Abstract
Purpose: :
To compare, characterize, and optimize different methods of glycerol preserved corneas intended for deep anterior lamellar keratoplasty (DALK).
Methods: :
We analyzed transparency, transmittance, thickness, biomechanics, morphology, and antigenicity of donor corneas preserved by 4 different glycerol-based methods (n=5 per group) for 6 months, as follows: 1) tissues in anhydrous glycerol with molecular sieves at room temperature (RT); 2) tissues in anhydrous glycerol without molecular sieves at RT; 3) tissues in anhydrous glycerol without molecular sieves at -78°C; 4) tissues in anhydrous glycerol without molecular sieves at -20°C. Fresh donor corneas served as a control group for these glycerol preserved corneas.
Results: :
slit lamp images and transmittance curves obtained by spectrophotometer show Group 3 was the most transparent tissue. A considerable increase was noted in the values of the modulus of elasticity in Group 1, as compared with other groups, show cornea tissues in Group 1 was least pliant. By both laser confocal microscopy and transmission electron microscopy, corneal cytoarchitecture and keratocyte integrity was destroyed in all glycerol preserved corneas. Disorganized stromal collagen fibers were evident in groups stored at RT. Antigenicity of tissue, assessed via immunohistochemistry for CD45 positive cells and HLA-ABC and HLA-DR, was lowered after glycerol preservation relative to fresh cornea tissues, especially in RT groups.
Conclusions: :
Anhydrous glycerol preservation without molecular sieves in -78°C freezer was the best method to obtain DALK-eligible tissues that were both transparent and pliable. All methods of glycerol preservation exhibited loss of cellular antigens that may decrease rejection risk.
Keywords: cornea: storage • microscopy: electron microscopy • cornea: clinical science