FUNCTION OF CRYOPRESERVED ARTERIAL ALLOGRAFTS UNDER IMMUNOSUPPRESSIVEPROTECTION WITH CYCLOSPORINE-A

Purpose: Cryopreserved arterial allografts may be used for arterial re constructive procedures. In this experimental study cryopreserved arte ries were used as autografts and as allografts with or without immunos uppression with cyclosporine A. Methods: In group A (three dogs, six b ilateral grafts) cryopreserved carotid artery autografts were implante d. In groups B and C female mongrel dogs (three dogs and six bilateral grafts in each group) received cyropreserved male carotid artery allo grafts. Dogs in group C were treated with cyclosporine A (25 mg/kg/day ). After 3 months of implantation patency was assessed by angiography. Contractile responses to KCl and phenylephrine (Phe) and the endothel ium-dependent relaxation response to methacholine (Met) were examined in segments of the grafts after excision. Medial thickness was assesse d semiquantitatively. The grafts were stained for sex chromatin analys is to determine the origin of cells in allografts. Results: Patency: g roup A, 100% (6 of 6), group B, 66.60/b (4 of 6), and group C, 100% (6 of 6). Functional responses: before implantation, after thawing, 2.7 +/- 0.5 mN KCl), 4.8 +/- 1.0 mN (Phe), and 0.0% +/- 0.0% (Met), group A, 36.9 +/- 10.6 mN (KCI), 31.5 +/- 14.4 mN (Phe), and 59.3% +/- 20.4% (Met), group B, 0 for all agents used, group C, 34.0 +/- 7.5 mN (KCl) , 28.8 +/- 7.0 mN (Phe), and 46.2% +/- 3.2% (Met). Morphologic charact eristics: the media of grafts in group B showed significant thinning ( p < 0.05). Smooth-muscle tells in vessel walls of grafts in group C we re of female origin. Conclusion: Arteries showed no function and loss of endothelial integrity after cryopreservation and thawing. After 3 m onths of implantation cryopreserved arterial autografts and allografts under immunosuppressive treatment with cyclosporine A showed 100% pat ency and return of functional responses resulting from repopulation of grafts by host cells.