Time course of glomerular endothelial injury related to pulsatile perfusion preservation

To elucidate the time course of glomerular and arterial endothelial injury resulting from pulsatile perfusion preservation of human kidneys, we examined two kidneys, one at 16 and the other at 42 hr, for which no suitable recipient could be found. The scanning electron microscope revealed subtle changes at 16 hr in the filtration barrier. These included mild endothelial swelling with an increase in the appearance of bulbous processes, and elongated fenestrae. The visceral epithelial surface was normal as was the arterial endothelial surface. By 42 hr the glomerular endothelial surface displayed very prominent cytoplasmic ridges and clearly distorted fenestrae. The arterial endothelium exhibited a tendency to separate from the vessel wall. The proximal tubular epithelium revealed scattered loss of microvilli. These changes are similar in kind to, albeit less severe than, those described after 60 hr of perfusion. They may represent cell swelling following ischemia, or be the result of altered cell permeability engendered by low temperature. The possibility remains that such changes could be minimized by modifying the perfusate. Scanning electron microscopy provides a versatile tool in the study of vascular and other surfaces of tissues stored with perfusion preservation.