? Donated organs are used to extend life for thousands of people each year. Unfortunately, the availability of donor organs is greatly outweighed by current demand causing enormous shortages. The problem is compounded by the time critical nature of transplantation as the organ health begins to deteriorate rapidly during transport from donor to recipient. A mechanism that provided open-ended storage periods for donated organs would eliminate the detrimental effects of prolonged cold ischemia and improve organ transplant success by lifting time limits for improved tissue-typing and extended immunological preconditioning. The objective of this study is to determine if a new cryopreservation method using molecular ice control technology in a vitrification process can successfully block ice formation during preservation and permit long-term storage in a rat kidney model. We will evaluate vitrification solutions formulated with natural and synthetic molecular ice blocking compounds that are capable of limiting ice nucleation and growth. In this proposal, both in vitro and in vivo studies will be conducted to assess the viability and function of rat kidneys following vitrification with molecular ice control formulations and a standard vitrification solution. It is anticipated that solutions containing molecular ice control compounds will experience less ice formation than a standard vitrification solution and result in better renal function following transplantation. ? ?