Functional analysis of cryopreserved veins

Abstract

Functional comparisons of cryopreserved and fresh canine vein endothelium, smooth muscle, and connective tissue were performed. Morphometric analysis of saphenous vein endothelium revealed no significant loss of endothelial integrity as a result of cryopreservation. Endothelial cell culture revealed similar numbers of clonogenic intimal cells from cryopreserved and fresh saphenous, cephalic, and jugular veins. Smooth muscle function was assessed by measurement of the isometric force generated by vein rings in response to norepinephrine, serotonin, and potassium chloride. There was no significant difference in the dose responses of cryopreserved and fresh saphenous veins to the reagents tested. Similar results were obtained for the cephalic and jugular vein experiments with norepinephrine. The maximum tensions generated in response to norepinephrine were 52% of fresh control segments. Connective tissue function was assessed by quantitation of 3H-proline incorporation. The results indicate that cryopreserved veins retained approximately 43.5% of values of fresh vein collagen synthesis. Finally, eight cryopreserved cephalic vein autografts were placed as femoral artery grafts and were removed electively after 1 to 8 weeks. All grafts were patent. Both light and electron microscopy demonstrated that the cryopreserved veins remained intact in vivo and that arteriolization occurred as described for fresh autografts in the literature. In conclusion, cryopreserved veins retain much of their cellular and tissue functions on thawing. Transplantation of cryopreserved veins suggests that cryopreservation does not change the sequence of histologic events associated with the use of autologous fresh vein as an arterial substitute.

Venous reflux repair with cryopreserved vein valves

“…Thermal fractures, 50% decrease of smooth muscle and connective tissue function, and marginal decrease of venous compliance have been described. 13,14 Repaired valves did not fare any worse than nonrepaired valves.…”

Use of cryopreserved cadaveric vein allograft for hemodialysis access precludes kidney transplantation because of allosensitization

“…Attempts to use venous allografts as an alternative vascular conduit in patients with inadequate autogenous vein for either distal vascular reconstruction or heart revascularization have met with uniformly poor results. [5][6][7][8][9][10] The introduction of rate-controlled freezing and the cryopreservant DMSO has resulted in the preservation of up to 80% of the vascular endothelium during the cryopreservation process. 1,2 These DMSO-cryopreserved femoral veins have been indicated for use in liver transplantation as conduits to attach the hepatic artery or portal vein, as venous valve replacements in patients with chronic venous insufficiency, and as conduits for arteriovenous fistulas when suitable autogenous material is not available.…”

Current Status Of Cryopreserved Saphenous Vein Homografts

“…Brockbank has documented maintenance of overall intimal integrity despite loss of a significant number of endothelial cells. 22 Significant endothelial denudation occurs after implantation into the arterial system. Faggioli has similarly documented some endothelial denudation after implantation in the arterial system in rabbits .2' The maintenance of antithrombotic properties, fibrinolytic activity and prostacyclin production has also been documented in cryopreserved veins.23,24 Platelet adhesion is not increased in an animal model of cryopreserved vein bypasses.25 However cryopreserved veins do appear to accumulate LDL cholesterol at a higher rate than nonpreserved veins in an in vitro experiment suggesting some loss of endothelial integri-.t-~,.26 The ability of the graft to respond appropriately to EC dependent relaxation to acetylcholine, thrombin and calcium ionophore A23187 in animal studies further document the viability of the cells after transplant.…”

“…Although cryopreservation may preserve the morphological appearance of the vein graft, [15][16][17]21,22 questions have remained about the biological activity of the conduit. Most studies have documented an intact endothelium after cryopreservation.…”