CRYOPRESERVATION OF THE MAMMALIAN KIDNEY .2. DEMONSTRATION OF IMMEDIATE EX-VIVO FUNCTION AFTER INTRODUCTION AND REMOVAL OF 7.5 M CRYOPROTECTANT

The objective of the present study was to determine whether rabbit kid neys could be perfused with a 7.5 M vitrification solution (VS4, which vitrifies under applied pressure) without loss of function. To answer this question, kidneys were perfused with VS4 using a computer-based machine to gradually raise and lower concentration and then attached t o the aorta and vena cava of a perfusor rabbit using an apparatus that permitted renal blood how and renal function to be measured. About ha lf (6/13) of the kidneys so evaluated resumed substantial immediate fu nction after a transient period of severely reduced blood flow. Loss o f function did not occur if cryoprotectant concentration was limited t o 3.8 M. The loss of function produced by VS4 could be partially repro duced by artificially limiting blood reflow in control kidneys to simu late the transiently low flows caused by VS4 exposure. These results p rovide the first evidence that both the parenchyma and the vascular sy stem of a sensitive mammalian organ can survive exposure to a vitrifia ble concentration of cryoprotectant. (C) 1997 Academic Press.