Changes in the cooling rate and medium improve the vascular function in cryopreserved porcine femoral arteries

AbstractPurpose: The purpose of this study was to design an adequate technique with which to cryopreserve pig femoral arteries and to assess the influence of storage times in vascular function. Methods: Fifty-two femoral arteries were distributed in seven groups. In group A (control), 10 arteries were studied after harvest; in groups B1 and B2, 19 arteries were suspended in RPMI 1640 plus fetal calf serum plus dimethylsulfoxide and were cryopreserved at 1°C per minute or 0.3°C per minute, respectively. In groups C1 to C4, 23 arteries were suspended in modified Krebs-Henseleit plus dimethylsulfoxide plus sucrose, cryopreserved at 0.7°C per minute, and kept frozen for 1, 15, 60, or 180 days, respectively. After being thawed, arteries were examined for contraction and endothelial-dependent vasodilation (organ bath studies), antithrombotic properties of the endothelial layer(perfusion studies), and vessel structure (electron microscopy). Results: Endothelial cells were present in both cryopreserved and control arteries. The control vessels showed a mean contraction to norepinephrine (10–7 mol/L) of 13010 ± 3181 mg. Arteries in groups B1 and B2 did not respond to norepinephrine. Contraction in groups C1 to C4 was as follows: C1, 5354 ± 1222 mg; C2, 5187 ± 2672 mg; C3, 6867 ± 2292 mg; C4, 7000 ± 2858 mg, which represent 50% of the control values (P <.001). Vasodilation was similar in control (99% ± 3%) and cryopreserved arteries (C1, 90% ± 13%; C2, 93% ± 12%; C3, 89% ± 15%; C4, 88% ± 22%). Storage time did not influence vascular function. Platelet interaction was almost absent and similar in all groups. Conclusion: A modified cryopreservation technique preserves endothelial function independently of the storage time up to 6 months. (J Vasc Surg 2000;31:1018-25.