Fresh vein allograft survival in dogs after cyclosporine treatment

Synthetic grafts are widely used for peripheral arterial reconstructions when autologous veins are not available, but their results have not been satisfactory, Venous allograft may be used as an alternative to synthetic prostheses, The aim of the study was to explore the immunosuppressive efficacy of Cyclosporine A (CyA) as a means of preventing venous allograft failures and rejection. We utilized 56 mongrel dogs, Immunological incompatibility was checked with the skin graft method. Donor inferior vena cava was transplated into the infrarenal abdominal aorta of recipient animals. One group (group 1, 10 dogs) served as a control and three groups received CyA treatment regimens, Group 2 (10 dogs) received postoperative oral CyA treatment for 30 days. Group 3 (12 dogs) received a vein graft pretreated with a CS A solution without postoperative immunosuppressive therapy. Group 4 (9 dogs) received a vein graft pretreated with a CyA solution and postoperative CyA treatment for 30 days. Allografts were examined at 30 days for patency, aneurysmal dilatation, gross structural changes, inflammatory response, and lymphocytic infiltration. Sex chromatine assessment determined the origin (donor or recipient) of the endothelial cells. The allografts hom groups 1 and 3 showed significant aneurysmal dilatation and perivenous inflammation when compared to dogs treated with oral CyA therapy (P < 0.0002). Moreover allografts treated with CyA therapy had a better-developed venous neointima (P < 0.009) with less fibrin (P < 0.02), and thinner medial (P < 0.0009) and adventitial layers (P < 0.02). No significant differences were observed in neointimal thickness among the four groups. Lymphocytic infiltration was greater in the group of animals who did not receive oral CyA therapy (P < 0.0004), Barr bodies status showed significant differences between oral CyA treated groups and nontreated groups (P < 0.0003). Oral CyA therapy reduced aneurysmal dilatation and immunological response, promoted the development of a neoendothelium, and preserved the structure of the venous layers. Graft pretreatment with CyA flushing did not have a significant immunosuppressive effect. (C) 1996 Academic Press, Inc.