Advances in Clinical and Experimental Medicine
2018, vol. 27, nr 8, August, p. 1033–1036
Publication type: original article
Structural changes arising from different thawing protocols on cryopreserved human allograft’s aortic valve leaflets
1 2nd Department of Cardiovascular Surgery, General University Hospital, Prague, Czech Republic
2 1st Faculty of Medicine, Charles University, Prague, Czech Republic
3 Transplant Surgery Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
4 Department of Anatomy, Faculty of Medicine, Charles University, Hradec Králové, Czech Republic
5 Transplant Center, University Hospital Motol, Prague, Czech Republic
6 Department of Cardiovascular Surgery, Faculty Hospital Motol, Prague, Czech Republic
7 2nd Faculty of Medicine, Charles University, Prague, Czech Republic
8 Tissue Bank, Faculty Hospital Hradec Králové, Faculty of Medicine, Charles University, Czech Republic
9 2nd Internal Department of Cardiology and Angiology, General University Hospital, Prague, Czech Republic
Background. The aim of our experimental work was to assess the impact and morphological changes that arise during different thawing protocols on human aortic valve (AV) leaflets resected from cryopreserved aortic root allografts (CARAs).
Objectives. Two thawing protocols were tested: 1. CARAs were thawed at a room temperature (23°C); 2. CARAs were placed directly into a water bath at a temperature of 37°C. After all the samples were thawed, non-coronary AV leaflets were sampled from each specimen and fixed in a 4% formaldehyde solution before they were sent for morphological analysis.
Material and Methods. All the samples were washed in distilled water for 5 min and dehydrated in a graded ethanol series (70%, 85%, 95%, and 100%) for 5 min at each level. The tissue samples were then immersed in 100% hexamethyldisilazane (HMDS) for 10 min, and then air-dried in an exhaust hood at room temperature. Processed samples were mounted on stainless steel stubs and coated with gold. Histological analysis was performed with the use of an electron microscope on a scanning mode operating at 25 kV – BS 301.
Results. Thawing protocol 1 (room temperature at 23°C): 6 (100%) samples showed loss of the endothelial covering of the basal membrane with no damage to the basal lamina. Thawing protocol 2 (water bath at 37°C): 5 (83%) samples showed loss of the endothelial covering of the basal membrane with no damage to the basal lamina. One (17%) sample showed loss of the endothelial covering the basal membrane with significant damage to the basal membrane.
Conclusion. Based on our experimental work, we can clearly conclude that cryopreserved AV leaflet allografts show identical structural changes at different rates of thawing.
aortic valve, allograft, thawing, cryopreserved, structural changes
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