Function of cryopreserved arterial allografts under immunosuppressive protection with cyclosporine A

Cryopreserved arterial allografts may be used for arterial reconstructive procedures. In this experimental study cryopreserved arteries were used as autografts and as allografts with or without immunosuppression with cyclosporine A.

In group A (three dogs, six bilateral grafts) cryopreserved carotid artery autografts were implanted. In groups B and C female mongrel dogs (three dogs and six bilateral grafts in each group) received cryopreserved male carotid artery allografts. 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 endothelium-dependent relaxation response to methacholine (Met) were examined in segments of the grafts after excision. Medial thickness was assessed semiquantitatively. The grafts were stained for sex chromatin analysis to determine the origin of cells in allografts.

Patency: group A, 100% (6 of 6), group B, 66.6% (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 (KCl), 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 characteristics: the media of grafts in group B showed significant thinning (p < 0.05). Smooth-muscle cells in vessel walls of grafts in group C were of female origin.

Arteries showed no function and loss of endothelial integrity after cryopreservation and thawing. After 3 months of implantation cryopreserved arterial autografts and allografts under immunosuppressive treatment with cyclosporine A showed 100% patency and return of functional responses resulting from repopulation of grafts by host cells.