NONFREEZING CRYOPRESERVATION - A POSSIBLE MEANS OF IMPROVING LONG-TERM TRANSPLANT FUNCTION

Improving organ preservation techniques for transplantation is one of the most important goals of transplantation research. We have establis hed a new, nonfreezing cryopreservation method to optimize the viabili ty of rat kidneys for transplantation with up to 4 M dimethylsulphoxid e (DMSO) in EuroCollins solution (EC) at -5 degrees C to -15 degrees C . We have confirmed the occurrence of a tubular and glomerular defect pattern that mediates acute tubular necrosis (ATN) and that may be a c ause of major histocompatibility complex (MHC) independent immunologic al components of chronic transplant rejection. The extent of this defe ct [transplant survival and function, P-31-NMR spectroscopy, histologi cal defect index] in the nonfreezing cryopreserved groups (n = 22) is significantly (P = 0.017) lower than in the simple cold storage group (n = 12). Quality and localization of the lesions in kidney transplant s can elucidate the context of organ preservation, progressive hyperfi ltration defects, and the occurrence of graft failure without elevated frequency of acute rejection episodes. These results indicate that fu rther efforts to provide higher pretransplant organ viability without using it to prolong cold storage intervals may provide better insight into MHC-independent factors of chronic transplant failure and may res ult in improved long-term transplant outcome.