penetrating keratoplasty success.
- Endothelial cell health is vital for graft survival and function.
- Optimizing preservation media is essential to minimize cell loss.
Purpose of the Study:
- To evaluate the impact of dextran T500 on human corneal endothelial cell preservation.
- To assess endothelial cell density and vitality after extended storage periods.
- To determine the potential toxicity of dextran in corneal storage media.
Main Methods:
- Human corneas (n=48) were preserved in modified MEM medium with or without 8% dextran T500 at 31°C.
- Endothelial cell density and vitality were assessed using morphometry, trypan blue staining, and light microscopy.
- Sucrose-provoked swelling and fine structural observations were utilized for vitality assessment.
Main Results:
- Endothelial cell loss was 11% (dextran-free) and 15% (dextran-supplemented) up to 7 weeks.
- Cell loss increased significantly to 43% (dextran-free) and 36% (dextran-supplemented) between 9-13 weeks.
- No significant difference in cell loss or vitality was observed between media formulations.
- Dextran uptake by endothelial cells was noted, with remaining cells showing vitality.
Conclusions:
- Extended corneal preservation beyond 7 weeks leads to substantial endothelial cell loss.
- Dextran T500 supplementation does not significantly improve or worsen endothelial cell preservation in this medium.
- Potential toxic effects of dextran on corneal endothelial cells warrant further investigation for penetrating keratoplasty applications.