Ultrastructural analysis of human endothelial cells after hypothermic storage in organ preservation solutions.

BACKGROUND: Protection of vascular endothelium is a critical factor in organ preservation for transplantation. This study aims at a morphological assessment of endothelial cell injury in a comparison of storage solutions, using a cell culture model of cold preservation and rewarming. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVEC) were cultured in monolayer and exposed to hypothermic storage in University of Wisconsin (UW), histidine-tryptophane-ketoglutarate (HTK), and EuroCollins solutions for 6 h and subsequent rewarming for 30 min or 6 h. Alterations of subcellular structures and cell-cell contacts were analyzed by transmission electron microscopy (TEM) and light microscopic assessment after actin and nuclear staining. RESULTS: Structural alterations of mitochondria, endoplasmic reticulum, nuclei, and cytoskeletal fibers as well as disruption of intercellular contacts were found after cold storage in HTK and EuroCollins solutions. In contrast, storage in UW solution resulted in minimum changes of stress fibers only. A rapid rearrangement of structural alterations was achieved during rewarming in cell culture medium in all experimental groups. CONCLUSIONS: Preservation of endothelial cell structure is best achieved by UW solution. Ultrastructural cell damage is a direct consequence of hypothermic storage and is fully reversible during rewarming after short storage times.