Endothelial and smooth muscle changes of the thoracic and abdominal aorta with various types of cryopreservation

Background. There is a need for cryopreserved arterial allografts in vascul ar surgery. Vitrification was examined as an alternative to slow cooling. F unction of endothelial and adjacent cells was evaluated in the thoracic and abdominal regions of the porcine aorta. Material and Methods, Aortas from young pigs were harvested and cryopreserv ed with several treatments: slow cooling at 1 degrees C/min with 10% dimeth yl sulfoxide (DMSO) and vitrification with a vitrification solution (VS), p erformed either in the presence (medium) or in the absence (air) of the cry oprotective medium surrounding the sample. Tetrazolium salt reduction and o xygen consumption were used to assess the mitochondrial activity of the end othelial cells and smooth muscle cells from the aorta. Results. Fresh aorta showed an increased function from below the aortic arc h to the iliac branch. Exposure to cryoprotective solutions reduced signifi cantly the oxygen consumption of the abdominal. sections. Samples from the thoracic region had a better response to cryopreservation than those from t he abdominal region. There was a significant reduction in tetrazolium salt reduction and oxygen consumption when the samples were cryopreserved immers ed in the medium. Significant flaking of the endothelium was observed after vitrification and contributes generally to lower the function. Conclusion. The thoracic region of the aortic wall was more tolerant to the preservation injury, and freezing with DMSO in air offered a better choice of preservation. (C) 2000 Academic Press.