Ultrastructural observations in canine kidneys perfused hypothermically for 7 days in a comparative study of three preservative solutions

To determine the effectiveness of different renal perfusates, a comparison was made of the ultrastructure of canine kidneys perfused hypothermically for 7 days with (i) cryoprecipitated plasma (CPP); (ii) plasma protein fraction (PPF); or (iii) canine serum (CS). Each perfusate contained the reducing agents ascorbic acid and glutathione, and the redox level of the perfusate was maintained by potentiostatic control. Ultrastructural analysis was limited to the renal cortex from needle biopsies taken prior to perfusion, after perfusion, and 1-hr post-transplant. All kidneys failed soon after transplantation—turning dark, apparently from vascular blockage. In the CPP-perfused group some fibrin clotting was observed along with minor glomerular changes. The endothelium appeared continuous but beaded, and the epithelium showed retracted foot processes and/or villous extensions. The tubular areas displayed good cellular preservation. The post-transplant biopsies appeared similar, showing no further fibrin deposition but extensive erythrocyte blockage. In the PPF group, serious glomerular changes were observed after perfusion. Both the endothelium and epithelium lacked characteristic profile, and cytoplasmic inclusions were reduced. A flocculent precipitate was found in both the capillary lumen and the urinary space. The tubular regions in this group appeared to be well preserved. After transplantation, the PPF group showed progressive deterioration in both the renal corpuscle and tubules. Kidneys perfused with CS had some glomerular endothelial injury, but the epithelial cell appeared nearly undisturbed. In the tubular regions, the proximal and distal convoluted portions seemed well preserved but the intertubular capillary endothelium showed discontinuity. Upon transplantation, the ultrastructure was essentially similar. In all 1-hr transplant biopsies there was evidence of erythrocyte aggregation but no indication of fibrin or platelet clotting. From the ultrastructural observations made, it appears that significant endothelial injury did occur in the PPF and CS groups during the course of perfusion whereas little or no change was found in the CPP group.